SPE 122189

Improving Water Injectivity in Barrancas Mature Field with Produced Water Reinjection: A team Approach A.N.Cavallaro, SPE, YPF SA., M. Sitta, I. Torre, G. Palma, YPF S.A. E.Lanza, Universidad Nacional de Cuyo

Copyright 2009, Society of Petroleum Engineers This paper was prepared for presentation at the 2009 SPE European Formation Damage Conference held in Scheveningen, The Netherlands, 27–29 May 2009. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.

Abstract Produced water reinjection (PWRI) is one of the most usual ways of produced water reuse in mature fields with high water cut. The relationship between water quality and injectivity decline in wells is well known and it is particularly important in mature fields, such as Barrancas, an old field located in Mendoza –Argentina, with more than 40 years of water injection. In this reservoir significant injectivity losses were recorded when fresh water was replaced by produced water in the 90´s. Formation Damage mechanism is mainly caused by external cake. Particles are principally, iron sulfide, calcium carbonate, and oil droplets. Water treatment and injection well chemical stimulation are two important contributions to oil lifting cost at Barrancas. The average water quality is quite good between water treatment plant and wells. In spite of this, injection wells require regular acidic and non acidic stimulations to restore injectivity. To identify the causes, a team effort combining field experience, chemical and bacteriological analysis, laboratory and on site core flooding test was performed. Through this work, water quality performance between plant and down hole well at the level of perforated zones was analyzed. Oil and solids chemical dispersants were tested during core experiments to avoid fall of injectiviy. The experimental study has demonstrated that the use of dispersants could help to maintain water quality stability at the level of case perforations. A pilot in a selected group of wells will be implemented. It is likely to be successful. Down -hole water quality is a critical parameter as well as the on site evaluation tests. Based on the outcome new experiences and down-hole monitoring tool will be developed. The final goal is to improve water quality stability at the level of formation, prevent injectivity decline and reduce working pressure. Introduction The injection of produced water (PWRI) is the main process implemented in YPF SA to recover oil in Argentina. This is one of the most important reasons for high volumes of water produced. This is particularly true when water cut increases with the field maturity. The PWRI is an attractive option for improving oil recovery, and also to maintain pressure. Another important aspect is that produced water (PW) is an important source of minimizing environmental risks associated with water discharges. 1 94705

Furthermore studies have shown that the injection of produced water induces formation damage by external and internal filter cake. These mechanisms cause loss of injectivity especially PWRI matrix. 2(Bennion) Injectivity decline is a complex phenomenon that depends on the quality of water, conditions of injection and reservoir properties. The water quality required will be mainly a function of permeability and pore throats size distribution. Layers of small thickness and low permeability require better water quality than the corresponding layers with high pemeability. The mechanism and extent of the blockage for a given period of time depends on the formation, type, concentration, composition, shape and size distribution of particles in suspension, in addition the flow rate and injection pressure.368977

2 SPE 122189

Deposition of particles –External cake formation The relation between particle size and pore thoroat size distribution, is a key factor in establishing the mechanism of deposition of particles that occur in porous media. With the retention of particles in the pore throats starts to form a temporary cake on the face of formation. When it process reaches a certain thickness, the filter cake permeability government the decline of injectivity profile. In this step, the cake porosity and permeability are sensitive to the pressure applied. 5 IAPG

Factors affecting water quality There are many factors affecting the Injectivity. This category includes: - Suspended Solids. - Corrosion products. - Formation of precipitates inorganic / organic - Bacterial activity. - Content of oil. -H2S-souring 4 53987

