Genetic types of the oils were classified in this paper, and their migration and accumulation were discussed. Based on artificial oil mixing experiments, it is found that some biomarker compositions of oils show regularities along with mixing ratios of oils. Thus, these representative biomarkers may be criteria for determining origin of mixed oils. According to the criteria, oils in the area were divided into four types. Migration and accumulation of the four type oils were further discussed, combined with geological backgrounds.