Experimental and numerical simulation of water adsorption and diffusion in shale gas reservoir rocks
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Abstract
Despite the success of deep horizontal drilling and hydraulic fracturing in yielding large production increases from unconventional shale gas reservoirs, uncertainties associated with basic transport processes require understanding in order to improve efficiency and minimize environmental impacts. The hydraulic fracturing process introduces large volumes of water into shale gas reservoirs, most of which remains unrecoverable and interferes with gas production. In this study, the water adsorption and diffusion measurements of the Longmaxi Formation shale were conducted at 30℃ and 50℃for relative humidities from 11.1% to 97.0%. Based on the experiment, a computational model based on the Maxwell-Stefan diffusion equation was constructed to analyze water adsorption and diffusion in shale rocks, and the Guggenheim-Anderson-de Boer (GAB) isotherm for gas adsorption was included in the model. The results show that water adsorption isotherms of shales belong to type II curve, including the monolayer, multilayer adsorption and capillary condensation, and the GAB model can be used to describe the water adsorption process in shale rocks. With the increasing of relative pressure, the water adsorption of shale increases, and the organic carbon content and temperature strengthen the water adsorption in shale. The capillary pressure can reach the order of several hundreds of MPa after the hydraulic fracturing process, and it results in a large amount of fracturing fluid retained in shale gas reservoirs. Furthermore, the simulations of water adsorption and diffusion in shale rocks is less than the experimental value, which further indicates that capillary condensation occurs in shale rocks.
Cited as: Shen, W., Li, X., Cihan, A., Lu, X., Liu, X. Experimental and numerical simulation of water adsorption and diffusion in shale gas reservoir rocks. Advances in Geo-Energy Research, 2019, 3(2): 165-174, doi: 10.26804/ager.2019.02.06
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Adamson, A.W., Gast, A.P. Physical Chemistry of Surfaces. New York, USA, John Wiley & Sons, 1967.
Ai-Awad, M.N.J., Smart, B.G.D. Characterization of shale-drilling fluid interaction mechanisms related to wellbore instability. J. King Saud Univ. Eng. Sci. 1996, 8(2): 187-214.
Anderson, R.B. Modifications of the Brunauer, Emmett, and Teller equation. J. Am. Chem. Soc. 1946, 68(4): 686-691.
Boer, J.H. The Dynamic Character of Adsorption. Oxford, UK, Clarendon Press, 1953.
Chang, M., Zhou, J., Chenevert, M.E., et al. The impact of shale preservation on the petrophysical properties of organic-rich shales. Paper SPE166419 Presented at SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 30 September-2 October, 2013.
Chenevert, M.E. Shale control with balanced-activity oil-continuous muds. J. Pet. Technol. 1970, 22(10): 1309-1316.
Chenevert, M.E., Pernot, V. Control of shale swelling pressures using inhibitive water-base muds. Paper SPE49263 Presented at SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 27-30 September, 1998.
Cheng, Y. Impact of water dynamics in fractures on the performance of hydraulically fractured wells in gas shale reservoirs. J. Can. Pet. Technol. 2012, 51(2): 143-151.
COMSOL. Sweden, COMSOL Inc., 2015.
Dehghanpour, H., Lan, Q., Saeed, Y., et al. Spontaneous imbibition of brine and oil in gas shales: Effect of water adsorption and resulting microfractures. Energy Fuels 2013, 27(6): 3039-3049.
Foo, K.Y., Hameed, B.H. Insights into the modeling of adsorption isotherm systems. Chem. Eng. J. 2010, 156(1): 2-10.
Frenkel, J. Kinetic Theory of Liquids. Oxford, UK, Oxford University Press, 1946.
Gao, S., Hu, Z., Guo, W., et al. Water absorption characteristics of gas shale and the fracturing fluid flowback capacity. Natural Gas Industry 2013, 33(12): 71-76. (in Chinese)
Ge, H., Yang, L., Shen, Y., et al. Experimental investigation of shale imbibition capacity and the factors influencing loss of hydraulic fracturing fluids. Pet. Sci. 2015, 12(4): 636-650.
Genuchten, M.T.V. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 1980, 44(5): 892-898.
Greenspan, L. Humidity fixed-points of binary saturated aqueous solutions. J. Res. Nat. Bur. Stand. Sect. A 1977, 81(1): 89-96.
Guggenheim, E.A. Application of Statistical Mechanics. Oxford, UK, Clarendon Press, 1966.
