Fracturing degree and prediction of perforation cluster spacing for efficient exploitation of shale gas

The fracturing property of shale reservoirs is a key factor affecting shale gas production. Based on fracture mechanics theory, taking the shear failure of rock bedding weak plane under high confining pressure as the main research object, the concept of fracturing degree is proposed according to the ratio between tensile strength of rock and shear strength of bedding plane. The dimensionless qualitative curve is given, which covers the comprehensive geological and engineering factors of brittle mineral content, viscosity-dominated and toughness-dominated fracture tip fluid pressure and perforation cluster distribution spacing. Then, a new dimensionless parameter is proposed to characterize the fracturing degree of shale under high confining pressure, which can be used as a reference index for engineering. In this paper, fracture mechanics theory is combined with hydraulic fracturing for efficient shale gas production, which has mechanics theoretical significance and engineering application prospects. Copyright © 2022 Chinese Journal of Theoretical and Applied Mechanics. All rights reserved.