Structural characteristics and implications on oil/gas accumulation in north segment of the Longmenshan piedmont,northwestern Sichuan Basin,SW China  

作　　者：LIANG Han WEN Long RAN Qi HAN Song LIU Ran CHEN Kang DI Guidong CHEN Xiao PEI Yangwen 

机构地区：[1]Research Institute of Exploration and Development,Southwest Oil&Gas Field Company,Chengdu 610041,China [2]School of Geosciences,China University of Petroleum,Qingdao 266580,China [3]Key Laboratory of Deep Oil and Gas(China University of Petroleum(East China)),Qingdao 266580,China

出　　处：《Petroleum Exploration and Development》2022年第3期546-559,共14页石油勘探与开发（英文版）

基　　金：Supported by the National Natural Science Foundation of China(41872143);National Science and Technology Major Project of China(2016ZX05007-004);PetroChina Science and Technology Major Project(2016E-0604)。

摘　　要：By integrating surface geology,seismic data,resistivity sections,and drilling data,the structural deformation characteristics of the frontier fault of thrust nappes were delineated in detail.The frontier fault of thrust nappes in northwest Scihuan Basin is a buried thrust fault with partial exposure in the Xiangshuichang-Jiangyou area,forming fault propagation folds in the hanging-wall and without presenting large-scale basin-ward displacement along the gypsum-salt layer of the Triassic Jialingjiang Formation to the Triassic Leikoupo Formation.The southwestern portion of the frontier fault of thrust nappes(southwest of Houba)forms fault bend folds with multiple ramps and flats,giving rise to the Zhongba anticline due to hanging-wall slip along the upper flat of the Jialingjiang Formation.In contrast,the northeastern portion of the frontier fault of thrust nappes(northeast of Houba)presents upward steepening geometry,leading to surface exposure of Cambrian in its hanging-wall.With the frontier fault of thrust nappes as the boundary between the Longmenshan Mountain and the Sichuan Basin,the imbricated structural belt in the hanging-wall thrusted strongly in the Indosinian orogeny and was reactivated in the Himalayan orogeny,while the piedmont buried structural belt in the footwall was formed in the Himalayan orogeny.In the footwall of the frontier fault of thrust nappes,the piedmont buried structural belt has good configuration of source rocks,reservoir rocks and cap rocks,presenting good potential to form large gas reservoirs.In comparison,the hanging-wall of the frontier fault of thrust nappes north of Chonghua has poor condition of oil/gas preservation due to the surface exposure of Triassic and deeper strata,while the fault blocks in the hanging-wall from Chonghua to Wudu,with Jurassic cover and thicker gypsum-salt layer of the Jialingjiang formation,has relative better oil/gas preservation conditions and thus potential of oil/gas accumulation.The frontier fault of thrust nappes is not only the boundary between

关 键 词：Sichuan Basin Longmenshan Mountain foreland basin foreland thrust belt fault-related folding gypsum-salt detachment thrust faulting hydrocarbon accumulation tectonic evolution 

分 类 号：P618.13[天文地球—矿床学]