Halsey, G.D.J. Physical adsorption on non-uniform surfaces. J. Chem. Phys. 1948, 16(10): 931-937.
Hill, T.L. Advances in catalysis. J. Chem. Phys. 1949, 17: 580-668.
International Energy Agency. World Energy Outlook 2018.
Paris, IEA/OECD, 2018.
King, G.E. Thirty years of gas shale fracturing: What have we learned? Paper SPE 133456 Presented at SPE Annual Technical Conference and Exhibition, Florence, Italy, 19-22 September, 2010.
Li, J., Li, X., Wu, K., et al. Thickness and stability of water film confined inside nanoslits and nanocapillaries of shale and clay. Int. J. Coal Geol. 2017, 179: 253-268.
Li, Q., Xing, H., Liu, J., et al. A review on hydraulic fracturing of unconventional reservoir. Petroleum 2015, 1(1): 8-15.
Makhanov, K., Habibi, A., Dehghanpour, H., et al. Liquid uptake of gas shales: A workflow to estimate water loss during shut-in periods after fracturing operations. J. Unconv. Oil Gas Res. 2014, 7: 22-32.
Odusina, E.O., Sondergeld, C.H., Rai, C.S. An NMR study of shale wettability. Paper SPE 147371 Presented at SPE Canadian Unconventional Resources Conference, Calgary, Alberta, Canada, 15-17 November, 2011.
Prost, R., Benchara, A., Huard, E. State and location of water adsorbed on clay minerals: Consequences of the hydration and swelling-shrinkage phenomena. Clays Clay Miner. 1998, 46 (2): 117-131.
Qi, R., Ning, Z., Wang, Q., et al. Sorption measurements of moistureequilibrated shale with the consideration of water vapor pressure. Sci. Sin. 2018, 48(5): 524-536.
Shang, S., Horne, R.N., Jr, H.J.R. Water vapor adsorption on geothermal reservoir rocks. Geothermics 1995, 24(4): 523-540.
Shen, W., Li, X., Lu, X., et al. Experimental study and isotherm models of water vapor adsorption in shale rocks. J. Nat. Gas Sci. Eng. 2018, 52: 484-491.
Shen, W., Li, X., Xu, Y., et al. Gas flow behavior of nanoscale pores in shale gas reservoirs. Energies 2017, 10(6): 1-12.
Shen, W., Xu, Y., Li, X., et al. Numerical simulation of gas and water flow mechanism in hydraulically fractured shale gas reservoirs. J. Nat. Gas Sci. Eng. 2016, 35: 726-735.
Shen, W., Zheng, L., Oldenburg, C.M., et al. Methane diffusion and adsorption in shale rocks: A numerical study using the dusty gas model in Tough2/EOS7C-ECBM. Transp. Porous Media 2018, 123(3): 521-531.
Shen, Y., Ge, H., Su, S., et al. Imbibition characteristic of shale gas formation and water-block removal capability. Sci. Sin-Phys. Mech. Astron. 2017, 47: 114609.
Tandanand, S. Moisture adsorption rate and strength degrada-tion of Illinois shales. Paper ARMA-85-0591-1 Presented at The 26th U.S. Symposium on Rock Mechanics (USRMS), Rapid City, South Dakota, 26-28 June, 1985.
Tien, C. Adsorption Calculations and Modeling. Boston, USA, Butterworth-Heinemann, 1994.
Tokunaga, T.K., Shen, W., Wan, J., et al. Water saturation relations and their diffusion-limited equilibration in gas shale: Implications for gas flow in unconventional reservoirs. Water Resour. Res. 2017, 53(11): 9757-9770.
Wei, M., Duan, Y., Fang, Q., et al. Mechanism model for shale gas transport considering diffusion, adsorption/desorption and Darcy flow. J. Cent. South Univ. 2013, 20(7): 1928-1937.
Wei, M., Duan, Y., Fang, Q., et al. Production decline analysis for a multi-fractured horizontal well considering elliptical reservoir stimulated volumes in shale gas reservoirs. J. Geophys. Eng. 2016, 13(3): 354-365.
Wu, Q., Bai, B., Ma, Y., et al. Optic imaging of two-phase-flow behavior in 1D nanoscale channels. SPE J. 2014, 19(5): 793-802.
Xu, J., Guo, C., Wei, M., et al. Production performance analysis for composite shale gas reservoir considering multiple transport mechanisms. J. Nat. Gas Sci. Eng. 2015, 26: 382-395.
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