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Symposium on High-Temperature Well-Logging Instrumentation

Los Alamos National Laboratory Los Alamos, NM 87545 November 13-14,1985

Compiled by Bert R. Dennis

DECLAIMER

LA-1 0745-C Conference

UC-66b Issued: June 1986

This report was prepared as an account of work sponsored by agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability ix rtsponsi- bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or proctss disclosed, or represents that its usc would not infringe privately owned rights. Refer- ence herein to any specific commercial product, process, or scMcc by trade name, trademark, manufacturer, or otherwise docs not ncctSSarily .constitute or imply its endorsement, ream- mendation, or favoring by the United Statcs Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect thosc of the United States Government or any agency thenof.

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AS^^ Los Alamos National Laboratory Los Alamos,New Mexico 87545

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

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CONTENTS

' WELCOME TO LOS ALAMOS James E. Rannels, U.S. Department o f Energy.. ............................. George C. Phi lpot , The Rochester Corporation.. ............................

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DESIGN AND MANUFACTURING CONSIDERATIONS FOR TFE-INSULATED CABLES 3

FM MULTIPLEX FOR ARMORED LOGGING CABLE Evon L. Stephani, Los Alamos National Laboratory .......................... 5

MINERAL- INSULATED CABLES Barry W. Palmer, BICC Pyrotenax LTD ....................................... 13

MATERIALS TESTING/ARMORED LOGGING CABLE Tracy A. Grant, Los Alamos National Laboratory ............................ HIGH-TEMPERATURE CABLEHEAD Jose U. Crut, Los Alamos National Laboratory... ........................... SMOOTHWALL LOGGING CABLES

Inc.. ................................

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Arthur Halpenny, Halpen Engineering, 25

MATERIALS ISSUES I N HIGH-TEMPERATURE ELECTRONICS Randall K. Kirschman..................... ................................. 27

29 BURR-BROWN WIDE-TEMPERATURE PRODUCTS George L, H i 11 . Burr-Brown Research Corporati on .......................... HIGH-TEMPERATURE MICROELECTRONICS Tom Elsby, White Technology, Inc.....*....................~.........*..... 33

NEW CAPABILITIES I N PYROFLASKS R. W. Blanton, Vacuum Bar r i e r Corporation. ................................ 35

GEOTHERMAL INSTRUMENT THERMAL PROTECTION G lo r ia A. Bennett, Los Alamos National Laboratory. ........................ THE THEORY AND DESIGN OF DOWNHOLE THERMAL PROTECTION SYSTEMS FOR DOWNHOLE INSTRUMENTATION

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Richard L. Hack, PDA Engjneering .......................................... Raymond L . Jermance, Los A1 amos National Laboratory. ......................

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51 CROSSWELL ACOUSTIC TRANSCEIVER

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DEVELOPMENT OF A NEW BOREHOLE ACOUSTIC TELEVIEWER FOR GEOTHERMAL APP L I CATIONS Troy K. Moore, Los Alamos National Laboratory.. ........................... 57

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. SPUTTERED THIN-FILM STRAIN-GAGE PRESSURE TRANSDUCER FOR HIGH-TEMPERATURE APPLICATIONS Robert Backus, CEC Instrument D i vision/Joseph A. Catanach, Los Alamos National Laboratory.. ..................................................... 63

Jerry Kolar, Los Alamos National Laboratory.. ............................. S. E. Haggard, Mark Products U.S., Inc.. ..................................

Daniel McMahon, Endevco.. ................................................. 83

USE OF HIGH-TEMPERATURE TRANSDUCERS I N GEOTHERMAL WELL LOGGING 65

HIGH-TEMPERATURE VELOCITY TRANSDUCERS 75

I A HIGH-TEMPERATURE TRANSDUCER FOR MEASURING LOW-LEVEL DIFFERENTIAL PRESSURES I N A HIGH-STATIC PRESSURE FIELD

PASSIVE ACOUSTIC MEASUREMENTS I N GEOTHERMAL WELLS Manuel Echave, Los Alamos National Laboratory.. ........................... 87

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FLUID SAMPLER Jacobo Archuleta, Mechanical Design Services.. ............................ 91

INTERPRETATION OF WELL LOGS TO SELECT PACKER SEATS I N OPEN-HOLE SECTIONS OF GEOTHERMAL WELLS Ber t R. Dennis, Los Alamos National Laboratory............................ 93

HIGH-TEMPERATURE COMPONENTS.. ............................................. 99

MANUFACTURERS OF HIGH-TEMPERATURE COMPONENTS.. ............................ 101

ATTENDEES ................................................................. 103

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PHOTOGRAPHS.. ............................................................. 113

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SYMPOSIUM ON HIGH-TEMPERATURE WELL-LOGGING INSTRUMENTATION

Los Alamos National Laboratory Los Alamos, NM 87545 November 13- 14, 1985

Compi 1 ed by

Ber t R. Dennis

ABSTRACT

The E a r t h Science I n s t r u m e n t a t i o n Group a t t h e Los Alamos National Laboratory i s developing borehole 1 egging instrumentation t h a t can withstand downhole temperatures i n excess of 300°C and pressures greater than 103 MPa (15 000 p s i 1

The group was formed i n 1973 t o p r o v i d e geophysica l measurements supporting the Hot Dry Rock (HDR) Geothermal Pro ject a t Fenton H i l l , New Mexico. The HDR Pro ject needed high-temperature materials, components, transducers, and instrumentation f o r borehole logging too l s f o r i t s d r i l l i n g , hydraul ic f ractur ing, and acoustic fracture-mapping programs. I n some instances Los Alamos contracted w i t h p r i v a t e indust ry and other commercial organizations t o develop the equipment required f o r the operations a t Fenton H i l l . Now numerous Department o f Energy and p r i v a t e indust ry programs other than the HDR Pro ject are using t h i s equipment.

The purpose o f the symposium was t o inform in terested persons from industry, government, and u n i v e r s i t i e s o f these successful developments i n high-temperature we1 1-logging instrumentation.

Many ind i v idua ls and organizations i n the r i v a t e sector

the symposium. We deeply appreciate t h e i r support. The abstracts i n t h i s repo r t were prepared f o r presentation a t the symposi um.

and the Department of Energy contr ibuted t o t R e success o f

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WELCOME TO LOS ALAMOS

by

James E. Rannels U.S. Department o f Energy

Geothermal and Hydropower Technologies D iv i s ion Washington, DC 20585

We1 come t o the Symposi urn on H i gh-Temperature Well-Logging Instrumentation. My object ive t h i s morning i s t o provide the answers t o the fo l l ow ing two questions :

1) Why i s the Department o f Energy i n te res ted i n Hot Dry Rock technology? 2) Why should you be in terested i n the technology developed as p a r t of

t h i s program? AS John Whetten in fer red i n descr ib ing the c a p a b i l i t y o f the Los Alamos

National Laboratory, the responsi b i 1 i t i e s o f the Department o f Energy are q u i t e broad. An important p a r t o f those r e s p o n s i b i l i t i e s i s t o assume the a v a i l a b i l i t y o f a range o f energy options. We pursue those options t h a t are h igh r i s k but p o t e n t i a l l y h igh payoff. The r i s k s could be e i t h e r technical, economic, o r i n s t i t u t i o n a l . I n the case o f geothermal energy, the p o t e n t i a l resource i s huge.

The energy provided from geothermal i s p r i m a r i l y thermal o r e l e c t r i c a l This i s not a subs t i t u te f o r por tab le fue l s o r energy sources used i n chemical processes. I t can, however, be a subs t i t u te f o r imported fue l s used f o r e l e c t r i c a l production o r thermal appl icat ion.

The U.S. Geo log ica l Survey has rendered the s i z e o f t h e geothermal

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resource i n the contiguous U S . and provided the fo l lowing estimates: Hydrothermal connection systems 116 000 quads Geopressured-geothermal resource 113 000 quads (thermal 1

67 000 quads (methane) Hot Dry Rock resource 430 000 quads Magma energy resource 530 000 quads

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Energy consumption i n the U,S, l a s t year was approximately 75 quads. I n addi t ion t o being l i s t e d according t o s i re , the resource estimates are a lso l i s t e d according t o access ib i l i t y . Some o f you are sm i l i ng about magma. We have a l ready d r i l l e d i n t o a magma l a k e and shown t h a t i t i s t e c h n i c a l l y

feasible. Now we have a ser ies o f d i f f i c u l t technical issues t o resolve. Geothermal energy has several a t t r a c t i v e character is t ics . It i s broad

based, r e l a t i v e l y clean and safe, re l i ab le , and increasingly competit ive. I n addit ion, i t i s a base-load resource and requires a short lead t ime,

I n order t o show the f e a s i b i l i t y o f a number o f geothermal concepts, i t

became necessary for us t o c a l l on indust ry f o r services. When the services were no t avai lable, we worked w i t h indust ry t o develop them. Where indust ry was not interested, we developed the services here a t the Los Alamos National Laboratory, As a resul t , many components and techniques have been developed t h a t should be o f i n t e r e s t t o the service industry.

On a worldwide basis, the i n s t a l l e d geothermal e l e c t r i c a l capacity has increased a t the ra te o f 17% per year f o r the past s i x years through 1984 t o above 5000 MW(e). This i s not y e t a large market, b u t i t i s a r a p i d l y growing one. So there are two reasons why you should be in terested i n the technology:

1) Because i t i s pushing t h e s t a t e - o f - t h e - a r t , i t can enhance y o u r appl i c a t i on.

2 ) The geothermal market i s small bu t r a p i d l y growing; the resource i s huge.

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DESIGN AND MANUFACTURING CONSIDERATIONS FOR TFE-INSULATED CABLES

by

George C. Ph i l po t The Rochester Corporati on

Culpeper, VA 22701

The Rochester Corporation (TRC) has been a manufacturer o f o i l and gas logging cables for over 30 years. During t h i s time, the technology o f cable mater ia ls and design has changed t o accommodate increasing depths of

operation, varying corrosive environments, developments i n t o o l 'and equipment electronics, and increasing operating temperatures. Rochester has remained a leader by developing procedures, i nves t i ga t i ng new materials, and i n s t a l l i n g equipment t o meet these changing requirements. Toward t h i s end, the capabi 1 i t y t o produce high-temperature TFE-insulated cables has been developed. This included not only TFE processing b u t a lso i nves t i ga t i on Of

other cable components, such as the. metal 1 i c conductors, f 11 l e r s , and armor, t h a t a r e a f f e c t e d by t h e expected environments . The v a r i o u s t e c h n i c a l considerations regarding t h i s development are re1 ated i n t h i s paper.

One o f the primary considerations f o r logging cable has been the maximum temperature a t which i t must perform without s i g n i f i c a n t physical o r e l e c t r i c a l degradation (temperature r a t i n g ) . The d i e l e c t r i c mater ia l i s usua l l y the l i m i t i n g factor f o r the maximum temperature a t which a t y p i c a l logging cable can be u t i l i z e d .

Common logging cables have been o f s ing le- and 7-conductor construct ion and have provided operating temperature ranges up t o 500°F (260°C). Each of these designs has used an extruded thermoplastic mater ia l as the primary d i e l e c t r i c . Above 5OO0F, the extruded insulat ions were unacceptable due t o

mechanical failure (melting) or extreme cost and difficulty in processing.

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TFE, tetraf luoroethylene, had demonstrated the a b i l i t y t o withstand

operating temperatures above 500OF. Character ist cs o f TFE included resistance t o corrosive agents, nonflammability, f l e x i b i l i t y a t low temperatures, and s t a b i l i t y a t h igh temperatures. E l e c t r i c a l propert ies included low d i e l e c t r i c constant, low d i ss ipa t i on factor, and high volume r e s i s t i v i t y . These permitted TFE t o mechanically operate i n the expected harsh environments while maintaining e l e c t r i c a l i n t e g r i t y .

TFE can be processed by ram extrusion o r by taping around an e l e c t r i c a l

conductor. Since ram extrusion severely l i m i t e d the length o f continuous conductor t h a t could be insulated, taping was general ly the best method f o r applying the TFE.

Bare copper conductors ox id ize r a p i d l y a t elevated temperatures and must be p la ted w i th s i l v e r o r n icke l f o r protect ion dur ing exposure.

Since the mechanical requirements were i d e n t i c a l t o standard logging cable practice, a double layer o f cont rahel ica l armor was used t o provide strength, abrasion resistance, and torque balancing.

The 7/16-in., 7-conductor TFE cable, as manufactured by The Rochester Corporation, fo l lows establ ished logging cable design, w i th ce r ta in design and manufacturing d e t a i l s incorporated t o assure performance i n the expected environment. The TFE insulat ion, e l e c t r i c a l conductors , f i l l e r s , and armor have demonstrated the a b i l i t y t o operate successful ly i n 600°F geothermal wells. The cable i s expected t o perform equal ly wel l i n s i m i l a r high-temperature o i l and gas wells. GIith proper appl icat ion o f materials, h igh corrosive wel ls are w i t h i n i t s capabi l i ty .

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FM MULTIPLEX FOR ARMORED LOGGING CABLE

by

Evon L. Stephani Los A1 amos National Laboratory

Los Alamos, N M 87545

ABSTRACT

Exploration of the universe has been a major goal o f mankind since his beginning. Modern technology has allowed today's s c i en t i s t t o extend his observations t o the planets and actually measure many of the physical phenomena. Modern science has launched the instrumentation indus t ry into space, made possible by communications from rockets and sate1 7 i tes w i t h aerospace telemetry systems.

The development of aerospace telemetry has also opened new communication data links for making measurements i n deep boreholes i n the ear th 's crust . However, now a transmission line must be used since high-frequency signals will not propagate through this medi um. Further res t r ic t ions are i mposed upon we1 1-1 oggi ng transmission lines i n high-temperature boreholes. I t is possible t o extend the bandwidth and number o f data channels t o enhance measurements i n geothermal boreholes by combining aerospace telemetry techniques w i t h thermal protection systems and carefu l s e l e c t i o n o f wire l ine da ta transmission configurations.

I. INTRODUCTION The Phase I1 energy extraction system now being developed for the Hot Dry

Rock Geothermal Project has encountered bottom-hol e we1 1 bore temperatures

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exceeding 300°C and pressures exceeding 103 MPa (15 000 p s i ) . It i s imperative t h a t the geophysical parameters be monitored and the dimensions and o r i e n t a t i o n o f t h e Phase I 1 f r a c t u r e r e s e r v o i r be measured i n o r d e r t o optimize the f l u i d - f l o w and heat-transfer propert ies. The most severe l i m i t a t i o n s t o the use o f measuring equipment i n the geothermal wellbores are the high-temperature and h igh- f l u i d pressure e f f e c t s on the downhole instrumentation cable. To invest igate these l im i ta t i ons , two programs were s tar ted a t the Los Alamos National Laboratory, namely (1) the development o f a downhole mul t ip lex ing system and (2) a well- logging cable t e s t program (HDR

Pro ject Staf f , 1980).

11. MULTIPLEX SYSTEMS Several constraints had t o be considered i n the design o f the mu l t i p lex

system. Downhole power requirements, component size, shock, and heat d i ss i p a t i on were the major factors. Presently , our downhol e measurements have a wide variance i n data bandwidth, accuracy, and signal-condi t ioning requirements. D i f f e r e n t mu1 t i p l e x i n g techniques were compared. Universa l ly

accepted standards and a v a i l a b i l i t y o f components were a lso important considerations. Another major f ac to r was the large investment i n the e x i s t i n g

data acqu is i t i on equipment and associated software. It was decided t o design the downhole mul t ip lex system around standards

and components t h a t were r e a d i l y ava i l ab le f o r aerospace telemetry a p p l i c a t i o n s . T h i s approach p rov ided equipment and components t h a t a r e

governed by the standards set by the Inter-Range Instrumentation Group of the Range Commander's Council. Known general ly as " I R I G Standards," the documents se t f o r t h the performance speci f icat ions f o r telemetry equipment on m i s s i l e ranges under the j u r i s d i c t i o n o f the Department o f Defense ( I R I G Standard). Using I R I G standards ensures compa t ib i l i t y between manufacturers o f the downhol e components and surface recording equipment , as we1 1 as f u t u r e expansion and design. Manufacturers o f microminiature components f o r space appl icat ions could provide components t h a t are small i n s i ze and low i n power consumption, operate from a universal, unipolar, 28-V power supply, and can w i t h s t a n d 85°C o r h i g h e r temperatures and severe shock. The e l e c t r o n i c

equipment would be compatible w i th the thermal protect ion systems designed f o r the downhole instrument packages present ly used a t the Fenton H i l l s i t e .

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The I R I G standards cover seve ra l types of m u l t i p l e x i n g schemes and formats t h a t could be combined and would s a t i s f y a l l o f the downhole measurement requirements. Two primary mu1 t i p l e x i n g techniques f o r these appl icat ions include FM (frequency modulation) and PCM (pulse code modulation).

FM mul t ip lex ing i s the most common analog technique used i n telemetry. It has the' advantage o f greater data bandwidth and be t te r t ime co r re la t i on between channels.

PCM i s a d i g i t a l mul t ip lex technique t h a t i s more su i tab le f o r data t h a t has a lower bandwidth b u t requires b e t t e r measurement accuracy. PCM a l so r e s u l t s i n a lower signal-to-noise r a t i o since demultiplex equipment needs only t o detect the presence o r absence of a pulse and does not have t o detect amplitude or shape. The PCM system has a l a rge r data channel capacity and i s more convenient f o r d i g i t a l data processing. An optimum data transmission system can be achieved using a hybr id PCM/FM mu l t i p lex configuration.

FM mu l t i p lex data transmission i s present ly used i n the Laboratory's borehole acoustic t oo l s . The downhole t r i a x i a l geophone sonde uses three high-frequency, constant bandwidth data channels (+8 kHz) f o r the geophone outputs and fou r lower frequency data channels t o t ransmit a n c i l l a r y information, inc lud ing dewar temperature, incl inometer (sonde o r ien ta t i on ) , and the downhole power supply voltage (Fig. 1). A s im i la r system i s used i n the accelerometer sonde configured w i t h accelerometers instead o f geophones. A fourth accelerometer, posi t ioned a t 45" between the v e r t i c a l and hor izontal , '

i s used t o evaluate the signal coupling from the borehole t o the too l and uses a fourth high-frequency channel. The FM mu l t i p lex system i s a lso used i n the Laboratory's crosswell acousti cat receiver. The piezoel e c t r i c receiver has a

ad dynamic range, which i s separated i n t o fou r data channels w i t h

d i f f e r e n t gain set t ings. g the FM mu l t i p lex technology has increased the signal-to-noise r a t i o very i f i c a n t l y and has improved data bandwidth since o n l y t h e s u b c a r r i e r s mu d e t e c t e d a t t h e sur face and t h e r o l l - o f f

cha rac te r i s t i cs o f the logging cables not a f fec t data response.

111. WIRELINE TRANSMISSION LINK The "standard," wel l -logging, armored w i r e l i n e presents the greatest

l i m i t a t i o n t o data transmission from the downhole instrumentation t o the surface acqu is i t i on and display equipment. The armored cable used a t the

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DO WNHOLE INSTRUMENT SYSTEM

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lRlG CBW CHANNELS CHANNEL CENTER NUMBER FREOUENCY BANDwDTn

7C - WkHz f 8kHz

11C - 96kHZ f BkHz

1% - 128kHZ f BkHz - l6okHz B ~ H ~

1A - lBkH2 k 2kHz

2A - 24kHz f 2kHz

- 32 kHz 5 ZkHz

4A - 40kHz ZkHz

Fig. 1. FM mul t ip lex system for use w i t h the downhole geophone acoustic detectors.

Fenton H i 11 Test Si t e conforms to the standard 7-conductor configuration used i n the well-logging service industry. The conductor insulation determines t o a large extent the transmission characterist ics of the cable. For operations i n geothermal environments, i t is necessary t o have an insulation material w i t h excel lent high-temperature e lectr ical properties, good mechanical properties, and h i g h resistance t o geothermal borehole f l u i d s . The d i e l ec t r i c constant between conductors should be less than 3.0 and the dissipation factor a t 1.0 MHz should be less than 0.001.

