The Origin of Complex Geological Structure and Main Controlling Factors of Hydrocarbon Accumulation in D Sub-sag of Weixi'nan Sag

D sub-sag is another proven hydrocarbon-rich sub-sag in Weixi'nan Sag, but its geological structure is complex. The understanding of genetic evolution law and the enrichment regularity of oil and gas accumulation directly affect the guidance of the next exploration practice. Based on the analysis of the geological structure of D Sub-sag, this paper analyzes the regional tectonic movement and stress evolution mechanism, and clarifies the differences of fault evolution characteristics and main controlling and enrichment factors of oil and gas accumulation in different tectonic units. It is considered that the paleo-uplift background and the transporting and sealing of faults and sand bodies are the main controlling factors of oil and gas accumulation in Weizhou Formation of W oilfield. Furthermore, it is pointed out that the mild slope zone and steep slope zone of D Sub-sag are favorable areas for oil exploration in Weizhou Formation and Liushagang Formation, while the trough zone has exploration potential for subtle oil and shale oil. The study has great guiding significance for the next research and exploration direction selection.