Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics
Abstract Reservoir souring is a widespread phenomenon in reservoirs undergoing seawater injection. Sulfate in the injected seawater promotes the growth of sulfate-reducing bacteria (SRB) and archaea-generating hydrogen sulfide. However, as the reservoir fluid flows from injection well to topside fac...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-01-01
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| Series: | Journal of Petroleum Exploration and Production Technology |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s13202-019-00824-0 |
| _version_ | 1828203230060871680 |
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| author | Mahsan Basafa Kelly Hawboldt |
| author_facet | Mahsan Basafa Kelly Hawboldt |
| author_sort | Mahsan Basafa |
| collection | DOAJ |
| description | Abstract Reservoir souring is a widespread phenomenon in reservoirs undergoing seawater injection. Sulfate in the injected seawater promotes the growth of sulfate-reducing bacteria (SRB) and archaea-generating hydrogen sulfide. However, as the reservoir fluid flows from injection well to topside facilities, reactions involving formation of different sulfur species with intermediate valence states such as elemental sulfur, sulfite, polysulfide ions, and polythionates can occur. A predictive reactive model was developed in this study to investigate the chemical reactivity of sulfur species and their partitioning behavior as a function of temperature, pressure, and pH in a seawater-flooded reservoir. The presence of sulfur species with different oxidation states impacts the amount and partitioning behavior of H2S and, therefore, the extent of reservoir souring. The injected sulfate is reduced to H2S microbially close to the injection well. The generated H2S partitions between phases depending on temperature, pressure, and pH. Without considering chemical reactivity and sulfur speciation, the gas phase under test separator conditions on the surface contains 1080 ppm H2S which is in equilibrium with the oil phase containing 295.7 ppm H2S and water phase with H2S content of 8.8 ppm. These values are higher than those obtained based on reactivity analysis, where sulfur speciation and chemical reactions are included. Under these conditions, the H2S content of the gas, oil, and aqueous phases are 487 ppm, 134 ppm, and 4 ppm, respectively. |
| first_indexed | 2024-04-12T12:02:09Z |
| format | Article |
| id | doaj.art-135353591bf8486daa9c23225dc5e1f0 |
| institution | Directory Open Access Journal |
| issn | 2190-0558 2190-0566 |
| language | English |
| last_indexed | 2024-04-12T12:02:09Z |
| publishDate | 2020-01-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of Petroleum Exploration and Production Technology |
| spelling | doaj.art-135353591bf8486daa9c23225dc5e1f02022-12-22T03:33:49ZengSpringerOpenJournal of Petroleum Exploration and Production Technology2190-05582190-05662020-01-011041603161210.1007/s13202-019-00824-0Sulfur speciation in soured reservoirs: chemical equilibrium and kineticsMahsan Basafa0Kelly Hawboldt1Faculty of Engineering and Applied Science, Memorial University of NewfoundlandFaculty of Engineering and Applied Science, Memorial University of NewfoundlandAbstract Reservoir souring is a widespread phenomenon in reservoirs undergoing seawater injection. Sulfate in the injected seawater promotes the growth of sulfate-reducing bacteria (SRB) and archaea-generating hydrogen sulfide. However, as the reservoir fluid flows from injection well to topside facilities, reactions involving formation of different sulfur species with intermediate valence states such as elemental sulfur, sulfite, polysulfide ions, and polythionates can occur. A predictive reactive model was developed in this study to investigate the chemical reactivity of sulfur species and their partitioning behavior as a function of temperature, pressure, and pH in a seawater-flooded reservoir. The presence of sulfur species with different oxidation states impacts the amount and partitioning behavior of H2S and, therefore, the extent of reservoir souring. The injected sulfate is reduced to H2S microbially close to the injection well. The generated H2S partitions between phases depending on temperature, pressure, and pH. Without considering chemical reactivity and sulfur speciation, the gas phase under test separator conditions on the surface contains 1080 ppm H2S which is in equilibrium with the oil phase containing 295.7 ppm H2S and water phase with H2S content of 8.8 ppm. These values are higher than those obtained based on reactivity analysis, where sulfur speciation and chemical reactions are included. Under these conditions, the H2S content of the gas, oil, and aqueous phases are 487 ppm, 134 ppm, and 4 ppm, respectively.https://doi.org/10.1007/s13202-019-00824-0Chemical reactivitySeawater injectionSulfur speciationReactive model |
| spellingShingle | Mahsan Basafa Kelly Hawboldt Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics Journal of Petroleum Exploration and Production Technology Chemical reactivity Seawater injection Sulfur speciation Reactive model |
| title | Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics |
| title_full | Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics |
| title_fullStr | Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics |
| title_full_unstemmed | Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics |
| title_short | Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics |
| title_sort | sulfur speciation in soured reservoirs chemical equilibrium and kinetics |
| topic | Chemical reactivity Seawater injection Sulfur speciation Reactive model |
| url | https://doi.org/10.1007/s13202-019-00824-0 |
| work_keys_str_mv | AT mahsanbasafa sulfurspeciationinsouredreservoirschemicalequilibriumandkinetics AT kellyhawboldt sulfurspeciationinsouredreservoirschemicalequilibriumandkinetics |