Evaluating the Transport Performance of Novel--Shaped Proppant in Slickwater Fracturing with the Multiscale Modeling Framework

Recently, novel--shaped proppant, such as rod--shaped and x--shaped proppant, has been gradually used in hydraulic fracturing systems, which challenges the validity of previous transport laws for conventional spherical proppant. In this work, a multiscale modeling framework is proposed to solve this issue. We start from constructing particle--scalelaws, including proppant settling, phase--slip, and effective slurry viscosity, based on a refined particle--resolved direct numerical simulation method, that is, the immersed boundary--computational fluid dynamics--discrete element method (IB--CFD--DEM). With this refined simulation method, particle--scale flow details are fully resolved, and accurate particle--scale laws can be reconstructed for novel--shaped proppant. These sub--scale laws are then applied to a field--scale simulation method, that is, the multiphase particle--in--cell (MP--PIC) method. Based on the proposed framework, transport performance of various types of proppant are investigated. Several numerical experiments demonstrate that proppant transport performance can be enhanced by 19 and 15% with x--shaped and rod--shaped proppant, respectively, compared to conventional spherical proppant under 5% inlet proppant concentration and enhanced by 16 and 10%, respectively, under 20% inlet proppant concentration. Moreover, related complicated flow mechanisms at different scales, such as the hindered effect and viscous gravity current effect, are fully discussed, which deepens our understanding of proppant transport and proppant placement.