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.

1. 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. 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 i g h a v e r a g e 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

3. 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. 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.

5. 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. 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.,

7. 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. 8 SPE 122189
Value Barrancas Barrancas
(typical) (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
21.1 55.7
FeS (% p/p)
0.40 1.25
Extracted in
Dichloromethane (% p/p)
Table 2: Solid samples taken in injection well installation (tubing and valves)
B-487 B-487 B-487 B-487 B-487
Parameter S1 A S1B S2 SA S2 SB S3
17.3 48.8 57.9 35.0 50.4
FeS (% p/p)
2.40 0.54 1.57 0.76 1.84
Extracted in
Dichlorometh
ane (% p/p)
Table 3: Solid samples taken in injection well installation during 2008
Core Well B-342 Porosity (%) Permeability (mD)
1-3-1 16.0 89.4
1-6-4 14.1 204.9
2-7-2 16.3 103.7
2-6-4 14.1 113.6
4-8-2 22.8 80.8
Table 4: Porosity and Permeability values

9. SPE 122189 9
Parameter Value Method Parameter Value Method
pH 7 M.N. 4500 H-B pH 7 M.N. 4500 H-B
Conductivity 103.3mS/cm M.N. 2510 – Conductivity 105.3mS/cm M.N. 2510 –
TSS 2.3mg/l NACE TM-01-73 TSS 2.8mg/l NACE TM-01-73
Hidrocarbon < 0,1 mg/l Colorimetry Method – UV visible Hidrocarbon < 0,1 mg/l Colorimetry Method – UV visible
Total Sulfide 5.1 mg/l M.N. 4500 S-2 E - Total Sulfide 7.5 mg/l M.N. 4500 S-2 E -
Solube Sulfide 4.6mg/l M.N. 4500 S-2 E - Solube Sulfide 5.7mg/l M.N. 4500 S-2 E -
Table :5a Output BV Water Treatment Plant Table 5-b:Output b-87 Repumping
Parameter Value Method
pH 7 M.N. 4500 H-B
Conductivity 105,2 mS/cm M.N. 2510 –
TSS 4,5mg/l NACE TM-01-73
Hidrocarbon < 0,1 mg/l Colorimetry Method – UV visible
Total Sulfide 14,7mg/l M.N. 4500 S-2 E -
Solube Sulfide 13,5mg/l M.N. 4500 S-2 E -
Table 5-c: B-208 Well
Date: 01-09-08
Monitoring: Wells: B-355 y B-487
S.T.S. HC
-2 -2
Muestra Fecha mg/l S (Total) mg/l S (Soluble) mg/l Fe mg/l 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
Table 6: water quality vs depth
Date 10-11-08
in situ sample
Samples: B-118 Well (Well head and down hole)
-2
TSS. S (Total) HC
Sample Date mg/l mg/l S-2(Soluble) mg/l Fe mg/l mg/l BSR Ph Conduct.
B-118 (Well head) 31-oct 4 12,6 11,5 1,1 0,3 2+ 6,9 102,2
B-118 (down hole sample) 31-oct 84.1 23,1 4 253 0,5 4+ 7 102,7
Table 7. water quality vs depth in

10. 10 SPE 122189
ESTRUCTURA
CRUZ DE PIEDRA MENDOZA
BARRANCAS
BARRANCAS
LUNLUNTA CARRIZAL
30 Km
UGARTECHE
UGARTECHE
LOMA DE LOS ALTOS
21 Km
LOMA DE LA MINA RIO TUNUYAN
LA BREA
PTO. MUÑOZ
EL CARRIZAL DAM
LOMA ALTA 340
MENDOZA
LOMA ALTA SUR
PAMPA PALAUCO
PAMPA PALAUCO 17 Km
Cº DIVISADERO LA VENTANA
LOS CAVAOS
MALAL DEL MEDIO CUYANA
BASIN
RIO GRANDE 23 Km
CERRO FORTUNOSO
CERRO FORTUNOSO
VIZCACHERAS
10 KM
Figure 1 : Field Location
Barrancas Field Injection Wells
Weight percent (%)
SO4Ca
Zn
Pb
CO3Ca
Fe2O3
Si O2
Figure 2: Weight composition of scale samples taken from different injections wells in 2000/2001. SPE S Fe
69533
Well number
INJECTOR WELL EJ2
Qi ( m3 / d )
200
100
0
26-
20-
14-
11-
5-
30-
25-
19-
14-
8-
2-
27-
22-
16-
11-
5-
DATE
WORK OVER : 11/04/97 -STIMULATIONS: 04/30/98
Figure 3:
FIGURE 1: WELL INJECTIVITY DECLINE
Figure 3: Typical Injectivity decline curve in Barrancas Field

