cloud point glycol

1. n. [Drilling Fluids]
A glycol that is soluble at low temperatures but starts to form micelles (molecular agglomerates), thus becoming cloudy, as the temperature is raised. The temperature at which this phenomenon occurs the cloud point is affected by salinity, being generally lower in more saline fluids. Cloud point glycols are used as shale inhibitors. The purported mechanism is that the glycol clouds out at higher downhole temperatures, coating the surface of clays and preventing hydration.