The armored instrument cable used for logging the geothermal wellbores a t the HDR Fenton Hill s i t e i s a 7-conductor TFE-insulated core w i t h a galvanized Plow Steel torque-balanced armor package. The cable i s ~120 000 f t i n length

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w i t h No. 19 AWG nickel-plated copper conductors. The n i cke l p l a t i n g i s used t o deter hydrogen s u l f i d e embritt lement o f the copper. The conductors have a dc r e s i s t a n c e o f 9.2 z/lOOO f t a t ambient temperature. The capaci tance

between conductors i s about h a l f t h a t o f the other i nsu la t i on materials. A ma jo r concern f o r t r a n s m i s s i o n of h igh-frequency s i g n a l s ove r t h e

7-conductor armored logging cable i s the at tenuat ion o f the transverse electromagnetic waves (TEM) i n the p r i n c i p a l mode o f propagation. The losses associated w i th the logging cable are comparable t o the Lecher pa ra l l e l -w i re

transmission 1 ine. The Lecher-type wire1 i n e has serious l i m i t a t i o n s a t h igh frequency as f a r as losses are concerned. A coaxial transmission l i n e i s f a r superior t o the p a r a l l e l w i re and i s prefer red a t higher frequencies,but i t i s

no t y e t avai lab le w i th the TFE Teflon mater ia ls (HDR Program Staf f , 1981). Attenuation can be p r i m a r i l y a t t r i b u t e d t o the fo l l ow ing losses:

conductor losses o r sk in e f fec t , d i e l e c t r i c losses, and hysteresis losses. These losses are absorptive by nature, which means they d iss ipate energy. Mismatch losses and losses due t o rad ia t i on r e f l e c t and guide energy away from t h e t r a n s m i s s i o n l i n e . It i s v e r y d i f f i c u l t t o match impedance i n t h e 7-conductor cable since both the dc resistance and the d i e l e c t r i c constants vary s i g n i f i c a n t l y w i t h temperature whi le logging geothermal boreholes. A t the higher frequencies, the sk in ef fect becomes more c r i t i c a l and the current i s r e s t r i c t e d t o t r a v e l i n only the surface l aye r of the conductor, e f fec t i ve l y reducing the e l e c t r i c a l cross-sectional area o f the conductor. For copper w i t h a conduct iv i ty o f y = 6 x 10 M d m a t a frequency o f H hertz, the sk in depth may be approximated t o 6 = 1/15 H m. For example, a t a frequency o f 1 MHz, the sk in depth i s approximately 0.067 mm (0.0026 in.) and a t the power frequency (60 Hz), the sk in depth i s about 8.5 mm. For the No.

19 AWG wi re used i n the logging cable, the diameter o f the wire i s 0.90 mm

(0.03589 in.) and a t 100 kHz, the s k i n depth i s about 0.21 mm (0.0083 in.). The n icke l p l a t i n g af fects the sk in e f f e c t s l i g h t l y because o f i t s ferromagnetic propert ies. Using the armor as p a r t o f the transmission l i n e causes much greater sk in e f f e c t losses because the r e s i s t i v l t y o f the Plow

Steel i s much higher than copper. It i s possible t o conf igure the 7-conductor cable t o optimize

high-frequency transmission and reduce the r a d i a t i o n losses. The best

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configuration would be t o connect the s i x outer conductors together and use t h e i n n e r conductor t o approximate a c o a x i a l c o n f i g u r a t i o n . The o u t e r conductors are wrapped around the inner conductor providing some, a1 though minimal , shielding. This configuration, however, leaves no conductors avai 1 ab1 e f o r other uses.

A second configuration where conductors 1 and 3 are t i e d i n p a r a l l e l f o r the r e t u r n i s present ly used as the transmission l i n e i n the Laboratory's acoustic systems f o r the FM mult ip lexed data. Conductors 2, 4, 5, and 6 are used f o r other functions.

The t h i r d conf igurat ion p a r a l l e l s conductors 2 and 6 and conductors 3 and 5. This i s the worst case response presenting complex at tenuat ion character is t ics which can be a t t r i b u t e d t o induced EMFs i n adjacent conductors producing complicated phase s h i f t s coupled w i t h the other l oss modes. A diagram o f the conductor configuration and r e s u l t i n g frequency response i s shown i n Fig. 2.

I V . PRESENT AND FUTURE APPLICATIONS

FM mul t ip lex data transmission now used i n the Laboratory's borehole acoustic systems i s we1 1 w i t h i n the operating cha rac te r i s t i c o f the 7-conductor cable. The highest frequency o f i n t e r e s t i s 168 kHz ( I R I G Channel 19C 160 k H t k8 kHz), which i s wel l w i t h i n the detectable range o f the surface

data acquis i t ion system. The FM mul t ip lex ing was incorporated i n the acoustic t o o l s because o f the high-frequency data r a t e required. A PCM mu l t i p lex system w i l l be used i n a new spinner/ temperature/p.ressure sonde. The PCM

d i g i t a l format w i l l be t ransmit ted on a FM subcarr ier t o improve signal -to-noise r a t i o . A combination o f PCM f o r d i r e c t d i g i t a l formatt ing

w i t h the FM subcarr ier f o r s ign i f i can t improvements i n signal-to-noise w i l l enhance the capab i l i t i es t o l o g deep boreholes i n the geothermal environments.

BIBLIOGRAPHY

1. W. E. Garne, "Conmercial Cables f o r Geothermal Logging," High Temperature Electronics and Instrumentation, Seminar Proceedings, Houston, TX, December 3-4, 1979.

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CABLE TEST : TFE 7- Conductor

Fig. 2. 'Dotted l ine is conductor 7 t o 1, 2 s 3, 4, 5, 6 paral le l . 2Dashed l ine is conductor 7 t o 1, 3 parallel . 'Solid line is conductor 2, 6 parallel -- 3, 5 paral le l .

HDR Program Staff, "Hot Dry Rock Geothermal Energy Development Program, Annual Report, Fiscal Year 1980," Los Alamos Scient i f ic Laboratory report LA-8855-HDR9 pp. 151-161.

3. HDR Program Staff , "Hot Dry Rock Geothermal Energy Development Program, Annual Report, 'Fiscal Year 1981," Los Alamos National Laboratory report LA-9287-HDRS pp. 110-118.

4. IRIG Standard 106-80 -- Telemetry Standards.

5. Wayne Kerr, "Armored Well Logging Cable for Geothermal Borehole Environments ,I1 High Temperature Electronics and Instrumentation Seminar Proceedings, Houston , TX, December 3-4, 1979. -

11//

J

1

F i )

c

M I N ERAL - I NSULATED CABLES

by

Barry W, Palmer B ICC Pyrotenax LTD

523 North Belt, Sui te 540 Houston, TX 77060

The basic construct ion o f mineral - insulated cables i s a metal jacket encasing t i g h t l y compacted magnesium oxide powder, which i n t u r n surrounds one o r more conductors.

This cable was developed near ly 100 years ago but not manufactured u n t i l 1937. The use o f mineral- insulated cable may be considered a new app l i ca t i on fo r a well-proven product. nax, now 49 years l a t e r , i s the l a rges t manufacturer o f mineral- insulated cables i n the world.

Transducer l ead -ou t cables, w i t h s t a i n l e s s tee1 j a c k e t s and copper conductors, have been avai lab le f o r some time b u t i

I n 1982/83 we deve ped and i n s t a l l e d a p r o d u c t i o n u n i t t o produce continuous cable i n lengths o f up t o 30 000 ft, This launche he s l i cksender range; the range was fu r the r extended by armoring the cables, thus o f f e r i n g a high-temperature logging cable.

B I C C Pyr

e l a t i v e l y short lengths.

The manufacturing process t o produce such a cable i s ca l l ed w e l d - f i l l draw o r conform.

, Slicksender ca avai lable i n 1-4 conductors, the standard jacket being 316L sta in less steel . Type K conductors,

Long-length thermocouples are a lso avai lab le w i t h

By armoring these bles, we are able t o o f fe r a range o f high-temperature logging cables w i t h e i t h e r galvanized o r s ta in less s tee l armor wires and f in ished sizes o f 7/32 o r 5116-in.; minimum sheave diameters f o r these are 12 and 15 in. , respectively.

13

Cabl e diameter Cabl e weight Breaking strength Elongation ( for every 1000 f t w i t h 224-1b load) Minimum sheave diameter Maximum continuous operati ng tempera ture--gal vani zed Maximum continuous operating temperature --stainless steel vo I tage rat ing DC conductor resistance Armor+ jacket resistance Capacitance Cable reference

TABLE I

WIRELINE CABLESa

Single Conductor 18AWG

7/32-i n . D i am

7/32 i n . 95 1 bs/1000 f t 4200 l b s 12 i n .

12 i n . 900°F

1100°F

600 Vdc 6.4 ohms/1000 f t 4.1 ohms/1000 f t 118 pF/ft MTCAlT307.32

Single Conductor 18AWG

5/16-i n. Diam

5/16 i n . 200 lbs/1000 f t 10 000 l b s 15 i n .

15 i n . 900°F

1100°F

600 Vdc 6.4 ohms/1000 f t 1.7 ohms/1000 f t 118 pF/ft MlCAlT305.16

aOther sizes of single, t w i n , and four core are available upon request.

These logging cables have been successfully used i n Japan for temperatures up to 640°F and are par t of a "super high-temperature geothermal we1 1 1 oggi ng system" devel oped by Japan Petroleum Company.

MP35N -- S t r i p i s n o t a v a i l a b l e a t th i s time i n sizes required t o manufacture cable. Annealing temperatures are too h i g h for copper, therefore nickel would have t o be used. Conductor resistance for 4-conductor cable is est imated a t 325/375 ohms/1000 f t . If cab le s ize i s increased t o 6 m m , conductor resistance would drop t o 75 ohms/1000 f t .

Manufacturing tr ials are needed t o determine i f modifications are necessary t o our existing p l a n t . We would also need assurance from the trade t h a t such a cable i s required.

Advantages of slicksender cables include the following: 1) withstand temperatures up t o 800°C for the thermocouple and 600°C for

2) withs tand pressures i n excess of 45 000 psi; 3) corrosion resistant stainless s teel 316L jacket o r other materials

the w i re1 i ne ;

upon request;

14

1

* F

t

4 ) available up to 30 000 f t in length; 5 ) unique construction assures complete performance rel iabi l i ty and

resistance to mechanical damage; 6) cable available w i t h 1, 2, or 4 conductors; 7 ) small size, less than 1/8 i n . over jacket; 8 ) available w i t h either stainless steel or galvanized armor in standard

9 ) suitable for geothermal wells. diameters of 7/32 and 5/16 in.; and

I

I

MATERIALS TESTING/ARMORED LOGGING CABLE

by

Tracy A. Grant Los Alamos National Laboratory

Los Alamos, NM 87545

This paper stresses the importance o f t e s t i n g and analyzing mater ia ls before and a f t e r they have been used, especia l ly i n geothermal wells.

Mater ia ls have been tested a t the Los Alamos National Laboratory n o t on ly f o r the Hot Dry Rock Geothermal Energy Pro ject a t Fenton H i l l but a lso because logging other wel ls i s sometimes required. Since the environment a t these other locat ions i s usual ly more corrosive than the environment a t the Fenton H i l l S i t e (FHS), i t i s important t o study every possible parameter t h a t may be encountered.

The electromechanical armored logging cable i s one o f the most v i t a l

t o o l s i n any logging operation. The three main components o f the cable - the o u t e r cab le armor, t h e i n s u l a t i o n , and the e l e c t r i c a l p r o p e r t i e s o f t h e conductors - are used as prime examples for t e s t s and analysis. Also, two d i f f e ren t systems, used f o r conducting tes ts on the armored logging cable and

i t s components, are presented . These systems are expl a i nqd f i r s t . The f i r s t system consists o f a 0.5-a pressure vessel made o f Hastel loy

C-276 able t o operate a t a temperature d f 200°C w i t h a pressure u p s i Also, a load frame, load t ra in , and the d r i ve mechanism are used t o apply a constant s t r a i n r a t e t o the specimen i n the vessel whi le i t i s exposed t o a simulated geothermal f l u i d (see Fig. 1). I n t h i s case, s ing le wire strands o f various metal a l l oys t h a t could be p o t e n t i a l candidates fo r the o u t e r cab le armor w i l l be tes ted . Constant s t r a i n - r a t e t i m e - t o - f a i l u r e

r e s u l t s , w i l l be obtained as we l l as the e f fec ts o f ce r ta in key species i n the f l u i d o f a c r i t i c a l stress l eve l o f the a l loy. Simi lar r e s u l t s may also be

17

c

TEMPERATURE LIMIT - 2000C PRESSURE LIMIT - 2000 psi HASTELLOY C-276.0.5 LITER

LOAD FRAME

ENVIRONMENT CHAMBER (PRESSURE VESSEL)

DRIVE MECHANISM

Fig. 1. Constant extension r a t e tester .

obtained when standard "dog-bone" samples o f metal a l l oys are placed i n the

vessel and used t o determine mater ia ls select ions f o r downhole tools. The second system i s a high-pressure/high-temperature (3000 psi/350°C)

autoclave used t o t e s t a whole section o f logging cable (see Fig. 2) . The cable t e s t f a c i l i t y i s avai lable f o r t es t i ng the e f fec ts o f neutral-to-high pH

geothermal f l u i d s on the outer cable armor, the i nsu la t i on propert ies a t h igh temperatures, and the e l e c t r i c a l p r o p e r t i e s o f t he cable. I n u s i n g t h i s f a c i l i t y , the e n t i r e cable i s placed under a constant s t a t i c stress i n the vessel and tested f o r the various propert ies.

Several mater ia ls tes ts have been conducted on the armored logging cable and i t s components. One example o f t e s t i n g the cable re la tes t o i t s ove ra l l strength. The cable head i s the component a t which the connection between the downhole instrument package and the cable br ing ing informat ion t o the surface

i s made. When t h e cab le i s a t tached t o a downhole i n s t r u m e n t and t h a t instrument i s lodged i n the well , i t i s important t o be able t o p u l l the cable

o u t o f a cone basket which i s i n the cablehead so the e n t i r e cable won't break

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Feedthrough

Temperature Limit - 3!WC

Pressure Limit - 3000 psi

Overall Length - 23'8"

Maximum Dia. - 4.00"

Potting Port Feedthrough

Fig. 2. Cable t e s t autoclave.

and get l o s t downhole. Several cables were headed and pu l l - t es ted t o obta in a pu l l -out load t h a t would be dependable everytime. I n t e s t i n g the cable t h a t

i s f requent ly used a t the FHS, a standard conf igurat ion was devised. It was found t h a t by terminat ing 11 o f the 22 outer wire strands (every other strand)

over the cone i n the cone basket and using a c e r t a i n s ize o f cone and cone basket everytime, a repeatable load o f 4000 l b s could be placed on the cable

before the 11 strands would break and release the cable. The next example i s presented t o emphasize the importance o f t e s t i n g

mater ia ls t o avoid surpr ise complications. I n t h i s case, a high-temperature e l e c t r i c a l connector, ' which i s used t o make t h e connect ion between t h e downhole instrument package and the logging cable, was placed i n d i s t i l l e d water, heated, and pressurized. The t e s t was' conducted i n i t i a l l y t o study the e f f e c t s o f t h i s environment on an elastomer piece o f the connector which i s housed by metal A f te r approximately 2 h of exposure a t 220°C, the elastomer d i d show signs o f decay. However, the su rp r i s ing r e s u l t was t h a t the outer meta l housing, which was thought t o be s t a i n l e s s s t e e l , became s l i g h t l y

corroded i n the form o f p i t t i n g . Since t h i s i s unusual f o r s ta in less s tee l i n d i s t i l l e d water, a simple q u a l i t a t i v e analysis was performed, on the metal which showed i t t o be aluminum. I n t h i s s i tuat ion, i f the aluminum connector had been used i n an a l ka l i ne environment f o r example, i t would have been

r a p i d l y attacked and the e l e c t r i c a l connection l o s t . One l a s t example o f a n a l y z i n g m a t e r i a l s a f t e r t hey have been used

involves the i nsu la t i on used on the conductors i n the cable. Three types of

19

i nsul a t i on were analyzed usi ng a Scanni ng E l ectron Microscope to determi ne the mode of wear t o each. Each of these materials was used extensively on logging cables mainly a t the FHS. The trade names o f these three fluoroplastics are polytetrafluoroethylene (PTFE or TFE), polyfl uoroal koxy (PFA) , and ethylene tetrafluoroethylene (ETFE or Tefzel 1. A1 1 are Teflons made by DuPont.

The experiences w i t h each of these materials a t the MS agreed f a i r l y closely w i t h the published data. A l l properties of the Tefzel insulation functioned properly up t o around 200°C; however, above tha t temperature the electr ical properties began t o f a i l . The PFA cable was exposed t o temperatures as h i g h a s 320"C, b u t i t was not iced t h a t the mechanical properties began to f a i l around 260°C. The TFE-insulated cable has proved to withstand the Fenton Hill environment very well. I t has been used extensively a t temperatures as h i g h as 320°C w i t h no signs of e lectr ical or mechanical degradation.

Physical wear t o each of the insulating materials was examined extensively. I t was found tha t the TFE and PFA materials had grooves formed into them which were caused by the force of the outer cable armor. All of the grooves were f a i r ly uniform w i t h the shape and diameters of the inner layer of armor. The Tefzel insulation showed no signs of physical wear. Also, cross- sectional views of each conductor core indicated tha t the insulating material S

molded to the conductor fibers. With this type of materials analysis, the mode o f wear to each of the

insulation types was examined. If the deformation were t o continue as i t has i n the TFE and PFA cables, the conductors would eventually get so close to the surface of the insulation t h a t they would begin t o touch each other or the outer cable armor and short-out. T h i s type of physical deformation is not l ikely t o occur t o the Tefzel insulation; however, i t will not withstand the h igher temperatures.

20

t

HIGH-TEMPERATURE CABLEHEAD

by

Jose U. Cruz Los Alamos National Laboratory

Los Alamos, NM 87545

Engineers a t the Los Alamos National Laboratory have designed and s u c c e s s f u l l y operated a cablehead t h a t can f u n c t i o n i n temperatures and pressures greater than 320°C (608°F) and 103 MPa (15 000 ps i ) . The cablehead

assembly provides a cable-to-sonde electromechanical coup1 i n g device, which protects the e l e c t r i c a l conductors from the high-pressure/high-temperature environment. It establ ishes a t r a n s i t i o n area from the downhole f l u i d , high- pressure environment t o a dry, low-pressure instrument chamber. The cablehead assembly i s a protected area f o r s p l i c i n g the cable conductor ends t o the high-temperature bulkhead.

Should the instrument sonde become lodged i n the wellbore, the cablehead i s designed t o a l low separation of the sonde and cable. The f i s h i n g b e l l housing then provides a p o s i t i v e gr ipp ing area f o r overshot f i s h i n g t o o l s f o r r e t r i e v a l from the borehole.

I. INTRODUCTION

The major funct ion o f the Hot Dry Rock (HDR) engineering group i s t o character ize the underground heat exchange system. The p r o j e c t engineers found t h a t the most useful and accurate method o f mapping the reservo i r i s t o lower sens i t i ve t o o l s i n t o the boreholes. These too l s measure the physical p r o p e r t i e s o f t h e r e s e r v o i r and t r a n s m i t data t o s u r f a c e r e c o r d i n g and computation f a c i l i t i e s v i a the high-temperature mu1 t iconductor armored cable.

The HDR bo reho le environment i s harsh: a l l downhole equipment must s u r v i v e exposure t o 320°C (608°F) and 103 MPa (15 000 p s i ) . Since most

21

commerc ia l ly a v a i l a b l e t o o l s a re n o t designed f o r extended use i n such

high-temperature pressurized environments, the Los Alamos engineers had t o modify ex i s t i ng too l s o r develop new ones t h a t could operate under severe condi ti ons .

The success o f any too l used i n the HDR system depends p a r t i a l l y on the q u a l i t y o f the e l e c t r i c a l and mechanical connections between the t o o l and the cable. Should t h e cable conductors come i n c o n t a c t w i t h t h e f l u i d , t h e e l e c t r i c a l connections break down and the t o o l 's a b i l i t y t o c o l l e c t accurate data deteriorates. To provide a q u a l i t y connection, the HDR engineering s t a f f

had t o design a cablehead assembly t h a t could operate i n the harsh downhole geothermal environment.

11. FUNCTIONS OF THE HIGH-TEMPERATURE CABLEHEAD

The primary funct ion of the high-temperature cablehead i s t o provide a waterproof environment f o r the electromechanical coup1 i n g device between the t o o l and the armored cable. Other funct ions o f the cablehead are

1) t o estab l ish a t r a n s i t i o n area from the downhole f l u i d high-pressure/high-temperature environment t o a low-pressure environment i n the tool ,

2) t o provide a protected area f o r s p l i c i n g the cable conductor ends t o the high-pressure bulkhead,

3) t o al low f o r a quick downhole separation between the too l and the cable should the t o o l become stuck, and

4 ) t o p r o v i d e a g r i p p i n g groove ( f o r commercial overshot t o o l s ) f o r f i s h i n g the stuck too l out o f the borehole.

111. THE LOS ALAMOS DESIGN

The Los Alamos-designed cablehead i s a f o u r - p i e c e assembly. It i s comprised o f a cable re ta in ing section, cab1 e packoff/breakaway section, spl i c i ng cav i t y , and high-pressure bul khead housi ng . The i n t e r i o r components are designed so as t o minimize the amount o f t ime required t o assemble, clean, o r replace when making repairs.

I V . SECURING THE CABLE It i s important t h a t the cable i s held t i g h t l y w i t h i n the cablehead so

22

1

I 1

i ~

, , i I j I

i

I

1 i j

i 1

t h a t i t does no t t w i s t f r e e from i t s e l e c t r i c a l and mechanical connections w i t h the tool.