11. SPE 122189 11
Figure : 4-a-SEM before PWRI flooding Figure. 4-b-SEM afterPWRI flooding
400
S tim u la ti o n B e h a vi o r
350 35 6
P r e ss u r e In je c t io n ‐ Flo w Ra t e E v o lut io n v s t im e
300
2 250
m
c
P re s s u r e In j ec t i o n
/
g
k
- 3 94 2 08 2 102 10
a
í 200 2 00 19 5 20 020 0 20 52 0 02 0 52 0 52 00 2 00 1 94 2 00
d
/ 1 90
3 17 8
m 1 7017 0 17 2
1 60
150
14 0
1 30 1 38 1 33
1 22 12 0 12 011 5 12 0
110
1 05
100 10 09 9 9 6
83 88 90
Fl ow Ra te
60
50 50 4 4 4 5 3 8 42 50
30 30
St im u l at ion 20 20
10
0 0
0
2 1 2
8 2 2
5 2
9 0
1 0
2 0
6 1
2 1
6 2
0 2
4 2
6 0
3 0
7 0
9 1
7 2
1 2 0
3 1 0
5 1
3 1
9 2
3 0
2
… … … … … … … … … … … … … … … … … … … … … … … … …
C a u d al f ec h ae s ión
Pr
Figure 5:Injection Pressure and Flow rate profile between stimulations
TSS-Total Suspended Solids SULFIDES
35,00
120,00
Year 2007 TSS 30,00 Year 2007 SULFIDES
100,00
Year 2008 TSS
Year 2008 SULFIDES
25,00
80,00
20,00
mg/l
Mg/l
60,00
15,00
40,00
10,00
20,00
5,00
0,00 0,00
E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208 E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208

12. 12 SPE 122189
SRB COUNTS
OIL CONTENT
4,50
16,00
4,00
14,00
3,50
12,00
3,00
Year 2007 HYDORCARBONS
10,00
Caldos positivos
2,50
Year 2008 HYDORCARBONS
PPM
8,00
2,00
6,00
1,50
Year 2007 BACTERIA-SRB Counts
4,00
1,00
Year 2008 BACTERIA -SRB Counts
2,00 0,50
0,00 0,00
E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208 E.BBV S.BBV E.B87 S.B87 SAT.23 SAT.26 B-208
Figure 6: Water quality parameters followed during 2007 and 2008 year
EVENTS WELL PER YEAR
BARRANCAS CRI Fm
5,00
4,60
4,50
4,00
3,67
3,50
3,21
EVENTS WELL PER YEAR
2,97
3,00
2,58
2,49
2,50
2,00
1,50
1,00 0,92
0,63
0,49
0,50
0,00
2006 YEAR 2007 YEAR 2008 YEAR
Int. pozo año Estim.pozo año Eventos por pozo año
Figure 7: Events per year
Figure 8: Pore throats distribution

13. SPE 122189 13
FLOW EQUIPMENT
Hydraulic Pump
Overburden Circuit
Stirrer Data acquisition system
Formation Water
Oven
Injection
Water
Core
Triaxial Cell Back
Pressure
Effluent
Back Flow Circuit Collector
Constant Rate Displacement Pump
Figure 9. Core flooding euipment diagram
Figure 10: on site core flooding test
Figure 11a: figure 11-b:

14. 14 SPE 122189
Figure 12- a Figure 12-b
DECLINE INJECTIVITY -TEST 1
ON SITE COREFLOODING
PERMEABILITIY PROFILE (Kf/Ki vs vp)
Well Location B-355 - Yac. BARRANCAS - Core Nº 4 - 8 - 2( B-342)
1,50
FILTERED FORMATION WATER(Ki)
1,00
Kf/Ki
PWRI
0,50
0,00
0 1000 2000 3000 4000 5000 6000 7000 8000
PORAL VOLUM E INJECTED
Figure 13: oni site core flooding test.
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 -- 2-7-2
NOBP: 430 kg/cm2 - TEMPERATURE : 85 ºC
1,50
FILTERED FORMATION WATER(Ki)
PWRI + PRODUCT B (250ppm)
START PRODUCT INJECTION
1,00
Kf/Ki
PWRI + PRODCUT A (250ppm)
0,50
PWRI- BASE LINE
0,00
0 50 100 150 200
PORAL VOLUME INJECTED (PV)
Figure 14 : Permeability profile
CORE FLOODING -TESTS: 2; 3 AND 4
PRESSURE EVOLUTION VS PORAL VOLUME INJECTED
Well: B-342 - Yac. BARRANCAS - CoreNº 1-3-1 -- 2-6-4 -- 2-7-2
NOBP: 430 kg/cm2 -- Temperature: 85 ºC
10,00
START PRODUCT INJECTION PWRI -BASE LINE
1,00
PRESSURE (Atm.)
0,10 PWRI + PRODUCT B (250ppm)
PWRI + PRODCUT A(250ppm)
0,01
0 50 100 150 200
Poral Volume Injected
Figure 15: Pressure Profile