ABSTRACT
Biocides, also called “bactericides” or “antimicrobials,” are used in oil and gas production primarily to reduce sulde production and microbiologically induced corrosion (MIC) and related biofouling. The aim of a biocide is to kill microorganisms, especially bacteria, or interfere with their activity. Microorganisms in oilelds or in injection water are generally classied by their effect.143,144 Sulfate-reducing bacteria (SRB), denitrifying bacteria (hNRB), slime-forming bacteria, iron-oxidizing bacteria, and miscellaneous organisms such as algae, nitrate-reducing suldeoxidizing bacteria (NR-SOB), yeast and molds, and protozoa can be encountered in bodies of water of oilelds to be treated.1,145 Even carbonate-scale-forming bacteria have been observed in a Middle East eld.2 Bacteria can be found in solution (planktonic), as dispersed colonies or immobile deposits (sessile bacteria plus their waste products). Bacteria can utilize a wide variety of nitrogen, phosphorus, and carbon compounds (such as organic acids) to sustain growth. Nitrogen and phosphorus are usually sufciently present in the formation water to sustain bacterial growth, but injection of organic nitrogen-and phosphorus-containing chemicals can increase the growth potential.
