The aim of this work is to provide a reliable model to predict CO₂ solubility in formation brines using an equation of state (EoS). In this regard, the electrolyte perturbed hard sphere chain equation of state (e-PHSC) was utilized to describe the solubility of carbon dioxide in aqueous electrolyte solutions. Using the ion-specific parameters and a binary interaction parameter between ions and CO₂, CO₂ solubilities in single electrolyte solutions (NaCl, KCl, CaCl₂, MgCl₂, Na₂SO₄, and K₂SO₄) were calculated. Then the model capability was evaluated for CO₂ solubility in mixed-electrolyte solutions. Obtained results prove that e-PHSC EoS can be used for the prediction of CO₂ solubility in mixed electrolyte solutions without any additional adjustable parameters. Finally, the predictive capacity of the e-PHSC EoS was explored for two synthetic formation brines up to 423 K. The result shows that the CO₂ solubility in formation brines can be efficiently predicted using e-PHSC EoS.

这项工作的目的是提供一个可靠的模型来使用状态方程 (EoS)预测地层盐水中的CO ₂溶解度。在这方面，电解质扰动硬球链状态方程（e-PHSC）被用来描述二氧化碳在电解质水溶液中的溶解度。使用离子特定参数和离子与 CO ₂之间的二元相互作用参数，计算了单一电解质溶液（NaCl、KCl、CaCl ₂、MgCl ₂、Na ₂ SO ₄和 K ₂ SO ₄）中的CO ₂溶解度。然后针对 CO ₂评估模型能力在混合电解质溶液中的溶解度。获得的结果证明，e-PHSC EoS 可用于预测混合电解质溶液中的 CO ₂溶解度，而无需任何额外的可调参数。最后，探讨了 e-PHSC EoS 对两种高达 423 K 的合成地层盐水的预测能力。结果表明，使用 e-PHSC EoS 可以有效地预测地层盐水中的 CO ₂溶解度。