期刊名称：Journal of Applied Sciences and Environmental Management
印刷版ISSN：1119-8362
出版年度：2018
卷号：22
期号：3
页码：356-361
出版社：Department of Pure & Industrial Chemistry, University of Port Harcourt
摘要：Rock samples from the offshore Niger Delta basin, Nigeria were characterized by the predominance of C 26 20R + C 27 20S TAS peak using GC-MS. Among the compounds identified in m/z 245 mass chromatograms, C 21 methyltriaromatic steroids, C 22 methyltriaromatic steroids and C 27 , 4-methyltriaromatic steroid + C 29 , 4-methyl-, 24-ethyltriaromatic steroid were the dominant compounds in the rock samples from MJI oilfield while the rock samples from MJO oilfield were characterized by higher abundance of aromatic dinosteroids. All the compounds identified in the m/z 245 mass chromatograms of rock extracts from OKN were relatively low compared to the rock samples from MJI and MJO oilfields. The source rocks were found to be formed from mixed origin (terrestrial and marine) but with significant contribution of dinoflagellates to the organic matter and deposited in freshwater-brackish/saline lacustrine environment. The source rocks were found to have immature to early oil window maturity status based on the distributions and abundance of triaromatic steroids in the source rocks and this was further supported by well-established maturity parameters based on the saturate and aromatic biomarkers. This study showed that the abundance and distribution of triaromatic steroids and triaromatic dinosteroids can be used to assess the origin, depositional environments and thermal maturity of source rocks in the Niger Delta Basin.
其他摘要：Rock samples from the offshore Niger Delta basin, Nigeria were characterized by the predominance of C 26 20R + C 27 20S TAS peak using GC-MS. Among the compounds identified in m/z 245 mass chromatograms, C 21 methyltriaromatic steroids, C 22 methyltriaromatic steroids and C 27 , 4-methyltriaromatic steroid + C 29 , 4-methyl-, 24-ethyltriaromatic steroid were the dominant compounds in the rock samples from MJI oilfield while the rock samples from MJO oilfield were characterized by higher abundance of aromatic dinosteroids. All the compounds identified in the m/z 245 mass chromatograms of rock extracts from OKN were relatively low compared to the rock samples from MJI and MJO oilfields. The source rocks were found to be formed from mixed origin (terrestrial and marine) but with significant contribution of dinoflagellates to the organic matter and deposited in freshwater-brackish/saline lacustrine environment. The source rocks were found to have immature to early oil window maturity status based on the distributions and abundance of triaromatic steroids in the source rocks and this was further supported by well-established maturity parameters based on the saturate and aromatic biomarkers. This study showed that the abundance and distribution of triaromatic steroids and triaromatic dinosteroids can be used to assess the origin, depositional environments and thermal maturity of source rocks in the Niger Delta Basin.
