Polyacrylamide grafted polysaccharide as friction reducer for slickwater fracturing treatment

A series of polysaccharide-graft-polyacrylamide copolymers were prepared via conventional free radical polymerization process, where polysaccharide served as macro-initiators in water-in-oil inverse emulsion polymerization media. The formed polysaccharide-graft-polyacrylamide copolymers were evaluated as friction reducers for slickwater fracturing in fresh water and synthetic seawater. Compared to standard friction reducers based on acrylamide copolymers, the new friction reducer based on polysaccharide-graft-polyacrylamide showed better salt tolerance with well-maintained viscosity in synthetic seawater vs. in fresh water. Additionally, it also provided high friction reduction of 65-70% in friction flow loop studies using synthetic seawater with total dissolved solids (TDS) of over 50,000 mg/L. These properties allow the potential utilization of polysaccharide-graft-polyacrylamide as friction reducer when seawater is used as base fluid for slickwater fracturing treatment.