To prevent the cable from r o t a t i n g w i t h i n the subassemblies, an EPDM grommet (Compound Y267) made by L'Garde, Inc., i s f i t t e d around the cable where the cable re ta ine r and the cable packoff/breakaway subassemblies j o in . A t the lower end o f the cable packoff/breakaway subassemblies, the cable armor i s terminated. The armor i s wedged i n t o a cone basket w i th a cone placed between the outer and inner armor.

The too l i s j o in ted t o the cablehead by a swivel nut. This al lows the

t o o l t o be connected t o the cablehead wi thout r o t a t i n g o r c o i l i n g the wires v i a the mu1 t i p i n bayonet e l e c t r i c a l connector. The bayonet connector a lso

al lows f o r a quick change o f tools.

I I

V. WATERPROOFING THE CABLEHEAD Water i s most l i k e l y t o seep i n t o the cablehead through the top o f the

r e t a i n i n g subassembly housing. To prevent leaks once the cable has been attached, a high-density s i l i c o n o i l i s used t o prevent water from seeping i n t o the cable conductors and destroying the e l e c t r i c a l connections . A Krytox o i l i s poured i n t o the packoff/breakaway subassembly and the s p l i c i n g c a v i t y

through i n j e c t i o n ports. L iqu id Krytox has a spec i f i c g rav i t y o f 1.5. Any

moisture t h a t i s i n the v i c i n i t y o f the conductors w i l l f l o a t uphole and away from the e l e c t r i c a l connections. The o i l i n j e c t i o n po r t s are sealed off w i t h a s ta in less steel pipe plug.

Water i s prevented from seeping i n t o t h e cab le p a c k o f f c a v i t y by an- elastomer grommet. The grommet w i l l a lso thermal ly expand downhole.

Parker O-rings, using the L'Garde EPDM compound, are used t o prevent leaks a t a l l the subassembly junctures and around each o f the feedthroughs i n the high-pressure bulkhead. The bayonet e l e c t r i c a l connector between the too l

and the cablehead i s sealed by a Parker O-ring and Bal-Seal.

V I . THE CABLEHEAD BREAKAWAY SYSTEM

Should the too l become wedged downhol e, the cablehead's breakaway design al lows f o r the r e t r i e v a l o f the e n t i r e length o f cable and the subsequent f i sh ing o f the stuck too l .

23

The breakaway des ign uses the method where o n l y t h e o u t e r armor i s secured t o the cablehead cone basket assembly. The inner armor i s no t secured i n the cablehead. This method o f terminat ing the armor would a l low the cable t o p u l l ou t a t 4000 l b s from the cablehead, leaving the e n t i r e head assembly attached t o the instrument sonde. The cone basket i s submerged i n o i l and i s no t exposed t o corrosive f 1 uids , preserving repeatabi 1 i t y o f breakaway p u l l forces .

24

SMOOTHWALL LOGGING CABLES

Arthur Hal penny Halpen Engineering, InC.

645 Persons Street East Aurora, NY 14052

The purpose o f t h i s paper i s t o present various design a l te rna t i ves i n the general f i e l d o f downhole logging and instrumentation cables, p a r t i c u l a r l y

those t h a t are subjected t o high temperatures and corrosive environments. The centra l theme t h a t runs through the presentation i s the c a p a b i l i t y o f covering d i f f e ren t configurations o f cables w i th smoothwall s ta in less steel sheaths. This technique i s a natural progression from many years o f manufacturing mineral -insulated, stainless-steel , sheathed-heater cable, although the

lengths involved are considerably greater than the r e l a t i v e l y shor t runs Of

cable used i n pipe and vessel temperature maintenance. The d i f f e r e n t cable designs a l l e x h i b i t c e r t a i n character is t ics :

high-corrosion resistance, high-temperature capab i l i t y , high-compressive strength, long lengths, self-supporting, smoothwall, and hermet ical ly sealed sheathing.

The sheath m a t e r i a l can be v a r i e d t o o b t a i n t h e maximum c o r r o s i o n resistance. The sheath thickness can be increased t o provide greater t e n s i l e strength.

The sheath can be placed over polymer-insulated conductors as wel l as

mineral insulated. It can a lso be placed over counterhel ica l ly wound w i re armor.

Engineers involved i n downhole invest igat ions should g ive consideration t o the many design a l te rna t i ves provided by the "oversheathing" system and enjoy 1 t s economic advantages.

' I

MATERIALS ISSUES I N HIGH-TEMPERATURE ELECTRONICS

Materials, individua

Randal 1 K . K i r sc hman P.O. Box 391716

Mountain View, CA 94039

l y and i n combination, p!dy a key r c ? i n determi n i ng the elevated-temperature character1 s t i cs and operating temperature l i m i t s o f e lec t ron i c devices and systems. Achieving adequate performance i s a challenge because most mater ia ls propert ies decl ine as temperature i s increased f o r e lec t ron i c appl icat ions. Furthermore, degradation mechanisms accelerate so t h a t l i f e t i m e i s inverse ly re la ted t o temperature. Present c a p a b i l i t i e s are t y p i c a l l y i n the 200'c t o 300°C-range f o r hundreds o f hours. The fundamental l i m i t a t i o n f o r semiconductor-based e lect ron ics ar ises from the physics o f the semiconductor mater ia l i t s e l f . I n theory, s i l i c o n devices can be used t o about 300"C, gal l ium arsenide devices could be used t o 450"C, and other semi conductor mater i a1 s , a1 though present ly unavai 1 ab1 e , coul d be used t o temperatures as h i g h as 1000°C. For most semiconductor dev ices and e lec t ron i c systems, however, the p r a c t i c a l l i m i t i s less than t h i s and i s determined by assoc ia ted techno1 ogy. I n some ins tances t h i s r e 1 a t e s t o

inherent proper t ies o f a s ing le mater ia l , whi le i n others i t i s determined by i n te rac t i ons when d i f f e r e n t mater ia ls are interfaced. Examples include the

fol lowing: on-chip m e t a l l i z a t i o n systems; mater ia ls used f o r interconnecting, mounting, and packaging semiconductor chips and other components; and mater ia ls f o r conductive, res i s t i ve , and d i e l e c t r i c functions i n hybr id c i r c u i t s . Inorganic materials, i .e. , ceramics, glasses, and metals, are r e l i a b l e standbys; the use o f systems invo lv ing polymers much above 200°C i s more d i f f i c u l t , although progress i s being made f o r t h i s class o f materials.

I n conclusion, through jud ic ious se lect ion and evaluation, present ly avai lab le

27

materials, materials systems, and technologies are already meeting many o f the needs o f high-temperature electronics, and extension o f the temperature range and lifetime i s possible through further research and development.

2%

BURR-BROWN WIDE-TEMPERATURE PRODUCTS

by

George L. H i l l Burr-Brown Research Corporati on

6730 S. Tucson Blvd Tucson, AZ 85706

I n the l a t e ~O'S, Burr-Brown recognized two p o t e n t i a l l y large markets for data acquis i t ion components t h a t could withstand temperatures wel l above the normal maximum of 125°C (which had been defined by the m i l j t a r y ) : instrumentation f o r downhole o i l wel l logging and e lect ron ics f o r motor and engine monitoring and contro l . A t the same time, improvements i n hybr id technologies, CMOS l o g i c a v a i l a b i l i t y , and l i n e a r IC's based on d i e l e c t r i c

i s o l a t i o n made i t possible t o design standard data acqu is i t i on components for operation a t up t o 200°C w i th reasonable y ie lds. The perceived markets and

, improving technologies l e d Burr-Brown t o introduce a ser ies Of

h i gh-temperatu : a complete analog-to-digi t a l converter ( ADClOHT) , a re la ted d i g i t a l -to-analog converter (DACIOHT) , and two complementary op-amps (OPA11HT and OPA12HT).

The market f o r elec onics f o r engine/motor monitoring and regulat ion has never taken o f f , he decl ine i n the i n t e n s i t y o f o i l exp lorat ion i n the e a r l y 80's has red the growth o f demand i n t h a t area, so t h a t the rea l market f o r high-te s i n the f i r s t h a l f o f the 80's has been stable, a t best, a t a 1 r than our expectations, Only w i t h i n the past year have the market cond i t i o proved t o the p o i n t t h a t Burr-Brown and the other f i rms supplying wide nge products are ser ious ly

But the intervening "down" years have not been a time o f no progress. A t Burr-Brown, our ADClDHT sales have remained strong. This ind icates a continuing market desire f o r integrated solut ions t h a t reduce design

i nves t i ng i n major new product dev S .

29

d i f f i c u l t y by reducing board s ize as compared w i t h an A-to-0 b u i l t ou t Of

several packages and a lso reduce compa t ib i l i t y problems f o r the designer. Since

Burr-Brown t e s t s and guarantees performance o f the complete converter, the designer i s re l ieved o f r e s p o n s i b i l i t y f o r making sure. the i nd i v idua l subcomponents work together even a t 200°C. I n fact, Burr-Brown has probably made the most progress i n the area o f t e s t i n g converters a t h igh temperatures. Careful combination o f a Thermostream System from Temptronic Corporation wi th our standard production LTX t e s t systems y i e l d s reproducible t e s t r e s u l t s f o r a wide v a r i e t y o f parameters. This compares very favorably wi th e a r l i e r d r i f t oven systems t h a t were prone t o frequent breakdown and inconsistent data. I n fact , f o r e a r l i e r d r i f t systems we were forced t o r e l y on expensive custom p r i n t e d c i r c u i t boards designed t o operate a t 200°C t h a t proved t o be regular problem sources i n production.

A t the same time, hybr id assembly methods f o r components destined f o r wide-temperature excursions have improved s i g n i f i c a n t l y over the l a s t f i v e years. The combined e f fec t o f these advances i s t h a t 200°C products can be produced under more standard manufacturing condi t ions , which u l t i m a t e l y means more r e l i a b l e par ts del ivered on t ime (more of ten) and a t stable pr ices. When volumes f i n a l l y do s t a r t t o increase, what we have learned should a lso help pr ices f o l l o w the downward trend more common i n electronics.

For a number o f reasons, i nc lud ing the requirements o f the high-temperature markets, Burr-Brown has a1 so used the l a s t several years t o b u i l d up expert ise i n several technologies. The most v i s i b l e o f these i s d i e l e c t r i c i s o l a t i o n ( D I ) , which has strong performance advantages over the

more standard, and less cost ly, j unc t i on i s o l a t i o n processes. Burr-Brown has already introduced a va r ie t y o f l i n e a r IC's using D I , and several converter products are on the drawing boards a t the moment. All o f these are candidates for gradeouts, o r modifications, f o r 2OO'C operation. Equally important f o r b u i l d i n g more complete c i r c u i t s and converters i s our growing experience w i t h CMOS designs. The low-power advantages o f CMOS t r a n s l a t e d i r e c t l y i n t o re1 i a b l e performance a t higher ambient temperatures since the d e l t a from chip temperature t o ambient i s reduced by the lower consumption. Burr-Brown w i l l be using CMOS t o make converters t h a t are increasingly "user- f r iendly" by adding increased l o g i c t o hybr id converters. A t the same time, we are soon going t o introduce our f i r s t CMOS D-to-A IC's and p lan t o r a p i d l y pursue wide-temperature versions o f these.

30

c

While i t i s premature t o discuss in t roduct ion schedules o r spec i f icat ions f o r s p e c i f i c products , i t i s n o t t o o soon t o o u t l i n e t h e types o f wide- temperature products we are focusing on over the next year o r so. Burr-Brown's f i r s t CMOS MDAC ( m u l t i p l y i n g D-to-A c o n v e r t e r ) w i l l be t h e indust ry standard 7541A, and we expect t o have a wide-temperature range grade

o f t h i s device. We a lso bel ieve the t ime i s r i g h t f o r the next generation of 200°C A-to-D converters w i th fas te r conversion times ( t o a l low more data t o be co l lected) and probably w i th more l o g i c f o r i n t e r f a c i n g w i t h microprocessors. We fntend t o develop something l i k e our ADC574A f o r these requirements. We

a lso recognize a need f o r mul t ip lexer and sample/hold c i r c u i t s , especia l ly i n engine/motor where i n p u t s i g n a l s may change ve ry r a p i d l y . The s p e c i f i c

p roduc ts w i l l be d e f i n e d i n e a r l y 1986, based on t h e r e s u l t s o f s e v e r a l development pro jects now under way.

H IGH-TEMPERATURE MICROELECTRONICS

by

Tom Elsby White Techno1 ogy , Inc. 4246 E. Wood Street

Phoenix, AZ 85040

White Technology, Inc., has been involved i n the design and development o f hybr id m ic roc i r cu i t s f o r high-temperature appl icat ions f o r over ten years, extending back t o i t s previous name o f Custom Devices.

Many m a t e r i a l s have been researched w i t h r e s p e c t t o t h e i r use and re1 i abi 1 i t y a t temperatures exceed1 ng 200OC. Polymers , g l asses , cerami cs , and t h i c k f i l m compositions were selected from these evaluations t o provide a

mater ia l technology base f o r high-temperature hybr id development and production.

Semiconductor device evaluations a lso played a s i g n i f i c a n t p a r t i n White's success i n high-temperature hybr id technology. Combining r e l i a b l e device select ions w i th mater ia ls capable o f performing a t h igh temperatures along w i t h the unique c i r c u i t design expert ise, White Technology, Inc., has come up w i th a standard product 1 i n e o f regulators , osci 11 ators , amp1 i f i e r s , references, microprocessor modules, memory modules, and other per ipheral devices fo r 200°C applications.

The c r i t e r i a f o r new standard product designs are as fol lows: 1) must have a minimum 1000-h usable l i f e t i m e a t 200°C; 2) must pass 225'C t e s t i n g i n development t o guarantee 200°C performance; 3) must be capable o f meeting mechanical shock, v ibrat ion, and thermal

shock condit ions normally encountered i n downhole measurement too l s (screened t o MIL-STD methods 1 ;

4) must provide a usable bu i l d ing block f o r high-temperature t o o l

33

a

. designers ( t h i s provides the access t o years o f technology a t a nominal cost and el iminates the need t o "reinvent the wheel"); and

5) must provide a cost competit ive approach t o the user. For the past two years, White Technology, Inc., has been developing a

microprocessor system f o r downhole appl icat ions. While not l i m i t e d t o t h i s use, i t provides a very powerful mechanism t o c o l l e c t and process data a t extreme environmental conditions.

The current system i s based on a 80685 processor w i th a clock o s c i l l a t o r , memory, and mux, a l l on board i n a 40-pin hybr id package. Memory add-ons i n 16 K-byte increments are avai lable (RAM'S) as are 2 K x 8 EEPROM modules, which can be r e l i a b l y w r i t t e n t o a t 150°C and read without e r r o r a t 200OC. A

dual para1 1 e l /dual s e r i a1 p o r t module gives I O expandabi 1 i t y where required. I n development are a 16-b i t processor module, VF converters, A-D

converters, t iming modules, and DA converters, a l l f o r 200°C performance. Besides our standard product developments, White Technology, Inc.,

provides many custom designs b u i l t t o customer speci f icat ions. Our experience, technology, and intense i n t e r e s t i n 200°C-circui t challenges have made White Technology, Inc., a r e l i a b l e source f o r solv ing high-temperature problems.

34

NEW CAPABILITIES I N PYROFLASKS

R. W. Blanton Vacuum Bar r i e r Corporati on

4 Barten Lane Woburn, MA 01801

PY ROFLASKS r e f e r t o h i g h-temperature dewars used f o r thermal p ro tec t ion o f sens i t i ve downhole equipment. A1 though f l a s k fab r i ca t i on techniques have been wel l established f o r many years, Vacuum Bar r i e r has continued t o make state-of- the-art advances. To b e t t e r understand these, basic f l a s k construct ion and operating p r inc ip les are f i r s t reviewed.

Shown i n F ig . 1 i s a c ross s e c t i o n o f a t y p i c a l PYROFLASK assembly, comprised o f two concentric shel ls, welded vacuum t i g h t a t each end. The annular space surrounding the inner she l l i s pumped out through the evacuation tube, which i s subsequently pinched, o r co ld welded, creat ing a permanent high-vacuum seal. Also, i n t h i s annular space, Vacuum Bar r i e r u t i l i z e s a mu l t i l aye r i nsu la t i on consis t ing o f a l te rna te layers o f aluminum and glass f ibers . The combination o f h igh vacuum and m u l t i p l e r e f l e c t i v e layers r e s u l t s i n extremely low heat loss through the wal ls o f the PYROFLASK.

Below the inner she l l i s the r a d i a l support, a high-strength, low-heat- loss structure'designed t o ho ld the inner she l l concentric w i th in the outer wh i le pe rm i t t i ng a x i a l d i f f e r e n t i a l expansion and contract ion dur ing temperature changes.:

Shown above and below the i n te rna l equipment are thermal storage mater ia ls o r "heat sinks." These can take a v a r i e t y o f forms, i.e., s o l i d metal s , 1 ow-me1 ti ng temperature a1 1 oys , o r other phase change materi a1 s , and are bas i ca l l y used t o absorb heat d iss ipated by the equipment and/or the heat leaked i n t o the f lask, thereby extending downhole time capab i l i t y .

35

Fig. 1. Cross section o f a t yp i ca l PYROFLASK assembly.

The i n s u l a t i n g stopper a t the open end of the f l a s k i s characterized by low thermal conduct iv i ty (and sometimes high heat capacity) and functions t o l i m i t heat f low i n t o the open end o f the f lask.

The overa l l heat loss o f the f l ask i s composed o f several i nd i v idua l components :

11, conduction through the i nsu la t i ng stopper, 2) conduction down the inner she l l o r neck, 3) conduction through the rad ia l support,

4) conduction and rad ia t i on through the walls, and 5 ) conduction through wires o r other connections penetrat ing i n t o the

f lask. F i g u r e 2 i s a photograph o f a p o r t i o n o f t h e VBC manu fac tu r ing area

containing the ovens i n which f l asks are evacuated a t elevated temperatures. Using r o u t i n e techniques o f t h i s "outgassing," PYROFLASKS a r e r a t e d f o r operating temperatures o f up t o 600"F, whi le upon request, special processing

36

Fig. 2. Evacuation ovens i n the VBC manufacturing area.

enables the PYROFLASKS r a t i n g t o be increased t o 850'F. The la rge capaci ty of

these ovens allows VBC t o respond rap id l y t o high-quantity requirements.

Today i t i s common t o approve downhole equipment inc lud ing PYROFLASKS for

h o s t i l e environments through shock and v ib ra t i on test ing. This has l ed Vacuum Bar r i e r t o perform shock and v i b r a t i o n tests, on some representat ive uni ts . Shown i n Fig. 3 i s a PYROFLASK on a shake table during development test ing

conducted by VBC. With r e s u l t i n g upgrades made i n the mechanical character is t ics , PYROFLASKS are now fabr icated t h a t undergo extensive shock and v i b r a t i o n tes ts w i th no thermal o r mechanical

I n the tes t i ng oven p ic tu red i n Fig. 4, each PYROFLASK receives a t l e a s t three thermal performance tes ts a f te r p inch-of f and before shipment. The t e s t

consists of pos i t ion ing a temperature sensor i ns ide the f l ask w i t h an i nsu la t i ng stopper i n the open end. The oven temperature i s then elevated and t h e i n t e r n a l temperature i s mon i to red over a p e r i o d o f f i v e hours. By

performing a ser ies o f these tests, any f l a s k w i t h a possible problem can be detected and re jected. A1 though the procedure may appear somewhat laborious,

37

i

Fig. 3. PYROFLASK on shake tab le dur ing development test ing.

i t has proved w e l l wo r thwh i l e over t h e years i n f u r n i s h i n g r e l i a b l e and cons i s ten t PY ROFLASKS .

A standard form u t i l i z e d f o r evaluat ing f l ask app l i ca t ion i s shown i n

Fig. 5. Requested are the important parameters o r const ra in ts from which we can q u i c k l y determine t h e f e a s i b i l i t y o f a f l a s k des ign and heat s i n k requirements . Typical informat ion l i s t e d includes dimensional requirements ( ins ide diameter, outs ide diameter, and length), thermal parameters (downhole

temperature maximum operating temperature o f equipment, and t ime requi red downhole), and other important features such as power d iss ipa t ion o f the

equipment and the s ize and number o f wires required t o pass i n t o the flask. I n appl icat ions where overa l l t o o l diameter must be kept t o a minimum, a

s i t u a t i o n can be encountered where there i s simply not enough room t o feas ib ly inc lude a PYROFLASK. I n these instances, considerat ion can be given t o the i n t e g r a l PYROFLASK/pressure housing. Note t h a t i n t h i s design the outer s h e l l i s not t h i n but a th ick, high-strength mater ia l t h a t not only funct ions as the pressure housing bu t also saves considerable space.

38

F i g . 4 . Thermal performance t e s t i ng . Figure 6 shows an actual f lask made by VBC, which has a 1.688-in. o.d.

and a 1.210-in. i.d., representing a t o t a l annular thickness o f less than 0.25

i n . whi le exh ib i t i ng a pressure r a t i n g o f 20 000 ps i . This combination Of

diameters and external pressure capab i l i t y would be v i r t u a l l y impossible i f the f l a s k and pressure housing were two separate components.

