低熟油、烃源岩中含氮化合物分布规律及其地球化学意义

Characteristics of pyrrolic nitrogen compounds and their geochemical significance in oils and rocks of Bamianhe oilfield, eastern China

对八面河地区原油、油砂以及不同成熟度和岩性有异的烃源岩中吡咯类化合物的分布特征及其潜在的地球化学意义进行了探讨。结果表明,随着成熟度的增加,八面河地区烃源岩中吡咯类化合物中屏蔽化程度高的异构体比屏蔽化程度低的异构体富集,咔唑及苯并咔唑系列中低相对分子质量的同系物比高相对分子质量的同系物富集,苯并犤a犦咔唑比苯并犤c犦咔唑富集。八面河地区原油中吡咯类化合物有较为明显的运移分馏效应,观察到高、低相对分子质量的同系物间的运移分馏效应比不同类型异构体间的分馏效应更为显著,而前者受成熟度的影响可能相对小于后者;发现吡咯类化合物的油气运移分馏效应不仅体现于不同氮官能团屏蔽、半屏蔽和暴露三类异构体间,同样体现于同一类型的同分异构体之间,指示此类化合物有较强的活性。吡咯类化合物与烃类化合物一样具有多方面潜在的地球化学意义。

A discussion of relative distribution and geochemical significance of pyrrolic nitrogen compounds in crude oils, oil sands and potential source rock bitumens with wide range of maturity and lithology from Bamianhe oilfield, eastern China are executed. Results show that with increasing of maturity, the extracts of the source rocks show a tendency to enrich nitrogen shield isomers relative to nitrogen exposed isomers; low relative molecular mass of the compounds of carbazoles and benzocarbazoles series relative to high molecular mass ones; and benzocarbazole relative to benzocarbazole. Significant oil migration effects of nitrogen compounds in the oils are observed. It seems migration effect among pseudo homolog of carbazoles and benzocarbazoles is more apparent than that among nitrogen marked, partially marked and exposed isomers. It is inferred that the impact of maturity on the former is much more than that of the later. Results also indicate that migration effect of the compounds could be observed not only between different type isomers but also between the same type isomers suggesting strong polarity and its difference among the compounds.