An improved Eulerian scheme for calculating proppant transport in a field-scale fracture for slickwater treatment

Abstract

Field-scale proppant transport simulation is vital to the development of unconventional resources. Previous research on proppant transport and distribution has mainly focused on small-scale and experimental-scale proppant simulations, and few studies are related to field-scale proppant deployment. In this paper, through coupling of the slickwater flow, proppant flow, and dynamic crack propagation, an improved Eulerian scheme for calculating proppant transport in a field-scale fracture for slickwater treatment is presented. In the improved Eulerian scheme, the effect of the fracture width on the proppant settling rate and the effect of the increase in the settling bed height on the proppant bed build-up rate are taken into consideration. In addition, a new retardation coefficient is introduced to account for the effect of proppant retardation on the proppant flow. The Eulerian scheme is verified through comparison with published works, including experimental results and simulation results, and sensitivity analysis is conducted. Based on the results of this research, we conclude that the lower viscosity slickwater causes the proppant distribution to become more even, and thus, the proppant bed becomes longer and higher. As the proppant diameter increases, the proppant distribution in the fracture becomes more even, and the fracture area supported by the proppant becomes larger. The optimal initial proppant concentration for obtaining the largest propped fracture area is 0.15–0.25. The greater the density of the slickwater is, the more even the proppant distribution is, and the larger the propped fracture area is.