This u n i t a lso i l l u s t r a t e s the incorporat ion o f a feedthrough o r penetrat ion through the closed end o f the f lask . With t h i s feature, wires which run i n t o the f lask can pass through the closed end t o equipment beyond.

Figure 7 shows oven-test data f o r t h i s egral PY ROFLASK/pressure environment, the i n t e r n emperature i s mai n t a i ned

5 h and below 325'F f o r 24 h Note t h a t t h e i n t e r n a l

equipment was simulated by 5.1 l b s o f aluminum. To i l l u s t r a t e the e f f e c t o f

heat capacity w i t h i n the f lask, consider t h i s same t e s t bu t w i th the i n t e r n a l equipment simulated by the same s i t e bar o f s ta in less steel. The higher heat c a p a c i t y p e r u n i t volume e x h i b i t e d by t h e s t e e l r e s u l t s i n t h e i n t e r n a l

temperature being maintained below 250°F fo r 23 h, o r 8 h longer than w i th the aluminum.

39

PYROFLASK @ DESIGN SHEET FURNISHING THE FOLLOWING INFORHATION DEFINES YOUR PARTICULAR PYROFLASKwAPPLICATION. VBC ENGINEERS CAN THEN SPECIFY THE OPTlHUH FLASK OES16N TO HEET THE REPUIREHENTS.

COHPANY WANE* A0 ORES S1

~

MAHE: TEL. NO.

DlHENSlONAL REPUIREHENTS

INSIDE OIAHETER. HlNlHUR

LENGTH OF PAYLOAD OVERALL LENGTH, HAXIHUH

OUTSIDE DIAHETER. n A x i n u n

THERHAL REPU lREHENTS1

OOWNHOLE TEtlPERATUREl HAXIHUH INTERNAL FLASK TEHP.1 TlHE REPUIRED DOWN HOLE1 POWER DISSIPATION OF

FLASK CONTENTSl

WIRES REQUIRED TO PASS INTO FLASK1 PUANTITY. SIZE. t HATERIAL OF

WEIGHT t H A T I OF PRIHARY PAYLOAD COHPONENTS

OVERALL

I 1 PAVLOAO ' LEH6lW INSULAllN6 SIOPPER

HECHANICAL REPUIREHENTS1

ATTACHHENT FEATURES1

SKETCH I F REP'O.) WE16HT OF PAYLOAD1 EXPECTED SHOCK t VIBRATION LOADS

(TAPPED HOLESETC. ATTACH

DURING TRANSPORTATION OR USES

AH B I ENT PRESS UR E1

SPECIAL FEATURES1

INSULATING STOPPER INTEGRAL PRESSURE HOUSING1 SPECIAL HATERIALS*

C 0 NTAC T

CONDlTlONSl / I O X 529. IARICX LANE

no6uR*. IlASSACHUSillS 01601-0529 VACUUM. BARRIER CORPORA TION 617-933-3570 rncr 324937

Fig. 5. A standard form utilized for evaluating flask application.

PRESSURE

FEATURES \ SEAL

I t

1.69 DIA

I

EVACUATED MU LT I -LAY ER INSULATION

l/4' DIA FEED-THRU

i

e 66.00

L 73.00 _I

Fig. 6. Integral PYROFLASK/pressure housing.

>

c *

.

n e 5

W

7 a

a W Q. z W I-

500

40 0

300

200

100

0

INTERNAL EQUIPMENT SIMULATED WITH8 A - 51 CU. INCHES ALUMINUM 15.1 LBS) B - 51 CU. INCHES STEEL (14.8 LBS)

0 2 4 6 6 10 12 14 16 18 20 22 24

TIME (HOURS)

F i g . .7 . Thermal performance.

Over the years, Vacuum Bar r i e r has created PYROFLASK designs t o solve p a r t i c u l a r l y d i f f i c u l t appl icat ions. Our design v e r s a t i l i t y al lows the use o f unique, high-performance mater ia ls t o meet i nd i v idua l requirements. Also, t o a s s i s t i n development o f designs, Vacuum Bar r i e r o f f e r s thermal analysis

through use o f our computer program. We hope t h i s b r i e f overview o f PYROFLASK features and c a p a b i l i t i e s w i l l

be o f assistance when you are considering f u t u r e thermal p ro tec t i on requirements.

,

GEOTHERMAL INSTRUMENT THERMAL PROTECTION

Glor ia A. Bennett Los Alamos National Laboratory

Los Alamos, NM 87545

The development o f the geothermal energy resource depends i n p a r t on the success i n gathering accurate data t h a t w i l l a i d i n character iz ing a geothermal we1 lbo re and i t s associated rese rvo i r -- both dur ing reservo i r growth and during i t s useful l i fe t ime. Instrumentation capable o f providing geophysical data from a hot wellbore must (repeatedly and r e l i a b l y survive h o s t i l e thermal conditions. The purpose o f the ana ly t i ca l work on these systems i s t o (a) extend the thermal l i f e t i m e o f an instrument a t a stated temperature o r (b) increase the surv iva l temperature f o r a stated thermal

1 i fet ime. The Los Alamos National Laboratory thermal protect ion system design goal i s 320°C.

Thermal protect ion systems present ly used i n the indust ry can be d iv ided i n t o three categories: (a) none, (b) s ing le t r i p , and (c ) passive protect ion. The instruments w i th no thermal protect ion system are e i t h e r purely mechanical

o r have hardened sensors o r e lect ron ics t h a t requi re no protect ion. The instruments good f o r a s ing le t r i p are protected by a massive sonde t h a t

provides enough thermal l a g t ime f o r one round t r i p . The passive thermal p ro tec t i on systems are s p e c i f i c a l l y designed t o provide extended thermal protect ion a t h igh temperature.

The Los Alamos National Laboratory i s involved i n and has completed an extensive model1 i n g e f f o r t o f the passive thermal protect ion systems present ly i n use. The numerical methods used encompass both the f i n i t e element models and the f i n i t e difference models of the major system components, which are the

hot service dewar, a heat sink, and t h e i r associated heat t ransfer paths. The models are used t o generate parametric data as t o changes i n the behavior of

*

c

the thermal p ro tec t ion system caused by changes i n any o f i t s components. The

changes can be mounting hardware mater ia l changed from s tee l t o brass o r aluminum on a heat pipe, change i n a heat s ink mater ia l from aluminum t o a

f u s i b l e mater ia l , changes i n the r e l a t i v e s ize o f a heat sink, and changes i n the physical arrangement o f components i ns ide a dewar f lask. This method o f a r r i v i n g a t a design change i s cos t ly i n terms o f research and development

ef for t , which might appear as a "hunt and peck" method. But the extensive modell ing provides informat ion from which t o make an i n t e l l i g e n t choice for a design change t h a t leads t o improvements i n thermal performance. I n t h i s way,

the "hunt and peck" process i s confined t o an engineer and h i s models ra ther than invo lv ing numerous e l e c t r i c a l and mechanical technicians , designers,

draftsmen, and machinists. Results from the models provide data about the heat f l u x enter ing the

ins t rument , t h e temperature h i s t o r y f o r any p o i n t i n t h e model, and t h e temperature f i e l d a t any t ime during the simulation.

(a) a

reversal o f the thermal potent i a1 between the e lect ron ics compartment and the heat s ink t o a l low heat flow from the e lec t ron ics i n t o the heat s ink and (b)

an increase i n the conductance o f the heat t rans fer path by a fac to r o f 1OOX.

The r e s u l t i n g improvement i n thermal l i f e t i m e i s a fac to r o f 4X. Thermal mode l l i ng w i l l con t i nue t o be used a t Los Alamos N a t i o n a l

Laboratory t o s o r t through design ideas before they are committed t o hardware.

Design improvements t h a t have been rea l i zed inc lude the fo l lowing:

44

THE THEORY AND DESIGN OF DOWNHOLE THERMAL PROTECTION SYSTEMS FOR DOWN HOL E I N STRUM EN TAT I O N

by

Richard L. Hack PDA Engineering

1560 Brookhollow Drive Santa Ana, CA 92705

The cont inuing search f o r natural gas and petroleum reserves, as we l l as searches f o r geothermal energy, has forced d r i l l e r s t o cont inual ly go deeper

and t o encounter ho t te r formations than ever before. The increase i n we l l temperature leads t o a l l manner o f problems, not the l e a s t o f which i s the

i n a b i l i t y o f downhole instrumentation t o survive exposure t o these temperatures. While advances i n electronics, bat ter ies, and f i l m have

produced state-of-the a r t instrumentation capable o f sustained 300°F exposure o r more, many o f the deeper wells, geothermal wells, and steam i n j e c t i o n wel ls

have a downhole temperature o f 500°F o r more, and i t does not appear t h a t e lect ron ics w i l l catch up w i th the higher w e l l temperatures i n the near future.

Insulated housings f o r the instrumentation provide a v i a b l e means of logging o r surveying the high-temperature environments w i th low-temperature

instrumentation. A proper ly designed insulate,d housing can provide many hours of t ime downhole before the i n te rna l temperature approaches the instrument's l i m i t .

Insulated housings are governed by the fo l lowing thermodynamic p r inc ip le :

System temperature r i s e r a t e = s iystem stem heat speci+~c i n u t heat r a t e . The goal o f an insu lated instrument housing i s t o minimize the system

temperature r i s e rate. Hence, the goal i n designing an insu lated system i s t o

minimize the heat i npu t r a t e and maximize the system spec i f i c heat. That is ,

45

J

C ,

, minimize o r el iminate heat paths and maximize the i n t e r n a l heat storage (heat

s ink). F i g u r e 1 summarizes the t h r e e modes o f heat t r a n s f e r : conduct ion,

convection, and rad iat ion. Dewar f lasks, double-wall containers w i t h r e f l e c t i v e i n t e r n a l surfaces, and evacuated space between the wal l s successful ly address each o f the heat t rans fe r modes and provide a very low ove ra l l heat t ransfer coe f f i c i en t . Work i n i t i a t e d by NASA during the space program of the 60's resul ted i n the development o f "super insulat ion," a blanket of a l t e rna t i ng layers o f r e f l e c t i v e surfaces and insu la t i ng mater ia l

as shown i n F ig . 2. When used i n combinat ion, a super i n s u l a t i o n / d e w a r housing provides a very e f f e c t i v e i n s u l a t i n g ba r r i e r . E f f e c t i v e wal l heat

t rans fe r c o e f f i c i e n t s o f 3.8 x Heat sinks can be u t i l i z e d t o provide addi t ional heat storage and improve

the system s p e c i f i c heat. Figures 3 and 4 summarize the propert ies of various

Btu/h-ft-"F are possible.

mater ia ls useful as heat sinks. Phase change mater ia ls can provide a very good means o f heat storage and temperature plateaus t h a t may be useful w i t h c e r t a i n instruments.

Dewar f l a s k s r e t a i n i n t e r n a l l y generated hea t as w e l l as keep o u t

external heat. Instrument power d i ss ipa t i on w i l l dominate the system

EI.IMINAI'E CONIXJCI'ION PA111 Q ~ D . = > -0

Fig. 1. Modes o f heat t ransfer and means t o minimize heat t ransfer.

46

"SUPER-INSULATION" - NASA DEVEIDPED FOR SPACE PROGRAM

MULTIPIX LAYERS OF IIIGIILY REFLECTIVE FILM WlTll INSUIATING LAYERS BETWEEN 'ID MINIMEE CONIXJCI'ION

1NSIli.AliNG IAYLKS

I I

Fig. 2. A b lanket o f a l t e rna t i ng layers o f r e f l e c t i v e surfaces and i n s u l a t i n g mater ia l .

performance a t l eve l s higher than 5 W and, i n many cases, i s the main fac to r

i n inf luencing the system performance. Aside from the power dissipat ion, the instrument provides a major

con t r i bu t i on t o the ove ra l l system s p e c i f i c heat. Electronics and PC boards provide l i t t l e heat sink whi le the metal chassis and 'housing o f f e r more heat storage

Knowing the various modes o f heat t ransfer, i n t e r n a l d issipat ion, and the

I c o n t r i b u t i o n s t o the system s p e c i f i c heat f r om housing, heat s ink , and

i ns t rumen t , a p r e d i c t i o n o f t h e o v e r a l l system performance can be made. Adjustments t o the heat transfer paths o r the heat s ink can be made t o t a i l o r

the performance t o the speci f i c requirements . Thermoshields can b constructed w i th both e l e c t r i c a l and mechanical

feedthroughs. However, a feedthrough provides another heat t rans fe r path t o the payload compartment t h a t u l t i m a t e l y degrades the system's 'performance. Thermoshields can a lso incorporate an i n t e g r a l pressure vessel ra the r than

requi re a separate _pressure housing . Figure 6 det conf igurat ion o f

Figure 5 d e t a i l s the modes o f heat t rans fe r f o r a Thermoshield.

I

ressure vessel Thermoshield. -~ - _ .

1 I

47

F i

I IIEATSINKS ARE USED TO STORUABSORB IlEAT

I VARIOUS MATERIALS FOR IIEATS1IIELI)S I ALUMINUM .208 .0203 GOODTlIWMAL D114'USIVITY

COPPER .09 I .0294 EXCELLENT THERMAL DIFFUSIVITY, APPKOX. 2 x $5.5

STAINIBSS STEEL .11 (300 SERIES)

BERYLLIUM .45 I .031 I VFXY GOOD (VOLUME)

POOR DIFbVS%TY

.0338 I BFSTCpOFANY METAL EXTREMELY 111G11 PKICE, APPKOX. 100 X SS.S. BY WElGliT, 80 X BY VOLUME.

I PHASECIIANGE GOOD FOR TEMPERATURE PLATEAUS. MATERIALS NOT ALWAYS B E l T E K l l I A N SOLIDS

DEI'ENDENT U M N TEMPERATURE RANGE) (VARIOUS MELTING POINTMETALS)

I I

g. 3. Propert ies o f various mater ia ls useful as heat sinks.

The need f o r instrument dewar housing w i l l always ex i s t . However, the

increased desire t o stay down longer a t higher temperatures w i l l eventual ly step beyond the c a p a b i l i t i e s o f dewar systems. M ic ro re f r i ge ra t i on systems used i n conjunction w i th dewars w i l l provide v i r t u a l l y un l imi ted exposure t o

t h e h i g h temperatures now be ing encountered. However, a v i a b l e m i c r o - r e f r i ge ra t i on system has not y e t been devel oped.

Fig. 4. Graphs of sensible heat gain phase change vs s o l i d weight and volume.

48

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1 I

F i g . 5. Thermos h i el d performance analysis .

0 Integral one-piece design 0 Reduced weight and outside

0 Increased internal space 0 Durable 0 Choice of pressure housing

diameter

materials - Sitronie 50 - l i - 4 PH - lnconel i18 - Ocher material available to meet your strength and environment needs

0 Customer specified ambient ratings: 20,000 pri S O O T mica1 Electrical and mechanical feed- t h ~ ’ ~ available

SPECIFIED IWTERFACE

Fig. 6. Integral pressure vessel flask.

4 9 / 5 3

* CROSSWELL ACOUSTIC TRANSCEIVER

by

Raymond L. Jermance Los Alamos National Laboratory

Los Alamos, NM 87545

I . INTRODUCTION Crosswel l a c o u s t i c surveys a re t h e optimum method o f measur ing t h e

proper t ies o f rock between adjacent wellbores. Because o f t h i s fact , the Earth Science Instrumentation Group (ESS-6) decided t o design and f i e l d a high-temperature crosswell acoustic transceiver o r CAT system.

the t ransmit ter -- a constant, r e p e t i t i v e , cont ro l l e d acoustic source; the receiver -- t o measure the acoustic wave a r r i v a l i n the adjacent borehole; and the surface data acqu is i t i on and contro l system.

The geophysists f o r whom the system was designed supplied us w i th the fo l lowing speci f icat ions

1) Environment

The CAT system consists o f three major subsystems:

a) Geothermal f l u i d -- 250°C a t 10 000 p s i 2) Transmitter

a) Magnetostr ict ive type oules o f energy per pulse

c ) Variable f i r e r a t e (1 t o 5 shots/sec) d) Source frequency centered a t *lo kHt

e t ransmi t ter output monitor (shotbreak) ~

- a) P iezoelect r ic c rys ta l transducer (0-5500) b ) Frequency respons w i t h i n 1 dB from 1 t o 20 kHz c ) Gain contro l led u a l l y o r automat ical ly from the surface

51

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In order t o f a c i l i t a t e t he d e s i g n and f a b r i c a t i o n of t he downhole sections of the system, the modular design approach was uti l ized. Modular design allows f o r simplified wire rout ing , minimizes the number of h igh - pressure feedthroughs and electrical connectors , and greatly simp1 ifies assembly and disassemblies for easy breakdown of tools for f ield servicing, s h i p p i n g , etc.

The downhole assemblies consist of four main modules. 1) Centralizers -- The centralizers hold the tool i n the center of the

we1 1 bore. Centralizers are identical for both the transmitter and receiver. 2) Transducer Cavi t ies -- These special stand-alone u n i t s ho ld the

transducer and Teflon windows. To keep the windows a t a very low different ia l pressure, a pressure equalization p is ton balances borehole f l u i d pressure and s i l icon o i l pressure inside the cavity.

3) Electronic and Dewar Assemblies -- Electronics mounted inside a dewar flask are thermally protected by a eutectic material heat s i n k .

4) Cablehead Subassemblies -- These subassemblies are used t o interface too l s t o the 7-conductor wireline.

11. TRANSMITTER (see Fig. 1)

Electrically, the transmitter is f a i r ly simple. Up t o 200 V of alternating current are sent downhole via two wireline conductors. The ac voltage i s stepped up i n a voltage t r i p p l e r and charges the two 6-uf capacitors t o ~1600 V . A f i r e pulse generated uphole i s sent downhole on a single wireline conductor. The f i r e pulse i s delayed and shaped i n the f i r i n g c i rcu i t and fires the SCR. The SCR f i r i n g discharges the capacitors through the scroll windings, generating the acoustic wave. An accelerometer mounted on a bulkhead near t he s c r o l l s generates a shotbreak s i g n a l , which i s amplified i n the tool and transmitted uphole. Dewar temperature is also measured and sent t o the surface.

111. RECEIVER (see Fig. 2) Electronically, the receiver is more complex than the transmitter. The

crystal , located i n the transducer cavity, converts the acoustic wave from the transmitter i n t o an electrical signal. The signal is amplified by a charge amplifier and two stages of digi ta l ly programmable, variable-gain amplifiers.

52

-.

* t

F i g . 1. Acoustic transcei ver t ransmi t ter . A low-gain s ignal taken from the output o f the f i r s t var iab le gain ampl i f ier and a high-gain s ignal from the second stage are fed t o VCO's along w i th the o u t p u t o f a dewar temperature sensor. The VCO's a r e mixed, and t h e FM composite signal i s t ransmit ted t o the surface v i a w i re l i ne conductors f o r

storage and processing. A s e r i a l gain word from uphole feeds a UART c i r c u i t . The p a r a l l e l o u t p u t bus o f t he UART i s then used t o s e t t h e g a i n o f t h e d i g i t a l l y programmable amp l i f i e rs

Variable gain i s necessary i n the receiver f o r several reasons. The ceramic p iezoe lec t r i c mater ia l used i n the c r y s t a l transducer experiences an appreciable loss i n s e n s i t i v i t y a t elevated temperatures. Tests o f these c rys ta l s show the output i s -11 dB a t 150°C from room temperature. Therefore,

due t o changes i n acoustic t ransmissabi l i ty o f geologic s t r a t a i n the borehole and the f a c t t h a t transducer s e n s i t i v i t y i s i n d i r e c t l y proport ional t o the

53

Fig. 2. Acoustic transceiver receiver.

temperature gradient o f the borehole, var iab le gain becomes a very useful feature.

A

TFE Teflon window separates o i l i ns ide the cav i t y from borehole f l u i d and offers excel lent coupling. Also, t o keep the receiver s ignal f ree o f unwanted noise, a Faraday sh ie ld around the transducer c r y s t a l i s u t i l i z e d along w i t h spec ia l l y designed central izers. Foam metal i s used i n the i n te r face area

between the cen t ra l i ze rs and the t o o l body t o minimize surface noise t r a v e l i n g down the wellbore from entering' the tool .

Acoustic coupling i s enhanced by o i l f i l l i n g the transducer cav i t ies.

I V . SURFACE SYSTEM

The surface system i s t h e c o n t r o l l e r f o r bo th t h e t r a n s m i t t e r and receiver. The FM composite s ignal from the receiver i s f ed through

54

discr iminators, and the raw signals are then stored on magnetic tape. The

s ignals are a l so fed i n t o a gain contro l box where the amplitude i s measured and the gain changed i f necessary. Dewar temperatures f o r the too l s are also d i spl ayed .

A computer contro ls the f i r i n g r a t e o f the t ransmi t ter as a funct ion o f depth o r t ime and a lso s t a r t s and stops the tape recorder. Computer contro l of the f i r i n g r a t e and recorder expedites 1 oggi ng and conserves precious downhole operating time.

