Copyright 2007, Society of Petroleum Engineers This paper was prepared for presentation at the 2007 SPE Latin American and Caribbean Petroleum Engineering Conference held in Buenos Aires, Argentina, 15–18 April 2007. 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, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes 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 where and by whom the paper was presented. Write Librarian, SPE, P.O. Box 833836, Richardson, Texas 75083-3836 U.S.A., fax 01-972-952-9435.

Abstract A water control approach integrating log interpretation, core analysis and production history has been designed and applied to extend life of the very mature heavy oilfields of Block 1AB, located in the Peruvian Jungle. The acquisition of new data, re-processing of old data, the use of new technologies, precisely complemented, by the innovation and experience of a multidisciplinary work team have been crucial towards refining selection of zones with high water production, and stablish a new completion scheme. It was proposed a methodology consisted of correlating neutron and production logs with core data to update the fluid saturation profile, in order to identify high water cut sands within Main Vivian and Vivian B formations. Also the technique is used to identify silt/shale beds with areal extension, separating Vivian A from B, and thin low permeability sands plugged with kaolinitc matrix within Main Vivian, which are interbedded with the productive sands; those layers are used as seal rocks when redesigning well completion. Eleven applications in Jibarito, Jibaro and Shiviyacu oilfields were developed during 2005-2006, with successful results. Oil production was instantaneously increased in 947 BOPD, while water production was sustainably reduced in 83647 BWPD. In addition, producing cost was reduced due to lowering energy consumption by means of a reduced pumping requirement, as well as, less water injection volume; diminishing surface water treatment and mitigated environmental impacts.

Introduction Field Overview

Block 1AB is located in the Northern part of Marañon foreland Basin (See Figure N°1). Occidental Oil Company found oil in Block 1AB on November 1972 with North Capahuari 1X, as the first well completed; then, confirmed the discovery with well South Capahuari 1X, on April 1973 and started production in 1974. Since then, more than 200 wells were drilled, allowing Block 1AB to achieve a peak oil rate of 140000 BOPD in 1979. Pluspetrol Norte S.A (PPN) began operating Block 1AB at the beginning of the year 2000, applying a new management strategy; An aggressive development plan was executed: 23 wells were drilled and 79 workovers were developed since the year 2000. Up to date, 85.3 MMBO have been produced by PPN. Currently 120 wells are being produced in 12 fields with an average production of 29,716 BOPD x 728,129 BWPD, with more than 96% of water cut. The cumulative oil production of Block 1AB was calculated in 665.0 MMBO by the end of year 2006. Water Production Management Recently, a new approach came into discusion when analyzing how to manage the high water cut of the Block 1AB’s oilfields. A flow chart was designed proposing a two-branch solution: • Water Control Techniques • Water Disposal.

Water Control Techniques In the latest years, most of the efforts of the Reservoir and Geology departments in PPN have been focused on evaluating alternatives to reduce water production. Therefore, it was necessary to organize a multidisciplinary team integrated by Reservoir Engineers, Geologysts and Production Engineers, who were in charge of studying the dynamics of fluid flow in the medium and heavy oil reservoirs, in order to identify what zones have been contributing with more water production, as

SPE 108039

Water Control in Heavy-Oil Mature Field, Block 1ABPedro Zegarra Sánchez, Marco Augusto Delgado, and Victor Huerta Quiñones, Pluspetrol Norte S.A.

2 SPE 108039

well as, how much oil has been trapped or bypassed in the other sands, with less productivity index. A new static and dynamic reservoir characterization was carried out following the next stages:

