Abstract
The primary motivation of this paper is to investigate the sand-retention mechanisms that occur at the opening of sand filters. Various retention mechanisms under various conditions are explored that have a particulate flow with a low concentration of sand particles (called slurry flow) such as particle shape, size, and concentration. The computational fluid dynamic (CFD)–discrete element method (DEM) model is applied to predict the retention mechanisms under steady flow conditions of the well-bore. By using coupled CFD–DEM (CFD to model the fluid flow, and DEM to model the particle flow), the physics involved in the retention mechanisms is studied. The coarse grid unresolved and the smoothed unresolved (refined grid unresolved) coupling approaches implemented in STAR-CCM+ (SIEMENS PLM) are used to transfer data between the fluid and solid phases and calculate the forces. The filter slots under investigation have different geometries: straight, keystone, wire-wrapped screen (WWS) and seamed slot and the particles are considered with different shapes and different aspect ratios and size distributions. The flow regime is laminar in all simulations conducted. The CFD–DEM model is validated from the perspectives of particle–fluid, particle–particle, and particle–wall interactions. Verification of the CFD–DEM model is conducted by mesh sensitivity analysis to investigate the coupling resolution between the CFD and DEM. By simulation of numerous slurry flow scenarios, three retention mechanisms including surface deposition, size exclusion, and sequential arching of particles are observed. However, the concentration of particles is too diluted to result in multiparticle arch formation. In the simulations, various conditions are tested to give us an insight into the parameters and conditions that could affect the occurrence of the retention mechanisms. As an example, the importance of the gravity force and interaction forces on retention mechanisms are confirmed at the microscale in comparison with others forces involved in retention mechanisms such as the drag force, lift force, cohesive force, buoyancy force, and virtual mass force.
Highlights
Sand destroys oil production equipment, such as pipes and pumps [1]
By having equal densities for the fluid and solid phases, the computational fluid dynamic (CFD)–discrete element method (DEM) model showed that the particle was eventually becoming suspended, which was equivalent to the zero terminal velocity
The problem of drafting–kissing–tumbling of two particles [41] was replicated with the CFD–DEM model to investigate the capability of the model to capture the physics involved in particle–particle interaction
Summary
Sand destroys oil production equipment, such as pipes and pumps [1]. Sand control technology reduces energy costs for the oil and gas industry [2]. Particle-retention mechanisms that occur at filter openings help with sand control [4] and supports sand filtration [5]. Various retention mechanisms under various conditions are explored under particulate flows with low concentrations of sand particles. These conditions are applied through cases without and with porous media on top of the filter opening, various concentrations of particles, the effect of fluid flow, shape of the particles, particle size distribution, the role of the physical forces, as well as the filter opening shape and size. This study aims to offer an insight into the occurrence of the retention mechanisms in slurry flow with heavy oil as the carrier phase [11]. Discrete element method (DEM) model, capable of predicting occurrence of retention mechanisms in slurry flow, as well as a breakdown of the physics involved in the retention mechanisms involved in slurry flow
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