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DOE/NV/11718--591
Nevada EnvironmentalRestorationDivision
CompletionReport forWell ER-EC-2A
March 2002
DISCLAIMER STATEMENT
Reference herein to any specific commercial product, process, or service by tradename, trademark, manufacturer, or otherwise, does not necessarily constitute orimply its endorsement, recommendation, or favoring by the U.S. Government orany agency thereof or its contractors or subcontractors.
AVAILABILITY STATEMENT
Available to the public, in paper, from–
U.S. Department of CommerceNational Technical Information Service5285 Port Royal RoadSpringfield, VA, 22161-0002Telephone: 800.553.6847Fax: 703.605.6900E-mail: orders@ntis.fedworld.govOnline ordering: http://www.ntis.gov/ordering.htm
Available electronically at http://www.doe.gov/bridge.
Available for a processing fee to U.S. Department of Energy and its contractors,in paper, from–
U.S. Department of EnergyOffice of Scientific and Technical InformationP.O. Box 62Oak Ridge, TN 37831-0062Telephone: 865.576.8401Fax: 865.576.5728E-mail: reports@adonis.osti.gov
DOE/NV/11718--591
Completion Report forWell ER-EC-2A
Prepared for:U.S. Department of Energy
National Nuclear Security AdministrationNevada Operations Office
Las Vegas, Nevada
Prepared by:Bechtel Nevada
Geological and Hydrological ServicesLas Vegas, NV
March 2002
This work was supported by the U.S. Department of Energy, National Nuclear Security Administration
Nevada Operations Office, under Contract No. DE-AC08-96NV11718.
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v
Completion Report for Well ER-EC-2ADOE/NV/11718--591
ABSTRACT
Well ER-EC-2A was drilled for the U.S. Department of Energy, National Nuclear Security
Administration Nevada Operations Office, in support of the Nevada Environmental Restoration
Project at the Nevada Test Site, Nye County, Nevada. This well was drilled in January and
February of 2000 as part of a hydrogeologic investigation program in the Pahute Mesa - Oasis
Valley region just west of the Nevada Test Site. A 44.5-centimeter surface hole was drilled and
cased off to a depth of 412.9 meters below the surface. The hole diameter was then decreased to
31.1 centimeters for drilling to a total depth of 1,516.1 meters.
One completion string with three isolated slotted intervals was installed in the well. A
preliminary composite, static water level was measured at the depth of 228.0 meters,
approximately two months after installation of the completion string.
Detailed lithologic descriptions with preliminary stratigraphic assignments are included in this
report. These are based on composite drill cuttings collected every 3 meters, and 81 sidewall
samples taken at various depths below 212 meters, supplemented by geophysical log data.
Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on
30 samples. The well was collared in rhyolite lava and penetrated Tertiary-age lava and tuff of
the Volcanics of Fortymile Canyon and the Timber Mountain Group. The preliminary geologic
interpretation of borehole data indicates that this well was drilled within the margins of the
buried Rainier Mesa and Ammonia Tanks calderas, and that caldera collapse in this area was
deeper than expected, resulting in a section of Volcanics of Fortymile Canyon (caldera-filling
deposit) that is much thicker than expected.
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vii
Table of Contents
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
List of Acronyms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1 Project Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.3 Project Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
1.4 Project Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
2.0 Drilling Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 Drilling History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.3 Drilling Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
2.4 Fluid Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
3.0 Geologic Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2 Collection of Drill Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.3 Sidewall Core Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.4 Sample Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.5 Geophysical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
4.0 Geology and Hydrogeology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.2 Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.2.1 Stratigraphy and Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.2.2 Alteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.3 Predicted Versus Actual Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.4 Hydrogeology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Table of Contents (Continued)
viii
5.0 Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.1 Preliminary Water-Level Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.2 Water Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.3 Preliminary Flow Meter Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
5.4 Preliminary Groundwater Characterization Samples . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
6.0 Precompletion and Open-Hole Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
7.0 Well Completion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.2 Well Completion Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.2.1 Proposed Completion Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.2.2 As-Built Completion Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
7.2.3 Rationale for Differences between Actual and Proposed Well Design . . . . . . 7-6
7.3 Well Completion Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
8.0 Actual versus Planned Costs and Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
9.0 Summary, Recommendations, and Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
9.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
9.2 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
9.3 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
10.0 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
Appendix A - Drilling Data
A-1 Drilling Parameter Logs for Well ER-EC-2A
A-2 Casing Data for Well ER-EC-2A
A-3 Well ER-EC-2A Drilling Fluids and Cement Composition
Appendix B - Well ER-EC-2A Fluid Management Data
Well ER-EC-2A Fluid Disposition Reporting Form
Preliminary Analytical Results for Fluid Management Samples from Well ER-EC-2A
Appendix C - Preliminary Detailed Lithologic Log for Well ER-EC-2A
Appendix D - Geophysical Logs Run in Well ER-EC-2A
Distribution List
ix
List of Figures
Number Title Page
1-1 Reference Map Showing Location of Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2-1 Drill Site Configuration for Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2-2 Well ER-EC-2A Drilling and Completion History . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
4-1 Map of Pahute Mesa - Oasis Valley Area Showing Theorized Locations of
Caldera Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-34-2 Surface Geologic Map of the Well ER-EC-2A Site . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4-3 Geology and Hydrogeology of Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
4-4 Preliminary Geologic Cross Section A-A’ Through Well ER-EC-2A . . . . . . . . . . . . 4-12
4-5 Predicted and Actual Stratigraphy at Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . 4-14
4-6 Preliminary Hydrogeologic Cross Section B-B’ Through Well ER-EC-2A . . . . . . . . 4-17
7-1 As-built Completion Schematic for Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
7-2 Wellhead Diagram for Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
8-1 Planned versus Actual Construction Progress for Well ER-EC-2A . . . . . . . . . . . . . . . 8-2
8-2 Planned versus Actual Cost for Constructing Well ER-EC-2A . . . . . . . . . . . . . . . . . . . 8-3
x
List of Tables
Number Title Page
1-1 Well ER-EC-2A Site Data Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
2-1 Abridged Drill Hole Statistics for Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
3-1 Sidewall Samples from Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3-2 Status of Rock Sample Analyses for Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3-3 Well ER-EC-2A Geophysical Log Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
7-1 Well ER-EC-2A Completion String Construction Summary . . . . . . . . . . . . . . . . . . . . 7-3
A-2 Casing Data for Well ER-EC-2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2-1
A-3-1 Well ER-EC-2A Drilling Fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3-1
A-3-2 Well ER-EC-2A Cement Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3-1
D-1 Well ER-EC-2A Geophysical Logs Presented . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1
xi
List of Acronyms and Abbreviations
BN Bechtel Nevada
C centigrade
cm centimeter(s)
DOE U.S. Department of Energy
DOE/NV U.S. Department of Energy, Nevada Operations Office
DRI Desert Research Institute
E east
EC Electrical Conductivity
F Fahrenheit
FMP Fluid Management Plan
ft foot (feet)
gal gallon(s)
gpm gallons per minute
in. inch(es)
IT IT Corporation
km kilometer(s)
lpm liters per minute
LANL Los Alamos National Laboratory
LiBr lithium bromide
m meter(s)
Ma million years ago
mi mile(s)
N north
NAD North American Datum
NNSA/NV U.S. Department of Energy, National Nuclear Security AdministrationNevada Operations Office
NTS Nevada Test Site
PM-OV Pahute Mesa - Oasis Valley
TD total depth
TFM Thermal Flow Meter
TMCC Timber Mountain caldera complex
TWG Technical Working Group
UGTA Underground Test Area
UDI United Drilling, Inc.
USGS United States Geological Survey
xii
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1-1
1.0 Introduction
1.1 Project Description
Well ER-EC-2A was drilled for the U.S. Department of Energy, National Nuclear Security
Administration Nevada Operations Office (NNSA/NV) in support of the Nevada Environmental
Restoration Project at the Nevada Test Site (NTS), Nye County, Nevada. Well ER-EC-2A is the
eighth in a series of wells to be drilled as part of the hydrogeologic investigation well program in
the Pahute Mesa - Oasis Valley (PM-OV) region of Nye County, Nevada. This program is part
of the NNSA/NV Environmental Restoration Division’s Underground Test Area (UGTA) project
at the NTS. The goals of the UGTA project include evaluating the nature and extent of
contamination in groundwater due to underground nuclear testing, and establishing a long-term
groundwater monitoring network. As part of the UGTA project, scientists are developing
computer models to predict groundwater flow and contaminant migration within and near the
NTS. To build and test these models, it is necessary to collect geologic, geophysical, and
hydrologic data from new and existing wells to define groundwater migration pathways,
migration rates, and quality.
The goal of the PM-OV program is to collect subsurface geologic and hydrologic data in a large,
poorly characterized area down-gradient from Pahute Mesa where underground nuclear tests
were conducted, and up-gradient from groundwater discharge and withdrawal sites in Oasis
Valley northeast of Beatty, Nevada (Figure 1-1). Data from these wells will allow for more
accurate modeling of groundwater flow and radionuclide migration in the region. Some of the
wells may also function as long-term monitoring wells.
Well ER-EC-2A is located within the Nellis Air Force Range complex, approximately
10 kilometers (km) (6 miles [mi]) southwest of the Area 20 underground nuclear test area
(Figure 1-1). The elevation of the dirt-fill drill pad at the wellhead is 1,494.1 meters (m)
(4,901.9 feet [ft]) above mean sea level. The Nevada State (central zone) plane coordinates
(North American Datum [NAD] 1983) at the wellhead are North (N) 6,265,715.6 and
East (E) 508,740.7 m (N 20,556,768.7 and E 1,669,093.5 ft). Additional site data are listed in
Table 1-1.
IT Corporation (IT) was the principal environmental contractor for the project, and IT personnel
collected geologic and hydrologic data during drilling. The drilling company was United
1-2
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NellisAir Force
Range
10,000 Meter UTM Tics Based on NAD83
Bureau ofLand
Management
NevadaTestSite
ThirstyMountain
ER-EC-2A
ER-EC-10
ER-EC-6
ER-EC-1
ER-18-2ER-EC-5
ER-EC-4
ER-EC-8
ER-EC-7
ER-EC-9
ER-EC-3
ER-OV-7
ER-OV-8
Area 19
Area 20
Area 18
Area 29
Area 30
Area 25
Area 17
Area 12
Area 16
Shoshone Mountain
Pahute Mesa
Ka
wic
h C
an
yo
n
TimberMountain
Oas
is V
alle
y
BeattyWash
BlackMountain
Elea
na
Ran
ge
BuckboardMesa
Redrock Valley
Fo
rty
mil
e C
an
yo
n
Rainier MesaBig Burn Valley
Yu
cca
Mtn
.
Th
irst
y C
an
yon
95
374 Beatty
116°40'0"W
116°40'0"W
116°30'0"W
116°30'0"W
37
°0
'0"N
37
°0
'0"N
37
°1
0'0
"N
37
°1
0'0
"N
37
°2
0'0
"N
37
°2
0'0
"N
520000
520000
530000
530000
540000
540000
550000
550000
40
80
00
0
40
80
00
0
40
90
00
0
40
90
00
0
41
00
00
0
41
00
00
0
41
10
00
0
41
10
00
0
41
20
00
0
41
20
00
0
41
30
00
0
41
30
00
0
PM-OV Well
Proposed PM-OV Well
Well Access Road
Proposed Well Access Road
Primary NTS Road
Highways (U.S. and State)
Nellis Air Force Range
Nevada Test Site
0 1 2 3 4 5
Miles
10,000 Meter UTM Tics Based on NAD83
10 Minute Latitude / Longitude Graticule
Figure 1-1Reference Map Showing Location of Well ER-EC-2a
(Proposed wells not drilled at time Well ER-EC-2a was drilled.)
1-3
NTS/GIS: jrc erec2a.mxd
31-OCT-2000
1-4
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1-5
Table 1-1Well ER-EC-2A Site Data Summary
Well Designation ER-EC-2A
Site Coordinates a
Nevada State Plane (ce ntral zone) (NAD 83):
N 6,265 ,715.6 m (N 20,55 6,768.7 ft)
E 508,7 40.7 m (E 1,669,09 3.5 ft)
Nevada State Plane (ce ntral zone) (NAD 27):
N 871 ,767.2 ft
E 528,9 37.9 ft
Universal Transverse Mercator (Zone 11)(N AD 83):
N 4,111,038.2 m
E 538,340.5 m
Surface Elevation b 1,494.1 m (4,901.9 ft)
Drilled Depth 1,516.1 m (4,974 ft)
Fluid-Level Depth c
228.0 m (747.9 ft)
Fluid-Level Elevation 1,266.1 m (4,154.0 ft)
a Measurement made by BN Survey.
b Measurement made by BN Survey. Elevation at top of construction pad. 1929 North American
Vertical D atum.
c Measured by IT on April 14, 2000, approximately two months after completion string was installed.
Drilling, Incorporated (UDI), a subcontractor to Bechtel Nevada (BN). Site supervision,
engineering, construction, inspection, and geologic support were provided by BN. The roles and
responsibilities of these and other contractors involved in the project are described in Contract
Number DE-RP-08-95NV11808, and in BN Drilling Work Plan Number D-001-002.00
(BN, 2000). The UGTA Technical Working Group (TWG), a committee of scientists and
engineers comprising NNSA/NV, Lawrence Livermore National Laboratory, Los Alamos
National Laboratory (LANL), and contractor personnel, provided additional technical advice
during drilling, design, and construction of the well. See FY99 Western Pahute Mesa-Oasis
Valley Hydrogeologic Investigation Wells Drilling and Completion Criteria (IT, 1998) for
descriptions of the general plan and goals of the PM-OV project, as well as specific goals for
each planned well.
General guidelines for managing fluids used and generated during drilling, completion, and
testing of UGTA wells are provided in the UGTA Fluid Management Plan (FMP)
(U.S. Department of Energy, Nevada Operations Office [DOE/NV], 1996a), an attachment to the
1-6
UGTA Waste Management Plan (DOE/NV, 1996b). Estimates of production of fluid and drill
cuttings for the PM-OV holes are given in Appendix N of the drilling and completion criteria
document for the PM-OV project (IT, 1998), along with sampling requirements and contingency
plans for management of any hazardous waste produced. All activities were conducted in
accordance with the Nevada Environmental Restoration Project Health and Safety Plan
(DOE/NV, 1998), and the Site-Specific Health and Safety Plan for PM-OV Investigation Wells
(BN, 1999).
This report presents construction data and summarizes scientific data gathered during drilling and
installation of the completion string. Some of the information in this report is preliminary and
unprocessed, but is being released with the drilling and completion data for convenient reference.
A well data report prepared by IT (IT, 2000) contains additional information on fluid
management, waste management, and environmental compliance. Updated geologic information
(including any changes in the geologic interpretation) will be compiled in the documentation
package for the PM-OV hydrostratigraphic framework model to be prepared by BN.
Information on well development, aquifer testing, and groundwater analytical sampling will be
compiled and disseminated separately by IT.
1.2 Objectives
The primary purpose of constructing Well ER-EC-2A was to obtain information which will help
characterize the hydrogeology of this part of the PM-OV area. Well-specific scientific
objectives, as discussed in Appendix B of the drilling criteria document (IT, 1998), include the
following:
! Explore the possibility of a deep groundwater flow regime.
! Obtain hydraulic properties for the rocks that fill the Timber Mountain caldera complexto determine how these rocks affect local groundwater flow.
! Determine groundwater levels to define the local groundwater flow system gradient.
Some of these objectives will not be met until additional work is completed, including installing
a pump and conducting hydraulic testing, and analyzing geology and hydrology data from this
and other wells in the PM-OV area.
