Lime is used as a source of calcium and alkalinity in both water- and oil-based drilling fluids. Lime, a widely available commercial chemical, is an economical source of calcium (Ca²⁺) and hydroxyl ions (OH^–).

Widely available economical source of calcium and alkalinity

Drilling fluid applications for lime include increasing pH, providing excess lime as an alkalinity buffer, flocculating bentonite muds, removing soluble carbonate (CO₃^2–) ions, controlling corrosion, and activating fatty-acid, oil-based mud additives.

Toxicity and handling

Bioassay information is available upon request. Handle as an industrial chemical, wearing protective equipment and observing the precautions as described on the transportation and safety data sheet.

Avoid exposure and handle only when fully protected. Lime is an alkaline material and can burn eyes, skin, and respiratory tract and may react violently with water or acids.

Lime should be added slowly to the mud system through a properly designed mud hopper. Do not mix lime with other chemicals or through the chemical barrel (due to its limited solubility, it will settle).

Packaging and storage

Lime is usually packaged in 22.7-kg [50-lbm] and 25-kg [55-lbm], multiwall paper sacks; numerous other sack sizes are used.

Store in a dry area away from water and acids. Keep all containers sealed. Once a container is opened, it should be used immediately. Lime is highly reactive and may be corrosive to certain materials.