EI Research Report
The Use of Nitrate Treatment in Oilfield Systems to Control Reservoir Souring: A review of Current Status
Over the past 15 years, a method that has emerged to considerably reduce the level of biogenic hydrogen sulfide (H2S) production in oilfield systems is the treatment of injection water with nitrate (NO3−). Nitrate treatment technology is increasingly used for the control of sulfate (SO42−)-reducing microorganisms, and hence the prevention and mitigation of biogenic H2S by oil production and oilfield service companies. However, its success and the effect of NO3− on corrosion processes vary considerably and appear to be specific to operating conditions. For instance, the use of nitrate treatment in seawater injection has not been observed to increase corrosion rates and there is indication that it may even reduce corrosion. However, there is evidence that the application of NO3− in a produced water reinjection (PWRI) system can lead to an increase in both general and localised corrosion.
With that in mind, this review supersedes the first edition, The stimulation of nitrate-reducing bacteria (NRB) in oilfield systems to control sulfate-reducing bacteria (SRB), microbiologically influenced corrosion (MIC) and reservoir souring: An introductory review, 2003, Energy Institute (EI). Currently, nitrate treatment is used on a number of installations in a variety of environmental conditions. Based on the current literature, reports and presentations, as well as the experimental and trial data, this review aims to enhance this publication with information now available, relating to experimental investigation and industry experience.