Abstract:

Hydrocarbon in South Yellow River Region are derived from Sha 3～4 member source rocks of the neighbouring front Liyuan,Gegangji and Guyang Sags.The analysis result of fluid potential suggests that the main hydrocarbon supplying areas of Baimiao and Qiaokou areas are the front Liyuan and Gegangji Sags;that of Xuji and Machang areas is Gegangji Sag;that of Sanchunji area is Guyang Sag.Westward dounthrown faults resulted in hydrocarbon step migration.Hydrocarbon bearing horizons would get younger each time when transport layer passed through west tilted fault but things would be opposite when the transport layer passed through every eastward downthroun fault,excepting Baimiao area.Oil and gas fields in the South Yellow River Region are distributed annularly near oil generation sag,oil and gas are enriched in the fault block traps of inherited drape structures.

Key words: oil source, migration, accumulation, distribution regularity