Exploration potential of Chang 9 member, Yanchang Formation, Ordos Basin

Abstract

New discoveries have been achieved in the exploration of the Yanchang Formation Chang 9 member. This article discusses the exploration potential of the Chang 9 member from the hydrocarbon source rock condition, reservoir condition, and the pattern of hydrocarbon generation and storage. The Chang 9 member develops high quality hydrocarbon source rock (the mean TOC is 4.36% and R0 is 0.66–1.01%), has superior hydrocarbon-offering capacity, and the total resources surpass 402 million tons of oil. Delta front subaquatic distribution channel sandstone and river mouth bar sandstone can be laterally connected as a complex and the main reservoir space is made up of the remnant primary pores. The reservoir capability is good. The member develops three types of plays: self-generation and self-storage, below-generation and above-storage, above-generation and below-storage. The exploration potential of the self-generation and self-storage is best with dark mudstone or oil shale as the source rock and sandstone as the reservoir. Key words: Ordos Basin, Chang 9 member, source rock condition, reservoir condition, play, exploration potential