A crosswell survey consists o f a c o l l e c t i o n o f scans i n which a

r e p e t i t i v e s i g n a l source, o r t r a n s m i t t e r , i s moved i n one w e l l between pos i t ions a t comparable distances above and below the depth o f a receiver

s t a t i o n e d i n a n e i g h b o r i n g we1 1. S tack ing r e c e i v e r waveforms t o t h e i r corresponding depths produces a scan as i l l u s t r a t e d i n Fig. 3. Since data i s stored on magnetic tape, geophysists can process i t using a Fourier analyzer. From t h i s processing, tomographic images can be produced forms o f analysis .

as wel l as other

I-- 50ms- I 6435ft and 6430ft Scans

Fig. 3. Scan of stacking receiver waveforms t o t h e i r corresponding depths.

1

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c

*

.-

DEVELOPMENT OF A NEW BOREHOLE ACOUSTIC TELEVIEWER FOR GEOTHERMAL APPLICATIONS

by

Troy K. Moore Los Alamos National Laboratory

Los Alamos, NM 87545

ABSTRACT

Current ly Westfal ische Berggewerkschaftskasse (WBK) of West Germany and the Los Alamos National Laboratory o f the United States are j o i n t l y developing a borehole acoustic televiewer f o r use i n geothermal wellbores. The too l can be described as f i v e subsystems working together t o produce a borehole image. Each of the subsystems w i l l be described.

I. INTRODUCTION

The too l described i n t h i s paper i s an extension o f the SABIS (Scanning Acoustic Borehole Image System) developed by WBK (Hinz and Schepers, 1983). The new version not only w i l l be temperature hardened f o r geothermal appl icat ions b u t w i l l incorporate several new ideas.* General t o o l s p e c i f i c a t i o n s are found i n F ig . 1. The scope o f t h i s paper w i l l be t o describe i n general the subsystems o f the televiewer.

The acoustic p a r t transmits and receives each acoustic pulse used t o map the borehole wal l . The r e f l e c t e d signal i s processed by the downhole electronics. Result ing data are PCM encoded and transmit ted t o the surfac Once the

*Information provided t o K. H in t by B. Dennis, Los Alamos National Laboratory

The borehole televiewer can be broken i n t o f i v e subsystems.

i a a logging cable.

(1985).

57

<

data a r r i v e a t the surface, the uphole control u n i t records the data on tape

as wel l as provides the user w i t h real- t ime outputs. Since the data W i l l

reside on tape, mission spec i f i c o f f - l i n e processing procedures are e a s i l y app 1 i ed .

I n addi t ion t o mentioned design speci f icat ions, two other c r i t e r i a have been addressed. The acoustic p a r t o f the t o o l has been placed as f a r forward on the too l as possible i n order t o provide a 'look-down" perspective (Fig. 1). Also, subassemblies have been modularly designed t o a i d i n f i e l d assembly.

11. ACOUSTIC SUBASSEMBLY The acoustic system houses two p iezoe lec t r i c c rys ta l s mounted 180" apart

on a r o t a t i n g b l o c k . E i t h e r t h e 1.3-MHz o r t h e 625-kHz c r y s t a l s may be selected v i a the uphole control un i t . The c rys ta l s are rotated i n a s i l i c o n

o i l - f i l l e d c a v i t y a t 360 rpm by an ac synchronous motor. A Teflon window maintains separation between the s i l i c o n o i l and borehole

f l u i d s . Pressure balance i s preserved using a f l o a t i n g p i s ton arrangement. Communication w i t h the motor and t ransducer t r a v e l s th rough a s l i p r i n g assembly and a high-pressure connector before reaching the downhole e lect ron ics . 111. DOWNHOLE ELECTRONICS

The downhole e lect ron ics subsystem s based around an I n t e l 8085 microprocessor responsible f o r cont ro l o f the downhole data c o l l e c t i o n and transmission. Heat developed in te rna l 1 y by the downhole e lect ron ics and heat from the environment are stored i n a heat sink. The e lect ron ics and heat s ink are packaged i n a dewar f o r thermal protect ion.

For each shot, t h e t r a v e l t i m e of t h e f i r s t a r r i v a l and t h e peak amplitude o f the re f l ec ted signal are measured. To i n i t i a t e a shot, the microprocessor t r i g g e r s the selected c r y s t a l w i t h a pu l se . A f t e r r i ngdown , the c rys ta l i s reconfigured t o act as a receiver o f the ref lected signal. A t

a predetermined time, the e lect ron ics begin l i s t e n i n g for the return. The received signal i s processed by an amp l i f i e r w i th an adjustable gain. The peak amplitude detected i s retained. Both the time t o begin the l i s t e n i n g window and the amp l i f i e r gain are determined, based on previous shots, by the CPU.

58

b .

3 CONDUCTOR FEEDTHRU

THERMAL FLASK

ELECTRONICS

GENERAL SUMMARY O D 2 7 5 ” 70 mm

1 WlO CENTRALIZERS 1 16 PIN HIGH PRESSURE

0. 0. 3.375 *‘ 86 mm BULKHEAD FEEDTHRU f WlCENTRALlZERS I

CENTRALIZERS 15 ’ 381 mm

LENGTH 14 ft 4.3 M

PRESSURE gMK) psi

TEMPERATURE 275 ’ c 4 4 HOUR RUN AT 260‘ C

A C MOTOR LOGGING RATE t FAST SCAN 1 10 ftlrnin 3 mlmin

TRANSDUCER ROTATION 360 rpm

CRYSTAL FIRE FREa 3072 Hz MARK SWITCH

1 OR 512lREVOLUTlON 1

MAX HOLE DIAMETER #)in W c m

10 CHANNEL SLIP RINGS 1 USING C water = 60.OOO inlrec I

FLUX GATE MAGNETOMETER

ROTATING TRANSDUCERS

WINDOW

PRESSURE BALANCE PISTON. CYLINDER

Fig. 1. Borehole acoustic televiewer.

Travel t ime o f the f i r s t a r r i v a l i s the t ime between f i r i n g the c r y s t a l and the ref lected signal amplitude exceeding a threshold. The threshold i s

selected based on previous shots. To reduce noise i n the received signal, the microprocessor synchronizes the s ignals d r i v i n g the ac motor w i th receiver

’59

ac t iv i t ies . T h i s will guarantee tha t l istening for a return and switching the motor current are mutually exclusive events.

Borehole temperature, temperature inside the dewar, and output from the three i ncl i nometers represent data requi red on1 y once per revol u t i on. A t specific times dur ing a revolution, these conditions are sampled and available fo r encoding. A mark is generated t o indicate a complete revolution of the acoustic part . O u t p u t from the fluxgate coil i s interpreted t o determine which shot most nearly aligns w i t h magnetic north.

For uphole transmission, the peak amplitude and travel time values are appended together. Two additional b i t s are added t o allow ser ia l encoding o f once per revolution parameters. The resulting data word i s then PCM encoded.

IV. LOGGING CABLE The PCM-encoded data are transmitted t o the uphole control u n i t via 6600

m of 7-conductor or coaxial logging cable. Power for the downhole electronics is s u p p l i e d using the logging cable.

V. UPHOLE CONTROL UNIT The uphole control u n i t (F ig . 2) i s constructed around the Siemens PMS-T

85D Microprocessor System (Intel 8085 CPU) . T h i s subsystem provides the user interface, controls the real-time outputs, and records the collected data on tape.

The uphoTe control u n i t provides the interface between the tool and the user. To i n i t i a t e and control tool operation, commands are entered a t the system terminal. The format of the real-time ou tpu t s can be changed a t any time. Once-per-revolution parameters displayed on the system terminal provide i n s i g h t i n t o the condition and operation of the tool .

Upon arrival a t the surface, the data stream is decoded, and the ser ia l data are s t r ipped off and placed i n a parameter buffer. Travel time and peak amplitude values are separated and written t o buffers. Date/time and logging ra te values are i n p u t from external sources and included i n the parameter buffer.

Data collected by the tool are displayed on a color monitor. A hardcopy may be generated by the gray scale recorder. Data are mapped t o in tens i t ies via a user- selected look-up table. Using mark and magnetic north information,

60

Siommnr Microprocoaaor

th. Logging R ~ t o Information

Fig. 2. Uphole control system.

data from a revolution are rotated t o position the shot representing north as the first pixel i n a ras ter scan l ine. Values from successive revolutions are inserted i n t o the graphics c o n t r o l l e r such t h a t the o u t p u t of the co lor monitor will i l l u s t r a t e moving along the borehole.

Data are written t o a 1/4-in. streaming tape on a revolution (mark-toinark) basis. When a l l data from a revolution are present, the three buffers are written t o tape as three records. A second s e t of buffers are present t o a1 low concurrent 1/0 operations.

V I . OFF-LINE PROCESSING Real -time outputs may not provide suff ic ient information for an

application. Off-line processing allows the user t o manipulate collected data t o meet specific needs.

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1

The 1/4-in. tape provides a medium f o r t rans fe r r i ng data t o a minicomputer for f u r the r analysis. A f i r s t step may be t o organize the data i n t o a standard format before any addi t ional processing. Operations involved

may include (1) data ca l ibrat ion, (2) r o t a t i n g data using nor th information, (3) evaluation of borehole deviation, and (4) correct ion f o r t oo l not centered i n borehole. Once i n i t i a l processing has occurred, the data c o l l e c t i o n may be broken up i n t o segments and placed i n d i r e c t o r i e s representing ranges o f depths

Such algori thms

may include image enhancement, s t a t i s t i c a l analysis, pa t te rn recognit ion, etc.

VII. SUMMARY A borehole acoustic televiewer i s being developed j o i n t l y by West Germany

and the United States. As the t o o l moves along the borehole, u l t r a s o n i c pulses are f i r e d from a r o t a t i n g head. The amplitude and t rave l t ime o f the r e f l e c t e d pulse are measured by the downhole e lect ron ics and transmit ted t o the surface v i a the logging cable. The uphole control u n i t records the data

and provides real- t ime output t o the user.

REFERENCES

A t t h i s point, mission spec i f i c software may be applied.

1. K. H in t and R. Schepers, "SABIS (Scanning Acoustic Borehole Image System -- The D i g i t a l Version o f the Borehole Televiewer," Eighth SPWLA London Chapter Europe Formation Eva1 uat ion Symposium Transactions (1983)

62

SPUTTERED THIN-FILM STRAIN-GAGE PRESSURE TRANSDUCER FOR H I G H -TEM P ERkTURE A PPL I CAT IONS

by

Robert Backus CEC Instrument D iv is ion

325 Halstead St ree t P.O. B in 7087

Pasadena, CA 91109-7087 ,

presented by

Joseph A. Catanach Los Alamos National Laboratory

Los Alamos, NM 87545

CEC's sputtered, th in - f i lm, strain-gage pressure spec i f i ca l l y designed f o r severe environment appl icat ions.

transducers are

They are widely . .

used on rocket launch vehic les where they are subjected t o high l e v e l s of

shock and v ibrat ion. They to le ra te h igh ly corrosive pressur iz ing f l u i d s and operate a t temperatures ranging from t h a t o f l i q u i d hydrogen (-423°F) t o high- pressure steam above 500OF. The successful performance o f these transducers i n such severe environments r e s u l t s from a v a r i e t y o f design factors,

s t r i ngen t cont ro l o f fabr icat ion processes, and special aging operations t o s t a b i l i z e the e n t i r e sensing structure.

The processing steps tha t are essent ia l t o production o f these stable, w i de-temperature- range sensors are out1 i ned herein .

The sensor beams o r diaphragms are c a r e f u l l y machined t o t i g h t tolerances , annealed, age-hardened, and stress -re1 ieved. The surfaces t o be gaged are lapped f l a t and polished t o a m i r ro r f i n i s h f ree o f surface s t r a i n and mechanical defects. A number o f these beam. o r diaphragm substrates are then placed i n a sput ter ing chamber f o r deposi t ion o f the t h i n - f i l m sensor components.

63

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I n the sputter ing chamber, low-pressure argon gas i s ionized by an rf

f i e ld . The ionized gas molecules are accelerated toward a f l a t p l a t t a r g e t made o f the mater ia l t o be deposited where they impact, dislodge, and i o n i z e

atoms o f the ta rge t mater ia l . The dislodged atoms are, i n turn, accelerated toward the substrates a r r i v i n g w i t h s u f f i c i e n t energy t o produce strong i n t e r - molecular bonds between themselves and the substrate atoms. Before

deposition, however, the process i s momentarily reversed t o sputter-etch the surface o f the substrates. This removes any remaining surface contaminants t h a t might i n t e r f e r e w i th the adhesion o f the deposited layer.

A t h i n l aye r o f s i l i c o n dioxide ($ io2) i s deposited f i r s t t o provide e l e c t r i c a l i n s u l a t i o n between substrate and s t r a i n gages. The gage mater ia l , a cermet, i s next deposited over the e n t i r e surface o f the substrates. The sensor elements are then removed from the chamber and are f i t t e d w i t h t h i n meta l masks which have openings o n l y where e l e c t r i c a l c o n t a c t pads a re required f o r connection t o the gage elements. These are again placed i n a sput ter ing chamber where nichrome i s sputtered onto the gage material, through the mask openings. The sensor elements are again removed from the chamber, coated w i th a layer o f photoresist mater ia l and exposed t o u l t r a v i o l e t l i g h t

t h rough a pho tog raph ic mask t o d e f i n e t h e gage elements. A l l unexposed photores is t i s then removed, leaving only t h a t which defines gage geometry and a p o r t i o n o f the m e t a l l i c contact pads. The assemblies are again placed i n the sputter ing chamber f o r sputter-etch removal o f a l l gage mater ia l except t h a t protected by the photoresist. On removal from the chamber, the gages are probed t o v e r i f y r e s i s t a n c e , matching, and d i e l e c t r i c i s o l a t i o n . A f t e r

thermocompression b a l l bonding of O.OO2-in.-diam gold leads t o the contact

pads, the completed sensors are annealed and thermally aged wel l above maximum operating temperatures and then we1 ded i n t o transducer assembl i e s .

After assembly, the completed transducers go through an extensive pressure and temperature-aging process before compensation and f i n a l

c a l i b r a t i o n t o ensure t h e i r long-term operational s t a b i l i t y . The high-temperature CEC 1000-0009 assembly contains only m e t a l l i c and

ceramic materials, consequently i t w i l l operate continuously a t temperatures up t o 600'F.

64

USE OF HIGH-TEMPERATURE TRANSDUCERS I N GEOTHERMAL WELL LOGGING

Jerry Kolar Los Alamos National Laboratory

Los Alamos, NM 87545

ABSTRACT

Dur ing the month o f September 1985, Group ESS-6 o f the Los Alamos National Laboratory was involved i n logging several geothermal -we l l s i n the Miraval les Geothermal F i e l d o f Costa Rica. This o p e r a t i o n was i n a s s o c i a t i o n w i t h t h e U.S. a i d program t o Central America. This repo r t describes some o f the high-temperature transducers and components used i n t h i s operation and defines some o f the dat taken w i th the use of these transducers.

I . I NTROOUCTION

The purpose o f t h i s repo r t i s t o s t r a t e the use of various transducers and components i n a geothermal ronment. I n a l l cases, the transducers and components were purchased the Los Alamos National Laboratory f o r use i n t h e i r downhole geothermal logging instruments.

F i e l d i n Costa The place chosen t o demonstrate t h i s usage i s the Miraval les Geothermal

I I . OPERATIONS

The logging operations i n Costa Rica were performed w i th the fo l lowing

1) casing c o l l a r l o c a t o r (CCL),

Los A1 amos 1 oggi ng t o o l s :

I

c

2 ) water-sampler, 3) 3-arm cal iper , 4) s p i nner-temperature-pressure (STP) tool w i t h CCL, and 5) temperature-pressure (TP) tool

The logging tools used i n Costa Rica contained the following major components and transducers:

1) thermistors, 2) dc motors, 3) potentiometers, 4 ) potentiometric pressure transducers, 5 ) s t r a i n-gage pressure transducers, 6) casing col lar locators, and 7 ) reed switches.

The logging operations were performed w i t h a logging u n i t tha t was outf i t ted w i t h a Hewlett Packard data acquisition system, a 7-conductor, TFE-insulated 1 oggi ng cabl e, and a Los A1 amos-desi gned cabl ehead.

111. LOGS

A. Temperature On the average the production zone temperature a t the Miravalles

Geothermal Fie1 d was approximately 24OOC. Figure 1 i s representative temperature data of Well PCM-3 under nonflowing conditions. The plot is depth i n f ee t versus temperature i n degree centigrade. The water level w i t h an isothermal layer of steam above the water level can be seen a t 850 ft. B. Water Sampler

One of the most important logging tools used i n the Miravalles logging operation was the Los Alamos water sampler. The major components i n this tool consist of a thermistor t o measure the temperature of the sample and a dc motor for opening and closing. the sample bottle.

Dur ing the f i r s t logging operat ion i n Costa Rica, the water sampler acquired six samples i n different we1 1 s under s h u t - i n and dynamic conditions . The sample b o t t l e used has a capacity of 817 mk. On the average, 550 ma of f l u i d was obtained w i t h the remainder being gases.

66

TEMP. SURVEY: Hicavollar wal 1 PGN-3 85/89/12

U

m Q R Y

coo E I50 L

+

+

+

+

+

+

+ +

+ f - / ' 4

/ + +

c 4

+

+

OEPTH (F t I

Fig. 1. Temperature data of We1 1 PCM-3.

C. 3-Arm Caliper The Los Alamos 3-arm caliper tool was used i n Costa Rica primarily for

the investigation of ca lc i te bui ldup. The major components i n this tool consist of rotary potentiometers and a dc motor t o extend the arms when ready

Figures 2, 3, 4, and 5 are representative o f the caliper data taken i n the Miravalles wells. The figures are data p lo ts of the average radius i n inches from tool centerline versus depth i n feet.

Figure 2 is a p lo t of a 100-ft section of a 7-5/8-in. s lot ted l i ne r i n Well PGM-10. The nominal inside diameter of the 7-5/8-in. liner is 6.966 i n . or 3.48 i n . from t o o l centerline. From this p l o t you can see t h a t .this section of liner is nearly 0.4 i n . under nominal inside diameter w i t h l i t t l e evidence of s lo t s . The results suggest ca lc i te bu i ldup .

Figure 3 is a plot of a 100-ft section i n the well above the plot i n Fig. 2. Here we can see the gradual increase i n inside diameter t o near-rated values, and we can now see open slots i n the liner.

t o log.

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I . . . I . . ' ' ~ " I ' ' '

3700 3720 3740 3760 3780 3800 DEPTH ( F T )

2 . 5

Fig. 2. Cal iper data from Well PGM-10.

Figure 4 i s a p l o t o f a ca l i pe r survey o f a 300-f t section of Well PGM-3. S ta r t i ng from the l e f t s ide o f the p l o t , we have a 9-5/8-in. casing w i t h a

l i n e r hanger and 7-5/8-in. l i n e r top a t approximately 1925 ft. Moving t o the r i g h t , we have a b l i n d l i n e r t o 2100 f t and a s l o t t e d l i n e r from there down. I n the middle o f t h i s p l o t above 2100 ft, we see two j o i n t s o f 7-5/8-in. b l i n d l i n e r t h a t should be smooth b u t show evidence o f being p i t t ed .

To show you t h a t we do have ind i v idua l 3-arm c a p a b i l i t y w i t h readouts, Fig. 5 i s a p l o t o f the 3 arms from the sect ion o f the we l l i n the previous

p l o t , Fig. 4. D. STP Tool

A l o g g i n g t o o l t h a t was used a g r e a t deal i n t h e M i r a v a l l e s l o g g i n g operations was the spinner-temperature-pressure tool , o r STP too l , w i t h casing co l 1 a r locator. The too l consists o f the f o l 1 owing transducers and components :

1) thermistor,

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DEPTH { F T )

Fig. 3. Caliper data from Well PGM-10.

2) potentiometric pressure transducer, 3) casing col lar locator, and 4) reed switches. The instrument is s t r i c t l y analog w i t h no dewar or active electronics

downhole. A l l four functions a re recorded continuously without any switching using a 7-conductor logging cable.

Figure 6 is a p l o t of an STP survey i n Well PGM-10 under s h u t - i n conditions. Depth is 0 t o 1200 m. The top trace i s pressure i n bars, the middle trace is spinner output i n hertz, and the bottom trace is temperature i n degree centigrade. The p lo t shows a wellhead s h u t - i n pressure of about 5 bars w i t h a f l u i d level of about 300 m. The only flow out of the well during t h i s log was some gas f l o w t h rough our control head. We can see this outgassing on the spinner output a t the water level and below for about 150 m.

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I900 1950 2000 2050 2 100 2 150 2200 DEPTH (FT)

2 ~ ' " " ~ ~ " ' " ~ " ~ ~ " ~ ~ ~ ~ ~ ~ ' ~ ~ '

Fig. 4. Cal iper data from Well PGM-3.

Figure 7 i s a p l o t o f the same wel l from 0 t o 1200 m under dynamic o r f lowing conditions. Figure 6 has a spinner scale o f 0 t o 50 Hz. This p l o t i s scaled from 0 t o 800 Hz. Here we can see the spinner response i n two-phase f low i n the upper por t ion o f the wel l , a ve loc i t y change a t a l i n e r top a t 730 m, and the b o i l i n g po in t a t approximately 850 m defined by a l l three functions.

