塔东地区奥陶系——寒武系烃源岩评价

EVALUATIONS OF ORDOVICIAN AND CAMBRIAN SOURCE ROCKS IN EAST TARIM

塔里木盆地塔东地区是大庆油田油气勘探的重要接替领域,其有效烃源岩、生烃潜力评价直接影响该区的整体勘探决策。在岩石热解分析、有机质镜下检测等实验分析基础上,对奥陶系、寒武系烃源岩的有机碳含量、有机质类型及有机质成熟度等进行了分析。结果表明:去污染分析后的奥陶统却尔却克组烃源岩有机碳含量较低;有机质类型既有腐殖型也有腐泥型;上奥陶统烃源岩为非-差烃源岩,中-下奥陶统的黑土凹组、寒武系为好烃源岩,有机质类型以海相腐泥型为主,烃源岩处于过成熟阶段;泥岩、泥质灰岩有机质含量较高,为有效烃源岩,碳酸盐岩的有机质含量较低,多为非烃源岩。

East Tarim is the important replacing region of the petroleum exploration of Daqing Oilfield, the evalua- tions of the effective hydrocarbon source rocks and hydrocarbon generating potentials directly influence the decision making of the whole exploration in this area. On the bases of the experimental analyses of the rock pyrolysis, the microscope observation of the organic matters and so forth, the organic carbon contents, types, maturity and so on for Ordovieian and Cambrian source rocks are figured out. The results show that the content in Ordovician Queerqueke Formation is rather lower after the analysis of the decontamination ; there are both humic and sapropelic types of the organic matters ; Upper Ordovician source rocks belong to non-poor hydrocarbon source rocks, while the ones in Heituao Formation and Cambrian system in Middle-Lower Ordovieian series are pretty better, the organic matter type is mainly marine sapropelic one, the source rocks are in the stage of over maturity ; the contents of the organic matters in the mudstone and argillaceous limestone are greatly higher, thus the effective source rocks are generated, whereas the contents of the organic matters in the carbonate rocks are rather lower, so the rocks develop into nonhy（]ro（~al＇[）Ol] S（）LII＇CC OIl（qS.