shale extraction methods presentation

8/13/2019 Shale extraction Methods Presentation

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Copyright 2012 by Civan, Devegowda, and Sigal 1

Effective Shale

Gas and Condensate

Reservoir SimulationFaruk Civan, Deepak Devegowda, and Richard Sigal

Mewbourne School of Petroleum and GeologicalEngineering, University of OklahomaNorman, Oklahoma, U.S.A.


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Copyright 2012 by Civan,Devegowda, and Sigal

2

Acknowledgments

RPSEA

The University of Oklahoma SubcontractNo. 09122-11 (Sigal et al., 2010).

Consortium

Service and operating companies.


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3

Shale Gas and Condensate

Reservoirs

Exist throughout the world

Abundant source of hydrocarbons

Contain hydrocarbons and water Extremely low permeability

Hydraulically fractured to improve

production by creating Large fracture surface

Induced fractures


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Pore structure at different

scales

SEM imageInorganic poresOrganic poresThin cracks

Core plug Grid blockComplex matrixFractures

4 Faruk Civan, 2012

Adsorbed gas Free gas

Water

Modified after Passey et al.,2010.

Fracture


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5

Project Objectives

Critical Issues: What are different?

Theoretical Fundamentals Adequate Formulation

Validation using an in-house simulator

Implementation in commercial simulators Demonstration with applications


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Project Accomplishments

Most advanced transport equation

Non-Darcy flow under pore proximityeffects

Fully-coupled free and adsorptive phasetransport model

Multiple-porosity transport mechanisms Capillary relaxation coupled with relativepermeability modification


6


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Project Accomplishments

Handling various fracture systems by themethod of superposition

Upscaling from SEM to core and grid blocksizes

Fully-equipped one-dimensional testbench simulator in FORTRAN


7


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Work in Progress TOUGH2 Modification for shale reservoir

simulation

Properties of pore-confined fluids Molecular simulation

Thermodynamics and phase behavior

Permeability from drill-cuttings

Shale flow-units characterization

Comingled production analysis


8


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9

Shale Rock Composition

Complex shale matrix contains Inorganic materials

Clay minerals Nonclay minerals

Some organic matter called kerogen

Effective pore space contains Water

Clay bound water Capillary bound water Mobile water

Hydrocarbon Free gas Adsorbed gas Dissolved gas


Water

Modified after Passey etal., 2010, SPE 131350

Fracture


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10

Shale Rock Characteristics

Mud-rock Extremely low permeability around 100 nanodarcies (10-17m2) Complex pore structure contains

Intergranular porosity Intercrystalline matrix microporosity

Organic porosity Organic particles Thin cracks of

Natural types often cemented with some material Induced types created during hydraulic fracturing

Heterogeneous quad-media having different

Wettability Storage Transport Connectivity


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Quad-media Continuum

Transport with Six Exchange

Pathways

Faruk Civan, 2012 2

Inorganic

matter

Organic

matter

Natural

fracturesInduced

fractures


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12

Complex Issues of Gas and

Condensate Movement in Shale Heterogeneous quad-media system Each component has different wettability, storage,

transport, and connectivity

Hydrocarbons storage in different forms as the free gas,

adsorbed gas, and dissolved gas Alteration of fluid properties and behavior under pore

confinement

Gas transport by various mechanisms depending on

prevailing regimes Effective mean-radius and apparent permeabilitydepending on pore-size distribution and flow regime

Nonequilibrium fluid distribution in narrow flow paths.


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Gas Transport Mechanisms

13

Modified after(Bae and Do, 2005)

Adsorbed phase diffusion

Wall dominated gas flow

Gaseous viscous flow

As the tube size getssmaller, flow regime

changes to the point that

viscous (Darcy) flow

vanishes.

