摘要
Ordos Basin is a large inner continental sedimentary basin in China. The authors collected the crude oil samples from different regions of Maling oilfield and source rocks in the Ordos Basin, and analyzed biomarker compounds in the oils and source rocks. In this paper, the formation conditions of oil reservoir in Maling oilfield, such as source rock, reservoir rock,oil migration, traps and accumulation,were systematically studied, and its forming mechanism was discussed dynamically. The results show that crude oil of Maling oilfield was derived from the Yanchang Formation source rocks. Reservoir rocks are mainly the Low Jurassic Yanan Formation fluvial channel sandstones, while coal seam, carbonaceous mudstone and mudstone constituted the cap rock.