Geology Evaluation Block 1AB fields are located in the northern part of foreland Marañon basin, traps are mainly low relief elongated anticlines trending NW-SE with less than two degrees of structural dip; some traps have stratigraphic compound. The structures are located in a regional homocline, which is deepening to the southwest, and are distributed in four structural trends, which are related to pre-Cretaceous highs; those trends are named from West to East; Capahuari-Tambo, Ceci-Dorissa-Huayuri-Carmen, Jibarito-Jibaro-Shiviyacu Forestal and Tigre-Bartra-San Jacinto trends. Up to date, Fifteen commercial fields have been discovered and exploited in Block 1AB. The productive zones are located between 2220 and 3970 meters of vertical depth, with oil columns ranging between 7.5 and 39.0 meters. Most structures are filled to the spill point with under-saturated oil of variable gravity between 10.5 and 40° API. Productive reservoirs are composed of fluvial, estuarine and shallow marine sandstones from Basal Terciary, Vivian and Chonta Formations of Cretaceous age (See Figure N° 2). The Main productive reservoir is the Vivian Formation, which contains 85% of the production and the ultimate recoverable reserves of the area. The Vivian Formation is productive in all fields. It is composed of ortoquartzitic sandstones interbedded with thin silt/shale beds with poor lateral continuity. From base to top this Formation has been divided in three genetic units named; Lower Vivian, Main Vivian or Vivian “A” and Upper Vivian or Vivian “B”; they were deposited in different depositional environments (separated by silt/shale beds regionally distributed) and have different petrophisical properties. The lower Vivian sands conform the first depositional cycle of Vivian, they are not present in whole the area, they were deposited in an estuarine and fluvial environment, channels cut and fill a pre-existent low topography of the Chonta Formation. This unit has a variable thickness between 0 and 15 meters, the sandstones have fair to poor petrophysical quality with porosities between 10% and 18% and permeabilities between 1 to 500 millidarcys; in some areas this unit is silted out. Generally, this sand body is not bearing or non-reservoir. The Vivian “A” Sand or Main Vivian (Figure N° 3) is the most important unit of Vivian reservoir, it was deposited mainly in a braided stream fluvial environment, it is composed of clean and well sorted orthoquartzitic medium to coarse grained sandstones interbedded with some silt/shale beds which restrict the vertical flow of fluids within the reservoir avoiding partially an early water conning. The thickness of

this unit varies between 18.0 and 50.0 meters, the sands have excellent petrophysical characteristics, with porosities between 12 and 24% and permeability values between 50 and 5000 md. This unit contains more than 94% of the Vivian oil production and reserves. A thin shale bed with 1.0 to 4.0 meters of thickness seal and separate the Vivian “A” reservoir from the Upper Vivian “B” reservoir. The Vivian “B” Sands or Upper Vivian Sands (Figure 4) are underlaying the Vivian “A” Sand deposits. This unit is composed of low energy estuarine channels and marsh deposits; reservoir sand bodies are finning upwards coarse to very fine grain beds interbedded with thin silt/shale laminations. The sandstones have fair to good petrophysical properties, with porosities between 14.0 to 28% and permeabilities between 10 to 1000 millidarcys. The upper Vivian is present in whole the area with good reservoir quality in almost 30% of the Block 1AB; the thickness of this unit varies between 5.0 and 15.0 m. Combined structural/stratigraphic traps have been identified in this flow unit. The Cachiyacu Formation is overlying the Vivian Formation. It is composed of gray marine shales, with an average thickness of 13.0 m, which conform the seal rock of Vivian Reservoir. Traditionally, Vivian A had been characterized as a homogeneus reservoir (See figure N°5) . Now, a new model of Main Vivian has arised by cores and plugs analysis, integrated to a reinterpretation of gamma ray, resistivity and density curves, and assisted with production and saturation logs. According to the new theory, Vivian A would be composed of more than one flow unit (See Figure N° 6); very fine sands plugged with kaolinitic matrix acting as seal rocks have been identified within Main Vivian.

Reservoir Engineering Analysis All reservoirs are under-saturated Black Oil with very low GOR, 20-110 SCF/STB. The reservoir pressure is directly related to the structural position of the reservoirs in the basin, it varies from 3000 to 4400 psi in Vivian Fm, and 2200 to 3700 in Chonta Fm.. The main production mechanisms are bottom and edge water drive. Despite the existence of active water drive, the pressure of the system has dropped regionally approximately 500 psi; some lenticular reservoirs of Vivian “B” and Chonta Fm. produce by depletion gas drive. A wide range of oil gravities between 40.0° and 10.5° API are handled in the reservoirs of the area. The water cut of medium, and especially heavy oil reservoirs increase very fast to values above 90% in the early stages of exploitation, due to the differences in mobility between the viscous oil and the formation water. Heavy oil reservoirs, having low API gravities, high mobility ratio and fluid rate, shows an unsteable water front; thus, it results in a segregated flow pattern, know as underruning,

SPE 108039 3

when water breakthrough comes early, oil is inefficiencly displaced by water, and consequently, by passed. This phenomenon has recently been studied in more detail by using latest technology tools and software. Multidisciplinary team is been using The diagnose Chan’s type curves to let analyts differentiate between coning and lateral water entrance; in addition, production logging (PLT), is being run to identify the water and oil entry points, as well as, Saturation logs, to evaluate the producing zones and monitor the reservoirs, looking for new and bypassed productive zones. Finally, some numerical simulation studies have started to identify the remaining oil zones and clearly define the water entrances by coning, channelization and mechanic effects. With a better understanding of the fluid flow behaviour in medium and heavy oil reservoirs, the teams proceed to correlating production behaviour with reservoir rock characterization. An initial saturation profile was prepared by each well candidate, and compared, with the new one built up with the current data. The analysis shows us a rising of the original water oil contact (+- 5 meters), and also the presence of a more significant transition zone. Furthermore, it was discovered “by passed” oil, and eventually potential remanent reserves, in the upper Main Vivian, as well as, in Vivian B.