1-7
1.3 Project Summary
This section summarizes Well ER-EC-2A construction operations; the details are provided in
Sections 2.0 through 8.0 of this report.
The surface conductor hole was constructed by augering a 121.9-centimeter (cm) (48-inch [in.])
diameter hole to a depth of 20.1 m (66 ft) and installing a string of 30-in. casing. Drilling of the
main hole with a 17½-in. rotary bit, using an air-water-foam fluid (with a polymer additive as
required) in conventional circulation, began on January 22, 2000. A suitable depth to set the
surface casing was reached at 418.2 m (1,372 ft). At this point, drilling was suspended for
geophysical logging, and then the 13d-in. surface casing string was landed at 412.9 m
(1,354.6 ft) on January 28, 2000, approximately 184.7 m (606 ft) below the static water level.
Drilling continued with a 12¼-in. bit to a total depth (TD) of 1,516.1 m (4,974 ft), which was
reached on February 6, 2000.
Water production was first noted at the depth of approximately 265.8 m (872 ft), and reached a
maximum of approximately 3,407 liters per minute (lpm) (900 gallons per minute [gpm]) near
the bottom of the hole. About two months after installation of the completion string, the fluid
level was tagged by IT at the depth of 228.0 m (747.9 ft). No radionuclides above background
levels were encountered during drilling of Well ER-EC-2A.
Composite drill cuttings were collected every 3.0 m (10 ft) from 36.6 m (120 ft) to TD, and
81 sidewall core samples were taken at various depths below 212.8 m (698.0 ft). Open-hole
geophysical logging of the well was conducted to help verify the geology and characterize the
hydrology of the rocks; some logs also aided in the construction of the well by indicating
borehole volume and condition, and cement location. The well penetrated lavas and tuffs of the
Volcanics of Fortymile Canyon and the Timber Mountain Group.
A single completion string was installed in Well ER-EC-2A on February 11, 2000. Stainless
steel, 5½-in. production casing was landed at 1,512.0 m (4,960.5 ft). The bull-nosed string has
three slotted intervals, at 1,367.7 to 1,498.3 m (4,487.2 to 4,915.8 ft), 937.8 to 1,081.6 m
(3,076.7 to 3,548.6 ft), and 520.3 to 664.1 m (1,707.1 to 2,178.8 ft). Internally epoxy-coated,
7e-in. carbon-steel casing extends from the top of the 5½-in. casing to the ground surface. The
completion string was gravel-packed across the slotted intervals and the remaining annular space
was filled with gravel, sand, and cement to the depth of 210.9 m (692 ft) on February 14, 2000.
1-8
No pump was installed at the time of completion, but will be inserted as needed for hydrologic
sampling and testing activities.
1.4 Project Manager
Inquiries concerning Well ER-EC-2A should be directed to the UGTA Project Manager at:
U.S. Department of EnergyNational Nuclear Security AdministrationNevada Operations OfficeEnvironmental Restoration DivisionPost Office Box 98518Las Vegas, Nevada 89193-8518
2-1
2.0 Drilling Summary
2.1 Introduction
This section contains detailed descriptions of the drilling process and fluid management issues.
The general drilling requirements for all PM-OV wells were provided in FY99 Western Pahute
Mesa-Oasis Valley Hydrogeologic Investigation Wells Drilling and Completion Criteria
(IT, 1998). Specific requirements for Well ER-EC-2A were outlined in Drilling Work Plan
Number D-001-002.00 (BN, 2000). Figure 2-1 shows the layout of the drill site. Figure 2-2 is a
chart of the drilling and completion history for Well ER-EC-2A. A summary of drilling statistics
for the well is given in Table 2-1. The following information was compiled primarily from BN
daily drilling reports.
2.2 Drilling History
Field operations at Well ER-EC-2A began when BN drillers using an auger rig drilled a
121.9-cm (48-in.) conductor hole in three passes to 20.1 m (66 ft). A string of 30-in. casing was
set at the depth of 19.8 m (65 ft). The bottom of the conductor casing was cemented inside to
19.2 m (63 ft), and the annulus was cemented from the bottom of the casing to ground level on
January 13, 2000.
The UDI crews rigged up the Wilson Mogul 42B rig on January 17 through 20, 2000, and tagged
cement at the depth of 19.2 m (63 ft). Drilling resumed through the cement with a center-punch
assembly consisting of a 17½-in. rotary bit mounted below a 26-in. hole opener on
January 21, 2000, using air, water, and foam (“air-foam”) in conventional circulation. When the
17½-in. bit reached a depth of 22.6 m (74 ft) and the 26-in. hole opener had cleared the bottom of
the 30-in. casing, the center-punch assembly was tripped out of the hole. The hole opener was
removed, a new 17½-in bit was tripped into the hole, and drilling resumed.
Drilling of the main hole with a 17½-in. rotary bit and air-foam began January 22, 2000.
Beginning at a depth of 38.4 m (126 ft), a polymer additive was added to the air-foam injection
mix. The first water production was noted by IT personnel at a depth of approximately 265.8 m
(872 ft).
As a precaution against sloughing of the upper section of unsaturated volcanic rocks, it was
decided to install surface casing when a competent formation for supporting the casing was
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2-7
Table 2-1Abridged Drill Hole Statistics for Well ER-EC-2A
LOCATION DATA:
Coordinates: Nevada State Plane (central zone): NAD 83: N 6,265,715.6 m E 508,740.7 m NAD 27: N 871,767.2 ft E 528,937.9 ft
Universal Transverse Mercator: NAD 83: N 4,111,038.2 m E 538,340.5 mSurface Elevation a: 1,494.1 m (4,901.9 ft)
DRILLING DATA:
Spud Date: 1/21/2000 (main hole drilling with Wilson Mogul 42B rig)Total Depth (TD): 1,516.1 m (4,974 ft)Date TD Reached: 2/06/2000Date Well Completed b: 2/14/2000Hole Diameter: 121.9 cm (48 in.) from surface to 20.1 m (66 ft.); 44.5 cm (17.5 in.) from 20.1 to
418.2 m (66 to1,372 ft); 31.1 cm ( 12.25 in.) from 418.2 m (1,372 ft) to TD of1,516.1 m (4,974 ft).
Drilling Techniques: Dry-hole auger from surface to 20.1 m (66 ft.); rotary drilling with 17½-in. bitusing air-foam in direct circulation from 20.1 to 38.4 m (66 to 126 ft); rotarydrilling with 17½-in. bit using air-foam and polymer in direct circulation from38.4 to 418.2 m (126 to 1,372 ft); rotary drilling with 12¼-in. bit and air-foam/polymer to TD of 1,516.1 m (4,974 ft).
CASING DATA: 30-in. conductor casing, surface to 19.8 m (65 ft); 13d-in. surface casing, surface to412.9 m (1,354.6 ft).
WELL COMPLETION DATA:The completion string consists of 7e-in. carbon-steel casing with an internal epoxy coating, connected to5½-in. stainless-steel casing via an internally coated carbon-steel cross-over sub. The carbon-steelcasing extends through the unsaturated zone approximately 188.7 m (619 ft) into the top of the saturatedzone. The 14.13-cm (5.563-in.) outside-diameter stainless-steel casing has a 12.82-cm (5.047-in.)inside diameter, is bull-nosed, and has three slotted intervals (listed below) that each consist ofconsecutive slotted joints. Detailed data for the completion intervals are provided in Section 7.0 of thisreport.
Total Depth: 1,512.0 m (4,960.5 ft)
Depth of Slotted Sections: 520.3 to 664.1 m 937.8 to 1,081.6 m 1,367.7 to 1,498.3 m(1,707.1 to 2,178.8 ft) (3,076.7 to 3,548.6 ft) (4,487.2 to 4,915.8 ft)
Depth of Sand Packs: 498.3 to 508.4 m 922.0 to 931.8 m 1,344.2 to 1,357.6 m(1,635 to 1,668 ft) (3,025 to 3,057 ft) (4,410 to 4,454 ft)
Depth of Gravel Packs: 508.4 to 681.5 m 931.8 to 1,098.2 m 1,357.6 to 1,514.6 m(1,668 to 2,236 ft) (3,057 to 3,603 ft) (4,454 to 4,969 ft)
Depth of Pump: Not installed at time of completion.
Water Depth c: 228.0 m (747.9 ft)
DRILLING CONTRACTOR: United Drilling, Inc.GEOPHYSICAL LOGS BY: Schlumberger, Colog, Inc. Desert Research Institute, Gyrodata, Inc.
SURVEYING CONTRACTOR: Bechtel Nevada
a Elevation of ground level at wellhead. 1929 North American Vertical Datum. b Date completion string was cemented. Pump will be installed at a later date.c Measured by IT on April 14, 2000, approximately two months after completion string was installed.
2-8
reached. The decision was made to stop and set casing on January 26, 2000, at a depth of
418.2 m (1,372 ft), where water production had reached an estimated rate of 379 lpm (100 gpm).
The drillers circulated fluid to clean and condition the hole, pulled the drill string off the bottom,
and waited about 20 minutes before tagging bottom again. No fill was found, and the drillers
tripped the drill string out of the hole. Drilling activity was suspended for 14 hours during
geophysical logging, prior to installation of the surface casing.
A casing subcontractor landed 13d-in. casing that has ribbon stabilizers (centralizers) installed
above the guide shoe, at the middle and at the top of the first joint, and at the top of the second
joint. A stab-in float collar was installed between the first and second joints. Two metal-petal
cement baskets are located at 20.4 m (67 ft) below ground level. The casing was landed at a
depth of 412.9 m (1,354.6 ft) on January 28, 2000, above about 4 m (13 ft) of fill that had
accumulated in the bottom of the surface hole during geophysical logging. After the stab-in sub
was seated in the float shoe, the seal was checked by pumping air down the drill pipe. Pre-flush
clear water was pumped down the casing and the annulus prior to cementing. Type II cement
was pumped inside the casing through the stab-in sub, followed by water to displace the cement
into the annulus. The top of cement in the annulus was later determined by geophysical logs to
be at the depth of approximately 228.6 m (750 ft). After the drill pipe was tripped out of the
hole, a mix of gravel and sand was dropped on the cement baskets, and the remaining annulus
was cemented to ground level with Type II cement. Cementing of the surface casing was
completed on January 28, 2000. The top of cement inside the casing was tagged at 398.7 m
(1,308 ft) when the bottom-hole assembly was tripped back into the hole.
After drilling about 7 m (23 ft) of cement, the drillers stopped to pull the drill string out of the
hole to check the pipe tally. The tally was deemed correct, so the drillers tripped the drill string
back into the hole and resumed drilling out cement. Drilling was stopped on January 29, 2000,
just above the cement shoe, at the depth of 412.7 m (1,354 ft), because it was noted that the fluid
level in Sump #1 was approaching the overflow pipe. Discharge to the ground surface would not
be permitted if the sump fluid were found to contain contaminants. The results of the analysis of
a sample taken from the sump at the end of surface-hole drilling on January 25, 2000, had not yet
been received, so drilling was stopped until the analysis was completed. The bit was pulled up
into the casing, and drilling operations were put on standby for 10 hours. Drilling was allowed to
resume at 1400 hours on January 29, 2000, after receipt of the analysis, which indicated no
contaminant present above critical levels.
2-9
When drilling resumed, the discharge valve on the overflow pipe in Sump #1 was opened, and
drilling of cement continued to 414.2 m (1,359 ft). Fill was encountered at 414.2 to 418.2 m
(1,359 to 1,372 ft), then drilling continued into the formation, using air-foam with a polymer
additive. On February 2, 2000, at a depth of 1,100.6 m (3,611 ft), the drill string was tripped out
of the hole for a bit change. The bit was replaced with a new 12¼-in. chisel-tooth bit, and
drilling continued uninterrupted to the TD of 1,516.1 m (4,974 ft), reached on February 6, 2000.
The amounts of polymer and foaming agent in the drilling fluid, and the fluid injection rate, were
adjusted as necessary during drilling to maintain superior circulation and penetration rate, and to
minimize borehole sloughing. However, fill (due to sloughing of the borehole wall) was
encountered during drilling of some portions of Well ER-EC-2A, though it did not cause
significant delays in the drilling. Between the depths of 29.3 and 85.0 m (96 and 279 ft), 0.6 to
3.0 m (2 to 10 ft) of fill was encountered on most connections. Below this zone, fill of 1.5 m
(5 ft) or less was encountered on a few connections, and a significant amount of sloughed
material accumulated during geophysical logging. At the time the completion string was
installed, approximately 1.5 m (5 ft) of fill remained in the bottom of the hole.
The TD was reached approximately 7.9 m (26 ft) short of the planned depth of 1,066.8 m
(5,000 ft), after the rate of penetration became slow. Geologists and the TWG determined that no
further valuable stratigraphic data would be gained by drilling the last 7.9 m (26 ft). Immediately
after reaching TD, the drillers circulated fluid to condition the hole before the second phase of
geophysical logging, which took place on February 7 - 9, 2000. Installation of the completion
string began on February 10, 2000. Demobilization from the Well ER-EC-2A site began after
gravel-packing and cementing were completed on February 14, 2000.
The directional survey run in the well on August 10, 2000, indicates that at the lowest surveyed
depth of 1,499.6 m (4,920 ft) the hole had drifted 27.7 m (90.9 ft) to the east of the collar
location, and that the hole is relatively straight (no “dog legs”).
A graphical depiction of drilling parameters including penetration rate, revolutions per minute,
pump pressure, and weight on the bit is presented in Appendix A-1. See Appendix A-2 for a
listing of casing materials. Drilling fluids and cements used in Well ER-EC-2A are listed in
Appendix A-3.
2-10
2.3 Drilling Problems
No significant drilling problems were encountered at Well ER-EC-2A. Fill of generally less than
3.0 m (10 ft) was encountered periodically throughout drilling, but did not result in significant
drilling delays. The Drilling Work Plan (BN, 2000) contained provisions for setting intermediate
casing in the event that sloughing hole conditions or high water production caused drilling
difficulties; however, neither was a problem and intermediate casing was not required in
Well ER-EC-2A. The only significant delay encountered was the result of fluid-management
issues, discussed in Subsection 2.4. Drilling was stopped 7.9 m (26 ft) short of the planned TD
of 1,524.0 m (5,000 ft) due to a slowing in the rate of penetration. This is not thought to have
caused the loss of any significant data.
2.4 Fluid Management
Drilling effluent was monitored in accordance with the methods prescribed in the UGTA FMP
(DOE/NV, 1996a). The air-foam/polymer drill fluid was circulated down the inside of the drill
string and back up the hole through the annulus (conventional or direct circulation) and then
discharged into a sump. Water used to prepare drilling fluids came from the Coffer Dune Well,
located on the Coffer Ranch. Lithium bromide (LiBr) was added to the drill fluid as a tracer to
provide a means of estimating groundwater production. The rate of water inflow was estimated
from the dilution of the tracer in the drill fluid returns.
To manage the anticipated water production, two sumps were constructed prior to drilling
(Figure 2-1). No contaminants were expected during drilling at this site, so neither sump was
lined prior to drilling. Samples of drilling effluent were tested on-site hourly for the presence of
tritium, and every eight hours for lead. The on-site monitoring results indicate that tritium
remained at background levels, and lead was undetectable (less than 50 parts per billion) during
the entire drilling operation.
