Successful Implementation of anSuccessful Implementation of anIntegrated Production NetworkIntegrated Production Network

Model for the Heera FieldModel for the Heera Field

Pavan Aggarwal, ONGC LtdPavan Aggarwal, ONGC LtdManickam Nadar, EPS Ltd.Manickam Nadar, EPS Ltd.

Presenter:Presenter:

Pavan Aggarwal, ONGCLPavan Aggarwal, ONGCL

ASME / API / ISO Gas Lift Workshop,

Doha, QatarFeb 4-8, 2007

ASME Gas Lift Workshop, 4-8 Feb 2007, Doha, Qatar 2

Tangible ResultsTangible Results

Successful construction and calibration of a large Successful construction and calibration of a large scale, complex production network model which is scale, complex production network model which is robust and reliablerobust and reliableFirst full field integrated production model First full field integrated production model operational in Indiaoperational in IndiaImplementation of recommendations (ongoing) has Implementation of recommendations (ongoing) has so far resulted in an increased production of 1700 so far resulted in an increased production of 1700 BOPD (4%)BOPD (4%)Model and workflows are being integrated into Model and workflows are being integrated into ongoing gas lift surveillance and field optimization ongoing gas lift surveillance and field optimization proceduresprocedures

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OutlineOutline

IntroductionIntroductionObjectivesObjectivesModel Construction, Calibration & AnalysisModel Construction, Calibration & AnalysisOptimization RecommendationsOptimization Recommendations

Well Models: Well Models: GL Design improvementsGL Design improvementsNetwork Model: Network Model: Field Gas Lift reallocationField Gas Lift reallocation

Implementation StrategyImplementation StrategyResults achieved so farResults achieved so farConclusions & Lessons LearnedConclusions & Lessons Learned

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IntroductionIntroduction

Heera Field, offshore Heera Field, offshore Mumbai, India.Mumbai, India.

OOIP OOIP –– 285 MMT.285 MMT.Mature Producing FieldMature Producing Field119 GL Producers + 59 119 GL Producers + 59 InjectorsInjectorsCurrent Production Current Production ~45,000 ~45,000 stbostbo/Day/DayFormation GOR 120 mFormation GOR 120 m33/m/m33

Average WC ~55%Average WC ~55%

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ObjectivesObjectives

Present a case history describing successful Present a case history describing successful implementation of optimization methodology in a implementation of optimization methodology in a major gas lifted field.major gas lifted field.

Outline the structure and methodology for Outline the structure and methodology for constructing and calibrating a large integrated constructing and calibrating a large integrated production model.production model.

Provide an optimization solution which takes account Provide an optimization solution which takes account of network and other constraints.of network and other constraints.

Illustrate the potential applications in running the Illustrate the potential applications in running the completed model in optimization mode. completed model in optimization mode.

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Well ModelingWell ModelingNodal AnalysisNodal Analysis

Well model construction:Well model construction:Reservoir, production string & artificial lift systemReservoir, production string & artificial lift system

Calibration with FGS/production test data (at date Calibration with FGS/production test data (at date of FGS)of FGS)Update model to current well production test dataUpdate model to current well production test dataCalibration of lift gas injection parameters Calibration of lift gas injection parameters Use updated model to perform gas lift diagnostics Use updated model to perform gas lift diagnostics and identify uplift potentialand identify uplift potentialGas Lift well performance surfaces generated for Gas Lift well performance surfaces generated for the network model the network model 119 wells on 15 well platforms119 wells on 15 well platforms

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Well Performance CurveWell Performance Curve

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Well ModelingWell ModelingPotential Uplift Potential Uplift

Well Gas lift designs were modified / Well Gas lift designs were modified / optimized to achieve the following: optimized to achieve the following:

Ensure single point liftEnsure single point liftImprove gas lift depth using the available Improve gas lift depth using the available injection pressureinjection pressureUpdate gas lift design for changed inflow Update gas lift design for changed inflow conditionsconditionsUse of orifice valves at operating mandrel Use of orifice valves at operating mandrel stationstation

