Enhanced Oil Recovery in a Multilayer Complex ReservoirCasabe Project Case Study

Authors: Adriano Lobo (ECP), Carlos Chaparro (ECP), Jose Francisco Zapata (ECP), Ana Maria Jimenez (ECP), Thaer Gheneim (SLB), Annalyn Azancot (SLB)

Project BackgroundDiscovered in 1941~1,450 wells drilled by 2015Active waterfloodingFive Spot patterns~15 acre spacing Producing formations: Colorado, Mugrosa, La PazFluvial environmentLayered sand/shale sequence~ as many as 25 zones/producers18-25 API oil with ~ 30-80 cp viscosityOriginal pressure ~ 1,500 psia, Current range from 400-1,200 psia• k = 50-300 mD• RF ~ 20% pattern WF

-93.56 36.29SPC MD

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3600

(3650)

(3692)

30450.00 30.00NORMAL

tope_COLORADO BS A0 F607 tA1b tA1d

A2

A2i

A3

CSBE0033 [MD]-100.73 14.21SPC MD

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3636

29890.00 30.00N38

BS A0 A1 tA1b tA1d

A2

A2i

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bA3

CSBE0097 [MD]16.53 -17.11SPC MD

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30730.46 72.49AHT60

tope_COLORADO BS A0

A2

A3

A1 tA1d tA1b bA3

A2i

CSBE1068 [MD]

OVERBANK

CHANNEL BARS

CREVASSE

VERTICAL HETEROGENEITY DUE TO CHANNEL STACKING

MODIFIED FROM RAMON Y CROSS, 1997

Vertical and Horizontal Heterogeneity

Relative Preservation Of The Channels Sandstones Under Low And High A/S Conditions

Project Background– Large difference in mobility between oil and water in Casabe (Mw,o ~ 25)

– Maturity of secondary recovery create several operational problems in the field

• Increase of the water cut

• water influxes

• Increased volume of produced sand, etc.

– Heterogeneities create irregular water fronts, causing early water breakthrough

Source: Integrated Waterflood Asset Management. THAKUR Ganesh y SATTER

Abdus. 1998.

Where:

EV = Volumetric Efficiency

EA = Areal Efficiency

EI = Vertical Efficiency

Ev= EA x EI

IMPROVE SWEPT EFFICIENCY

↑Increase Water

Viscositydrd

DrD

k

kM

Mobility Ratio Modification

↓

5 Year EOR Cycle Time

Screening

Pilot Design

Pilot Drilling

& Installation

Pilot Operation &

Surveillance

Pilot Expansion

Full Field Devt Plan

Lab/Tracer Studies

No Economic

Technique

Final Costs

Uneconomic

Incremental not

Delivered or Proven

Follow-up

Doesn’t Deliver

Full Field

Uneconomic

0 6 12 18 36 -42 54-60

Go-No Go Decisions

Technique

Pilot Areas

Budget

Predictions

Pilot Plan

AFEs

Proof of Concept

Early Cash

Reserves & FID

Deliverables

EOR Project Implementation Process + Focus Team

Project Manager

Reservoir Engineer

G&G

Production Technologist

Well Construction Engineer

Facilities Engineer

Production Optimization

Economic Analyst

Supply Chain Support

ScreeningConceptual

DesignPilot Design

Pilot Well Construction

Pilot Operation

Lab StudiesEOR Prefer

Vendor Selection

EOR Contract

Product & Facilities Delivery

Facilities Design

Facilities

Contract

Facilities Construction

InterWell Tracers

Contract

Well Intervention

InterWell Tracers

Tracer Analysis

0 6 12 18 24

Months

MonitoringTech.

InstallationBaseline

Construction

Screening

Screening criteria for EOR processes• Formation type/lithology• Reservoir geology• Oil Composition and Oil Viscosity• Formation Water Salinity and Divalents• Reservoir Temperature• Formation Permeability

Operational issues to consider• Availability of injecting agents (Water, Gas,

CO2, N2)• Pattern configuration and well spacing• Well Completion • Facilities configuration and constrains• Energy• Environmental and Legal Regulations

EORt Workflow

Conceptual DesignTwo Polymer Flooding Pilots for mobility control and Sor

Reduction EOR; variation in chemical make up for differentK/V shale

– One in Average Rock Quality, swept.

