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 thru...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 the Longmenshan Mountain and the Sichuan Basin,but also the boundary of the oil/gas accumulation system in northwestern Sichuan Basin.展开更多
In this paper,the technology of wave process method for sedimentation is first adopted in the research of the foreland thrust fault of Micang Mountain with respect of oil and reservoir’s formation and tectonic and se...In this paper,the technology of wave process method for sedimentation is first adopted in the research of the foreland thrust fault of Micang Mountain with respect of oil and reservoir’s formation and tectonic and sedimentary evolution. From the fluctuation characteristics,we could make conclusions in the foreland thrust belt of Micang Mountain that,there existed 2 first-order sedimentary cycles (220 Ma),corresponding to Caledonian-Hercynian and Indo-Chinese-Yanshan-Himalayan tectonic cycles respec-tively; there existed 4 second-order sedimentary cycles (10 Ma),corresponding to two sedimentation peak period and two denudation peak periods in research zone; there existed 12 third-order sedimen-tary cycles (35 Ma) and 21 fourth-sedimentary cycles (20 Ma). These 33 cycles in the research zone corresponded to the sedimentation-denudation process in different periods,furthermore,their fluctua-tion characteristics bore the genetic relationship with the development law of source,reservoir and cap rocks: the source rock had the tendency to develop at the turning part between wave crest and wave trough,or at the superposition of wave turning part in different periods,presenting like "X"; most res-ervoir rocks developed at the place of wave peak; the development of cap rock was located in the wave trough on the right of sedimentation-denudation datum line. As a result,through the application of wave process method for sedimentation,we could rediscover the understanding of the tectonic and sedimentary evolution from another prospective,meanwhile,it enables to make prediction about the development rule of source,reservoir and cap rocks,which means a significant importance to the re-search of oil and reservoir’s forming condition.展开更多
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)。
文摘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 the Longmenshan Mountain and the Sichuan Basin,but also the boundary of the oil/gas accumulation system in northwestern Sichuan Basin.
基金Supported by National Basic Research Program of China (Grant No.2005CB422107)
文摘In this paper,the technology of wave process method for sedimentation is first adopted in the research of the foreland thrust fault of Micang Mountain with respect of oil and reservoir’s formation and tectonic and sedimentary evolution. From the fluctuation characteristics,we could make conclusions in the foreland thrust belt of Micang Mountain that,there existed 2 first-order sedimentary cycles (220 Ma),corresponding to Caledonian-Hercynian and Indo-Chinese-Yanshan-Himalayan tectonic cycles respec-tively; there existed 4 second-order sedimentary cycles (10 Ma),corresponding to two sedimentation peak period and two denudation peak periods in research zone; there existed 12 third-order sedimen-tary cycles (35 Ma) and 21 fourth-sedimentary cycles (20 Ma). These 33 cycles in the research zone corresponded to the sedimentation-denudation process in different periods,furthermore,their fluctua-tion characteristics bore the genetic relationship with the development law of source,reservoir and cap rocks: the source rock had the tendency to develop at the turning part between wave crest and wave trough,or at the superposition of wave turning part in different periods,presenting like "X"; most res-ervoir rocks developed at the place of wave peak; the development of cap rock was located in the wave trough on the right of sedimentation-denudation datum line. As a result,through the application of wave process method for sedimentation,we could rediscover the understanding of the tectonic and sedimentary evolution from another prospective,meanwhile,it enables to make prediction about the development rule of source,reservoir and cap rocks,which means a significant importance to the re-search of oil and reservoir’s forming condition.
