Hydrated lime (calcium hydroxide) is a dry powder used to raise pH in various industrial applications, including clear water drilling. Hydrated lime, otherwise known as slack lime, builders lime, or pickling lime, is made from a mixture of quicklime and water.
In clear water drilling, hydrated lime is added to the sump water to increase the pH and provide calcium ions in a process called slacking. In a Gyp-based mud system, hydrated lime is added at a concentration of 1.0 kg/m³ and then used as needed to maintain a pH of 10.0-11.0 in the drilling fluid.
Hydrated lime is used to adjust the alkalinity when bicarbonate/carbonate contamination exists. It is used to maintain the alkalinity of oil-based drilling fluids, enhancing the performance of emulsifiers and offering a degree of corrosion protection.
