Preparation and properties research of a bifunctional hydrophobic associative polymer drag reduction agent for slick water

Abstract

AbstractIn this study, the bifunctional hydrophobic associative polymer of Acrylamide/2‐Acrylamido‐2‐Methylpropane Sulfonic Acid/Lauryl Methacrylate/N,N‐dodecyl Acrylamide (AALD12) with better salt resistance and shear resistance was synthesized by free‐radical micelle polymerization for use as a drag reduction in shale slip water fracturing. In deionized water, the critical associative concentration (CAC) of AALD12 was 0.23%. AALD12 was determined to be theoretically usable for a shale reservoir within 240°C based on its TG study. Microstructure, viscoelasticity, and shear recovery tests show that the polymer has good drag reduction potential and shear resistance. The reduction rates of the polymer AALD12 and the drag reduction agent RSH‐1 in clear water were 77% and 73% (RSH‐1 is a commonly used emulsion‐type drag reduction agent in the market). At the same salt concentration (K+ and Ca2+, 50,000 ppm) and flow rate (40 L/min), AALD12 can maintain a maximum reduction rate of about 63%. The drag reduction rate of RSH‐1 in K+ and Ca2+ solutions can only be maintained at about 52% and 28%, respectively. In the shear resistance test, AALD12 and RSH‐1 were each subjected to three times of cyclic shear in the test pipe. The drag reduction rate of the polymer AALD12 solution can still reach more than 72%. The drag reduction rate of the RSH‐1 solution is about 56%. The drag reduction agent has good salt resistance and anti‐shear bifunction.