Faruk Civan, 2012


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Hydrocarbon Storage in Shale Pore-filling free gas

Dissolved gas in Organic matter

Water

Adsorbed and

condensed gases

Pore reduction effect Energy of surface of small pores is barelysufficient to hold only a monolayer

Langmuir adsorption isotherm is applied

q

p

L

L

q pqp p


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15

Gas Transport by Pressure

Reduction

Sequence of transport out of pores Free gas, first

Adsorbed gas, second

Dissolved gas, last Connectivity of quad-media

Strongly affects gas transfer

SEM images can only show micron scale connectivity

Practically inferred by Modeling

Production history matching

Faruk Civan, 2012 2

Inorganic

matter

Organic

matter

Natural

fracturesInduced

fractures


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Parameters of CapillaryGas Transfer

Rh Hydraulic radius Effective size parameter for non-

adsorbing gas at high pressure.l Mean-Free-Path

(For real gas lnot well understood)Kn= l/Rn Knudsen numberIn general porous media R

hdiffers from R

n

2h h

D Rl

Civan (2010)

Faruk Civan, 2012


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Flow classification and

modeling

17

Flow Regimes Models

Continuum flow

(Kn 0.001)

Euler equations

Bo

ltzmann

e

quation

No-slip Navier-

Stokes

equations

Slip flow

(0.001


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Copyright 2012 by Civan,Devegowda, and Sigal 18

Fluid Properties and Behavior

under Pore Confinement Pore size varies in 0.5-100 nm (Ambrose et

al.; Schulz and Horsfield, 2010). Light hydrocarbon molecule size varies in

0.40.6 nm (Mitariten, 2005).

Fluid properties and behavior in confinedpores deviate from large medium PVT cells Confinement effect

Promotes interactions between Pore surface and molecules Molecules themselves.

Results from various forces including van derWaals

Important when the pore-to-molecule size ratio isless than about 20 (Travalloni et al., 2010)


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Deviation From Normal Fluid

Behavior In Nanoporous Media

Occurs for Low pressure (Klinkenberg effect) Small pore size (pore proximity effect)

Pore proximity Dominant for high pressure reservoir fluidsApparent critical properties

Critical temperature deviation increases withincrease in molecule to pore size ratio But critical pressure deviation may increase or

decrease depending on pressure


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Effect of Confinement on Fluid

Property Modification

Pore reduction by surface retention Critical pressure and temperature

Real gas deviation factor

Density Real gas equation of state yields an apparent

gas density different than that measured in

unconfined medium.

Viscosity

Interfacial tension(IFT)


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Apparent Gas Critical

Properties

0.00

0.04

0.08

0.12

0.16

0.20

0 50 100 150 200

Tc

*=1-Tcp

/Tcb

Molecular Weight

5nm4nm

2nm

-0.5

-0.4-0.3

-0.2

-0.1

0.0

0.1

0.2

0.30.4

0 50 100 150 200

Pc

*=1-Pcp

/Pcb

Molecular Weight

5nm4nm

2nm

(Sapmanee, 2011)(Sapmanee, 2011)

Faruk Civan, 2012


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Effect of 2 nm pore on real gas

deviation factor

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

0 1000 2000 3000 4000 5000 6000

ZF

actor

Pressure [psia]

100 F (corrected)

150 F (corrected)

200 F (corrected)

250 F (corrected)

300 F (corrected)

100 F (uncorrected)

150 F (uncorrected)

200 F (uncorrected)

250 F (uncorrected)

300 F (uncorrected)

Temperature

Methane : 2nm

Michel G., Sigal R., Civan F.,Devegowda D. SPE 155787,

Copyright 2012, Society of

Petroleum Engineers


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Gas Viscosity Decreases With

Increasing Knudsen Number Kn

Gas viscosity (Beskok and Karniadakis,1999)

Rarefaction coefficient (Civan, 2010):

1and lim 0

1 KnKn

1 and limo

oBKn

A

Kn


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Rarefaction Coefficientaccounts for all regimes

