Abstract: The Shuixigou group of Jurassic in Tuha basin has geologic conditions for forming large-area tight sandstone gas reservoir. Long-term and great amount gaseous hydrocarbon generation and expulsion provide good preconditions for forming tight sandstone gas reservoir. The source rocks and reservoir rocks appear in interbedded contact relations which are favorable for inter-source gas accumulation in the tight sandstone reservoir. The gas migration and accumulation in the tight sandstone reservoir are quite different from those in conventional gas reservoir. In condition of piston-like gas charging, the water cut in tight sandstone gas reservoir is obviously high, and high or low pressure anomaly occurs. Under effective assemblages of the source and reservoir rocks, the south slope and north piedmont thrust belt in Tuha basin are favorable areas for exploration of tight sandstone gas reservoirs.

Key words: Tuha basin, tight sandstone gas reservoir, Shuixigou group, coal measure source rock, gas accumulation feature