Kazakhstan journal for oil & gas industryKazakhstan journal for oil & gas industry2707-42262957-806XKMG Engineering10866010.54859/kjogi108660Research ArticleIncreasing the efficiency of bactericide use when using seawater in a reservoir pressure maintenance systemBidzhievaSalimat Kh.<p>Cand. Sc. (Biology)</p>s.bidzhieva@kmge.kzhttps://orcid.org/0000-0002-7599-114XNurseitovNauruzbek K.n.nurseitov@kmge.kzKalmukhanovaTilektes B.t.kalmukhanova@kmge.kzUtepovMaksat S.m.utepov@kmge.kzBranch of KMG Engineering LLP KazNIPImunaigaz151220235448591407202309112023Copyright © 2023, Bidzhieva S.K., Nurseitov N.K., Kalmukhanova T.B., Utepov M.S.2023<p><strong>Rationale:</strong> Since 2018, at the Uzen oilfield, in order to study and control the microbiological contamination with sulfate-reducing bacteria (hereinafter referred to as SRB) of oilfield environment, full-scale bactericidal treatment and monitoring of the effectiveness of reagent use have been carried out. At the equipped control points, water samples are taken for the content of SRB cells before and after injection of the bactericide.</p> <p><strong>Target:</strong> Reduce the intensity of sulfidogenesis at the oilfield and, as a consequence, the concentration of hydrogen sulfide in the associated gas.</p> <p><strong>Materials and methods:</strong> Since the applied technology of injecting the bactericide in shock dosages did not allow achieving a stable reduction in the concentration of hydrogen sulfide, it was replaced by the technology of constantly injecting the bactericide into seawater at a dosage of 40 mg/l in an experimental mode. This technology showed low efficiency, hydrogen sulfide (H₂S) concentrations varied between 352–379 ppm, and the monthly consumption of the reagent increased by 40%. Based on the obtained data on ineffectiveness, the constant injection of bactericide at MPS-4 was stopped and a new technology for injection of bactericide was proposed, aimed at suppressing not only planktonic, but also adherent forms of SRB.</p> <p><strong>Results:</strong> Results. Injection of the bactericide using the new technology showed significant efficiency, which was assessed by reducing the concentration of hydrogen sulfide in the associated gas by an average of 45% across the oilfield.</p> <p><strong>Conclusion:</strong> The proposed new technology for injecting a bactericide made it possible to effectively suppress the activity of sulfidogenic microorganisms and reduce the level of biogenic hydrogen sulfide in the oilfield.</p>bactericidehydrogen sulfidesulfate-reducing bacteriasulfate reductionbactericidal treatmentбактерицид, күкіртсутексульфатты қалпына келтіретін бактерияларсульфатты қалпына келтірубактерицид айдаубактерицид, сероводородсульфатвосстанавливающие бактериисульфатредукциябактерицидная обработка1.Gieg LM, Jack TR, Foght JM. Biological souring and mitigation in oil reservoirs. Appl Microbiol Biotechnol. 2011;92(4):263–282. doi:10.1007/s00253-011-3542-6.2.Magot M, Ravot G, Campaignolle X, et al. Dethiosulfovibrio peptidovorans gen. nov., sp. nov., a new anaerobic, slightly halophilic, thiosulfate-reducing bacterium from corroding offshore oil wells. Int J Syst Bacteriol. 1997;47(3):818–824. doi:10.1099/00207713-47-3-818.3.Liamleam W, Annachhatre AP. Electron donors for biological sulfate reduction. Biotechnol Adv. 2007;25(5):452–463. doi:10.1016/j.biotechadv.2007.05.002.4.Khatib ZI, Salanitro JR. Reservoir souring: analysis of surveys and experience in sour waterfloods // Society of Petroleum Engineers; 1997 Oct 5–8; San Antonio, Texas. Available from: https://onepetro.org/SPEATCE/proceedings-abstract/97SPE/All-97SPE/SPE-38795-MS/189127.5.Holubnyak YI, Bremer JM, Mibeck BAF, et al. Understanding the souring at Bakken oil reservoirs // Society of Petroleum Engineers; 2011 Apr 11–13; The Woodlands, Texas, USA. Available from: https://onepetro.org/SPEOCC/proceedings-abstract/11OCS/All-11OCS/SPE-141434-MS/151097.6.Muyzer G, Stams AJM. The ecology and biotechnology of sulphate-reducing bacteria. Nat Rev Microbiol. 2008;6:441-454. doi:10.1038/nrmicro1892.7.Sokolova DS, Semenova EM, Grouzdev DS, et al. Sulfidogenic microbial communities of the Uzen high-temperature oil field in Kazakhstan. Microorganisms. 2021;9(9):1818. doi:10.3390/microorganisms 9091818.8.Imanbayev BA, Zhaparov NS, Maksut DM, Utepov MS. Methods of combating biogenic hydrogen sul- fur at the Uzen and Karamandibas oilfield. Kazakhstan journal for oil & gas industry. 2021;4(9):79–92. (In Russ).9.Ezhova AV. Lithology. 3th ed. Tomsk: Tomsk Polytechnic University Press; 2009. (In Russ).10.Pereira GF, Pilz-Junior HL, Corção G. The impact of bacterial diversity on resistance to biocides in oilfields. Sci Rep. 2021;11(1). doi:10.1038/s41598-021-02494-7.11.Mullaev BT, Abitova AZ, Sayenko OB, Turikpenbayev BZ. Uzen field. Problems and solutions. Almaty: Nur-Print; 2016. (In Russ).