济阳坳陷浅层次生气藏与稠油油藏的关系

Discussion on the relationship between shallow secondary gas reservoir and heavy oil reservoir in Jiyang depression

济阳坳陷浅层次生气藏及稠油油藏主要分布于生油洼陷的周缘、凸起带及中央隆起带。以济阳坳陷地质、地球化学研究为基础,从浅层次生气藏来源、浅层油气成因、稠油稠化原因、天然气运聚动平衡、浅层次生气藏与稠油油藏分布规律等方面,探讨济阳坳陷浅层次生气藏与稠油油藏的关系。研究结果表明,浅层次生气藏与稠油油藏为伴生关系,且浅层次生气主要来源于稠油油藏的生物降解及油溶释放气;浅层次生气藏与稠油油藏在空间分布上具有明显的规律性,主要表现为次生气藏下方或下倾方向均发育稠油油藏、稠油油藏上方或上倾方向不一定发育次生气藏以及常规油藏上方或上倾方向未发育次生气藏。浅层次生气藏和稠油油藏共同构成一个相对独立的油气生、运、聚系统。

Shallow secondary gas reservoir and heavy oil reservoir mostly distribute in the periphery of source sub-sag,uplift belt and central uplift belt of in Jiyang depression. Based on the study of geology and geochemistry study in Jiyang depression,the relationship between the shallow gas reservoir and heavy oil reservoir were discussed through gas sources and genesis,thickening mechanism of heavy oil,dynamic balance between natural gas migration and accumulation and distribution pattern of shallow secondary gas reservoir and heavy oil reservoir. The results show that the shallow secondary gas reservoir is associated with the heavy oil reservoir,and the petroleum biodegradation and dissolved gas in the heavy oil reservoir provide its gas source. There are three evident distribution patterns:1Heavy oil reservoirs often develop below or along the downdip direction of shallow secondary gas reservoirs;2Shallow secondary gas reservoirs may not exist above or along the updip direction of heavy oil reservoirs;3No shallow secondary gas reservoirs exist above or along the updip direction of conventional oil reservoirs. The shallow gas reservoir and heavy oil reservoir formed a relatively independent system of hydrocarbon generation,migration and accumulation.