Hypochlorite (or sodium hypochlorite (NaOCl) also known as bleach), is used in the oil and gas and water well drilling industry. It has the ability to oxidize and degrade polymers used in drilling muds and completion fluids.
It is also used to remove filter cakes, damages relating to drilling mud, mud clean up, and as a biocide in the oil and gas industry.
Trenchlesspedia Explains Hypochlorite
Polymer drilling muds used in the water well drilling industry can be broken down easily using hypochlorite as it is cheap and effective. Chlorine in the form of hypochlorite is supposed to be the easiest way to handle the chemical and is commonly available as calcium and sodium.
For easy handling on the drilling site, it was found that powdered calcium hypochlorite with 35% free chlorine is the best.
To break polymer drilling muds quickly and effectively disinfect the well, a minimum concentration of 1000 mg/l of free chlorine is required. The hypochlorite is mixed with water and introduced into the borehole using the drill rods.