| Currently, reservoirs with high temperature high pressure and high content of acid gases have become the alternative energy of our country. It alleviates the contradiction greatly between the development of national economy and the supply of natural gas. Wellbore integrity that related to effectively control formation fluid has become one of the important influencing factors of reservoir development due to the environmental fracture of oil casing, such as SSC and HIC. The corrosion of oil casing, no matter the same block of different oil and gas well or different sections of the same oil and gas well, is different. The may reason is that the solubility of acid gases in liquid solution constantly changes.The main work of the paper:(1)A method is proposed to test the solubility of CO2.(2)A set of device is independently developed, including a manual variable-volume reactor and a gas-liquid separator.(3)The solubility of CO2 in water has been tested under different temperatures, pressures and salinities. And the sensitive analysis is conducted.The results show that the solubility of CO2 in aqueous solution increases with pressure under a certain temperature, while it declines with the increase of temperature under a certain pressure. And the change of solubility tends to be stable with the pressure increasing to a certain degree. Besides, under a certain temperature, the increase rate of CO2 solubility in aqueous solution under low pressure is larger than that under high pressure, and the inflection point appears at 15MPa. The correlation of temperature, pressure and salinity decreases in turn.On the basis of measured and existing data, a new model has been built to calculate the solubility of CO2 in aqueous solution precisely by modifying the parameters of PR EOS. At the same time, its accuracy is higher than that of other models and experimental values. |
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