Toluene depletion in produced oil contributes to souring control in a field subjected to nitrate injection.

Souring in the Medicine Hat Glauconitic C field, which has a low bottom-hole temperature (30 °C), results from the presence of 0.8 mM sulfate in the injection water. Inclusion of 2 mM nitrate to decrease souring results in zones of nitrate-reduction, sulfate-reduction, and methanogenesis along the injection water flow path.

Sulfide remediation by pulsed injection of nitrate into a low temperature Canadian heavy oil reservoir.

Sulfide formation by oil field sulfate-reducing bacteria (SRB) can be diminished by the injection of nitrate, stimulating the growth of nitrate-reducing bacteria (NRB). We monitored the field-wide injection of nitrate into a low temperature (approximately 30 degrees C) oil reservoir in western Canada by determining aqueous concentrations of sulfide, sulfate, nitrate, and nitrite, as well as the activities of NRB in water samples from 3 water plants, 2 injection wells, and 15 production wells over 2 years. The injection water had a low sulfate concentration (approximately 1 mM).