川东北营山平昌地区凉高山组页岩天然裂缝发育特征及其形成演化模式研究  

Nature fractures in shales of the Lianggaoshan Formation in northern Sichuan Basin:Fracture development characteristics and fracture formation and evolution model

作　　者：何建华 曹红秀 邓虎成[1,3] 印长海[4] 朱彦平[4] 李厂 李勇[4] 尹帅 HE Jianhua;CAO Hongxiu;DENG Hucheng;YIN Changhai;ZHU Yanping;LI Chang;LI Yong;YIN Shuai(College of Energy,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development,Beijing 102206,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Research Institute of Exploration and Development,Daqing Oilfield Co.,Ltd,Daqing 163000,China;School of Earth Sciences and Engineering,Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]成都理工大学能源学院,四川成都610059 [2]页岩油气富集机理与高效开发全国重点实验室,北京102206 [3]油气藏地质及开发工程全国重点实验室(成都理工大学),四川成都610059 [4]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163000 [5]西安石油大学地球科学与工程学院,陕西西安710065

出　　处：《地学前缘》2024年第5期17-34,共18页Earth Science Frontiers

基　　金：国家自然科学基金面上项目(42072182);青年基金项目(42402148);四川省科技厅重点苗子项目(2022JDRC0103);四川省杰出青年科技人才项目“页岩气储层天然裂缝评价(2020JDJQ0058)”;页岩油气富集机理与高效开发全国重点实验室开放基金项目(P24181)。

摘　　要：川东北营山平昌地区侏罗系凉高山组页岩油气显示活跃且多口井获得工业油气流,其油气资源勘探潜力巨大,而侏罗系页岩油气的富集程度及开发效果受控天然裂缝特征明显。本文综合利用野外、成像、岩心、薄片和CT扫描等多尺度裂缝表征手段,并结合脉体包裹体、碳氧同位素、岩石声发射和脉体U-Pb定年实验测试,重点揭示了研究区不同尺度天然裂缝的发育特征,明确了不同成因天然裂缝的形成期次并构建了其演化力学模式。结果表明:凉高山组页岩主要发育剪切缝、层面滑移缝、层理缝和流体超压缝等力学成因裂缝;构造变形区以发育NW和NE向高角度剖面剪切缝和网状张剪复合缝为主,裂缝密度高,纵向穿层规模大;平稳稳定区主要发育层理缝和流体超压缝及少量近EW和NNE向平面剪切缝,密度低,多充填。侏罗系主要经历了4个天然裂缝形成期:燕山早—中期(170~140 Ma)侏罗系快速埋藏形成以近SN和NE向垂直或水平的水力超压裂缝为主,纤维状方解石全充填;燕山晚期(100~80 Ma)发育NNE与近EW共轭平面剪切裂缝、NE向扩张缝和生烃超压缝;喜马拉雅早—中期(67~32 Ma)持续发育平面剪切缝、NW向剖面剪切缝和张性缝,以及层理缝;喜马拉雅晚期(15~6 Ma)表现为先存裂缝的活化和新生成少量近NNE向张性缝。受喜马拉雅晚期应力调整,早期形成近EW和NW向剪切缝开启有效,新生成的NNE向张性缝未充填较有效。该研究对于侏罗系多期构造复合下有效裂缝的定量预测和页岩油气富集有利区优选提供了重要支撑。The Jurassic Lianggaoshan Formation in Yingshan-Pingchang region,northeastern Sichuan has great exploration potential for shale oil and gas resources.To better understand the control of natural fractures on oil and gas enrichment and reservoir production,this paper utilizes multi-scale fracture characterization methods such as field observation,imaging,core logging,thin section,and CT scanning,combined with vein inclusion analysis,carbon-oxygen isotope analysis,acoustic emission testing,and U-Pb dating of veins.The characteristics of the multiscale fracture system in the study area are revealed;the formation history of natural fractures of different origins are clarified;and the fracture evolution model is constructed.The Jurassic shale reservoir mainly develops mechanical types of fractures,such as shear fractures,bedding slip fractures,bedding fractures,and fluid overpressure fractures.The tectonic deformation zone is dominated by NW-/NE-striking,high-angle parallel shear fractures and reticulate tension-shear hybride fractures,with high fracture density and large-scale vertical interlayers.The stable zone is characterized by bedding fractures,fluid overpressure fractures,and a small number of near-EW-/NNE-striking planar shear fractures,with low fracture density and high fracture filling.The Jurassic mainly experienced four episodes of fracture development:the early-middle Yanshanian(170140 Ma),with the formation of near SN/NE-striking hydraulic overpressure fractures fully filled with fibrous calcite;the late Yanshanian(10080 Ma),with the development of NNE-/near-EW-striking conjugate planar shear fractures,NE-striking expansion fractures,and hydrocarbon generation overpressure fractures;the early-middle Himalayan(6732 Ma),with the continued development of planar shear fractures,NW-treding parallel shear fractures,longitudinal tension fractures,and bedding fractures;and the late Himalayan(156 Ma)with the activation of pre-existing fractures and formation of small number of NNE-striking tensile fractures.This

关 键 词：页岩储层 天然裂缝 形成演化 有效性 凉高山组 营山平昌地区 

分 类 号：P618.13[天文地球—矿床学]