Regulation of geochemical activity of microorganisms in a petroleum reservoir by injection of H2O2 or water-air mixture

• Published in: Microbiology (New York) Vol. 77; no. 3; pp. 324 - 333
• Main Authors: Nazina, T. N., Pavlova, N. K., Ni, Fangtian, Shestakova, N. M., Ivoilov, V. S., Feng, Qingxian, Dongyun, Zhao, Prusakova, T. S., Belyaev, S. S., Ivanov, M. V.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-06-2008
• Subjects: Biomedical and Life Sciences; Experimental Articles; Life Sciences; Medical Microbiology; Microbiology; petroleum reservoir; petroleum oxidation; sulfate reduction; methanogenesis; biosurfactants; MEOR
• ISSN: 0026-2617; 1608-3237
• DOI: 10.1134/S0026261708030120

In the course of pilot trials of biotechnologies for the enhancement of oil recovery in formation waters of the Gangxi bed of the Dagang oil field (China), microbiological processes were investigated. The biotechnologies are based on injection into the petroleum reservoir of different oxygen sources (H
2
O
2
solution or a water-air mixture) with nitrogen and phosphorus salts. The injection of water-air mixture with nitrogen and phosphorus salts resulted in an increase in the number of aerobic and anaerobic organotrophic bacteria, rates of sulfate reduction and methanogenesis in formation water and also the content of CO
2
(from 4.8–12 to 15–23.2%) and methane (from 86–88 to 91.8%) in the gas. The preferential consumption of isotopically light bicarbonate by methanogens resulted in a higher content of the light
12
C in methane; the δ
13
C/CH
4
value changed from −45.1…−48.3 to −50.7…−59.3‰. At the same time, mineral carbonates of the formation water became isotopically heavier; the δ
13
C/Σcarbonates value increased from 3.4…4.0 to 5.4…9.6‰. Growth of hydrocarbon-oxidizing bacteria was accompanied by production of biosurfactants and decreased interfacial tension of formation water. Injection of H
2
O
2
solution resulted in the activation of aerobic processes and in suppression of both sulfate reduction and methanogenesis. Methane content in the gas decreased from 86–88 to 75.7–79.8%, probably due to its consumption by methanotrophs. Due to consumption of isotopically light methane, the residual methane carbon became heavier, with the δ
13
C/CH
4
values from −39.0 to −44.3‰. At the same time, mineral carbonates of the formation water became isotopically considerably lighter; the δ
13
C/Σcarbonates value decreased from 5.4…9.6 to −1.4…2.7‰. The additional amount of oil recovered during the trial of both variants of biotechnological treatment was 3819 t.