Multiphase friction calculation peculiarities based on models implemented in the "d-Flow" software package

In order to ensure efficient and safe operation of oil and gas fields, a tool is required to design production wells and surface infrastructure. It is important to take into account the physical processes that occur during production, as well as fluid properties and phase transitions. The "d-Flow" software package enables the creation of a comprehensive field model based on geological and field data to calculate hydraulic losses of pipelines and forecast hydrocarbon production. The fluid flow modelling is based on the calculation of multiphase friction with the wall of a well or a pipeline.                The article discusses the implementation of four friction models: the Beggs-Brill model, the Gray model and its modification, and the Mukherjee-Brill model. The purpose of this work is to compare the predictions of friction models with the results obtained using commercial realizations of the same models. The results of the Schlumberger PIPESIM hydraulic simulator calculations were used as a benchmark for comparison with the "d-Flow" models. Numerical experiments were conducted to investigate two-phase flow under varying well geometry and flow regimes. The models used were compared, and the results showed that the predicted liquid holdup had an average relative error of 0.06%. In some cases, the error was as low as 0.02%. The predicted cumulative pressure drop in the well did not exceed 0.34% for all considered models. Based on the comparison results, we conclude that the "d-Flow" software package is suitable for calculating pressure drop in wells of different geometry and surface networks.