The H2S generation increases the corrosion rate. The FeS produced has a very reduce water solubility. It is: 0.00062 g / 100 cm3. It can be deposited as scale on surface pipe surface facilities and injector well installation. Also the FeS suspension is transported by water, causing plugging. The oil in water agglomerates iron sulfide particles increasing plugging tendency. Barrancas, a mature oil field in Cuyana Basin, located in Mendoza province-Argentina (Figure. 1), injectivity losses. That provides an example of injectivity losses related to a PWRI system . 569533. This is an field that has been producing for over 60 years mostly parafinic oil (25 °API). The hydrocarbon accumulations come from sandstones of the Barrancas Formation at 2500 meters of depth. Water flooding started in 1967 and during decades only fresh water was injected, but in the 90’s fresh water was gradually replaced by production water (PWRI) with h igh ave rage o f salinity (Table 1) .It is a quite hot reservoir ( originally 100 °C and 85°C after waterflooding). Along with the change to salt water (PWRI) began to increase the injection pressure to 20,000 kPa. Associated to waterflooding project w i t h PWRI appears the H2S biological souring (H2S up 200 ppmv) and the plugging tendency of the injection water. When back flush samples were taken, these results have shown that iron sulfide species such as: pyrite, marcasite and mackinawite are present. Lower proportion of calcium carbonate scale and oil has been found with iron sulfide particles in some injection wells. The analysis of the composition of solids by XRD (X-Ray Diffraction) and chemical analysis is shown in Figure 2. Solids samples have been taken at different times, all of these shown that the most important solid present is iron sulfide. (See Table 2; 3). Table 3 are samples taken during 2008. It requires frequent treatments acid (HCl 10% or 10% HCl + 2% HF) and chlorine oxides formulations to remove the formation damage, restore the injectivity and reduce wellhead pressure. In some cases stimulation frequency is less than two months. A typical injectivity decline curve is show in Figure 3.About 100 or more chemical treatments are performed annually. The negative results of this situation on economics are: sweep efficiency is reduced and oil production decline. The water treatment cost, work overs, acidic and non acidic stimulations, facilities failures are increased .The high injection pressure produces high energy consumption. As a consequence the lifting costs on the field also increases and lost of revenue occurs. A work plan including differents actions has been implemented, beside it the poor injectivity continue in this reservoir with permeability range between 60- 100 mD. Water quality evolution vs depth has been included in the work plan. In this paper, a comprehensive laboratory and field tests studies were carried out at Barrancas field to identify and minimize the causes de rapid injectivity decline encountered in this mature waterflooding The current work analyzes specifically the water quality evolution down hole. This is the main difference with previous ones for Barrancas Field. Specific issues addressed included as a part of an integral water management program are: To examine and quantify the decline injectivity causes To identify an strategy for reducing working pressures

SPE 122189 3

To found the most cost effective solutions In the next section, previous related studies are summarized. In the section after that, the current procedures are described. Experimental results are presented and discussed in the last section. Diagnosis of Water Injectivity Decline Previous studies showed that the damage mechanism of particle deposition is mainly caused by formation of external cake during core fooding. Also in these experiments were conducted other tests such as pore throats and particle size and SEM Figures 4-a; 4-b show the particle deposition in porous media. The reservoir permeability varies between 60 and 250 mD for the cores tested. The average is estimated at 100 mD. The behavior of the stimulation was with the progress of pressure treatment validates laboratory experiences. Figure 5 shows a typical behavior between chemical treatments. The injectivity decline model (half life time) assuming external cake conclude that the time for injectivity decline between stimulations is similar to evolution observed in the field. It has been shown to integrate all the information that the cause of loss of injectivity is formation damage by external cake. Water injection declines during the formation of external cake. In addition to looking for a new stimulation system more effective and less expensive than the acid treatment for removing iron sulfide, a program to improve the water quality to the plant output has been implemented. The results are shown in Figure 6. Operational improvements have been observed between 2007 and 2008 year in all cases analyzed, which resulted in fewer events per year.(See Figure 7). Monitoring water quality at the well head, also indicates that there was decrease of TSS but despite the improvements continued decline of injectivity. From the field observations, it was acknowledged that a program of bacterial control with biocides was carried out. At the same time a plan has started to minimize operational problems to found the most effective solutions. In spite of the efforts, the injection wells need to be stimulated to restore injectivity. The multidisciplinary team presumes that the water quality is deteriorated with depth of the well causing the particles deposition and the reduced injection. As a first step the team has decided to understand the behavior of water quality down hole. The next section provides and approach that were followed to identifying and minimize the problems detected during decline injectivity due to solid depositions and plugging. Laboratory and Field Testing Programme To achieve the objectives, the following experimental work was conducted to determine: - Identify TSS variations, particle size distribution, SRB vs depth (between well head and perforations). - Perform Solid characterization - Study Chemical dispersant effect - Improve water quality stability - Reduce pressure injection - Collect information to: - Design a trial to verify laboratory tests results - Develop a down- hole monitoring tool porting a porous media (core) The tool porting is to identify differences in water quality between well head and well down at the level of perforations. This tool would be applied to follow the improvements during chemical treatments. The tests were based on: -Physical and chemicals analyses: to know water chemistry, water quality, particles size, solids composition, membrane filtration in the field and during core flooding tests. -Pore throats size distribution: -Petrophysics -SRB bacteria accounts (Sulfate reducing bacteria) -Formation damage core flooding test: to examine the injectivity performance, the chemical dispersant effect, the permeability and pressure profile. Core samples were selected of representative layers from Barancas Formation (CRI). The reservoir permeability and porosity

