Abstract: The Changxing Formation and Feixianguan Formation in Sichuan Basin are enriched in reef oil and gas resources, which are distributed in the areas of the platform and the platform margin slope in northeast Sichuan Basin. This region is an important area for exploration. The reef-bank gas reservoirs in Longgang and Yuanba areas of northeastern Sichuan Basin have good conditions for accumulations. Distribution of the gas reservoirs are controlled by a number of factors, such as the sedimentary facies, reservoir development characteristics, dolomitization and tectonic action. The important controlling factors for abundance and high production also include the variety of gas reservoirs, fractural development degree and structural activity. At present, the exploration results in Yuanba area are better than those in Longgang area, because the reef-bank scale is larger in Yuanba area with a weaker heterogeneity. The area is less affected by the tidal channel systems. Therefore, Yuanba area has better conditions for accumulation and abundance. Longgang area is apparently affected by the structural effect and tidal channel systems. The reservoirs are strong in heterogeneity and experience strong adjustment and transformation in later periods. The area is characterized as a number of isolated reef beach reservoirs. The study indicates that the efforts should be focused on seismic data quality, further research on the sedimentary subfacies, reservoir prediction and oil and gas testing to improve exploration of reefbank gas reservoirs in Longgang and Yuanba areas. The reef-bank bodies in the platform peripheral area, with a large thickness and a large area, should be the important targets for exploration.