【摘要】 文章目的是研究计算凝析气实际流体临界点的理论算法，文中首先简要回顾了临界点研究的历史及确定临界点的方法。随后对临界点进行确定，临界点是气液一切性质差异均消失的状态，是区分流体类型最重要的参数，并得到了理论和工程应用的广泛验证，目前确定临界点大致有四种方法：①实验测定，通过观察临界乳光现象或记录流体的泡点和露点线；②经验关系式；③通过ＰＶＴ 软件计算流体的泡点和露点线；④利用热力学理论直接计算。由于实验测定临界点费时且费用昂贵，因此如何准确计算临界点一直是人们探讨的难题。当前在深部储层发现了更多的近临界凝析气藏，并且在凝析气藏的生产过程中可能存在复杂的临界相变，因此准确确定凝析气临界点是开发方式选择以及正确分析凝析气藏生产动态的重要基础，具有重要的理论和应用价值。文章结合热力学稳定性理论、五点微分数值算法和基于连续热力学的重组分特征化方法，提供了实际凝析气流体临界点的计算方法和步骤；实例计算表明预测值与实验结果吻合，这进一步证实本方法实用可靠。更多还原

【Abstract】 The purpose of this paper is to investigate the theoretical algorithm of the real fluid critical point of condensate gas.Firstly,the study history and determination methods of critical point are briefly reviewed.The critical point means such a state that all the differences between gas and liquid disappear completely,being a most important parameter of dividing the types of fluid and being widely verified in both theory and practice.Currently,four methods of determining critical point are summarized as follows:①laboratory measurement through examining critical opalescence or recording the bubble point and dew point curves;②empiric relation;③calculation of the bubble point and dew point curves by PVT software;and ④ direct calculation according to thermodynamic theories.Because the critical point measure in laboratory is time consuming and highly expensive,how to accurately calculate the critical point is always a difficult problem.Currently,more near critical condensate gas reservoirs have been found in deep strata and the complex critical phase changes will be able to occur during the production of condensate gas reservoirs.Therefore it is an important basis of electing development scheme and correctly analyzing production performance to accurately determine the fluid critical point of condensate gas,which is of great significance in theory and practice.In combination with the stability theory of thermodynamics and the five point differential numerical algorithm,the theoretical calculation method and procedure of the real fluid critical point of condensate gas are proposed in the paper on the basis of continuous thermodynamic heavy component characterizing method.Through calculation of an example,it is shown that the predicted values are corresponding to the laboratory results,which further demonstrates that this method is useful and reliable.更多还原