Study on Agglomeration and Plugging Behavior of Fine Particles in Reservoir Based on DEM-CFD Coupling

Abstract Given the particularity, significance, and complexity of particle migration behavior in fine silt sand hydrate reservoirs, the agglomeration and plugging behavior of free fine particles are mainly studied. Based on the discrete element method (DEM) and computational fluid dynamics (CFD), the DEM-CFD coupled 3D wellbore sand production numerical model is established and verified. The DEM module divides the reservoir particles into coarse and fine components according to the actual particle size distribution, and assigns adhesive and non-adhesive rolling resistance linear models, respectively. The CFD module uses the finite volume method to solve the incompressible Darcy flow in coarse grids. The results show that the DEM-CFD coupled numerical model established can effectively simulate the phenomenon of fine particle agglomeration during particle migration; Compared with the condition without particle agglomeration, fine particle agglomeration can lead to lower wellbore sand production and more severe pore blockage and permeability loss in the surrounding reservoir; The influences of different production and reservoir parameters such as flow rate, porosity and mud content on the variation of wellbore sand production and reservoir permeability under the condition of fine particle agglomeration is further determined, and relevant production measures and suggestions are put forward. The research results help to clarify the sand production mechanism and characteristics of fine silt sand reservoirs and are expected to provide theoretical and technical support for the efficient and safe development of natural gas hydrate resources in fine silt sand reservoirs.