Tight sandstone gas in rift basins is a new play concept for exploration.This paper takes the Songliao Bbasin and the Bohai Bay Basin as case areas to systematically investigate the mechanisms for gas accumulation and enrichment in tight sandstones.The reservoir characteristics of tight sandstone gas in rift basins have been studied

which are different from those of craton basins.As to gas accumulation mechanism

it is demonstrated that multiple factors have accelerated the generation of gas by source rock

and multiple sediment provenance have ensured deposition of favorable reservoirs.Both the long gas migration distance and tightening of the reservoir before gas charge favors gas accumulation in multiple sections over large areas.For the enrichment controlling factors

it is concluded that the distribution of gas pools and source kitchens are located along the faulted troughs

the reservoir quality is controlled by facies and tectonic belts

while the vertical distribution of flowable gas sections is controlled by development of secondary porosity zones.Finally

the exploration potential and future exploration concepts of these two basins is analysed.