鄂尔多斯盆地西南缘奥陶系泥页岩与碳酸盐岩生物标志物特征对比  

Contrasting Biomarker Characteristics of Ordovician Mud Shale and Carbonate Rocks in South-western Margin of Ordos Basin

作　　者：王万春[1] 王晓锋[1] 郑建京[1] 王作栋[1] 

机构地区：[1]甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室,兰州730000

出　　处：《沉积学报》2016年第2期404-414,共11页Acta Sedimentologica Sinica

基　　金：国家重点基础研究发展规划计划(973计划)项目(2012CB214801);国家科技重大专项(2011ZX05005-001);甘肃省重点实验室专项(1309RTSA041)~~

摘　　要：通过采集鄂尔多斯盆地西南缘4个剖面奥陶系马家沟群碳酸盐岩和平凉组泥页岩样品,对其中可溶有机质饱和烃与芳烃组分进行GC-MS分析,对比研究了马家沟群碳酸盐岩和平凉组泥页岩生物标志化合物特征。结果表明,马家沟群与平凉组正构烷烃分布形式及峰型特征、生物标志化合物参数Pr/Ph、伽马蜡烷/C30-αβ藿烷、C20-29三环萜烷/(C20-29三环萜烷+C27-35藿烷),以及甲基菲指数(MPI)均存在明显差异,这些差异反映了其沉积环境与成熟度的不同,对于马家沟群与平凉组来源油的识别具有参考价值。马家沟群正构烷烃分布形式与甾/藿比值以及C28/C29ααα20R甾烷比值之间的对应关系,反映了母质输入的细微差别。Ts/(Ts+Tm)与伽马蜡烷/C30-αβ藿烷比值之间的关系,C29甾烷αββ/(αββ+ααα)比值变化与重排藿烷与重排甾烷丰度的关系,反映上述成熟度参数明显受沉积环境影响。Carbonate rocks of the Majiagou Formation and mud shale rocks of the Pingliang Formation of the Ordovician system were sampled from 4 sections in the south-western margin of the Ordos Basin. GC-MS analyses were made on the saturated and aromatic hydrocarbons of the dissolved organic matter extracted from the rock samples. Contrasting studies were made on the biomarker characteristics of carbonate of the Majiagou and mud shale of the Pingliang formations. The results show that there exist obvious differences in the n-alkane distribution types,peak patterns,biomarker ratios of Pr / Ph,gamacerane / C30-αβ-hopane,C20-29 tricyclic terpanes /（ C20-29 tricyclic terpanes ＋ C27-35hopanes）,and methylphenanthrene index（ MPI） between carbonate of the Majiagou and mud shale of the Pingliang formations. These differences are the results of different depositional environments and thermal maturities of the Majiagou and Pingliang formations and are significant for the discriminating of oils derived from the Majiagou and the Pingliang formations. The corresponding relations among the n-alkane distribution types,the sterane / hopane ratio and the C28/C29ααα20R ratio of steranes in the Majiagou Formation reflect subtle differences in organic matter sources. Correlations between Ts /（ Ts ＋ Tm） and gamacerane / C30-αβ-hopane ratios,and between C29-sterane αββ/（αββ ＋ ααα）ratio and abundances of rearranged hopanes and steranes suggest obvious influence of depositional environment on these maturity parameters.

关 键 词：鄂尔多斯盆地 马家沟群 平凉组 生物标志化合物 

分 类 号：P593[天文地球—地球化学]