页岩—液体反应及其对地应力的影响

Shale-liquid Interaction and Its Effect on In-situ Stress

李皋 李泽 胡嵩 李明昊 李卓阳

LIGao LIZe HUSong LIMinghao LIZhuoyang

油气藏地质及开发工程全国重点实验室·西南石油大学, 四川 成都 610500 中国石油西南油气田工程技术研究院, 四川 成都 610017 中海油天津分公司, 天津 滨海新区 300450 中国石油西南油气田开发事业部, 四川 成都 610011

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Engineering Technology Research Institute, Southwest Oil and Gas Field Company, PetroChina, Chengdu, Sichuan 610017, China CNOOC China Limited, Tianjin Branch, Binhai New Area, Tianjin 300450, China Development Division, Southwest Oil and Gas Field Company, PetroChina, Chengdu, Sichuan 610011, China

页岩地层钻完井过程中，页岩—液体反应难以避免。为研究页岩—液体反应机理及其对地应力分布的影响，选取川南地区龙马溪组页岩，开展了页岩—液体反应室内实验，明确了其反应机理及结果。在此基础上利用数值模拟技术研究了页岩液体反应对地应力分布的影响。结果表明，页岩—液体反应将造成页岩损伤，衍生微裂缝，同时导致页岩的膨胀变形。页岩—液体反应将对应力分布状态产生影响，且影响程度与缝网复杂程度高度正相关。考虑页岩—液体反应后，压裂过程中地应力分布状态出现显著变化，并造成套管应力随页岩—液体作用时间增加，对套管变形产生影响。

During drilling and completion in shale formation, shale-liquid interaction between working fluid and shale is inevitable. In order to study the mechanism of shale-liquid interaction and its effect on in-situ stress distribution, laboratory experiments of shale-liquid interaction were carried out on Longmaxi Formation shale in southern Sichuan, and the mechanism and results of the shale-liquid interaction were clarified. On this basis, the influence of shale-liquid interaction on in-situ stress distribution was studied. The results show that the shale-liquid interaction can cause shale damage, and then the micro-fracture occurs, which leads to the shale swelling. The stress distribution can be affected during shale-liquid interaction, and the more complex the fracture network, the more obvious the influence of shale-liquid interaction on stress. Due to the shale-liquid interaction, the distribution of in-situ stress changes significantly during hydraulic fracturing, and the casing stress increases with the shale-liquid interaction time.

10.11885/j.issn.1674-5086.2022.06.29.01