Critical two-phase flow through wellhead chokes of Middle-East oil wells

Accurate prediction of multiphase flow through chokes is required for modern production design and optimization of oil well performance. Most of the Middle-East oil wells are uniquely characterized with high production rates. Several correlations that relate the choke size with other variables involved in the multiphase flow phenomena have been proposed in the literature. The validity of these correlations for Middle-East oil wells has been assessed in this study. A new correlation has been developed to describe the choke performance of the Middle-East oil wells. The proposed correlation is similar to the Omana-type correlations based on dimensional analysis. This correlation was examined against a wide range of well-test data collected from various oil fields in Egypt, Kuwait, Libya, and other Middle-East countries. Statistical analysis was used to compare the accuracy of the results obtained from the new correlation with those from other correlations. The effect of different PVT correlations on the predictive accuracy of the fluid-now equations has also been investigated. These properties include the surface tension of the gas/oil system, gas compressibility factor, solution GOR, and oil volume factor. The developed correlation provided highly accurate results compared to the other existing correlations. This correlation is applicable for critical flow conditions and requires knowledge of the PVT data. This study showed that the use of different PVT correlations resulted in slight variation in the accuracy of the developed correlation. Further analysis has been conducted in the present study on the Gilbert-type empirical correlations. Results emphasized the linear relationship between flow rate and upstream pressure for critical flow.