陆相断陷盆地洼槽聚油理论及其应用——以渤海湾盆地冀中坳陷和二连盆地为例

陆相断陷盆地洼槽区通常被当作生、排烃区而非油气成藏区，故在被证实具有生排烃能力之后，往往被以寻找油气藏为主的勘探工作所忽视。依据渤海湾盆地冀中坳陷古近系和二连盆地白垩系多年油气勘探实践，提出了陆相断陷盆地洼槽区多元控砂、优势成藏、主洼槽控制油气分布、三主元因素控制油气规模富集、构造油气藏与地层-岩性油气藏具共生互补性等洼槽聚油新认识，指出洼槽区反转构造带翼部扇三角洲前缘、缓坡坡折带三角洲前缘、湖底扇、断层根部河道砂等是形成规模富集地层-岩性油气藏的有利场所和勘探的有利方向。应用这一理论，华北油田在断陷盆地洼槽区发现了数亿吨石油地质储量。

Theory of hydrocarbon accumulation in troughs within continental faulted basins and its application:A case study in Jizhong Depression and Erlian Basin

Troughs in faulted basins are generally taken as a province of hydrocarbon generation and expulsion instead of accumulation. Therefore, troughs are frequently neglected in the exploration focusing on the search of hydrocarbon reservoirs provided that they have been verified to be of hydrocarbon generation and expulsion capacity. Based on the practical exploration in Paleogene of Jizhong Depression and Cretaceous of Erlian Basin for years, this paper puts forward a new concept on the hydrocarbon accumulation in troughs of faulted depressions, which includs the following findings. In troughs of faulted basins, the sandbody distribution is controlled by multiple factors, lithologic accumulations are more readily to form than structural accumulations, three factors control the formation of large hydrocarbon accumulations, and structural and stratigraphic-lithological reservoirs are not only co-exist but also complement each other. Moreover, the novel concept also indicated that in troughs, fan-delta front in a flank part of an inverted structural belt, delta front on the break of a gentle slope, a sublacustrine fan and a channel sandbody along toes of faults are favorable locations for hydrocarbon accumulations in stratigraphic-lithologic traps. With the application of this concept, hundreds of million tons of oil reserves have been discovered in trough areas of the Huabei Oilfield.