Analysis On The Structural Characteristics Of The Middle Permian In The Shuangyushi-Zhongba Area In The Piedmont Of The Longmen Mountains

Longmen mountains tectonic belt is an experienced many times,multilevel tectonic movement of the typical intracontinent collision orogen belt with complex geological evolution history and strong tectonic activities.Based on the sufficient study the zoning of Longmen Mts structural belt,by using the drilling and logging data,the high quality of 2D and 3D seismic data,the tectonic pattern of Longmen Mts piedmont belt in the study area has been determined.Taking No.? fault as the boundary,it can be divided into Longmen Mts over thrust nappe belt and back thrust anticline belt.According to the research of tectonic pattern,we ascertained several rows of structural belts developed in Permian formations in back thrust anticline belt of Longmen Mts.piedmont belt.The comprehensive interpretation technology of seismic and geological,combing geological Hat technique,and Drilling geological recovery technique and geological model forward modeling technique would be favorable to improve the interpretation accuracy for structural pattern of complex structural belt.The distributive characteristics of the faults and structure in the plane as well as the section have been figured out.Studies show that the fault of back thrust anticline belt controlled the terrain background,the oil-gas distribution and the formation of the stratigraphic-structural composite trap.The structure of back thrust anticline belt has a trend from northeast to southwest,which is gradually converged toward the footwall of No.? fault in the south.SJH-TZG tectonic belt takes No.? fault as a boundary in northwest,and is bounded by No.? fault in southeast,which is gradually narrowed toward southwest and finally missing in the footwall of No.?fault.SYS-ZB tectonic belt is bounded by No.?fault and the sag of No.? fault footwall.There are multiple anticline with great exploration value and fault block structures in the SYS-ZB tectonic belt.Base on the tentonic characteristics and tectonic evolution study,neopaleozoic petroleum system has excellent conditions for reservoir accumulation,with lower Cambrian and Silurian high quality hydrocarbon source layers developed.And tectonic deformation characteristics formed by Longmen Mts napping has created excellent hydrocarbon source fractures and sealing conditions for hydrocarbon accumulation,which would be beneficial for the formation of giant gas accumulating area.Research suggests that the zone between the No.? fault and the eastern boundary of Middle Permian Qixia formation's favorable facies belt is the favorable area for further exploration.