深层页岩在差异化射孔条件下裂缝扩展规律研究  

Research on the Fracture Propagation Law at the Deep Shale under Differentiated Perforation

作　　者：陈健 CHEN Jian(Downhole Service Company of CNPC Chuanqing Drilling Engineering Co.,Ltd.,Chengdu,Sichuan 610051,China)

机构地区：[1]中国石油川庆钻探工程有限公司井下作业公司,四川省成都市610052

出　　处：《钻采工艺》2025年第2期102-108,共7页Drilling & Production Technology

基　　金：中国石油集团川庆钻探公司科研课题“基于人工应力干扰的缝网压裂机制研究及试验”(编号:CQ2022B-28-2-4)。

摘　　要：为了研究射孔密度和位置对深层页岩水力裂缝起裂和扩展方式的影响,采用室内真三轴水力压裂物理模拟试验机、声发射定位系统以及压裂液中添加示踪剂等方式,在真三轴条件下对大尺寸页岩露头开展水力压裂物理模拟试验。通过对岩样多段同时压裂明确页岩水力裂缝起裂条数的影响因素,探索岩样在不同射孔数量和差异化射孔位置下页岩起裂裂缝条数及裂缝延伸规律。试验结果表明:页岩的非均质、射孔分流和形成裂缝后的优势通道共同影响水力压裂的泵压和水力裂缝条数;页岩单段压裂过程中,为促使跟端趾端均匀起裂,推荐采用跟端少孔趾端多孔的差异化布孔方式;一定范围内,页岩的射孔数量与裂缝起裂数量非正相关,减少射孔数量能够促进裂缝起裂,提升孔眼开启率;利用射孔孔眼摩阻提高井底压力,能促进压裂段均匀起裂。该实验结果能为深层页岩压裂孔眼开启率提升与裂缝均衡扩展提供实验规律认识和参考依据。To study the influence of perforation density and location on the initiation and propagation of hydraulic fractures in deep shale,in-door true triaxial hydraulic fracturing physical simulation tester,acoustic emission location system and tracer added in the fracturing fluid have been used to carry out hydraulic fracturing tests on large-scale shale outcrops under true triaxial conditions.By simultaneously fracturing multiple sections of the rock samples,the factors affecting the number of hydraulic fractures in shale were clarified,and the number of fractures and the extension laws of fractures in shale under different perforation numbers and differentiated perforation locations were explored.The test results show that:The heterogeneity of shale,perforation diversion,and the preferential channels formed after the formation of fractures jointly affect the pump pressure and the number of hydraulic fractures;During the single interval fracturing of the shale,perforation distribution with more at the heel and less at the toe has been recommended to promote uniform initiation of fractures at the heel and the toe;Within a certain range,the number of perforations in shale is not positively correlated with the number of fractures initiated.Reducing the number of perforations is an important means to promote fracture initiation and can increase the perforation propagation rate.When multiple fractures are initiated,due to the stress shadow effect,the fractures compete for extension and show non-uniformity;BHP can be increased by enhancing the friction resistance of the perforations,which leads to the fractures initiated uniformly.The experimental results of the paper can provide the understanding of experimental law and reference basis for improving the perforation propagation rate and the uniform extension of the fractures in deep shale fracturing.

关 键 词：深层页岩 压裂 射孔孔数 起裂数量 裂缝扩展 

分 类 号：TE357[石油与天然气工程—油气田开发工程]