Before fluids are discharged from a sump through the overflow pipe, the FMP requires that a
sample be collected from the sump and analyzed off-site to verify on-site monitoring data and
demonstrate compliance with the FMP. Duplicate samples were collected from Sump #1 on
January 25, 2000, after drilling of the surface hole. While the sample was being analyzed,
geophysical logging of the surface hole was conducted, the surface casing was installed, and
drilling continued through the cement inside the casing, before being halted to wait for the
analysis results. The analytical results showed the sump fluids were within the parameters of the
2-11
FMP criteria. Samples from both sumps were also collected and analyzed at the end of drilling
operations. Water-quality data for all four sump samples are provided in Appendix B.
The results of analyses of samples of drilling fluid collected at Well ER-EC-2A during drilling
operations indicate that all fluid quality objectives were met, as shown on the fluid management
reporting form dated July 28, 2000 (Appendix B). The form lists volumes of solids (drill
cuttings) and fluids produced during well-construction operations, Stages I and II (i.e., vadose-
and saturated-zone drilling only; well development and aquifer testing will be conducted at a
later date). The volume of solids produced was calculated using the diameter of the borehole
(from caliper logs) and the depth drilled, and includes added volume attributed to a rock bulking
factor. The volumes of fluids listed on the report are estimates of total fluid production, and do
not account for any infiltration or evaporation of fluids from the sumps.
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3-1
3.0 Geologic Data Collection
3.1 Introduction
This section describes the sources of geologic data obtained from Well ER-EC-2A and the
methods of data collection. Improving the understanding of the subsurface structure,
stratigraphy, and hydrogeology in the area southwest of Pahute Mesa was among the primary
objectives of Well ER-EC-2A, so the proper collection of geologic and hydrogeologic data from
Well ER-EC-2A was considered fundamental to successful completion of the project.
Geologic data collected at Well ER-EC-2A consist of drill cuttings, sidewall core samples, and
geophysical logs. Data collection, sampling, transfer, and documentation activities were
performed in accordance with applicable contractor procedures.
3.2 Collection of Drill Cuttings
Composite drill cuttings were collected from Well ER-EC-2A at 3.05-m (10-ft) intervals as
drilling progressed from the depth of 36.6 m (60 ft) to the TD of the well at 1,516.1 m (4,974 ft).
Triplicate samples were collected from 490 intervals (samples were not collected from two
intervals), and in addition, the IT field representative collected two sets of reference samples
from each of the cuttings intervals. One set was examined at the drill site for use in preparing
field lithologic descriptions, and remains in the custody of IT. The other set was sent to
R. G. Warren (LANL) where it remains. All other samples (i.e., three sets of 490 samples) are
stored under controlled conditions at the U. S. Geological Survey (USGS) Geologic Data Center
and Core Library in Mercury, Nevada. One of these sample sets was sealed with custody tape at
the rig site and remains sealed as an archive sample; one set was left unsealed in the original
sample containers; and the third set was washed and stored in accordance with standard USGS
Core Library procedures.
3.3 Sidewall Core Samples
Sidewall core samples were collected by Schlumberger from Well ER-EC-2A to verify the
stratigraphy and lithology at selected locations. Sample locations were selected by the IT Field
Representative on the basis of field lithologic logs (with consideration of borehole conditions
determined from caliper logs). A percussion gun tool was used to collect 17 sidewall cores in the
upper 413.3 m (1,356 ft) of the borehole on January 27, 2000, prior to installing surface casing.
Prior to installation of the completion string, Schlumberger collected 39 percussion and 25 rotary
3-2
sidewall cores from the lower part of the borehole. Table 3-1 1ists the recovery and stratigraphic
assignment for each sample.
3.4 Sample Analysis
Thirty samples of drill cuttings from various depths in Well ER-EC-2A were submitted to the
LANL Earth and Environmental Sciences Division - Geology and Geochemistry laboratories for
petrographic, mineralogic, and chemical analyses to aid in stratigraphic identification and for
characterization of mineral alteration. All of the planned analyses have been completed, as
shown on Table 3-2.
3.5 Geophysical Data
Geophysical logs were run in the borehole to further characterize the lithology, structure, and
water content of the rocks encountered. In addition, logs were run to evaluate borehole
conditions, to determine the fluid levels during the course of drilling, and to monitor completion
progress. Geophysical logging was conducted during three stages of drilling and completion:
prior to setting surface casing, prior to installing the completion well casing, and during well
installation (annulus investigation log). Some logs were run in both the saturated and
unsaturated zones of the borehole, while others (e.g., thermal flow log, chemistry log, ultrasonic
borehole imager log, etc.) were run only in the saturated interval. A complete listing of the logs,
dates run, depths, and service companies is provided in Table 3-3. The logs are available from
BN in Mercury, Nevada, and copies are on file at the IT office in Las Vegas, Nevada.
Preliminary geophysical data from the logs are reproduced in Appendix D.
The overall quality of the geophysical data collected was good. However, high flow velocities in
the borehole exceeded the range for the thermal flow tool run by Desert Research Institute (DRI)
personnel, so DRI ran their “spinner” tool, a full bore flow meter, to determine flow gradients.
This tool did not arrive on-site calibrated for a 12¼-in. diameter borehole, so additional time was
required for calibration in the field. Because the tool was used under conditions for which it was
not specifically designed, the resultant data set should be carefully evaluated.
3-3
Table 3-1Sidewall Samples from Well ER-EC-2A
(Page 1 of 2)
Core Depthmeters (feet)
ToolUsed a
LengthRecoveredb
cm (in.)
StratigraphicUnit c
212.8 (698) SWC 1.25
Tfbw
227.4 (746) SWC 1.25
233.8 (767) SWC 0.25
268.2 (880) SWC 0.25
335.9 (1,102) SWC 0.5
359.7 (1,180) SWC 1.5
374.0 (1,227) SWC 1.25
381.3 (1,251) SWC 1.25
385.0 (1,263) SWC 1.25
387.1 (1,270) SWC 1.5
390.1 (1,280) SWC 0.25
393.2 (1,290) SWC 0.25
399.9 (1,312) SWC 0.25
405.4 (1,330) SWC 0.5
407.8 (1,338) SWC 1.0
410.9 (1,348) SWC 0.75
413.3 (1,356) SWC 1.25
448.1 (1,470) SWC 1.5
460.9(1,512) SWC 1.0
469.1 (1,539) SWC 1.25
495.9 (1,627) SWC 0.5
509.6 (1,672) SWC 0.5
Core Depthmeters (feet) Tool
Used aLength
Recoveredb
cm (in.)
StratigraphicUnit c
556.3 (1,825) SWC 1.0
Tfbw
589.8 (1,935) SWC 0.25
615.4 (2,019) SWC 1.5
625.4 (2,052) SWC 1.5
640.4 (2,101) SWC 1.5
648.0 (2,126) SWC 1.5
656.5 (2,154) SWC 1.75
662.9 (2,175) SWC 2.0
676.7 (2,220) SWC 1.75
Tfb
687.0 (2,254) SWC 1.75
700.7 (2,299) SWC 1.75
711.7 (2,335) SWC 1.75
738.8 (2,424) SWC 1.5
778.8 (2,555) SWC 1.75
790.0 (2,592) SWC 0.5
808.0 (2,651) SWC 1.75
815.0 (2,674) SWC 1.75
862.6 (2,830) SWC 0.25
874.8 (2,870) SWC 1.5
883.9 (2,900) SWC 1.5
887.9 (2,913) SWC 1.5
900.4 (2,954) SWC 1.0
Table 3-1Sidewall Samples from Well ER-EC-2A
(Page 2 of 2)
3-4
Core Depthmeters (feet)
ToolUsed a
LengthRecoveredb
cm (in.)
StratigraphicUnit c
907.4 (2,977) SWC 2.0
Tfb914.4 (3,000) SWC 1.75
929.6 (3,050) SWC 1.5
941.8 (3,090) SWC 1.0
Tf
950.4 (3,118) SWC 1.5
955.5 (3,135) MSCT .025
957.1 (3,140) MSCT 0.25
959.5 (3,148) MSCT 0.25
964.7 (3,165) MSCT 0.5
Tm
966.2 (3,170) MSCT 1.25
986.0 (3,235) MSCT 1.25
991.5 (3,253) SWC 0.25
997.6 (3,273) SWC 0.75
1,006.1 (3,301) SWC 1.0
1,012.5 (3,322) SWC 1.0
1,018.3 (3,341) SWC 1.0
1,023.8 (3,359) SWC 0.75
1,026.6 (3,368) MSCT 1.25
1,027.2 (3,370) SWC 0.5
Core Depthmeters (feet)
ToolUsed a
LengthRecoveredb
cm (in.)
StratigraphicUnit c
1,086.9 (3,566) MSCT 0.5
Tm
1,136.9 (3,730) MSCT 1.5
1,160.1 (3,806) MSCT 1.25
1,210.1 (3,970) MSCT 1.25
1,266.4 (4,155) MSCT 0.5
1,285.3 (4,217) MSCT 1.0
1,309.4 (4,296) MSCT 0.5
1,316.7 (4,320) MSCT 0.75
1,345.1 (4,413) MSCT 0.25
1,383.5 (4,539) MSCT 1.25
1,385.9 (4,547) MSCT 1.25
1,393.2 (4,571) MSCT 1.0
1,403.0 (4,603) MSCT 0.75
1,405.1 (4,610) MSCT 1.5
1,417.6 (4,651) MSCT 1.25
1,439.3 (4,722) MSCT 1.0
1,466.7 (4,812) MSCT 1.25Tmar
1,508.2 (4,948) MSCT 1.25
a SWC = Percussion sidewall gun operated by Schlumberger; MSCT = rotary mechanical sidewall coring tool operated by Schlumberger.b Estimatedc Preliminary assignments: Tfbw = rhyolite of Beatty Wash; Tfb = Beatty Wash Formation (undivided); Tf = Volcanics of Fortymile Canyon (undivided);
Tm = Timber Mountain Group (undivided); Tmar = mafic-rich Ammonia Tanks Tuff. See Appendix C for more information about the stratigraphy andlithology of Well ER-EC-2A.
3-5
Table 3-2Status of Rock Sample Analyses for Well ER-EC-2A
Depth a
meters (feet)
Analyses Performed b
Petrogra phic Mine ralog ic Chemical
PS MP XRD XRF Fe+2
/Fe+3
27.4 (90) QL N/P C C C
207.3 (680) QL N/P C C C
228.6 (750) QL N/P C C C
307.8 (1,010) QL N/P C C C
384.0 (1,260) QL N/P C C C
411.5 (1,350) QL N/P C C C
457.2 (1,500) QL N/P C C C
518.2 (1,700) QL N/P C C C
597.4 (1,960) QL N/P C C C
667.5 (2,190) QL N/P C C C
725.4 (2,380) QL N/P C C C
792.5 (2,600) QL N/P C C C
847.3 (2,780) QL C C C C
902.2 (2,960) QL N/P C C C
932.7 (3,060) QL N/P C C C
954.0 (3,130) QL N/P C C C
960.1 (3,150) QL N/P C C C
966.2 (3,170) QL N/P C C C
978.4 (3,210) QL N/P C C C
1,008.9 (3,310) QL N/P C C C
1,069.8 (3,510) QL N/P C C C
1,133.9 (3,720) QL N/P C C C
1,173.5 (3,850) QL N/P C C C
1,243.6 (4,080) QL N/P C C C
1,304.5 (4,280) QL N/P C C C
1,356.4 (4,450) QL N/P C C C
1,405.1 (4,610) QL N/P C C C
1,429.5 (4,690) QL N/P C C C
1,472.2 (4,830) QL N/P C C C
1,516.1 (4,974) QL C C C C
a Depth represents base of 3.0-m (10-ft) sample interval for drill cuttings. All samples are drill cuttings thatrepresent the lithologic character of the interval.
b Status of analyses at the time of this writing: C = analysis complete; QL = qualitative analysis complete; N/P = analysis not planned. Analysis type: PS = polished thin section; MP = electron microprobe; XRD = x-raydiffraction; XRF = x-ray fluorescence; Fe
+2/Fe+3 = wet chemical analysis for iron.
3-6
Table 3-3Well ER-EC-2A Geophysical Log Summary
(Page 1 of 2)
Geophysical Log Type a Log PurposeLoggingService
DateLogged
Run Number
Bottom ofLogged
Interval b
meters (feet)
Top of LoggedInterval b
meters (feet)
* Natural Gamma Ray Spectroscopy Stratigraphic correlation,mineralogy, natural and man-maderadiation
Schlumberger01/27/2000
02/08/2000
SGR-1
SGR-2
414.8 (1,361)
1,504.5 (4,936)
0.0 (0)
371.9 (1,220)
* Four Arm Caliper/Gamma Ray Borehole conditions, cementvolume calculation /stratigraphic correlation
Schlumberger01/27/2000
02/07/2000
CA4-1/ SGR-1
CA4-2/ GR-2
414.8 (1,361)
1,515.8 (4,973)
19.8 (65)
393.2 (1,290)
* Array Induction Log/Caliper/Gamma Ray/SP
Lithologic determination /borehole conditions /stratigraphic correlation
Schlumberger 01/27/2000 IND-1/ GR-1/ CAL-1/SP-1 412.7 (1,354) 19.8 (65)
* Epithermal Neutron/Density/Gamma Ray/ Caliper
Total water content / rock porosity/ stratigraphic correlation/boreholeconditions Schlumberger
01/27/2000
02/08/2000
ENP-1/CDL-1/GR-1/CAL-1
ENP-2/CDL-2/GR-3/CAL-2
409.7 (1,344)
1,510.3 (4,955)
19.8 (65)
396.2 (1,300)
* Dual Laterolog/ *SpontaneousPotential/Gamma Ray
Saturated zone: water saturation /stratigraphic correlation Schlumberger 02/08/2000 DLL-1/ SP-3 /GR-3 1,510.3 (4,955) 396.2 (1,300)
Gamma Ray/Digital Array SonicA. Wave-form and variable densitypresentations* B. Sonic porosity and travel time(STC) computations
Saturated zone:A. Porosity, lithologic determination
B. Fracture identificationSchlumberger 02/08/2000 AC-1/ GR-4 1,511.8 (4,960) 335.3 (1,100)
Ultrasonic Borehole Imager Saturated zone: lithologiccharacterization, fracture and voidanalysis.
Schlumberger 02/08/2000 BHTV-1 1,513.0 (4,964) 396.2 (1,300)
Temperature/Gamma Ray Saturated zone: groundwatertemperature / stratigraphiccorrelation
Schlumberger 02/07/2000 TL-1/GR-2 1,505.1 (4,938) 140.2 (460)
Chronological SidewallCores/Spontaneous Potential
Geologic samplesSchlumberger
01/27/2000
02/08/2000
SGUN-1/SP-2
SGUN-2/SP-5
412.1 (1,352)
1,027.2 (3,370)
32.3 (106)
448.1 (1,470)
Mechanical Sidewall CoringTool/Gamma Ray
Geologic samples Schlumberger 02/08/2000 MSCT-1/GR-5 1,508.2 (4,948) 955.5 (3,135)
Ambient Full-Bore Flowmeter /Temperature Log
Rate and direction of groundwaterflow in borehole / groundwatertemperature
DesertResearchInstitute
02/09/2000 SPINR-1/TL-2 1,513.3 (4,965) 369.2 (1,300)
Table 3-3Well ER-EC-2A Geophysical Log Summary
(Page 2 of 2)
3-7
Geophysical Log Type a Log PurposeLoggingService
DateLogged
Run Number
Bottom ofLogged
Interval b
meters (feet)
Top of LoggedInterval b
meters (feet)
* Thermal Flow Log Rate and direction of groundwaterflow in borehole
DesertResearchInstitute
02/09/2000 1 1,082.0 (3,550) 502.9 (1,650)
* Chemistry/Temperature Log Groundwater chemistry andtemperature, formationtransmissivity
DesertResearchInstitute
02/09/2000 1 1,515.8 (4,973) 257.3 (844)
Nuclear Annulus Investigation Log Well construction monitoring Colog 02/11-14/2000 AIN-1 1,511.8 (4,960) 178.6 (586)
Gyroscopic Directional Survey Borehole deviation Gyrodata 08/10/2000 1 1,499.6 (4,920) 0
a Logs presented in geophysical log summary, Appendix D, are indicated by *.
b Depth below ground surface.
