Abstract: It has a great potential for oil and gas resources exploration in Qigu Formation of Fudong slope area, Junggar basin, and the exploration and development process has been restricted due to a lack of system understanding of sedimentary facies. In order to gain a detailed understanding of the sedimentary facies and identify the favorable reservoir facies, many data, such as field outcrops, cores and sections observation, analysis on heavy minerals and geochemistry, drilling, logging, and seismic data were used. The results show that: The provenances of Qigu Formation are the northern Karameili Mountain, the southern Bogda Mountain, and the eastern Beisantai salient. A braided delta deposit dominated the Qigu Formation, which can be divided into two subfacies (delta plain and delta front) and several microfacies based on sedimentary characters. Based on seismic attributes and sand contents, the favorable sandbodies are characterized. Favorable sandbodies and oil-bearing properties in Qigu Formation are predicted through space distribution analysis of sedimentary facies. Underwater distributary channels in the initial stage of Qigu Formation, distributary channels near deep fault or denudation areas are favorable reservoir facies belts for the forming of lithological accumulations.

Key words: Junggar basin, Fudong slope area, Qigu Formation, sedimentary face, favorable reservoir facies, oil and gas, lithological oil and gas reservoirs