Biocides are essential in oilfield operations to safeguard stimulation or drilling fluids from bacterial contamination and to prevent bacterial invasion into the reservoir. Bacteria can degrade the polymers used in stimulation fluids, reducing their viscosity and friction-reducing abilities. Contamination of reservoirs by bacteria introduced through stimulation fluids can lead to souring. Glutaraldehyde is effective against sulfate-reducing bacteria and provides long-term protection, while quaternary ammonium-based biocides offer rapid elimination but have a shorter lifespan. Sunita provides reliable Biocides for drilling and stimulation, including Glutaraldehyde, DDAC (didecyl dimethyl ammonium chloride), and blends of Glutaraldehyde with quaternary ammonium-based compounds.