湘鄂西—渝东褶皱带多重滑脱构造变形特征与构造模型  

Deformation characteristics and structural model of multi-layer detachment structures in the western Hu'nan and Hubei to eastern Chongqing fold belt

作　　者：李英强 何登发[2] 李双建[1] Li Yingqiang;He Dengfa;Li Shuangjian(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083;China University of Geosciences Beijing,Beijing 100083)

机构地区：[1]中国石化石油勘探开发研究院,北京100083 [2]中国地质大学(北京)能源学院,北京100083

出　　处：《地质科学》2020年第3期894-908,共15页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家科技重大专项(编号:2017ZX05036083);国家自然科学基金项目(编号:U19B6003,91755211,41430316)资助。

摘　　要：湘鄂西—渝东褶皱带为多层系、多类型天然气大型聚集区,揭示其结构与成因将为拓展该区勘探新领域提供重要依据,为其它陆内强构造变形区的油气评价提供重要参考。本文利用两条拼接的跨研究区的地震反射剖面,以断层相关褶皱几何学、运动学分析方法为指导,对湘鄂西—渝东褶皱带进行精细构造解析。研究结果表明,湘鄂西—渝东褶皱带构造变形主要与4套区域滑脱层有关,具有多层次拆离、多级别滑脱、多方向冲断及多样式组合的特征。纵向上由深及浅依次以低幅度构造、双重构造和冲褶构造为主要特征,空间上自南东向北西总体为由基底滑脱向盖层滑脱、由单层滑脱向多层滑脱的陆内递进式变形。湘鄂西—渝东地区存在多套“源—储—盖”组合,基于多重滑脱构造变形系统及“相对稳定”保存单元概念,认为未来常规天然气勘探可重点关注寒武系盐下领域,非常规页岩气需继续加强对寒武系、志留系、二叠系构造弱变形区的评价。The western Hu􀆳nan and Hubei to eastern Chongqing area is a large multi-layer and multi type natural gas accumulation area.Revealing its structure and origin will provide an important basis for expanding the new exploration field in this area and an essential reference for oil and gas evaluation in other strong intracontinental structural deformation areas.Based on the two spliced seismic reflection sections across the study area and guided by the geometry and kinematic analysis methods of fault related folding theory,this paper analyzes the fine structure of the western Hu􀆳nan and Hubei to eastern Chongqing fold belt.The results show that the structural deformation in the study area is mainly related to four sets of regional detachment layers,which are characterized by multi-layer detachment,multi-level detachment,multi-directional thrust and multi-style combination.Vertically,from deep to shallow,it is mainly characterized by low amplitude structure,duplex structure and thrust fold structure;spatially,from southeast to northwest,it is generally characterized by progressive deformation from basement detachment to caprock detachment,from single-layer detachment to multi-layer detachment.A number of“source-reservoir-cap”assemblages have been found in the western Hu􀆳nan and Hubei to eastern Chongqing.Based on the concept of multi-layer detachment structural deformation system and“relatively stable”preservation unit,the author thinks that conventional natural gas exploration in the future can focus on the Cambrian sub-salt fields,while unconventional shale gas needs to continue to strengthen the evaluation of structural weak deformation zone of Cambrian,Silurian and Permian.

关 键 词：滑脱层 多重滑脱 构造特征 陆内变形 湘鄂西—渝东 

分 类 号：P542[天文地球—构造地质学]