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Well Modeling ResultsWell Modeling Results

Gas Lift Redesign / Optimization potential: Gas Lift Redesign / Optimization potential: 22 Candidates identified with more than 50 BOPD 22 Candidates identified with more than 50 BOPD upliftuplift5 candidates require only gas lift rate 5 candidates require only gas lift rate optimizationoptimization17 candidates for gas lift redesign17 candidates for gas lift redesign

Of these, 12 candidates with potential gain of more than Of these, 12 candidates with potential gain of more than 100 BOPD (high priority) 100 BOPD (high priority) –– See chartSee chart

0

50

100

150

200

250

300

HC-5 HSA-2 HD-10 HC-3 HB-12 HF-10 HSB-2 HT-10 HC-2 HSA-1 HSB-1 HSB-5

Well Name

Oil

Gai

n (B

OPD

)

Gain Estimated

Gain Achieved

No WO Job Carried out

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Network ModelingNetwork Modeling

PVT: Black Oil; 4 different fluid PVT datasets.PVT: Black Oil; 4 different fluid PVT datasets.Wells: well head performance curvesWells: well head performance curvesPipe/Flow Lines: 452 pipe elements Pipe/Flow Lines: 452 pipe elements

Production & gas injection lines on facilities and well Production & gas injection lines on facilities and well satellite platforms (including risers, flow lines, elevations, satellite platforms (including risers, flow lines, elevations, sea/air environment, pipeline insulation etc.):sea/air environment, pipeline insulation etc.):

Process Equipment:Process Equipment:Multistage separators (4xHP/1xLP/1xLLP)Multistage separators (4xHP/1xLP/1xLLP)Gas lift compressors (5)Gas lift compressors (5)heat exchangers, valves, chokes, etc.heat exchangers, valves, chokes, etc.

Recycle loop (LP gas recovery)Recycle loop (LP gas recovery)ICP and Neelam satellites (using ICP and Neelam satellites (using SourceSource objects)objects)

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Network Model: ConstructionNetwork Model: Construction

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Network Model: ConstructionNetwork Model: Construction

Process Modeling includes:•Flowlines, block valves•Chokes, control valves•Separators, Heat Exchangers•Compressors, Pumps•Various constraints (pressure, flow, temperature) in the network

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Optimization Scenarios Optimization Scenarios

Optimization Scenarios Investigated with Optimization Scenarios Investigated with History matched Model:History matched Model:

Base Case Base Case –– gas lift reallocation (Network Gas gas lift reallocation (Network Gas Lift Optimization)Lift Optimization)

Optimum separator pressureOptimum separator pressure

Optimum gas lift header pressureOptimum gas lift header pressure

Compressor shutCompressor shut--inin

Pipeline dePipeline de--bottleneckingbottlenecking

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Network Optimization GainsNetwork Optimization Gains

0

50

100

150

200

250

300

350

HA HB HC HD HE HF HQ HR HS HSA HSB HT HV HX HYPlatform

Oil

Gai

n (S

TB/d

)

Estimated Gain

Achieved Gain

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Optimization ResultsOptimization ResultsOptimization gains (Base Case):Optimization gains (Base Case):

6%6%8%8%Lift Gas Savings Lift Gas Savings

900 900 bopdbopd1500 1500 bopdbopdField gas lift Field gas lift reallocationreallocation

800 800 bopdbopd1500 1500 bopdbopdWell GL designsWell GL designs

Achieved gainAchieved gainPredicted gainPredicted gain

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Pipeline DePipeline De--bottleneckbottleneck

HC-HA Pipeline size, in.

