A calculation method of dew-point pressure of gas condensate reservoir

A large data bank of more than 700 gas-condensate samples collected from literatures and experiments was established. On this basis, empirical correlations equations of state commonly used to calculate dew-point pressure (DDP) were evaluated, a new model for estimating DPP was proposed, all the empirical correlations and Peng-Robinson state equation were compared, and sensitivity of parameters was analyzed. The current standard used to identify gas condensate isn't accurate enough. The Peng-Robinson state equation has no unique solution and is affected by multiple factors such as the characterization relation of C7+ components and the splitting scheme. The Nemeth-Kennedy correlation has the highest accuracy when applied to the data bank established in this study, followed by Elsharkawy correlation and Godwin correlation, Shokir correlation can't be used to samples without C7+ components and thus is the lowest in accuracy. The newly proposed model has an average absolute error, root mean square error and coefficient of determination of 7.5%, 588, and 0.87, respectively, and is better than the above four correlations statistically. The proposed model was proved accurate and valid by comparing its results with experimental data and the results of simulation with Peng-Robinson state equation. © 2020, The Editorial Board of Petroleum Exploration and Development. All right reserved.