Test results of different types of crude oils show th at pyrrolic compounds such as carbazole,benzocarbazole and dibenzocarbazole are found,and the first two types are predominent.

• 不同类型原油的实验结果表明：原油中存在咔唑、苯并咔唑及二苯并咔唑3类吡咯类化合物，且以前两类为主。