Nitrate for Corrosion, Souring Control, and Improved Oil Production

Abstract

Nitrate for Corrosion, Souring Control, and Improved Oil Production

Nitrate salts are relatively cheap, easy to handle and environmentally friendly. They have historically been used to control sulphate-reducing bacteria (SRB) problems in the municipal waste-water industry and are now becoming widely used in oil field systems. Nitrate acts via numerous mechanisms, which are discussed, to reduce the population of SRB in a system. SRB are responsible for microbiologically influenced corrosion (MIC) and souring of reservoirs by the sulphide by-product, which they excrete. Evidence is presented to show that nitrate can reduce corrosion and souring by SRB in the laboratory and also in the field. In addition, nitrate can also stimulate useful bacteria, which can prevent the return of SRB and also improve residual oil recovery from reservoirs.