The drag reduction resulting from the addition of small amount of linear macromolecules has found various applications in many areas of the oil & gas industry; including well completion, workover, drilling operations, and hydraulic fracturing. Temperature is among the factors affecting the extent of drag reduction. Other factors include salinity, polymer type and concentration, molecular weight and distribution, solvent chemistry, pH, ionic strength, molecular conformation, flow geometry, and degree of mechanical shearing. Despite the widespread use of brine solutions as base fluids in fracturing the deep hot formations, the effects of temperature on the drag reduction characteristics of polymers have received the least attention. Most studies have considered the ambient temperature conditions. Therefore, the aim of the present study is to experimentally investigate the effect of temperature on the extent of drag reduction of polymers flowing in straight and coiled tubing. The most commonly used anionic polyacrylamides; Nalco ASP-820 is investigated. ASP-820 is a sulfonate containing a partially hydrolyzed polyacrylamide (PHPA). The pre-determined optimum concentration of ASP-820 polymer of 0.07 % (vol.) is used. A small flow loop with straight and coiled tubing sections is employed. To investigate the effect of temperature, tests are conducted with fresh water at 22, 38 and 55°C. It is found that ASP-820 polymer is a quite effective drag reducer in circular pipes. Drag reduction in the range of 30-80% is noticed. Drag reduction is more significant in straight tubing than in coiled tubing. Temperature shows a drastic effect on the drag reduction characteristics and its effect differs from straight to coiled tubing. Correlations to predict drag reduction at elevated temperature are developed. These results are presented and discussed in detail.
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