塔里木盆地阿克苏地区下寒武统储层沥青地球化学特征及来源分析

Geochemical Characteristics and Origin Analysis of Bitumen in Lower Cambrian in Aksu Area,Tarim Basin

阿克苏地区寒武系玉尔吐斯组、奥陶系萨尔干组和印干组发育有良好的烃源岩,石灰窑剖面寒武系吾松格尔组和沙依里克组发育储层沥青。阿克苏地区构造的复杂性可能对油气运移产生影响,不能确定沥青和两套烃源岩的亲缘关系。通过对正构烷烃、类异戊二烯烃和萜烷、甾烷、芳烃等生物标志化合物参数对比分析显示,沥青和玉尔吐斯组烃源岩在有机质来源、沉积环境和热演化程度等方面具很好的关联性,推断寒武系储层沥青为玉尔吐斯组烃源岩。对比发现,C27、C28和C29规则甾烷的峰型特征在阿克苏地区寒武系和奥陶系烃源岩对比上并不适用。通过对阿克苏地区寒武系储层沥青来源研究,可对台盆区下古生界油源问题的研究提供参考和启示。

There are good source rocks in the Cambrian Yuertus Formation and Ordovician Sargan Formation and Yingan Formation,and reservoir bitumen in Cambrian Wusongger Formation and Shayilike Formation in Shihuiyao Section.Considering the possible influence of the complex structural on hydrocarbon migration in Aksu area,the relationship between bitumen and two sets of source rocks can not be determined,so the geochemical characteristics of them are tested and analyzed.By comparing and analyzing the parameters of biomarker compounds,it is shown that there is a good correlation between bitumen and source rocks of Yuertus Formation.It can be concluded that Cambrian reservoir bitumen is derived from the source rocks of Yuertus Formation.It is also found through comparison that the peak type characteristics of C27,C28,and C29 regular steranes are not applicable for the comparison of Cambrian and Ordovician source rocks in Aksu area.We hope that this study can provide some references and inspirations for the study of Lower Paleozoic oilsource in Tarim Basin.