Source of Chang 10 crude oil in Zhidan area, Ordos Basin, China

Numerous studies on the oil source of Chang 10 reservoir in the Zhidan area were undertaken until now, but still have no definite conclusion. Based on the comparisons and analyses of geochemical parameters between Chang 7 to Chang 9 source rocks and Chang 10 crude oil, it is found that the forming environments of the crude oil in the Chang 10 member are similar to Chang 7 and Chang 9 source rocks, as they occur both in weak reduction environments. C30 hopane(C30H), Ts, C30 rearranged hopane(C30*), Ts/C30H and C30*/C30H range of two types of crude oil in the Chang 10 member are similar to those of Chang 7 and Chang 9 source rocks, respectively. The results show that the crude oil in the Chang 10 member is a mixed product of Chang 7 and Chang 9 source rocks.