Expert Solution for Effects of Input Parameters on Multiphase Flow Correlations

Abstract

Oil and gas production represents essential source of energy. Optimization of oil and gas production systems require accurate calculation of pressure drop in tubing and flowlines.

  In this work, different multiphase flow correlations were investigated to determine the effects of their input parameters on accuracy. The study followed several steps including the collection of a large database of bottomhole flowing pressure for different flow conditions and well configurations. 33 oil wells and 32 gas wells were selected and the target was to determine the effect of multiphase flow correlations input parameters on the accuracy of the predicted pressure drop.

  Production data, PVT parameters and tubing roughness are the main input parameters that are believed to affect multiphase pressure drop calculations. A commercial software was used to build different well models. The method was based on assuming new values of these selected parameters using a percentage from its original value and calculating the new predicted bottomhole flowing pressure. The deviation compared to the actual measured bottomhole pressure was determined in every case. A total of 715 cases were investigated and the effect of different input parameters on both the pressure drop calculations and the selection of the best correlation were determined. The results were integrated into a rules-based expert system.

  A new set of data was used to validate the expert system. Calculations for 220 cases from 20 new wells were performed and the expert system was found to predict the best correlation with success rate of 80%. Finally, VBA-Code was developed to show which parameters have a high impact on the pressure drop calculations to be carefully measured or calculated for different flow/well conditions.