Determining the phase state of hydrocarbon mixtures based on cubic equations of state is an integral part in modeling of technological processes that accompany oilfield development. When using these equations, it is necessary to determine critical properties of each component or fraction included in the mixture. The quality of the input data in the form of correctly specified values of critical properties affects the reliability of the simulation results. The critical properties of pure components such as methane, ethane, etc. are reference data, however, the libraries of the most well-known software systems have discrepancies in critical properties values both with reference data and with each other. The properties of fractions are calculated on the basis of the use of various correlation dependencies, while there are no universal correlations for determining the properties of fractions. In this regard, it becomes necessary to compare the values of properties calculated by correlations, reference data, and software product libraries.
The article presents the results of an analysis of the critical properties of individual substances given in the reference literature, the properties of fractions calculated by correlations, as well as the values used in commercial software, in order to determine the highest quality data set. Based on conducted analysis recommendations were made on the use of certain correlations which will allow to obtain reliable results in modeling phase equilibrium and calculation of PVT properties of fluids. The results can be used to develop tools for modeling technological processes, in particular, in the RN-SIMTEP corporate software package.
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