Amine N-Oxide Kinetic Hydrate Inhibitor Polymers for High-Salinity Applications

Abstract

A series of glycidyl amine N-oxide polyethers with cyclic and acyclic amine N-oxide side groups and their block copolymers with poly(propylene) oxide (Mn in the range of 1.8-6.4 kg/mol) have been synthesized and investigated as kinetic hydrate inhibitors (KHIs) using a structure II hydrate-forming gas mixture. Polymers based on cyclic amine N-oxides, containing poly(piperidine glycidyl amine N-oxide) units gave a remarkable KHI performance. The best polymers gave similar KHI performance to commercial poly(N-vinylcaprolactam) (PVCap) at the same concentration of 2500 ppm. In addition, upon heating to 95 °C, the best polymers had no cloud point at 2500 ppm (0.25 wt %), even in 15 wt % sodium chloride solution. Thus, these polymers possess excellent potential for injection into high-salinity-and high-temperature-produced fluids.