Abstract:

In Shiwu fault depression of Songliao Basin, sediments buried shallower than 1 250 mbelong to normal pressure zone;that deeper than 1 500 m belong to low-pressure zone sediments between above mentioned zones are in tranzitional zone. Hydrodynamic fields corresponding to these zones are respectively free replacing zone,obstructive replacing zone and irreplacing zone. The amounts of gas losses in the obstructive replacing and irreplacing zonesare greater than that of subsurface water leakage recharge,and the deeper the gas buried,theless the subsurface water recharge amount would be. This resulted in the decrease of , essurecoefficient with the Increasing of buried depth,and the formation of low-pressure gas pools. Itis considered that gas reservoirs in the obstructive replacing zone and irreplacing zone are themain productive beds of the region.