EGR With CO2 Sequestration

7/25/2019 EGR With CO2 Sequestration

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Presenter Biography Table of Contents IndexSession Q & A

Title: Enhanced Gas Recovery andCO2 Storage in Dry Gas Pools

Presented by: Alex Turta, Alberta Research Council
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Enhanced Gas Recovery (EGR)and CO2 Storage in Dry Gas Pools

Alex TurtaAshok Singhal

Steve Sim

CO2from Industrial Sources to Commercial

EOR RecoveryPTAC Workshop

October 1-2, 2003, Calgary


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Outline Background

CO2 use in Enhanced Gas Recovery(EGR) and CO2 storage

EGR field tests

Laboratory results (previous tests)

Further investigations


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EGR and CO2 Storage for DifferentGas Production Mechanisms

Depletion gas reservoirs: EGR and storageto be considered at an advanced stage of

depletion; with reservoir pressure increaseor at balanced injection/withdrawal

Water drive pools; dependency on stage ofexploitation is not so strong; balancedinjection/withdrawal can be an option


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The Case for EGR and CO2 Storage

Natural gas displacement by CO2 is miscible at any

pressure Mobility ratio CO2/ CH4 is always favorable,


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Objectives of our ResearchProject (under way)

To evaluate soundness of concept ofsimultaneous EGR and CO2 storage

and to identify the best strategy

To identify major Alberta dry gasreservoirs for EGR and CO2 storage


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CO2 mixtures for EGR andCO2 Storage

1) CO2 + CH42) CO2 + H2S / SO2 + N2 (acid gas)

3) CO2 + N2 (flue gas)4) pure CO2


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The results of this research project can beuseful in the following areas:

1. EGR by flooding with CO2 + CH4, CO2 +H2S/ SO2 and CO2 + N2 mixtures

2. Increased NGL recovery from gascondensate reservoirs

3. Underground gas storage (base gasreplacement; cushion gas)


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Why Mixtures of CO2 andMethane

Some gas plants/industrial CO2 streamscontain 10%-30% CH4

In reservoir, a partial separation of the twocomponents would occur due to differentsolubility in water

The produced original gas will becontaminated with the CH4 from theinjected mixture. Hence, higher gas recovery


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Why Acid Gases (AG)? Mixture of CO2 with H2S (non-incinerated AG) or

with SO2 and N2 - incinerated AG) Main characteristic: Injection into reservoir

producing sour gas; Gas inj rate


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Why Flue Gas (Mixtures ofCO2 and N2)

Large flue gas (FG) sources are located in thevicinity of major gas pools

CO2 separation cost is very high; our target is to

use the flue gas, as is. In principle, the recovery of one scf of natural gas

will require injection of one scf of flue gas

There are two solutions; either 1) use the FGalready available in the field/vicinity or 2)deliberately produce FG using some of the gas

recovered.


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Closed Loop Technology for EGR and CO2

Storage

GAS RESERVOIR

To

market8scf

9scf

Natural

Gas

Engine

1scf CH4

N2(air)-8scf Scrubbing,

Dehydration& Compression

9scf Flue gas

injection

Production

well

G

W

O2(air)-2scf

Cooling


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Advantage of Closed LoopTechnology for EGR and CO2 Total autonomy; EGR process does not depend on any

external source of flue gas; suitable for any location. 8 scf ofeach 9 scf gas recovered is sent to the market.

May be applied to water drive or depleted gas reservoirswith a high remaining OGIP value

Mainly an EGR technique, but it can be considered a CO2storage technique, when used in conjunction with heat co-

generation or generation of electricity; ZEPP.


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Summary of Previous Field Tests Underground gas storage

Cushion gas (base gas) practice

(N2 routinely used in France

- reservoir Saint-Claire-Sur

Epte)

EGR by CO2 flooding in

Budafa Szinfeletti Field,

Hungary: natural gas

recovery by injecting a mixture

of CO2 and CH4

Gas condensate reservoirsto minimize retrogradecondensation. Example:N2 injection for pressuremaintenance

Flue Gas (FG) injection

Miscible FG injection inBlock 31, Texas starting in1966. 24 injectors,Pi=28,000 kPa


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Budafa Szinfeletti Field: Injection of a

Mixture of 80%CO2 and 20% CH4(Erdol,Erdgas, Kohle)

