An Analysis of the Conditions for the Formation of Oil and Gas Accumulations in Northern Gaosheng Area within the Western Depression of Liaohe Sag
辽河坳陷西部凹陷高升北部地区古近系油气成藏条件分析

The northern Gaosheng area is a prolific zone for petroleum accumulation in Bohai Bay Basin. An analysis of the petroleum accumulation in this area is therefore of great significance in the correct understanding of the conditions and the model for petroleum accumulation. The formation, migration and accumulation regularities of petroleum in northern Gaosheng area were studied by using integrated geological, geophysical and geochemical methods and computer techniques. It is shown that there exist favorable conditions for the formation of the hydrocarbon reservoir, and that the hydrocarbon source rock has passed through the evolution of the organic matter from low maturity to maturity. Sand bodies in the delta front are the most important oil and gas reservoir. The favorable developing area of the reservoir is located at Gao 88-Gao 70 wells belt in the southern part. The maturity of the organic matter and the developing area of the reservoir in northern Gaosheng constitute the most important factors for the formation of the oil and gas accumulation.