4 SPE 122189

of the selected cores are shown in Table 4 The pore throats size distribution are represented in Figure 8 Experimental Core Flooding Procedures A general core flooding procedure was followed for on site field tests and laboratory for all tests. These were designed to monitor permeability changes, pressure profile, flow rate profile, under certain pressure and temperature reservoir conditions. The variations can be attributed to mechanisms as solids deposition or in the case were chemicals are added the variation can be pressure stable or reduced. The steps are: - Saturate core with filtered formation water - Measure reference permeability simulating injection flow direction (filtered formation water) -Flow PWRI -Flow PWRI with chemicals All flow tests were performed at the Core test laboratory, LECOR, of the Universidad Nacional de Cuyo, Mendoza, Argentina. The core flooding equipment is schematically shown in Figure 9.During the chemical injection a pump for dosage was included. Up to now four core flooding test were carried on: one on site close injection well and three in the laboratory Core Flood 1 On site, flow rate variation to examine water quality on site. The equipment was installed very close the injection well. See Figure 10 Core Flood 2, to run a base line for permeability evolution (Kf/ki), and pressure injection profile when PWRI was injected Core Flood 3, 4 were flooded with PWRI and two preselected chemical dispersants for prevention of Formation Damage and follow the pressure evolution. Chemical dispersant Information Both are non ionic surfactant soluble in water. The application is extended to fresh water, salt formation water / sea water. This treatment promotes solids dispersion, clean perforations, clean the pipes, hydrocarbon dispersion and low injection pressure.The dosage was recommend by the provider and tested in laboratory. Results Physical and chemical analyses are shown in Tables 5-a, 5-b; 5-c. This information includes the variation a along the water system between Water Plant and injection well B-208. The TSS no presents an important increase , the most important variation belongs for sulfides. The filtration tests are shown in Figures 11-a and 11-b. Both present similar slope. A monitoring was implemented in B-118 and others wells, solids and particle size distribution is presented in Figures. This information evidence how the water quality properties are altered from well head until well down. SRB, TSS increases and soluble sulfides are reduced. The biological activity increases total suspended solids. Soluble sulfides are converted in insoluble sulfides. The oil in water is under specification but in the solid samples the oil content it is not in ppm order, It is in % p/p order.The oil would be sticking to iron sulfides promoving an increase in particle size. These results are presented in Tables 6; 7 and figures 12-a ; 12-b. Applying the rule “1/3-1/7” the comparison between particle size and pore thoroats distribution indicates that a filter cake would be formed. Core 1-On site Field test: a significant volume of water was injected in this core . The permeability reduction was not severely along the time.(Figure 13).The visual observation have not shown an external filter cake.During this test the TSS measured was 6 mg/l.