24

-7.5

-7.0

-6.5

-6.0

-5.5

-0.2 0.0 0.2 0.4 0.6 0.8

log(Viscosity,Pa.s)

log (Nanotube Radius, nm)

Chen et al.(2008)

Beskok and

Karniadakis (1999)1

1

Rarefaction coefficient

Civan, 2010

1

o

B

Kn

A

Kn

Faruk Civan, 2012

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.E-09 1.E-05 1.E-011.E+03

Dimensionless

rarefaction

coefficie

nt,

Knudsen number, Kn

Loyalka andHamoodi (1990)Civan (2010)

Civan, 2011


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Apparent Gas-condensate IFT

c: empirical constant

Dp: mean-pore diameterSG: gas saturation.Modified after Hamada et al. (2007)

and Sapmanee (2011)

1 2

limp

p G

D

cD S

Gas

DG= D

P

2

4AL

SL=A

L

AP

=A

L

AG+

AL


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Flow Through Porous Media

26

aK A pqL

L

1

2

3

4

5

6

7

0 1 2 3 4 5 6 7 8 9 10

K/K0

Reciprical of Pressure [10-3

psia-1

]

Methane : T = 170 F

median = 34

median = 56

median = 152

Klinkenberg predictslinear trend

Cannot describetransition and free-molecular flow

Michel et al (2011)

Faruk Civan, 2012

A t P bilit


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Apparent Permeability

Correction Factor

27

4

( ) 1 11

Knf Kn Kn

bKn

(Beskok andKarniadakis,1999)

1

10

100

1000

10000

0.01 0.1 1 10 100 1000

Permeab

ilitycorrection

factor,

f(Kn)=Ka/K,

dimensionless

Knudsen number, Kn,

dimensionless

( )aK f KnK

Civan (2010)

Faruk Civan, 2012

C ti f P i


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Correction for Pore-size

Distribution Effect

Range representative ofnanoporous shale

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1 10 100 1000 10000

DensityProb

ability

Radius []

median = 152

median = 56

median = 34

1

10

100

14.5 145 1450 14500

K/K0

Pressure [psia]

Methane : T = 170 F

r = 50

r = 100

r = 500

r = 1000

r = 5000

median = 152

median = 56

median = 34

(Michel et al.,2011)

(Michel et al.,2011)

Faruk Civan, 2012

Eff ti H d li


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Effective vs. Hydraulic

Mean-Radii

Hydraulic radius, Rh(Intrinsic permeability)

Effective radius, Re

(Apparent permeability)

8h

KR

-

-

-

-

4

0

4

0

4

4( )

8

( )

8

ee R e

e e

R R b

R R b

r r br f r dr

r r b

rf r d r

l l

l

l l

l

0

500

1000

1500

0 500 1000 1500Effectiveradius,A,Re

Hydraulic radius, A, Rh

N: Number of tubes

f(r): pore size distribution

(Michel etal., 2011)

Faruk Civan, 2012


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Spontaneous Hydraulic Fluid

Spreading

Significant portion of injected fluiddoes not return to surface duringclean-up

Accurate prediction of fracturing-fluidspreading is important.

30


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Hydraulic Fracturing Fluid

Entrapment Equilibrium state is not reached

after many months of production.

Pressure trends indicate waterentrapment in narrow capillaries.

Trapped water may invade deepinto formation by imbibition.

Assuming instantaneous fluidadvance predicts unrealisticnegative capillary pressure.

