Abstract: Sinopec’s licensed block in the western margin of the Junggar Basin is predominantly distributed in the Chepaizi uplift. Since it is far from oil sources and has complicated geologic conditions, the block is less explored with protracted exploration cycle. To clarify the hydrocarbon potential in the block and thereby provide effective guidance for future exploration operations, in-depth researches were conducted based on the distribution of formations and sedimentary facies within the Chepaizi uplift to analyze oil sources, reservoir-cap rock assemblages and other reservoir conditions systematically. Research results show that the study area has favorable petroleum geologic conditions for hydrocarbon accumulation. As the final destination for long-term migration of hydrocarbons, the block has great hydrocarbon potential. Through correlation of oil sources and investigation on accumulation periods, the fault-blanket sandstone conductivity was determined, and the hydrocarbon accumulation model characterized by “hydrocarbons supplied by lateral sources, with faults providing vertical conductivity and blanket sandstones providing horizontal conductivity, and accumulated at blanket margins” was established. In accordance with these conclusions, drilling operations were successfully deployed, and a series of discoveries with commercial values were obtained.

Key words: hydrocarbon potential, fault-blanket sandstone conductivity, accumulation model, Junggar Basin, Chepaizi uplift