A Discussion on Petroleum Migration in the Wunan Oilfield of Qaidam Basin Based on Nitrogen Compounds

Nitrogen compounds are a kind of non-hydrocarbon fraction,and could be used as effective tracers in oil migration and as parameters in evaluating the quantity of migrated oil.Using the nitrogen compounds in the crude oil composition and relative abundance of change,combined with hydrocarbon biomarker analysis of the characteristics of crude oil,the authors discuss on petroleum migration in the Wunan oilfield of Qaidam basin.The results indicate that the type of Wunan crude oil is more consistent from the same source.Significant oil-migration effects of nitrogen compounds in the oils are observed.With the strengthening of the role of migration,the concentration of nitrogen compounds is decreased.It seems that migration effect among pseudo-homolog of carbazoles and benzocarbazoles is more apparent than that among nitrogen marked,partially marked and exposed isomers.The results also show Wunan crude oil may be generated on its adjacent westside depression.The oils are likely to migrate from west to north and from northwest to southeast.