31

N ilib i fl id


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Nonequilibrium fluid

distribution effect

Narrow flow paths

require long time toattain equilibrium

fluid redistribution

32

Tortuousnarrowflow path

, ,

,

e

SS S X S

t

S SS g S

t t

(Hassanizadeh and Gray,1993; Barenblatt et al., 2003)

S

Se

Time(0, 0)

: Relaxation time

Faruk Civan, 2012


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Nonequilibrium Fluid

Distribution in Narrow Paths

Seq: equilibrium fluid saturation

S: instantaneous nonequilibrium fluid saturation S

: relaxation time

t : real time

eq

SS S

t

(Hassanizadeh and Gray,1993; Barenblatt et al., 2003)

E ilib i N ilib i


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Equilibrium vs. Nonequilibrium

Saturation

34

0

0.25

0.5

0.75

0 0.25 0.5 0.75 1

Pc[atm]

Wetting phasesaturation

Equilibrium

Nonequilibrium

e

SS S

t

(Andrade, 2011)

Faruk Civan, 2012


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Gas Water flow by apparentvs. Darcy Formulation

35

Gas Displacing Water (Andrade, 2011)

Faruk Civan, 2012



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scales

SEM imageInorganic poresOrganic poresThin cracks

Core plug Grid blockComplex matrixFractures

36

Faruk Civan, 2012


Water

Modified after Passey et al.,

2010.

Fracture


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Upscaling for Effective Shale

Reservoir Scale Simulation

Integrate various features of shale at different scales From the SEM grain scale To the representative elementary volume Then to gigantic reservoir grid block size

Relate permeability of percolating network of differentcharacteristics to an effective medium description

Apply superposition of porosity and permeability of Background interconnected and dead-end pores of matrix

Thin sheet shaped cracks formed over the interparticle poresystem, acting like the pore throats.

Q d di C ti


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Quad-media Continuum

Transport With Source/Sink

( ) .( )

( ). . ( )

( )

.

1and

a

a

T

T

qt

ww w qw

t

Kp

K

p qt

Mpc

ZRT p

u

u D

u

Faruk Civan, 2012 2

Inorganicmatter

Organicmatter

Natural

fracturesInduced

fractures

Civan et al. (2012)


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Effective transport and productive capability

Quad-Porosity effective medium grid blockproperties

Matching grid block response generated byfine-grid simulation

Grouping into quad-porosity effective media Match production time dependence of fine-grid

model

Allow up to four conductors with differentproperties

Source terms to handle sorbed gas Both single and dual media treatments can

be implemented with present commercialsimulators (Hudson et al. 2012).


39

Upscaling Methodology

Homogenouseffectiveblock

Fine-grid

Upscaling

Recovery Factor by Tank Model


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Recovery Factor by Tank Model

of Quad-porosity System


Hudson et al. (2012)Copyright 2012, Society ofPetroleum Engineers


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Final Remarks

Quad-media shale pore structure andcharacteristics

Alteration of fluid and pore properties

and behavior Fundamental gas transfer mechanisms Nonequilibrium fluid distribution

Modeling considerations for effectivesimulation of shale gas and condensatereservoirs.


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References Andrade, Juan Felipe, One Dimensional Test Bed Incorporating Correct Physics Of Fluid

Redistribution And Transport For Simulation Of Shale-Gas Reservoirs, M.S. thesis, U. ofOklahoma, May 2011.

Andrade, J., Civan, F., Devegowda, D., and Sigal, R., Accurate Simulation of Shale-GasReservoirs, Paper SPE 35564-PP, the SPE Annual Technical Conference and ExhibitionFlorence, Italy, 1922 September 2010.

Andrade J., Civan, F., Devegowda, D., and Sigal, R. Design Requirements for a Shale GasReservoir Simulator and an Examination of How the Requirements Compare to Designs of

Current Shale Gas Simulators, Paper SPE-144401, the SPE Americas Unconventional GasConference, 14-16 June 2011 in The Woodlands, Texas.

Ambrose, R.J., Hartman, R.C., Campos, M.D., Akkutlu, I.Y. and Sondergeld, C. 2010. New Pore-scale Considerations for Shale Gas in Place Calculations. Paper SPE 131772-MS presented atthe SPE Unconventional Gas Conference, Pittsburgh, Pennsylvania, USA, 02/23/2010. doi:10.2118/131772-MS.

