Mechanistic study of microbial control of hydrogen sulfide production in oil reservoirs (original) (raw)
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Applied and Environmental Microbiology, 2021
Sulfate-reducing bacteria (SRB) are one of the main sources of biogenic H 2 S generation in oil reservoirs. Excess H 2 S production in these systems leads to oil biosouring, which causes operational risks, health hazards and can increase the cost of refining crude oil. Nitrate salts are often added to the system to suppress sulfidogenesis. Because SRB populations can persist in biofilms even after nitrate treatment, identifying shifts in the sessile community is crucial for successful mitigation. However, sampling the sessile community is hampered by its inaccessibility. Here we use the results of a long-term (148 days) ex situ experiment to identify particular sessile community members from observations of the sample waste stream. Microbial community structure was determined for 731 samples across twenty bioreactors using 16S rRNA gene sequencing. By associating microbial community structure with specific steps in the mitigation process, we could distinguish between taxa associated with H 2 S production and mitigation. After initiation of nitrate treatment, certain SRB populations increased in the planktonic community during critical time points, indicating the dissociation of SRBs from the biofilm. Predicted relative abundances of the dissimilatory sulfate reduction pathway also increased during the critical time points. Here, by analyzing the planktonic community structure, we describe a general method that uses high-throughput amplicon sequencing, metabolic
Water, Air, & Soil Pollution, 2013
Nitrate addition stimulated sulfide oxidation by increasing the activity of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), decreasing the concentration of dissolved H 2 S in the water phase and, consequently, its release to the atmosphere of a pilot-scale anaerobic bioreactor. The effect of four different concentrations of nitrate (0.12, 0.24, 0.50, and 1.00 mM) was investigated for a period of 3 days in relation to sulfide concentration in two bioreactors set up at Guadalete wastewater treatment plant (Jerez de la Frontera, Spain). Physicochemical variables were measured in water and air, and the activity of bacteria implicated in the sulfur and nitrogen cycles was analyzed in the biofilms and in the water phase of the bioreactors. Biofilms were a net source of sulfide for the water and gas phases (7.22±5.3 μmol s −1) in the absence of nitrate dosing. Addition of nitrate resulted in a quick (within 3 h) decrease of sulfide both in the water and atmospheric phases. Sulfide elimination efficiency in the water phase increased with nitrate concentrations following the Michaelis-Menten kinetics (K s =0.63 mM NO 3 −). The end of nitrate addition resulted in a recovery or increase of initial net sulfide production in about 3 h. Addition of nitrate increased the activity of NR-SOB and decreased the activity of sulfate-reducing bacteria. Results confirmed the role of NR-SOB on hydrogen sulfide consumption coupled with nitrate reduction and sulfate recycling, revealing Sulfurimonas denitrificans and Paracoccus denitrificans as NR-SOB of great importance in this process.
Applied Microbiology and Biotechnology, 2011
Nitrate injection into oil fields is an alternative to biocide addition for controlling sulfide production ('souring') caused by sulfate-reducing bacteria (SRB). This study examined the suitability of several cultivation-dependent and cultivation-independent methods to assess potential microbial activities (sulfidogenesis and nitrate reduction) and the impact of nitrate amendment on oil field microbiota. Microcosms containing produced waters from two Western Canadian oil fields exhibited sulfidogenesis that was inhibited by nitrate amendment. Most probable number (MPN) and fluorescent in situ hybridization (FISH) analyses of uncultivated produced waters showed low cell numbers (≤10 3 MPN/ml) dominated by SRB (>95% relative abundance). MPN analysis also detected nitratereducing sulfide-oxidizing bacteria (NRSOB) and heterotrophic nitrate-reducing bacteria (HNRB) at numbers too low to be detected by FISH or denaturing gradient gel electrophoresis (DGGE). In microcosms containing produced water fortified with sulfate, near-stoichiometric concentrations of sulfide were produced. FISH analyses of the microcosms after 55 days of incubation revealed that Gammaproteobacteria increased from undetectable levels to 5-20% abundance, resulting in a decreased proportion of Deltaproteobacteria (50-60% abundance). DGGE analysis confirmed the presence of Delta-and Gammaproteobacteria and also detected Bacteroidetes. When sulfate-fortified produced waters were amended with nitrate, sulfidogenesis was inhibited and Deltaproteobacteria decreased to levels undetectable by FISH, with a concomitant increase in Gammaproteobacteria from below detection to 50-60% abundance. DGGE analysis of these microcosms yielded sequences of Gamma-and Epsilonproteobacteria related to presumptive HNRB and NRSOB (Halomonas, Marinobacterium, Marinobacter, Pseudomonas and Arcobacter), thus supporting chemical data indicating that nitrate-reducing bacteria out-compete SRB when nitrate is added.
