Abstract:

This paper analyzes some geochemical information  of Jurassic reservoir in the Yanqi basin,which includes crude oil physical property，pyrrolic nitrogen compounds and isotopic age of autogenetic illite, and also discusses the oil and gas migration direction.The result indicates that these geochemical parameters show a regular variation decreasing gradually from south to north in plane and from deep to shallow in the vertical. Based on this analysis, it is concluded that Jurassic oil and gas migrated from south to north in the lateral and from deep to shallow in the vertical: Oil and gas injected firstly into Baonan reservoir, secondly into Baozhong and Baobei reservoirs laterally, and migrated from Badaowan Formation to the reservoirs of Sangonghe Formation and Xishanyao Formation vertically.

Key words: Yanqi basin, crude oil physical property, nitrogen compound, isotopic dating of autogenetic illite, oil and gas migration