AirOil –An air injection screening study for improved

oil recovery from the Ekofisk field

byArvid Østhus, ConocoPhillips

Sigmund Stokka, RF – Rogaland Research

OutlineOutline

• Introduction to COREC – Center for oil recovery• Introduction to air injection• AirOil project plans• AirOil project results• Summary/conclusions

-- center for oil recoverycenter for oil recovery

Main objectives• The research work shall contribute to the national goal

of reaching an average recovery factor of 50 percent from oil reservoirs on the Norwegian continental shelf.

• The work shall support building and maintaining a strong national competence within improved oil recovery.

www.rf.no www.his.no

Preliminary COREC Master plan PL018Preliminary COREC Master plan PL018Phase 1 Technology qualificationsWater flooding characterisation and optimisation - Microscopic sweep - Macroscopic sweep - Cyclic water injectionWater based EOR techniques - Surfactant flooding - MEORGas based EOR techniques - CO2 injection - Air injection - Pressure depletion

�: Ranking of EOR processes

Phase 2 Field Pilot Pilot evaluation and planning

�: Decision point for pilotExecution and monitoringAnalysis of pilot results

Phase 3 Full Field ScaleFull Field planning and evaluation

�: Decision point for full field impl.Full field Implementation

Basic research2 and 3 phase flow WettabilityRock mechanicsRecovery mechanismsProfessor - Improved Recovery MethodsProfessor - Geomodelling

20122003 2004 2005 2006 20112007 2008 2009 2010

MotivationMotivation

Ekofisk Field: +1% incremental RF ~ 80 MMBOE

Air Injection into Light Oil ReservoirsAir Injection into Light Oil Reservoirs

Air Injection Oil Production

Zone swept by the oxidation front

Oxidation front250 to 300°C

Flue Gas drive at InitialReservoir Temperature

Oil and steam banks(thermal effects)

EU EU AirOilAirOil ProjectProject• The project is a major multi-partner effort sponsored by PL018 and EU.• Project start: August 2001.• Pilot initially planned Pilot in 2003 (postponed)• Main objectives:

→ Demonstrate AIROIL technology implementation offshore with zero-commercial-value IOR agent.

→ Demonstrate that a significant oil recovery increase can be achieved by applying AIROIL technology in the mature low permeability, fractured, light oil, chalk reservoirs.

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Air InjectionProduction

The AirOil ProjectThe AirOil Project

Industry Sponsor, PL018RF (Co-ord.)ConocoPhillipsPetecTotalIFPUBFabricom

EUSponsorContract

EUContract

AirOil Contractors

CooperationAgreement

SC

ConocoPhillipsTotalNorsk HydroEni NorgeStatoilPetoro

AirOilAirOil Project ScopeProject Scope

1. Field pilot screening RF

2. Supporting experiments RF

3. AirOil fractured reservoir simulator IFP

4. Downstream processing Fabricom

5. Field pilot design ConocoPhillips

6. Field pilot preparation, execution and evaluation ConocoPhillips

WP 1 WP 2

STATE – OF - THE - ART

4 WPWP 5

WP 6

WP3

Predictive tool Field pilot design DemonstrationField Pilot

AirAir--Oil Project:Oil Project:Major Decision PointsMajor Decision Points

WP1Field pilot screening

WP2Supporting experiments

WP3Modeling

WP4Downstream processing

WP5Field pilot design

WP6Field pilot implementation

DP1

WP - Work packageDP - Decision point

DP2

DP3

AFE approval to move into WP6

Project startedAugust 1, 2001

AirOilAirOil WP 2 WP 2 –– SupportingSupporting ExperimentsExperiments

Objectives

• To validate AIROIL process

• To evaluate the oxidation process and its effects at reservoir conditions, and gas flow in a 3D fractured medium

• To obtain quantitative data on reaction kinetics

• To calibrate predictive modelling tools

Experimental programme executed by:

• University of Bath

• Total

• ConocoPhillips

• RF – Rogaland Research

WP3 WP3 –– SimulationSimulation

• Simulation of laboratory experiments - IFP– The experiments are analysed and the Athos

simulator is tuned to fit with the experiments• Reaction kinetics• Diffusion

• Simulation at field scale – RF/Petec– Athos with tuned and upscaled parameters is

used in field simulation

AiroilAiroil Work Package 4, Work Package 4, FabricomFabricomDownstream ProcessingDownstream Processing

Objectives:� establish a technically, economically and environmentally feasible flue

gas handling system� estimate the cost for the flue gas handling system

Scope:� establish design criteria for flue gas handling system� review of gas handling scenarios� review of gas handling technology� select the most suitable gas handling technology� perform the Study for the flue gas handling system

AirAir--Oil Project:Oil Project:Major Decision PointsMajor Decision Points

WP1Field pilot screening

WP2Supporting experiments

WP3Modeling

WP4Downstream processing

WP5Field pilot design

WP6Field pilot implementation

DP1

WP - Work packageDP - Decision point

DP2

DP3

AFE approval to move into WP6

Summary/ConclusionsSummary/Conclusions

• performed studies of air injection kinetics and thermal effects in a light oil chalk reservoir

• performed studies of air injection flow/displacement mechanisms in a fractured chalk reservoir

• experienced significant experimental and modeling challenges (including up-scaling)

• performed screening evaluation of topside requirements• established a high quality international cross-disciplinary

group to study air injection issues• still, significant uncertainties and challenges are to be

resolved before a decision for field test can be made