基于G^(E)混合规则的SRK-CPA状态方程预测CO_(2)在地层水中的溶解度

Prediction of the solubility of CO_(2) in formation water using SRK-CPA equation based on G^(E) mixing rule

基于改进的缔合流体理论模型,利用SRK-CPA状态方程结合Huron-Vidal混合规则,建立了一个4参数热力学(iCPA-HV)模型,模型中H_(2)O-CO_(2),H_(2)O-NaCl,CO_(2)-NaCl的可调参数(α,E_(ij),E_(ji),F_(ij))由拟合实验数据获得。模拟结果表明,在预测CO_(2)-H_(2)O-NaCl混合溶液体系中的CO_(2)溶解度时,与SRK-HV模型相比,iCPA-HV模型整体预测效果更佳,平均绝对相对误差(AARD)为3.25%,低于SRK-HV模型的AARD(31.94%),为精确预测CO_(2)在NaCl地层水中的溶解度提供了一种新方法。

According to the model of improved association fluid theory,a four-parameter thermodynamic(iCPA-HV)model was established by using the SRK-CPA equation based on Huron-Vidal mixing rule.The adjustable parameters(α,E_(ij),E_(ji),F_(ij))of H_(2)O-CO_(2),H_(2)O-NaCl,CO_(2)-NaCl in the model were obtained by the fitting of experimental data.The results indicate that the overall prediction effect obtained by newly proposed iCPA-HV model is better than that obtained by the SRK-HV model when it is applied to predict the solubility of CO_(2)in the mixed CO_(2)-H_(2)O-NaCl system.The average absolute relative deviation is 3.25%,which is much lower than that of SRK-HV model(31.94%).The method described above provides a new solution to accurately predict the solubility of CO_(2)in NaCl formation water.