机构地区:[1]华北水利水电大学地球科学与工程学院,河南郑州450046 [2]中国水利水电建设工程咨询西北有限公司,陕西西安710100 [3]黄河勘测规划设计研究院有限公司,河南郑州450003 [4]郑州大学利与交通学院,河南郑州450001 [5]中国水利水电第十一工程局有限公司,河南郑州450001
出 处:《水利水电技术(中英文)》2025年第3期236-250,共15页Water Resources and Hydropower Engineering
基 金:国家自然科学基金项目(51709113);河南省重点研发专项(241111322900)。
摘 要:【目的】层理面力学参数对页岩水力压裂裂缝的起裂及扩展行为具有显著影响,而目前针对层理面倾角及强度等对裂缝影响规律和机制的研究并不充分。【方法】利用ABAQUS有限元软件,采用全局零厚度Cohesive单元开展二维数值模拟,基于Python编程提取水力裂缝的力学参数,分析层理面倾角、层理面强度和地应力差对压裂裂缝扩展的影响。【结果】研究结果表明:(1)层理面倾角对于水力压裂裂缝的扩展方式影响较大,在0°~90°范围内,当层理面倾角为45°时裂缝长度最长,裂缝数量最多。(2)层理面强度越弱,水力压裂裂缝的扩展路径受层理面影响越显著,更容易沿着层理面产生低缝宽的剪切裂缝。(3)当地应力差从2 MPa增加至8 MPa时,水力压裂裂缝的偏转效应越显著,即裂缝更容易向着大主应力方向扩展。(4)与层理面强度和地应力差相比,层理面倾角对水力压裂裂缝的影响更为显著。(5)根据水力压裂裂缝与层理面之间的相互作用方式,将裂缝形态分为贯穿、转向、分叉和捕获四种形式,随着层理面倾角的增加,水力压裂裂缝由贯穿向分叉或转向转变。【结论】层理面倾角、层理面强度和地应力差三种影响因素当中,层理面倾角对压裂裂缝的影响最为显著。[Objective]The mechanical parameters of bedding planes have a significant influence on the initiation and propagation of hydraulic fractures in shale.However,current research on the effects and mechanisms of bedding plane inclination angle and strength on fractures remains limited.[Methods]ABAQUS finite element software was utilized in this study to conduct two-dimensional numerical simulations by adopting the global zero-thickness cohesive element.Python programming was employed to extract the mechanical parameters of hydraulic fractures,and the effects of bedding plane inclination angle,bedding plane strength,and in-situ stress difference on fracture propagation were analyzed.[Results]The result indicated that:(1)the bedding plane inclination angle had a significant impact on the propagation patterns of hydraulic fractures.Within the range of 0°to 90°,when the bedding plane inclination angle was 45°,the fracture length was the longest,and the number of fractures was the largest.(2)Weaker bedding plane strength result ed in more significant effects of the bedding plane on the propagation path of hydraulic fractures,making it easier for narrow-width shear fractures to develop along the bedding plane.(3)When the difference in stress increased from 2 MPa to 8 MPa,the deflection effect of hydraulic fracturing fractures became more prominent,meaning that the fractures were more likely to propagate in the direction of the major principal stress.(4)Compared with bedding plane strength and in-situ stress difference,the bedding plane inclination angle had a more significant impact on hydraulic fractures.(5)Based on the interaction between hydraulic fractures and bedding plane,fracture patterns were divided into four types:penetration,deflection,bifurcation,and capture.As the bedding plane inclination angle increased,hydraulic fractures transitioned from penetration to bifurcation or deflection.[Conclusion]Among the three influencing factors,namely bedding plane inclination angle,bedding plane strength,and in-situ stre
分 类 号:TE357[石油与天然气工程—油气田开发工程]
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