Drag reduction characteristics in straight and coiled tubing — An experimental study

Going against the flow—A review of non-additive means of drag reduction

“…Despite the clear drag reduction effect of the riblets, it is still far from reaching the excellent performances of polymeric and surfactants DRAs in single and multiphase flow systems. The drag reduction performance reported by some polymeric additives in certain cases is 4-8 times more than the maximum drag reduction achieved by riblets in single phase [3] and multiphase flow systems [49,50]. The basic idea of utilizing riblets is to introduce a permanent and environmentally friendly flow enhancement technique that can replace the use of additives.…”

Effects of salinity and temperature on drag reduction characteristics of polymers in straight circular pipes

“…However, there is still some room where this polymer can be improved to give higher drag reduction and eventually approach Virk's asymptote. Following the same procedure, the optimum concentration for ASP-820 was also found to be 0.07% (Shah et al, 2006). Hence, further analysis and discussion pertains only to 0.07% concentration for both polymeric fluids.…”

“…(1) Fanning friction factor for fresh water containing 0.07% ASP-820 polymer in straight tubing at the same solvent Reynolds number is calculated using the previously developed correlation (Shah et al, 2006) and it is:…”

“…Flow tests at different concentrations of ASP-700 polymer were conducted to determine its optimum concentration. An optimum concentration for ASP-820 was determined earlier as 0.07% (Shah et al, 2006). The optimum concentrations of both polymers were employed in the investigation of the effects of temperature and salinity.…”

An Experimental Study of Flow Behavior of Coiled Tubing Drilling System

“…Shah et al [4] and Shah and Zhou [5] studied influence on drag reduction effect through the polymer concentration, the curvature of CT, and velocity of flow and found that the drag reduction effect is closely relative to turbulent intensity. Willingham and Shah [6] studied the law of frictional pressure losses of four kinds of polymer with different concentration and a kind of drilling mud and arrived at frictional pressure losses correlations which are applicable to the above fluid by fitting the experimental data according to the least squares method.…”