Microstructural evolution and hydraulic response of shale self-propped fracture using X-ray computed tomography and digital volume correlation  

作　　者：Ting Huang Cheng Zhai Ting Liu Yong Sun Hexiang Xu Yu Wang Jing Huang 

机构地区：[1]State Key Laboratory of Coal Mine Disaster Prevention and Control,Ministry of Education,China University of Mining and Technology,Xuzhou 221116,China [2]Key Laboratory of Theory and Technology on Coal and Rock Dynamic Disaster Prevention and Control,National Mine Safety Administration,China University of Mining and Technology,Xuzhou 221116,China [3]School of Safety Engineering,China University of Mining and Technology,Xuzhou 221116,China [4]School of Low-Carbon Energy and Power Engineering,China University of Mining and Technology,Xuzhou 221116,China

出　　处：《International Journal of Mining Science and Technology》2025年第3期345-362,共18页矿业科学技术学报(英文版)

基　　金：financially supported by the National Key Research and Development Program of China (No.2020YFA0711800);the National Science Fund for Distinguished Young Scholars (No.51925404);the Graduate Innovation Program of China University of Mining and Technology (No.2023WLKXJ149);the Fundamental Research Funds for the Central Universities (No.2023XSCX040);the Postgraduate Research Practice Innovation Program of Jiangsu Province (No.KYCX23_2864)。

摘　　要：Methane in-situ explosive fracturing technology produces shale debris particles within fracture channels,enabling a self-propping effect that enhances the fracture network conductivity and long-term stability.This study employs X-ray computed tomography(CT)and digital volume correlation(DVC)to investigate the microstructural evolution and hydromechanical responses of shale self-propped fracture under varying confining pressures,highlighting the critical role of shale particles in maintaining fracture conductivity.Results indicate that the fracture aperture in the self-propped sample is significantly larger than in the unpropped sample throughout the loading process,with shale particles tending to crush rather than embedded into the matrix,thus maintaining flow pathways.As confining pressure increases,contact areas between fracture surfaces and particles expand,enhancing the system's stability and compressive resistance.Geometric analyses show flow paths becoming increasingly concentrated and branched under high stress.This resulted in a significant reduction in connectivity,restricting fracture permeability and amplifying the nonlinear gas flow behavior.This study introduces a permeability-strain recovery zone and a novel sensitivity parameter m,delineating stress sensitivity boundaries for permeability and normal strain,with m-value increasing with stress,revealing four characteristic regions.These findings offer theoretical support for optimizing fracturing techniques to enhance resource extraction efficiency.

关 键 词：Digital volume correlation X-ray CT scanning Fracture aperture Deformation characteristics Stress sensitivity Permeability 

分 类 号：TG1[金属学及工艺—金属学]