摘要
Partition coefficient difference of benzocarba-zole isomers between oil, water and mineral phase makes them a useful indicator to quantify petroleum migration distance. Because of their nitrogen-heteroatom and annelated aromatic cycles they are generally regarded as being more resistant and the effects of biodegradation on their concentrations and distributions have not previously been investigated. Reservoir extracts from three wells located in the Leng43 block of the Liaohe Basin were analyzed to investigate their occurrence and the effect of biodegradation. Both hydrocarbon biomarkers and benzocarbazole isomers show systematical changes with the increase extent of biodegradation in study columns. Carbazole compounds may be biodegraded in a similar way to that observed in aliphatic and aromatic hydrocarbons. The distance from oil water contact is a primary control factor for biodegradation. The concentrations of benzocarbazole isomers show a slight increase in the upper part of the columns then a
Partition coefficient difference of benzocarba-zole isomers between oil, water and mineral phase makes them a useful indicator to quantify petroleum migration distance. Because of their nitrogen-heteroatom and annelated aromatic cycles they are generally regarded as being more resistant and the effects of biodegradation on their concentrations and distributions have not previously been investigated. Reservoir extracts from three wells located in the Leng43 block of the Liaohe Basin were analyzed to investigate their occurrence and the effect of biodegradation. Both hydrocarbon biomarkers and benzocarbazole isomers show systematical changes with the increase extent of biodegradation in study columns. Carbazole compounds may be biodegraded in a similar way to that observed in aliphatic and aromatic hydrocarbons. The distance from oil water contact is a primary control factor for biodegradation. The concentrations of benzocarbazole isomers show a slight increase in the upper part of the columns then a sharp decrease towards oil water contact (OWC). Among three isomers benzo[a]carbazole seems more susceptible to biodegradation than other two isomers and benzo[b]carbazole has higher ability to resist bacterial attack. Benzo[b]carba-zole/benzo- [a]carbazole ratios can sensitively indicate the degree of biodegradation and the benzocarbazole index (BC ratio) cannot be directly used as a migration indicator in biodegraded oils.
基金
This work was supportedby British Oversea Research Scholarship and University of Newcastle-upon-Tyne.
