Characterization and inhibition of hydrogen sulfide-producing bacteria from petroleum reservoirs subjected to alkali-surfactant-polymer flooding.

Alkali-surfactant-polymer (ASP) flooding is an emerging and promising oil recovery technique. However, the methods for preventing hydrogen sulfide-producing bacteria (SPB), main culprits to microbial souring, in such alkali reservoirs remains unknown. Here, four alkaline-tolerant SPB exhibiting versatile sulfur metabolism were identified. Representative strains DS3, DS5, DS8, and DS23 were associated with Sulfurospirillum alkalitolerans, Desulfonatronovibrio hydrogenovorans, Desulfobotulus sapovorans, and Desulfovibrio alkalitolerans, respectively. Pure culture experiments showed nitrite exerted partial inhibitory effects since DS3 preferred nitrite as an electron acceptor. And nitrate inhibition was feeble, as nitrate was dissimilated to ammonium by DS3 and DS5, and DS8 preferentially utilized sulfate compared with nitrate, and DS23 ignored nitrate respiration. Glutaraldehyde effectively prevented the production of H2S in pure culture and microcosmic simulation system, demonstrating its practical application potential in alkali reservoirs. This study enhances the understanding on physiological characteristics of SPB and bridges the gap in souring management in high alkaline ASP-flooded reservoirs.