Bleach

Other Names: Sodium Hypochlorite (NaOCl)
Basic Properties: Biocide, Oxidizer, Bacteria and Sulfide Control Agent
As a biocide, bleach is used in drilling fluids to control bacterial growth, particularly sulfate-reducing bacteria (SRB), which can lead to microbial-induced corrosion and reservoir souring. By eliminating bacteria, bleach helps maintain the integrity of the drilling fluid and prevents unwanted biological activity that could compromise wellbore stability.
As an oxidizer, sodium hypochlorite effectively breaks down hydrogen sulfide (H_S), a toxic and corrosive gas that can be encountered in drilling operations. By neutralizing H_S, bleach helps reduce the risks associated with sulfide stress cracking (SSC) and improves worker safety.
Bleach is also used to remove biofilms and organic contaminants from drilling equipment and water-based mud systems, ensuring clean and efficient operations. However, it must be used carefully to avoid adverse reactions with other drilling additives, especially polymers and corrosion inhibitors, which may degrade in its presence.
pH: Bleach typically has a highly alkaline pH range of 11 ? 13, which can impact drilling fluid properties and may require pH adjustments when added to the system.