– One in Best Rock Quality, swept

Two layers comprising >30% of OOIP

EOR Pilot Areas

B6

B3((4 arrangements*3 streamlines)/4)+(1 arrangement*4 streamlines) = 4 Wells

Injector

Producer

Observation

9

Oil and water saturations

Polymer concentrationLow High

EOR Experimental Tests Digital RockViscosity modification with

HMPA Polymer

Viscosity modification with Associative Polymer

Surfactant Phase Behavior

Core Flooding

Tracer Technology

Tracer injection Zone

InjectorProducer

Sampling Valve

InterWell Tracer Irruptions Map

Black 2 FBA CSBE-1292 A2i

Red 4 FBA CSBE-1292 A2

Green 2,3,4,5 FBA CSBE-1313 A2i

Blue 3,5 FBA CSBE-1313 A2

Pink 2,6 FBA CSBE-1222 A2i

Grey 2,3,4 FBA CSBE-1222 A2

Oranje 3,5 DFBA CSBE-1304 A2

Yellow 3,4 FBA CSBE-1304 A2i

• InterWell Tracer Irruption observed on both sands A2(Upper) and A2i (Lower)

• InterWell Tracers confirm Sand deposition direction.• Irruption on 2nd line production wells confirm complex

channeling system.• Base on irruption times severe channeling is observed

between CSBE 1222 (INY) and CSBE-1159 (Central Well)

A2i Sand Example

Viscosity reduction test on injection valves

Circulation Valves

No reduction effect on 9 mm circulation valves. Dramatic viscosity reduction on flow regulation valves

cEOR Project Design

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1018000

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CB-0058R

CB-0164R

CB-0367

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CB-0417

CB-0443

CB-0468

CB-0515

CB-0520

CB-0526

CB-0534CB-0535

CB-0536CB-0537

CB-0543CB-0544

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CB-1159CB-1159

CB-1162

CB-1164CB-1164

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CB-1289CB-1292

CB-1296

CB-1301

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CB-1308

CB-1313

CB-1349

CB-1520

Producer

Polymer/Tracer Inj.

Observation

• Block 6. 4 Polymer Injector Wells 9 Oil Producer Wells 1 Observation Well Comingle Production Selective Polymer Injection

Completion Scheme

Pattern Distribution

Porous Media

• Four (1/4) Injectors

Five Spot Pattern

• Four injectors

Four Inverted Five Spot Patterns

• Sixteen Injectors

Four Inverted Five Spot Pattern

Simulation Cases

Implementation of the surveillance plan

Selective injection

Water flow regulator valves

Commingled production

Low Production Rates

Poor production monitoring

No real time data for production/injection optimization

Sand production

Different type of ALS with rods

High water cut

Casing/tubing damage

Preparation & Baseline

• Understand actual well behavior.

• Know actual well mechanical conditions

• Identify prod/inj. enhancement opportunities before the pilot

• Baseline preparation

Monitoring During Pilot

• Monitoring key variables to make decisions related to changes in injection parameters.

• Ensure wells are operating at optimum conditions

Pilot Evaluation

Pilot Expansion

No Go

Surveillance plan

What are we injecting?Is the polymer is under specifications?

QinjPinj

Where we are injecting? All layers are taking polymer?

Effect on the producer. Increase of oil production?

Corrosion and MultiFinger logsPLT at different flow rates (SIP analysis)Multiphase flow meters

Injectors:• Initial injection profile• Injectivity tests• Sand in annular

Observation well:• Initial oil saturation• Initial formation pressure

Reservoir:• InterWell tracers

Preparation & Baseline Monitoring During Pilot

Initial Evaluation:

Producers:• Casing integrity evaluation• Initial production distribution• Production baseline

DSLWS surface pumpsRST silicon activation log

RST-C/OXPT

Well connectivityChannel sizeBreakthrough times NT in Casabe

Data Acquisition program:

NT in Casabe

Preparation & Baseline Monitoring During Pilot

Frecuency 31-Jan-15 28-Feb-15 31-Mar-15 30-Apr-15 31-May-15 30-Jun-15 31-Jul-15 30-Aug-15 30-Sep-15 30-Oct-15 30-Nov-15 31-Dec-15

Prodution monitoring with multiphase flow meters

(# of well tests monthly)2 well test daily 60 56 60 60 60 60 60 60 60 60 60 60

Wellhead preassure Real time 30 28 30 30 30 30 30 30 30 30 30 30

ALS parameters Real time 30 28 30 30 30 30 30 30 30 30 30 30

PLT with wireline Each 6 months 1 1 2

Downhole pressue gauges # gauges installed 4 5 7 7 7 7 7 7 7 7 7 7

Polymer injection presure and rate Daily 30 28 30 30 30 30 30 30 30 30 30 30

Viscosity, concentration, filter ratio Daily 30 28 30 30 30 30 30 30 30 30 30 30

Polymer stock Weekly 4 4 4 4 4 4 4 4 4 4 4 4

Injection profiles Each 2 weeks 2 2 2 2 2 2 2 2 2 2 2 2

Oil saturation Each 6 months 1 1

Formation pressure

(PLT and downhole pressure gauges)As requiered 1 1 1 1 2

QA/QC (days per month)

