不同构造单元页岩孔隙结构差异及其油气地质意义——以四川盆地泸州地区深层页岩为例  

Pore structure difference of shale in different structural units and its petroleum geological implications:A case study on deep shale in the Luzhou area,southern Sichuan Basin

作　　者：唐洪明[1] 刘贤 陈洋 于魏铭 赵宁 石学文 王猛 廖纪佳[1] TANG Hongming;LIU Xian;CHEN Yang;YU Weimin;ZHAO Ning;SHI Xuewen;WANG Meng;LIAO Jijia(School of Geoscience and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China;School of EnergyResources,China University of Geosciences-Beijing,Beijing 100083,China;Shale Gas Research Institute,PetroChina SouthwestOil&Gasfield Company,Chengdu,Sichuan 610051,China;CNOOC China Limited Hainan Company,Haikou,Hainan 570100,China;Southwest Petroleum University Science Park Development Co.,Ltd.,Chengdu,Sichuan 610500,China;School of PetroleumEngineering,Chongqing University of Science and Technology,Chongqing 401331,China)

机构地区：[1]西南石油大学地球科学与技术学院 [2]中国地质大学(北京)能源学院 [3]中国石油西南油气田公司页岩气研究院 [4]中海石油(中国)有限公司海南分公司 [5]成都西南石油大学科技园发展有限公司 [6]重庆科技大学石油与天然气工程学院

出　　处：《天然气工业》2024年第5期16-28,共13页Natural Gas Industry

基　　金：中国石油—西南石油大学创新联合体项目“川南深层与昭通中浅层海相页岩气规模效益开发关键技术研究”(编号:2020CX020102);重庆市自然科学基金项目“超临界CO_(2)提高页岩气藏采收率及封存机理研究”(编号:CSTB2023NSCQ-LZX0078)。

摘　　要：不同构造单元页岩储层品质、含气性差异明显,构造改造作用对页岩气勘探开发具有控制作用,但关于深层页岩气的构造控制作用机理研究较少,相关认识尚不明确,制约了深层页岩气的勘探开发。为此,通过“岩心—薄片—扫描电镜”多尺度观察、全岩矿物X射线衍射分析、核磁共振等技术手段,对比分析了四川盆地南部泸州地区不同构造单元上奥陶统五峰组—下志留统龙马溪组深层页岩孔隙结构和储层特征的差异,探讨了不同构造单元页岩孔隙结构差异与储层品质的耦合关系,明确了页岩气产量差异的内在地质原因,落实了构造改造作用下的页岩气勘探开发有利区。研究结果表明:①向斜区页岩主要以有机质孔隙、非构造裂缝为主,孔径大;背斜区页岩孔隙结构被强烈改造,以矿物粒间孔、构造裂缝为主,矿物粒间孔狭长且定向排列,孔径小。②向斜区构造相对稳定,有机质孔隙、矿物粒间孔以及成岩裂缝保存较好,宏孔占比高,储集性能好,含气量和产量高;背斜区页岩储层发育大量构造裂缝与断层,孔隙和成岩裂缝被压实,孔径减小,储集性能变差,含气量和产量低。③距盆缘剥蚀区越远,构造越稳定的单元,保存条件越好,该类构造单元页岩储层越发育,含气量和产量越高,页岩气勘探开发潜力越大。结论认为,构造运动对于压力系统的影响是形成不同构造单元深层页岩孔隙结构特征差异的重要因素,并控制了页岩储层的含气性与产量;向斜区深层保存条件好,远离剥蚀区,为勘探开发的最有利区,该认识可为深层页岩气勘探开发提供技术支撑。Different structural units present obvious differences in shale reservoir quality and gas content.Tectonic reworking action has a controlling effect on shale exploration and development,but the structure controlling mechanism of deep shale gas is less researched and not understood clearly,which restricts the exploration and development of deep shale gas.In this paper,the differences in pore structures and reservoir characteristics of deep shale from Upper Ordovician Wufeng Formation to Lower Silurian Longmaxi Formation in different structural units in the Luzhou area of southern Sichuan Basin are comparatively analyzed by means of core-thin section-SEM multi-scale observation,whole-rock mineral X-ray diffraction analysis and NMR analysis.In addition,the coupling relationships between shale pore structural difference and reservoir quality in different structural units are discussed,the internal geological reasons for the difference in shale gas production are identified,and the favorable areas for shale gas exploration and development under tectonic reworking action are defined.And the following research results are obtained.First,the shale in the syncline area is dominated by organic pores and abnormal-pressure fractures with larger pore sizes,while the shale pore structure in the anticlinal area suffers strong reworking and is dominated by mineral intergranular pores and tectonic fractures.The mineral intergranular pores are arranged directionally in a narrow and long pattern,and small in size.Second,in the syncline area,the structures are relatively stable,organic pores,mineral intergranular pores and diagenetic fractures are well preserved,and the proportion of macropores is higher,so the reservoir performance is good,and the gas content and production rate are high.In the anticline area,a large number of tectonic fractures and faults are developed in shale reservoirs,pores and diagenetic fractures are compacted,and pore size decreases,so the reservoir performance deteriorates,and the gas content and productio

关 键 词：四川盆地 泸州地区 构造单元 上奥陶统五峰组—下志留统龙马溪组 深层页岩 孔隙结构 含气性 构造作用 

分 类 号：P618.13[天文地球—矿床学]