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4-1
4.0 Geology and Hydrogeology
4.1 Introduction
This section summarizes the geology and hydrogeology of Well ER-EC-2A. Bechtel Nevada
geologists prepared the detailed lithologic descriptions presented in Appendix C, incorporating
information from field lithologic descriptions by IT well-site geologists and geophysical log data.
Stratigraphic assignments and identification of alteration mineralogy presented here are based
primarily on mineralogic and chemical data and interpretations provided by R. G. Warren of
LANL (Warren, 2000). See Table 3-2 for a list of laboratory analyses conducted at LANL on
samples from Well ER-EC-2A.
4.2 Geology
This section is subdivided into discussions of the stratigraphic section and structural features
interpreted from Well ER-EC-2A data, followed by a discussion of alteration noted in samples
from the well.
4.2.1 Stratigraphy and Structure
Well ER-EC-2A is located within the northwestern moat area of the Timber Mountain caldera
complex (TMCC) (Figure 4-1), which consists of several “nested” calderas. Analysis of the data
from Well ER-EC-2A and regional geologic and geophysical data suggest that the well is located
within both the Rainier Mesa and Ammonia Tanks calderas, two of the calderas in the TMCC.
The formation of these calderas is the result of the eruption of the Rainier Mesa Tuff (erupted
11.6 million years ago [Ma] [Sawyer, et al., 1994]) and the Ammonia Tanks Tuff (erupted
11.45 Ma [Sawyer, et al., 1994]); both tuffs are considered stratigraphically to be part of the
Timber Mountain Group. Following the collapse of the Ammonia Tanks caldera, resurgence of a
central dome created the present topographic expression of the TMCC, including Timber
Mountain and the surrounding "moat" (Figure 4-1). Younger volcanic rocks partially fill the
moat, and bury most of the Timber Mountain Group rocks within the moat. Moat-filling units
exposed at the surface near Well ER-EC-2A (Figure 4-2) include tuff and lava of the Volcanics
of Fortymile Canyon (erupted from various vents near the TMCC shortly after resurgence of the
central dome of the Ammonia Tanks caldera), ash-flow tuff of the Thirsty Canyon Group
(erupted from the Black Mountain caldera located north of Well ER-EC-2A; see Figure 4-1), and
younger colluvium and alluvium.
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NellisAir Force
Range
10,000 Meter UTM Tics Based on NAD83
Bureau ofLand
Management
NevadaTestSite
Black Mountain
Caldera
Tim
ber Mountain Moat
95
374
ER-EC-2A
ER-EC-10
ER-EC-6ER-EC-1
ER-18-2ER-EC-5
ER-EC-4
ER-EC-8
ER-EC-7
ER-EC-9
ER-EC-3
ER-OV-7
ER-OV-8
Area 19
Area 20
Area 18
Area 29
Area 30
Area 25
Area 17
Area 12
Area 16
Shoshone Mountain
Pahute Mesa
Ka
wic
h C
an
yo
n
TimberMountain
Oasi
s V
alley
BeattyWash
BlackMountain
Ele
ana
Ran
ge
BuckboardMesa
Redrock Valley
Fo
rty
mil
e C
an
yo
n
Rainier Mesa
Big Burn Valley
Yu
cca
Mtn
.
Th
irst
y C
an
yo
n
Silent Canyon
Caldera Complex
Claim Canyon
Caldera Complex
Timber Mountain
Caldera Complex
Beatty
116°40'0"W
116°40'0"W
116°30'0"W
116°30'0"W
37
°0
'0"N
37
°0
'0"N
37
°1
0'0
"N
37
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"N
37
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"N
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"N
520000
520000
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550000
40
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Caldera Boundary
WPM-OV Well
Proposed WPM-OV Well
Well Access Road
Proposed Well Access Road
Primary NTS Road
Highways (U.S. and State)
Nellis Air Force Range
Nevada Test Site
0 1 2 3 4 5
Miles
10,000 Meter UTM Tics Based on NAD83
10 Minute Latitude / Longitude Graticule
Figure 4-1Map of Pahute Mesa - Oasis Valley Area Showing
Theorized Locations of Caldera Boundaries (after Wahl et al., 1997)(Proposed wells not drilled at time Well ER-EC-2A was drilled.)
4-3
NT
S/G
IS:
jrc
ere
c2
a_
c.m
xd
05
-M
AY
-20
01
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ER-EC-2AER-EC-2AABAB
A'B'A'B'
Ttp
Ttp
Ttp
Ttp
Ttp
Ttp
Ttp
Ttp
Ttp
Ttp
Ttp
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Ttt
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Ttt
Ttp
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Qay
Ttp
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Qam
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Qay
Ttp
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Ttp
Ttg
Ttt
Tft
Tyb
Ttc
Qay
Tft
Tyb
Ttt
Ttc
Tma
Ttt
TfdTft
Ttp
Tgy
Qay
Ttp
QTc
Ttp
Tfb
Ttp
QTa
QTc Qam
Qay
QTcQTc
Ttt
Tfb
Tfb
Ttp
Ttg
Qay
Qam
Qay
Ttp
Qam
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Ttp
QTc
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QTc
Typ
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Ttt
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QTc
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Qay
Tfb
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Tft
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QTc
Ttp
Qay
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Qay
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QTc
QTa
Qay
Ttg
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QTc
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QTc
Ttt
Qam
Ttg
QTc
Tfb
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QTc
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Tfd
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QTc
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Ttg
Qam
QTc
Ttg
QTc
QTc
Ttc
116°37'30"W
116°37'30"W
116°35'0"W
116°35'0"W
116°32'30"W
116°32'30"W
37
°7
'30"N
37
°7
'30"N
37
°1
0'0
"N
37
°1
0'0
"N
534000
534000
536000
536000
538000
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540000
540000
542000
542000
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Figure 4-2Surface Geologic Map of the Well ER-EC-2A Site
4-5
NTSGIS:bma_erec2ageol.mxd
04-MAY-2001
EXPLANATONGeologic Units
QTa - Surficial deposits, undivided
QTc - Colluvium (Quaternary and Tertiary)
Qam - Middle alluvium (middle Pleistocene)
Qay - Young alluvium (Holocene & late Pleistocene)
Tfb - Beatty Wash Formation (undivided)
Tfd - Lavas of Dome Mountain
Tft - Post-Timber Mountain basaltic rocks
Tgy - Younger sedimentary deposits
Tma - Ammonia Tanks Tuff
Ttc - Comendite of Ribbon Cliff
Ttg - Gold Flat Tuff
Ttp - Pahute Mesa and Rocket Wash Tuffs
Ttt - Trail Ridge Tuff
Tyb - Thirsty Canyon and younger basalts
Typ - Pliocene and youngest Miocene basalt
Well access road
Normal fault; ball and bar on
downthrown side
Cross-section line
Geology adapted from Wahl et al., 19972,000 Meter UTM Tics Based on NAD832.5 Minute Latitude/Longitude Graticule
2,000 0 2,000 4,0001,000
Feet
500 0 500 1,000250
Meters
4-6
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4-7
The stratigraphy and lithology of Well ER-EC-2A are illustrated in Figure 4-3. Well ER-EC-2A
penetrated more than 914.4 m (3,000 ft) of mainly lava and tuff of the Volcanics of Fortymile
Canyon. Below the Volcanics of Fortymile Canyon, the borehole penetrated approximately
487.7 m (1,600 ft) of tuff assigned to the Timber Mountain Group that appears to have been
erupted after the Ammonia Tanks Tuff and the formation of the Ammonia Tanks caldera. The
well reached TD in intracaldera Ammonia Tanks Tuff.
Drilling of Well ER-EC-2A began in rhyolitic lava of the rhyolite of Beatty Wash, a subunit of
the Beatty Wash Formation. The borehole penetrated approximately 209.1 m (686 ft) of lava,
including intervals of pumiceous and vitrophyric lava. The assignment of this lava unit to the
rhyolite of Beatty Wash is based mainly on the presence of significant amounts of biotite,
hornblende, and sphene, and the absence of quartz. Below the lava, the well penetrated 712.9 m
(2,339 ft) of nonwelded tuff and minor welded ash-flow tuff. The upper half of this interval is
assigned to the rhyolite of Beatty Wash because of its similarity in petrographic character to
outcrop samples of rhyolite of Beatty Wash collected within the northern Timber Mountain moat
area (Warren, 2000). The overall petrographic character of the lower half of the interval is
similar to that of the overlying interval, but the lower portion contains quartz (although in
abundances too low for Timber Mountain Group units) and has more felsic phenocrysts and
mafic minerals. Based on these characteristics, this lower interval can be assigned to the Beatty
Wash Formation, but not to any subunit of the formation.
Below the rhyolite of Beatty Wash is a complex and diverse assemblage of rocks that consist of
interbedded tuffs, fine-grained sedimentary and tuffaceous sedimentary rocks that resemble
lacustrine deposits, and possibly chemically precipitated hydrothermal deposits. This interval is
21.3 m (70 ft) thick and occurs at the base of the Volcanics of Fortymile Canyon. It is assigned
to the Volcanics of Fortymile Canyon based on the scarcity of quartz in the tuffaceous units. The
only other occurrence in the area of similar rocks in the same stratigraphic position was reported
by Fridrich et al. (1999) on Oasis Mountain, approximately 19.3 km (12 mi) southwest of
Well ER-EC-2A.
Below the Volcanics of Fortymile Canyon, Well ER-EC-2A penetrated 490.4 m (1,609 ft) of
mostly poorly welded tuff assigned to the Timber Mountain Group. The stratigraphic
assignment of this interval is based mainly on a dramatic increase in quartz, and its stratigraphic
position below Volcanics of Fortymile Canyon and above mafic-rich Ammonia Tanks Tuff. A
more precise assignment is hindered by the high degree of alteration present, but the interval
4-8
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4-10
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4-11
likely includes post-Ammonia Tanks Tuff units such as tuff of Crooked Canyon and tuff of
Buttonhook Wash, and/or debris flows from the lower part of the Ammonia Tanks Tuff. Visual
evaluation of samples and data from geophysical logs suggest that the interval consists of a
monotonous sequence of poorly welded tuffs. However, petrographic analyses suggest that
much of the interval may be moderately welded.
Drilling of Well ER-EC-2A was terminated in moderately welded ash-flow tuff of the mafic-rich
Ammonia Tanks Tuff. This stratigraphic assignment is based on the unit’s mafic-rich character,
high sanidine content, the presence of quartz, and the absence of monazite which is ubiquitous in
the underlying Rainier Mesa Tuff (Warren, 2000).
The relative position, extent, and thickness of the stratigraphic units near Well ER-EC-2A are
illustrated on the cross section in Figure 4-4. As shown on the cross section, Well ER-EC-2A is
interpreted to be located within the structural margins of both the Rainier Mesa and Ammonia
Tanks calderas (which are interpreted to be coincident in the northwestern region of the TMCC).
This interpretation is based on data from nearby drill holes as well as from regional analyses of
surface geology and gravity data (DOE/NV, 2000a, b, c; Mankinen et al., 1999).
Because Well ER-EC-2A was terminated in Ammonia Tanks Tuff and thus did not reach the
Rainier Mesa Tuff, data from the hole does not provide information on the location of the well
relative to the Rainier Mesa caldera. However, the unusually low elevation for the top of the
mafic-rich Ammonia Tanks Tuff in Well ER-EC-2A, and the unusually thick sequence of post-
Ammonia Tanks Tuff rocks suggest that this location is within the Ammonia Tanks caldera and
that collapse was unusually deep in this portion of the caldera. The extent of collapse is quite
evident when compared with Well ER-EC-4, located approximately 5.6 km (3.5 mi) west-
northwest of Well ER-EC-2A and outside of the TMCC (DOE/NV, 2000b). The top of the
Ammonia Tanks Tuff at Well ER-EC-2A is 815.6 m (2,676 ft) lower in elevation than the top at
Well ER-EC-4. Consequently, post-Ammonia Tanks Tuff units at Well ER-EC-2A are 858.9 m
(2,818 ft) thicker than at Well ER-EC-4. Also supporting the interpretation of unusually deep
caldera collapse in the area of Well ER-EC-2A is the presence of lacustrine deposits at the base
of the Volcanics of Fortymile Canyon that probably represent the development of a caldera lake.
As mentioned previously, the only other known occurrence in the region of similar units in a
similar stratigraphic position is on Oasis Mountain. Fridrich et al. (1999) suggested that the
4-13
lacustrine and volcanic rocks that make up Oasis Mountain were deposited within the margins of
the Rainier Mesa caldera and were later transported westward to their present location outside the
caldera along a shallow detachment fault.
4.2.2 Alteration
Alteration has a significant effect on both the general hydraulic character of volcanic rocks and
on how radionuclides migrate through these rocks. The predominant type of mineralogic
alteration observed in each stratigraphic unit encountered in Well ER-EC-2A is illustrated on
Figure 4-3. Above the depth of 227.4 m (746 ft), the rocks are mostly devitrified, with lesser
amounts of silicic alteration and unaltered (vitric) rocks. This interval corresponds to the interval
of lava assigned to the rhyolite of Beatty Wash. Below the depth of 227.4 m (746 ft), the rocks
are zeolitic to 399.3 m (1,310 ft) and consist of nonwelded tuff. All rocks below 227.4 m
(746 ft) contain a quartzo-feldspathic assemblage of alteration minerals, indicating higher-
temperature, hydrothermal alteration. This alteration interval includes nonwelded tuffs, welded
ash-flow tuffs, and tuffaceous sedimentary rocks.
4.3 Predicted Versus Actual Geology
The predicted geology for Well ER-EC-2A (IT, 1998) was based on geologic maps by O’Conner
et al. (1966), Byers et al. (1976), and Wahl et al. (1997). The geology of Well UE-18r
(Carr et al., 1968) was also evaluated, as the well was thought to be in a similar volcanic and
structural setting. A comparison of the predicted and the actual (preliminary) stratigraphy is
provided in Figure 4-5. The well was predicted to penetrate approximately 229 m (750 ft) of
rhyolite lava of the Beatty Wash Formation, overlying a minor thickness of bedded tuff also of
the Beatty Wash Formation. Well ER-EC-2A penetrated the predicted thickness of lava
(227.4 m [746 ft]), but encountered more than 734.3 m (2,409 ft) of mostly nonwelded tuff of the
Volcanics of Fortymile Canyon below the lava. The much greater than predicted thickness of
tuff below the lava appears to be the result of deposition within a deep volcanic depression
resulting from much greater collapse of the northwestern portion of the Ammonia Tanks caldera.
The occurrence of lacustrine deposits in Well ER-EC-2A was not predicted, but their presence
would be expected if a caldera lake developed within the deep depression created by the caldera
collapse. The deep collapse of the Ammonia Tanks caldera in the area of ER-EC-2A also
resulted in the accumulation of a considerable thickness of Timber Mountain rocks that post-date
the Ammonia Tanks Tuff. These rocks were not predicted to occur at the ER-EC-2A site, as
such a deep collapse was not predicted.