SPE 122189 5

The permeability profile: Core 2 Base LineCore 3-PWRI + Chemical “A”Core 4-PWRI + Chemical “B” is presented in Figure 14.The TSS determined in PWRI for this coreflooding was 50 ppm.This TSS value represemts an example of down hole composition.The change observed in injectivity result indicates the dispersant effect when the chemicals are injected.The products are reducing agglomerated particles also avoid filter cake formation. In the Figure 15 the pressure evolution is shown. This graphic show how the increasing in injection pressure is attenuate. Summary of studies Results presented in the previous section have given evidence that the water quality is deteriorated during the travel between surface and down hole. The poor water quality is attributed to bacterial activity, iron sulfides. The relation oil/iron sulfides requires further studies as the formation damage mechanism (internal cake) when particles are dispersed by chemical “A” and “B”. This effect could not been evaluated during the core flooding 3 and 4. Field Trial A field trial was designed and implemented to prevent decline of Injectivity based on core flooding results (core tests 3 and 4). The product selected was chemical dispersant called “A”. At the moment to prepare this paper the pilot is starting.Tis Treatament combines PWRI and product “A.” A special monitoring plan was implemented to follow the product performance in the injectors. At the same time is in phase design is the dowhole tool sampler to port a porous media. Conclusions 1-In this study was demonstrated the poor water quality down hole. 2-The poor injectivity is produced by sulfides and bacterial activity when the PWRI travel from well head to perforated zone 3- Base on the core flooding test the chemical dispersants avoid an external filter cake deposition. 4-During the test the decline injectivity and injection pressure is stabilized when chemical dispersants are added to PWRI. 5-This study has created new opportunities for understanding, monitoring and controlling water quality down hole. 6-The treatment would be clean wellbore and pipes. It appears to promote injection pressure reduction and improve injectivity decline. Recomendations Nomenclature PWRI: produced water reinjected PW: produce water SEM: scanning electron microscopy XRD: X-Ray diffraction HCl: hydrochloric acid HF: hydrofluoric acid TSS: Total Suspended Solids SRB: Sulfate Reducing Bacteria Acknowledgments The authors wish to thank YPF S.A. for permission to publish this paper. Also they would like to acknowledge specially,

6 SPE 122189

Javier Sanagua, Director of Mendoza Norte business Unit. The authors are grateful to: Eduardo Curci, Santiago Bertagna, Raul Movio, Marcelo Escobar, Luis Farias, Dante Crosta, Juan Carlos Scolari from YPF S. A., for their valuable contribution and suggestions given during the study, also operative group that work in Barrancas Field. Universidad Nacional de Cuyo students for their contribution during field test. The students are Jonatan Medina, Carlos Ferlaza, Marcelo Mascialino, Lucas Vasallo and Marcelo Parlante. Other contributions as from Fernando Gomez –Induser Group, Jorge Costanzo-ITBA, Fabian Sein CTA-YPF SA Technology Center are acknowledged. References

Cavallaro A., Curci E., Galliano G., Vicente M., Crosta D.,

SPE 122189 7

Leanza H., 2001, Design of an Acid Stimulation System with Chlorine Dioxide for the Treatment of Water-Injection Wells. SPE-Latin American and Caribbean Petroleum Engineering Conference. Buenos Aires. 2001. SPE-69533.

Curci E., Cavallaro A., Galliano G., Gerrard P., 2000, Sulfur compounds in injection Waters, oild and gas: origing, measurement and importance, Compuestos de Azufre en Crudos, Aguas y Gases: Origen , Medidición e Importancia, Congreso de Producción Proction Congresss, IAPG. Iguazu-Argentina.

