根据烃源岩地球化学、岩石学、沉积学、构造沉降及古气候等特征,对辽东湾地区古近系3套湖相烃源岩发育的主控因素进行综合分析。结果表明:3套烃源岩均形成于温暖湿润的还原环境,生产力高;沙三段烃源岩形成于快速沉降的深水窄盆环境,水体根据温度和弱盐度分层,且具最高生产力;沙一段烃源岩形成于沉降速率低的浅水广盆环境,水体根据高盐度分层,且有机质生源高等植物贡献小;东下段烃源岩形成于快速沉降的深水广盆环境,水体根据温度和弱盐度分层;同层内烃源岩的差异受沉积相控制;沙三段烃源岩生烃潜力最好,沙一段次之,再次为东下段。
According to the source rocks characteristics in respect to geochemistry,petrology,sedimentology,tectonic subsidence and ancient climate,the main controlling factors of three sets of Paleogene lacustrine source rocks in Liaodong Bay area were comprehensively analyzed.The results show that the three sets of hydrocarbon source rocks were all with high productivity and formed in warm,moist and anoxic condition.The source rocks in member 3 of Shahejie formation were formed in the environment of deep-water and narrow lacustrine basin with high subsidence rate and the highest productivity.The stratified water column relied on temperature and low salinity.The source rocks in member 1of Shahejie formation were formed in the environment of shallow-water and wide lacustrine basin with low subsidence rate.The stratified water column relied on high salinity.The organic matter was few higher plants.The source rocks in lower Dongying formation were formed in the environment of deep-water and wide lacustrine basin with high subsidence rate.The stratified water column relied on temperature and low salinity.The heterogeneity in the same set of source rocks was controlled by sedimentary facies.The hydrocarbon generating potentiality in member 3 of Shahejie formation is the best,member 1 of Shahejie formation is second and the lower Dongying formation is third.