Study On Tectonic Deformation Features Of Marine Strata And Its Petroleum Geological Significance In Jianghan Plain

Structure is the key to restrict hydrocarbon accumulation.There is a structural styles of various cause and the oil and gas reservoir of complex reservoir-forming rule,because of the multi-stage basin evolution and the multi-stagetectonic movement resulted in the complexity of oil gas evolution in Mesozoic and Paleozoic in the Jianghan Plain,and it effect on the Oil and gas exploration in this area.On the Basis of seismic,logging,drilling data and field outcrop data,the study,which is guided by tectono geology,tectonic geochronology,geodynamics and foreland thrust belt theory,apply the balanced geological section technology and the advanced seismic interpretation technology which is applied to complex fault zone to establishing the texture and structure model of Jianghan plain.Besides,for the comprehensive analysis of the relationship between structural deformation and oil and gas preservation,the research also systematically has illustrated textural characteristics and tectonic deformation features,and contrasted the difference of tectonic deformation between the two sets of tectonic systems,and it's can provide theoretical basis for oil and gas exploration in this area.On the basis of fine seismic data interpretation,Jianghan Plain and its surrounding areas by the analysis of structural features is formed in the Qinling-Dabie tectonic belt and Jiangnan-Xuefeng tectonic belt under the action of two opposite extrusion.Since the Indosinian period,tectonic evolution and tectonic framework of Jianghan Plain both in the northern Qinling-Dabie orogenic belt and the southern Jiangnan-Xuefeng orogenic belt joint function of restriction,makes the Jianghan Plain in forming the composite joint pattern of multiple tectonic system.According to the structural deformation characteristics and structural forms of the study area,the Jianghan Plain can be divided into three tectonic zones: the southern tectonic zone,the northern tectonic zone and the North-South hedging interference zone,these zone can further organised into 9 three tectonic units.And both Dangyang depression belt and the Jingzhou Mianyang hedging interference zone can be divided into two four structural units respectively.Bassed on the characteristics of the mechanical properties of structural deformation,the mode of stress transfer and the geometric style,the structural styles of the study area are divided into three categories,namely,squeezing contraction structure,strike slip and compression torsion structure,extensional inversion type structure.The spatial distribution of fault in the study area is divided into three systems: NNW or NW direction,NE or NEE direction and near EW direction,which are affected by the joint effect of Jiangnan-Xuefeng orogenic belt and Qinling-Dabie tectonic belt,and the tectonic evolution process of different distribution directions is also different.By specific analysis of the boundary conditions such as the Qinling-Dabie tectonic belt,the Jiangnan-Xuefeng orogenic belt and the Huangling uplift,the Mesozoic and Cenozoic tectonic evolution in the Jianghan plain area can be divided into Caledonian Hercynian,early Yanshan,late Yanshan and early Himalayan periods,combining regional stratigraphic unconformity contact relationship,tectonic stress field evolution,seismic tectonic analysis and balanced section technique.There are four periods in the late Himalayan period,and the early Yanshan period can be divided into three episodes.The structural pattern controls the accumulation and preservation of oil and gas.By comprehensive analysis both evolution history and tectonic deformation features of different structural belts,It is considered that the Yichang stable zone and the early Western Dangyang fold belt are located in the paleo uplift and the periphery in the early stage.The current structure is relatively stable,the deformation is weak,the local structure is more developed,the preservation is better,and it is a favorable exploration zone.