鄂尔多斯盆地西缘上古生界泥岩饱和烃Pr/Ph值特征及其地质应用

Pr/Ph Value of Saturated Hydrocarbon from the Upper Paleozoic Mudstone in Western Ordos Basin and Its Applications

通过对鄂尔多斯盆地西缘上古生界泥岩有机母质类型、有机母质热演化程度、有机质沉积环境等方面与泥岩饱和烃Pr/Ph值之间关系的分析,首次认识到西缘上古生界泥岩饱和烃姥鲛烷与植烷的比值(Pr/Ph值)小于1.0,并且主要受沉积环境水体咸度的影响,与有机母质类型、有机母质热演化程度的关系不明显。应用泥岩、煤岩饱和烃Pr/Ph值特征对盆地西缘上古生界凝析油的来源进行判识,指出上古生界凝析油主要来源于煤系地层,进而认为煤系地层在上古生界天然气成藏中起着决定性的作用。

Based on the relationship between the Pr/Ph values of mudstone saturated hydrocarbons and the types/maturity/depositional environment of organic matters in the Upper Paleozoic mudstone from the western Ordos basin,it is demonstrated that the Pr/Ph values which are lower than 1.0 are affected by the salinity of the depositional water medium and have no obvious correlation with the types and maturity of the organic matter.According to the Pr/Ph values of the saturated hydrocarbons in the mudstone and coal,it is concluded that the upper Paleozoic condensate oil in the western Ordos basin is originated from coal measures which has great significance on the upper Paleozoic gas accumulation.