Use of radiation-induced polymers as friction reducing agents

Drag reduction of fluids containing a water phase, e.g. hydrocarbon-in-water mixture, flowing through a conduit, is reduced by incorporating within the water phase a polymer obtained by radiation-induced polymerization of acrylamide, methacrylamide, acrylic acid, methacrylic acid, alkali metal salts thereof, or mixtures thereof. The polymerization is preferably carried out in 10-60% aqueous monomer solution with gamma radiation. The mixture of monomers, before radiation, preferably contains 25-99% acrylamide and 75-1% sodium acrylate. The polymer preferably shows viscoelastic effects at high concentrations in a solvent. Concentrations of about 1-10,000 ppm of the polymer in the water phase is desired. Examples of fluids useful with this invention include hydrocarbon-in-water and water -in-hydrocarbon slurries, the hydrocarbon is preferably comminuted oil shale or coal, congealed particles of crude oil and/or wax, viscous crude oil, etc