Description
Lime is a high-purity calcium hydroxide having the chemical formula Ca(OH)₂.

Typical Properties
Appearance: White Powder
Specific Gravity: 2.2
pH (%1 solution): 12.4

Features and Benefits
Lime

* is a common and an inexpensive source of soluble calcium for lime-base drilling fluids.
* increases viscosities and gel strength of  (spud mud) for better hole cleaning. This is particularly an important issue in top hole drilling.
* activates fatty acid based primary emulsifiers in oil based drilling fluids by converting them to calcium soap emulsifier in situ.
* reduces corrosion rate by maintaining high pH.
* is very effective in removing bicarbonate and carbonate contaminations from water-base drilling fluids.

The reactions are as follows:

Application
Lime

* is used as a calcium source in lime-base systems.
* is also utilized as flocculant to increase viscosity of spud mud.
* is used to activate primary emulsifier in oil-base drilling fluids.
* is added to treat carbonate and bicarbonate contaminations in water-base drilling fluids.

Limitations
Lime is not suitable for treatment of carbonate contamination in high pH systems due to its low solubility in this environment.

Treatment
In removal of carbonate contamination, treatment levels of Lime are determined depending on the concentration of ions to be removed as follows:

To treat bicarbonates

To treat carbonates

Where F_w is water fraction in the fluid.

In low lime fluid formulation, Lime concentration ranges from 0.3 to 1.0 lb/bbl (0.86 to 2.85 kg/m³). Lime is normally added at concentrations of 5 to 10 lb/bb (14.3 to 28.5 kg/m³) as the primary emulsifier activator in oil-base drilling fluids.

Packaging
Lime is supplied in 25 kg (55 lb) multi-wall paper sacks.