Calcium Chloride is used in drilling mud with powder or flakes appearance to to supply Calcium ions. Calcium Chloride is one of the drilling fluids weighting agents. It can adjust the activity of the water phase in invert-emulsion mud.

Advantages of Calcium Chloride usage in drilling mud over other weighting agents, is its low price in formulation of solid-free completion brines.

The maximum density obtainable is 11.6 Ibm/gal (SG 1.68) with the addition of Calcium Bromide. Calcium Chloride and other brine completion fluids, eliminate plugging of producing sands often encountered when perforations are made through drilling mud. These brine fluids, free of solids, eliminate the problem of cracking, solidification and settling of solid materials on packers.

Calcium Chloride is used to control the activity of oil-based mud and work over/completion fluids. It is also an effective means of providing high Chloride ion concentration levels in the aqueous phase of mud for balanced activity mud systems, for maximum shale stability.

CaCl2-containing drilling mud can be used in high pressure formations.

It is much easier to dilute this material in water and has the ability to absorb dust from drilling operations inside the well.