鄂尔多斯盆地宜川地区上古生界烃源岩评价

Evaluation for hydrocarbon source rocks in YiChuan of Ordos basin ancient life world

依据氢指数(HI)、降解率(PC/TOC)等两个方面的地球化学指标,按照煤系地层烃源岩有机质类型划分标准,对研究区的山西-太原组烃源层的有机质类型作剖析,进行上古生界烃源岩系统评价。研究认为,本溪组烃源岩主要是泥岩,有机质丰度平均2.51%,泥岩干酪根母质类型主体属腐殖型干酪根,即Ⅲ型干酪根;太原组暗色泥岩有机质丰度平均2.26%,煤层比较发育,有机质丰度平均81.66%;山西组的泥岩比较发育,泥岩有机质丰度平均2.26%,煤层有机质丰度平均72.66%。本区上古生界干酪根显微组分都以镜质组为主,显示干酪根母质为腐殖型,即Ⅲ型干酪根,热成熟度演化较高,Ro都大于2.5%,Tmax为490℃以上,表明泥岩已达到过成熟阶段,本区暗色泥岩及煤层属中等—好气源岩,此次烃源岩的认识对该区下一步的勘探提供重要的依据。

This paper mainly based on hydrogen index（HI）,degradation rate（PC /TOC） in the two aspects of geochemical index,according to the coal formation hydrocarbon source rocks organic type division standard,in the study area of shanxi-the taiyuan formation of organic type of hydrocarbon source for analysis,born in ancient world hydrocarbon source rocks evaluation system.Research thinks,benxi group of hydrocarbon source rocks is mainly mudstone,on average,2.51% organic matter abundance,mudstone kerogen organic types of corruption subject colonization kerogen type,namely Ⅲ kerogen type;Taiyuan group dark mudstone organic matter abundance an average 2.26%,coal seam comparison development,organic matter abundance average 81.66%;Shaanxi group of mudstone more development,mudstone organic matter abundance an average 2.26%,coal organic matter abundance an average of 72.66%.Born in the ancient world kerogen microscopic components are mirror mass group is given priority to,show kerogen cane for budding type corrosion,namely Ⅲ kerogen type,hot maturity evolution is higher,Ro than 2.5% and Tmax for 490℃ above,show that has been achieved in mature stage sandstone,the dark mudstone and coal seam is medium-spirit.