ACCURACY OF SACHDEVA’S CHOKE MODEL FOR PREDICTION GAS AND LIQUID RATE OF IRANIAN GAS CONDENSATE WELLS

Flow through a surface choke can be either critical or subcritical. Most of the correlations available to petroleum engineers are for critical flow but in lots ofhigh rate gas/condensate wells subcritical flow occurs in large choke sizes. Sachdeva’s multiphase choke flow model has capabilities of predicting criticalsubcriticalboundary and liquid and gas flow rates for given upstream and downstream pressures. Accurate modeling of choke is vitally important for apetroleum engineer in production from reservoirs.In this study, the accuracy of the Sachdeva’s choke model was evaluated using data from gas condensatewells in Iran. Comparisons of the results from the model and field measurements indicate that Sachdeva’s choke model generally under-estimates gas and condensate flow rates. Based on measurements from 101 gas condensate wells .it was found that the model underestimatesgas rate and liquid rate by as much as 35% and 65%, respectively. The investigation further went on to improve the performance of Sachdeva’s chokemodel. It was found that the error of the model could be minimized using of choke discharge coefficient (CD). For gas condensate wells, the error in gas flow rate calculations can be minimized using CD = 1.048 However, the error in liquid flow rate calculations for condensate wells is minimum when CD = 1.62.