HC Oil production rate, STB/Day

HC Water Production rate, STB/Day

HC Lift gas consumed, Mscm/day

HC Production manifold pressure, Kg/cm2g

10 4347 2261 90382.2 13.87

14 4792 2512 94784.4 9.08

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HeeraHeera ReRe--development development (New pipeline)(New pipeline)

HVHX-12-WF

HXHRG-12-WF

HBHE-10-WF

HEHRG-10-WF

HYHRG-12-WF

HSAHRG-18-WF

HSBHRG-14-WF

HSHRG-12-WF

HTHRA-12-WF

HRHRG-10-WF

HQHA--10-WF

HCHA-10-WF HFHA-10-WF

HDHA-12-WF

HBHA-10-WF HEHA-12-WF

B134HI-12-WF

HIHRC-14-WF

HCHI-10-WF

HJHRC-12-WF

HSCHRG-16-WF

HZHRG-12-WF

HRG

HZ

HRC

HJ

HC HI

URAN

HB

HX

HE

HV

HY

HSA

HSB

HT

HS

HR

HQ HD

HF

HRA

HA

HE_1 HB_1

HX_1

HI_1

HSC

B-134A HC_1

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ImplementationImplementation

Stepwise, Stepwise, fieldwidefieldwideOn each well: change On each well: change sstabilize tabilize monitor monitor then review resultsthen review results

Good Good –– continue to the next stepcontinue to the next stepNot good Not good –– review well model and updatereview well model and update

Work as a teamWork as a teamProduction rate changes better monitored at Production rate changes better monitored at the facilities level (the facilities level (measurable benefitsmeasurable benefits))Individual production well tests are critical Individual production well tests are critical for well model calibration and reviewfor well model calibration and review

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ConclusionsConclusionsAn integrated production model of the Heera Field has been An integrated production model of the Heera Field has been successfully constructed, history matched and used to successfully constructed, history matched and used to optimize lift gas allocation for increasing oil production. Thisoptimize lift gas allocation for increasing oil production. Thisis the first model on this scale which has been successfully is the first model on this scale which has been successfully implemented in Indiaimplemented in IndiaOptimization results predict a potential uplift of 6Optimization results predict a potential uplift of 6--8% in oil 8% in oil production. Early implementation in the field to date production. Early implementation in the field to date through well interventions and lift gas reallocation have so through well interventions and lift gas reallocation have so far raised oil production by far raised oil production by 1700 BOPD (4%)1700 BOPD (4%)Optimization runs with the network model help assess the Optimization runs with the network model help assess the costcost--benefit impact of changes in separator pressure and benefit impact of changes in separator pressure and gas lift header pressuresgas lift header pressuresThe network model can be used to investigate the benefits The network model can be used to investigate the benefits of upof up--sizing pipelines. Additional economic analysis is sizing pipelines. Additional economic analysis is required to support such recommendationsrequired to support such recommendationsA calibrated & updated network model can be used for A calibrated & updated network model can be used for optimizing the size & location of future pipelines in the fieldoptimizing the size & location of future pipelines in the field

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Lessons LearnedLessons LearnedModeling and optimization of field production networks should beModeling and optimization of field production networks should bean integral part of artificial lift surveillance, maintenance anan integral part of artificial lift surveillance, maintenance and d upgradingupgradingBuilding or analyzing results of models often results in new ideBuilding or analyzing results of models often results in new ideas as and gainsand gains

Collaborative thinkingCollaborative thinkingChallenging existing design criteriaChallenging existing design criteria

Challenges in implementing model recommendations: Challenges in implementing model recommendations: GLV changes could be done in 2/3GLV changes could be done in 2/3rdrd of the planned wells in of the planned wells in HeeraHeeraWell intervention jobs have inherent risks. Careful planning & Well intervention jobs have inherent risks. Careful planning & management support is requiredmanagement support is required

A MultiA Multi--discipline team (well production engineer, facilities discipline team (well production engineer, facilities engineer and operations personnel) was required to coengineer and operations personnel) was required to co--ordinate ordinate the jobs, and monitor and analyze the resultsthe jobs, and monitor and analyze the results

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AcknowledgementAcknowledgement

The authors wish to thank the management The authors wish to thank the management of Neelam and Heera Asset (ONGC) for of Neelam and Heera Asset (ONGC) for permission to publish this paper and for their permission to publish this paper and for their continuing commitment in maintaining the continuing commitment in maintaining the model and implementing the optimization model and implementing the optimization recommendations. recommendations.