Tectonic Evolution And It'scontrol On Hydrocarbon Accumulation Of Western Segment Of The North-tarim Uplift

The tectonic activities are strong and the erosion is serious in Wensu-Yingmaili areas of western segment of North-Tarim uplift.There are different interpretative versions caused by limited seismic data quality and still needed further study.Previous studies are mainly focused on the middle and shallow order,lack of the understands of the deep structure,and now the previous study still stay in the qualitative stage,lack of quantitative analysis.Because of the characteristics of multi-stage tectonic of North-Tarim uplift,the unconformity can indicate a tectonic activity,and the identification of unconformity can help to determine the mechanism of its fracture generation.The previous research on this aspect is relatively weak.The purpose of this paper is to use the latest 2D seismic data,exploration stratification,logging data and geological map to analyze the tectonic-stratigraphic sequence,unconformities features,fracture system development history and distribution characteristics in the western segment of the North-Tarim uplift;and to establish a large section of geometry and kinematics of the northern piedmont belt,in order to analyze the key structure such as Karayulgun fault zone(including Shengli-Sixteen field),Shajingzi fault zone,Yangdake-Yingmai7 fault zone.Based above,discussion the control of deep faults to shallow layer,using balance-section to construct the tectonic inversion,and finally the control effect of the structure and tectonic evolution on oil and gas accumulation is analyzed in the western segment of the North-Tarim uplift,to provide reference for oil and gas exploration.The main achievement and knowledge are as follows:(1)The western segment of the North-Tarim uplift is overlaid by a multi-stage structure,the tectonic activity is very complicated and the erosion of the strata is very serious,the Paleozoic strata were denuded by a large scale north to the Kuqa area.(2)The Shajingzi fault zone is the boundary between the Kuqa and the Avati depression,according to the seismic interpretation,The Shajingzi fault zone is composed of three faults,the main fault named ShaJingZi1 has the nature of the shear of the fault triangle,early basement faulting caused a rise in Paleozoic strata,Wensu bulge began to form.The Shajingzi fault zone was thrusted and reformed on the foundation and then formed the present tectonic feature.(3)The Karayulgun fault zone is located on the boundary between the North-Tarim uplift and the Kuqa depression,which is characterized by the obvious upper and lower layers.The underlying huge basement trust faults are obviously characterized by significant periods of activity.(4)The layer of the salt rock of the Paleogene and middle Cambrian developed in the Yangdake-Yingmai7 fault zone.These two detachment layer control the tectonic deformation in the region,to make it generated that the structural features of the layered deformation of above salt and under salt.(5)The oil-gas accumulation formation in western segment of the North-Tarim uplift has the characteristics of sea continental oil source intersection,and has many good source-reservoir-cap combinations.Overlay structure played an important role in oil-gas accumulation in the western segment of North-Tarim uplift.Through the analysis on the Shajingzi fault zone and oil-gas migration and accumulation of Yangdake-Yingmaili area,the unconformities and faults are the main path-way for hydrocarbon migration,and they can effectively communicate the source and they are good for the long distance migration of oil and gas.