Parametric investigation of sand erosion rates in gas pipeline bends under typical industry conditions using simplified method

Abstract

ABSTRACT The production and transport of sand from oil and gas wells into production and transport facilities results in flow assurance and structural problems. A critical operational issue is the erosion of oil and gas facilities by the suspended sand particles, particularly around flow diversions. This study investigated the effects of four key parameters, namely particle size, sand load, fluid velocity, and fluid density, on the rate of sand erosion in gas pipeline bends using DNV GL-RPO501 and Star CCM+ software package, a Computational Fluid Dynamics (CFD) tool developed by CD – adapco. Sand concentration and particle sizes both cause a linear increase in erosion rate. The particle sizes affected the location of maximum erosion. The single and mixture component gas densities showed an inverse linear and non-uniform relationship with erosion rate. The CFD models underpredicted erosion rates by about 90% compared to the experimental data. An exponential relation exists between the erosion rate and gas/sand velocity especially velocities above 10 m/s. The CFD method largely predicted more realistic values of erosion rate than the DNV GL-RPO501 due to some oversimplified assumptions made in the latter. The CFD tool however compared favorably with the DNV GL-RPO501 at high velocities. Both CFD and DNV GL-RPO501 models are recommended for erosion studies at higher fluid velocities, while the CFD modeling is better at lower velocities by incorporating drag and inertial forces which are important forces at low gas velocities. The particle and fluid velocity affected the sand erosion rate more than the other factors considered. However, future studies should consider modeling erosion rates under transient conditions and investigate the effects of various turbulence models. Different sand mixtures with various particle sizes and other gases such as CO2 should be considered.