Title: Effects of Solids Loading on Drag Reduction in Polymeric Drilling Fluids Through Straight and Coiled Tubing
Author(s): S.N. Shah and M. Tareen, The University of Oklahoma, and D. Clark, Baker Hughes INTEQ
Journal: Journal of Canadian Petroleum Technology, Volume 41, No. 5, Page 63
Abstract: An experimental study has been conducted to evaluate the effects of solids on the drag reduction characteristics of polymeric drilling fluids, loaded with solids, through straight and coiled tubing. Polymers investigated were PHPA and XCD. These polymers were dissolved in brines which were prepared by mixing potassium chloride (KCl) and sodium formate (Na-Formate) in water. Various concentrations of Polysaccharide gum (XCD) and Partially Hydrolyzed Polyacrylamide (PHPA) polymers were dissolved in the KCl and Na-Formate solutions. These fluids were pumped through straight pies. Based on the results it was established that PHPA/KCl solution exhibited better drag reduction than PHPA/Na-formate, XCD/KCl, and XCD/Na-formate solutions in straight pipes. Thus PHPA/KCl solution was selected for further study.
This polymer solution was loaded with barite and bentonite to simulate solid cuttings. The fluid system was pumped through different size coiled tubing and straight pipes. Correlation in terms of Fanning friction factor and generalized Reynolds number was developed and percentage drag reduction was calculated. It was observed that when clear polymeric solutions were loaded with solids, drag increases drastically. Finally, the effect of curvature on the flow of solids laden fluids was studied. It was observed that DP in coiled tubing was almost twice as compared to DP in straight tubing for solids laden polymeric fluids under investigation.
