New correlations for critical and subcritical two-phase flow through wellhead chokes

Several correlations of critical and subcritical two-phase flow through wellhead chokes were evaluated to test their application to Middle East oil fields. Two groups of correlations describing two-phase flow through wellhead chokes were examined. The first group involved simple empirical equations similar to those of Gilbert((1)). Two new correlations were proposed: one for critical and the other for subcritical flow regimes. The second group comprised derived equations of two-phase flow incorporating PVT properties. PVT correlations developed for the Middle East crudes were employed. These correlates were tested for a wide range of field data obtained from several Middle East countries. Selection of best correlation was justified by statistical error analysis, range of validity, and number of involved variables to be measured in the field. Our simple version of correlations provided more accurate results than any other correlation involving the same variables. Incorporating of the PVT correlations for produced fluid properties of the Middle East oil fields improved the accuracy of the derived models. The developed correlations were useful for accurate prediction of choke performance of the Middle East oil wells. The proposed empirical correlations are applicable for various types of reservoir fluids, including black oil, volatile oil, and gas condensate fluids. These correlations do not require knowledge of PVT properties of the produced fluids.