This paper presents experimental results of the effects of coiled tubing curvature on the drag reduction behavior of polymeric fluids in turbulent flow. The experimental setup consists of a 10-ft section of ½-in. OD straight tubing and four coils of coiled tubing of the same diameter. Fluids investigated included water, guar, hydroxypropyl guar (HPG), and Xanthan fluids at various polymer concentrations. It is found that the coiled tubing curvature could reduce the drag reduction by 10 to 30% as compared with straight tubing, depending on the flow conditions. The curvature of tubing also delays the onset of drag reduction. The percentage drag reduction in coiled tubing may be improved if fluid is pumped at higher rates. The results of the present study were also verified with the previous full-scale experiments and are found to be representative of the drag reduction behavior of similar fluids under the field flow conditions.

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