CO_(2)作用下页岩力学特性及破坏行为  

Mechanical Properties and Failure Behavior of Shale under the Influence of CO_(2)

作　　者：田港华 王海柱[1] 孙廉贺 王斌[1] TIAN Ganghua;WANG Haizhu;SUN Lianhe;WANG Bin(State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]油气资源与工程全国重点实验室,中国石油大学(北京),北京102249

出　　处：《华南师范大学学报(自然科学版)》2025年第1期92-99,共8页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(52341401);陕西省创新能力支撑计划项目(2023-CX-TD-31)。

摘　　要：为明确CO_(2)作用下页岩力学性质演化规律,对准噶尔盆地风城组页岩开展了CO_(2)-水-岩反应和单轴压缩实验,获取了应力-应变曲线、力学强度和破坏特征。结果表明:应力-应变曲线表现为压缩密实、弹性变形、塑性屈服和峰后破坏4个阶段,随CO_(2)浸泡时间增加,压缩密实段延长,峰后特征由“陡峭式”骤降转变为“台阶式”跌落。在CO_(2)的溶蚀和吸附作用下抗压强度和弹性模量逐渐下降,且劣化度随作用时间增加而增大。CO_(2)作用下,页岩破坏模式由脆性破坏向塑性破坏转变,裂缝复杂程度增加。页岩抗压强度降低有助于降低起裂压力、形成复杂缝网,提升压裂改造效果,但增加了CO_(2)泄露风险,影响CO_(2)封存的长期稳定性。研究成果可为页岩储层前置CO_(2)压裂工艺设计和碳封存安全性评价提供理论借鉴。To clarify the evolution law of shale mechanical properties under the action of CO_(2),CO_(2)-water-rock reaction experiments and uniaxial compression experiments were carried out on the shale of Fengcheng Formation in the Junggar Basin,and stress-strain curves,mechanical strengths,and failure characteristics were obtained.The results demonstrated that the stress-strain curve has four stages:compaction,elastic deformation,plastic yielding,and post-peak damage.As CO_(2)soaking time increased,the compaction stage was prolonged,accompanied by a change in the post-peak characteristic from a“steep”drop to a“step-like”fall.The compressive strength and elastic modulus decreased by CO_(2)dissolution and adsorption.The shift in failure mode from brittle to plastic resulted in increased fracture complexity.The reduction in shale compressive strength helped reduce fracture initiation pressure,form complex fractures,and increase fracturing efficiency.However,it also increased the risk of CO_(2)leakage and affected the long-term stability of CO_(2)sequestration.Research results can provide theoretical reference for the design of the pre-CO_(2)fracturing and the evaluation of the safety of carbon sequestration in shale reservoirs.

关 键 词：页岩 超临界CO_(2) 单轴压缩 应力-应变 破坏模式 

分 类 号：TU452[建筑科学—岩土工程]