The influence of 18α(H)-neohopane on source rocks in Yanchang formation, Ordos basin

ABSTRACT

Rock extracts and oil samples has been detected high abundance of 18α(H)-neohopane fromYanchang Formation in Ordos Basin. The results showed that the black mudstone was deposited in anoxic condition of semi-deep or deep lacustrine facie has low abundance of 18α(H)-neohopane in Chang 7 member. The dark mudstones with high abundance of 18α(H)-neohopane in Chang 9 member that they were deposited in suboxic condition of shallow lacustrine facies. The origin of high concentration of 18α(H)-neohopane have relationship with the sedimentary environment and organic matter type. The geochemical significance of 18α(H)-neohopane can effectively solve the oil-source correlation of the research area.

KEYWORDS:

• 18α(H)-neohopane
• source rock
• Yanchang formation
• depositional environment
• oil-source correlation

Acknowledgments

We thank the State Key Laboratory of Sichuan Province Key Laboratory of Natural Gas Geology, Southwest Petroleum University for assistance in data and sample collection. Funding for this research was provided by programs from Open Fund (PLNxxxx) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University(CN), scientific research starting project of SWPU(No. 2014QHZ010).