石油科学通报2025，Vol.10Issue(6)：1240-1251,12.DOI:10.3969/j.issn.2096-1693.2025.03.027
长宁五峰组页岩短期脆性蠕变变形与破坏机理研究
Mechanisms of short brittle creep deformation and failure of Wufeng shale in Changning
摘要
Abstract
To investigate the triaxial compression creep deformation behavior and failure mechanisms of shale,this study conducted stepwise incremental loading creep tests on Wufeng Formation shale of Changning under confining pressures of 10 MPa,30 MPa,and 50 MPa.The characteristics of axial,radial,and volumetric creep curves were analyzed.Combining computed tomography(CT)and scanning electron microscopy(SEM)techniques,the macroscopic and microscopic creep failure mechanisms of shale were systematically examined.A damage model was employed to fit and predict the long-term creep behavior of shale.The results indicate that:Volumetric creep effectively characterizes the evolutionary features of shale creep,with creep crack initiation stress and damage stress threshold corresponding to approximately 60%and 80%of peak strength,respectively.Shale creep failure is predominantly governed by microcrack initiation and coalescence,forming spatially distributed shear fracture networks characterized by shear-compaction bands and branched cracks.Multiple subparallel fractures develop within the shear-compaction bands,while extensive branching cracks readily form in surrounding regions.The damage model accurately predicts the long-term creep behavior of shale.Parameter A,associated with loading stress and elastic modulus,serves as the primary controlling factor for creep.This research can be applied to the analysis of the influence of shale creep on wellbore stability and artificial fracture closure during the drilling and fracturing processes of shale oil and gas reservoirs.关键词
页岩/蠕变机制/加速蠕变/剪切裂缝体/损伤模型Key words
shale/creep mechanism/accelerated creep/shear fracture network/damage model分类
能源科技引用本文复制引用
ZHOU Dawei,ZHANG Guangqing,LI Shiyuan,XU Quansheng,CAO Hu,ZHAO Chuyang,WANG Chen..长宁五峰组页岩短期脆性蠕变变形与破坏机理研究[J].石油科学通报,2025,10(6):1240-1251,12.基金项目
国家自然科学基金重点项目(52434001)、中国石油大学(北京)科研基金专项资金(ZX20230085)和国家自然科学基金面上项目(52274013)联合资助 （52434001）
