摘要
为明确玛湖致密砾岩储层水力压裂后缝网发育特征,借鉴北美水力压裂试验场的成功经验,在玛131井区三叠系百口泉组二段(T1b2)和三段(T1b3)建立水力压裂现场实验室,共实施12口水平井和1口大斜度取心井,根据取心井MaJ02岩心裂缝CT扫描、成像测井以及岩心直接观测结果,结合示踪剂监测资料,研究水力压裂缝产状、连通情况、扩展规律和主控因素。研究表明:①水力压裂形成张性和剪切两种性质的裂缝,张性缝近似平行于最大水平主应力方向,自井筒射孔簇最远可延伸50 m;剪切缝分布于张性缝之间,大部分受缝间诱导应力场影响呈走滑剪切模式,部分呈共轭成对出现,整体上压裂缝呈先张后剪、张剪相间、剪切为主的特征。②示踪剂监测结果表明,生产早期井间普遍存在连通,随着生产的进行,缝内静压力逐渐降低,井间连通性下降。③岩性和压裂参数影响水力裂缝密度,泥岩夹层水力裂缝密度低于砾岩,并限制裂缝的扩展;更大的改造规模、更小的簇间距可提高裂缝密度,是提高单井产量的重要方向。
In order to identify the development characteristics of fracture network in tight conglomerate reservoir of Mahu after hydraulic fracturing,a hydraulic fracturing test site was set up in the second and third members of Triassic Baikouquan Formation(T1b2 and T1b3)in Ma-131 well area,which learned from the successful experience of hydraulic fracturing test sites in North America(HFTS-1).Twelve horizontal wells and a high-angle cored well MaJ02 were drilled.The occurrence,connection,propagation law and major controlling factors of hydraulic fractures were analyzed by comparing results of CT scans,imaging logs,direct observation of cores from Well MaJ02,and combined with tracer monitoring data.Results indicate that:(1)Two types of fractures have developed by hydraulic fracturing,i.e.tensile fractures and shear fractures.Tensile fractures are approximately parallel to the direction of the maximum horizontal principal stress,and propagate less than 50 m from the perforation cluster.Shear fractures are distributed among tensile fractures and mainly in the strike-slip mode due to the induced stress field among tensile fractures,and some of them are in conjugated pairs.Overall,tensile fractures alternate with shear fractures,with shear fractures dominated and activated after tensile ones.(2)Tracer monitoring results indicate that communication between wells was prevalent in the early stage of production,and the static pressure in the fracture gradually decreased and the connectivity between wells reduced as production progressed.(3)Density of hydraulic fractures is mainly affected by the lithology and fracturing parameters,which is smaller in the mudstone than the conglomerate.Larger fracturing scale and smaller cluster spacing lead to a higher fracture density,which are important directions to improve the well productivity.
作者
覃建华
鲜成钢
张景
梁天博
王文中
李思远
张津宁
张阳
周福建
QIN Jianhua;XIAN Chenggang;ZHANG Jing;LIANG Tianbo;WANG Wenzhong;LI Siyuan;ZHANG Jinning;ZHANG Yang;ZHOU Fujian(Research Institute of Exploration and Development,PetroChina Xinjiang Oilfield Company,Karamay 834000,China;Unconventional Petroleum Research Institute,China University of Petroleum(Beijing),Beijing 102249,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610599;State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;China National Petroleum Corporation Changqing Oilfield Sulige Gas Field Development Branch,Xi’an 710018,China;China University of Petroleum(Beijing)at Karamay,Karamay 834000,China)
出处
《石油勘探与开发》
北大核心
2025年第1期217-228,共12页
Petroleum Exploration and Development
基金
国家自然科学基金面上项目(52274051)
中国石油-中国石油大学(北京)战略合作项目(ZLZX2020-01)。
关键词
致密砾岩
致密油
水力压裂现场实验室
大斜度井取心
张性缝
剪切缝
缝网特征
tight conglomerate
tight oil
hydraulic fracturing test site
high-angle coring
tensile fractures
shear fractures
fracture network features
