Abstract:

After setting up recognition marks and boundary confirmation, two first-order and eighteen second-order structural accommodation zones can be identified by using seismic and well data and analysis of fault chara cteristics in K1n stage of the Wuerxun-Beier depression. Four types were determined, including transverse accommodation zones, synthetic overlapping, synthetic approaching, antithetic paralleling. This study results show that along the strike of tensional faults, structural accommodation zones which developed on the weakness zones of the basement, were caused by regional disharmonic extension strain and the model of lateral fault developed. The  “S” plane distribution and structural pattern, migration of subsidence center and thickness of sediments were controlled by structural accommodation zones, most of which are advantageous zones for oil and gas accumulation. Directions of provenance system in secondary depression were controlled by the model of lateral fault, strike ramp, vertical uplift and double direction accommodation.

Key words: Wuerxun-Beier depression, structural accommodation zone, lateral fault, provenance direction