Study Of The Relationship Between Characteristics Of Fault Structural Styles And Oil-Gas Accumulation In Bachu Area Of Tarim Basin

Based on the 2D seismic survey line and oil-gas exploration achievement in Bachu area of Tarim Basin, and taking the theory and technique of petroleum tectonics analysis as a guide, through the interpretation and mapping of fault structural style, combined with the research of balanced geological cross-section and literature in oil-gas accumulation conditions and reservoir characteristics, the regional tectonic framework, fault structural styles and structural evolution characteristics are analyzed in Bachu area. Through the analysis of typical oil-gas reservoirs and drilling failure, the control effect of oil-gas aggregation by fault structural styles and structural evolution characteristics can be concluded.The Bachu uplift has a complicated fault system in Tarim Basin, "west-east orientation and north-south division" is the unique characteristic of regional tectonic framework. The region has formed a complex superimposed structural style with high angle basement-involved type fault, combined with capping-sliding type compresso-shear fault by the multi-period tectonic stress effect including Caledonian, Hercynian, Indosinian-Yanshan and Himalaya. Combined with the change of sedimentary environment, stratigraphic distribution, lithological association, the reflection characteristics of seismic profiles and tectonic deformation features, Bachu uplift can be divided into 6 first-class structural sequences, corresponding to the major faulting period of early Caledonian, middle Caledonian, early Hercynian, later Hercynian, Indosinian-Yanshanian and Himalayan. Early Caledonian is the initial active stage of fault zone, later Hercynian and Himalayan are intense active stage, and faults generally experience the evolution process of tensile after compressive.Through the analysis of typical oil-gas reservoirs and drilling failure in the study area and adjacent regions, we can conclude that the complexity of the oil-gas accumulation is caused by the complexity of tectonic movements of Bachu uplift. Reservoir-forming assemblage controls the distribution of oil-gas reservoirs, preservation condition of traps control the scale of reservoirs, both of them play a leading role in oil-gas accumulations. The most favorable tectonic belts in Bachu area mainly includes Yasundi secondary structural belt, Haimi-luosi tectonic belt, Niaoshan tectonic belt, Mazha-tage tectonic belt, the exploration targets are Cambrian System-Ordovician System, Upper Devonian System and Carboniferous System, respectively; exploration targets of Bashituo-Xianbazha tectonic belt are Carboniferous System and Cambrian System-Ordovician System.