Experimental and Numerical Investigation of Small Particle Erosion in Gas Dominated Multiphase Flow

Abstract Sand production is a significant challenge in petroleum engineering, and specifically in multiphase gas condensate wells where small amount of liquid is present with the gas. Sand particles entrained in multiphase flow can severely affect the integrity of fluid transportation structures such as pipelines, elbows, and reducers. Traditionally, sand management techniques such as sand screens and gravel packs are used to control sand. However, small particles can pass through these controls. Furthermore, small particles can block a part of the sand screen, causing high velocities in other sections which can cause erosion of the sand screen openings allowing larger particles to pass through which in turn cause more erosion. Furthermore, these small particles are highly susceptible to turbulent regions of flow and can cause severe erosion in these regions. Hence, it is critically important to understand the erosion caused by small particles. This study investigates the effect of small particles on erosion. Small particle erosion is more severe in gas dominated multiphase flows such as annular and mist flows than liquid dominated bubbly and slug flows. A 90-degree standard elbow is used in the experimental and numerical analyses because of its high erosion vulnerability and its importance in pipeline applications. This is because the flow changes direction in this geometry which has complex implications on erosion. This study follows the below mentioned research method: 1) Flow Visualization Study: To understand the flow behavior in bend. 2) Paint-Removal Study: To visualize the progress of paint-removal pattern and to identify the erosion hot spots caused by sand particles. 3) Multiphase Erosion Experiments: To determine the wall thickness loss on identified hot spots using fix-mounted temperature compensated ultrasonic measurement technique. 4) Computational Fluid Dynamics (CFD) Study: To compare erosion patterns with CFD simulations of multiphase flow. Furthermore, the effects of particle size on erosion ratio and its distribution in pipe bends are discussed. The CFD results of larger particles agree better with experimental data than for smaller particles using existing erosion models.