Geochemical Characteristics and Origins of Typical Marine and Terrestrial Oils in the Northeastern Sichuan Basin
详细信息
- 责任者：Zhu Yangming (Department of Earth Sciences ; Zhejiang University ; Hangzhou 310027 ; China) ; Hu Wei
- 刊名：Acta Petrolei Sinica
- 出版年：2013
- 卷期：34(2)
- 关键词：原油 ; crude oil ; 油—源对比 ; oil-source rock correlation ; 四川盆地 ; Sichuan Basin
- 页码：p.255-262
- 图表：illus., 1 table, 22 refs.
- 分类号：1003
- issnNo：ISSN0253-2697
- isbnNo：CN11-2128/TE
摘要
Saturated and aromatic fractions of typical marine and terrestrial oils and seepages collected from exploratory wells and outcrop in the northeastern Sichuan Basin,respectively,were characterized in molecular geochemistry using GC/MS and GC/MS/MS and their origins were also discussed in combination with analytical data of source rocks.The results indicated that oils from the Middle Jurassic Qianfoya Formation in Well Xinqingxi-1 in Puguang structural belt and Well Yuanba-9 in Yuanba structural belt show a pristane predominance over phytane(Pr/Ph>1.5),low amount of tricyclic terpanes with ETR values below 1.2 and abundant fluorene series in aromatic hydrocarbons.Based on the correlation of carbon isotopes between oils and kerogens from related source rocks,the oils were validated to be derived from lacustrine source rocks of the Qianfoya Formation.However,these two oils could have different organic sources and depositional settings due to a significant difference in diahopane abundance.The Permian oil in Well Chuanyue-84 of Puguang structural belt shows a relatively low Pr/Ph ratio(0.82),abundant tricyclic terpanes and detectable C26 norcholestane.Carbon isotopes indicated a genetic correlation between the oil and marine source rocks of the Upper Permian Longtan Formation.The seepages from the Feixianguan and Changxing formations in Erlangmiao,Jiangyou area are characterized by dominant C29 sterane over C27 and C28 homologues,a high 24-isopropyl-/24-n-propyl-cholestane ratio(1.1),predominant 3β-and 2α-methylsteranes in methylated steranes,a low 24-/(24-+27-)norcholestane ratio(below 0.2) and the absence of triaromatic dinosteroids.These age-related biomarkers,in conjunction with the isotopic depletion for whole oils(-34.1‰ to-34.6‰),suggested that the seepages could originate from Sinian-Cambrian source rocks.