Control of petroleum traps by Cenozoic tectonic style in the Liaodong Bay area, of the Bohai Bay basin, China

Abstract

Based on seismic, logging, and drilling data, we analyzed the fault system in the Liaodong Bay area of the Bohai Bay basin, China, and the basin’s evolution. In addition, we studied the local Cenozoic tectonic style, its development, and its effect on hydrocarbon trap. Our results indicate that deformed strata in the Liaodong Bay area are well represented by two layers: a shallow layer (N1g) was deformed by strike-slip and extension, and a deep layer (Eocene) was deformed by extensional effects. The three predominant types of normal faults evident in a transect of the basin are listric fault, variable-dip fault, and straight fault. The local tectonic style consists primarily of extensional, compressional, and strike-slip structures. The extensional structures developed primarily during the syn-uplift stage and affected the lower strata. The strike-slip structures developed primarily in the post-uplift stage and affected the upper strata. The inverted structures are rare, developed primarily during the transitional period, and affected the upper-middle strata. Traps formed by the extensional structures are primarily of the ancient buried hill, anticline/half-anticline, and fault-block types. Traps formed by the strike-slip structures are primarily of the fault-block and anticlinal/half-anticlinal types.