Effects of production, PVT and pipe roughness on multiphase flow correlations in gas wells

Abstract The importance of gas production has increased as gas represents a clean source of energy. We studied different multiphase flow correlations for gas wells. We collected large database for bottomhole flowing pressure for different flow conditions and well configurations. In total, 32 gas wells were selected and our target was to study the effect of multiphase flow correlations input parameters on the accuracy of the predicted pressure drop. Several important multiphase correlations input parameters were selected for this study. These include condensate to gas ratio (CGR) and water to gas ratio (WGR) which represent the production conditions, API and specific gravity of surface gas (Ɣg) which represent PVT properties and the tubing roughness (ε) which represents the tubing condition. Our method was based on changing the values of these selected parameters by a percentage from its original value and determining the new predicted bottomhole flowing pressure. Consequently, we determined the new error compared to the actual measured bottomhole pressure. We performed 352 cases, and we could obtain the effect of the different parameters on both pressure drop calculations and the selection of the best correlation. Guidelines were developed to explain which parameters are more important to be measured accurately for different conditions.