Structural evolution and sub-secondary tectonic units division of northeast margin in Wuwei Depression, the Lower Yangtze region

Due to the complex tectonic of the Lower Yangtze region, oil and gas exploration in the Mesozoic and Paleozoic strata have not been achieved with significant breakthrough. As the advancement of the oil and gas exploration revealed enormous potential for shale gas on the northeast margin of the Wuwei Depression, it’s urgent to delineate sub-level tectonic units. Through 2D seismic and other geological works on the northeast edge of the Wuwei Depression, the deep stratigraphic geological structure was preliminarily determined. Based on faults and structural contour lines, six sub-secondary tectonic units were delineated. Combined with geological data, the tectonic evolutionary stages of the Wuwei Basin are analyzed. Research indicates that the northeast margin of the Wuwei Depression has generally undergone stable oscillation, compressional thrust, and extensional rifting periods, overall presenting a structural pattern of “two depressions sandwich one uplift”. This study will provide technical support for the subsequent fine oil and gas exploration in the Wuwei Depression.