Abstract: Chaoshui basin is the largest Jurassic basin in the Gansu Corridor, in which the hydrocarbon generation indices in the Middle-Lower Jurassic coal seam and lacustrine shale are similar to those in Tuha basin, but the area of hydrocarbon generating sags and the thickness of source rocks are smaller than those in Tuha basin, and its petroleum resources account for 1/5of the total in this basin. The Qingtujing group of Middle-Lower Jurassic belongs to a low-porosity and low-permeability reservoir. Chaoshui basin is characterized by lacking of anticline structural zone formed in Himalayan movement and the fault-block and faulted anticlinal traps. Although the scale of this basin is smaller than that of Tuha basin, the Qingtujing reservoir with petroleum resources of about 2×108t has been found. It is concluded that Chaoshui basin still has good prospects for hydrocarbon exploration.

Key words: Chaoshui basin, Jurassic, petroleum exploration, prospect