Abstract: In Kolzhan area, land sources, carbonate rock and mud shale of Devonian and Lower Carboniferous are the main source rock, and they feature in thick source rock, high abundance of organic matter and favorable hydrocarbon conditions. Carbonate rocks with strong heterogeneity are major reservoirs. In addition, two sets of source-reservoir-cap assemblages combinations of self-storage reservoir and below generation-up reservoir developed. Kungurian salt of Permian is of the vast majority of the high-quality regional cover in the basin, of which traps are dominated by structural and stratigraphic traps and reservoirs are mainly distributed in subsalt anticline structure. Through the analysis of the forming conditions of the basin, with well K drilling in Kolzhan area, it is shown the subsalt hydrocarbon accumulation is dominated by the structural traps and reservoirs in the area, and to find effective traps is the direction of exploration for oil and gas in the area in the future.

Key words: carbonate rock, forming condition, structural trap, reservoir forming pattern, Kolzhan area, Pre-Caspian Basin