Structural Characteristics And Hydrocarbon Accumulation In Bashituo Area,Tarim Basin

The Bashito oil and gas reservoir has experienced multiple periods of tectonic movement during its formation and evolution,which leads to a close relationship between the formation of oil and gas reservoirs and the structural characteristics of different periods of tectonic movement and its formation.This article takes the Bashto region as the research object,and uses modern structural geology,structural analysis theories and methods,faults and related fold theories,and layer flattening techniques as means to analyze the faults,fractures and structural characteristics of the Bashto region.The study of evolution characteristics analyzes and discusses related controversial issues such as the time and type of oil and gas accumulation in the study area,oil and gas migration channels,and whether it contains paleo-oil reservoirs,and analyzes its significance for oil and gas exploration from the perspective of oil and gas accumulation..The main knowledge gained are:(1)The study area has experienced three phases of tectonic movement from the Carboniferous to the Upper Tertiary: the end Permian tectonic movement(late Hercynian),the early Himalaya tectonic movement,and the late Himalaya tectonic movement.The tectonic movement at the end of the Permian is an important period for the formation of traps.The main period for the formation of folds and the development period of large reverse faults,from the lower fault to the top of the Permian,are also the main periods for the formation of fractures.The early Himalayan tectonic movement superimposed and reformed the traps formed by the early tectonic movement.The Bashtop reverse fault had a greater impact on the tectonic movement during this period.It reactivated,and the structural shape and trap did not change much.The Bashto area has been reformed more strongly,and the reverse fault has been revived to the bottom strata of the Tertiary.In the late Himalayan tectonic movement,the structural changes were small,the folds were small,the faults were basically not developed,and the lower faults were not activated.(2)Affected by the Bashtou fault and its derivative fractures,the Bashtopu reverse fault was revived during the early tectonic movement in the Himalayas and cut through the lower tertiary strata.After the end of the early tectonic movement in the Himalayan period,the main controlling fault and its associated faults have ceased to operate and cannot be used as a vertical migration channel for oil and gas.The oil and gas migrated horizontally along the sand bodies in the Bachu Formation and accumulated in the Carboniferous.(3)The late Hercynian tectonic movement has strong folds and developed faults.There is no oil and gas display in the Permian strata,and no heavy oil and asphalt have been found in the Carboniferous.Therefore,there is no paleo-oil reservoir in the Permian period in this area.