金湖凹陷西斜坡油气运移分子地球化学研究

应用非烃技术、多馏分绝对定量技术,在分析苏北金湖凹陷原油、烃源岩地球化学特征、油源对比的基础上,重点对吡咯类含氮化合物在岩-油、油-油运移中的分馏效应进行了研究,并对骨架相似的另两类杂原子化合物-氧芴 (二苯并呋喃 )、硫芴 (二苯并噻吩 )的运移分馏效应作了初步探讨。结果表明,金湖凹陷西斜坡原油中吡咯类化合物具有较好的运移分馏效应,油气主体运移方向为东北至西南,相邻的三河次凹为其主要的油源区;杂原子化合物-氧芴、硫芴系列运移分馏效应不及吡咯类;绝对定量技术可弥补常规生物标志物在油气二次运移过程中异构体间分馏效应难以观察的不足,可作为继非烃技术后的另一评价油气运移过程的重要工具。

Oil Migration Study of the Western Slope, Jinhu Depression of Subei Basin, Eastern China

Oil migration effect of the western slope, Jinhu Depression of Subei Basin, Eastern China is observed on the base of detailed work of investigating genetic mechanism and source rock of the petroleum. The methods of the study adopted include non hydrocarbon and absolute quantitative analysis of biomarkers and the other kind of the compounds in different fractions by co injection of standard compounds. The main method is emphasized on studying the migration fractionation effect of pyrrolic nitrogen compounds in the oil. The other two kind compounds' migration fractionation effect is also observed, which are dibenzofuran and dibenzothiophene series with the similar molecular structure as the pyrrolic nitrogen compounds. The result indicates that the pyrrolic nitrogen compound in the oil has apparent migration fractionation effects, which infer the oil migration direction of the area is form northeast to southwest, and the Shanghe Sag is the main source cooker of the oil. The migration fractionation effects could also be observed in the other two kind compound series dibenzofuran and dibenzothiophene bearing oxygen and sulfur heteroatom respectively, which make the compounds having strong polarity too. However, their fractionation effects are not apparent as the nitrogenic compound. The migration fractionation effects of the three compounds increase according to the order of dibenzoghiophene, dibenzofuran and nitrogen compounds, which infer the polarity of the three kind compounds increasing according to the order. It is probably the hetroatoms in the compounds determining the chemical characteristics of the compounds. The results also indicate that the absolute quantitative analysis is very useful in study petroleum migration, the migration fractionation effect could be observed from the abundance variation of some high molecular compounds, especially the heterocyclic compounds such as NSO' compounds metioned above.