A new CFD approach for proppant transport in unconventional hydraulic fractures

Abstract

For hydraulic fracturing design in unconventional reservoirs, the existing proppant transport models ignore the fluid leak-off effect from the fracture side wall and the effect of fracture roughness. In this paper, a model is proposed using three-dimensional computational fluid dynamics approach with fluid leak-off rate defined along the fracture length and considering the effect of fracture roughness on proppant distribution. Based on the simulation results, it is recommended that neglecting the fracture roughness in the proppant transport model can result in over predicting the proppant bed length and underpredicting the proppant suspension layer by 10–15%. Furthermore, neglecting the fluid leak-off effect can result in under predicting the proppant bed height by 10–50% and over predicting the proppant suspension layer by 10–50%. This study has enhanced the understanding of the proppant-fracturing fluid interaction phenomenon by accounting detailed physics to optimise the hydraulic fracturing design.