控制内蒙古二连盆地达尔其油田石油富集度的关键因素——不同油源原油的混合作用

在对3套烃源岩的质量和成熟度描述基础上,通过对原油物理性质、族组成和生物标志化合物参数的研究,在达尔其油田内划分出成熟度有明显差异的低熟油和成熟油。油源对比结果认为它们分别由都红木组一段低熟烃源岩和阿尔善组二段成熟烃源岩所生。推测成熟度参数介于低熟和成熟之间的原油为混源油。通过原油混合试验和油砂连续抽提试验证实了混源油的推测。通过油藏剖面中不同性质油层的分布特征研究,结合断层发育史与油气运移关系分析认为不同油源原油的混合是控制该油田石油富集度较高的关键因素。此外,还分析了控制混源的断层组合特征。

The Mixing of Oils from Different Source Rocks:A Key Factor of Oil Enrichment of Daerqi Oilfield in Erlian Basin, Inner Mongolia

Based on physical features, gross compositions and biomarker compounds, the crude oils in Daerqi oilfield are classified into two types with distinct maturations: low mature and mature oil. Oil-source correlation shows that the oils are derived from low mature source rock of the Duhongmu Formation and mature source rock of the Aershan Formation respectively. The oil maturation index between low and mature may be the mixture of two source rocks. The inference can be proved by the artificial oil mixing test and oil-bearing sand serial extraction. By analyzing the characteristics of oil distribution and the relationship between hydrocarbon migration and fault developing history, it is concluded that the mixing of oils derived from different source rocks is a key control factor in oil enrichment.