Biochemical Engineering Journal, 2009
Bacteria of the sulphur cycle, in particular sulphate reducing and sulphide oxidizing bacteria, are of immense importance from the industrial and environmental point of views. While biogenic production of H 2 S by sulphate reducing bacteria creates severe processing and environmental problems for the petroleum industry and agriculture sector, when used in a properly designed and controlled bioreactor sulphate reducing bacteria could play an instrumental role in the treatment of acid mine drainage, a major environmental challenge faced by the mining industry. Biooxidation of sulphide and intermediary sulphur compounds carried out by sulphide oxidizing bacteria are crucial in biotreatment of acid mine drainage and in the bioleaching of refractory minerals. Moreover, sulphide oxidizing bacteria are known as major players in the in situ removal of H 2 S from the onshore and offshore oil reservoirs and are used in the ex situ processes for the treatment of sour gas and sulphide laden waters. Owing to the numerous environmental and industrial applications, the bacteria of the sulphur cycle have been subject of numerous studies. The present article aims to provide an overview of the microbiology, biokinetics, current and potential applications of the bacteria of sulphur cycle and the reactions which are carried out by these versatile microorganisms. Special consideration is given to the role of these bacteria in the biotreatment of acid mine drainage, oil reservoir souring and the treatment of H 2 S-containing gaseous and liquid streams.
Biogenic Sulfide Production in Offshore Petroleum Reservoirs Under- Going Waterflooding
2019
Biogenic sulfide production in oilfield systems occurs due to the metabolic activities of sulfate-reducing prokaryotes. These activities of prokaryotes (bacteria and archaea) in production facilities in oilfields leads to unexpected increase in hydrogen sulfide (H2S) concentrations over time in produced fluids from petroleum reservoirs. This widespread phenomenon has proven to have dire consequences, affecting production facilities integrity, personnel safety, environment, the quality and market value of fluids produced from oil reservoirs. Several approaches have been employed over the years to control souring, but the effectiveness of each method differs. This paper reviews the occurrence, consequences, and management of biogenic souring in oilfield reservoirs undergoing waterflooding.
Effect of Nitrates on Sulphide Production by Native Marine Sulphate Reducing Bacteria
2012
Biogenic sulphide production by Sulphate reducing bacteria (SRB) is a major threat because of its toxicity, corrosiveness, plugging oil-reservoir and potential health hazards. Present study reports effect of different concentrations (20, 40 and 60 mM) of three nitrates (NaNO 3 , NH 4 NO 3 and KNO 3 ) on a marine SRBs consortium. Suppression of sulphide production was observed to be concentration and time dependent. Inhibition of sulphide production was noticed after 28 days (at 20 mM) and 14 days (at 40 mM and 60 mM) of incubation. Potassium nitrate resulted faster and greater effectiveness at 40 and 60 mM than other nitrates. At the lowest concentration (20 mM) ammonium nitrate showed better efficiency. After 63 days a maximum of 48.86 % of sulphide inhibition could be achieved by using 60 mM potassium nitrate. Hence, this nitrate can be successfully applied as a efficient, economic and environmentally safe method for rapid and long term inhibition of sulphide production by marine SRBs.
Sulfur Production by Hydrogen Sulfide Biological Removal from Pollutants
Progress in Chemical and Biochemical Research, 2021
Hydrogen sulfide (H2S) is one of the polluting gases that enter the atmosphere during the natural gas processing of coal and furnace oil consumption. One of the best ways to remove H2S is to absorb H2s in the liquid phase and remove it biologically by sulfur bacteria in the liquid phase. This process considers the transfer of H2S and O2 between liquid and gas phases, biological oxidation of H2s to sulfate and elemental sulfur, and chemical oxidation to thiosulfate in the liquid phase. Due to the presence of sulfur bacteria in natural sulfur sources, the sulfur sources of sewage of Shahid Tondgooyan Oil Refining Co. in Tehran, Iran, and Mahallat Hot Spring in Iran, which contain sulfur compounds, were sampled in this study and were transferred to the laboratory for examination. Thiobacillusthioparus – one of the significant bacteria consuming sulfur compounds – was evaluated as a control sample. Further, the performance of bacteria in different culture conditions (carbon source and aeration conditions) was evaluated, and suitable conditions for their growth were determined. Sodium sulfide was used to create the sulfide medium. Next, sulfide consumption was evaluated by bacteria, and appropriate bacteria were selected. Finally, the production of sulfur during the process was evaluated using the ANOVA data analysis method. Then, the optimal points for sulfur production were predicted using the Response Surface Methodology (RSM).
FEMS Microbiology Ecology, 2000
The emission of hydrogen sulfide into the atmosphere of sewer systems induces the biological production of sulfuric acid, causing severe concrete corrosion. As a possible preventive solution, a microbial consortium of nitrate-reducing, sulfideoxidizing bacteria (NR-SOB) was enriched in a continuously stirred tank reactor in order to develop a biological technique for the removal of dissolved sulfide. The consortium, dominated by Arcobacter sp., was capable of removing 99% of sulfide. Stable isotope fractioning of the sulfide indicated that the oxidation was a biological process. The capacity of the NR-SOB consortium for rapid removal of sulfide was demonstrated by using it as an inoculum in synthetic and real sewage. Removal rates up to 52 mg sulfide-S g VSS À1 h À1 were achieved, to our knowledge the highest removal rate reported so far for freshwater species in the absence of molecular oxygen. Further long-term incubation experiments revealed the capacity of the bacteria to oxidize sulfide without the presence of nitrate, suggesting that an oxidized redox reserve is present in the culture.