济阳坳陷南部油气成藏特征对比分析

Petroleum accumulation and occurrence in the Dongying and the Huimin Sags

济阳坳陷南部的东营凹陷与惠民凹陷相邻 ,成藏条件与油气富集特征既有相似性 ,又存在较大差异。东营凹陷与惠民凹陷主力生、储油层系的岩性、层位基本相同 ,圈闭及油气藏类型相似 ,均具有两期成藏并以晚期成藏为主的特点 ,均在凹陷中央形成中央隆起带 ,并成为油气富集区带。东营凹陷与惠民凹陷面积相近 ,但油气丰度悬殊 ,东营凹陷探明储量大体为惠民凹陷的 7倍 ,其主要原因是虽然凹陷内部均发育多个次级洼陷 ,但洼陷的演化历史存在较大差异 ,尤其是惠民凹陷只有南部临南洼陷是继承性发育的深洼陷 ,其它洼陷在古近纪后期沉降缓慢 ,大大影响了有机质的成熟进程。凹陷沉降演化史不仅控制了烃源岩有机质的成熟演化 ,对储盖条件也有重要影响。图 4表 1参

The conditions and characteristics of petroleum accumulations in the Dongying and the Huimin Sags in the south of the Jiyang Depression have certain resemblances, but still have a great difference. The lithology and geological ages of the major source rocks and reservoir rocks are basically uniform, and the types of traps and reservoirs are also similar in these two sags. Petroleum accumulation has two stages, and the later stage is the dominant one.The oil and gas are rich in each of the two sags of the central uplift belt. There is great difference in the petroleum richness for the two sags in despite of the similar acreage, and the provon reserves in the Dongying Sag is about seven times of that in the Huimin Sag. The main factors caused this big difference and greatly affected the maturity of organic matter are the different evolution processes in the sub sags. In Huimin Sag, only the development of the Linnan Sub sag is successional, and the others subsided slowly in the later Paleogene period. The subsidence history of the sags has not only controlled the maturation of organic matter of the hydrocarbon source rocks, but also influenced the reservoir and capping conditions greatly.