Equations of state (EOS) can be used to construct solubility model of gases in aqueous solutions. A thermodynamic model is introduced to predict the solubility of methane(CH4), hydrogen sulfide (H2S), and carbon dioxide (CO) in pure water and in aqueous salt solution over a large range of temperature, pressure and salt concentrations (273-523K, 1-2000 bar, 0-6m for CH4; 273-500K, 0-200bar, 0-6m for H2S; 273-533K, 0-2000bar, 0-4. 5m for CO2), with accuracy equivalent to that of reliable experiments. With the specific interaction approach, this model is not only able to predict gas solubility in NaCl solutions, but also other more complex systems, such as seawater and geothermal brines, without fitting experimental data from these systems. The model finds wide applications in the study of solubility of gases in nature aqueous solutions with different temperatures, pressures and salt conditions, and can also analyze the PVTX conditions of fluid inclusions, calculate the immiscibility of mineralization fluids, the minimum conditions of CH Hydrate's formation, and even CO2 sequestration. Online calculation of the solubility of these gases is available at; www. Geochem- model.%本文介绍一个通过状态方程和特定粒子相互作用理论建立起来的气体在水溶液中的溶解度模型,用以计算气体(CH4、H2S、CO2)在纯水和含盐水溶液中的溶解度、流体包裹体的均一条件、成矿热液沸腾、流体不混溶性、水合物形成条件、CO2地质储藏量等.该模型不仅重现了上百套实验数据(约8000多个数据点),而且具有很强的外延能力.因此适用宽广的温度、压力和盐度范围(CH4:273～523K,1～2000bar,0～6m;H2S:273～500K,0～200bar,O～6m;CO2:273～533K,0～2000bar,0～4.5m),而且精度高、形式简洁.由于使用状态方程和特定粒子相互作用理论相结合的方法,这一模型在无需实验数据的情况下能够拓展到诸如海水和地下热卤水等更为复杂的体系.该模型在国际上得到日益广泛的应用,已被许多国家的同行用以多方面的研究工作,如计算CH4、H2S和CO2气体在水、卤水和海水等天然水溶液不同温度、压力和盐度条件下的溶解度(即水溶液中最大允许的气体含量),分析矿物流体包裹体的PVTX条件(根据包裹体中气体的总含量和均一温度,用该模型就会很方便得到均一化压力,在此基础上还可以迸一步通过状态方程得到密度和等容线)、计算成矿流体的不混溶性或沸腾点、计算CO2地质储藏量、实验校正等方面.相关研究可进行在线计算:www.geochem-model.
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