Prediction of liquid holdup in horizontal gas wells based on dimensionless number selection

Abstract

Pressure gradient prediction is crucial in gas well analysis. The experiment is the most effective method of understanding the flow characteristics in horizontal gas wells. The greatest difference between experimental and high-pressure conditions is gas density, which could cause the established multiphase correlations unreliable when they are applied to high-pressure gas wells. Similarity numbers are widely employed in predicting flow behavior. Nevertheless, few studies focused on this area. Additionally, gas wells are characterized as high gas-liquid ratio; the majority empirical correlations were developed for oil wells, which have a more consideration in low gas-liquid ratio, influencing the precision of gas well models. An experimental examination of gas-liquid flow has been carried out in this study. First, the experimental test matrix was designed to meet each flow pattern. Next, the effect of gas velocity, liquid velocity, pipe diameter, water-cut, and inclined angle on liquid holdup was explored. Subsequently, the similarity numbers suggested have been investigated and assessed for pressure scaling up. Finally, a comprehensive model was established, which was developed to forecast pressure gradient in gas wells. Field data was supplied to assess the new correlation. The results demonstrated that the Duns-Ros and the modified Duns-Ros dimensionless numbers were improper for pressure scaling up, whereas the Hewitt-Robert Number performs best. Based on field data, the new correlation with Hewitt-Robert Number was superior to extensively employed pressure drop correlations, showing that it can deal with predicting pressure gradient in gas wells.