Title: A proposed method for shale permeability tensor calculation considering shale anisotropy

Authors: Zengqiang Han; Shuangyuan Chen; Xiaokun Chen; Yiteng Wang; Shicong Huang; Dan Xu; Chao Wang

Addresses: Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China ' Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China ' Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China ' Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China ' Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China ' China Railway 11th Bureau Group Co. Ltd, Wuhan, 430061, China ' Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China

Abstract: As a common structure of sedimentary rock, bedding plane causes obvious anisotropy of shale permeability. Permeability is an important parameter for evaluating shale gas reservoirs, so it is necessary to study the percolation characteristics of shale under the influence of bedding plane. In this paper, permeability tests of different bedding angles, different confining pressure, and different percolation paths (axial//radial) were carried out on the shale specimens from the northern Guizhou Depression, China. Both axial and radial permeability tests method are based on pulse decay method. According to the test result, the influence mechanism of bedding plane on shale permeability is studied. The permeability of shale specimens decreases exponentially with the increase of confining pressure and angle of bedding direction. In addition, combined with the test results and percolation theory, a permeability tensor calculation method in shale reservoir is established. The permeability model of the measuring point is established by referring to the drill hole image data in the core well, which is presented in a spherical coordinate system. The permeability varies with the bedding angle in the shale reservoir are intuitively obtained. The results can provide reference for shale gas development and well layout. [Received: November 2, 2023; Accepted: August 24, 2024]

Keywords: anisotropic permeability; bedding plane; shale reservoir; tensor calculation method.

DOI: 10.1504/IJOGCT.2025.148038

International Journal of Oil, Gas and Coal Technology, 2025 Vol.38 No.2, pp.151 - 170

Received: 28 Oct 2023
Accepted: 24 Aug 2024
Published online: 15 Aug 2025 *

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