Bennion, D.B.2001, An overview of formation Damage Mechanisms causing a reduction in the productivity and injectivity of oil and gas producing formations.Canadian International Petroleum Conference,Calgary, Alberta, Canada Collins, IR et al, 2004,Laboratory and Economic Evaluation of the Impact of Chemical Incompatibilities in Comingled Fluids on the Efficiency of a Produced Water Reinjection System: A North Sea Example,SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Lousiana, USA, February 2004 c Bennion, D.B. et al, Injection Water quality a key Factor to successful water flooding, Journal of Canadian Petroleum Technology, Volume 37, No.6, June 1998. F.A.H. Al-Abduwani et al, 2001, Visual Observation of Produced Water Re-Injection Under Laboratory Conditions. SPE European Formation Damage Conference, The Haghe, The Netherlands, May 2001-SPE 68977

8 SPE 122189

Value Barrancas (typical)

Barrancas (peaks)

pH 6.8 CO3-2 (mg/l) < 1 HCO3- (mg/l) 400 Cl- (mg/l) 30,000 SO4+2 (mg/l) 1,300 Ca+2 (mg/l) 1,220 Sr+2 (mg/l) 45 Ba+2 (mg/lt) <1 Mg+2 (mg/l) 60 T.S.S. (mg/l) 2.5 10 HC (mg/l) <1 4

Table 1: Average Physicochemical PWRI composition-Barrancas field

Parameter

B-297

B-488

FeS (% p/p) 21.1 55.7

Extracted in

Dichloromethane (% p/p)

0.40 1.25

Table 2: Solid samples taken in injection well installation (tubing and valves)

Parameter

B-487 S1 A

B-487 S1B

B-487 S2 SA

B-487 S2 SB

B-487 S 3

FeS (% p/p)

17.3 48.8 57.9 35.0 50.4

Extracted in

Dichloromethane (% p/p)

2.40 0.54 1.57 0.76 1.84

Table 3: Solid samples taken in injection well installation during 2008

Core Well B-342 Porosity (%) Permeability (mD)

1-3-1 16.0 89.41-6-4 14.1 204.92-7-2 16.3 103.72-6-4 14.1 113.64-8-2 22.8 80.8

Table 4: Porosity and Permeability values

SPE 122189 9

Parameter Value

pH 7Conductivity 103.3mS/cmTSS 2.3mg/lHidrocarbon < 0,1 mg/lTotal Sulfide 5.1 mg/lSolube Sulfide 4.6mg/l M.N. 4500 S-2 E -

Method

M.N. 4500 H-B M.N. 2510 – NACE TM-01-73Colorimetry Method – UV visibleM.N. 4500 S-2 E -

Parameter Value

pH 7Conductivity 105.3mS/cmTSS 2.8mg/lHidrocarbon < 0,1 mg/lTotal Sulfide 7.5 mg/lSolube Sulfide 5.7mg/l

Method

M.N. 4500 H-B M.N. 2510 – NACE TM-01-73Colorimetry Method – UV visibleM.N. 4500 S-2 E - M.N. 4500 S-2 E -

Table :5a Output BV Water Treatment Plant Table 5-b:Output b-87 Repumping Parameter Value

pH 7Conductivity 105,2 mS/cmTSS 4,5mg/lHidrocarbon < 0,1 mg/lTotal Sulfide 14,7mg/lSolube Sulfide 13,5mg/l M.N. 4500 S-2 E -

Method

M.N. 4500 H-B M.N. 2510 – NACE TM-01-73Colorimetry Method – UV visibleM.N. 4500 S-2 E -

Table 5-c: B-208 Well

Date:

Muestra FechaS.T.S. mg/l S-2(Total) mg/l S-2(Soluble) mg/l Fe mg/l

HC mg/l BSR Ph Cond.

