Numerical Study on Particle Transport and Placement Behaviors of Ultralow Density Particles in Fracture-Vuggy Reservoirs

A solid/liquid two-phase flow numerical model based on the computational fluid dynamics-discrete element method (CFD-DEM) model was established to study the transport and settlement law of ultralow-density (ULD) particles during the waterdrive channel adjustment of the Tahe carbonate fractured-vuggy reservoir. The mass, momentum, and turbulence equations of the fluid phase were established in Euler coordinates, whereas the particle motion equations were established based on Newton’s second law. The interaction between the ULD particles was described using a soft sphere model, and the water and particle phases were bidirectionally coupled. Meanwhile, virtual experiments were conducted to calibrate the contact parameters of the particles, and parallel plate experiments were performed to validate the model. Using numerical simulations of particle transport behavior in fractures, the process and characteristics of particle transport and placement in fractures are demonstrated, which can be described by the settlement profile angle and equilibrium gap height. According to parameterized simulations, the change law of the settlement profile angle and equilibrium gap height with different parameters such as particle size, pump displacement, and fracture width are demonstrated, which is helpful for the prediction of migration and accumulation of ULD particles in fracture-vuggy reservoirs.