松辽盆地十屋断陷水动力场与低压气藏的关系

松辽盆地十屋断陷在1250m以上为正常压实带,1500m以下为低压带,其间为压力过渡带,其对应的水动力场分别为自由水交替带,交替停滞带和交替阻滞带。由于交替阻滞带和交替停滞带天然气散失量大于地下水补给量,且愈下地下水补给量愈小,从而导致随埋深增加压力系数降低,形成低压气藏。交替阻滞带和交替停滞带中的气层才是该区的主要产气层。

HYDRODYNAMIC FIELDS AND LOW-PRESSURE GAS POOLS IN SHIWU FAULT-DEPRESSION,SONGLIAO BASIN

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.