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.