原油极性分离法及其对解释原油碳同位素特征的作用

METHOD OF SEPARATING OIL IN ORDER OF POLARITY AND ITS CONTRIBUTION TO COMPREHEND THE CHARACTERISTICS OF STABLE CARBON ISOTOPE OF CRUDE OIL

为了研究原油有机分子极性与其碳同位素的关系,建立了一种按极性分离石油的方法,并用这种方法分离了胜利油田的原油样品和做了碳同位素分析,随后又用族组分分离方法分离了相同的油样并做了碳同位素分析。通过对比,发现用这2种方法分离出的原油组分在总体上具有一定的相似性,即组分极性都有由小向大变化的趋势,但在细节上又有一定的区别,族组分分离法将原油分为4个组分,而极性分离法将原油分为5个组分,并且各组分之间也不是简单的对应关系;同时发现芳香烃和非烃的极性跨度相对较大。在此基础上,分析了原油中的有机分子极性与其碳同位素值的关系,得出了随极性增加1δ3C值增加的结论,并将此结论用于原油是单源还是多源解释上,指出了原油同位素出现逆转现象的原因,另外据此还建立了简单的数学模型,由已知的组分含量及1δ3C值求出了混合原油中各生油层所占的比例。

A method of separating oil by polarity has been constructed for exploring the relationship between the polarity of organic molecules and the δ^13C of them in crude oil. We divide a sample of oil from Shengli oil field into five parts by this method, and measure the δ^13C of each part. Similarly, we divide another sample of the same oil into four parts by the old method, and measure the δ^13C of each part. By contrasting these two methods in their steps of experiments and separating results, we conclude that： （1） they are similar that the polarity increases from the first component to the last component in both methods; yet （2） they are distinct in details： in the polar method oil sample is separated into five parts, one more than that in the old method and more meticulous; （3） by comparing each part of them, we point that aromatic hydrocarbon and non-hydrocarbon both have a large span in polarity; and （4） we show that the polarity of organic molecules in oil increases as their δ^13C value rises in isotopic theory and the analysis of our experiment results. In the end, we construct a mathematical model on this conclusion to explain the reverse order in oil.