B-355(1°Run Well head) 05-ago 2,8 25,2 19,8 1 0,1 … 7 102.7

B-355(2°Run-Well Head) 12-ago 4,2 12,4 12 1 0,1 < 1 6,8 103.8

B-487(Down Hole Sample) 20-ago 249 11,7 4,3 175 0,4 5 + 7,3 107.9

B-487(Well head) 20-ago 10,5 12,6 12 3 0,7 3+ 7,2 105.3

01-09-08

Monitoring: Wells: B-355 y B-487

Table 6: water quality vs depth

Datein situ sampleSamples: B-118 Well (Well head and down hole)

Sample DateTSS. mg/l

S-2(Total) mg/l S-2(Soluble) mg/l Fe mg/l

HC mg/l BSR Ph Conduct.

B-118 (Well head) 31-oct 4 12,6 11,5 1,1 0,3 2+ 6,9 102,2B-118 (down hole sample) 31-oct 84.1 23,1 4 253 0,5 4+ 7 102,7

10-11-08

Table 7. water quality vs depth in

10 SPE 122189

UGARTECHE

PAMPA PALAUCO

CERRO FORTUNOSO

ESTRUCTURA CRUZ DE PIEDRA

LUNLUNTA CARRIZAL

UGARTECHE

LOMA ALTA LOMA ALTA SUR

LOS CAVAOS

MALAL DEL MEDIO

RIO GRANDE

Cº DIVISADERO

LA BREAPTO. MUÑOZ

LOMA DE LOS ALTOSLOMA DE LA MINA

CERRO FORTUNOSO

PAMPA PALAUCO

BARRANCASBARRANCAS

UGARTECHE

PAMPA PALAUCO

CERRO FORTUNOSO

ESTRUCTURA CRUZ DE PIEDRA

LUNLUNTA CARRIZAL

UGARTECHE

LOMA ALTA LOMA ALTA SUR

LOS CAVAOS

MALAL DEL MEDIO

RIO GRANDE

Cº DIVISADERO

LA BREAPTO. MUÑOZ

LOMA DE LOS ALTOSLOMA DE LA MINA

CERRO FORTUNOSO

PAMPA PALAUCO

BARRANCASBARRANCAS

340

CUYANABASIN

MENDOZA

MENDOZA

10 KMVIZCACHERAS

RIO TUNUYAN

LA VENTANA

EL CARRIZAL DAM

30 Km

21 Km

17 Km

23 Km

BARRANCAS

Figure 1 : Field Location Figure 2: Weight composition of scale samples taken from different injections wells in 2000/2001. SPE 69533

Figure 3: Typical Injectivity decline curve in Barrancas Field

Weigh

t perce

nt (%)

Well number

Barrancas Field Injection Wells

SO4CaZnPbCO3CaFe2O3Si O2S Fe

 

INJECTOR WELL EJ2

0100200

26-

20-

14-

11- 5- 30-

25-

19-

14- 8- 2- 27-

22-

16-

11- 5-

DATE

Qi

( m3

/ d )

WORK OVER : 11/04/97 -STIMULATIONS: 04/30/98FIGURE 1: WELL INJECTIVITY DECLINEFigure 3:

SPE 122189 11

Figure : 4-a-SEM before PWRI flooding Figure. 4-b-SEM afterPWRI flooding  

3 05 0

1 051 22

1 381 3312 0

14 012 011 5

10 09 9 9 68 3 8 8 9 0

4 4 4 5 3 8 4220

10

50

12 0

35 6

1 902 00

1101 30

1 601 7017 017 217 819 520 020 020 52 0 02 0 52 0 52 002 082 102 10

2 001 942 00

0

60

3 0 2 00

50

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

4 0 0

02…18…

22…25…

29…01…

02…06…

12…16…

20…24…

26…03…

07…09…

17…21…

23…01…

05…13…

19…23…

02…

m3/día-kg/cm2

f ech a

S tim u la tion Beh avio r

C a u d al Pr e s ión

3 94

P re ssur e In ject i on

Fl ow  Ra te

St im ul at ion

Press ure   In je c t io n ‐ Flo w  Ra te  Ev o lut io n  v s  t ime

Figure 5:Injection Pressure and Flow rate profile between stimulations

0,00

20,00

40,00

60,00

80,00

100,00

120,00

E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208

Mg/

l

TSS-Total Suspended Solids

Year 2007 TSS

Year 2008 TSS

0,00

5,00

10,00

15,00

20,00

25,00

30,00

35,00

E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208

mg/

l

SULFIDES

Year 2007 SULFIDES

Year 2008 SULFIDES

  

