Hydrocarbon potential of Upper Paleozoic in Yanbian area, Jilin Province

The research extent of the Upper Paleozoic hydrocarbon resources is low in Yanbian area of Jilin Province. Through numerous trenching samplings and geochemical tests, combining with gravity-magnetic and seismic data interpretations, the distribution of the Upper Paleozoic and the organic abundance, type and maturity of dark mudstones in the study area were studied. In Yanbian area, the Upper Paleozoic is wide distributed and is rich in dark mudstone with high organic carbon content. As a whole, the dark mudstones are medium or good source rocks, which mainly produce Ⅱ-Ⅲ kerogen but with high organic maturity. In the southwestern and northeastern parts of the study area, organic matters are over matured, and the R_o value is over 4.0%, indicating for poor hydrocarbon potential. In Tianqiaoling-Hunchun area which locate in the center of the study area, the R_o value ranges from 2.22% to 3.48%, and organic matters are during the high mature-dry gas effective gene-ration stages. The Upper Paleozoic dark mudstones in the basement of the Huichun Basin have good hydrocarbon exploration potential.