(355a) Interfacial Rheology of Hydrate Formation

Hydrates are crystalline, ice-like structures that arise when water at cold temperatures is brought into contact with lower molecular weight hydrocarbons. These clathrate-class crystals are detrimental to the production and transportation of oils and gas since they solidify to form networks of sludge that can clog piping systems. This paper describes the use of interfacial shear rheology as a means of following the kinetics of hydrate formation. This is accomplished using a brass, double-wall ring interfacial rheometer using a du Nouy ring as a means of dynamically probing the interface at small stains. The protocol consists of first tracking the freezing of the surface of the air/water interface in the absence of a hydrocarbon. Once that occurs, cyclopentane is introduced on top of the water and the temperature is then raised slightly above the freezing point of water. The interfacial shear moduli are then tracked as a function of time to reveal the growth of hydrates at the water/cylcopentane interface. The use of this instrumental platform to monitor the mechanical properties of hydrate interfaces is presented. The efficacy of hydrate-prevention strategies is also described.