干热岩亚临界裂纹扩展的实验研究  

Experimental Study on Subcritical Crack Growth in Hot Dry Rocks

作　　者：汪道兵 秦浩 马海燕 王丽群[3] 李敬法 孙东亮 宇波 WANG Daobing;QIN Hao;MA Haiyan;WANG Liqun;LI Jingfa;SUN Dongliang;YU Bo(School of Mechanical Engineering,Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil&Gas Development,Beijing Institute of Petrochemical Technology,Beijing 102617,P.R.China;Beijing Company,China Huanqiu Contracting&Engineering Co.Ltd,Beijing 100012,P.R.China;Institute of Mechanical Properties of Materials,Central South University,Changsha 410083,P.R.China)

机构地区：[1]北京石油化工学院机械工程学院,深水油气管线关键技术与装备北京市重点实验室,北京102617 [2]中国寰球工程有限公司北京分公司,北京100012 [3]中南大学材料力学性能研究所,湖北长沙410083

出　　处：《北京石油化工学院学报》2020年第4期7-12,28,共7页Journal of Beijing Institute of Petrochemical Technology

基　　金：国家自然科学基金项目(51804033、51936001和51904031);中国博士后科学基金项目(2018M641254);北京市博士后项目(2018-ZZ-045);北京市高水平创新团队建设计划项目(IDHT20170507);长城学者培养计划(CIT&TCD20180313);北京市重点联合基金项目(KZ201810017023)。

摘　　要：通过双扭试验伺服控制压机,在控制位移加载模式下,研究了干热岩在不同浸泡时间下的亚临界裂纹扩展特征。结果表明,干热岩样品亚临界裂纹扩展的门槛值一般约为断裂韧性的80%~90%左右,亚临界裂纹扩展速率与应力强度因子间服从幂律关系;在水化腐蚀环境下,干热岩的断裂韧性与时间呈现较好的负相关性,与干燥状态断裂韧性相比较,浸泡6、8 d时的断裂韧性分别降低了约13.8%和33.7%,同时,干热岩亚临界裂纹扩展参数会发生几个数量级的变化。水化腐蚀可促进干热岩细观人工裂缝形成,细观力学裂纹与主裂缝交汇贯通是其水力压裂形成复杂缝网的力学机制之一。The subcritical crack propagation characteristics of dry hot rock at different imbibition time are experimentally studied by the double-torque test servo-control device.The results show that the threshold value of subcritical crack propagation in dry hot rock samples is generally 80%~90%of fracture toughness.The subcritical crack growth rate and stress intensity factor obey the power law relationship.Under the action of stress corrosion environment,the fracture toughness of dry hot rock shows a good negative correlation with imbibition time.Compared with the fracture toughness of dry samples,the fracture toughness at 6 and 8 days of imbibition decreased by about 13.8%and 33.7%,respectively,while the subcritical crack propagation parameter A of dry hot rock occurred several orders of magnitude change.It indicates that water environment will promote the formation of meso-artificial cracks in dry hot rocks.The intersection between meso-mechanical cracks and the main cracks are one of the mechanical mechanisms of hydraulic fracturing to form complex fractures.

关 键 词：干热岩 双扭实验 水岩相互作用 损伤断裂性质 

分 类 号：TK521[动力工程及工程热物理—热能工程]