Abstract: Taibei sag in Turpan-Hami basin is characterized by distinctive structural style and geologic structure based on data from geologic outcrop, seismic profile and drilling-log integrated with thrust plate theoretical analysis. It is suggested that from north to south Taibei sag is divided into wedge-shaped mountain belt, piedmont fault-bench belt, thrust fold belt, sag slope belt and central uplift belt which are distinguished from originally classified north piedmont belt and Shanshan arcuate belt. According to this new understanding,the thrust fold belt and central uplift belt can be subdivided into two branches in east and west trends, with well overlapping in north and south trends, showing stress framework squeezed by thrust orogenic zone and affected by tilting basinal basement fault block since Cenozoic era in Turpan-Hami basin. The burial history and hydrocarbon-generating history of Taibei sag show that two rapid subsiding periods take place,i.e., Middle-Late Jurassic and Miocene-Quaternary. In such a long period of Miocene-Quaternary period lasted long and added the burial depth of source rocks,hence, it was favorable to enormous generation and accumulation of hydrocarbon, and forming configuration with structures in most areas of thrust fold belt. The analysis indicates that sand bodies in lower locations near source sag and shove fault of two rows of piedmont fold belts are more favorable to accumulations of late hydrocarbon reservoirs; while the footwalls of fault-bench belt and central uplift belt are also as targets for exploration.

Key words: Turpan-Hami basin, geological feature, structure, oil and gas accumulation