A new approach to study the friction-reduction characteristics of viscous/conventional slickwater in simulated pipelines and fractures

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 (FR800) and a highly viscous friction reducer (HVFR-900) in pipelines and fractures were tested through independently designed pipeline and visual crack modules. The corresponding lambda (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 lambda 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.