CFD-DEM modelling and analysis of proppant transportation inside tortuous hydraulic fractures

Hydraulic fractures in unconventional gas/oil and tight reservoirs generally have tortuous shapes. This paper presents a numerical study of the proppant transportation and distribution in tortuous hydraulic fractures. This is done by combining computational fluid dynamics (CFD) with discrete element method (DEM). The CFD-DEM model is validated by comparing the numerical results with the experimental measurements of proppant transportation and distributions in single and multiple straight fractures. Via the model, the effect of tortuosity on proppant transportation is studied based on tortuous fractures constructed according to an actual fracture profile. The numerical results show that the packing pattern has a trapezoid shape as the fracture tortuosity varies from 0.6 to 1. It becomes triangular in the tortuosity range of 0-0.4. The horizontal distance and the vertical height of the proppant bed exhibit different trends against fracture tortuosity.