LAUSR

Abstract This work presents experimental results on the inhibition performance of kinetic hydrate inhibitors (KHIs) of structure-II hydrates. The studied KHIs, namely derivatives of copolymers of N-vinylcaprolactam (VCap) and alkylimidazolium salts, were synthesized at the Mexican Petroleum Institute with the objective of producing copolymers with higher cloud points than that exhibited by the poly(N-vinylcaprolactam) homopolymer. Three experimental methods were used to evaluate the hydrate inhibition performance of the synthesized copolymers: the capacity to inhibit the formation of tetrahydrofuran (THF) hydrates (under atmospheric pressure and at a temperature of −0.5 °C; i.e., a subcooling for THF hydrates of about 3.4 °C); the capacity to inhibit the formation of natural gas hydrates under high pressure (about 6 MPa) and low temperature conditions (about 1 °C; i.e. a subcooling of 16 °C for the studied natural gas sample); and the determination of the cloud point temperature of the studied copolymers in aqueous systems of varying salinity (under atmospheric pressure and temperatures ranging from 2 to 81 °C). The inhibition performance and the high solubility (in highly saline aqueous systems) of the synthesized copolymers seems to indicate that these compounds can be considered as promising low dosage inhibitors to prevent or delay the formation of hydrates during the production and transport of hydrocarbons.