深层页岩射孔条件下原位应力场对水力裂缝起裂和复杂性的影响  

The impact of geomechanics and perforations on hydraulic fracture initiation and complexity in deep shale reservoirs

作　　者：刘英君 鲜成钢 梁兴 张介辉 李后俊 刘云翼 LIU Yingjun;XIAN Chenggang;LIANG Xing;ZHANG Jiehui;LI Houjun;LIU Yunyi(State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum-Beijing,Beijing 102249,China;PetroChina Zhejiang Oilfield Company,Hangzhou 311100,China)

机构地区：[1]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [2]中国石油浙江油田公司,杭州311100

出　　处：《石油科学通报》2025年第1期120-132,共13页Petroleum Science Bulletin

基　　金：国家重点研发计划项目(2020YFA0710604)资助。

摘　　要：鉴于非常规各向异性储层水力压裂射孔簇非均匀起裂的科学难题,本文考虑弱面各向异性,射孔孔眼与井筒的应力集中效应的叠加,建立了任意定向井眼与射孔孔眼的应力模型与水力裂缝起裂形态预测的解析模型,研究了垂直缝、水平缝的起裂条件。对罗布区块产量差异最大的两口井进行力学分析,研究结果表明:射孔孔眼周围的应力分布对裂缝起裂压力有显著影响,从而影响了井筒附近裂缝的几何形状。在沿最小水平主应力方向布井且主要处于走滑偏正断层应力状态的Y1井中,未产生气液的主要力学原因是井眼与射孔通道两次应力集中导致近井原位应力场的水平主应力反转,应力状态变为逆断层,近井主要为水平缝,气液运移通道受阻。处于走滑偏正断层应力状态的Y2井中,两次应力集后应力状态变为走滑偏逆断层,垂直缝起裂范围占比75%以上,近井裂缝通道连通性较好,有助于储层气液的运移。本研究可为水力压裂的射孔优化设计提供参考,为现场实际应用提供了最小的起裂压力与最佳井筒—油藏连接通道的射孔方向。In view of the scientific problem of non-uniform initiation of hydraulic fracturing perforation clusters in unconventional anisotropic reservoirs,this paper considers the anisotropy of weak plane and the superposition of stress concentration effect of perforation hole and wellbore,and establishes the stress model of arbitrary directional hole and perforation hole and the analytical model of hydraulic fracture initiation morphology prediction.The initiation conditions of vertical and horizontal fractures are studied.the mechanical analysis of two wells with the largest difference in production in Luobu block is carried out.The results show that the stress distribution around the perforation hole has a significant influence on the fracture initiation pressure,which affects the geometry of the fracture near the wellbore.In well Y1,which is arranged along the direction of the minimum horizontal principal stress and is mainly in the stress state of the strike-slip partial normal fault,the main mechanical reason for the absence of gas-liquid is that the two stress concentrations of the borehole and the perforation channel lead to the reversal of the horizontal principal stress of the in-situ stress field near the well,and the stress state becomes reverse fault.The near well is mainly horizontal fracture,and the gas-liquid migration channel is blocked.In the Y2 well,which is in the stress state of the strike-slip normal fault,the stress state becomes a strike-slip reverse fault after two stress sets,and the vertical fracture initiation range accounts for more than 75%.The connectivity of the near-well fracture channel is good,which is helpful for the migration of gas and liquid in the reservoir.This study offers insights for the optimal design of perforation holes in hydraulic fracturing,providing information on the minimum fracture initiation pressure and the optimal perforation direction for the wellbore-reservoir connecting channel in practical field applications.

关 键 词：页岩气 应力集中 水平主应力反转 水平缝 射孔优化 

分 类 号：TE377[石油与天然气工程—油气田开发工程] P618.13[天文地球—矿床学]