Structural styles and hydrocarbon accumulation of the northern piedmont belt in the Taibei Sag, Turpan-Hami Basin

The northern piedmont belt of the Taibei Sag is one of the oil rich structural belts in the Turpan-Hami Basin. Based on the interpretation of seismic cross sections and the analyses of discovered hydrocarbon accumulations, the geologic structure can be divided into six structural styles, thrust-imbricate structure, imbricate fan structure, thrust-opposite structure, pop-up structure, forward thrust structure and duplex structure. According to the study of the distribution regularity of the structural styles, the fold thrust belt controlled by three levels tectonic transform zones is characterized by zonation from the south to the north and segmentation from the west to the east, and it can be classified into thrust-nappe belt, breaking belt and frontal belt by mechanism of tectonic deformation. The leading edge with two accumulation forming models which are the leading edge pop-up model and the leading edge imbricate fan model is the most favorable hydrocarbon enriched belt in the northern margin of the Taibei Sag. The thrust-opposite structures in the rear edge of the deformable zone have good preservation, potential source kitchen on the footwall, higher fault dip, and good communication of sandbodies. They are the next favorable exploration structures. Key words: structural style, thrust faults system, structural deformation belt, tectonic transform zone, accumulation forming mode