Analysis of Effective Porosity and Effective Permeability in Shale-Gas Reservoirs With Consideration of Gas Adsorption and Stress Effects
- Yu Pang (Texas Tech University) | Mohamed Y. Soliman (University of Houston) | Hucheng Deng (Chengdu University of Technology) | Hossein Emadi (Texas Tech University)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- July 2017
- Document Type
- Journal Paper
- 2017.Society of Petroleum Engineers
- adsorption, nanoscale, Effective porosity and permeability
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- 531 since 2007
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Nanoscale porosity and permeability play important roles in the characterization of shale-gas reservoirs and predicting shale-gas-production behavior. The gas adsorption and stress effects are two crucial parameters that should be considered in shale rocks. Although stress-dependent porosity and permeability models have been introduced and applied to calculate effective porosity and permeability, the adsorption effect specified as pore volume (PV) occupied by adsorbate is not properly accounted. Generally, gas adsorption results in significant reduction of nanoscale porosity and permeability in shale-gas reservoirs because the PV is occupied by layers of adsorbed-gas molecules.
In this paper, correlations of effective porosity and permeability with the consideration of combining effects of gas adsorption and stress are developed for shale. For the adsorption effect, methane-adsorption capacity of shale rocks is measured on five shale-core samples in the laboratory by use of the gravimetric method. Methane-adsorption capacity is evaluated through performing regression analysis on Gibbs adsorption data from experimental measurements by use of the modified Dubinin-Astakhov (D-A) equation (Sakurovs et al. 2007) under the supercritical condition, from which the density of adsorbate is found. In addition, the Gibbs adsorption data are converted to absolute adsorption data to determine the volume of adsorbate. Furthermore, the stress-dependent porosity and permeability are calculated by use of McKee correlations (McKee et al. 1988) with the experimentally measured constant pore compressibility by use of the nonadsorptive-gas-expansion method.
The developed correlations illustrating the changes in porosity and permeability with pore pressure in shale are similar to those produced by the Shi and Durucan model (2005), which represents the decline of porosity and permeability with the increase of pore pressure in the coalbed. The tendency of porosity and permeability change is the inverse of the common stress-dependent regulation that porosity and permeability increase with the increase of pore pressure. Here, the gas-adsorption effect has a larger influence on PV than stress effect does, which is because more gas is attempting to adsorb on the surface of the matrix as pore pressure increases. Furthermore, the developed correlations are added into a numerical-simulation model at field scale, which successfully matches production data from a horizontal well with multistage hydraulic fractures in the Barnett Shale reservoir. The simulation results note that without considering the effect of PV occupied by adsorbed gas, characterization of reservoir properties and prediction of gas production by history matching cannot be performed reliably.
The purpose of this study is to introduce a model to calculate the volume of the adsorbed phase through the adsorption isotherm and propose correlations of effective porosity and permeability in shale rocks, including the consideration of the effects of both gas adsorption and stress. In addition, practical application of the developed correlations to reservoir-simulation work might achieve an appropriate evaluation of effective porosity and permeability and provide an accurate estimation of gas production in shale-gas reservoirs.
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Ahmed, T. 2006. Reservoir Engineering Handbook. Houston: Gulf Professional Publishing.
Ambrose, R. J., Hartman, R. C., and Akkutlu, I. Y. 2011. Multi-Component Sorbed Phase Considerations for Shale Gas-In-Place Calculations. Presented at the SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 27–29 March. SPE-141416-MS. https://doi.org/10.2118/141416-MS.
Civan, F. 2013. Modeling Gas Flow Through Hydraulically-Fractured Shale-gas Reservoirs Involving Molecular-to-Inertial Transport Regimes and Threshold-Pressure Gradient. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, 30 September–2 October. SPE-166324-MS. https://doi.org/10.2118/166324-MS.
Clarkson, C. R. and Haghshenas, B. 2013. Modeling of Supercritical Fluid Adsorption on Organic-Rich Shales and Coal. Presented at the SPE Unconventional Resources Conference-USA, The Woodlands, Texas, 10–12 April. SPE-164532-MS. https://doi.org/10.2118/164532-MS.
