Characteristics of petroleum geology in South Poyang Depression

The South Poyang depression is an overlay basin formed by the Mesozoic-Cenozoic continental basin and the Paleozoic-Mesozoic marine-transitional basin, characterized by upper tensile structure and lower compressive structure. The Jiuling Nappe (slide) System in lower tectonic layer overrides (slides) from north toward middle-south part of the depression, while Guanmaoshan overthrust system moved to north forms a ramping front belt which is a favorable zone for petroleum exploration conserved in Permian. The evolution of the Mesozoic-Cenozoic basin is controlled by the paleo-tectonic framework and Ganjiang faulting belt in the mid-episode of Yanshan movement. The source rocks are developed in Permian, and the bark-like coal of Longtan formation (P2l) belongs to a high quality of coal-derived-oil source rock, with multiple types of traps dominated by block structural traps and sandstone lithologic traps in the depression. It is concluded that the most favorable type of hydrocarbon accumulation is the complex lithologic-structural trap with both source and reservoir in Longtan formation that underwent the secondary hydrocarbon generation and late-stage hydrocarbon accumulation in the depression.