A Comparative Study among Empirical Correlations for Pressure Drop Calculations in Vertical Wells

Abstract

In this study, since the estimation of the pressure drop in vertical wells is quite important for several practical applications, a comparative study of pressure drop models and correlations has been done by using a commercial software. When calculating multiphase pressure drops in oil wells, there are several models available to do this. Each correlation was developed for a specific set of conditions which makes the applicability of any correlation outside the respective set of flow conditions questionable. In addition, models can have different complexities and, consequently, different calculation accuracies. The objective of the present study is to investigate the expected accuracies of three models. Two wells have been selected which are producing from different reservoirs having oil with similar API. In order to evaluate each correlation or model, the values of both measured and predicted pressure drop were analysed. It has been found also that the smallest errors were obtained by Beggs and Brill model despite the fact that the average absolute error is high for this particular case. Therefore, Beggs and Brill model outperformed Duns & Ross and Orkiszewski for the two wells studied under the specified conditions. It is recommended to perform this study amongst pressure drop correlations and models at early stages of production. Also, it is recommended to investigate as many wells as possible producing from the same reservoir and perform sensitivity analysis on some possible influential factors.