沾化凹陷富林洼陷中次洼纵向油气不均匀富集及控制因素

THE CONTROLLING FACTORS OF UNEVEN VERTICAL ENRICHMENT OF HYDROCARBON IN THE CENTRAL SUB-SAG OF FULIN SAG OF ZHANHUA DEPRESSION

沾化凹陷富林洼陷中次洼靠近垦利断裂带的区域纵向上油气富集存在不均匀性,通过烃源岩生烃演化分析、油源对比、断层活动性分析等方法分析了研究区的油气成藏特征和影响因素,结果表明:富林洼陷中次洼靠近垦利断裂带的区域深层沙三段储层和浅层东营组、馆下段储层均发现油藏,而中部沙二段和沙一段的圈闭大多为空。造成这种油气不均匀富集的因素为深层沙三段油藏中的油气来源于中次洼沙三下亚段烃源岩,而浅层东营组和馆下段油藏中的油气来源于孤南洼陷沙三下亚段烃源岩;富林洼陷油气来源有限,且烃源岩排烃期与垦利断层活动期配置不佳,油气输导条件受到限制,只能短距离运移在沙三段储层聚集;孤南洼陷油气来源充足,且烃源岩在大量排烃时期、垦利断层处在活动期,且能够输导油气,因此油气能够远距离地运移到富林中次洼的浅层东营组和馆下段聚集。

In the area near the Kenli fault in the Central Sub-sag of the Fulin Sag, there occurs uneven hydrocarbon vertical distribution. Hydrocarbon accumulations have been found in the deep layer of Es3 and the shallow layers of Ed and Ngx, while the traps in the middle layers Es2 and Esl are mostly empty. Based on oil-source correlation, source rock hydrocarbon-generating evolution analysis, fault activity analysis and other kinds of methods, we studied the characteristics of hydrocarbon accumula- tion and controlling factors. Results show that the hydrocarbon in the reservoirs of Es3 is from the Es3xsource rocks of the Central Sub-sag in the Fulin Sag while the hydrocarbon in Ed and Ngx reser- voirs comes from Es3xsource rocks in the Gunan sag. The hydrocarbon from the Fulin Sag is limited, and the migration conditions are restricted since the hydrocarbon-expulsion period of the source rock did not match the active period of the Kenli fault. Therefore, the hydrocarbon can only migrate for a short distance and accumulate in the reservoirs of Es3. However, the hydrocarbon from source rocks of the Gunan Sag was sufficient, and the Kenli fault was active during the hydrocarbon-expulsion peri- od of the source rock, so the hydrocarbon is able to migrate through the fault for a long distance and accumulate in the Ed and Ngx in the Central Sub-sag of Fulin Sag.