Clarkson, C. R., Bustin, R., and Levy, J. 1997. Application of the Mono/Multilayer and Adsorption Potential Theories to Coal Methane Adsorption Isotherms at Elevated Temperature and Pressure. Carbon 35 (12): 1689–1705. https://doi.org/10.1016/S0008-6223(97)00124-3.
Cui, X., Bustin, A., and Bustin, R. M. 2009. Measurements of Gas Permeability and Diffusivity of Tight Reservoir Rocks: Different Approaches and Their Applications. Geofluids 9 (3): 208–223. https://doi.org/10.1111/j.1468-8123.2009.00244.x.
Dubinin, M. and Astakhov, V. 1971. Development of the Concepts of Volume Filling of Micropores in the Adsorption of Gases and Vapors by Microporous Adsorbents. Russ. Chem. B. 20 (1): 3–7. https://doi.org/10.1007/BF00849307.
Fan, D. and Ettehadtavakkol, A. 2016. Transient Shale Gas Flow Model. J. Nat. Gas Sci. Eng. 33 (July): 1353–1363. https://doi.org/10.1016/j.jngse.2016.04.007.
Grieser,W. V., Shelley, R. F., and Soliman, M. Y. 2009. Predicting Production Outcome FromMulti-stage, Horizontal Barnett Completions. Paper presented at the SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 4–8 April. SPE-120271-MS. https://doi.org/10.2118/120271-MS.
Gu, F. and Chalaturnyk, R. 2006. Numerical Simulation of Stress and Strain Due to Gas Sorption/Desorption and Their Effects on In Situ Permeability of Coalbeds. J Can Pet Technol 45 (10): 4–8. PETSOC-06-10-05. https://doi.org/10.2118/06-10-05.
Hartman, R. C., Ambrose, R. J., Akkutlu, I. Y. et al. 2011. Shale Gas-in-Place Calculations Part II - Multicomponent Gas Adsorption Effects. Presented at the North American Unconventional Gas Conference and Exhibition, The Woodlands, Texas, 14–16 June. SPE-144097-MS. https://doi.org/10.2118/144097-MS.
Huang, J. and Ghassemi, A. 2011. Poroelastic Analysis of Gas Production from Shale. Presented at the 45th US Rock Mechanics/Geomechanics Symposium, San Francisco, 26–29 June. ARMA-11-479.
Jarvie, D. M. 2012. Shale Resource Systems for Oil and Gas: Part 1–Shale-Gas Resource Systems. Tulsa: American Association of Petroleum Geologists.
Jin, Z. and Firoozabadi, A. 2016. Thermodynamic Modeling of Phase Behavior in Shale Media. SPE J. 21 (1): 190–207. SPE-176015-PA. https://doi.org/10.2118/176015-PA.
Lowell, S., Shields, J. E., Thomas, M. A. et al. 2012. Characterization of Porous Solids and Powders: Surface Area, Pore Size and Density, Vol. 16. Berlin: Springer Science & Business Media.
McKee, C. R., Bumb, A. C., and Koenig, R. A. 1988. Stress-Dependent Permeability and Porosity of Coal and Other Geologic Formations. SPE Form Eval 3 (1): 81–91. SPE-12858-PA. https://doi.org/10.2118/12858-PA.
Mengal, S. A. and Wattenbarger, R. A. 2011. Accounting For Adsorbed Gas in Shale Gas Reservoirs. Presented at the SPE Middle East Oil and Gas Show and Conference, Manama, Bahrain, 25–28 September. SPE-141085-MS. https://doi.org/10.2118/141085-MS.
Palmer, I. and Mansoori, J. 1996. How Permeability Depends on Stress and Pore Pressure in Coalbeds: A New Model. Presented at the SPE Annual Technical Conference and Exhibition, Denver, 6–9 October. SPE-36737-MS. https://doi.org/10.2118/36737-MS.
Peng, D. -Y. and Robinson, D. B. 1976. A New Two-Constant Equation of State. Industrial & Engineering Chemistry Fundamentals 15 (1): 59–64.
