Abstract: The main explorative targets in Minhe basin include Bazhou sag and Yongdeng sag. Yongdeng sag's exploration degree is lower, which is main body of deposition and hydrocarbon source in this area. Through a series of researches on the evolution of basin structure, field outcrop, the seismic interpretation, the analysis and correlation of geological information from Bazhou sag, it is indicated that Yongdeng sag, since the Middle Yanshanian movement, has been in structural high and province of low paleogeothermal field for a long time. Because of its shallow burial target zone, broad developed coastal shallow lake facies, fan delta sand and beach bar sand reservoirs, its physical property is comparatively better, belonging to mid-porosity and mid-low permeability type of reservoir with faulted anticline and anticline traps as well as structural-stratigraphic traps in slop belt area of the easterm Yongdeng sag. The study also shows that the preserved conditions of the traps are good, possessing long-term ability to capture oil and gas due to weak reconstruction to the traps by Himalayan movement and developed faults linked with source rock.

Key words: Yongdeng sag, structural evolution, source rock, trap, reservior characteristic