4-15
The Ammonia Tanks Tuff was encountered at the depth of 1,452.1 m (4,764 ft) in
Well ER-EC-2A, which is 1,208.2 m (3,964 ft) deeper than predicted prior to drilling. The well
was predicted to penetrate a complete section of the Ammonia Tanks Tuff before encountering
Timber Mountain landslide breccia and Rainier Mesa Tuff. However, because the Ammonia
Tanks Tuff was encountered so much deeper than predicted, the well was still within the
Ammonia Tanks Tuff when drilling ended at 1,516.1 m (4,974 ft) just above the planned TD of
1,524.0 m (5,000 ft).
Prior to drilling of Well ER-EC-2A, it was uncertain whether this location was within the
Ammonia Tanks caldera. Interpretation of geologic data from the well and recent gravity data
(Mankinen et al., 1999) now strongly suggest that Well ER-EC-2A was drilled within the caldera
margin. Although only 64.0 m (210 ft) of Ammonia Tanks Tuff was penetrated before drilling
was halted, the rocks encountered are strongly welded and are from the upper mafic-rich
member, indicating that only the upper portion of what is likely a very thick intracaldera
sequence of the Ammonia Tanks Tuff was penetrated. Analysis of regional gravity data suggests
that basement rocks occur at the deepest levels in the northern portion of the TMCC (Mankinen
et al., 1999), consistent with deeper collapse. However, deeper basement rocks in the northern
portion of the caldera could also be the result of less post-caldera resurgence in this area.
Landslide breccia related to caldera development was predicted to be encountered between the
Ammonia Tanks and Rainier Mesa Tuffs and within the Rainier Mesa Tuff. As discussed above,
the well reached TD in Ammonia Tanks Tuff, well above the predicted position of the landslide
breccia. However, such deep collapse of the Ammonia Tanks caldera suggested by drill hole and
geophysical data likely resulted in a very high, steep, and initially unstable Ammonia Tanks
caldera margin north and west of Well ER-EC-2A. It is likely that such a margin would generate
landslides that would result in the deposition of landslide breccia deposits within the Ammonia
Tanks caldera. Although no landslide deposits were definitively identified within the Ammonia
Tanks or post-Ammonia Tanks rocks in Well ER-EC-2A, petrographic analysis of drill cuttings
from the depth of 1,243.6 m (4,080 ft) in Well ER-EC-2A shows a mixture of lithologies which
may represent a landslide deposit originating from the lower portion of the Ammonia Tanks Tuff
(Warren, 2000).
There has been some speculation among project scientists that the interval of fine-grained
sedimentary rocks encountered at the depth of 946.1 to 961.6 m (3,104 to 3,155 ft) in
Well ER-EC-2A represents a slide block of Paleozoic rocks. However, regional geologic and
4-16
geophysical analysis indicate that it is unlikely that nearby Paleozoic rocks are at high enough
levels outside the caldera complex to provide landslide debris at the depth in question in Well
ER-EC-2A. Also, petrographic analyses of these rocks indicate that it is highly unlikely that
these rocks represent Paleozoic units (Warren, 2000).
4.4 Hydrogeology
The rocks of Well ER-EC-2A have been subdivided into hydrogeologic units, as illustrated in
Figure 4-3. A preliminary interpretation of the distribution of these units is shown in cross
section on Figure 4-6. Because of the limited amount of data from the area around
Well ER-EC-2A, and the difficulty in predicting the lateral continuity of hydraulic properties of
volcanic rocks, the cross section is rather conjectural. However, it does illustrate the
complexities associated with the distribution of hydrogeologic units in caldera settings such as
the Oasis Valley area.
The dominant hydrogeologic unit in Well ER-EC-2A is tuff confining unit, consisting of mostly
quartzo-feldspathic, poorly welded tuff, and comprising approximately 80 percent of the rocks
penetrated by the well. Analysis of water production data during drilling indicates that the rocks
assigned as tuff confining unit (based on lithology and alteration) produced water at a rate of
about 946 lpm (250 gpm) to possibly as much as 2,271 lpm (600 gpm). Fracture analysis of the
borehole image log from Well ER-EC-2A suggests that water production from tuff confining
units is confined to discrete fractured intervals. Thus, data from Well ER-EC-2A indicates that
although primary permeability is probably low in tuff confining units, these hydrogeologic units
can at times produce substantial water from fractured intervals. It should also be noted that the
high degree of alteration present obscures lithologic characteristics and makes lithologic
identification difficult and somewhat uncertain. Thus, the water production observed within the
tuff confining units may be coming from rocks that are substantially more welded (and thus more
fractured) than described. For example, water production during drilling increased from
approximately 2,271 lpm (600 gpm) to more than 3,028 lpm (800 gpm) near the bottom of the
well where strongly welded Ammonia Tanks Tuff is present.
See the discussion of the general hydraulic properties of the hydrogeologic units, including,
expected in Well ER-EC-2A in IT (1998), Section B.6.2 and Table B.6.1. Planned hydrologic
testing in the Well ER-EC-2A may verify the actual hydraulic character of the units exposed in
the screened intervals of the well.
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5-1
5.0 Hydrology
5.1 Preliminary Water-Level Information
Well ER-EC-2A is located on the west flank of an apparent northeast-trending groundwater
trough that extends from the Oasis Valley discharge area through the Well ER-EC-2A area, and
beneath Pahute Mesa. Water-level data are sparse in this area, so hydrologic data from
Well ER-EC-2A are expected to aid in understanding regional groundwater flow.
The elevation of the water table at Well ER-EC-2A was projected to be approximately 1,276 m
(4,187 ft), as derived from sparse hydrologic data for this region (IT, 1998). Based on the pre-
construction estimate of surface elevation at the site, depth to water was expected at
approximately 205 m (673 ft) (IT, 1998). During drilling, water production was first noted at a
depth of approximately 265.8 m (872 ft), and fluid depths between 230.4 and 257.3 m (756 and
844 ft) were obtained from various geophysical logs run on January 27, 2000 and
February 7-8, 2000, before the completion string was installed. A preliminary composite fluid
level (depth) of 228.0 m (747.9 ft) was measured by IT on April 14, 2000 (IT, 2000), which
seems to indicate slow recovery (gradually decreasing depth to water over time). Based on this
preliminary fluid depth and the as-built surface elevation of 1,494.1 m (4,901.9 ft), the fluid level
elevation at Well ER-EC-2a is 1,266.1 m (4,154.0 ft). This is approximately 10 m (33 ft) below
the predicted elevation of 1,276 m (4,187 ft). A transducer for monitoring of the water level was
not installed at the time of completion.
5.2 Water Production
Water production was estimated during drilling of Well ER-EC-2A on the basis of LiBr dilution
data as measured by IT field personnel. Nonwelded to moderately welded ash-flow tuffs of the
Timber Mountain Group were the primary water-producing units at this location, however,
measurable water production (approximately 38 lpm [10 gpm]) began at the depth of about
265.8 m (872 ft) within nonwelded rhyolite of Beatty Wash. The production rate remained
relatively low and constant to the depth of about 399.3 m (1,310 ft) where it began to increase.
The decision was made to stop drilling and install a surface casing at the depth of about 418.2 m
(1,372 ft), where water production had reached about 379 lpm (100 gpm). When drilling
resumed, the production rate dropped back to about 95 lpm (25 gpm) but at the depth of about
464.8 m (1,525 ft) it began steadily to increase, reaching 757 lpm (200 gpm) at a depth of
approximately 556.3 m (1,825 ft), still within nonwelded tuff. Water production then increased
very gradually until, between the depths of 929.6 and 944.9 m (3,050 and 3,100 ft), near the base
5-2
of a nonwelded ash-flow tuff of the Beatty Wash Formation and within tuffaceous sedimentary
deposits of the Volcanics of Fortymile Canyon (undivided), it increased dramatically from about
1,325 lpm (350 gpm) to about 2,271 lpm (600 gpm). Water production remained fairly steady
within the underlying nonwelded tuffs of the Fortymile Canyon and Timber Mountain Groups.
At the depth of about 1,341.1 m (4,400 ft), still within the Timber Mountain Group, water
production began to increase again, reaching the maximum measured during drilling, of about
3,407 lpm (900 gpm) from the depth of 1,505.7 m (4,940 ft) to the TD in moderately welded
Ammonia Tanks Tuff. Estimated water production rates are presented graphically in
Appendix A-1.
5.3 Preliminary Flow Meter Data
Flow meter data, along with temperature, electrical conductivity (EC), and pH measurements,
can be used to characterize borehole fluid variability, which may indicate inflow and outflow
zones. The design of the completion string for Well ER-EC-2A was based in part on field
evaluation of data from these measurements.
DRI personnel made measurements with their thermal flow meter (TFM) tool at five locations
between the depths of 502.9 and 1,082.0 m (1,650 and 3,550 ft) before the completion string was
installed. Preliminary analysis of a plot of the discrete TFM data points indicates a downward
flow of water within the borehole at all stations. However, flow velocities could not be measured
because they exceeded the calibration range of the instrument, so DRI then ran an ambient full-
bore flow meter and temperature log, or “spinner” log, from 396.2 to 1,513.3 m (1,300 to
4,965 ft). This log also indicated downward flow in the borehole. Preliminary comments by
DRI on the log plot indicate inflow between the depths of 412.7 and 432.8 m (1,354 and
1,420 ft), 524.3 and 670.6 m (1,720 and 2,200 ft), and between 899.2 and 1,036.3 m (2,950 and
3,400 ft). Outflow of fluid from the hole was reported at 1,066.8 m (3,500 ft) and between
1,447.8 and 1,493.5 m (4,750 and 4,900 ft).
In addition, DRI ran a chemistry log, which included measurements of temperature, EC, and pH,
from 257.3 to 1,515.8 m (844 to 4,973 ft). Groundwater temperature gradually increased from
the minimum reading of 34.4 degrees Celsius (C) (93.9 degrees Fahrenheit [F]) at the top of the
fluid column to the depth of approximately 1,066.8 m (3,500 ft). Below that depth the
temperature increased somewhat more steeply, and continued to rise to the borehole maximum of
49.6 degrees C (121.3 degrees F) at the depth of 1,515.8 m (4,973 ft). Plots of the TFM and
chemistry log data are reproduced in Appendix D.
5-3
5.4 Preliminary Groundwater Characterization Samples
Following geophysical logging, DRI collected preliminary groundwater characterization samples
within the open borehole. Two six-liter samples were collected at the depth of 1,066.8 m
(3,500 ft). Analytical data from these initial samples, collected before formal well development,
will provide a basis for comparison with future groundwater chemistry data.
5-4
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6-1
6.0 Precompletion and Open-Hole Development
The only precompletion development conducted in Well ER-EC-2A consisted of circulating fluid
for 30 minutes to clean the borehole, and developing the well by using five compressors to blow
water out of the hole. This process was conducted immediately after TD was reached and prior
to geophysical logging.
6-2
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7-1
7.0 Well Completion
7.1 Introduction
Well completion refers to the installation in a borehole of a string of pipe or casing that is slotted
or screened at one or more locations along its length. The completion process also typically
includes emplacement of backfill materials around the casing, with coarse fill such as gravel
adjacent to the open intervals and impervious materials such as cement between the open
intervals to isolate them. The casing serves as a conduit for insertion of a pump in the well, for
inserting devices for measuring fluid level, and for sampling, so that accurate potentiometric and
water chemistry data can be collected from known portions of the borehole.
Completion activities at Well ER-EC-2A took place on February 10-14, 2000, though a
submersible pump was installed later for hydrologic testing. Figure 7-1 is a schematic of the
final well-completion design for Well ER-EC-2A, Table 7-1 is a construction summary for the
well, and Figure 7-2 shows a plan view and profile of the wellhead surface completion. Data for
this section were obtained from daily operations and activity reports, casing records, and
cementing records provided by the BN Drilling Department. Information from IT’s well data
report (IT, 2000) was also consulted for preparation of this section.
7.2 Well Completion Design
The final completion design differs slightly from the proposed design, as described in the
following paragraphs.
7.2.1 Proposed Completion Design
The original completion design (IT, 1998) was based on the assumption that Well ER-EC-2A
would penetrate a thick welded-tuff aquifer in the Rainier Mesa Tuff. The well was planned to
be completed with a single casing string consisting of 5½-in. stainless steel casing, with every
other joint slotted, suspended on carbon-steel 7e-in. casing. The primary goal was to obtain
satisfactory completion within this welded-tuff aquifer, but the proposed completion design also
called for the isolation (using non-slotted casing) of low transmissivity zones within the
completion interval, if such zones could be identified.
7-3
Table 7-1Well ER-EC-2A Completion String Construction Summary
Casing TypeConfiguration
mete rs (feet)Cement Sand/Gravel
7e-in. carbon-steelproduction casing withinternal epoxy coating
0 to 415.7(0 to 1,364.0)
BlankType II
210.9 to 498.3(692 to 1,635)
None7e-in. to 5½-in. cross-over sub, carbon-steel,
with stainless-steeldouble pin
415.7 to 416.5(1,364.0 to 1,366.4)
Blank
5½-in.Stainless-steel
production casing
416.5 to 1,512.0(1,366.4 to 4,960.5)
Blank416.5 to 520.3
(1,366.4 to 1,707.1)
Type II
681.5 to 788.5(2,236 to 2,587)
832.1 to 922.0(2,730 to 3,025
1,098.2 to 1,344.2(3,603 to 4,410)
20/40 Sand
498.3 to 504.7(1,635 to 1,656)
922.0 to 928.7(3,025 to 3,047)
1,344.2 to 1,353.9(4,410 to 4,442)
6-9 Sand
504.7 to 508.4(1,656 to 1,668)
928.7 to 931.8(3,047 to 3,057)
1,353.9 to 1,357.6(4,442 to 4,454)
3/8-in. x 4 Gravel
508.4 to 681.5(1,668 to 2,236)
788.5 to 832.1(2,587 to 2,730) a
931.8 to 1,098.2(3,057 to 3,603)
1,357.6 to 1,514.6(4,454 to 4,969)
11 consecutive slotted joints520.3 to 664.1
(1,707.1 to 2,178.8)
Blank664.1 to 937.8
(2,178.8 to 3,076.7)
11 consecutive slotted joints
937.8 to 1,081.6(3,076.7 to 3,548.6)
Blank 1,081.6 to 1,367.7(3,548.6 to 4,487.2)
10 consecutive slotted joints
1,367.7 to 1,498.3 (4,487.2 to 4,915.8)
Blank and bull-nosed1,498.3 m to 1,512.0( 4,915.8 to 4,960.5)
a Gravel section not adjacent to slotted interval
7-5
7.2.2 As-Built Completion Design
The design of the Well ER-EC-2A completion was determined through consultation with
members of the UGTA TWG, on the basis of on-site evaluation of data such as lithology and
water production, drilling data (lost circulation, etc.), data from various geophysical logs, and
from flow meter and water chemistry logs.
The as-built completion design for Well ER-EC-2A provides access to three aquifers
(Figure 7-1). The composition of the string summarized here is detailed on Table 7-1, and the
casing materials are listed in Appendix A-2. The lower section of the completion string, from
1,512.0 to 416.5 m (4,960.5 to 1,366.4 ft), is type SSTP304 stainless-steel casing with an outside
diameter of 14.13 cm (5.563 in.) and an inside diameter of 12.82 cm (5.047 in.). The top of the
5½-in. casing is approximately 101 m (331 ft) below the static fluid level. The bottom 0.67-m
(2.2-ft) joint is a blank bull-nose to serve as a sediment sump. Above the 5½-in. casing, a
0.73-m (2.4-ft) long cross-over sub serves as the transition to the upper part of the string, which
is 7e-in. carbon-steel production casing with an internal epoxy coating.
