Title: MAXIMUM DRAG REDUCTION ASYMPTOTE OF POLYMERIC FLUID FLOW IN COILED TUBING
Author(s): Subhash N. Shah, Yunxu Zhou, Mewbourne School of Petroleum and Geological Engineering, Well Construction Technology Center, The University of Oklahoma
Presentation: 2006 ASME International Mechanical Engineering Congress and Exposition
Location: Chicago, IL
Date: November 5-10, 2006
Abstract:
This study experimentally investigates the drag reduction characteristics of the most commonly used polymer fluids in coiled tubing applications. The flow loop employed consists of ½-in. straight and coiled tubing sections. The curvature ratio (a/R where a and R are the radii of the tubing and the reel drum respectively) investigated is from 0.01 to 0.076 which covers the typical curvature ratio range encountered in the oil and gas industry applications. Fluids tested include xanthan gum, guar gum, and HPG (hydroxypropyl guar) at various polymer concentrations. It is found that the drag reduction in coiled tubing is significantly lower than that in straight tubing, probably due to the effect of secondary flow in curved geometry. The onset of drag reduction is also found to be delayed as the curvature ratio was increased. A correlation for the maximum drag reduction (MDR) asymptote in coiled tubing is developed. When the curvature ratio is set to zero, the new correlation reduces to the famous Virk’s MDR asymptote for dilute polymer solutions in straight pipes. A new drag reduction envelope is also proposed for the analysis of drag reduction behavior of polymeric fluids in coiled tubing. Application of the new drag reduction envelope is also discussed.