Bae, J.-S. and Do, D.D., Permeability of Subcritical Hydrocarbons in Activated Carbon, AIChE

J., 51(2), pp. 487-501, 2005. Barenblatt, G.I., Patzek, T.W. and Silin, D.B. 2003. The Mathematical Model of Nonequilibrium

Effects in Water-Oil Displacement. SPE Journal, Vol.8 (4): 409-416. SPE 87329-PA. doi:10.2118/87329-PA.


42


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References

Beskok, A. and Karniadakis, G.E.:A model for flows in channels, pipes, and ducts at micro andnano scales, Microscale Thermophysical Engineering Vol. 3 No. 1 pp. 43-77 (1999).

Chen, X., Cao, G., Han, A., Punyamurtula, V.K., Liu, L., Culligan, P.J., Kim, T. and Qiao, Y. 2008.Nanoscale Fluid Transport: Size and Rate Effects, Nano Letter8(9): 2988-2992.

Civan, F. 2002. A Triple-Mechanism Fractal Model With Hydraulic Dispersion For Gas Permeationin Tight Reservoirs. Paper 74368 presented at the SPE International Petroleum Conference andExhibition in Mexico, Villahermosa, Mexico, 01/01/2002. doi: 10.2118/74368.

Civan, F.: Effective Correlation of Apparent Gas Permeability in Tight Porous Media, Transport inPorous Media, Vol. 82, No. 2, pp. 375-384, 2010.

Civan, F., A Review of Approaches for Describing Gas Transfer Through Extremely Tight PorousMedia, Porous Media and Its Applications in Science, Engineering, and Industry, Vafai, K. (ed.),Proceedings of the Third ECI International Conference on Porous Media and its Applications inScience, Engineering and Industry, June 20-25, 2010, Montecatini Terme, Italy, pp. 53-58, 2010.

Civan, F., Correlate Data Effectively, Chemical Engineering Progress, Vol. 107, No. 2, pp. 35-44,

February 2011. Civan, F., Devegowda, D., and Sigal, R. F., Theoretical Fundamentals, Critical Issues, andAdequate Formulation of Effective Shale Gas and Condensate Reservoir Simulation, PorousMedia and Its Applications in Science, Engineering, and Industry, Vafai, K. (ed.), Proceedings(CD) of the 4th International Conference on Porous Media and its Applications in Science andEngineering, ICPM4, pp. 155-160, June 17-22, 2012, Potsdam, Germany.


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References Hamada, Y., Koga, K. and Tanaka, H. 2007. Phase equilibria and interfacial tension of fluids

confined in narrow pores, J. Chem Phys127(8): 084908-1- 084908-9.

Hassanizadeh SM and Gray WG. Thermodynamic of capillary pressure in porous media. WaterResources Research. 1993; 29: 3389-3405.

Hudson, John D., Quad-Porosity Model for Description of Gas Transport in Shale-GasReservoirs, M.S. thesis, U. of Oklahoma, December, 2011.

Hudson, J., Civan, F., Michel, G., Devegowda, D., and Sigal, R., "Modeling Multiple-PorosityTransport in Gas-Bearing Shale Formations," Paper SPE-153535-PP,the 2012 SPE Latin America

and the Caribbean Petroleum Engineering Conference, 16-18 April 2012 in Mexico City, Mexico. Hudson, J.D., Michel, G. G., Civan, F., Devegowda, D., Sigal, R. F. Modeling Multiple-PorosityTransport in Gas-Bearing Shale Formations. Paper SPE 153535, SPE Annual TechnicalConference and Exhibition, SanAntonio, TX, 4-7 Oct 2012.

Loyalka, S.K. and Hamoodi, S.A.: Poiseuille Flow of a Rarefied Gas in a Cylindrical Tube: Solutionof Linearized Boltzmann Equation, Phys. Fluids A, Vol. 2, No. 11, pp. 2061-2065 (1990).

