The Research On Structural Style And Its Effects On Hydrocarbon Accumulation In Hashan Area,the NW Margin Of Junggar Basin

Hashan(Hala'alat mountain)thrust belt,a part of late Paleozoic fold mountains in the NW margin of Junggar Basin.Its complicated geologic structure take a significant restriction of exploration process in this area.In order to figure out the effect of tectonism on hydrocarbon accumulation,we take large number of 3D seismic data and logging data to identify the fracture system and set up the model of structural interpretation.According to regional unconformity,fault activity and tectonic deformation recovery analysis,combine with the former research to analyze the tectonism on hydrocarbon accumulation.Three conclusions drawn in this paper are as follows:(1)Hashan area developed NE,NW,near EW trend major fault include strike-slip,compression and tensional fault.The compression fault have 3 types,high angle thrust,low angle over thrust and recoil.The structural style have three types of ten small classes.Establish the interpretation model of Hashan area,thrust nappe superimposed and later strike-slip.The old and new strata reversed and six periods of thrust nappe developed in the study area.The structural layers divided into 3.Upper layer,Jurassic and Cretaceous formation monocline overlap the main part of Hashan.Middle layer,Permian and Triassic is serious deformation.The lower layer,Permian and Carboniferous formation slippage in its place.It's divided into three structural deformation belts in plane which are reworked strike slip tectonic zone in the north,nappe superimposed-imbricate thrust tectonic zone in the central,and the low angle overthrust-thrust tectonic zone in the south.It develops overlying multistage thrust nappe of the Lower Permian and the Carboniferous in western segment,and overlying imbricate thrust of Triassic and Permian in eastern segment.(2)Impactef by hercynian,indosinian and yanshan movement,d five regional unconformity has been evelopmented,by the analysis of unconformity styles,fault cutting relationsand the angle of axial planes of the structures,it's divided into five stages of tectonic movements,the structural evolution of Hashan structural belt since late Paleozoic is rebuilt,which could be divided to five phases:late of Early Permian imbricate thrust phase,Late Permian para-foreland basin intensive nappe thrust-adjusted strikeslip phase,Triassicintra continental basin inherited nappe thrust-resformed strike slip phase,Jurassic and Cretaceous intracontinental basin vibrated uplift phase and Neogene-Quaternary foreland basin and Himalayan strike slip phase,The tectonic style of different evolution stages has a difference.(3)Based on the structural characteristics and tectonic deformation recovery research,combined with the feature of accumulation analysis,shows that and as a result,resource rock is developed broadly,which is distributed in several building blocks controlled by the overthrust belt and enhance the potential of hydrocarbon resource evaluation.The physical properties of brittle volcanic-dolomitic reservoir are improved due to the fault-microfracture associated with tectonic activities and uplift-erosion weathering.Tectonic style types control the development of structural trap types,mainly for anticline,faulted anticline traps in the west and the east are mainly fault block,broken nose,The factors of source rocks and reservoirs control the reservoir types,also,the preserve condition control the difference of oil-gas pool characteristics.It finally form the hydrocarbon distribution patterns of the symbiotic of low mature,immature and high mature oil,and the coexistence of light and heavy oil.