Abstract: Yinggehai basin is a young Cenozoic sedimentary basin with high geothermal and overpressure, few faults, many diapirs, strong action of thermal fluid. There are specific migration and accumulation principles in the extend and transform sedimentary basin contrasting with the fault basin. Based on ideas of the key factors to control the forming of the natural gas reservoir, the viewpoints of the dominant principle on natural gas accumulation of mud-fluid diapirs in Yinggehai basin were presented by analyzing the forming and the distribution of the natural gas reservoirs in the basin. The natural gas accumulates in the diapirs area in the central depression and was trapped on the top, both sides and around the mud-fluid diapirs. It indicates that the slope belt near the depression is not always the most promising target area in the depression according to this viewpoint. It provides a new clue that only the belts and traps in the basin meeting with the dominant principle may accumulate the natural gas in the Yinggehai basin. It shows that the significance of exploration on natural gas in Yinggehai basin.

Key words: Yinggehai basin, the natural gas, the dominant principle on natural gas accumulation of mud-fluid diapirs, significance of exploration