This data was recorded whi le logging down a t a constant 50 f t /m in rate. An addi t ional note on the spinner output shows an increasing ve loc i t y

This can be a t t r i b u t e d t o a s tead i l y decreasing

The major p r o d u c t i o n zone i n t h i s w e l l i s below our l o g g i n g depth. the diameter o f our logging instrument would n o t

from the b o i l i n g po in t down. pipe diameter due t o c a l c i t e buildup.

Because o f c a l c i t e buildup, pass through the zone o f in te res t .

70

Fig. 5 . Caliper data from Well PGM-3.

I E. TP Tool TO record a l l functions of the STP tool on a 7-conductor logging cable, a

potentiometric 1 pressure transducer was used. An a l ternate pressure measurement was also used i n Costa RSca w i t h a temperature-pressure tool, o r TP t o o l The components i n this too l include a thermis tor and a s t r a i n gage-type pressure transducer rather than potentiometric. c Figure 8 i s a p lo t of a temperature/pressure survey i n Me11 PGM-10 from 0

t o 1200 m under dynamic or flowing conditions. The top trace is pressure i n bars, and the bottom trace is temperature i n degree centigrade. Again, we can define a boi l ing poin t a t 850 m by the break i n both the pressure and temperature curves. .

I I

71

STi" Survey: (5hut-ip) ritraval :cs wel? PC;H-:O

10oo

0 400 e00 1200

-0 400 BOC DEPTH CHetero)

! 900

Fig. 6. P l o t o f an STP survey i n Well PGM-10.

I V . SUMMARY

I n summary, the recent logging operations i n Costa Rica have demonstrated

the use o f several high-temperature components and transducers f o r use i n geothermal we1 1 logging .

Transducers, components, seals i nsu la t i ng mater ia l s, etc ., used i n the high-temperature logging operations i n Costa Rica were purchased from the fol lowing manufacturers: Rochester Corporation; Kemlon Products; Gulton Industr ies; E.I. DuPont Company; American Electronics, Inc. ; Dow Corning; Parker Seal ; Bal-Seal; A l len Bradley; Mu1 t i c o r e Solder; Boyd I n d u s t r i a l Rubber: Gearhart; Sparton Southwest; CEC Instruments; L i t t o n Potentiometer; Conax Corporation; Standard Wire and Cable; Hot Hole Instruments; and Hamlin.

72

b F

f . . . . . . , . . . . . . . , . . . . . . . .I'

,/' /

/" -

1 . . . . . . . I . . . . . . .

400 800 120c

. . . . . . . . . . . . F- . . . . . . . . ,

I 2501 . . . . . . . , . . . . . . . , . . . . . .

lSO0 5 400 eo0 1200

Fig. 7. Plot o f an STP survey i n Well PGM-10. T

I . . . . . . . I . . . . . . . 400 800 1200

Fig. 8. Plot o f a temperature/pressure survey i n Well PGM-10. 73/74 i ~

,

HIGH-TEMPERATURE VELOCITY TRANSDUCERS

S. E. Haggard Mark Products U.S., Inc.

10507 Kinghurst Dr ive Houston, TX 77099

ABSTRACT

The high-temperature transducers discussed i n t h i s paper are a modi f icat ion o f the moving-coil, ve loc i ty-sensi t i ve , motion transducer widely used i n seismic explorat ion i n the o i l business. They are commonly cal l e d geophones o r seismometers. I n t h i s service they are expected t o operate sa t i s - f a c t o r i l y a t any ambient temperature found from the nor th slope o f Alaska t o the Sahara desert. These condit ions range from -40°F t o 130°F.

Increasing usage o f these transducers as a component i n bottom-hole we1 1 -logging instruments a t greater depths has ra ised the service temperature requirements f o r these components

Two areas o f i n t e r e s t are af fected when the transducers are subjected t o temperatures much above 200°F. These are

1) mechanical i n t e g r i t y due t o changes i n physical propert ies o f mater ia ls i n t h e i r construction, and

2) changes i n e l e c t r i c a l character is t ics .

The mater ia ls used i n the normal transducer and t h e i r subst i tu tes f o r high-temperature appl icat ions w i l l be discussed. Changes i n e l e c t r i c a l cha rac te r i s t i cs can be predicted f a i r l y accurately by computer. Some v e r i f i c a t i o n has been made by t e s t b u t no t much over 200°F. We considered temperatures t o 500"F, which i s about the upper l i m i t f o r mater ia ls present ly being used i n t h i s appl icat ion.

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I . INTRODUCTION The transducer discussed i n this paper i s basically a very simple device

cons i s t ing of a moving c o i l i n a magnetic f i e l d . I t s s e n s i t i v i t y i s proportional t o the velocity of the coil w i t h respect t o i ts case and the product of the length of wire i n the magnetic f ield and the f l u x density of the magnetic f ie ld . The l e n g t h of coil winding i s constant as i s the f l u x densi t y a t a given temperature. Thus, i t i s a veloci ty-sensi tive transducer.

I t s co i l form has two w i n d i n g s , each on aluminum bobbins o r forms separated by an i n s u l a t i n g p l a s t i c cen te r s ec t ion . T h i s c o i l form i s supported w i t h i n two magnetic fields of opposite polarity by a pair of three- arm springs, one a t each end of the c o i l form. The c o i l s a r e wound i n opposite directions and connected i n series. Their outputs are t h u s additive.

The opposite polarity of the two magnetic f ie lds has a canceling e f fec t on any ex terna l magnetic f i e l d . T h i s type of cons t ruc t ion i s c a l l e d " H u m Bucking." Transducer output tha t i s due t o power transmission l ines or other strong f ie lds is eliminated.

The materials normally used i n the transducers's construction are such tha t their mechanical in tegr i ty i s not compromised nor are the i r e lec t r ica l character is t ics much a1 tered over the temperature range from -40°F through 200°F. However, if service temperatures much higher are t o be expected for any period of time, changes must be made.

In th i s d iscuss ion , h i g h temperature i s considered t o be continuous service a t 500°F and short-time exposure of a few hours i n the range of 525 t o 550°F b u t never t o exceed 550°F.

We examined the changes i n the ma te r i a l s used i n each p a r t of the assembly tha t are needed t o meet these service temperature requirements. A. Outer Case

over 550°F. B. Case Top and Bottom

machined from free machining yellow brass for high-temperature service. C. Tubular Hermetic Seals

Hot tin-dipped Kovar/glass seals are normally used. Unsatisfactory. A1 1 t i n i s chemically removed and both flange and tubular portion of seal are gold

Cadmium-plated steel is normally used. T h i s i s satisfactory for well

A zinc die casting of Zamak 2 i s normally used. Unsatisfactory. Part is

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electroplated. T h i s i s done t o eliminate leaching of t i n in to high-temperature solder dur ing termination. Contamination of high-temperature solder by the t i n will lower i t s melting point t o an intolerable level. Ersin HMP solder w i t h a l i qu idus of 565"Fto 574°F i s used both when soldering. the hermetic seals and terminating the coil winding internally. D. Coil Form Assembly

T h i s p a r t i s normally a molded assembly cons is t ing of two 2011-T3 aluminum alloy bobbins Joined by an insulating p l a s t i c band of 33% glass-fi l led nylon. T h i s is unsatisfactory over 200°F. For high-temperature service, the two bobbins are joined w i t h a central band machined from DuPont Vespel SP-1. I t s s e rv i ce temperature i s over 650°F when i n an i n e r t atmosphere. A l l our transducers a re evacuated and f i l led w i t h an atmosphere of dry nitrogen and hermetically sealed. The aluminum bobbins are attached t o the Vespel center section using gold-plated brass 00-90 machine screws. E. Coil Windings

Normally soldereze-insulated copper magnet wire is used. T h i s insulation is obviously not satisfactory for this service. Here we use Teflon-insulated ~

wire good for 500°F continuous and much higher for short periods of time. Ersin HMP solder i s used for termination t o the gold-plated screws. The bobbins are insulated from each other by the Vespel section, and the bobbins themselves are used for coil termination. O u t p u t i s brought out through the support springs on each end of the coil. The windings are insulated from the bobbins by a layer of 0.003-in.-thick Teflon tape. F. Support Spr ings

These springs for a l l service temperatures are the same. They are made o f BeCu Alloy 25 rolled t o l j 2 hard temper. They are chemically etched t o correct outl ine using techniques similar t o those used i n p r i n t e d ' c i r c u i t board manufacture, Dimensions are held t o closer than 0.0005 i n . After the springs a r e etched t o s ize , they a r e p r e c i p i t a t i o n hardened t o maximum properties by heat t reat ing i n a special fixture for 2 h a t 600°F. T h i s fixture performs the sp r ing t o a raised or of fse t condition when i t is not supporting the coil mass t o an amount equal t o the sag when the coil mass is applied. Thus , the springs are f l a t when the u n i t is assembled. T h i s f l a t s p r i n g condition produces a transducer w i t h an output of a h i g h degree of l inear i ty and a distortion of less than 0.2% a t high-output levels.

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Temperatures much above 500°F w i l l p a r t i a l l y anneal the spr ing mater ia l , and

t h e sp r ings w i l l sag u n t i l t he c o i l r e s t s on t h e case bot tom and t h e transducer i s inoperative. We have y e t t o encounter t h i s f a i l u r e i n service and cannot p red ic t l i f e span a t any p a r t i c u l a r temperature.

G. Magnets The magnets used are made o f Cast Alnico 8 and ground t o size.

Temperatures w i t h i n the desired range have no i r r e v e r s i b l e e f f e c t s on t h e i r magnetic propert ies. However, t h e i r magnetic strength o r f l u x densi ty does f a l l o f f by about 3.5% a t 550°F. T h i s i s a smal l amount and i s f a i r l y predictable. H. Pole Pieces

w i t h i n the desired temperature range. I . Other In te rna l Parts

There are three other i nsu la t i ng mechanical par ts made o f Vespel SP-1. As noted ea r l i e r , these are sat is factory t o over 650°F i n the atmosphere present. Two O.OlO-in.-thick i nsu la t i ng washers of 6-7 are a lso used t o

prevent ends o f c o i l assembly from contact ing the metal case top and bottom. This mater ia l has been sat is factory .

J. 0-Rings The O-rings used f o r hermetic seal ing o f the case top and bottom are of

Parker E962-85 special ethylene propylene rubber compound f o r steam service over 500°F.

I(. Changes i n E l e c t r i c a l Character is t ics The e l e c t r i c a l charac ter is t i cs o f the transducer are a l te red t o various

degrees by increase i n operating temperature. These changes are predic tab le and e a s i l y calculated w i th a simple computer program. Most o f these are most e a s i l y shown by response curves fo r the desired temperature. A ser ies Of

these curves f o r a t yp i ca l high-temperature transducer i s included w i th t h i s paper.

The natural frequency o f the transducer does not change w i th temperature as long as i t remains operable.

The open c i r c u i t s e n s i t i v i t y drops about 3.5% a t 550°F. I n most appl icat ions t h i s can probably be neglected.

The change i n resistance o f the shunt r e s i s t o r i s only 0.5%/100" and can a lso be neglected i n most cases.

These are made o f gold-plated screw machine s tee l and are not affected

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The resistance of the aluminum por t i on o f the c o i l form assembly

increases markedly wi th temperature. The open c i r c u i t damping o f the u n i t var ies inverse ly w i th t h i s resistance. Hence, open c i r c u i t damping drops

considerably with temperature i n the order o f 7%/100'. The t o t a l damping o f the u n i t i s the sum o f the open c i r c u i t damping p lus

the damping caused by the shunt res i s to r . This w i l l be m a t e r i a l l y a f fec ted by temperature.

The resistance o f the copper winding increases markedly w i th temperature y e t i s e a s i l y calculable.

The damped output o f the u n i t i s equal t o the undamped output times the value o f the shunt r e s i s t o r div ided by the sum o f the c o i l resistance p lus the

value o f the shunt res i s to r . I n t h a t the c o i l resistance. increases markedly w i t h temperature, the damped output w i l l f a l l o f f g rea t l y w i t h temperature a t higher values of t o t a l damping. Since most transducers are shunted t o g ive a t o t a l damping of 60 t o 70% o f c r i t i c a l , the damped output o f the u n i t w i l l be g r e a t l y reduced a t higher temperatures. This i s qu i te evident on the fami ly o f curves presented w i t h t h i s paper. These curves take i n t o consideration a l l var ia t ions , however small .

It w i l l be noted on the 8-Hz curves f o r 350°F and higher t h a t no 70% i s shown. It i s n o t p o s s i b l e t o dampen t h i s phone t o t h a t degree a t t hose temperatures w i th a r e s i s t i v e shunt.

I hope I have given you an overview of the construct ion problems involved i n the modi f icat ion o f se i smi c ve l oc i ty-sensi ti ve transducers f o r downhol e app l i ca t i on and the evaluation o f t h e i r temperatures . e l e c t r i c a l character is t ics a t elevated

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PHONE AT w c

PHONE AT 900 DEG c

D OJoeOHYs 0.700

PHONE AT 400 DE c

80

E . PHONE AT 250 DEG c

PHONE AT 350 DEC c

"

PHONE AT 68 DE0 C

R E S P O N S E C U R V E G15LB-TW-HT GEOPHONE

0 l/h!,i I I1111 I c 1987oBys 0.m

FREQUENCY - - H E R T Z I d u n + o o c f ! 8 g s 3 g p g 8

D O S 3 O B y s 0.m .1

PHONE AT 300 DEG C

e 6 4 L-15U-TW-HT GEOPHONE

PHONE AT e50 DEC c

PHONE AT s o eo c

B 11112OByS 0.m c 62ooBys 0.600 - N n + o c m ~ 8 o o o o o o o n ~ n c c ~ p

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A HIGH-TEMPERATURE TRANSDUCER FOR MEASURING LOW-LEVEL DIFFERENTIAL PRESSURES I N A HIGH-STATIC PRESSURE FIELD

Daniel McMahon Endevco

30700 Rancho Viejo Road San Juan Capistrano, CA 92675

ABSTRACT

A new pressure transducer has been designed u t i 1 i z i n g state-of-the-art s i 1 icon micromachi ning processes. Th is t ransducer has been p r i m a r i l y designed f o r use as a low-level pressure sensor

-and, i n some instances, a h igh- in tens i ty m i crophone Manufactured so le l y from s ing le c r y s t a l s i 1 icon, the sensing element provides excel lent l i n e a r i t y and low hysteresis. This paper contains a descr ip t ion o f t h i s sensor and j t s use i n a downhol e appl icat ion f o r f l u i d density measurement.

I. INTRODUCTION A c lass i ca l pressure measurement problem has been t o accurately sense

d i f f e r e n t i a l pressure i n the presence o f h igh common-mode pressure. The most frequent appl icat ion i s d i f f e r e n t i a l pressure measurement across an o r i f i c e p l a t e t o determine f l ow r a t e (V2=Ap). Another appl icat ion i s the measurement

This i s determined by measuring the pressure d i f ference between two points i n a known column o f l i q u i d (y=P/h). An example o f such an appl icat ion i s f l u i d densi ty measurement i n a deep we l l a t s t a t i c pressures of over 700 bar. Assuming the well contains a l i q u i d mixture w i th a density close t o t h a t o f water, the need i s t o measure d i f f e r e n t i a l pressure below 0.1

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bar i n a 700-bar s t a t i c f i e ld , assuming the column height i s approximately 0.5

t o 1 m.

One o f the d i f f i c u l t i e s i n making these measurements i s caused by the common-mode pressure s e n s i t i v i t y o f most transducers. This means t h a t the output of the transducer, w i th no d i f f e r e n t i a l pressure across it, changes as the common pressure t o both pressure por ts increases. When the r a t i o of the common-mode pressure t o d i f f e r e n t i a l pressure i s as high as i n the above example, measurements are usual ly not feasible. The zero s h i f t e r ro rs are excessive.

11. SUMMARY

As shown i n Figs. 1 and 2, the si l icon-sensing element i s three dimensional. The cross sect ion i n Fig. 2 shows a photomicrograph o f the pressure diaphragm. One can e a s i l y see t h a t a d i s t r i b u t e d load o r pressure on one side r e s u l t s i n stress concentrations a t Points A, B, and C where a l l the bending occurs. Stress-sensit ive mater ia ls are d i f f used i n these areas, providing the highest possible s e n s i t i v i t y t o pressure.

One version o f t h i s transducer i s being used f o r measurement i n hydrostat ic pressure approaching 1000 bar. This i s achieved by exposing the e n t i r e transducer t o the pressure and connecting the front-end pressure p o r t

t o a l i n e which i s ,less than 1 m above the transducer. A known l i q u i d i s contained i n the column between the

AWINNED A R E A two pressure i n l e t s .

\CAGES DIFFUSED INTO OPPDSIlE F A C E

Fig. 1. Diffused, etch-contoured Fig. 2. Photomicrograph o f diaphragm pressure sensor. sect ion through notches and

is lands . 84

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In f a c t , th is l i q u i d , which i s a d i e l e c t r i c f l u i d , a l s o completely surrounds the miniature transducer and provides a media barrier t o the host i le f l u i d s i n the well.

W i t h the 8510B-style transducer used i n this manner, the zero o u t p u t change w i t h 700-bar hydrostatic pressure surrounding i t i s less than 0.00 bar. T h i s resul ts i n a small measurement error. The performance of this transducer has proved t o be exemplary i n this type of application.

In this type of application i t would also be extremely d i f f i cu l t t o use one of the rather large differential pressure transmitters as used i n the process indus t ry for flow measurements. In addition, the shock and vibration would l ikely destroy a larger and more f lexible transducer.

W i t h such a high common-mode pressure and such a low d i f f e r e n t i a l pressure, one risk i s that the pressure t o both ports does not track and the difference exceeds the range of the transducer. The over-range specification of 40 p s i for the 85108 2-psi full-scale transducer greatly ass i s t s i n making this a practical measurement.

The performance characterist ics of this new transducer make i t an ideal choice for measuring low-level pressures amidst a h i g h common-mode environment.

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~ . _ _ _ .. . . ' . ._.. . I . , -

PASSIVE ACOUSTIC MEASUREMENTS I N GEOTHERMAL WELLS

Manuel Echave Los Alamos National Laboratory

Los Alamos, NM 87545

Detect ion of f rac tu re dimensions and o r ien ta t i on of a geothermal rese rvo i r i s important f o r c rea t ing and understanding the operat ion o f a dry, ho t rock energy ex t rac t i on system. The development of downhole instrumentation. capable o f character izat ion o f hydraul ic f rac tu re systems i n high-temperature and high-pressure borehole environments provides methods of measuring the. locat ion, o r i en ta t i on nd shape o f the f racture. The downhole instrumentat ion must emphasize r e l i a b i l i t y o f measuring devices and e lec t ro - mechanical components t o funct ion proper ly a t borehole temperatures o f 250°C and pressures o f 10 000 psi .

A passive method by which acoust ic s ignals are detected and used t o "map" f rac tu res has been under intense development f o r the Hot Dry Rock Geothermal Energy Program. This method uses downhole t r i a x i a l geophone instruments t o detect acoust ic s ignals generated dur ing pressur iza t ion o r i n f l a t i o n o f the hydraul ic f rac tu re systems.

The geophones selected and u t i l i z e d are manufactured by Mark P.roducts

(Model Nos. L15AHT-4.5Ht and L15AHT-30Hz). The f i r s t model i s a 12" v e r t i c a l geophone whose natura l frequency i s 4.5 Hz; the other detector has a natura l

frequency of 30 Hz and i s used i n both the v e r t i c a l and hor izon ta l axis. These geophones were tested t o 280°C f o r several hours i n the laboratory, were

downhole f o r 30 continuous hours a t borehole temperatures of 240°C, and showed no s i g n i f i c a n t s ign o f s ignal degradation. The geophones are incorporated i n three d i s t i n c t downhol e acous ti c packages : the t r i a x i a l

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acoustic detector, the slimline t r iaxial acoustic detector, and the Precambrian vertical acoustic detector.

The t r iaxial acoustic detector is 13 f t long, weighs 325 l b s , and has an outside diameter of 5.5 i n . Four 30-Hz geophones are used i n each axis t ied i n series. The detector employs ei ther a downhole mul t ip l ex or FM multiplex instrument system. The e l e c t r o n i c s a r e housed i n a thermal- pro tec t ion system, which is composed of a controlled-environment enclosure (dewar) used i n conjunction w i t h a heat sink containing cerrobend. T h i s system greatly increases downhole operating time and allows the use o f low-temperature electronics which enhances the capability of the instrument system.

The multiplex system allows monitoring of additional pertinent data other than the geophone signals, i .e. , the internal dewar temperature, geophone orientation, and power-pack voltages (ba t te r ies ) . Borehole s lant angle i s measured and referenced t o previous we1 1 bore surveys t o provide geophone orientation.

The downhole multiplex is controlled from the surface data acquisition and control system. The program is designed t o step the downhole multiplexer by operator in i t ia t ion of keyboard command allowing the measurement of auxiliary downhole data. Upon completion o f t h i s cycle, the computer w i l l return the mu1 t i p l e x t o continuously monitor the geophone ou tpu t s .

