西乌珠穆沁旗地区上二叠统北大山组油气地质特征

The Reservoir Geological Characteristics of the Upper Permian Beidashan Formation in the Western Ujimqin Banner

通过野外实地剖面测量,将西乌珠穆沁旗地区上二叠统北大山组(P_3b)划分为4种沉积相带,从下到上依次发育前缘陡坡、盆地-陡坡过渡带、裂陷盆地、前缘陡坡、礁滩,具有良好的生储盖组合关系。在上述研究基础上,结合有机地球化学以及岩石学等方法,对P_3b烃源岩有机质丰度、有机质类型、有机质成熟度和泥页岩矿物组成进行评价。结果表明,西乌珠穆沁旗地区P_3b烃源岩属于较好烃源岩,泥、页岩硅质含量高,排烃能力强,利于油气的富集和成藏,可作为好的油气勘探选区。

Based on field profile detection,the upper Permian Beidashan Formation(P_3b)is divided into 4sedimentary facies bands,from the bottom up,there develop a front steep slope,basin-slope transition band,rift basin,frontier steep slope and reef beach,where there exists a good relationship of source-reservoir-caprock assemblage.Based on the study mentioned above,and combined with the methods of geochemistry and petrology,the characteristics of the source rock abundance,type of organic matter,maturity of organic matter and the composites of mud shale of the P_3 bsource rock are evaluated.Results indicate that the P_3 b source rock in the Western Ujimqin Banner belongs to a better source rock with high silicon content of mud and shale rocks,its hydrocarbon expulsion capacity is high,it is beneficial for hydrocarbon accumulation and formation,it can be a candidate area for oil and exploration.