Michel, G., Sigal, R. F., Civan, F., and Devegowda, D., Proper Modeling of Nano-Scale Real-Gas

Flow Through Extremely Low-Permeability Porous Media under Elevated Pressure andTemperature Conditions, 7th International Conference on Computational Heat and MassTransfer, stanbul, Turkey, 18-22 July, 2011.


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http://www.spe.org/atce/2012/http://www.spe.org/atce/2012/http://www.spe.org/atce/2012/http://www.icchmt.com/http://www.icchmt.com/http://www.icchmt.com/http://www.icchmt.com/http://www.spe.org/atce/2012/http://www.spe.org/atce/2012/http://www.spe.org/atce/2012/


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References Michel, G., Civan, F., Sigal, R. F., and Devegowda, D., "Parametric Investigation of Shale Gas

Production Considering Nano-Scale Pore Size Distribution, Formation Factor, and Non-DarcyFlow Mechanisms," SPE-147438-PP, the 2011 SPE Annual Technical Conference and Exhibition(ATCE), 30 October 2 November 2011 in Denver, Colorado.

Michel, G., Civan, F., Sigal, R. F., and Devegowda, D., "Effect of Capillary Relaxation on WaterEntrapment After Hydraulic Fracturing Stimulation," Paper SPE-155787-PP, the 2012 AmericasUnconventional Resources Conference held 5-7 June at the David L. Lawrence ConventionCenter in Pittsburgh, Pennsylvania, USA.

Mitariten, M. 2005. Molecular gate adsorption system for the removal of Carbon dioxide and/orNitrogen from coalbed and coal mine Methane, presented at 2005 Western States Coal MineMethane Recovery and Use Workshop, Two Rivers Convention Center, Grand Junction, CO, April1920.

Passey, Q.R., Bohacs, K., Esch, W.L., Klimentidis, R. and Sinha, S. 2010. From Oil-Prone SourceRock to Gas-Producing Shale Reservoir - Geologic and Petrophysical Characterization ofUnconventional Shale Gas Reservoirs. Paper SPE presented at the International Oil and GasConference and Exhibition in China, Beijing, China, 06/08/2010.

Sapmanee, K., Effects of Pore Proximity on Behavior and Production Prediction ofGas/Condensate, M.S. thesis, U. of Oklahoma, September 2011.


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References

Sapmanee, K, Devegowda, D., Civan, F. and Sigal, R.F. Phase Behavior of Gas Condensates inShales Due to Pore Proximity Effects: Implications for Transport, Reserves and Well Productivity,Paper SPE 160099, SPE Annual Technical Conference and Exhibition, SanAntonio, TX, 4-7 Oct2012.

Schaaf , S.A. and Chambre, P.L., Flow of Rarefied Gases, Princeton University Press, Princeton,New Jersey (1961).

Schulz, H.M. and Horsfield, B., Rock matrix as reservoir: mineralogy & diagenesis Deutsches

GeoForschungs ZentrumGFZ, Potsdam, University of Cape Town, Rondebosch 7701, SouthAfrica, 2010.

Sigal, R., Devegowda, D., and Civan, F., RFP 2009UN001, Simulation of Shale Gas ReservoirsIncorporating Appropriate Pore Geometry and the Correct Physics of Capillarity and FluidTransport, $1.3 Millions, funded by PRSEA, October 1, 2010-2012.

Travalloni, L., Castier, M., Tavares, F.W. and Sandler, S.I. 2010. Critical behavior of pure confinedfluids from an extension of the van der Waals equation of state. The Journal of Supercritical

Fluids, Vol.55 (2): 455-461. Xiong, X., Devegowda, D., Civan, F., Michel, G. G., and Sigal, R.F., A Fully-Coupled Free and

Adsorptive Phase Transport Model for Shale Gas Reservoirs Including Non-Darcy Flow Effects,Paper SPE 159758, SPE Annual Technical Conference and Exhibition, SanAntonio, TX, 4-7 Oct2012.

Copyright 2012 by Civan, 46
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