Experimental study on gas slippage of Marine Shale in Southern China

Abstract

The shale gas reservoirs are composed of porous media of different length scales such as nanopores, micropores, natural fractures and hydraulic fractures, which lead to high heterogeneity. Gas flow from pores to fractures is under different flow regimes and in the control of various flow mechanisms. The gas slippage would have significant effects on gas flow in shale. To obtain the effect of slippage on gas flow in matrix and fractures, contrast experiments were run by using cores with penetration fractures and no fractures from Marine Shale in Southern China under constant confining pressure. The results showed that slippage effect dominates and increases the gas permeability of cores without fractures. To cores with penetration fractures, slippage effect is associated with the closure degree of fractures. Slippage dominates when fractures close under low pore pressure. Slippage weakens due to the fractures opening under high pore pressure. Fracture opening reduces the seepage resistance and slippage effect. The Forchheimer effect occurs and leads to a permeability reduction.

Keywords

Shale gas / Permeability / Fracture / Slippage / Effective stress

Acknowledgments

We would like to thank the National “973” Plan Project of China (No. 2013CB228002) for providing financial support to this research work.

References

[1] A.S. Ziarani, R. Aguilera, Knudsen's permeability correction for tight porous media, Transp. Porous Med. 91 (1) (2011) 239-260.

[2] F.P. Wang, R.M. Reed, Pore networks and fluid flow in gas shales, in: SPE Annual Technical Conference and Exhibition, Society of Petroleum Engineers, 2009.

[3] F. Javadpour, D. Fisher, M. Unsworth, Nanoscale gas flow in shale gas sediments, J. Can. Pet. Technol. 46 (10) (2007) 55-61.

[4] C.H. Sondergeld, K.E. Newsham, J.T. Comisky, et al., Petrophysical considerations in evaluating and producing shale gas resources,in:SPE Unconventional Gas Conference, Society of Petroleum Engineers, 2010.

[5] N.G. Hadjiconstantinou, The limits of NaviereStokes theory and kinetic extensions for describing small-scale gaseous hydrodynamics, Phys. Fluids 18 (2006) 111301.

[6] S. Roya, R. Raju, H.F. Chuang, et al., Modeling gas flow through microchannels and nanopores, J. Appl. Phys. 93 (8) (2003) 4870-4879.

[7] F.A. Florence, J.A. Rushing, K.E. Newsham, et al., Improved permeability prediction relations for low permeability sands,in:Rocky Mountain Oil & Gas Technology Symposium, Society of Petroleum Engineers, 2007.

[8] Y. Ning, Y. Jiang, H. Liu, et al., Numerical modeling of slippage and adsorption effects on gas transport in shale formations using the lattice Boltzmann method, J. Nat. Gas Sci. Eng. 26 (2015) 345-355.

[9] L.J. Klinkenberg, The permeability of porous media to liquids and gases, in: API Drilling and Production Practice, American Petroleum Institute, 1941.

[10] J.G. Heid, J.J. Mcmahon, R.F. Nielsen, et al., Study of the permeability of rocks to homogeneous fluids, in: API Drilling and Production Practice, American Petroleum Institute, 1950.

[11] F.O. Jones, W.W. Owens, A laboratory study of low permeability gas sands, J. Pet. Technol. 32 (9) (1980) 1631-1640.

[12] K. Sampath, C.W. Keighin, Factors affecting gas slippage in tight sandstones, J. Pet. Technol. 34 (11) (1982) 2715-2720.

[13] F. Civan, C.S. Rai, C.H. Sondergeld, Shale-gas permeability and diffusivity inferred by improved formulation of relevant retention and transport mechanisms, Transp. Porous Med. 86 (3) (2011) 925-944.

[14] E.A. Letham, R.M. Bustin, Klinkenberg gas slippage measurements as a means for shale pore structure characterization, Geofluids 7 (2015) 1-5.

[15] G. Tang, W. Tao, Y. He, Gas slippage effect on microscale porous flow using the lattice Boltzmann method, Phys. Rev. E 72 (2005) 056301.

[16] G.Y. Zhu, L. Liu, Z.M. Yang, et al., Experiment and mathematical model of gas flow in low permeability porous media,in: New Trends in Fluid Mechanics Research, Springer, BerlineHeidelberg, 2009, p. 534.

[17] A. Beskok, G.E. Karniadakis, A model for flows in channels, pipes, and ducts at micro and nano scales, Microscale Thermophys. Eng. 3 (1) (1999) 43-77.

[18] E. Fathi, A. Tinni, I.Y. Akkutlu, Correction to Klinkenberg slip theory for gas flow in nano-capilaries, Int. J. Coal Geol. 103 (2012) 51-59.

[19] Y. Kang, M. Chen, X. Li, et al., Laboratory measurement and interpretation of nonlinear gas flow in shale, Int. J. Mod. Phys. 26 (6) (2015).

[20] R. Heller, J. Vermylen, M. Zoback, Experimental investigation of matrix permeability of gas shales, AAPG Bull. 98 (5) (2014) 975-995.

[21] W. Zhu, W. Tian, Y. Gao, et al., Study on experiment conditions of seepage law of marine shale gas, Nat. Gas Geosci. 26 (6) (2015) 1106-1112.

[22] Z. Yang, X. You, Z. Cui, et al. Pressure limit of slippage effect in low permeability tight gas reservoirs, J. Xian Shiyou Univ. (, Nat. Sci. Ed.) 30 (2015) 43-48.

[23] W.F. Brace, J.B. Walsh, W.T. Frangos, Permeability of granite under high pressure, J. Geophys. Res. 73 (1968) 2225-2236.

[24] X. Ren, A. Li, Y. Wang, et al., Gas permeability experimental study of low permeability core considering effect of gas slippage, Nat. Gas Geosci. 26 (4) (2015) 733-736.

[25] G. Zhu, X. Liu, S. Li, et al., A study of slippage effect of gas percolation in low permeability gas pools, Nat. Gas Ind. 27 (5) (2007) 44-47.