calcium chloride

1. n. [Drilling Fluids]
A highly soluble calcium salt of formula CaCl2 used to make drilling and workover fluids or brines with a density range from 8.33 to 11.6 lbm/gal [1.39 g/cm3] at saturation. CaCl2 can be blended with other brines, including sodium chloride [NaCl], calcium bromide [CaBr2] and zinc bromide [ZnBr2]. Emulsification of CaCl2 brine as the internal phase of oil-base or synthetic-base mud is an important use because the brine provides osmotic wellbore stability while drilling water-sensitive shale zones.