Gas Miscibility and PVTPro

For Schlumberger Eureka Fluid Community Webinar, 2012

Jack Zhu

DBR Technology Center

Outlines

� EOR and Gas Miscibility

� Pseudo-Ternary Phase Diagram

� Lab EOR Tests

� PVTPro for Lab EOR Tests� PVTPro for Lab EOR Tests

� Conclusions

� Acknowledgments

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Introduction

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Enhance Oil Recovery

� 2/3 of OOIP remaining after primary recovery

� EOR technologies

� Chemical

� Thermal� Thermal

� Gas Injection

� 23% (89B bbl) of remaining oil can be

recovery by CO2 injection

Data based on research result of 10 US regions

Recent EOR Activities

Picture from :Has the time come for EOR? Schlumberger Oil Field Review

A Typical Gas Injection Process - WAG

Gas Injection Goal – Maximize Recovery Rate

� Rock Properties (Wettability)

� Miscible and Immiscible

– Ability of two or more substance to form a single homogeneous

phase when mixed in all proportions.(1)

– IFT=0 when Miscible, No interface between phases– IFT=0 when Miscible, No interface between phases

– First Contact Miscible

– Multi-Contact Miscible

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SPE 15794-PA, L.W. Holm, UNOCAL Corp

Miscible Type

� First Contact Miscible

– First contact miscible, any amount gas can be injected and will exist

as a single phase with oil in the reservoir.(C3,C4)

� Multi-Contact/Dynamic Miscible

– Vaporization, lean gas (C1,N2,CO2) travel through reservoir,

vaporizing C1 of RF and finally the leading edge miscible with virgin oil

– Condensation, rich gas (C2) travel through reservoir give up heavier

components to oil, when oil become sufficient enriched it is miscible

with fresh injecting gas.

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Gas Transition zone Oil

Vaporization MiscibleCondensation Miscible

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Pseudo-Ternary

Phase Diagram

Pseudo-Ternary Phase DiagramNo Component MW Reservoir Fluid CO2

49 lb/lbmol mole % mole %

1 CO2 44.01 2.658 100

2 H2S 34.08 0.845 0

3 N2 28.01 1.0951 0

4 C1 16.04 19.3153 0

5 C2 30.07 9.2759 0

6 C3 44.1 8.9181 0

7 i-C4 58.12 1.9731 0

8 n-C4 58.12 5.2932 0

9 i-C5 72.15 2.19 0

10 n-C5 72.15 2.834 0

11 C6 84 4.0079 0

12 Mcyclo-C5 84.16 0 0

13 Benzene 78.11 0 0

14 Cyclo-C6 84.16 0 0

15 C7 96 4.3189 0

16 Mcyclo-C6 98.19 0 0

17 Toluene 92.14 0 0

18 C8 107 4.6969 0

19 C2-Benzene 106.17 0 0

20 m&p-Xylene 106.17 0 0

21 o-Xylene 106.17 0 0

Reservoir Fluid CO2

Light Tc<=304.3 K 0.2307 1

Intermediate 304.3<Tc<=510.9 K 0.3534 0

Heavy Tc>510.9 K 0.4159 0

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21 o-Xylene 106.17 0 0

22 C9 121 4.1509 0

23 C10 134 3.6999 0

24 C11 147 3.009 0

25 C12 161 2.472 0

26 C13 175 2.131 0

27 C14 190 1.796 0

28 C15 206 1.762 0

29 C16 222 1.484 0

30 C17 237 1.21 0

31 C18 251 1.125 0

32 C19 263 1.06 0

33 C20 275 0.937 0

34 C21 291 0.843 0

35 C22 305 0.74 0

36 C23 318 0.616 0

37 C24 331 0.568 0

38 C25 345 0.502 0

39 C26 359 0.462 0

40 C27 374 0.434 0

41 C28 388 0.393 0

42 C29 402 0.369 0

43 C30 416 0.334 0

44 C31 430 0.296 0

45 C32 444 0.276 0

46 C33 458 0.248 0

47 C34 472 0.23 0

48 C35 486 0.209 0

49 C36+ 520 1.222 0

Phase Envelope in Ternary Diagram

Multi-contact Vaporization Miscible

Gas Transition zone Oil

Vaporization MiscibleCondensation Miscible

Multi-contact Condensation Miscible

Gas Transition zone Oil

Vaporization MiscibleCondensation Miscible

Make Gas Flooding Miscible – How?

Oil Composition

Gas Composition

Injection Pressure

Shrink

phase

Change gas position

in diagram

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Temperature

phase

envelope

Lab EOR Tests

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General Topics on Gas Miscibility

• Minimum Miscible Pressure Simulation (Vaporization/Condensation)

• Slimtube Test (MMP), Raising bubble

Pressure (MMP)

• Enrich the gas

• Minimum NGL Addition Calculation

Compositions (MMC)

• Minimum NGL Addition Calculation

• Slimtube Test (MMC)

• Multi-Contact Simulation (Vaporization/Condensation)

• Multi Contact Test (Vaporization/Condensation)

Miscibility Verification (Multiple-Contact)

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Slimtube Test For MMP or MMC

Change Pressure & Watch

Liquid Recovery

50 hours for each step (except

maintenance and calibration)

Slimtube MMP Determination

Multiple Contact Test

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19 hours for each contact

PVTPro for

Gas Miscibility

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Gas Miscibility

PVTPro Functions vs. Lab Jobs

PVTPro Function Description Lab Jobs

First Contact SolventSearch for minimum NGL

addition to dry gas

MMC/MMP SearchSearch for MMP or MMC

for 2 mechanisms

Slimtube test planning

Test result presentation

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MC Mixing & Flash

Gas and oil multiple contact

simulation for 2

mechanisms

Multiple contact test

planning

Test result presentation

Swelling CurveMixed property study with

various mixing ratiosSwelling test planning

� Example1: First Contact Solvent Search

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� Example 2: MMP Searching

Condensation MMP Result

Vaporization MMP Result

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Final Result =3499.3 psia

� MMP searching result will help to determine the pressure steps of slimtube test or

raising bubble test

� Example 3: Mixing and Flashing for Multiple Contact Test (Miscible)

� Ensure the results can be used to draw a proper ternary diagram

� Plan the solvent mixing ratio by simulation

� Test result explanation and presentation

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� Example 4: Mixing and Flashing for Multiple Contact Test (Immiscible)

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� Example 5: Multiple Contact Test Experimental Data Presentation

–Ternary Phase Diagram

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Conclusions

� Gas miscibility study plays an important role in EOR processes

� Ternary phase diagram is a useful tool in data interpretation

� PVTPro to be updated for Lab EOR tests � PVTPro to be updated for Lab EOR tests

� PVTPro with the enhanced module of gas miscibility will be available in

H1, 2012

� An evaluation license will be provided upon request to DBR Software

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Acknowledgment

� Jenna Na Jia

� Dan Zhang

� Julian Zuo

� Shu Pan

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Questions and Comments?

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