Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions
Abstract X-ray micro-tomography combined with a high-pressure high-temperature flow apparatus and advanced image analysis techniques were used to image and study fluid distribution, wetting states and oil recovery during low salinity waterflooding (LSW) in a complex carbonate rock at subsurface cond...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2021-07-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-021-94103-w |
| _version_ | 1818992881022533632 |
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| author | Ahmed M. Selem Nicolas Agenet Ying Gao Ali Q. Raeini Martin J. Blunt Branko Bijeljic |
| author_facet | Ahmed M. Selem Nicolas Agenet Ying Gao Ali Q. Raeini Martin J. Blunt Branko Bijeljic |
| author_sort | Ahmed M. Selem |
| collection | DOAJ |
| description | Abstract X-ray micro-tomography combined with a high-pressure high-temperature flow apparatus and advanced image analysis techniques were used to image and study fluid distribution, wetting states and oil recovery during low salinity waterflooding (LSW) in a complex carbonate rock at subsurface conditions. The sample, aged with crude oil, was flooded with low salinity brine with a series of increasing flow rates, eventually recovering 85% of the oil initially in place in the resolved porosity. The pore and throat occupancy analysis revealed a change in fluid distribution in the pore space for different injection rates. Low salinity brine initially invaded large pores, consistent with displacement in an oil-wet rock. However, as more brine was injected, a redistribution of fluids was observed; smaller pores and throats were invaded by brine and the displaced oil moved into larger pore elements. Furthermore, in situ contact angles and curvatures of oil–brine interfaces were measured to characterize wettability changes within the pore space and calculate capillary pressure. Contact angles, mean curvatures and capillary pressures all showed a shift from weakly oil-wet towards a mixed-wet state as more pore volumes of low salinity brine were injected into the sample. Overall, this study establishes a methodology to characterize and quantify wettability changes at the pore scale which appears to be the dominant mechanism for oil recovery by LSW. |
| first_indexed | 2024-12-20T20:33:12Z |
| format | Article |
| id | doaj.art-143c2600ab254915ae9e91107713c43d |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-20T20:33:12Z |
| publishDate | 2021-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-143c2600ab254915ae9e91107713c43d2022-12-21T19:27:18ZengNature PortfolioScientific Reports2045-23222021-07-0111111410.1038/s41598-021-94103-wPore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditionsAhmed M. Selem0Nicolas Agenet1Ying Gao2Ali Q. Raeini3Martin J. Blunt4Branko Bijeljic5Department of Earth Science and Engineering, Imperial College LondonTOTAL E&P, Centre Scientifique et Technique Jean Féger (CSTJF)Department of Earth Science and Engineering, Imperial College LondonDepartment of Earth Science and Engineering, Imperial College LondonDepartment of Earth Science and Engineering, Imperial College LondonDepartment of Earth Science and Engineering, Imperial College LondonAbstract X-ray micro-tomography combined with a high-pressure high-temperature flow apparatus and advanced image analysis techniques were used to image and study fluid distribution, wetting states and oil recovery during low salinity waterflooding (LSW) in a complex carbonate rock at subsurface conditions. The sample, aged with crude oil, was flooded with low salinity brine with a series of increasing flow rates, eventually recovering 85% of the oil initially in place in the resolved porosity. The pore and throat occupancy analysis revealed a change in fluid distribution in the pore space for different injection rates. Low salinity brine initially invaded large pores, consistent with displacement in an oil-wet rock. However, as more brine was injected, a redistribution of fluids was observed; smaller pores and throats were invaded by brine and the displaced oil moved into larger pore elements. Furthermore, in situ contact angles and curvatures of oil–brine interfaces were measured to characterize wettability changes within the pore space and calculate capillary pressure. Contact angles, mean curvatures and capillary pressures all showed a shift from weakly oil-wet towards a mixed-wet state as more pore volumes of low salinity brine were injected into the sample. Overall, this study establishes a methodology to characterize and quantify wettability changes at the pore scale which appears to be the dominant mechanism for oil recovery by LSW.https://doi.org/10.1038/s41598-021-94103-w |
| spellingShingle | Ahmed M. Selem Nicolas Agenet Ying Gao Ali Q. Raeini Martin J. Blunt Branko Bijeljic Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions Scientific Reports |
| title | Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions |
| title_full | Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions |
| title_fullStr | Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions |
| title_full_unstemmed | Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions |
| title_short | Pore-scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions |
| title_sort | pore scale imaging and analysis of low salinity waterflooding in a heterogeneous carbonate rock at reservoir conditions |
| url | https://doi.org/10.1038/s41598-021-94103-w |
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