Weak water drive gas reservoir Sandstone rock of 20% porosity and 5-40 mD

permeability; net pay thickness: 3 m

Initial reservoir pressure: 8850 kPa EGR and CO2 storage started when gas recovery

was 67% OGIP; (33% gas - not recovered), at a

pressure of 4500 kPa Incremental gas recovery: 11.6% OGIP (35%

recovery from the gas in place), in 8 years of

operation


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Methane recovery by CO2displacement. Laboratory tests1) US:

(Mamora, D. & Seo, J.: EGR by CO2 Sequestration

in Depleted Gas Reservoirs SPE Annual TechnicalMeeting, Houston, October, 2002)

Methane recovery at break-through (uncontaminated

methane recovery): 73-87%

2) Hungary:

Methane recovery at break-through: 70-90%


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Hypothetical Case Example: Depletion gas reservoir at the end of

exploitation, when gas recovery is 80% OGIP ;

remaining gas in place 20% OGIP

Assumption: 70% of remaining gas in place is

recovered by CO2 injection: 0.70 * 0.20 OGIP=0.14 (14% OGIP)

However, due to reservoir heterogeneity, therecovery by CO2 will be less than 14% OGIP

e.g. Hungarian field case: 11.6% OGIP


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IDEAL EGR Candidate Gas Reservoir

1. Heterogeneity (H) should be relatively low (mildH.), so that incremental gas recovery of un-contaminated natural gas is high

2.

Gravity stable or quasi-stable displacement shouldbe possible (high dip, high pay thickness, etc)

3. The number of wells to be utilized in EGR

operations is relatively high (at least 4-5)4. The storage effect is highest for certain

temperature and pressure conditions.


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Determination of Gas Reservoir

Heterogeneity Crucial for the Success ofEGR and CO2 Storage

Permeability heterogeneity from cores, as given byDykstra-Parsons coefficient (DPC)

DPC assessment based on depositional environment(PRIze procedure)

Tracer injection in the field (minimum two wells

necessary) Modified Fall-off Analysis after a period of gas

injection (similar to CBM procedure)


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Proof of Concept (laboratory work):Mixtures of CO2

Displacement of natural gas (with water saturation present)

using mixtures of CO2 + CH4, CO2 + SO2/H2S (acid gas), CO2+ N2 (flue gas) and pure N2 and CO2

Long cores; homogeneous and heterogeneous;diffusion/dispersion coefficient evaluation

Horizontal, vertical and tilted core displacements

Different pressures and temperatures


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Selection of Alberta Dry GasPools for EGR and CO2 Storage

Preliminary screening criteria have beenformulated

15 major gas pools to be selected; the longlist of 30 pools already exists

5 pools belonging to the participating

companies will be analyzed, and guidelinesfor CO2 EGR and CO2 storage will be

formulated for each pool.


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Main Parameters of the EGRDesign:

For the first set of EGR-CO2 storage gasreservoirs selected, the following parameterswill be determined:

- Duration of the project- Incremental gas recovery due to CO2/CH4 , CO2/ SO2

mixture injection, or due to FG injection

- Sales gas deliverability

- Cumulative CO2 injected/cumulative CO2 stored


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Classification of Gas Reservoirs

Water drive gas reservoirs; either edge water driveor bottom water drive; ultimate gas recovery=50%-60% original gas in place (OGIP). At

abandonment, high pressure and high gassaturation in water swept regions

Depletion gas reservoirs or closed pools; ultimate gasrecovery= 70%-85% OGIP. Relatively low pressureat abandonment.


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The Case for EGR and CO2Storage

Present concept: just storage of CO2 isconsidered after gas production reacheseconomic limit; no EGR considerations

We could consider: either only CO2 storageor EGR and CO2 storage


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Industrial CO2Mixture Sources Sweet gas processing plants (CO2%: 5-40)

Sour gas processing plants (CO2%: 25-95 andH2S%: 5-65)

Petrochemical plants (CO2%> 10) Pulp mines (CO2%: 10-20)

H2 plants, ethylene oxide plants andammonia plants (CO2%> 90)


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Better displacement efficiency whenusing a CO2 mixture (with methane)

In reservoir, a partial separation of the twocomponents would occur due to very differentsolubility in water

The produced original gas will be contaminatedwith the CH4 from the injected mixture. Hence,higher methane recovery

Other effects, such different diffusion/ dispersioncoefficients might have been important.

CO2Compressibility Factor; super-compressibili ty of CO2


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0 10 20 30 40 50 60 70

Pressure (MPa)

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Com

press

ilit

yF

ac

tor

55 0C 71

0

C

>150


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Presenter Biography Table of Contents IndexSession Q & A

End of Presentation
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EGR With CO2 Sequestration

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