The lowest slotted interval, 1,367.7 to 1,498.3 m (4,487.2 to 4,915.8 ft), is open to mainly
welded-tuff aquifer lithologies of the Timber Mountain Group. (See Figure 4-3 for an
illustration of gravel-pack locations relative to hydrogeologic units.). This casing interval
consists of 10 consecutive slotted joints. The second slotted interval, 937.8 to 1,081.6 m
(3,076.7 to 3,548.6 ft), consists of 11 consecutive slotted joints. It is open to tuff confining unit
lithologies consisting of nonwelded tuff and an interval of reworked tuff with tuffaceous siltstone
and reworked tuff that seemed to be a significant water producer during drilling. The uppermost
slotted interval, 520.3 to 664.1 m (1,707.1 to 2,178.8 ft), also consists of 11 consecutive slotted
joints and is open to tuff confining unit lithologies of the Volcanics of Fortymile Canyon.
The openings in each slotted casing joint are 0.198 cm (0.078 in.) wide and 5.1 cm (2 in.) long,
cut in rings of 18 slots (spaced 20 degrees apart around the joint). The rings are spaced 15.2 cm
(6 in.) apart, and the longitudinal centers of the slots in each ring are staggered 10 degrees from
the slot centers in the next ring. No slots are cut within 0.6 m (2 ft) of the ends of the slotted
joints to assure that the strength of the pipe near the connections is not degraded.
7-6
7.2.3 Rationale for Differences between Actual and Proposed Well Design
The proposed well design was based on an expected geologic setting in which a thick welded-
tuff aquifer in the Ammonia Tanks Tuff would be present in the upper part of the hole. Below
the Ammonia Tanks Tuff, two intervals of welded-tuff aquifer of the Rainier Mesa Tuff were
expected, separated by a section of Timber Mountain landslide breccia. The proposed well
design included the construction of one completion zone that encompassed both expected
intervals of welded Rainier Mesa Tuff in the lower fifth of the borehole.
Rainier Mesa Tuff was not encountered in Well ER-EC-2A, which reached TD in the upper part
of the Ammonia Tanks Tuff. However, several water-producing units were encountered,
including nonwelded to moderately welded tuff, tuffaceous siltstone, and reworked tuff of the
Volcanics of Fortymile Canyon Group, and nonwelded and welded tuff of the Timber Mountain
Group. The completion design was modified to include completion zones in these aquifers, and
intervening intervals were isolated by blank sections. However, the basic plan of installing a
single string consisting of larger diameter carbon-steel casing above the water table and smaller
diameter stainless-steel casing in the saturated zone was accomplished.
7.3 Well Completion Method
A “tremie” line and the completion string were landed after a brief period of circulation and
conditioning of the hole. The three completion zones were gravel-packed and isolated from each
other with sand and cement barriers. One additional gravel layer (instead of cement) was placed
adjacent to a blank interval (Figure 7-1; Table 7-1) to save time waiting for cement deliveries.
Caliper logs were used to calculate the volumes of stemming materials needed during well
completion. Well-construction materials were inspected in accordance with relevant procedures;
standard decontamination procedures were employed to prevent the introduction of contaminants
into the well.
The filter pack around each open interval consists of 0.95-cm (d-in.) by 4-mesh washed pea
gravel, with 6-9 Colorado silica sand directly above the gravel, and 20/40 sand on top of the
6-9 sand. In this stemming design, developed by the UGTA program at the NTS, the layer of
20/40 sand serves as a barrier to any fluids that might seep from the cement above, preventing
cement fluids from contaminating the groundwater (fluids from the cement would have the effect
of drastically raising the pH of the groundwater). The underlying layer of 6-9 sand prevents the
20/40 sand from infiltrating the gravel-packed interval. All cement used in stemming the
completion string was Type II Portland cement with no additives. A clear-water pre-flush and
7-7
back-flush were made at each stage of emplacement. Gravel, sand, and cement were emplaced
through a 2f-in. Hydril® tremie line that was withdrawn as the completion process progressed.
A Nuclear Annulus Investigation Log (“NAIL”) was used to monitor the emplacement of
stemming materials. As-built positions of the well materials are shown on Figure 7-1 and listed
in Table 7-1.
Stemming of the hole began with the first stage of gravel emplaced from 1,514.6 to 1,357.6 m
(4,969 to 4,454 ft) on top of 1.5 m (5 ft) of fill at the bottom of the hole, and adjacent to the
lowest slotted interval. This gravel pack is topped by a sand barrier to the depth of 1,344.2 m
(4,410 ft), followed by cement, poured in two stages up to 1,098.2 m (3,603 ft). A second layer
of gravel was placed between the depths of 1,098.2 and 931.8 m (3,603 and 3,057 ft), adjacent to
the middle slotted interval; this gravel was topped with sand to the depth of 922.0 m (3,025 ft),
and cement, poured in two stages, to the depth of 832.1 m (2,730 ft). The next gravel section,
adjacent to a blank casing interval, is located between 832.1 and 788.5 m (2,730 and 2,587 ft),
and is capped by cement, poured in two stages, to 681.5 m (2,236 ft). The last gravel-packed
zone was placed outside the uppermost slotted interval between the depths of 681.5 and 508.4 m
(2,236 and 1,668 ft), and was capped with sand to the depth of 498.3 m (1,635 ft). The final
cemented section extends to the depth of 210.9 m (692 ft).
The drill rig was released after cementing was completed. Hydrologic testing was planned as a
separate effort, so a pump was not installed in the well and no well-development or pumping
tests were conducted immediately after completion.
7-8
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8-1
8.0 Actual versus Planned Costs and Scheduling
The BN cost model developed for Well ER-EC-2A was based on drilling to the planned TD of
1,524.0 m (5,000 ft). The drilling program baseline projected that it would require 36 days to
accomplish drilling of the surface and main holes, logging, and completion for the well,
assuming the conductor hole would already have been constructed by BN. The actual time spent
to drill the main and surface holes, and install the completion string in Well ER-EC-2A was
25 days. Drilling of the surface hole and installation of the 13d- casing proceeded as expected.
However, drilling of the production hole and installation of the completion casing took
approximately 11 days less time than predicted. A graphical comparison, by day, of planned and
actual well-construction activities is presented in Figure 8-1.
The cost analysis for Well ER-EC-2A begins with construction of the conductor hole by BN and
the cost of mobilizing the UDI drill rig to the Well ER-EC-2A site. The cost of building roads,
the drill pad, and sumps is not included, and the cost of well-site support by IT is not included.
The total construction cost for Well ER-EC-2A includes all drilling costs: charges by the drilling
subcontractor; charges by other support subcontractors (including compressor services, drilling
fluids, bits, casing services, down-hole tools and, and geophysical logging); and charges by BN
for mobilization and demobilization of equipment, partial construction of the conductor hole,
cementing services, completion materials, radiation technicians, inspection services, and
geotechnical consultation.
The total planned cost for Well ER-EC-2A was $2,307,869. The actual cost was $1,848,201, or
20 percent less than the planned cost. Figure 8-2 presents a comparison of the planned
(“baseline”) and actual costs, by day, for drilling and completing Well ER-EC-2A. The quicker
than expected drilling time for construction of the production hole was main source of the cost
savings realized on this well.
74
4,201
4,676
4,9744,915
65 226403
620
1,0511,372
1,926
2,626
3,190
3,5483,794
0
1,000
2,000
3,000
4,000
5,000
6,000
20-Jan 21-Jan 22-Jan 23-Jan 24-Jan 25-Jan 26-Jan 27-Jan 28-Jan 29-Jan 30-Jan 31-Jan 1-Feb 2-Feb 3-Feb 4-Feb 5-Feb 6-Feb 7-Feb 8-Feb 9-Feb 10-Feb 11-Feb 12-Feb 13-Feb 14-Feb 15-Feb 16-Feb 17-Feb 18-Feb 19-Feb 20-Feb 21-Feb 22-Feb 23-Feb 24-Feb 25-Feb
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
Sequential Day Number and Date
Dep
th in
Fee
t
Planned Actual
Drill 17-1/2 inch Hole
Run Geophysical Logging Services
Run and Cement13-3/8 inch Casing
Drill 12-1/4 inchProduction Hole
Run Geophysical Logging Services Install Production
CasingStem and Cement Casing
`
8-2
Figure 8-1 Planned versus Actual Construction Progress for Well ER-EC-2A
$2,307,869
$1,848,201
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
20-Jan
21-Jan
22-Jan
23-Jan
24-Jan
25-Jan
26-Jan
27-Jan
28-Jan
29-Jan
30-Jan
31-Jan
1-Feb
2-Feb
3-Feb
4-Feb
5-Feb
6-Feb
7-Feb
8-Feb
9-Feb
10-Feb
11-Feb
12-Feb
13-Feb
14-Feb
15-Feb
16-Feb
17-Feb
18-Feb
19-Feb
20-Feb
21-Feb
22-Feb
23-Feb
24-Feb
25-Feb
26-Feb
27-Feb
28-Feb
29-Feb
30-Feb
31-Feb
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
Date and Sequential Day Number
Cos
t in
Dol
lars
PLANNED ACTUAL
Actual cost for installation of conductor casingand mobilization, as of beginning of work bydrilling subcontractor, 01/20/2000
$441,651
Actual Costs
Baseline Task Plan Costs
8-3
Figure 8-2 Planned versus Actual Cost for Constructing Well ER-EC-2A
8-4
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9-1
9.0 Summary, Recommendations, and Lessons Learned
9.1 Summary
Subcontractor activities at Well ER-EC-2A commenced on January 21, 2000, and concluded on
February 14, 2000, when the TD of 1,516.1 m (4,974 ft) was reached. After geophysical
logging, the completion string was installed and gravel-packed, and the hole was stemmed to the
depth of 210.9 m (692 ft) on February 11-14, 2000. Crews worked on a 7-days-per-week,
24-hours-per-day schedule for most of the operation. Twenty-five working days were expended
to drill the surface and main holes, conduct geophysical logging, and install the completion
string. The only problem encountered during construction of Well ER-EC-2A was a 10.5-hour
delay during drilling due to a fluid-management issue.
No radionuclides above background were encountered in the groundwater produced from
Well ER-EC-2A. Preliminary (field-monitoring) data indicated no lead above permitted levels
for dissolved lead in the drilling effluent.
IT personnel measured the depth to fluid at 228.0 m (747.9 ft) on April 14, 2000, two months
after the completion string was installed.
Composite drill cuttings were collected every 3 m (10 ft) from 36.6 m (120 ft) to TD. Eighty-
one sidewall samples were collected in the interval 212.8 to 1,508.2 m (698 to 4,948 ft).
Geophysical logging was conducted in the upper part of the hole before installation of the surface
casing, and in the lower part of the hole before installation of the completion string. Some of
these logs were used to aid in construction of the well, while others help to verify the geology
and determine the hydrologic characteristics of the rocks.
A single completion string with three gravel-packed, slotted intervals, was installed in
Well ER-EC-2A. A string of 5½-in. stainless-steel casing installed below the water table is
suspended from 7e-in. carbon-steel casing (with an internal epoxy coating) which extends to the
surface. The open intervals in the 5½-in. casing are centered within the gravel-pack intervals that
are located at 508.4 to 681.5 m (1,668 to 2,236 ft); 931.8 to 1,098.2 m (3,057 to 3,603 ft); and
1,357.6 to 1,514.6 m (4,454 to 4,969 ft). These intervals are open to bedded and nonwelded tuff
of the rhyolite of Beatty Wash and the Beatty Wash Formation, reworked tuff, tuffaceous
siltstone with mostly nonwelded tuff of the Timber Mountain Group, and welded-tuff aquifer
lithologies of the Ammonia Tanks Tuff.
9-2
9.2 Recommendations
The planned pump installation, well development, groundwater sampling, and hydrologic testing
must be conducted at Well ER-EC-2A to accomplish the remaining objectives for this well-
construction effort. In addition, after all the planned PM-OV wells are drilled, geologic and
hydrologic data must be evaluated and interpretations of the area hydrogeology updated and
inserted into the UGTA hydrologic model. This process, followed by analysis of the updated
model, will allow more precise characterization of groundwater flow direction and velocity in the
region between the nuclear testing areas of Pahute Mesa and the Oasis Valley discharge area.
9.3 Lessons Learned
The efficiency of drilling and constructing wells to obtain hydrogeologic data in support of the
UGTA project continues to improve as experience is gained with each new well. No new lessons
were learned during the construction of Well ER-EC-2A, which was the eighth well in this
program of drilling in the Oasis Valley area,.
10-1
10.0 References
Bechtel Nevada. 1999. Western Pahute Mesa/Oasis Valley (WPM-OV) Investigation Wells Site-Specific Health and Safety Plan (SSHASP). February 1999. Las Vegas, NV.
Bechtel Nevada. 2000. Drilling Program for Underground Test Area (UGTA) Western PahuteMesa/Oasis Valley (WPM-OV) Investigation Well ER-EC-2A - Original. Drilling Work PlanNumber D-001-002.00. January 18, 2000. Las Vegas, NV.
BN, see Bechtel Nevada.
Byers, F. M., Jr., W. J. Carr, R. L. Christiansen, P. W. Lipman, P. P. Orkild, and W. D. Quinlivan. 1976. “Geologic Map of the Timber Mountain Caldera Area, Nye County, Nevada.” U.S.Geological Survey Miscellaneous Investigations Map I-891, scale 1:48,000 Reston, VA.
Carr, W. J., F. M. Byers, and E. C. Jenkins. 1968. Geology of Drill Hole UE18r, TimberMountain Caldera, Nevada Test Site. U.S. Geological Survey Technical Letter: SpecialStudies-69. Denver, CO.
DOE/NV, see U.S. Department of Energy, Nevada Operations Office.
Ferguson, J. F., A. H. Cogbill, and R. G. Warren. 1994. “A Geophysical-Geologic Transect of theSilent Canyon Caldera Complex, Pahute Mesa, Nevada.” In Journal of Geophysical Research,v. 99, n. 33, pp. 4,323-4,339.
Fridrich, C. J., S. A. Minor, and E. A. Mankinen. 1999. Geologic Evaluation of the Oasis ValleyBasin, Nye County, Nevada. U.S. Geological Survey Open-File Report 99-533-A. Denver,CO.
IT, see IT Corporation.
IT Corporation. 1998. FY99 Western Pahute Mesa - Oasis Valley Hydrogeologic InvestigationWells Drilling and Completion Criteria, ITLV/13052-049. Las Vegas, NV.
IT Corporation. 2000. Written communication prepared for DOE/NV. Subject: “Western PahuteMesa - Oasis Valley: ER-EC-2A Well Data Report,” July 2000. Las Vegas, NV.
Mankinen, E. A., T. G. Hildenbrand, G. L. Dixon, E. H. McKee, C. J. Fridrich, and R. J. Laczniak. 1999. Gravity and Magnetic Study of the Pahute Mesa and Oasis Valley Region, Nye County,Nevada, U. S. Geological Survey Open-File Report 99-303. Menlo Park, CA
O’Connor, J. T., R. E. Anderson, and P. W. Lipman. 1966. “Geologic Map of the Thirsty CanyonQuadrangle, Nye County, Nevada.” U.S. Geological Survey Geologic Quadrangle MapGQ-524, scale 1:24,000. Washington, D.C.
