Genetic type and features of oil shale in the Minhe basin, Qinghai-Gansu Province, China

Based on the data of drilling cores and analysis test, it is discussed about the sedimentary environment, the characteristics of sequence stratigraphy, occurrence, industrial qualities and geochemistry of oil shale in Minhe basin. The oil shale was classified into three genetic types, which include the sapropelic type oil shale of deep-semis lacustrine facies in the first oil shale bed, the humosapropelic type of shallow lacustrine facies in the third oil shale bed, and the sapropelic-humic type of lacustrine bog in the fourth oil shale bed. The researches indicate that the first oil shale bed developed in deep-semis lacustrine distributes widely with large thickness. It is belong to the oil shale of high ash and low oil yield. The fourth oil shale bed developed in lacustrine bog distributes unsteadily with small thickness. It is belong to the oil shale of middle ash and oil yield.