中国中西部前陆盆地油气分布控制因素

从中国中西部前陆盆地类型、构造单元和构造带3个层次深入分析控制油气分布的主要因素。中国中西部主要发育叠加型、改造型、早衰型和新生型4种前陆盆地,其油气成藏条件、成藏特征与油气聚集模式决定了不同类型前陆盆地油气分布的差异。前陆盆地发育冲断带、前渊、斜坡带和隆起带等构造单元,不同构造单元在烃源岩发育与演化、圈闭类型及成藏过程、保存条件等方面的差异导致不同构造单元油气分布特征的差异。前陆冲断带是中西部前陆盆地油气富集的主要构造单元,烃源岩与储盖组合、构造特征及保存条件是其油气聚集成藏的主控因素,冲断带断层、盖层的时空配置控制了油气分布的分带、分段特征和富集规律,指示着不同构造段的油气富集部位及有利勘探目标。

The hydrocarbon distribution characteristics under the control of basin type, structural unit and thrust belts in the foreland basins, central and western China

Three-classes analyzing, including the types of foreland basin, structural units and structural belts, would offer extensive knowledge of differential hydrocarbon distribution and be important to oil and gas exploration in the foreland basins of central and western China. There developed four types of foreland basins in China, named the superimposed, the presenile, the reconstructed and the new-generated foreland basin. Hydrocarbon distribution was different in the four types of basins according to their respective hydrocarbon accumulation conditions, characteristics and patterns. The different characteristics of structural belts in foreland basin, including source rock development and evolution, trap type, hydrocarbon accumulation process and preservation condition, play a controlling role in hydrocarbon distribution. The main hydrocarbon enriched structural units are the foreland thrust belts, in which the structural styles, tectonic evolution and the preservation of regional caprock are the critical factor of hydrocarbon accumulation. The hydrocarbon distribution in foreland thrust belts are characterized by obvious segmentation.