松辽盆地石炭系-二叠系油气勘探前景

摘要

Based on analysis of the regional geological background, northeastern China is in the tectonic background of active continental margin, and formed pan-basin of Carboniferous-Permian.Formation and evolution of Songliao Basin was on the residual basins of Carboniferous-Permian with the area of 7.2×104km2.The geochemical analysis showed that Permian strata mainly composed of extremely low class metamorphic rocks, and the mudstone of Permian had the high organic matter maturity and abundance and the low residual hydrocarbon generation potential.Permian mudstone of basin eastern with the thickness over 1000m is in the over-mature stage possessed the hydrocarbon generation potential up to now, and the organic maturity of which is less than that of northern basin and western basin.Since the sedimentary of Mesozoic formation, Permian mudstone of eastern basin with larger increase amplitude of organic maturity has happened the secondary hydrocarbon generation of the great hydrocarbon generating quantity, which can be preserved effectively and form primary and secondary reservoir.The mudstone had better exploration prospect.%通过区域地质背景分析,认为东北地区处于活动大陆边缘构造背景下,形成了石炭纪-二叠纪泛盆地,松辽盆地是在残留的石炭系-二叠系盆地之上形成和演化的,石炭系-二叠系分布面积达7.2×104km2.地球化学分析表明,二叠系以极低变质岩为主,泥岩的有机质成熟度和丰度较高,剩余生烃潜力普遍较低.盆地东部地区的二叠系泥岩厚度超过1000m,而成熟度低于北部和西部地区,处于过成熟阶段,至今仍具备生烃能力.上覆中生代地层沉积后,东部地区的二叠系泥岩有机质成熟度增幅较大,发生了二次生烃,生烃量巨大并得到有效保存,形成原生和次生油气藏,具有较好的勘探前景.