Numerical Modeling of Sand Production Using Coupled DEM-LBM

Document Type : Research Article

Authors

1 Faculty of Engineering, Ferdowsi University of Mashhad

2 Civil Eng. Department, Faculty of engineering, Ferdowsi University of Mashhad

Abstract

Sand production, which is a critical phenomenon in the oil and gas well walls, is numerically investigated in this research. The main goal is to study the particulate mechanism of sand ‎‎production in unbonded assemblies and examine the effects of stress level and pressure drawdown on the ‎model. Discrete Element Method (DEM) in combination with the Lattice-Boltzmann Method (LBM) is selected to simulate the fluid flow ‎through porous media. The Immersed Moving ‎Boundary method is used to couple the DEM and LBM methods. After developing a computer ‎program, a 2D model of sand production is simulated under radial flow. The simulation results show that as the confining stress ‎increases, the number of produced particles and sand production rate increases. After the initiation of sand production, the sanding rate decreases in all models ‎due to the formation of sand arches around the central hole. These sand arches are weak and ‎usually unstable, and after the collapse of every arch, the new arch is formed and replaces the ‎previous one with a larger diameter. The results also show that the pressure drawdown has a negligible effect on sand production at low stress levels. However, at high stress levels, the increase of pressure drawdown significantly increases the number of produced particles (a 50% increase in pressure led to more than twice produced particles). It is also found that the 2D coupled DEM-LBM is a ‎promising tool to predict the mechanism that governs sand production and its main influencing ‎factors‎.

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