Production Engineering Analysis The use of ESP pumps in Block 1AB by the early 80´s allowed to increase the productivity and oil rate, extending the economic limit of the wells, and eventually, contributing with extending drainage area of the reservoirs, as well as, an increase of the ultimate recovery factor. However, water cut raised significantly up to figures higher than 96% in medium and heavy oil reservoirs. Before carrying out water shut off applications, pre-candidate wells required to run and record corrosion logs in order to identify casing damage and collapsed zones, and consequently take remedial actions. In addition, cementation logs (CBL-VDL) were used to verify hydraulical isolation between casing-cement, cement-formation. The evaluation of this information integrated to the Geology and Reservoir Analysis was very useful towards refining candidates selection, précising the water control application por each selected well, and finally, defining the new well completion & production scheme. Techniques and Field Case Review Three types of applications were proposed to isolate water zones within Vivian Formation, in medium and heavy oilfields (The productivity index greatly increases as water cut & saturarion raises due to high ratio mobilities): 1. Isolation with Bridge Plugs 2. Isolation with Selective Cement Plugs 3. Use of Relative Permeability Modifiers Case I: Isolation with Bridge Plugs This technique, consisting of setting a bridge plug between two zones, is applied, most of the times, when Main Vivian and Vivian B produce commingling; sometimes, it is feasible

to isolate water zones from oil zones within Vivian A.The following characteristics are required to succeed in isolation with bridge plugs:

o Enough areal extensión of the seal rock in order to have a sound separation between Main Vivian and Vivian B. (Cores and Logs Correlation)

o Big contrast of permeability (2500:500 md) o High Productivity Index Relationship (20:2 bpd/psi) o Almost original saturation distribution in Vivian B

and rising of the water oil contact in Main Vivian (RST interpretation). Poor productive behavoiur of Vivian B when producing conmingling with Main Vivian (PLT interpretation).

o Good hydraulical isolation between casing-cement, cement-formation (CBL-VDL evaluation)

It is worth pointing out that this application left important reserves in lower Vivian A sands, with high water cuts. This oil could be recovered, after draining most of the reserves in Vivian B and Upper Main Vivian, by reopening workovers History Case I: Jibarito 06 Well Well Analysis The interpretation of the Sigma & Carbon – Oxygen (C/O) Reservoir Saturation Log (RST), run while well was on production, from the top to the base (Figure N° 7), show us the following:

Open intervals from 2948.6 to 2946.2 mts. and from 2942.5 to 2939.2 mts. exhibit residual oil saturation.

There is a transition zone of 3.5 mts. (from 2926.0 to 2922.5 mts.) and the current level of the water – oil contact rised up to 2926.0 mts.

Upper Main Vivian (from 2922.5 to 2914.5 mts.) shows an almost original saturation profile

Vivian B keep a similar saturation profile as compared to original resistivity log interpretation

Recomendation According with RST evaluation, Vivian B and the top of Main Vivian show the same water saturation profile, similar to the original interpretation of resistivity logs. Therefore, it should first be recommended to isolate Main Vivian with a bridge plug, while producing Vivian B; then, as water cut raise 98%, cement the well and reopen selectively upper Main Vivian (Figure N° 8). Procedure • Pulled out ESP Assembly • Set Bridge Plug at 22913.8 mts to isolate Main

Vivian • Reperforated Vivian B from 2909.6 to 2912.7 mts. • Installed ESP Assembly Results: Before Job: 551 BOPD x 9473 BWPD x 96.5% WCUT After Job : 486 BOPD x 123 BWPD x 20.2% WCUT These results are shown in Figure N° 9

4 SPE 108039

In addition, six other jobs were carried out in Jibaro, Jibarito and Shiviyacu fields: Jibarito 01, 12, 7 and 8 along with Jibaro 03 and Shiviyacu 13. Oil production increased about 317 BOPD while water production diminished in 48190 BWPD (See Table N°1).

