Method to Predict the Self-supporting Fracture Conductivity of Shale

doi:10.11885/j.issn.1674-5086.2019.03.27.05

Abstract

Abstract: The production capacity of shale gas wells primarily depends on the conductivity of the proppant filling layer fracture and the self-supporting fracture formed by the shear slip of the reservoir. Currently, our understanding of the variation law and mechanism that influences the self-supporting fracture conductivity of shale is insufficient. The fractal theory method was used to introduce the fractal dimensions of fracture aperture and tortuosity to characterize the fracture space quantitatively, and a mathematical model of self-supporting fracture conductivity was established that considers the effect of closure stress. An experiment of self-supporting fracture conductivity was conducted. The results show that the initial fracture conductivity reached 30~50 D·cm and could be maintained above 1 D·cm under a closure pressure of 40 MPa. The theoretical model prediction results agree well with the experimental test results. The sensitivity analysis shows that the fractal dimension of fracture aperture is positively correlated with the conductivity, while the fractal dimension of tortuosity is negatively correlated with the conductivity. The proposed method can quickly and accurately predict the self-supporting fracture conductivity of shale and provide support for rational prediction of gas well productivity.

Key words: fractal, conductivity, closure stress, shale gas, self-supporting fracture

CLC Number:

TE37

CAO Haitao, GUAN Xiaoxu, LI Xiaoping, ZHAO Yong, YU Xiaoqun. Method to Predict the Self-supporting Fracture Conductivity of Shale[J]. 西南石油大学学报(自然科学版), 2019, 41(5): 134-141.

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URL: http://journal15.magtechjournal.com/Jwk_xnzk/EN/10.11885/j.issn.1674-5086.2019.03.27.05

http://journal15.magtechjournal.com/Jwk_xnzk/EN/Y2019/V41/I5/134

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