沾化凹陷三合村洼陷油气多期成藏过程研究

利用钻井、测井以及分析化验等资料,基于沉积埋藏史和生烃史研究,结合油气来源,分析沾化凹陷三合村洼陷油气成藏过程。结果显示:三合村洼陷存在3种原油类型,油气主要来自于渤南洼陷,油气成藏经历了东营组成藏期、馆陶组成藏期和明化镇组成藏期3期成藏;东营组成藏期形成的油藏原油源于沙四上亚段成熟烃源岩,此时垦西低凸起还未成型,来自渤南洼陷的油气以断裂侧向-不整合型二元输导体系沿斜坡带运移至三合村洼陷沙三段及以下地层中成藏,并在后期由于硫化作用和生物降解作用发生稠化;馆陶组成藏期形成的油藏原油源于沙四上亚段和沙三段烃源岩,此时垦西低凸起已成型,来自渤南洼陷的油气主要以网毯模式运移至沙三段以上地层中,在后期发生生物降解作用而稠化;明化镇组成藏期形成的油藏原油源于沙三段成熟烃源岩,同样以网毯模式运移至三合村洼陷,主要在新近系成藏。

Study on multi-period hydrocarbon accumulation process in Sanhecun subsag of Zhanhua sag

The dynamic process of hydrocarbon accumulation in Sanhecun subsag of Zhanhua sag was studied by analyzing the sedimentary burial history and hydrocarbon generation history, taking advantage of the abundant drillings and available test datum. The results show that the crude oil in Sanhecun subsag originated from Bonan subsag, and the crude oil can be classified into three different types. The three stages of evolution in the hydrocarbon accumulation include the Ed formation, the Ng formation and the Nm formation, respectively. The crude oil of reservoirs formed in the Ed formation originated from the matured source rocks of Es₄ before the formation of the Kenxi low uplift. The crude oil from Bonan subsag migrated along the slope through fault-unconformity carrier system to Sanhecun subsag and was accumulated in the Es₃ and the following strata. The reservoirs formed at this stage were thickened by curing and biodegradation in the later stage. The crude oil of reservoirs formed in the Ng formation originated from the source rocks of Es₃ and Es₄ after the formation of the Kenxi low uplift. The crude oil from Bonan subsag migrated along the meshwork-carpet system to Sanhecun subsag and accumulated above the Es₃, and the reservoirs formed at this stage were thickened by biodegradation in the later stage. The crude oil of reservoirs formed in the Ng formation originated from the source rocks of Es₃, and the crude oil also migrated through the meshwork-carpet system and accumulated in the Neogene.