Caso II: Isolation with Selective Cement Plugs This technique has been applied when logs and core analysis indicated a presence of Vivian B with poor petrophysics characteristics. In this case, being Vivian A the only objective and mainly fully perforated, sound isolation could not be achieved with plugs and/or scab liners; it should be necessary to cement the whole package of Main Vivian, in order to establish the conditions to reopen selectively oil zones, disregarding high water saturation sands. It is worth pointing out, the precision towards recognizing very fine sands with kaolinitc matrix within Main Vivian, by correlating neutron and production logs with core data. The following characteristics are required to assure success when isolating with cement plugs:

o Identification of low permeability sands plugged with kaolinitc matrix, which are interbedded with productive sands within Vivian A, constraining vertical flow and reducing coning effects

o Wells with aggregated high productivity index (+ 20 bpd/psi)

o Recognition of new water - oil contacts withing Main Vivian, as well as, zones with almost original water saturation in the upper Vivian A. (RST Interpretation)

o Identification of higher water cut sands in the lower part of Vivian A, as well as, zones of poor production behavoiur on the top of Main Vivian (Evaluation of PSP log).

The application of this technique en Shiviyacu Field consisted of cementing the whole Vivian A, milling and cleaning cement up to some meters before the top of the seal-rock layer, and reperforate the top of main Vivian with deep penetration guns. Then, it was performed a well test with a jet pump to calculate the new productivity index. Finally, a new ESP Assembly was designed, run into hole, and the well reopened. History Case II: Shiviyacu 28 Well Well Analysis The interpretation of the Sigma & Carbon – Oxygen (C/O) Reservoir Saturation Log (RST), run while well Shiviyacu 28 was on production, from the top to the base (Figure N° 10), show us the following:

The zone open from 2890.0 to 2886.0 mts. shows residual oil saturation with almost 100% of water cut.

The current level of the water oil contact is situated at 2880.5 mts. within the perforated zone.

It has been identified a transition zone of 3 mts. until 2877.5 mts; Above this level up to the top of Main

Vivian (2878 mts.), saturation profile have not changed significantly as compared to original fluid distribution.

Vivian B, with reduced net thickness (2 mts.), keeps a similar saturation profile as compared to original resistivity log interpretation.

Recomendation According to RST and PSP evaluation (Figure N° 11) in Shiviyacu 28 Well, it was noted the existente of a seal layer at 2881.0 mts. restraining vertical flow within Main Vivian. Therefore, a balance cement plug was suggested to be pumped from bottom of Vivian A to 2878.5 mts. and reperforate upper Main Vivian from 2868.7 to 2877.3 mts. with deep penetration guns. Procedure • Pulled Out ESP Assembly • Run RST Log • Performed balanced cement plug in Vivian A • Clean cement up to 2878.5 mts. • Run DST to calcule the new productivity index in Upper

Main Vivian • Installed ESP Assembly Results Before Job: 250 BOPD x 11157 BWPD x 97.8% WCUT After Job : 363 BOPD x 32 BWPD x 8.1% WCUT These results are shown in Figure N°12 Additional jobs were carried out in other 3 wells: Shiviyacu 03, Shiviyacu 08 and Shiviyacu 10. The wholel oil production increased by 630 BOPD and the total reduction in water production was accounted for in 35500 BWPD (See Table N°2). Caso III: Relative Permeability Modifiers Chemical processes with Relative Permeability Modifiers are good alternatives to isolate swept zones in Main Vivian. Relative Permeability modifiers (RPM) are water-soluble, hydrophilic polymer systems that, when hydrated, produce long polymer chains loosely occupying the pore spaces. Being strongly hydrophilic, RPMs attract water and repel oil and, as a net result, they exert a drag force on water flow in the pores. The following list summarizes the conditions to apply this technique:

o There is no temperature limit in medium and heavy oilfields of Block 1AB (Reservoir Temperature 250°F)

o Good hydraulic isolation between casing-cement, cement-formation.

o Wells that we can produce commingled Main Vivian an Chonta, that we need to reduce the productivity index in Main Vivian

For the treatment, it was necessary to pump the RPM under matrix flow conditions, then to wait 24 hours, and finally to produce the well.