QC polymer, polymer breaktrough in producers ,

water quality, viscosity, filter ratio, concentration

Monthly 10 10 10 10 10 10 10 10 10 10 10 10

Polymer specifications

Prod/Inj AnalysisPolymer injection process

Fluids movement in reservoir

Flowing and Formation pressures

EOR Pilot Performance Evaluation

Original Oil Saturation• Shows good Original Oil Saturation• Not sweep oil

Well LocationObservation Well

OBSERVATION WELL OBJECTIVES

• Observation well to evaluate

increase in sweep efficiency of

polymer injection in A2/A2i

sands.

• Infill drilling well to evaluate the

efficiency of reduction in the

injection – production pattern

spacing.

RST BaseRST TL1

RST TL1RST TL2

RST TL2RST Base

Average So

A B C D E F

B: Oil saturation increase between October 2014 and April 2015

D: Oil saturation decrease between Abril 2015 y October 2015

F: Total Oil Saturation Change entre October 2014 y October 2015

RST Time Lapse. A2 Sand

RST BaseRST TL1

RST TL1RST TL2

RST TL2RST Base

So Promedio

A B C D E F

RST Time Lapse. A2i Sand

B: Oil saturation change between October 2014 and April 2015

D: Oil saturation change between Abril 2015 y October 2015

F: Total Oil Saturation Change entre October 2014 y October 2015

CSBE-01PO

1. Initial Saturation Condition :Original So

2. RST @ 6 months: So increase, oilfront reached observation well.

3. RST @ 1 year:• Preferential drainage.• Channels with So reduction

due polymer flood effect, oilis pushed to neighbor wells.

• Channels with So increasedue polymer flood effect,entrapment due to lack ofdrainage points.

4. Proof of concept of areal sweepincrease.

Flow Behavior

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CAUDAL BLS

PRESION PSI

Injector Well CSBE-1222

WFR No WFR

Polymer

CSBE-1222 shows good injectivity both water and polymer.1. Concentration reduction to 400 ppm2. Conformance with mother solution at 3000 ppm - A2i 3. Hypochlorite Clean Up - A2

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CAUDAL BLS

PRESION PSI

WFR No WFR

Polymer

1

2

Injector Well CSBE-1304

CSBE-1304 shows reduction of injectivity due lack of drainage points.1. Concentration reduction to 400 ppm2. Hypochlorite Clean Up - A2. Injection increased.

B6 Pilot Pattern Performance Prior polymer injection, patternoptimization shows a increase inoil production.Polymer Injection stabilizationoccurred since January 2015.Dramatic water productiondecrease after polymer injection.Oil Production Increase after 8-9months of polymer injection.

B6 Pilot Pattern Performance

Oil production increased after pattern optimization. Afterpolymer injection oil production decrease slightly butwater production decrease drastically.After 8-9 month oil increase.

Sweep efficiency increaseobserved after WaterFlooding optimization.Polymer Flood show sweepefficiency over Waterflooding. Decrease barrel ofwater injected by barrel oilproduced.

B6 Pilot Pattern Performance

4.8 BWI/BOP

3.7 BWI/BOP

2.5 BWI/BOP

Facilities Installation

Polymer Unit Control Panel

Polymer Mixing and Injection Unit

Polymer Mixing and Injection Unit

Polymer injection started in October 28 2014, in four polymer injector wells. Total injection capacity is 3.000 B/D of 500 ppm polymer solution at 2,000 psi

Individual pump for each injector is used

to allow individual pressure control

Conclusions• Fast Track EOR is feasible and achievable

With the right integration of Operator and Service Provider(s):18 months to pilot online36 months to proof of concept

• One Stop Shop to minimized tender, decision and handovers delays• Successful Implementation of Casabe Pilot Project• A surveillance plan for any EOR pilot is key to ensure the collection of critical data that will

allow a proper evaluation of the pilot.• The surveillance plan is determined by the characteristics and challenges of each field.• The implemented plan is far more robust than conventional surveillance used at the field.• Design, Operation & Surveillance must still be best in class and focus on earliest proof of

concept• A structured Team dedicated to the project is fundamental for success• Synergy between different players across the organization are crucial to implement a fast

track project