Unusual Self-Preservation of Methane Hydrate in Oil Suspensions

The effect of self-preservation of methane hydrate particles with a characteristic size of a few tens of micrometers was found in suspensions of the hydrate in four crude oils. For example, an ice-hydrate suspension in one of the oils at atmospheric pressure and a temperature of -20 degrees C loses only 4% of its gas in 5 h. No self-preservation occurs in suspensions of the hydrate in decane with similarly sized hydrate particles. We consider that the observed self-preservation of such small particles is mainly due to the formation of insulating ice shell on the surface of the hydrate particles. Our results show that the adsorbed medium influences the self-preservation of gas hydrates and allows for this phenomenon to be managed.