SPE 108039 5

History Case III: Jibaro 06 Well Well Analysis To evaluate the use of Relative Permeability Modifier in order to reduce water production in Main Vivian formation. The well had been producing 240 BOPD x 6510 BWPD x 96.4% WCUT x 10.5°API with a cumulative produccion of 3981.3 MBO and 45340.4 MBW by November 2006. The history Production is shown in (Figure N° 13) The log interpretation and the recomemended interval are shown in Figure N° 14. Procedure • Pulled Out BES Assembly • Mecanichal isolation of perforated intervals in the lower

Main Vivian with N-1 plug. • Tested lines with 3000 psi during 5 minutes • Pumped 100 bls of inhibited brine • Settled down 7” PKR to 3206.5 mts with 4 ½” tubing • Performed Injectivity Test with 30 bls. of inhibited brine

to different rates 0.5,1.0,1.5 barrel per minute • Pumped the following fluids in Main Vivian:

50 bls of solvent + MA 1 to clean organic deposits. 65 bls of SSA Organic 1.5% 70 bls of Inhibited Brine as a spacer 190 Bls of aquacon HP 6 %

• Displaced with 135 bls of WOF (max head Pressure: 1600 psi and Pumping Rate: 1 BPM)

• Shut off the well for 24 hours • Pull out of hole 4 ½” tubing with PKR; the fist 100 tubing

should be taken out slowly to avoid swab effect. • Run in Hole ESP Assembly • The pumping Operation chart is show in Figure N° 15. Results Before Job: 240 BOPD x 6510 BWPD x 96.5% WCUT After Job : 221 BOPD x 2663 BWPD x 92.0% WCUT The productivity index was reduced from 12.4 to 5 BPD/PSI Results are shown in Figure N° 16. Water Disposal It has been estimated that water control techniques will contribute with a reduction of 20 % of total water production, in Block 1AB. However, there are some limitations to extend these applications to all the oilfields, and consequently, there is a significant volume of water that PPN will have to reinject. Abandoned wells located at low structural position in the flanks of the fields are being used as injectors for water disposal, because in some fields, there are not available wet reservoirs above the producing zones to inject the water, and the disposal is being made within the productive reservoirs.

Currently, water disposal is executed in Jibarito and Dorissa Fields, accounting for 90000 and 50000 BWPD, respectively. There is a strong compromise of PPN to reinject all the water production of Block 1AB by the next years. Conclusions

The development and implementation of a Water Management Strategy, based on innovation, state of the art technology and a multidisciplinary approach, has lead Pluspetrol Norte to succeed in applying control techniques in Block 1AB, and eventually, will contribute with extending life of its mature oilfields. In 11 wells from Jibarito, Jibaro and Shiviyacu Oilfiedls, oil production was increased in 947 BOPD, while water production was reduced by 83647 BWPD.

Succesful results and availability of technology will

launch to extend applications to other wells and oilfields inside Block 1AB or even other neighbor areas, with similar reservoir characterization and dynamics.

Additionally, there is a significant impact when reducing

operative cost, by lowering surface water treatment and disposal, as well as, energy consumption.

Water control techniques contribute with mitigating

environmental impacts and accomplish government regulations.

Acknowledgements The authors would like to thank the management of Pluspetrol Norte for their support and permission to publish this paper. The authors also show their gratitude to the engineering department of Pluspetrol for their ideas to developthis work. References 1. Silvia Blanco, Claudia Aguirre, “ Formacion Vivian;

Estudio Sedimentologico, Petrofisico, Diagenetico, Mineralogico, De Microscopia Electrónica y Bioestratigrafico.Compañía LCV.

2. J. Altamirano C.M., Ricardo C.B. de Melo, Gino Di Lullo “ Case history Evaluation of RPM on Conform Fracturing Applications”, paper SPE 94352

3. P.K. Wanjau, J. Joseph, P. Cianmmetti, K. Lassel, P. Akunna “ A New Technique for Carbon/Oxygen Logging through Gravel Packs and Others Special completations”

4. Enrique Estrada Vera, “Reingeniería en Control de Agua con Incremento de Producción de Petróleo en Campos Maduros – Campo Shiviyacu Lote 1AB, Selva Norte del Perú., INGEPET 2005.

6 SPE 108039

Before Job After Job Before Job After JobJibarito 01 Jibarito 486 319 10864 310Jibarito 06 Jibarito 517 486 9351 123Jibarito 12 Jibarito 235 508 10443 885Jibaro 03 Jibaro 268 266 11017 6078

Shiviyacu 13 Shiviyacu 253 272 13089 8418Jibarito 08 Jibarito 765 873 12602 7426Jibarito 07 Jibarito 415 532 9739 5675

2939 3256 77105 28915Total

Oil Production (BOPD) Water Production (BWPD)Well Oilfield

Before Job After Job Before Job After JobShiviyacu 03 Shiviyacu 69 116 10423 1249Shiviyacu 08 Shiviyacu 139 360 7619 8Shiviyacu 10 Shiviyacu 127 376 9200 1653Shiviyacu 28 Shiviyacu 250 363 11157 32

