TECTONIC EVOLUTION AND HYDROCARBON ACCUMULATION OF THE FIRST AND SECOND ROWS OF STRUCTURE IN THE CENTRAL PART OF SOUTHERN JUNGGAR BASIN

The basin-mountain transition zone has been the focus and difficulty of tectonic geology, thus the analysis of its tectonic style, formation and evolution and accumulation process is of great significance to reveal the reservoir-controlling function of piedmont complex structures and guide oil-gas exploration in basin-mountain transition zone. The tectonic characteristics, evolution process, formation and reservoir-controlling mechanism of the first and second rows of structure in the central part of southern Junggar Basin are studied through the comprehensive application of seismic data interpretation, quantitative analysis of fault activity, and homogenization temperature measurement of fluid inclusion, combined with tectonophysics simulation experiment. The results show that the duplex structure style controlled by basement involvement and caprock detachment fault is mainly developed in the first and second rows of structure. In the Late Jurassic, Qigu-Changji fold belt began to take shape. In the Late Paleogene, Huomatu fold belt was formed. In the Quaternary, the fold belt was intensively transformed by faults to form the fault-fold belt, and the detachment layer played an important role in the transfer of stress into the basin. Multiple sets of source rocks are developed in the central part of southern margin, which formed a multi-stage differential accumulation process with "self-generating and self-storage" and "old-generating and new-storage" as the main combination mode.