A new investigation of polymaleamides as kinetic hydrate inhibitors – Improved performance and compatibility with high salinity brines

Abstract Kinetic hydrate inhibitors (KHIs) have been used for over 25 years to prevent gas hydrate formation in oil and gas production flowlines. The main component in KHI formulations is a water-soluble polymer and most of these polymers are amide-based. A few polymaleamides were investigated as KHIs in the 1990s. Since then, our knowledge of the optimal structural features for KHI polymers has improved. Here we report a more detailed KHI study on this class of polymers, demonstrating significant KHI performance enhancement. KHI experiments were conducted under high pressure with natural gas mixture in steel rocking cells using the slow (1 oC/h) constant cooling test method. The best polymaleamides gave To (av.) values at around 6.1 oC (Ca. ΔT = 14.0 oC) at the concentration of 2500 ppm. In addition, the best polymaleamides were compatible with 15 wt.% (150000 ppm) brines at up to 95 oC.