东濮凹陷盐湖相原油氮/氧化合物分布特征及其应用

东濮凹陷盐湖相原油中杂原子化合物研究薄弱。采用高分辨率质谱技术、结合色谱-质谱,对东濮凹陷盐湖相、淡水湖相原油、烃源岩中的含氮、氧化合物进行了检测。结果表明,原油中含有丰富的氮、氧化合物, N₁、O₁和O₂占绝对优势;随成熟度增加,N₁和O₁类化合物相对丰度增加、O₂类化合物相对丰度降低、氮/氧化合物的缩合度增加、烷基侧链碳数范围降低,提出了多项氮、氧化合物的成熟度辅助识别指标,建立了DBE₁₅/DBE₉-N₁和DBE₁₅⁺/DBE₁₄^--N₁与折算镜质体反射率之间的定量关系式。通过对氮、氧化合物的油-油、油-岩对比,认为东濮凹陷盐湖相原油主要来自成熟烃源岩。基于高分辨率质谱的氮、氧化合物具有重要的成熟度评价、油源对比、油气运移示踪的应用前景。

Distribution and Application of Nitrogen and Oxygen Containing Compounds in the Saline Lacustrine Oils from the Dongpu Sag

Heteroatomic compounds in saline lacustrine in the Dongpu Sag are weakly documented. ESI FT-ICR MS combined with GC/MS were utilized to reveal oxygen and nitrogen compounds in the saline lacustrine oils and source rocks in the sag. Abundant NO compounds were detected and dominated by N₁, O₁ and O₂ class species. It was observed that the relative abundance of the N₁ and O₁ species increased with increasing maturity, while the contents of O₂ species decreased with increasing maturity. It was also observed that there is an apparent increase in the condensation degree and a decrease in the carbon number of the N₁, O₁ and O₂ species with increasing of maturity. Several indices including DB₁₅⁺/DBE₁₄^--N₁ having a good relationship with calculated vitrinite reflection (R_c). Oil-oil and oil-source rock correlations based on-ESI FT-ICR MS showed that, the majority of the saline lacustrine oils in the northern Dongpu Depression was sourced from the relatively mature source rocks. It was proved that nitrogen and oxygen containing compounds have a good application prospect in maturity evaluation, source rock and hydrocarbon migration tracing.