Geologic Structure And Hydrocarbon Accumulation Ofeastern Foreland In Amu Darya Right Bank

Eastern Foreland is located at the southeast of Amu Darya Right Bank,which lies between north of Amu Darya River and south of Turkmenistan-Uzbekistan Border.The study area close to SE Gissar Range, which cantains a lot of large-scale constructions and two Gas field like Aga and Akk.It both have Scientific theory and hydrocarbon exploration meaning to study its Geologic Structure and Hydrocarbon Accumulation Characteristics.This article based on Fault-related-fold and structure restoration theory,combined Drilling Logging and 2D/3D Seismic data to analysis the unconformity feature,divide tectono-stratigraphic sequence,study structure geometry and kinematics style and fracture system features,do structure restoration and analyze formation mechanism.At last,based on Geological structure study we redistrict the Tectonic units and analyze hao the geological structure central hydrocarbon Accumulation.( 1) The study area have the Geologic structure of “ stratification in vertical,zonation horizontally, segmentation in longitude”.In the vertical, it is divided into Basement structure wedge,pre-salt deformable layer,inter-salt deformable layer and sub-salt deformable layer.On the horizontally, it is divided into eastern monoclinal belt, central anticlinal belt and western depression belt from east to west.And the Uzienkuduke strike-slip fault separate it into north and south partitions.We seperate the faults in the area into pre-salt fault system and post-salt fault system by the Gypsolith.The post-salt fault system is priority to normal and strike-slip fault,trending NWW-SEE;the pre-salt fault system is priority to thrust fault, trending NW-SE,control the pre-salt tectonic framework of hollow and long.(2)According to recovery of evolution,Eastern Foreland in Amu Darya Right Bank experienced four major stages:Permian-Triassic transition substrate forming stage,Early-Middle Jurassic rift stage,Late Jurassic to Paleogene depression stage,Neogene-Quaternary uplift stage.The stress action from India-Eurasia collision,Arabic-Eurasia collision and Great Caucasus active expansion in the Neogene effects the structural deformation of the study area.Interference of folding,Gypsum-salt layer regulating effect and lithologic differences between pre-salt and post-salt lead to the tentonic characteristics of “wide-gentle in the post-salt layers and steep-narrow in the pre-salt layers”.( 3) The Jurassic reservoir and caprock configuration is good,Peak oil generation and trap forming time is matching,both lead to the area hydrocarbon enrichment.Hydrocarbon migrate along the thrust fault from the source rocks in profile and differential accumulation in the plane.Combined geological structure, tectonic evolution and petroleum geology features,the study come to a conclution that the serious traps in the western depression belt and central anticlinal belt are favorable hydrocarbon exploration targets.