| Autor: |
R. Wat, A. Kristoffersen, C.J.T. De Lima, L. Rennan, T. Ramstad |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
Second EAGE Conference on Pre-Salt Reservoir. |
| DOI: |
10.3997/2214-4609.202183030 |
| Popis: |
Summary Equinor has performed an extensive laboratory program using Cretaceous pre-salt carbonate samples from offshore Santos basin, Brazil to investigate oil recovery (EOR/IOR) mechanisms from low salinity water flooding. The program comprises a set of spontaneous imbibition experiments and uses high-resolution micro-CT to image the fluid distributions inside the cores. This way it is possible to observe in detail, the pore scale displacement mechanisms and saturation changes over time. The experiments show that the great salinity contrast between the formation brine and sea water yields an immediate and a gradual increase in water saturation inside the core with enhanced recovery of oil. Furthermore it gives rise to an osmosis process that leads to swelling of trapped formation water. This swelling causes a redistribution of fluids and increases the contact area inside the rock where wettability change can occur resulting further oil production. From these observations, it is concluded that both wettability change and osmosis contribute to enhance oil recovery and are not mutually exclusive. Indeed, the osmosis process can accelerate and enhance the wettability change which can be a powerful recovery method in pre-salt carbonate reservoirs that are naturally oil wet and contain formation water of very high salinity. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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