松辽盆地岩性油藏形成背景与成藏条件分析

Origin background and reservoir forming condition of lithologic oil pools in Songliao Basin

松辽盆地岩性油藏非均质性强 ,以薄互层为主的储层变化快 ,成藏条件较为复杂 ,隐蔽性强 ,不易发现。因此 ,应用板块构造、层序地层学以及成藏系统等方面的新理论、新方法 ,深入开展构造、沉积及油气成藏条件等方面的研究 ,对岩性油藏的形成条件与分布规律有了新认识 :提出了长期稳定的构造沉降是形成大面积岩性油藏的基础 ;湖平面频繁波动、湖岸线进退交替变化 ,导致纵向上砂泥岩交互沉积 ,形成了多套含油组合 ,在三角洲前缘的砂泥岩交互沉积带形成了多种类型的岩性圈闭 ;下、中、上 3个成藏系统岩性油藏的成藏条件与控制因素又各不相同。在这些认识指导下进行了有利区预测 ,指出了勘探方向 ,对于松辽盆地以及类似盆地的油气勘探具有重要指导意义。

Heterogeneity of lithologic oil pools is high in Songliao Basin,which reservoir is dominated by thin interbed and changes quickly,its forming condition is more complex,concealment is strong and is hard to discover.Therefore,using new theory,new method of plate tectonics,sequence stratigraphy and reservoir-forming system,etc.to implement tectonics,sedimentation and hydrocarbon-forming condition study and achieving a new understanding to origin condition and distribution rule of the lithologic oil pools.The study shows that long time and stable tectonic subsidence is the basis of forming a large-scale lithologic oil pool. Level of lake waves frequently and alternately changes the lake shoreline,resulted in sand-shale interactive deposits in vertical,forming multi sets of oil-bearing assemblages and all kinds of type of lithologic traps formed in sand-shale interactive sedimentation zone of delta front.The reservoir forming condition and controlling factor of the upper,middle and the lower three reservoirs forming system is defferent.Under this guideness a favourable prediction is made.It points out exploration direction and it has an important guiding sence for hydrocarbon exploration in Songliao Basin and in like basins.