Abstract:

On the basis of the seismic interpretation, the deformation features and evolution periods of inversion structures and their significance on hydrocarbon in the Tazhong-Bachu aera are studied in this paper. The basement normal faults were inversted in the Early and Middle Caledonian and Later Hercynian to Later Yanshanian, respectively. Controlled by the basement normal faults, three styles of inversion structures were developed in Tazhong-Bachu area: (1) Inheritance inversion type. When the dip of the basement normal faults was small, inheritance inversion structures formed by the later inversion acted along the pre-existing normal faults; (2) Short cut type. When the dip of basement normal fault was big, the normal fault might not be favorable for its further inversion and forced the inversion to form in the adjacent faults, and the basement normal faults provided stress concentrations point for the thrust faults, and (3) Reverse cut type. The inversion structures formed by the later thrust faults cut the basement normal faults which have the opposite tendency. The periods of traps formation resulted from structural inversion were greatly match to the peak stages of hydrocarbon generation and expulsion, so inversion structures in the studied area are favorable to hydrocarbon accumulation.

Key words: Tarim Basin, Tazhong uplift, Bachu uplift, inversion structure, evolution model, significance of petroleum geology