The Styles And Evolution Of Longmen Shan Anterior Margin

Longmen Shan anterior margin is located at western of Sichuan basin . Longmen shan fold and thrust belt and the western Sichuan foreland basin lies to the tectonics belt. Longmen Shan anterior margin is the combine unit of the coupling of basin and mountain system . the strcture is complicated and changeful . The tectonic cortroling factor is varyed in differ belt . This thesis studyed the tectonic geometry and kinematics and kinetics of Longmen Shan and discussed the tecnotic style and evolution and the dynamic model ant its simulation on the foreland of Longmen Mountain . The paper discuss those factors and their influence on the oil-gas formation . At last, on the base of the analyse about history of reservoirs formation, forecast reservoirs pattern, point out favored oil and gas bearing structure and the target. And obtain some important conclusion.The progressive thrusting and nipping of Sichuan fole-thrust belt controlled the distribution and develoment of the the main styles in the Sichuan foreland basin.While it shows a zonality in plane,vertically the structual deformation appears in different levels . In plane it can be devided in to deep-seated level; middle seated level; upper-seated level.The main structural types consist of basement thrust and nappe ;imbricate thrust system , klippe, duplex,pop-up,triangle zone .fault-propagation fault-bend and gentle fold ,etc. tecnotic styles have their own character of gathering oil and gas .While Fault-propagation fold present 'Y', this style is goog at keeping oil and gas . when the fault present twin in two way ,they are better at keeping oil and gas.In order to furtherly study the petroleum accumulation law,this paper ,based on the tectonic evolution , started from main hydrocarbon generation periods of the main resource rock, analysed petroleum generation ,migration ,accumulation,adjustment and dynamic accumulation process . There are several tecnotic stage:the Carian stage,the Norian stage, Indo-china movement yanshan epoch ,hymalayan orogeny epoch etc.In thoes epoch, indo-china movement and hymolayan movement are the key tectonic movements on the form of foreland basin.Yanshan movement control the sediment. The hymalayan movemet determined the preservation of oil and gas. From coupling of basin and mountain system,Indo-China movement, norst-western of Longmen Shan anterior margin is the front-mountain belt .and hymalayan orogeny epoch, Longmen Shan rise,the foreland basin shape .Early accumulation and later seal is the the basic character of gas resevoirs in Longmen Shan anterior margin.Dayuanbao trap and Dayi trap,and Yazihe Trao etc are fovorable struture .