The FM system not only provides a multiplex system b u t also enhances the signal -to-noi se ra t io and increases data frequency transmission. H i gher frequencies can be transmitted uphole w i t h o u t loss of signal information because attenuation caused by the cable only affects the magnitude of the car r ie r frequency and not the data. The FM system is also ideal for use on coaxial cab1 e.

The high-temperature slimline t r iaxial acoustic detector was primarily designed for use i n a dr i l l string. I t i s 10 f t long, weighs 150 l b s , and has an outside diameter of 3-1/4 i n . Two 30-Hz geophones are ut i l ized i n each axis and t ied i n series. A high-temperature amplifier c i r cu i t i s employed i n this package. A l l components are thermally hardened, tested t o 260°C i n the laboratory, and have been used downhole for 30 h a t temperatures of 24OOC. There was no significant s ign of signal degradation. Compensation adjustment i s made uphole on the electronics, which are placed i n an oven set for the temperatures they were expected t o encounter.

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Borehole coupling o f the t r i a x i a l and s l i m l i n e t r i a x i a l acoustic d e t e c t o r s i s achieved by means o f an arm-actuat ing dev i ce d r i v e n by a

high-temperature (275°C) dc motor. The coupling system extends an arm t o force the package against the borehole wal l . The actuat ing l inkage includes a

shear p i n t o r e l e a s e t h e extended arm should t h e motor f a i l downhole t o r e t r a c t the arm. A balanced p i s ton has been designed i n t o the actuat ing mechanism t o equalize loading i n both d i rect ions. The t o t a l force o f the arm against the borehole wal l i s about 325 lbs.

The Precambrian v e r t i c a l acoustic detector i s 22 in. long, weighs 20 lbs, and has an outside diameter o f 2-1/2 in . Four 4.5-Hz geophones are u t i l i z e d i n t h i s package; t h e y a r e t i e d i n s e r i e s . The package i s p o s i t i o n e d approximately 2000 t o 3000 f t below the surface i n grani te. Several o f these detectors are u t i l i z e d and form a Precambrian network.

Microearthquakes recorded during hydraul ic s t imulat ion experiments p r o v i d e i m p o r t a n t i n f o r m a t i o n on t h e s i z e and o r i e n t a t i o n o f a growing hydraul ic f rac tu re a t the Los Alamos National Laboratory's Fenton H i l l Hot Dry

Rock Si te. Signals recorded from the or iented downhole acoustic packages are analyzed t o determine the l oca t i on o f the microearthquakes o r events producing the signal.

The acoustic s ignals generated by a seismic source consist o f two types o f body waves. The compressional waves (P-waves) propagate p a r a l l e l t o the d i r e c t i o n o f p a r t i c l e displacement throughout the media. The transverse o r shear waves (S-waves) propagate i n the shear mode o r perpendicular t o the d i r e c t i o n of p a r t i c l e displacement. I n any given sol i d medium, compressional waves t r a v e l a t a higher v e l o c i t y than the $-waves. By knowing the medium and measuring the time delay between the a r r i v a l o f the compressional and shear

waves, distance can be measured. The po la r i za t i on d i r e c t i o n o f the i n i t i a l ( P ) wave a r r i v a l determines d i rect ion. The po la r i za t i on d i rec t i on and S-P

t ime g i ve the d i r e c t i o n and distance o f the event r e l a t i v e t o the detector.

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FLUID SAMPLER

by

Jacobo Archuleta

P.O. Box 364 Santa Crut, NM 87565

Mechanical Design Services *

ABSTRACT

This paper discusses the design changes and modif icat ions incorporated i n t o an ex i s t i ng f l u i d sampler. The new design u t i l i z e s a l l f e a t u r e s proved success fu l i n a 1975 sampler des ign and upgrades from a 200°C spec i f i ca t i on l i m i t t o permit operation a t borehole temperatures of 300°C and 10 000-psi pressure.

A downhole f l u i d sampler i s required i n geothermal operations i n obtaining i n s i t u borehole f l u i d s before they mix w i th other wellbore f l u i d s . F l u i d samples are obtained immediately upon enter ing the wellbore from a resf dent reservoi r , thereby preserving gases and d i ssol ved sol i d s i n sol u t i on. A sample t h a t i s obtained a t the wellhead a f t e r f l ash ing i s impossible t o reconst i tu te .

Evaluation o f downhole samples obtained a t Fenton H i l l , Costa Rica, E l Centro, The Geysers, and other geothermal f i e l d s indicates t h a t these f l u i d s are useful i n i nves t i ga t i on o f geothermal systems. Chemistry analysis al lows character izat ion o f reservoirs, f l uid-time studies, and assessment o f maximum

reservo i r temperature and capaci t y o f deposi t i o n o r scal i ng . The new high-temperature design requires t h a t i t 1) operates a t 300°C and 10 000 p s i i n geothermal f l u i d s ,

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2) i s able t o operate on a single-conductor wi re l ine, 3) incorporates features t o reseal b o t t l e a f t e r tak ing sample, 4) obtains a 2-a sample volume, 5 ) has less than a 3-5/8-in. too l diameter. A f l u i d sample i s ob ta ined by opening a v a l v e mounted on t h e sample

bo t t l e . A min ia ture high-temperature dc motor i s u t i l i z e d t o operate the valve stem.

The design changes required t o upgrade are as fo l lows: 1) new high-temperature motor furnished by AEI , Inc., Fu l ler ton,

2) double seals a t a l l j o in t s ; 3 ) h igh- temperature EPDM O-r ings and Bal -Seal s ob ta ined f rom Parker

4 ) rugged, pressure-balanced valve stem; 5 ) new, a l l s ta in less s tee l ex t rac t ion valves; 6) b u i l t - i n temperature wel l i n sample bo t t l e ; 7 ) quick and simple sample t rans fer disconnect; 8 ) simple uphole (surface) controls;

9) s l i c k l i n e operation mode, i.e., uses no wires. The new sampler has been f i e l d tested a t the Fenton H i l l HDR boreholes

Cal i f o rn i a.;

Indust r ies and the Bal -Seal Engineering Company, respect ively;

and a t a geothermal wel l i n the E l Centro va l ley.

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INTERPRETATION OF WELL LOGS TO SELECT PACKER SEATS I N OPEN-HOLE SECTIONS OF GEOTHERMAL WELLS

by

Ber t R. Dennis

Los Alamos, NM 87545 Los A1 amos Nat i onal Laboratory

I. INTRODUCTION

A w i re l i ne and mud logging program has been conducted i n conjunction w i th r e d r i l l i n g operations i n Well EE-3 a t the Fenton H i l l Hot Dry Rock (HDR) S i t e near Val les Caldera, New Mexico. The t ra jec to ry f o r the new bore, EE-SA, penetrated a f ractured zone st imulated from adjacent Well EE-2 and thereby establ ished hydraul ic communication. To t e s t and st imulate selected zones i n EE-3AS i n f l a t a b l e open-hole packers designed f o r high-temperature service were

used. Proper i d e n t i f i c a t i o n and se lect ion of packer seats were c ruc ia l t o the success o f the pro ject . The logging program successful ly i d e n t i f i e d f i v e competent packer seats i n s i x attempts Wirel ine temperature, ca l iper , and natura l gamma-ray logs were used i n conjunction w i th mud logs, d r i l l cut t ings, and d r i 11 i n g parameter data t o loca te f ractures , out-of -gage holes, temperature anomalies and mineral ized zones, which were avoided i n se lect ion o f the packer seats.

The Los Alamos National Laboratory has been engaged f o r the past decade i n developing technology f o r energy ex t rac t ion from hot dry rock reservoirs. As a p a r t o f the development o f a second, deeper, ho t te r reservo i r (Phase 111, f i e l d experiments are i n progress a t the HDR t e s t s i t e . The primary ob jec t ive of the f i e l d operations has been t o achieve hydraul ic communication between

Wells EE-2 and EE-3 a t depths ranging from 11 500 t o 13 200 ft. Thus co ld

water can be i n jec ted down one wel l and hot water produced a t the other wel l . The rock mass surrounding the two we l ls was st imulated w i th the i n j e c t i o n of

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la rge volumes o f water. Subsurface microseismic detectors were used t o map the microearthquakes dur ing and a f t e r the massive in ject ions. A f t e r f a i l i n g

t o establ ish a connection, EE-3 was sidetracked and r e d r i l l e d (EE-3A) on a lower t r a j e c t o r y t o i n t e r s e c t a high densi ty region i n the cloud of microseismic events surrounding EE-2 r e s u l t i n g from the l a rges t i n jec t i on , which used f i v e m i l l i o n gal lons o f f resh water.

A number o f reservo i r s t imulat ion tes ts were conducted a t various depths dur ing r e d r i l l i n g operations. Due t o the existence o f a low-pressure region a t 10 250 ft, the lower i n t e r v a l s had t o be i so la ted from t h i s zone and open-

h o l e packers were s e l e c t e d as t h e o n l y p r a c t i c a l method t o e f f e c t i v e l y s t imulate and in ter rogate the wellbore. This was accomplished w i th the use o f a recen t l y improved, open-hole3 i n f l a t a b l e packer. The h igh i n i t i a l temperature, large thermal cycles, h igh d i f f e r e n t i a l pressures, and abrasive

open-hole environment created an extremely chal lenging environment for open- hole packer operations. Packer seats had t o be selected t o avoid enlarged, fractured, incompetent, o r mechanically weak boreholes. A r e l i a b l e logging program was essential f o r successful packer operations and the rese rvo i r development and t e s t i n g program.

11. LOGGING PROGRAM

The l o g g i n g program i n c l u d e d i n t h e EE-3A d r i l l i n g p l a n sought t o i d e n t i f y and locate e f fec t i ve packer seats. Most o f the wellbore was assumed t o be unsuitable due t o one or more o f the fo l lowing condit ions: oversized,

i r r e g u l a r broken-out o r washed-out bore; open f ractures i n te rsec t i ng the bore; m i neral -f i 1 1 ed fractures ; and j o i nted o r weak rock more suscepti b l e t o f r a c t u r i n g than the targeted i n j e c t i o n zone. Potent ia l packer seats were located by using mud logs, temperature logs, and c a l i p e r logs. Open-hole and through-dri 11 -pipe gamma-ray/col l a r - l oca to r logs were used t o co r re la te d r i 11 pipe and open-hole w i re l i ne depths.

111. WIRELINE LOGGING AND PROCEDURES

A 7-conductor, t e t r a f 1 uoroethyl ene (TFE 1 Tef 1 on-i nsul ated 1 oggi ng cab1 e and cablehead rated f o r continuous service a t 320°C were used t o run the Los A1 amos p r o j e c t 1 oggi ng sondes. Pressure contro l equipment f o r the

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high-temperature logging cable was l i m i t e d t o 1000 psig. A casing c o l l a r l oca to r was run i n conjunction w i th other sondes f o r depth ca l i b ra t i on .

A commercial " s l im hole" gamma-ray/col l a r l oca to r provided a through-dr i l l -p ipe l og i n a d r i l l s t r i n g cooled w i th low f low r a t e c i r cu la t i on .

The temperature sonde uses a thermistor probe w i t h high accuracy and resolut ion. It i s r e a d i l y f ie lded, re l i ab le , and more e a s i l y replaced than other sondes. Therefore, i t was run before running other logging sondes. Cable tension and t o o l turnaround were monitored c a r e f u l l y t o assure hole condi t ions were su i tab le f o r the ca l i pe r logging t o fo l low. Surveys were run a t 60 t o 150 f t /min both i n t o and out o f the well . Depths were corrected f o r thermal l a g time and cable s t re t ch (turnaround).

Temperature surveys were run i n Well EE-3A preceding and fo l lowing each packer experiment. Anomalies and va r ia t i ons from the background temperature gradient were used t o i n f e r f rac tu re i n l e t s l o u t l e t s w i t h i n k10 ft. More

precise l oca t i on o f fractures was of ten precluded by the high pressures t h a t prevented logging during i n j e c t i o n or ea r l y shut-in. The packer conf igurat ion prevented logging below it. Venting and c i r c u l a t i o n o f the wel l was required before removal, and t h i s resul ted i n a smearing o f f l u i d entrances and made i t d i f f i c u l t t o determine the f rac tu re locations.

The Los Alamos ca l i pe r t o o l i s a 3-independent-arm too l configured t o measure h o l e diameters f rom 5 t o 14 i n . Mechanical l i n k a g e , magnet ic couplings , and high-temperature r o t a r y potentiometers are used t o convert borehole radius t o an e l e c t r o n i c a l l y measured output. The sonde was run w i t h t h e arms r e t r a c t e d . They were extended t o l o g o u t over t h e i n t e r v a l o f i n t e r e s t and then ret racted f o r removal. Logging speeds var ied from 20 t o 40 f t / m i n . Pre-1 og and post-1 og ca l i b r a t i ons were made t o ca l cu l ate correct ions f o r the c a l i p e r pad wear, which?was s i g n i f i c a n t on runs o f over 2000 ft. The too l was run w i th two bow centra l izers s t raddl ing the measuring arms. A s l i p and s t i c k movement of the t o o l was indicated by c a l i p e r l o g q u a l i t y below 12 600 ft.

Accurate c a l i p e r logs were required t o se lect packer seats. Over-extension o f the high-temperature design i n f l a t a b l e packer element ( i n the range o f 9.5-in. diam) made the element susceptible t o rupture. Washouts,

breakouts, o r ledges which c o u l d e a s i l y go undetected u s i n g a s i n g l e or dual-arm ca l i pe r can also rupture the element.

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A Geiger detector, gamma-ray sonde was run i n the open hole o f EE-3A t o t i e the natural gamma-ray depth signature t o the p r o j e c t ' s w i r e l i n e depths. The e lect ron ics for the too l are thermally protected i n a dewar housing w i t h a cerrobend heat sink. The too l operates a t temperatures o f 300°C f o r more than 6 h. The gamma-ray signature obtained was r e a d i l y corre la ted w i t h signatures obtained w i th the commercial through-dr i l l -p ipe log. Most logs were run a t 60 t o 80 ft /min. Logging speeds as low as 40 f t /m in were required t o obtain a good repeat signature w i th the dewared too l .

I V . RESULTS OF THE LOGGING PROGRAM

The logging program provided input t o the successful packer operations and a lso added s i g n i f i c a n t l y t o the rese rvo i r descr ip t ion process, complementing i n j e c t i o n and t race r data. Results t h a t contr ibuted t o the rese rvo i r descr ip t ion included depth co r re la t i on o f d r i l l i n g data w i t h w i r e l i n e data, l oca t i on o f ac t i ve f ractures, m i n e r a l - f i l l e d fractures, and f o l i a t i o n and formation changes.

Depth measurements made on various runs using the same w i r e l i n e var ied less than 4 ft. Depths measured using d i f f e r e n t w i re l i nes var ied as much as 20 ft. Nhen working w i t h i n 600 ft o f the bottom o f the hole, tag bottom

depths were used successful ly t o make the d r i l l p ipe/wi re l ine depth correct ion. A logging run was required f o r each sonde run since mul t ip lex ing

equipment f o r the Los Alamos open-hole logging too l s (now under development) was not avai lable. Where accurate packer depths were required, an open-hole

gamma-ray l o g was run on the w i r e l i n e cu r ren t l y i n use t o corre la te w i t h a through-dr i l l -p ipe gamma-ray log.

The EE-3A logging program was c ruc ia l i n se lect ion o f packer seats f o r the reservo i r t e s t i n g program. The mud logging program provided we l l s i t e i n p u t t o focus the ca l i pe r logging on regions w i th good po ten t i a l packer

seats. The 3-arm ca l i pe r l og was needed t o e l iminate sections o f bore t h a t were too large for the high-temperature packer element. Temperature logs

provided s u f f i c i e n t l y accurate l oca t i on o f f ractures t o se lect packer seats. The logging program has also contr ibuted t o the understanding o f rese rvo i r

structure, which a t t h i s p o i n t i s i n good agreement w i th other rese rvo i r data. The importance o f m u l t i p l e arm ca l i pe r logging and good w i r e l i n e depth

correct ions was demonstrated dur ing these operations. High-temperature

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wireline logging has been shown t o be a useful investigative tool i n granit ic rock. A 6-arm hot-hole caliper, a high-temperature multiplexing system, and high-pressure we1 1 control equipment for large-diameter hot-hole wire1 ines are needed t o make the techniques described commercially viable. A method t o eliminate the severe st ick-slip movement of the caliper and other sondes i n the inclined, abrasive wellbores a t Fenton Hill would make the caliper and open-hole packers a powerful and complementary we1 1 bore evaluation system.

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Description Acoustic W i ndow Ampli f fer Operational Amplifier Operational Cable Armored Wireline Cable Armored Wireline Cablehead Cablehead Boot Connector Connector--Mi crominiature Connector--Cablehead Capacitor Capacitor Dewar Detonator Fi ri ng Module High-Temperature Grease Gei ger-Mull er Tube Heat Pipe Heat Sink Mo tor--dc Motor--ac oi 1 o i 1 O-Ri ng O-Ri ng Printed Circuit Board Printed Circuit Connector Relay DPDT Re1 ief Valve Resistor Rotary Transformer Slip Ring Slip Ring Assembly High-Temperature Solder Hi gh-Temperature Tape Transducers

Acce 1 erometer Accelerometer Accelerometer Cable Acoustic Crystal Acoustic Crystal Acous ti c Crystal Coll a r Locator Geophone Magnetometer Potenti meter Pressure Transducer Reed Relay Thermistor

Volta e Regulator Wire ?lookup

-

HIGH-TEMPERATURE COMPONENTS

Manufacturer 10s Alamos Harris Electronics Burr -Brown Rochester Corporation Vector Corporation Los Alamos Kemlon Products Gu 1 ton Industries ITT Cannon Reynolds Industries American Techni cal Ceramics Corning Glass Horks Vacuum Barrier Reynolds Industries Rey n 01 d s I nd us t r i es E.I. DuPont Company, Inc. Harshaw/Fi 1 trol Los Alamos Los Alamos American Electronics, Inc. American Electronics, Inc. Dow Corning E.I. DuPont Company, Inc. Parker Seal Bal Seal Circuit Shop AMP Teledyne Lee Company Allen Bradley Ceramic Magnetics Corning Glass Norks Los Alamos Mu1 t icore Solder Boyd Industrial Rubber

BBN Instruments Endevco 8BN Instruments C hanne 1 Industries Special ties Engineering Keramos , Inc. Gearhart Mark Products Humph r ey L i t t o n Potentiometer Bell & Howell/CEC Division Ham1 i n Conax Corporation White Technology Standard Wire and Cable

Type I F € Teflon 2600-1 OPA 11 HT TFE Teflon PFE Teflon 81Y210200 KN-34 BL06-20-16-UHR MT B 1 178-7439 100B510KAW500 CHT-2A3258SP C-1428 6A RP84 FS20 Krytox 61000-17TL Methanol 81Y210297 AEI17DG2 AE17JG2 710 Krytox E962-85-SIZE IS-55-SIZE Polyomit GIN 139497 3-330808-8 412H PRRA-1875040L Metal F i l m C2050 MaCor Ceramic 8 1 Y 2 104 18 HMP Alloy 22 Gaae KaptonlTeflon

BK424 7705-200 070905 C5500 L i t h i u m Niobate K-350 05-2010 L15AHT FD17-0201-1 6119 CEC-1000-09 MSRR-2CD \

T3 C8000-15 TFE Teflon

Temp Rate ('C) m 290 250

,300 260 >300 >300 300 290

,300 290 200 275 27 5 200 260 200 100 80

275 260 275 260

>300 >300 300 300 275 275 300 275

>300 300 300 260

300 260 300 200 260 220 250 260 275 260 ,300

300 ,300 290 >300

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MANUFACTURERS OF HIGH-TEMPERATURE COMPONENTS

A1 l e n Bradley Company 1201 S. Second Street Milwaukee, H I 53204 (414) 671-2000

American Electronics, Inc. 1600 E. Valencia Dr ive Ful ler ton, CA 92631 ( 714 1 871-3020

American Technical Ceramics 1 Norden Lane Huntington Station, NY 11746 (516) 217-9600

AMP, Inc. P.O. Box 3608 Harrisburg, PA 17105 ( 717) 986-5714

Bal -Seal 620 West Warner Santa Ana, CA 92707 (714) 557-5192

BBN Instruments Corporation 506 Moulton Street Cambridge, MA 02138 (617) 491-0091

Boyd I n d u s t r i a l Rubber 3420 West Whitton Phoenix, A2 85017

Burr-Brown Research Corporation 6730 S. Tucson Blvd Tucson, A2 85706 (602) 746-1111

CEC Instrument D i v i s i o n 325 Halstead Street P.O. Bin 7087 Pasadena, CA 91109-7087 (213) 351-4241

Ceramic Magnetics, Inc. 876 F a i r f i e l d Road F a i r f i e l d , NJ 07006

Channel Indust r ies 839 Ward Drive Box 3680 Santa Barbara, CA 93130

(201) 227-4222

(805) 967-0171

Conax Corporation 2300 Walden Avenue Buffalo, NY 14225 (716) 684-4500

Corning Glass Works 3900 Elect ron ic Dr ive Annex RND Bui ld ing Raleigh, NC 27605 (919) 876-1100

