Coupled model for simulating proppant distribution in extending fracture

Abstract

Proppant distribution has great influence on well performance. It's necessary to investigate the mechanism of proppant distribution in fracturing treatment. This paper presents a new coupled model of fracture propagation with proppant transport. The model considers the coupling of sand settling, proppant bed build-up and wash-out, fluid velocity, and fluid filtration in extending fracture. The finite difference method combined with boundary element method are used to make the model quickly solved. Two different moving mesh systems are used to facilitate the moving boundary. The solutions are validated against published experimental data. The effect of fluid viscosity, injection rate, fluid filtration, injection proppant concentration and particle size on proppant distribution in fracture is studied. According to the study, proppant settling has great influence on the proppant bed balance height and proppant concentration. Fracture length and width decreases with the increase of the fluid leak-off coefficient, increases with the increase of the injection rate. The transport distance of proppant increases with the increasing injection rate, fluid viscosity and injection proppant concentration, and decreases with the increasing particle size. Fluid leak-off has less effect on equilibrium height of proppant bed and proppant migration distance.