12 SPE 122189

0,00

2,00

4,00

6,00

8,00

10,00

12,00

14,00

16,00

E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208

PP

MOIL CONTENT

Year 2007 HYDORCARBONS

Year 2008 HYDORCARBONS

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

4,00

4,50

E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208

Cal

do

sp

osi

tivo

s

SRB COUNTS

Year 2007 BACTERIA-SRB Counts

Year 2008 BACTERIA -SRB Counts

Figure 6: Water quality parameters followed during 2007 and 2008 year

0,63

0,92

0,49

2,58

3,67

2,49

3,21

4,60

2,97

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

4,00

4,50

5,00

2006 YEAR 2007 YEAR 2008 YEAR

EVEN

TS W

ELL

PER

YEAR

EVENTS WELL PER YEARBARRANCAS CRI Fm

Int. pozo año Estim.pozo año Eventos por pozo año Figure 7: Events per year

Figure 8: Pore throats distribution

SPE 122189 13

FLOW EQUIPMENT

Formation Water

Injection Water

Constant Rate Displacement Pump

Hydraulic Pump

Overburden Circuit

Triaxial Cell

Data acquisition system

Oven

Stirrer

Core

Back Flow Circuit

BackPressure

Effluent Collector

Figure 9. Core flooding euipment diagram

Figure 10: on site core flooding test

Figure 11a: figure 11-b:

14 SPE 122189

Figure 12- a Figure 12-b

0,00

0,50

1,00

1,50

0 1000 2000 3000 4000 5000 6000 7000 8000

Kf/K

i

PORAL VOLUM E INJECTED

FILTERED FORMATION WATER(Ki)

DECLINE INJECTIVITY -TEST 1ON SITE COREFLOODING

PERMEABILITIY PROFILE (Kf/Ki vs vp)Well Location B-355 - Yac. BARRANCAS - Core Nº 4 - 8 - 2( B-342)

PWRI

Figure 13: oni site core flooding test.

 

0,00

0,50

1,00

1,50

0 50 100 150 200

Kf/K

i

PORAL VOLUME INJECTED (PV)

FILTERED FORMATION WATER(Ki)

CORE FLOODING -TESTS :2; 3 AND 4

PEMEABILITY EVOLUTION (Kf/Ki vs PV)

WELL: B-342 - BARRANCAS FIELD- CORE Nº 1-3-1 -- 2-6-4 -- 2-7-2NOBP: 430 kg/cm2 - TEMPERATURE : 85 ºC

PWRI + PRODCUT A (250ppm)

PWRI + PRODUCT B (250ppm)

PWRI- BASE LINE

START PRODUCT INJECTION

Figure 14 : Permeability profile

 

0,01

0,10

1,00

10,00

0 50 100 150 200

PRES

SURE

(A

tm.)

Poral Volume Injected

CORE FLOODING -TESTS: 2; 3 AND 4PRESSURE EVOLUTION VS PORAL VOLUME INJECTED

Well: B-342 - Yac. BARRANCAS - CoreNº 1-3-1 -- 2-6-4 -- 2-7-2NOBP: 430 kg/cm2 -- Temperature: 85 ºC

PWRI + PRODCUT A(250ppm)

PWRI + PRODUCT B (250ppm)

PWRI -BASE LINESTART PRODUCT INJECTION

Figure 15: Pressure Profile