585 1215 38399 2942Total

Oil Production (BOPD) Water Production (BWPD)Well Oilfield

RESULTS OF WATER CONTROL

CASE I

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SPE 108039 7

Figura 6 : Seccion Estructural

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GENERALIZED STRATIGRAPHIC COLUMNPERU - NORTHERN MARAÑON BASINpluspetrol

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8 SPE 108039

VIVIAN “A” SAND

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SHALE

VIVIAN“B”

SAND

VIVIAN“B”

SHALE

TOP

BOTTOM

OIL

CLAY

CLAY

OIL

BOTTOM

TOP

VIVIAN“B”

SAND

GRAPI0 150SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200SFLU

OHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

VIVIAN “A” SAND

VIVIAN “B” SHALE

BOTTOM

TOP

VIVIAN “A” SAND

VIVIAN “B” SHALE

VIVIAN “A” SAND

VIVIAN “B” SHALE

BOTTOM

TOP

VIVIAN“B”

SHALE

VIVIAN“B”

SAND

VIVIAN“B”

SHALE

TOP

BOTTOM

VIVIAN“B”

SHALE

VIVIAN“B”

SAND

VIVIAN“B”

SHALE

VIVIAN“B”

SHALE

VIVIAN“B”

SAND

VIVIAN“B”

SHALE

TOP

BOTTOM

OIL

CLAY

CLAY

OIL

BOTTOM

TOP

VIVIAN“B”

SAND

OIL

CLAY

CLAY

OIL

OIL

CLAY

CLAY

OIL

BOTTOM

TOP

VIVIAN“B”

SAND

GRAPI0 150SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200SFLU

OHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

GRAPI0 150SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200SFLU

OHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

GRAPI0 150SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200SFLU

OHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

B

A4

A3

A2

A1

C

Lateral Bar

Longitudinal Bar

VIVIAN “A” SAND

VIVIAN “B” SHALE

VIVIAN “A” SAND VIVIAN “A” SAND

COARSE

V. FINE

COARSE

GRAPI0 150

SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200

SFLUOHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

Lateral Bar

Longitudinal Bar

VIVIAN “A” SAND

VIVIAN “B” SHALE

VIVIAN “A” SAND VIVIAN “A” SAND

COARSE

V. FINE

COARSE

GRAPI0 150

SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200

SFLUOHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

Lateral Bar

Longitudinal Bar

Lateral Bar

Longitudinal Bar

VIVIAN “A” SAND

VIVIAN “B” SHALE

VIVIAN “A” SAND

VIVIAN “B” SHALE

VIVIAN “A” SAND

VIVIAN “B” SHALE

VIVIAN “A” SANDVIVIAN “A” SANDVIVIAN “A” SAND VIVIAN “A” SAND

COARSE

V. FINE

COARSE

VIVIAN “A” SAND

COARSE

V. FINE

COARSE

VIVIAN “A” SAND

COARSE

V. FINE

COARSE

GRAPI0 150

SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200

SFLUOHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

GRAPI0 150

SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200

SFLUOHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

GRAPI0 150

SPCMV-130 20

DEPTHFT

RESFLAG 5 0

ILDOHMM0.2 200

SFLUOHMM0.2 200

PHIE 0.3 -0.3

SWEDEC2 0

VCLDEC0 1

VCARBDEC0 1

10050

10100

10150

10200

B

A4

A3

A2

A1

C

B

A4

A3

A2

A1

C

Figure N° 3

Figure N° 4

VIVIAN “B”

MAIN VIVIAN

SPE 108039 9

3700

3725

VIVIAN FORMATION

CHONTA FM.

VIVIAN RESERVOIR

B

A

3700

3725

VIVIAN FORMATION

CHONTA FM.

VIVIAN RESERVOIR

B

A

3700

3725

VIVIAN FORMATION

CHONTA FM.

