An experimental investigation was carried out to investigate the behavior of gas-liquid flows in a large diameter pipe with high flow-rates. The objectives are to experimentally evaluate two-phase flows in vertical pipes of large diameter and collect information to verify the accuracy of wellbore flow models applied to Worst-Case Discharge (WCD) calculations.

The flow correlations developed for small diameters, used on Worst-Case-Discharge calculations, show errors of more than 100% compared to the experimental data for large-diameter pipes. However, for low gas liquid-ratios, the there is a reasonable agreement between experimental data and simulation results for all wellbore flow models tested, with errors lower than 10%. This study uses the experimental data to provide guidance on how to improve these flow correlations and proposes how to use the flow models to obtain improved results on WCD calculations.