Dow Corn1 ng Department A0021 P.O. Box 1767 Midland, M I 48640 (517) 496-4000

E.I. DuPont Company, Inc. Barley M i l l Plaza Wilmington, DE 19898 ( 302) 992-2404

Endevco 30700 Rancho Vie jo Road San Juan Capistrano, CA 92675 (714 1 493-8181

Gearhart Industr ies, Inc. P.O. Box 1936 Ft. Worth, TX 76101

Gul ton Indust r ies Servoni c D i v i s i o n 1644 W h i t t i e r Avenue Costa Mesa, CA 92627 (714) 642-2400

(817) 551-4155

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Hamlin, Inc. Lake and Grove Street Lake M i l l s , W I 53551 (414) 648-2361

Har r i s Semiconductor Anal og Products D i v i s i o n P.O. Box 883 Melbourne, FL 32901-0101 (305) 727-4000

Harshaw/Fi 1 t r o l 6801 Cochran Road Solon, OH 44139 (216) 248-7400

Humphrey, Inc. 9212-6 Balboa Avenue San Diego, CA 92123 (714) 565-6631

I T T Cannon 105506 Tal b e r t Fountain Valley, CA 92708 (714) 964-7400

Kemlon Products P.O. Box 14666 Houston, TX 77021 (713) 747-5020

Keramos , Inc. Lizton, I N 46149 (317 ) 994-5194

Lee Company Westbrook, CN 06498 (203) 399-6281

L i t t o n Potentiometer D iv i s ion 750 South Ful ton Avenue P.O. Box 539 M t . Vernon, NY 10551-0539 (914) 664-7733

Mark Products 10507 King hurs t D r i ve Houston, TX 77099 (713) 498-0600

Mu1 ti core Solder Cantiague Rock Road Westbury, NY 11590 (516) 334-7997

Parker Seal 2360 Palumbo Dr ive P.O. Box 11751 Lexington, K Y 40512

Reynolds Indust r ies P.O. Box 1170 Marina Del Rey, CA 90291 (213) 823-5491

Rochester Corporati on P.O. Box 312 Culpeper, VA 22701 (703) 825-2111

Speci a1 ti es Engi neer i ng M i lp i t as , CA 95035 (408) 946-9779

Standard Wire & Cable 2345-6 A1 aska Avenue E l Segundo, CA 90245 (213) 973-2345

Teledyne Re1 ays 12525 Daphne Avenue Hawthorne, CA 90250 (213) 777-0077

Vacuum B a r r i e r P.O. Box 529 Woburn, MA 01801 (617) 933-3570

Vector Corporati on 555 I n d u s t r i a l Road Sugar Land, TX 77478 (713) 491-9196

Nhi te Technology 4246 E. Wood Street Phoenix, AZ 85040 (602) 437-1520

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ATTEN DE ES

Gerald C. Adams Robert Backus Ceramaseal CEC, Inc. P.O. Box 25 325 Halstead St ree t New Lebanon Center, NY 12126 Pasadena, CA 91109 (518) 794-7800 Ext 270

Ross 0. Barnes James H. Addison, Jr. Un ivers i ty o f Washington E.I. DuPont de Nemours School o f Oceanography Savannah River Laboratory, 773-A Seatt le, WA 98195 Aiken, SC 29808 (206) 543-5129 FTS 239-2649

R, R. Beasley Sandia National Laboratories P.O. Box 5800

Daniel P. Aeschliman Sandi a National Laboratories P.O. Box 5800 Org 6257 Org 6256 Albuquerque, NM 87185 Albuquerque, NM 87185 (505) 846-0576 Kei r Becker

Ne i l P. Albaugh 4600 Rickenbacker , Burr-Brown Corporation Miami, FL 33149 Box 11400 (305) 361-4661 Tucson, AZ 85734 (602) 746-7216 Paul Bennett

Mark Amarandos P.O. Box 42800 Har r i s Corporati on Houston, TX 77242 1503 S. Coast Dr ive (713) 496-8159 Sui te 320 Costa Mesa, CA 92626 C y r i l Berg

Ot is R. Anderson UL Sperry Sun 2659 Hodges Bend C i r c l e Sugar Land, TX 77479 (713) 980-1611 Eugene P. Binnal l

Lawrence Berkeley Laboratory Roger Anderson 1 Cyclotron Road Lamont-Doherty Geological Observatory Bldg 50B/Rm 4235 Pal i sades, NY 10964 Berkeley, CA 94720

Stanley M. Angel Lawrence L i vermore Laboratory P.O. BOX 808 L-325 Livermore, CA 94551 4039 Wyne Street

Un ivers i ty o f Miami

Welex-Halliburton

Whit taker/Electronic Resources 100 E. Tujunga Avenue Burbank, CA 91502 (818 1 843-5770

FTS 451-6536

Lou Birdsong Downhol e Technology

Houston, TX 77017 ( 713 643-3374

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Russel 1 B1 anton Vacuum Barrier Corporati on 4 Barten Lane P.O. Box 529 Woburn, MA 01801

Jack G . Burgen Gearhart Industries, Inc. P.O. Box 1936 F t . Worth, TX 76101 (817) 551-4141

Ray Carey Gearhart Industries, Inc. P.O. Box 1936 F t . Worth, TX 76101 (817) 293-1300

C. Carson Sandia National Laboratories P.O. Box 5800 Org 6241 A1 buquerque , NM 87185

J. E. Chapman Schl umberger We1 1 Services P.O. Box A Rosharon, TX 77583 (713) 431-0254

Duane C1 emmer U.S. Microtek Components 1144 Penrose Street Sun Valley, CA 91352 (818) 767-6770

Fredrick G. Clutsom U. S. Geological Survey BO x 2 5 04 6/MS -97 9 Denver, CO 80225 (303) 236-7784

Tom Coles Custom Electronics, h c . 1311 Antoine Sui te 107 Houston, TX 77055 (713) 686-4874

- Bryan Conant Burr-Brown P.O. Box 11400 International Airport Industrial Park Tucson, AZ 87534

John Conaway Los A1 amos National Laboratory

Los Alamos, NM 87545 P .O. BOX 1662/MS-C335

(505) 667-8476

A. P. Conner White Technology, Inc. 4246 E. Wood S t r ee t Phoenix, AZ 85040

Joe A. Coquat CRC Wireline, Inc. P.O. Box 534024 Grand Prairie, TX 75053-4024

(602) 437-1520

(214) 988-8200

Joseph Cri tes Eastman Whipstock P.O. Box 14609 Houston, TX 77021 (713) 741-2200

Michael W. Day KD Components, Inc. 3016 S. Orange Avenue Santa Ana, CA 92707 (714) 545-7108

Ted Delong Develco, Inc. 404 Tasman Drive Sunnyvale, CA 94089

Ron Demcko Corning Electronics 3900 Electronics Drive Raleigh, NC 27604 ( 919) 878-6224

(408) 734-5700 E x t 261

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Warren D. Dunham Schonstedt Instrument Company 1775 Wiehle Avenue Reston, VA 220,90 ( 703 471-1050

Joseph J. Durapan Schl umberger 500 Gulf Freeway Houston, TX 77252-2175 (713) 928-4319

Gordon Edge U. S. M i crotek Components 11144 Penrose Street Sun Valley, CA 91352 (818) 767-6770

Tom Elsby White Techno1 ogy , Inc. 4246 E. Wood Street Phoeniz, AZ 85040

Richard Fenster Los A1 amos National Laboratory P.O. BOX 1663/MS-J900 Los Alamos, NM 87545 FTS 575-3812

Conrad F ink Hot Hole Instruments 2346-B 35th Street Los Alamos, N M 87544 ( 505 ) 672-3403

Randle Ford AMF Scient i f ic Drilling P.O. Box 808 Houston, TX 77001 (713) 799-5510

Loye Frazier Schl umberger 500 G u l f Freeway Houston, TX 77023 (713 1 928-4459

A1 Garshick BIN Cable Systems, Inc. 65 Bay Street Boston, MA 02125 ( 617) 265-2101

Richard L. Hack PDA Engineering 1560 Brookhollow Drive Santa Ana, CA 92705 ( 714) 556-2800

John Haessly Schl umberger 500 G u l f Freeway Houston, TX 77023 (713) 928-4735

S. E. Haggard Mark Products, Inc. 10507 Kinghurst Drive Houston, TX 77099 (713 498-0600

James S . Hall Schl umberger 500 Gulf Freeway Houston, TX 77023 (713) 928-4391

A r t h u r S . Halpenny Halpen Engineering, Inc. 625 Parsons Street East Aurora, NY 14052

Ben Ham Endevco 9004 Menaul N .E. Albuquerque, N M 87112 (505 1 292-8990

( 716 ) 652-3434

Ara Harootion Electronic Resources 100 E. Tujunga Burbank, CA 91502 (818) 843-5770

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Bond Herten J o i n t Oceanography I n s t i t u t e 1755 Massachusetts Avenue Sui te 800 Washington, DC 20036

T. X. Ho Chevron O i l F i e l d Research Company P.O. Box 446 La Habra, CA 90631 (213) 694-7431

Jacques Holenka Schl umberger 500 Gulf Freeway Houston, TX 77023 ( 713) 928-8605

(202) 232-3900

Chuck Hol1 ingsworth Har r is Corporation 11217 Morolco Road N.E. Albuquerque, NM 87111 ( 505) 888-0800

Jim Hudson U. S. Geological Survey 505 Marquette A1 buquerque, NM 87102 (505) 471-5932

Robert W. Hu l l U.S. Geological Survey 345 M i ddl e f i e l d Road

Menlo Park, CA 94061 MS-427

(415) 323-8111 Ext 2979

W. C. Huth Sandia National Laboratories P.O. Box 5800 Org 1540 Albuquerque, NM 87185 ( 505 1 844-3690

Gregory Jarczyk Har r is Corporation 1717 E. Morten Sui te 250 Phoenix, AZ 85020 (602) 870-0080

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Mi les F. Jaroska Schl umberger 14910 A i rl i n e Road P.O. Box Drawer A Rosharon, TX 77583 (713) 431-0282

Wade Johnson Dresser A t 1 as P.O. Box 1407 Houston, TX 77251 ( 7 13 972-4783

Yu j i Kanaori Los A1 amos National Laboratory P.O. Box 1663/MS-J979 Los Alamos, NM 87545 (505) 667-1199

J. R. Kelsey Sandia National Laboratories P.O. Box 5800 A1 buquerque, NM 87185 ( 505) 844-6968

John P. Kennelly, Jr. U.S. Geological Survey 345 M i ddl e f i e l d Road/MS-923 Menlo Park, CA 94025 (415) 323-8111 Ext 2386

George L. Kerber Squire-Whitehouse Corporation 9940 Barnes Canyon Road San Diego, CA 92121 (619) 587-9633

Randal 1 K. K i rschman P.O. Box 391716 Mountain View, CA 94039 (415) 369-7531

Dona1 d Koel f ch J o i n t Oceanography I n s t i t u t e 1755 Massachusetts Avenue Sui te 800 Washington, DC 20036 (202) 232-3900

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A1 f red Krampe Schl umberger-Doll Old Quarry Road Ridgefield, CT 06877 (203 431-5437

E r i c W. Krieger NWEF K i r t l a n d AFB Albuquerque, NM 87117-5000

M i ch i o Kuriyagawa Los Alamos National Laboratory P.O. BOX 1663/MS-J981 Los Alamos, NM 87545 (505) 667-1916

Kenichi Kusunoki NED0 Higashi-Ikebukureo 1-1-3 Toshimaku, Tokyo 170 Japan 03-981 -151 1

James La l i cke r Great Guns Logging D i g i t a l D i v i s i o n 9810-A East 58th St reet Tulsa, OK 74146 (918 252-5416

Markus Langseth J o i n t Oceanography I n s t i t u t e 1755 Massachusetts Avenue Sui te 800 Washington , DC 20036

Roger Larson Jo in t Oceanography I n s t i t u t 1755 Massachusetts Avenue Sui te 800 Washington, DC 20036 (202) 232-3900

L a r r y Le i s ing Anadri 11 -Schl 200 Macco Blv Sugar Land, TX 77478

(202 1 232-3900

( 713 ) 240-4949

Peter Leonhardt Endevco 30700 Rancho Vie jo Road San Juan Capistrano, CA 92675 ( 714 1 493-8181

Marshal 1 Levine Nemar #3 Grapevalley Park Melvern, PA 19355 (215) 251-0118

Thomas M. L i t t l e Schl umberger P.O. Box 2175 Houston, TX 77252-2175 ( 713) 928-4396

Dennis A. Lynch Dresser A t 1 as 2421-A Portola Road Ventura, CA 93003 (805 1 642-7774

Michael J. Lynch Ha l l i bu r ton Services P.O. BOX 1431/MS-0450 Duncan, OK 73536 (405 ) 251-3607

C1 aude Mabi 1 e Ocean D r i 1 1 i ng Program P.O. Drawer GK College Station, TX 78743

Carl Mar t in Welex-Hall i bu r ton P.O. Box 42800 Houston, TX 77242 (713) 496-8307

Mark Mathews Los Alamos National Laboratory P.O. BOX 1663/MS-C335 Los Alamos, NM 87545 (505) 667-8476

(405) 845-6150

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John Mattes Whi t t a k e r Corporati on E lec t ron ic Resources D iv i s ion 100 East Tultunga Avenue Burbank, CA 91502 (818) 843-5770

Robert Maul d i n Whi t t a k e r Corporation E lec t ron ic Resources D iv i s ion 100 East Tultunga Avenue Burbank, CA 91502 (818) 843-5770

Gene Mayes Bel 1 Petroleum Systems 5144 S.E. Loop 820 Ft. Worth, TX 76140 (817) 478-1171

Russel 1 McDuff School o f Oceanography Un ivers i ty of Washington MS WB-10 Seatt le, WA 98195 ( 206 ) 545-1947

Daniel McMahon Endevco 30700 Rancho Vie jo Road San Juan Capistrano, CA 92675 (714) 493-8181

Lloyd E. M i l l e r Har r is Semiconductor P.O. Box 883 MS 4-59-03 Melbourne, FL 32907 (305) 729-5261

Dr. Melvin M i l l e r Nemar #3 Grapevalley Park Melvern, PA 19355 (215) 251-0118

Richard G. M i l l e r Gearhart Indust r ies, Inc. P.O. Box 1936 Ft . Worth, TX 76101 (817) 293-1300 Ext 5818

Thomas H. Moses, Jr. U .S . Geol og i ca l Survey 345 Midd le f i e ld Road MS-923 Menlo Park, CA 94025 (415) 323-8111

Demmie L. Mosley O i 1 We1 1 Per forators P.O. Box 399 M i l l s , WY 82644 (307) 473-9270

Richard Murphy NL McCullough P.O. Box 60060 Houston, t X 77205

Nobuo Nagata N ED0 Higashi -1kebukuro 1-1-3 Toshimaku, Tokyo 170 Japan 03-981-1511

Walt Niewierski Har r i s Semiconductor P.O. Box 883/MS 59-03 Melbourne, FL 32907 (305) 729-5261

Ron O l i ve r Los A1 amos National Laboratory P.O. Box 1663/MS-J900 Los Alamos, NM 87545 FTS 575-3415

Barry W. Palmer B I C C Pyrotenax LTD 523 North B e l t Su i te 540 Houston, TX 77060 (713) 591-1551

Steven E. Palmer Squire-Whi tehouse Corporation 9940 Barnes Canyon Road San Diego, CA 92121 ( 619 ) 587-9633

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Janet E. Par iso Un ivers i ty o f Washington WB-10 School of Oceanography Seatt le, WA 98112 ( 206) 543-8542

Bjorn Paulsson Chevron O i 1 Fie1 d Research Company P.O. Box 446 La Habra, CA 90631 (213) 694-7161

M i t c h e l l F. Peterson Chevron Of 1 F i e l d Research Company P.O. Box 446 La Habra, CA 90631

John Petro Petrophysi ca l Services 1500 Salado Avenue Mountain View, CA 94043 (415) 960-0964

(213 1 694-9319

Wil l iam H. P f e i f e r PDA Engi neer i ng 1560 Brookhollow Drive Santa Ana, CA 92705 (714 1 556-2800

George Ph i l p o t The Rochester Corporation Culpeper, VA 22701

Ala in P. P o t t i e r Schl umberger 500 Gul f Freeway Houston, TX 77023 (713 1 928-4413

P h i l i p Questad I C 1 10301 Willows Road Redmond, MA 98052

James Rannel s U.S. Department o f Energy Geothermal and Hydropower Technologies D iv i s ion Washington , DC 20585

(206 882-3100

J. A. Rochelle Environmental Science 3030 McKinney Dallas, TX 75204 (214) 871-2210

Charles C. Ross Squire-Whi tehouse Corporation 9940 Barnes Canyon Road Sal? Diego, CA 92121 (619) 587-9633

Raymond Rowzee Welex-Hal1 i burton P.O. Box 42000 Houston, t X 77242 (713) 496-8159

Mathew Sal i sbury Dal housi e Un ivers i ty Center f o r Marine Geology Hal i fax, Nova Scot ia B3H3J5

Chet Sandberg Raychem 300 Const i tu t ion Dr ive Menlo Park, CA 94025 (415) 361-4770

N. Harold Sanders Dresser At las R&E P.O. BOX 1407 DC-1 Houston, TX 77251 (713) 972-6157

Fred Sawin Vector-Schl umberger 555 I n d u s t r i a l Road Sugar Land, TX 77478

George E. Schal ler Ceramic Magnetics, Inc. 87 F a i r f i e l d Road F a i r f i e l d , NJ 07006

(902 424-6531

( 713 ) 771-3132

(201) 227-4422

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John Schauffe B I C C Pyrotenax LTD 523 North B e l t Su i te 540 Houston, TX 77060 (713) 591-1551

P. Schl umberger P.O. Box 2175 Mail Drop 3A Houston, TX 77252-2175

Run M. Shively Chevron O i 1 F i e l d Research Company P.O. Box 446 La Habra, CA 90631 (213) 694-7195

Bob Sloan Schl umberger Nuclear Department 500 Gulf Freeway Houston, TX 77023 (713) 928-4872

Tony Small We1 ex P.O. Box 42800 Houston, TX 77242 ( 713) 496-8169

Ray D. Solbau LBL #1 Cyclotron Road Berkeley, CA 94720 ( 4 15 ) 486-4438

Jimmy D. Starnes Gearhart Industr ies, Inc. P.O. Box 1936 Ft . Worth, TX 76101 (817) 293-1300

Francis G. S teh l i Dosecc, InC. 601 E l m St reet Norman, OK 73019 (405) 325-6111

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Ken Stephens U. S. Geological Survey 505 Marquette A1 buquerque , NM 87102 (505) 474-5932

0. L. Stone Schl umberger P.O. Box 2175 Houston, TX 77252 ( 713 1 928-4393

Char l ie Suh Be l l Petroleum Systems 5144 S.E:Loop 820 Ft. Worth, TX 76140 ( 817) 478-117 1

George Tennyson U.S. Department o f Energy A1 buquerque Operations O f f i c e P.O. Box 5400 _.

Albuquerque, NM 87115

Raymond W. Teys AMF S c i e n t i f i c D r i l l i n g P.O. Box 808 Houston, TX 77001 (713) 799-5475

Lewis Thompson Vacuum Bar r i e r Corporation 4 Barten Lane Woburn, MA 01801 (617) 933-3570

Ron Toms U.S. Department o f Energy Geothermal and Hydropower Techno1 ogies D iv i s ion Washington, DC 20585

V1 adimi r Vaynshteyn Schl umberger 14910 A i r l i n e Road Rosharon, TX 77583 (713) 431-0213

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C. L. Veach CRC Wireline, Inc. P.O. Box 534024 Grand Prairie, TX 75053-4024 (214 1 988-8200

Anthony Veneruso F1 opetrol Johnston Schl umberger P.0. Box 36369 Houston, TX 77236-6369 (713) 240-7000

R. Von Herzen WHO1 Woods Hole, MA 02543 (617) 548-1400

James Waggoner Schl umberger 500 G u l f Freeway Houston, TX 77023

Ralph Mal kingstick Great Guns Logging Digi ta l Division 9810-A East 58th Street Tulsa, OK 74146

Raymond H . Mal 1 ace, Jr U.S. Department o f Energy 1000 Independence Avenue S.H. Washing ton, DC 20585 (202 252-8082

(918) 252-5416

Charles A. Weisleder NWEF Kirtland AFB Albuquerque, NM 87117-5000 I

(505) 844-9021

Billy F. Wilson Dresser Atlas P.O. Box 1407 Houston, TX 77251 (713) 972-6418

Piero Wolk National K Works 1717 Brittemoore Road Houston, TX 77043

David M. Yates Hot Hole Instruments 2059-B 41st Street Los Alamos, N M 87544 ( 505 672-3403

Matthew We1 ch Nova Marketing 9207 Country Creek Houston, TX 77036 ( 713 ) 988-6082

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