nalysis on the gas reservoir forming conditions of Middle Triassic Zhouchongcun Formation in Wuwei depression, Lower Yangtze Basin

By analyzing the relationship between the newly-discovered gas that founded in Middle Trassic Zhougchongcun Fomartion in Wuwei depression, Lower Yangtze Basin and potential source rock, reservoir and cap rock properties, combining with subsurface geological and geophysical data, a further research on material basis and beneficial factors for gas reservior forming was conducted in this paper. The results show that two favorable source rocks, respectively Middle-Upper Permian and Lower Triassic, were deposited in the whole Wuwei depression, with beneficial dissolved pores-fracture dolomite reservoir. The two sets of gypsum beds over 100 meters are the key factors to seal gas reservoirs. The connective fractures and dissolved pores formed by the multi-stage tectonic movements have promoting effects on the migration and storage of natural gas. It is concluded that the favorable gas reservoir forming conditions have a good prospect for conventional gas exploration in this area.