2. n. [Drilling Fluids]
Absorption of water by a hygroscopic material such as a clay or polymer. Hydration is the first stage of clay-water (or polymer-water) interaction. When dry bentonite is stirred into water, hydration is observed as swelling.
See: clay-water interaction, colloid, hardness ion, hydrate, hydrophilic, inhibit, inhibitive mud, montmorillonite, prehydrated bentonite, prehydration, seawater mud, soft water, XC polymer