10-2
Sawyer, D. A., J. J. Fleck, M. A. Lanphere, R. G. Warren, and D. E. Broxton. 1994. “EpisodicCaldera Volcanism in the Miocene Southwest Nevada Volcanic Field: Revised StratigraphicCaldera Framework, 40Ar/39Ar Geochronology, and Implications for Magmatism andExtension.” Geological Society of America Bulletin, v. 67, n. 10, pp. 1,304-1,318.
U.S. Department of Energy, Nevada Operations Office. 1996a. Attachment 1, “FluidManagement Plan for the Underground Test Area Subproject.” In Underground Test AreaSubproject Waste Management Plan, Revision 1, DOE/NV--343. Las Vegas, NV.
U.S. Department of Energy, Nevada Operations Office. 1996b. Underground Test AreaSubproject Waste Management Plan, Rev. 1, DOE/NV--343. Las Vegas, NV.
U.S. Department of Energy, Nevada Operations Office. 1998. Nevada Environmental RestorationProject Health and Safety Plan, Revision 3, February 1998. Las Vegas, NV.
U.S. Department of Energy, Nevada Operations Office. 2000a. Completion Report forWell ER-EC-6. DOE/NV/11718–360. Las Vegas, NV.
U.S. Department of Energy, Nevada Operations Office. 2000b. Completion Report forWell ER-EC-1. DOE/NV/11718–381. Las Vegas, NV.
U.S. Department of Energy, Nevada Operations Office. 2000c. Completion Report forWell-ER-EC-4. DOE/NV/11718–397. Las Vegas, NV.
Wahl, R. R., D. A. Sawyer, M. D. Carr, S. A. Minor, J. C. Cole, WC Swadley, R. J. Laczniak,R. G. Warren, K. S. Green, and C. M. Engle. 1997. Digital Geologic Map of the Nevada TestSite Area, Nevada. U.S. Geological Survey Open-File Report 97-140, scale, 1:120,000. Denver, CO.
Warren, R. G. 2000. Written communications to Lance Prothro, Bechtel Nevada, Las Vegas, NV,dated March 3, 2000, September 18, 2000, March 12, 2001, and March 13, 2001. Subject:Results of analyses on samples from Well ER-EC-2A.
Appendix A
Drilling Data
A-1 Drilling Parameter Logs for Well ER-EC-2AA-2 Casing Data for Well ER-EC-2AA-3 Well ER-EC-2A Drilling Fluids and Cement Composition
Appendix A-1
Drilling Parameter Logs for Well ER-EC-2A
A-1-1
A-1-2
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Appendix A-2
Casing Data for Well ER-EC-2A
A-2-1
Table A-2Casing Data for Well ER-EC-2A
CasingDepth Interval
meters (feet)
Type Grade
OutsideDiameter
centimeters(inches)
InsideDiameter
centimeters (inches)
WallThicknesscentimeters
(inches)
Weightper foot(pounds)
ConductorCasing
0 to 19.8(0 to 65.0)
Carbon SteelPE Weld
N/A76.2(30)
74.295(29.250)
0.953(0.375)
118.65
Surface Casing0 to 412.9
(0 to 1,354.6)CarbonSteel
K5533.97
(13.375)32.042
(12.615)0.965
(0.380)54.5
CompletionCasing
(with cross-over)
0 to 416.5(0 to 1,366.4)
Carbon Steelwith internal
epoxy coatingN80
19.37(7.625)
17.701(6.969)
0.833(0.328)
26.4
CompletionCasing
416.5 to 1,512.0(1,366.4 to 4,960.5)
StainlessSteel
SSTP30414.13
(5.563)12.819(5.047)
0.655(0.258)
14.6
A-2-2
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Appendix A-3
Well ER-EC-2A Drilling Fluids and Cement Composition
A-3-1
Table A-3-1Well ER-EC-2A Drilling Fluids
Typic al Air-Fo am M ix a
Typic al Air-Fo am/P olym er Mix a
11.4 liters (3 gallons) Geofoam ® b
per
7,949 liters (50 barrels) water
15.1 to 41.6 liters (4 - 11 gallons) Geofoam ®
and
3.8 to 15.1 liters (1 - 4 gallons) LP701 ® b
per
7,949 liters (50 barrels) water
a An air-foam (“soap”) mix was used as the drilling fluid in Well ER-EC-2A. No additives wereused between the depths of approximately 18.3 and 38.4 meters (60 to 126 feet). Variousproportions of polymer were added to the air-foam to suit conditions during drilling belowapproximately 38.4 meters (126 feet).
b Geofoam® foaming agent and LP701® polymer additive are products of Geo Drilling Fluids, Inc.
NOTES:1. All water used to mix drilling fluids for Well ER-EC-2A came from the Coffer Dune Well.2. A concentrated solution of lithium bromide was added to all introduced fluids to make up a final
concentration of 0.7 to 173 milligrams per liter.
Table A-3-2Well ER-EC-2A Cement Composition
Cement
Composition
30-in.a
Conductor Casing
13d-in. Surface
CasingCompletion
Type II plus2 percent CaCl
4.6 to 20.1 m b
(15 to 65 ft c)Not used Not used
Type II neat0 to 4.6 m (0 to 15 ft)
0 to 20.4 m(0 to 67 ft)
228.6 to 418.2 m(750 d to 1,372 ft)
210.9 to 498.3 m(692 to 1,635 ft)
681.5 to 788.5 m(2,236 to 2,587 ft)
832.1 to 922.0 m(2,730 to 3,025 ft)
1,098.2 to 1,344.2 m(3,603 to 4,410 ft)
a inch b meter(s) c foot (feet) d estimated
A-3-2
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Appendix B
Well ER-EC-2A Fluid Management Data
B-2
Preliminary Analytical Results for Fluid Management Samples from Well ER-EC-2A
SampleNumber
Date &Time
CollectedComment
Resource Conservation Recovery Act Metals (mg/L) a GrossAlpha
(pCi/L) b
GrossBeta
(pCi/L)Tritium(pCi/L)Arsenic Barium Cadmium Chromiu
mLead Selenium Silver Mercury
EC-2A-01250-1 01/25/200012:35
Sampletaken fromunlined Sump#1
Total 0.013 0.036(B) c
0.00027(U) d
0.012 0.039(J) e
0.0066 0.01(U)
0.00011(UJ) f
Dissolved 0.0096(B)
0.002(B)
0.00018(U)
0.004(B)
0.003(UJ)
0.0042(B)
0.01(U)
0.0002(UJ)
12.2E g =4.7
15.3E=4.8
-200E=160
(U)
EC-2A-01250-2 01/25/200012:45
Duplicatesample taken from unlinedSump #1
Total 0.017 0.039(B)
0.005(U)
0.0013 0.045(J)
0.005(U)
0.01(U)
0.00015(UJ)
Dissolved 0.011 0.00078(B)
0.0005(U)
0.0036(B)
0.003(UJ)
0.005(U)
0.01(UJ)
0.00002(UJ)
12.3E=4.8
14.1E=4.7(U)
-190E=160
(U)
EC-2A-02140-1 02/14/200014:15
Sampletaken fromunlined Sump#2
Total 0.0068(J) 0.029(J)
0.005(UJ)
0.017(J)
0.003(UJ)
0.005(UJ)
0.01(UJ)
5.1e-05(J)
Dissolved 0.0061(J) 0.0064(J)
0.005(UJ)
0.017(J)
0.003(UJ)
0.0038(J)
0.01(UJ)
2.5e-05(J)
7.4E=30
12.0E=2.1
-50E=170
(U)
EC-2A-02140-2 02/14/200014:30
Sampletaken fromunlined Sump#1
Total 0.0096(J) 0.053(J)
0.005(UJ)
0.0047(J)
0.072(J)
0.005(UJ)
0.01(UJ)
9.5e-05(J)
Dissolved 0.0068(J) 0.0018(UJ)
0.005(UJ)
0.0036(J)
0.003(UJ)
0.005(UJ)
0.01(UJ)
5.5e-05(J)
11.0E=2.3
8.3E=6(U)
-90E=170
(U)
Contract-Required Detection Limit 0.01 0.1 0.005 0.01 0.003 0.005 0.01 0.0002 N/A h N/A N/A
Nevada Drinking Water Standard (NDWS) 0.05 2.0 0.005 0.1 0.015 0.05 0.1 0.002 15 50 20,000
5 Times NDWS 0.25 10 0.025 0.5 0.075 0.25 0.5 0.01 75 250 100,000
Data provided by IT (IT, 2000) All analyses by Paragon Analytics, Inc.
a mg/L = milligrams per literb pCi/L = picocuries per literc B = Result less than Contract-Required Detection Limit, but greater than the Instrument Detection Limitd U = Result less the Instrument Detection Limit or the Minimum Detectable Concentratione J = Estimated Valuef UJ = Estimated result less than the Instrument Detection Limit or the Minimum Detectable Concentrationg E = Errorh N/A = Not applicable
Appendix C
Preliminary Detailed Lithologic Log for Well ER-EC-2A
C-1
Preliminary Detailed Lithologic Log for Well ER-EC-2aLogged by H. M. Noto and L. B. Prothro (BN Geological and Hydrological Services)
October 2000
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
0 - 31.1
(0 - 102)
12.8
(42)DA 90
Pumiceous Lava: Yellowish gray (5Y 8/1) to light brownish gray
(5YR 6/1); mostly vitric, much less devitrified and silicic;
pumiceous and perlitic; rare felsic phenocrysts of plagioclase and
sanidine; rare to minor biotite and hornblende; conspicuous
sphene; chalcedony is present as loose fragments.
Tfbw
31.1 - 61 .0
(102 - 200)
29.9
(98)DA
Lava: Mottled light brownish gray (5YR 6/1), moderate greenish
yellow (10Y 7/4), a nd pa le bro wn (5 YR 5 /2); alt eratio n is va riable
and includes devitrified, silicic, vitric, and zeolitic, with zeolitization
decreasing towards ba se; spherulitic, including distinctive dark
reddish brown (10R 3/4) spherulites; perlitic where vitric; minor
felsic phenocrysts of feldspar; minor to common hornblende and
biotite; conspicuous sphene; chalcedony occurs as coatings,
cavity fillings, and loose fragments.
61.0 - 81 .7
(200 - 268)
20.7
(68)DA
Lava: Pale red (10R 6/2) and pale brown (5YR 5/2); devitrified,
silicic , and vitric, m uch less z eolitic ; wea kly to mod erate ly
spherulitic, including distinctive dark reddish brown (10R 3/4)
spherulites; perlitic where vitric; minor felsic phenocrysts of
feldspar, inc luding ch atoyan t sanidine; m inor to com mon b iotite
and lesser hornblende; cons picuous sphene; cha lcedony occurs
as coatings, cavity fillings, and loose fragments.
81.7 - 94 .5
(268 - 310)
12.8
(42)DA
Lava: Mottled pale yellowish brown (10YR 6/2), medium light gray
(N6), grayish red (10R 4/2), and light brownish gray (5Y R 6/1);
devitrified and silicic; flow-banded; weakly pumiceous in lower
part; rare to minor felsic phenocrysts of feldspar; minor biotite and
lesser hornblende; sphene an d pseudom orphs after sphene are
presen t.
Lithologic Log for Well ER-EC-2A - October 2000 Page 2 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-2
94.5 - 16 6.7
(310 - 547)
72.2
(237)DA
Lava: Light gray (N7) and mottled light brown (5YR 6/4) and
med ium lig ht gra y (N6); de vitrified , less er silic ic; pumice ous in
some intervals; flow -bande d throug hout; m inor felsic ph enocry sts
of feldspar; minor to common biotite, and lesser hornblende;
conspicuous sphene; botryoidal chalcedony occurs as coatings
and loose fragm ents ; sec ondary q uartz -cry stal aggre gate s fill
voids.
Tfbw
166.7 - 1 76.8
(547 - 580)
10.1
(33)DA
Lava: Mottled grayish red (10R 4/2) and moderate orange pink
(10R 7/4); devitrified and silicic; flow-banded; weakly spherulitic;
minor felsic phenocrysts of feldspar, including chatoyant sanidine
and partia lly alte red fe ldspar; m inor to com mon biotite ; sphene is
presen t.
176.8 - 1 93.5
(580 - 635)
16.8
(55)DA
Lava: Moderate brown (5YR 4/4) to moderate brow n (5YR 3/4),
pale yellowish brown (10YR 6/2), medium light gray (N6), and
lesser grayish black (N2); devitrified, silicic, and lesser vitric;
spherulitic, perlitic where vitric; minor felsic phenocrysts of
feldspar; minor biotite; conspicuous sphene; chalcedony occurs as
loose fragments; numerous hairline fractures filled with silica.
193.5 - 2 07.3
(635 - 680)
13.7
(45)DA 680
Vitrophyric Lava: Mostly grayish black (N2), lesser dusky
yellowish brown (10YR 2/2); mostly vitric, much less devitrified;
perlitic; minor felsic phenocrysts of sanidine and plagioclase; minor
biotite and lesser hornblende; conspicuous sphene.
207.3 - 2 27.4
(680 - 746)
20.1
(66)DA 750
Pumiceous Lava: Pale brown (5YR 5/2) and light brown (5YR
5/2); devit rified, p artially silicic; rem nan t perlitic textu re; m inor fe lsic
phenocrysts of sanidine and plagioclase; minor biotite and lesser
hornblende; conspicuous sphene and pseudomorphs after
sphene; rare to minor dusky brown (5YR 2/2) lithic fragments;
drusy quartz lines cavities.
Lithologic Log for Well ER-EC-2A - October 2000 Page 3 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-3
227.4 - 3 99.3
(746 - 1,310)
171.9
(564)DA
1,010
1,260
Nonw elded Tuff: Light b rown (5YR 6/4) a bove appr oxim ately
243.8 m (800 ft), moderate yellowish brown (10YR 5/4) and dusky
yellow (5Y 6/4) to approximately 317.0 m (1,040 ft), light brown
(5YR 6/4) to approximately 356.6 m (1,170 ft), grayish orange
(10YR 7/4) below ; zeolitic, partially silicic; com mon mod erate
yellowish brown (10YR 5/4) to light olive brown (5Y 5/6) pumice;
common felsic phenocrysts of sanidine and plagioclase, trace of
quartz; minor to common biotite and hornblende; conspicuous
sphene and pseudomorphs after sphene; common dark reddish
brown ( 10R 3 /4) and g rayish red p urple (5R P 4/2) lithic frag men ts
consisting of various volcanic lithologies; drusy quartz occurs as
coatings and cavity linings.
Tfbw
399.3 - 4 27.9
(1,310 - 1,404)
28.7
(94)DA 1,350
Nonw elded Tuff: Pale redd ish brow n (10R 5/4) to mo derate
reddish orange (10R 6/6); quartzo-feldspathic; common grayish
orange (10YR 7/4) to pale yellowish brown (10YR 6/2) pumice;
rare to minor felsic phenocrysts of sanidine and plagioclase, trace
of quartz ; rare biotite; ps eudom orphs a fter sphe ne are p resent;
rare to minor lithic fragments.
427.9 - 6 46.8
(1,404 - 2,122)
218.8
(718)DA
1,500
1,700
1,960
Nonw elded Tuff: Grayish orange (10YR 7/4), dusky yellow (5Y
6/4), and pale yellowish brown (10YR 6/2); quartzo-feldspathic;
comm on to abu ndant pu mice; m inor to com mon fe lsic phen ocrysts
of sanidine and plagioclase, some partially to strongly altered, and
much less quartz; minor to common black biotite; rare to common
lithic fragme nts with m ore lithic-rich inte rvals oc curring a t 448.1 to
457.2 m (1,470 to 1 ,500 ft) and 487.7 to 5 06.0 m (1,600 to
1,660 ft).
