Abstract: Several big oil-gas reservoirs,with reserves of 100 million tons more,have been discovered in the Upper Tertiary middle and shallow strata of Bozhong area in Bohai Bay since last five years, as a result,the area became the hot-point area followed with interest by domestic and abroad oil men. Bozhong area has different oil-gas accumulation characteristics from the adjacent onshore oil fields. Because of the latter thermal event and tectonic action,Bozhong area became the subsidence center and depo-center of the Bohai Bay Basin. There is better reservoir-seal formation which is superior to the adjacent oil field onshore,the latter fault action timing with the big scale hydrocarbon migration provided the favorable conditions for oil-gas migration and accumulation toward Upper Tertiary trap. Many kinds of reservoir-forming model created many kinds of oil-gas reservoir,two kinds of fault structural system and the tectonic framework of horst-graben interval are favorable of the oil-gas rich accumulation toward middle-shallow strata and uplift area. Therefore the Upper Tertiary middle and shallow strata are major exploration zone.

Key words: Bozhong Depression, thermal subsidence, middle-shallow strata reservoir, oil-gas accumulation

摘要： 渤中坳陷近5年来先后于中浅层的上第三系发现了多个储量超亿吨的大型油气田,成为国内外石油界关注的重点和热点地区。其具有不同于周边陆地油田的油气成藏特点,晚期的热沉降和构造活动使其成为渤海湾盆地的沉降和沉积中心,上第三系具有优于周边陆地油田的良好的储盖条件,晚期的构造活动与油气主要排烃期相匹配,为油气向上第三系圈闭中运聚提供了良好条件。同时,两种断裂系统、垒堑相间的构造格局、晚期油气运移的多样性造就了渤中坳陷上第三系丰富多彩的油气藏类型和大规模的油气聚集。

关键词: 渤中坳陷, 热沉降, 中浅层油气藏, 油气聚集