SIMULATION OF INTERMITTENT FLOW IN MULTIPHASE OIL AND GAS PIPELINES

This paper reviews recent advances made in the computational simulation of intermittent flow, and in particular the slug flow regime in pipes carrying multiphase fluids. The methodology is based on the transient, one-dimensional two-fluid model equations that are solved numerically using fine grids and small time steps to capture the hydrodynamic instabilities that initiate waves and slugs. The capture of slugs is achieved in a completely automatic manner and leads to remarkably accurate predictions of average slug characteristics when compared to data from laboratory experiments. More astonishing is the ability of the one-dimensional model to capture stochastic nature of slug flow. In industrial applications involving pipelines extending several kilometres, special numerical procedures must be adopted to speed up the computations to keep them within practical time constraints.