Pang, Y., Soliman, M. Y., Deng, H. et al. 2017. Experimental and Analytical Investigation of Adsorption Effects on Shale Gas Transport in Organic Nanopores. Fuel 199 (1 July): 272–288. https://doi.org/10.1016/j.fuel.2017.02.072.
Reyes, L. and Osisanya, S. 2000. Empirical Correlation of Effective Stress Dependent Shale Rock Properties. Presented at the Canadian International Petroleum Conference, Calgary, 4–8 June. PETSOC-2000-038. https://doi.org/10.2118/2000-038.
Ross, D. J. K. and Bustin, R. M. 2009. The Importance of Shale Composition and Pore Structure Upon Gas Storage Potential of Shale-Gas Reservoirs. Mar. Petrol. Geol. 26 (6): 916–927. https://doi.org/10.1016/j.marpetgeo.2008.06.004.
Sakurovs, R., Day, S., Weir, S. et al. 2007. Application of a Modified Dubinin_Radushkevich Equation to Adsorption of Gases by Coals under Supercritical Conditions. Energ. Fuel. 21 (2): 992–997. https://doi.org/10.1021/ef0600614.
Santos, J. M. and Akkutlu, I. Y. 2013. Laboratory Measurement of Sorption Isotherm under Confining Stress with Pore-Volume Effects. SPE J. 18 (5): 924–931. SPE-162595-PA. https://doi.org/10.2118/162595-PA.
Shi, J.-Q. and Durucan, S. 2005. A Model for Changes in Coalbed Permeability During Primary and Enhanced Methane Recovery. SPE Res Eval & Eng 8 (4): 291–299. SPE-87230-PA. https://doi.org/10.2118/87230-PA.
Sing, K. S. 1985. Reporting Physisorption Data for Gas/Solid Systems With Special Reference to the Determination of Surface Area and Porosity. Pure Appl. Chem. 57 (4): 603–619. https://doi.org/10.1515/iupac.54.0530.
Sondergeld, C. H., Newsham, K. E., Comisky, J. T. et al. 2010. Petrophysical Considerations in Evaluating and Producing Shale Gas Resources. Presented at the SPE Unconventional Gas Conference, Pittsburgh, Pennsylvania, 23–25 February. SPE-131768-MS. https://doi.org/10.2118/131768-MS.
Sudibandriyo, M., Pan, Z., Fitzgerald, J. E. et al. 2003. Adsorption of Methane, Nitrogen, Carbon Dioxide, and Their Binary Mixtures on Dry Activated Carbon at 318.2 K and Pressures up to 13.6 MPa. Langmuir 19 (13): 5323–5331. https://doi.org/10.1021/la020976k.
Sun, J., Hu, K., Wong, J. et al. 2014. Investigating the Effect of Improved Fracture Conductivity on Production Performance of Hydraulic Fractured Wells through Field Case Studies and Numerical Simulations. Presented at the SPE Hydrocarbon Economics and Evaluation Symposium, Houston, 19–20 May. SPE-169866-MS. https://doi.org/10.2118/169866-MS.
Wang, L., Metcalf, S. J., Critoph, R. E. et al. 2012. Development of Thermal Conductive Consolidated Activated Carbon for Adsorption Refrigeration. Carbon 50 (3): 977–986. https://doi.org/10.1016/j.carbon.2011.09.061.
Wu, F.-C., Wu, P.-H., Tseng, R.-L. et al. 2014. Description of Gas Adsorption Isotherms on Activated Carbons With Heterogeneous Micropores Using the Dubinin–Astakhov Equation. J. Taiwan Inst. Chem. Eng. 45 (4): 1757–1763. https://doi.org/10.1016/j.jtice.2014.01.016.
Yu, N., Wang, R., Lu, Z. et al. 2014. Development and Characterization of Silica Gel–LiCl Composite Sorbents for Thermal Energy Storage. Chem. Eng. Sci. 111 (24 May): 73–84. https://doi.org/10.1016/j.ces.2014.02.012.
Yu, W. and Sepehrnoori, K. 2014. Simulation of Gas Desorption and Geomechanics Effects for Unconventional Gas Reservoirs. Fuel 116 (15 January): 455–464. https://doi.org/10.1016/j.fuel.2013.08.032.