A Novel Souring Controlling Biocide

Sodium nitroprusside (SNP) and nitrate for metabolic inhibition of sulfate-reducing microbes to control sulfide production.
Tech ID #: 68.5
IP status: US patent granted March 2022.
Combination of SNP and nitrate shows strong synergistic effect on controlling sulfate-reducing microbes.
Can be used at lower concentrations than existing biocides.
Can be used in high temperature reservoirs as well as reservoirs flooded with seawater.


Souring is a common problem in the petroleum industry in reservoirs and in surface processing facilities of oil production operations, under low and high temperature as well as saline or freshwater conditions. Souring results from the growth and activity of sulfate reducing microorganisms, and it must be controlled due to the increased risk to health and safety, deterioration of oil and gas quality, and biocorrosion of pipelines and steel infrastructures. This is commonly achieved through application of biocides. Commonly used biocides have several drawbacks, including environmental concerns from non-target toxicity, and economics of application.

Application of sodium nitroprusside (SNP) in combination with nitrate as a metabolic inhibitor of sulfate reducing microorganisms and as an agent for removal of sulfide has been shown as an effective solution for industrial applications at low or high temperature.



  • To control souring in the petroleum industry in reservoirs and in surface processing facilities of oil production operations.
  • To control souring in pulp and paper or other waste-water processing industries.



  • Safe to humans at low concentrations.
  • More effective at low concentrations compared to other biocides.
  • SNP reacts with and removes sulfide without compromising efficacy.




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