2-PHASE FLOW CORRELATIONS AS APPLIED TO PUMPING WELL TESTING

In a pumping-well buildup test, computation of bottom-hole pressure (B HP) and flow rate (BHF) requires the use of a two-phase flo w correlat ion for estimating the gas void-fraction or holdup along the pipe leng th and shut-in time. Various correlations are available to perform thi s task. The purpose of this work is to review these two-phase correlat ions and to provide an objective evaluation. This analysis is necessit ated by the fact that considerable differences in BHP and BHF may occu r-depending upon the correlation used-in wells with long pumping liqui d columns or those that have high gas/liquid ratio production. Consequ ently, a potential exists for obtaining different reservoir parameters from transient interpretation. Using laboratory data for two-phase fl ow in annular geometry, relative strengths of these correlations are e xplored. Our own data and those of others (a total of 114 points) are used in this comparative study. For static liquid columns, the correla tions of Hasan-Kabir, Gilbert, and Podio et al. provide acceptable agr eement with experimental data, exceptions being the Godbey-Dimon and S chmidt et al. correlations. In contrast, for the moving liquid column scenario, as in a buildup test, the Hasan-Kabir model provides the bes t agreement with the dataset used in this work. A basis for smoothing the bubbly/slug transition boundary is given for the Hasan-Kabir metho d, together with a field example.