Study of unresolved complex mixtures in crude oil

Unresolved complex mixtures(UCM) usually refer to hydrocarbons existing in crude oils(especially biodegraded oils).They are difficult to distinguish with normal GC,and include over 250 000 types of compounds.The effective discrimination of UCM may provide new geochemical information for crude oil genesis analysis,production,refinement as well as residual oil pollution evaluation and treatment.Rather than the definition of UCM,it is also discussed in this paper the experiment technology progress and the compound features of UCM as well as the applications in petroleum exploration,deve-lopment and environment protection.The problems in UCM studies and the future targets are also pointed out.