LAUSR

Abstract Viscous slickwater have been successfully applied as an alternative to conventional ones. However, it is still not clear whether these two types of slickwater show the same friction-reduction characteristics when migrated into pipelines and fractures. In this study, the friction-reduction performances of a conventional friction reducer (FR-800) and a highly viscous friction reducer (HVFR-900) in pipelines and fractures were tested through independently designed pipeline and visual crack modules. The corresponding λ (Darcy friction factor) values were calculated based on the friction pressure drop and used to fit a friction factor calculation model. Finally, the dynamic sand-carrying performance of the two friction reducers were obtained through a visual crack module. The results showed that, as the concentration of two friction reducers increased, the friction-reduction performance of FR-800 gradually weakened in the pipeline, while that of HVFR-900 gradually increased; meanwhile, the performances of the two chemicals varied similarly in the fractures. The λ values of FR-800 and HVFR-900 in the pipe and fractures can be calculated by using equations similar to the power-law D&M formula which is usually applied to fluids, various results mainly induced from the type of friction reducer and its concentration. Additionally, it was noted that the dynamic sand-carrying performance of viscous slickwater at a concentration of 0.60 wt% was significantly better than that of conventional slickwater.