川南长垣坝横跨叠加构造变形与古流体运移特征对页岩气保存条件分析OA
Analysis of shale gas preservation conditions based on tectonic deformation across superposition and paleo-fluid migration characteristics of Changyuanba in southern Sichuan
川南低缓褶皱带的长垣坝构造带,历经多期构造运动,形成典型的横跨叠加构造,其东部的遵义市赤水区块五峰组-龙马溪组页岩气勘探效果不佳,反映了该区复杂的构造对页岩气保存条件具有重要的影响.针对此问题本文进行了精细地震构造解释,并详细分析了TY1井不同层位的裂缝发育特征,还通过碳、氧、锶同位素地球化学分析,明确了复杂构造对页岩气保存的控制作用.研究结果表明长垣坝构造带主要发育南北向和东西向 2组受滑脱层控制的褶皱构造.受强构造挤压应力影响发育闭合背斜和高陡逆断层,两者共同控制了五峰组-龙马溪组底部顺层或低角度断裂缝和茅口组中-高角度裂缝的发育.同位素测试揭示了 3种流体来源,其中五峰组-龙马溪组样品的87Sr/86Sr富集,且脉体的δ13C和δ18O较围岩偏负,指示该地层以深部热液流体为主,存在跨层运移,封闭性较差.二叠系茅口组中热液流体来源丰富,地层下部以同层碳酸盐岩流体为主,上部以深部热液流体为主,存在跨层流体活动,封闭性被破坏.三叠系飞仙关组以同层异位碳酸盐岩流体活动为主,有深部热液的参与,封闭性一般.综上所述,长垣坝构造带构造变形强,发育逆冲断层,裂缝和断层结合构成的断裂缝立体网格为页岩气长期的逸散通道,导致东西向断层带上盘保存条件相对较差.
The Changyuanba structural belt,located in the low fold belt in southern Sichuan,has undergone multiple tectonic movements and formed a typical superposition structure.The shale gas exploration conditions of the Wufeng-Longmaxi Formation in the Chishui block to the east of the belt are not good,which reflect that the complex structure in this area has an important influence on the preservation conditions of shale gas.To solve this problem,we carried out fine seismic structural interpretation and analyzed the fracture development characteristics of different formations in the Well TY1.Through the geochemical analysis of carbon,oxygen,and strontium isotopes,the controlling effect of complex structures on shale gas preservation has been clarified.The research results show that the Changyuanba structural belt mainly developed two groups of fold structures controlled by detachment layers in the north-south and east-west directions.Under the influence of strong tectonic compressive stress,closed anticlinal and a high steep reverse fault developed,which jointly controlled the development of bedding,and which produced a low-angle fault fracture at the bottom of the Wufeng-Longmaxi Formation and a middle-to high-angle fracture in the Maokou Formation.Isotope tests revealed three types of fluid sources,with 87Sr/86Sr enrichment in the Wufeng-Longmaxi Formation samples,while δ13C and δ18O in the vein body were found to be depleted relative to the surrounding rock,indicating that the formation was dominated by deep hydrothermal fluid,with cross-layer migration and poor sealing.The Permian Maokou Formation is rich in fluid sources:the lower part of the formation is dominated by carbonate fluid and the upper part is dominated by deep hydrothermal fluid;there is also cross-layer fluid activity,with negligible sealing between layers.The Triassic Feixianguan Formation was dominated by the fluid activity of isotopic carbonate rocks,including the participation of deep hydrothermal fluid,and its sealing property is poor.In summary,the Changyuangba tectonic belt contains strong tectonic deformation and developed thrust faults,and the three-dimensional network of fault fractures provides long-term escape channels for shale gas,resulting in relatively poor preservation conditions
谢荣洁;李智武;李金玺;刘树根;叶玥豪;童馗;张毫生;魏力民;孟宪武
油气藏地质及开发工程全国重点实验室(成都理工大学),成都 610059油气藏地质及开发工程全国重点实验室(成都理工大学),成都 610059成都理工大学 地球物理学院,成都 610059成都理工大学,成都 610059油气藏地质及开发工程全国重点实验室(成都理工大学),成都 610059油气藏地质及开发工程全国重点实验室(成都理工大学),成都 610059油气藏地质及开发工程全国重点实验室(成都理工大学),成都 610059中国石油化工西南油气分公司 勘探开发研究院,成都 610041中国石油化工西南油气分公司 勘探开发研究院,成都 610041
天文与地球科学
五峰组-龙马溪组长垣坝构造带构造保存古流体页岩气
Wufeng-Longmaxi FormationChangyuanba structural beltstructural preservationpaleo-fluidshale gas
《成都理工大学学报（自然科学版）》 2026 (2)
282-300,19
新型油气勘探开发国家科技重大专项课题(2025ZD1400403)国家自然科学基金项目(U2344209).
评论