Abstract: Water-soluble released gas is an important part for forming a natural gas reservoir. This paper analyzed the geologic conditions releasing water-soluble gas as necessary, based on the various factors affected solvability natural gas in formation water. By the experiment of physical modeling, a regression equation is obtained for free gas amount liberated from formation water alt saturated natural gas per cubic meters when variations of temperature and pressure. In addition, this paper, taking Araxin gas field in Songliao basin as an example,estimates the contribution of water-soluble gas to forming a natural gas reservoir.

Key words: natural gas, water solubility, temperature, pressure, salinity, simulation