Evaluation of a Novel Water-Immiscible Kinetic Hydrate Inhibitor Formulation

Abstract

The application of low dosage kinetic hydrate inhibitors (KHIs) for hydrate mitigation in hydrocarbon production operations can offer considerable practical benefits and cost savings. However, there are still concerns over KHI usage, particularly with respect to fouling problems in produced water handling/disposal. One possible solution to fouling is KHI polymer removal from produced waters by solvent extraction, with fatty alcohols showing particular promise for this purpose, these having a high affinity for common KHI polymers, but very limited miscibility with water. In this study, it is demonstrated that such solvents can also be used to create novel water-immiscible KHI formulations, with these offering potential for KHI recycling/reuse. The fatty alcohol 1-octanol has been successfully used as carrier solvent for PVCap to produce a KHI, which is immiscible with water, yet shows comparable hydrate inhibition performance to aqueous PVCap. Evaluation of this immiscible KHI using a crystal growth inhibition method shows that it can work well in various systems, including for dry/lean gases, with highly saline waters, and even in the presence of liquid hydrocarbons, despite strong dilution by these.