Chelant is a chemical compound that forms stable, water soluble complexes on reaction with metal ions. A chelant prevents metal ions, such as calcium, magnesium, iron, and manganese, from forming insoluble precipitates with other ions in a solution by binding to the positively charged metal ions. Chelating agents that are usually organic compounds that contain carbon, have a ring-like structure that form at least two bonds with the metal ion allowing the chelant to be excreted.
A chelant is used in a wide variety of applications, including oil well workover, hard water scale removal, corrosion control and water treatment.
Trenchlesspedia Explains Chelant
A chelant is used in the oil and gas drilling industry to dissolve barite deposited by drilling mud used in the process. A chelant also removes insoluble materials in well screen and tubing that don't dissolve in acid. Barite is used in the drilling fluid to increase weight to control formation pressure for efficient and safe drilling operations. However; barite in the drilling mud can cause damage to the formation that may reach into the reservoir. Barite solids left over in the wells can cause plugging of screens and perforated and slotted liners.
Since a chelant is insoluble in water and acid, a chelant is the only effective method to get rid of the deposits.