Organic-matter maturation and petroleum generation model in the Yinggehai and Qiongdongnan basins

<正> The enhancement of organic-matter maturation and petroleum generation by the migration and accumulation of active hydrothermal fluids in the high thermal-gradient, strongly overpressured environments in the Yinggehai and Qiongdongnan basins is systematically demonstrated by combination of geological, geochemical analysis and basin modeling. The retardation of organic-matter thermal evolution by abnormal pore-pressure is recognized, its manifestation and dynamic mechanism are illustrated, and chemical kinetic modeling of the pressure retardation is carried out. On this basis, the model of organic-matter thermal evolution and petroleum generation in high thermal-gradient, strongly overpressured environments is summarized. A correct understanding of the effects of active hydrothermal fluids and abnormal pore-fluid pressures on organic-matter thermal evolution is of great theoretical and practical significance for thermal history analysis, basin modeling and petroleum resource evaluation.