Assessment and sensitivity analysis of multiphase flow pipeline models against experimental and field data

Transient multiphase pipeline simulators are seeing increasing application for live computation of oil and gas production pipeline and process flows. This study considers the performance of Wood Group's Virtuoso tool and three other commercially available simulators used widely in the industry, on an extended set of field data from a large gas-condensate pipeline with three-phase flow. A steep escarpment strongly influences the dynamics of pipeline pressure, and liquid content and outlet rates; production rates span the region of transition between separated and slug flow regimes. ‘Out-of-the-box’ model predictions of pressure drop can differ from measured values by 20% or more. While model predictions of liquid holdup agree reasonably well – both mutually and against experimental data – for small-diameter pipes at gentle inclination, predictions vary by 50% or more under field conditions. The extent of scatter in predicted holdup is a large fraction of available slug catcher capacity. Analysis indicates that pressure and liquid volume predictions are sensitive to flow regime determination, specifically via the interfacial friction factor and the holdup at which slugging initiates; pressure prediction error can be reduced by 50% through moderate adjustment of associated modeling parameters. These aggregate assessments of model performance suggest that field-specific model tuning remains necessary to achieve the level of prediction accuracy demanded by online systems used for liquids management, forecasting, and pipeline integrity monitoring.