Osmosis as Mechanism for Low-Salinity Enhanced Oil Recovery
| Autor: | Karen Melhuus, Kristian Sandengen, Leif Olav Josang, Anders Kristoffersen |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Low salinity
020209 energy Environmental engineering Energy Engineering and Power Technology 02 engineering and technology Water flooding Geotechnical Engineering and Engineering Geology Osmosis 020401 chemical engineering 0202 electrical engineering electronic engineering information engineering Environmental science Enhanced oil recovery 0204 chemical engineering Mechanism (sociology) |
| Zdroj: | SPE Journal. 21:1227-1235 |
| ISSN: | 1930-0220 1086-055X |
| Popis: | SummaryWe believe that osmosis has been overlooked as a possible mechanism for observed low-salinity enhanced-oil-recovery (EOR) effects. Osmosis can occur in an oil/water/rock system when injecting low-salinity water, because the system is full of an excellent semipermeable membrane—the oil itself.In the present work, water transport through oil films was visualized both in 2D micromodels and in sandstone cores imaged in a microcomputed tomography (CT). After treating these model systems with hexamethyldisilazane (HMDS) to render them more oil-wet, water became discontinuous, and it was possible to establish osmotic gradients. Either expansion or contraction of the connate water was observed, depending on the direction of the imposed salinity gradient.Because osmosis could be the underlying mechanism for low-salinity EOR, two changes in research strategy are proposed: Most importantly, the use of spontaneous-imbibition tests as evidence for wettability alteration in low-salinity water should be critically reinvestigated. This is because observed production could have stemmed from “osmotic expansion” of the connate water rather than wettability change. Second, much research focus should be shifted from sandstone reservoirs to fractured oil-wet carbonates. Osmosis potentially yields larger responses for the latter reservoir type, whereas from a mechanistic perspective the reason behind low-salinity EOR functioning in both sandstones and carbonates deserves further attention. |
| Databáze: | OpenAIRE |
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