Ultrasonic borehole image log indicates fractures at the following
depths: 444.1; 485.9-488.9; 509.6; 512.1; 528.5; and 599.2 m
(1,457, 1,594-1,604, 1,672, 1,680, 1,734, and 1,966 ft). Most of
the fractures have dips greater than 70 degrees.
Lithologic Log for Well ER-EC-2A - October 2000 Page 4 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-4
646.8 - 6 66.0
(2,122 - 2,185)
19.2
(63)DA 2,190
Nonw elded Tuff: Moderate brown (5YR 4/4) to light brown (5YR
6/4); moderately quartzo-feldspathic, with significant silicification;
common dusky yellow (5Y 6/4) pumice; minor felsic phenocrysts of
sanidine and plagioclase, both partially altered, and much less
quartz; m inor to com mon biotite and le sse r horn blend e; min or lithic
fragments.
Tfbw
666.0 - 8 30.3
(2,185 - 2,724)
164.3
(539)DA
2,380
2,600
Nonw elded Tuff: Light brown (5YR 6/4) and grayish orange
(10YR 7/4) above approximately 719.3 m (2,360 ft), l ight brown
(5YR 6/4) to pale reddish brown (10R 5/4) from 719.3 to 768.1 m
(2,360 to 2,520 ft), becoming grayish pink (5R 8/2) below;
moderately to strongly quartzo-feldspathic, degree of alteration
incre asing with depth; comm on pu mice ; rare to comm on fe lsic
phenocrysts of altered feldspar, including kaolinite pseudomorphs
after plagioclase, and lesser quartz; common biotite; one
pseudomo rph after sphene observed at depth 716.3 m (2,350 ft);
rare lithic fragments.Tfb, undivided
830.3 - 8 58.0
(2,724 - 2,815)
27.7
(91)DA 2,780
Moderately W elded Ash-F low Tuff: Pale reddish brown (10R
5/4); moderately quartzo-feldspathic, with significant silicification
near top of unit; flow-like features observed may reflect
reomorphism; common pumice; common felsic phenocrysts of
unaltered to partly altered sanidine, lesser pseudomorphs after
plagioclase, and lesser quartz; common biotite; pseudomorphs
after sphene are present; minor to common lithic fragments.
Ultrasonic borehole image log indicates fractures above 842.8 m
(2,765 ft). Fractures appear to dip more than 80 degrees.
Lithologic Log for Well ER-EC-2A - October 2000 Page 5 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-5
858.0 - 8 67.5
(2,815 - 2,846)
9.4
(31)DA
Partially Welded As h-Flow Tu ff: Pale reddish brown (10R 5/4);
mode rately qua rtzo-felds pathic; co mmo n pum ice; mino r to
common felsic phenocrysts of feldspar, pseudomorphs after
feldspar, and much less quartz; minor partially altered biotite;
pseudomorphs after sphene are present; minor lithic fragments.
Ultrasonic borehole image log indicates two fractures dipping
approximately 70 degrees at 858.3 m (2,816 ft).Tfb, undivided
867.5 - 9 40.3
(2,846 - 3,085)
72.8
(239)DA
2,960
3,060
Nonw elded Tuff: Pale red (10R 6/2) and pale reddish brown
(10R 5 /4) at the top , becom ing pale red purple (5R P 6/2) to
medium light gray (N 6) lower; s trongly qu artzo-feld spathic, w ith
degree of alteration increasing towards base, weakly calcareous;
minor to common pumice; minor to common felsic phenocrysts of
pseud omorp hs after feld spar, an d muc h less qu artz; rare to
com mon biotite , with a bundance inc reas ing w ith depth; m inor lith ic
fragments.
940.3 - 9 46.1
(3,085 - 3,104)
5.8
(19)DA
Reworked Tuff and Tuffaceous Sandstone: Samples consist
mostly of grayish red (10R 4/2), light gray (N7), pinkish gray (5YR
8/1), gree nish gray (5G 6/1), a nd br own ish gr ay (5 YR 4 /1), ze olitic
to quartzo-feldspathic, and weakly calcareous, m edium- to very
fine-grained, laminated, well indurated, reworked tuff and
tuffaceous sandstone.
Samples also consist of in lesser abundance, loose pieces of
cha lcedony , and brow nish black (5YR 2/1), m oderately
calcareous, coarsely crystalline fragments of an unknown lithology
(probab ly high ly alte red w elded tuff w ith ca lcite, b ut possib ly
chemically deposited or diagenetically altered fine-grained
sedimentary rock).
Ultrasonic borehole image log shows a high degree of bedding
within this interval, with beds dipping approximately 20 degrees.
Tf, undivided
Lithologic Log for Well ER-EC-2A - October 2000 Page 6 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-6
946.1 - 9 61.6
(3,104 - 3,155)
15.5
(51)DA
3,130
3,150
Tuffaceous Siltstone/Rewo rked Ash, and lesser Welded T uff
and Tufface ous Sand stone/Rew orked Tuff: Samples consist
of:
Tuffaceous Siltstone/Reworked Ash: Mostly medium dark gray
(N4 ) to bla ck (N 1) to a ppro xima tely (3 ,140 ft), becom ing m ulti-
colored (e.g. pale yellowish brown (10YR 6/2), moderate pink (5R
7/4) to moderate reddish orange (10R 6/6), dark yellowish orange
(10Y R 6/6 ), etc. ) belo w 95 7.1 m (3,14 0 ft); m ass ive to very thinly
lamin ated . Man y inte rvals are s trong ly silicif ied, obscuring grain
size . Thin -sec tion a t 954 .0 m ( 3,13 0 ft) is d esc ribed as finely
laye red lig ht-co lored chalc edony an d dar k-co lored stron gly
silicified and carbonized clay. Two lithologies are described for the
thin-section at 960.1 m (3,150 ft): (1) strongly carbonized clay
with bands of analcime interpreted as hydrothermally altered
lacustrine sedime nts, (2) m edium g rained ag gregate s of calcite
with much lesser analcime and minor clay, interpreted as
chemically precipitated hydrothermal deposits. X-ray diffraction
analyses indicate samples at 954.0 and 960.1 m (3,130 and
3,150 ft) contain 3.8% and 5.5% fluorite, respectively.
Welded Tuff (occurs m ostly above 957.1 m [3,140 ft]): Grayish
black (N2), lesser greenish gray (5GY 6/1); strongly quartzo-
feldspathic and pyritic; abundant felsic phenocrysts of
pseudomorphs after feldspar; no visible biotite.
Samples also contain lesser amounts of reworked tuff (same as
the reworked tuff described for the overlying interval).
Ultrasonic borehole image log shows a high degree of bedding
through out interva l, with beds dipping ap proxim ately 20 d egrees .
Log also indicates the presence of two generally parallel fractures
dipping approximately 75 degrees at 950.7 m (3,119 ft) depth.
Tf, undivided
Lithologic Log for Well ER-EC-2A - October 2000 Page 7 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-7
961.6 - 9 68.7
(3,155 - 3,178)
7.0
(23)DA 3,170
Nonw elded Tuff: Medium gray (N5) to approximately 966.2 m
(3,170 ft) becoming partly moderate reddish orange (10R 6/6)
below ; qua rtzo- felds path ic, py ritic; co mm on to abun dan t felsic
phenocrysts of pseudomorphs after feldspar, and conspicuous
quartz; rare to common biotite; a pseudomorph probably after
sphene observed in thin section; rare to common lithic fragments.
Tm, undivided
968.7 - 9 76.6
(3,178 - 3,204)
7.9
(26)DA
Nonw elded Tuff: Dark y ellowish b rown (1 0YR 4 /2) and m oderate
reddish brown (10R 4/6); quartzo-feldspathic with significant
silicification; common to abundant felsic phenocrysts of feldspar
and conspicuous quartz; rare biotite.
976.6 - 9 79.0
(3,204 - 3,212)
2.4
(8)DA 3,210
Nonw elded Tuff: Moderate reddish orange (10R 6/6) to light
brown (5YR 6 /4); quartz o-feldspa thic; com mon fe lsic phen ocrysts
of pseudomorphs after feldspar and lesser quartz; rare altered
biotite ; a pseudomo rph p roba bly af ter sp hene obs erve d in thin
section; rare lithic fragments.
979.0 - 9 97.3
(3,212 - 3,272)
18.3
(60)DA
Nonw elded Tuff: Very pale orange (10YR 8/2) and medium light
gray (N6) to brownish gray (5YR 4/1); strongly quartzo-feldspathic,
sign ifican tly silic ic in so me in terva ls; min or to c omm on fe lsic
phenocrysts of pseudomorphs after feldspar, and conspicuous
quartz; minor, generally altered, biotite; rare lithic fragments.
997.3 - 1 ,181.1
(3,272 - 3,875)
183.8
(603)DA
3,310
3,510
3,720
3,850
Nonw elded Tuff: Light olive gray (5Y 5/2), very pale orange
(10YR 8/2), yellow ish gray (5Y 8/1), a nd very light gray (N 8) to
med ium d ark g ray (N4) ; stron gly qu artzo -felds path ic, we akly
pyritic; weakly spherulitic; rare to minor pumice; rare to common
felsic phenocrysts of quartz, pseudomorphs after feldspar, and
secon dary felds par repla ceme nts; rare to minor bio tite; minor to
common lithic fragments.
Thin sec tion analyses sugg est m uch of inte rval m ay be mod erate ly
welded tuff.
Lithologic Log for Well ER-EC-2A - October 2000 Page 8 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-8
1,181.1 - 1,211.9
(3,875 - 3,976)
30.8
(101)DA
Nonw elded Tuff: Medium dark gray (N4); strongly quartzo-
felds path ic; we akly s phe rulitic; c om mo n to abundan t felsic
phenocrysts of conspicuous quartz, and pseudomorphs after
feldspar; minor biotite; rare lithic fragments.
Tm, undivided
1,211.9 - 1,400.3
(3,976 - 4,594)
188.4
(618)DA
4,080
4,280
4,450
Nonw elded Tuff: Very light gray (N8) to medium gray (N 5),
yellowish gray (5Y 8/1), and light brownish gray (5YR 6/1);
strongly quartzo-feldspathic, pyritic, and very weakly calcareous;
minor to common pumice; minor to common felsic phenocrysts of
pseudomorphs after feldspar and lesser, yet conspicuous, quartz,
including dipyramidal quartz; rare to minor biotite; rare to common
lithic fragments.
Thin section analyses suggest that the upper and lower portions of
interval m ay be m oderate ly welded tuff.
1,400.3 - 1,410.0
(4,594 - 4,626)
9.8
(32)DA 4,610
Moderately W elded Ash-F low Tuff: Medium dark gra y (N4) to
dark gray (N3) ; qua rtzo- felds path ic; min or pu mice ; abundant fels ic
phenocrysts are pseudomorphs after feldspar and lesser quartz;
common biotite; minor lithic fragments.
1,410.0 - 1,452.1
(4,626 - 4,764)
42.1
(138)DA 4,690
Nonw elded Tuff: Yellowish gray (5Y 8/1) and light brownish gray
(5YR 6/1); strongly quartzo-feldspathic, weakly calcareous; minor
to common pumice; comm on to abundant felsic phenocrysts are
pseudomorphs after feldspar and lesser quartz; minor to common
mostly altered biotite; minor lithic fragments.
Lithologic Log for Well ER-EC-2A - October 2000 Page 9 of 10
Depth
Interval
mete rs (feet)
Thickness
meters
(feet)
Sam ple
Type a
Labora tory
Analyses b Lithologic Description
c Stratigra phic
Unit d
C-9
1,452.1 - 1,516.1
(4,764 - 4,974)
TD
64.0
(210)DA, SC
4,830
4,974
Moderately W elded Ash-F low Tuff: Dark gray (N3) to grayish
black (N2); quartzo-feldspathic, weakly calcareous and chloritic;
common pumice; abundant felsic phenocrysts are pseudomorphs
after feldspar, a nd les ser q uartz ; com mon to abundant m afic
minerals are mostly unaltered biotite, and lesser pseudomorphs
after clinopyroxene and sphene; minor li thic fragments. No
mon azite (cha racte ristic o f the R ainier Mes a Tu ff) obs erve d in thin
section or indicated by neutron activation analysis.
Tmar
a DA = drill cuttings tha t represe nt lithologic ch aracter o f interval; SC = sidewall core.
b Notation s refer to a nalyses c onduc ted on the sam ple depth s indicated . See T able 3-2 o f this repor t for additiona l informa tion.
c Descriptions are based mainly on visual examination of lithologic samples using a 10x- to 40x-zoom binocular microscope and geophysical
logs. Additional data from laboratory analyses have been incorporated into the descriptions. Colors describe we t sample color.
Abund ances for felsic ph enocrys ts, pum ice fragm ents, and lithic fragm ents: trace = only one o r two individu als obse rved; rare = < 1%;
minor = 5%; common = 10% ; abundant = 15% ; very abundant = > 20%.
Abund ances for ma fic mine rals: trace = only one o r two individu als obse rved; rare = < 0.05% ; minor = 0.2% ; common = 0.5% ;
abundant = 1%; very abund ant = > 2%.
d Tfbw = rhyolite of Be atty W ash; Tfb = Beatty W ash Fo rma tion; Tf = Volcan ics of Fo rtymile Ca nyon; Tm = Tim ber Mo untain G roup;
Tmar = ma fic-rich Am mon ia Tank s Tuff .
C-10
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Appendix D
Geophysical Logs Run in Well ER-EC-2A
D-1
Appendix D contains unprocessed data presentations of selected geophysical logs run inWell ER-EC-2A. Table D-1 summarizes the logs presented. See Table 3-3 for moreinformation.
Table D-1Well ER-EC-2A Geophysical Logs Presented
Log TypeRun
NumberDate
Log Interval
meters feet
Epithermal NeutronENP-1
ENP-2
01/27/2000
02/08/2000
19.8 - 409.7
396.2 - 1 ,510.3
65 - 1,344
1,300 - 4,955
Dens ityCDL-1
CDL-2
01/27/2000
02/08/2000
19.8 - 409.7
396.2 - 1 ,510.3
65 - 1,344
1,300 - 4,955
Array Induction and Dual Laterolog
(resistivity)
IND-1
DLL-1
01/27/2000
02/08/2000
19.8 - 41 2.7
396.2 - 1 ,510.3
65 - 1,354
1,300 - 4,955
Spontaneous PotentialSP-1
SP-3
01/27/2000
02/08/2000
19.8 - 41 2.7
396.2 - 1 ,510.3
65 - 1,354
1,300 - 4,955
Gamma RayGR-1
GR-2
01/27/2000
02/07/2000
19.8 - 41 2.7
393.2 - 1 ,515.8
65 - 1,354
1,290 - 4,973
Digita l Array Sonic
(delta T and sonic porosity)AC-1 02/08/2000 335.3 - 1 ,511.8 1,100 - 4,960
Spectral Gamma Ray
(potassium, thorium, uranium)
SGR-1
SGR-2
01/27/2000
02/08/2000
0 - 414.8
371.9 - 1 ,504.5
0 - 1,361
1,220 - 4,936
Thermal Flow 1 02/09/2000 502.9 - 1 ,082.0 1,650 - 3,550
Chemistry
(temperature, pH,
electrical conductivity)
1 02/09/2000 257.3 - 1 ,515.8 844 - 4,973
D-2
D-3
D-4
D-5
D-6
Distribution List
Copies
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Distribution List (continued)
Copies
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