VIVIAN RESERVOIR

B

A

2 KM

GRGAPI0 150

SPCMV-130 20

ACALINCH10 20

DEPTHM

RESFLAG 5 0

PAYFLAG 5 0

ILDOHMM0.2 200

SNOHMM0.2 200

KIMD2 2000

PHIEDEC0.3 -0.3

SWEDEC2 0

BVWDEC0.3 -0.3

VCLDEC0 1

VCARBDEC0 1

PHIEDEC1 0

TOP VIVIAN "C" SAND

TOP "W" SHALE MARKER

TOP VIVIAN "B" SAND

TOP "X" SHALE MARKER

TOP VIVIAN "A" SAND

TOP VIVAN "A3" SAND

TOP VIVIAN "A2" SAND

TOP VIVIAN "A1" SAND

TOP VIVIAN "Z0" SH

TOP VIVIAN "A0" SAND

TOP CHONTA FORMATION

2900

2925

2950

VIVI

AN

FO

RM

ATI

ON

LWR

VIV

IAN

MA

IN V

IVIA

N O

R “A

” S

AN

DUP

PE

R V

IVIA

N

“B”UNIT

“C”UNIT

GOOD RESERVOIR

K = 500 – 5000 md

VERTICALBARRIER

K = 1 – 5 md

GOOD RESERVOIRK = 500 – 5000 md

VIVIAN “A” SANDCOARSESANDWITHOIL

VERYFINESANDWITHKAOLINMATRIX

COARSESANDWITHOIL

OIL

SHALE

CLAY

OIL

BOTTOM

TOP

VIVIAN“B”

SAND

SHALE

SHALECLAY

FINETO

MEDIUMGRAINSANDS

LAMINATEDWITH

VERY FINESANDSWITH

KAOLINMATRIX

FLU

VIAL

DEP

OSI

TS W

ITH

TID

AL IN

FLU

ENC

EES

TUAR

INE

MEA

ND

ERIN

G C

HAN

NN

ELS

2 KM2 KM

GRGAPI0 150

SPCMV-130 20

ACALINCH10 20

DEPTHM

RESFLAG 5 0

PAYFLAG 5 0

ILDOHMM0.2 200

SNOHMM0.2 200

KIMD2 2000

PHIEDEC0.3 -0.3

SWEDEC2 0

BVWDEC0.3 -0.3

VCLDEC0 1

VCARBDEC0 1

PHIEDEC1 0

TOP VIVIAN "C" SAND

TOP "W" SHALE MARKER

TOP VIVIAN "B" SAND

TOP "X" SHALE MARKER

TOP VIVIAN "A" SAND

TOP VIVAN "A3" SAND

TOP VIVIAN "A2" SAND

TOP VIVIAN "A1" SAND

TOP VIVIAN "Z0" SH

TOP VIVIAN "A0" SAND

TOP CHONTA FORMATION

2900

2925

2950

VIVI

AN

FO

RM

ATI

ON

LWR

VIV

IAN

MA

IN V

IVIA

N O

R “A

” S

AN

DUP

PE

R V

IVIA

N

“B”UNIT

“C”UNIT

GOOD RESERVOIR

K = 500 – 5000 md

VERTICALBARRIER

K = 1 – 5 md

GOOD RESERVOIRK = 500 – 5000 md

VIVIAN “A” SANDCOARSESANDWITHOIL

VERYFINESANDWITHKAOLINMATRIX

COARSESANDWITHOIL

GOOD RESERVOIR

K = 500 – 5000 md

VERTICALBARRIER

K = 1 – 5 md

GOOD RESERVOIRK = 500 – 5000 md

VIVIAN “A” SANDCOARSESANDWITHOIL

VERYFINESANDWITHKAOLINMATRIX

COARSESANDWITHOIL

OIL

SHALE

CLAY

OIL

BOTTOM

TOP

VIVIAN“B”

SAND

SHALE

SHALECLAY

FINETO

MEDIUMGRAINSANDS

LAMINATEDWITH

VERY FINESANDSWITH

KAOLINMATRIX

FLU

VIAL

DEP

OSI

TS W

ITH

TID

AL IN

FLU

ENC

EES

TUAR

INE

MEA

ND

ERIN

G C

HAN

NN

ELS

Figure N° 5

Figure N° 6

10 SPE 108039

New Oil / Water ContactNew Oil / Water Contact

JIBARITO 06JIBARITO 06

1

10

100

0 1000 2000 3000 4000 5000

CUMULATE OIL

OIL

CU

T (%

)

OIL CUT

5.2 %

78.8 %

10

100

1000

10000

100000

Mar-91 Nov-93 Aug-96 May-99 Feb-02 Nov-04 Aug-07

BFPD BOPD

9869 BFPD

609 BFPD

Water Production Reduction : 9228 BWPD

486 BOPDx 609BFPD x20.2% WCUT

AFTER

EZ @ 2913.8

JIBARITO 06JIBARITO 06

1

10

100

0 1000 2000 3000 4000 5000

CUMULATE OIL

OIL

CU

T (%

)

OIL CUT

5.2 %

78.8 %

1

10

100

0 1000 2000 3000 4000 5000

CUMULATE OIL

OIL

CU

T (%

)

