塔里木盆地原油中性含氮化合物的运移分馏作用

Migrational Fractionation of Neutral Nitrogen Compounds of Crude Oil in Tarim Basin

塔里木盆地原油中性含氮化合物的绝对浓度和相对比值,揭示出原油中性含氮化合物垂向上从奥陶系油藏到TI油藏存在着明显的运移分馏效应。表现为绝对浓度由大变小,屏蔽型化合物相对富集而部分屏蔽型化合物和裸露型化合物含量相对贫瘠,苯并[a]咔唑/苯并[c]咔唑的比值则由高变低。LN14井油藏原油中性含氮化合物的分布特征,不仅反映了原油中性含氮化合物在单井中的运移分馏效应十分明显,而且当来源于寒武系-奥陶系海相烃源岩的原油中混合石炭系烃源岩生成的原油时,原油中性含氮化合物的分布模式将发生变化。

The absolute concentration and relative proportionality of neutral nitrogen compounds of crude oil in Tarim Basin reveal that obvious migrational fractionation is caused vertically from Ordovician reservoirs to TI reservoirs, of which the obsolute concentration goes low from high, the content of nitrogen-shielded compounds of dimethylcarbazoles is relatively abundant,but the contents of nitrogen-partially-shielded compounds and nitrogen-exposed compounds of dimethylcarbazoles are lower. The proportionality of benzo[a] carbazole to benzo[c] carbazole becomes low from high. The distributional characteristics of the neutral nitrogen compounds in crude oil in the reservoirs of Lunnan Well 14 not only reflect obvious migrational fractionation of the neutral nitrogen compounds in single well, but also reflects that when the oil originated from Cambrian-Ordovician marine source rocks is mixed with that from carboniferous source rocks, the distributional patterns of dimethylcarbazoles in oil are changed.