OIL CUT

5.2 %

78.8 %

10

100

1000

10000

100000

Mar-91 Nov-93 Aug-96 May-99 Feb-02 Nov-04 Aug-07

BFPD BOPD

9869 BFPD

609 BFPD

Water Production Reduction : 9228 BWPD

10

100

1000

10000

100000

Mar-91 Nov-93 Aug-96 May-99 Feb-02 Nov-04 Aug-07

BFPD BOPD

9869 BFPD

609 BFPD

Water Production Reduction : 9228 BWPD

486 BOPDx 609BFPD x20.2% WCUT

AFTER

EZ @ 2913.8

AFTER

EZ @ 2913.8

CASO I : JIBARITO 06

Figure N° 7

Figure N° 8 Figure N° 9

SPE 108039 11

360 BOPDx 368 BFPD x 2.1% WCUT

SPCmv-120 30

CALCIN6 16

DEPTHM

( PERF )0 7

ILDCohmm0.2 200

SFLUCohmm0.2 200

BVWDEC0.3 0

PHIEDEC0.3 0

RESFLAG 10 0

PAYFLAG 10 0

VCLdec0 1

SANDDECIMAL0 1

VIVIAN "B" SD TOPVIVIAN FM TOP

VIVIAN RES TOPVIVIAN "A" SD TOP

CHONTA FM TOP

3025

3050

10

100

1000

10000

100000

Apr-75 Oct-80 Mar-86 Sep-91 Mar-97 Sep-02 Feb-08

BFPD BOPD

Reduccion de Agua : 7611 BWPD

7758 BFPD

368 BFPD

1

10

100

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

CUMULATE OIL

OIL

CU

T (%

)

OIL CUT

1.8 %

97.9 %

360 BOPDx 368 BFPD x 2.1% WCUT

SPCmv-120 30

CALCIN6 16

DEPTHM

( PERF )0 7

ILDCohmm0.2 200

SFLUCohmm0.2 200

BVWDEC0.3 0

PHIEDEC0.3 0

RESFLAG 10 0

PAYFLAG 10 0

VCLdec0 1

SANDDECIMAL0 1

VIVIAN "B" SD TOPVIVIAN FM TOP

VIVIAN RES TOPVIVIAN "A" SD TOP

CHONTA FM TOP

3025

3050

SPCmv-120 30

CALCIN6 16

DEPTHM

( PERF )0 7

ILDCohmm0.2 200

SFLUCohmm0.2 200

BVWDEC0.3 0

PHIEDEC0.3 0

RESFLAG 10 0

PAYFLAG 10 0

VCLdec0 1

SANDDECIMAL0 1

VIVIAN "B" SD TOPVIVIAN FM TOP

VIVIAN RES TOPVIVIAN "A" SD TOP

CHONTA FM TOP

3025

3050

SPCmv-120 30

CALCIN6 16

DEPTHM

( PERF )0 7

ILDCohmm0.2 200

SFLUCohmm0.2 200

BVWDEC0.3 0

PHIEDEC0.3 0

RESFLAG 10 0

PAYFLAG 10 0

VCLdec0 1

SANDDECIMAL0 1

VIVIAN "B" SD TOPVIVIAN FM TOP

VIVIAN RES TOPVIVIAN "A" SD TOP

CHONTA FM TOP

3025

3050

10

100

1000

10000

100000

Apr-75 Oct-80 Mar-86 Sep-91 Mar-97 Sep-02 Feb-08

BFPD BOPD

Reduccion de Agua : 7611 BWPD

7758 BFPD

368 BFPD

10

100

1000

10000

100000

Apr-75 Oct-80 Mar-86 Sep-91 Mar-97 Sep-02 Feb-08

BFPD BOPD

Reduccion de Agua : 7611 BWPD

7758 BFPD

368 BFPD

1

10

100

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

CUMULATE OIL

OIL

CU

T (%

)

OIL CUT

1.8 %

97.9 %

1

10

100

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

CUMULATE OIL

OIL

CU

T (%

)

OIL CUT

1.8 %

97.9 %

Figure N° 11

Figure N° 10

CASO II – SHIVIYACU 28

Figure N° 12

12 SPE 108039

Figure N° 13

Figure N° 14

100

1000

10000

28/05/05 05/09/05 14/12/05 24/03/06 02/07/06 10/10/06 18/01/07 28/04/07

DATE

BPD

1

10

100

BOPD BWPD OIL CUT

CASO III : JIBARO 06

Figura N° 16

Figure N° 15