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Visualization of Spontaneous Imbibition of Carbonated Water at Different Permeability and Wettability Conditions
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, IOR 2019 – 20th European Symposium on Improved Oil Recovery, Apr 2019, Volume 2019, p.1 - 16
Abstract
Carbonated Water has earlier been found to improve spontaneous imbibition and thereby improve the oil recovery. These experiments were carried out in micromodels and small core plug samples with minor effects of gravity forces. For the presented study, the objectives have been to study the spontaneous imbibition of carbonated water at different permeability and wettability conditions in a larger 2D cell under the effects of gravity and investigate the process through visualization.
Secondary and tertiary carbonated water spontaneous imbibition experiments were carried out inside a low pressure (10 bar) 2D-cell made using Polyoxymethylene (POM) and Polymethyl methacrylate (PMMA) materials. The diameter of the test area is 170 mm with a 5 mm thickness. A water-soluble pH dye was used to visualize the flow of carbonated water while an oil soluble dye was used to identify the oil flow. Glass beads were used to prepare porous media with different permeability and wettability conditions. The oil production was measured using the visual observations.
Water movement in the porous media was observed to be non-uniform and finger-like pattern was observed near the interface of oil/carbonated water. The finger pattern was more pronounced and faster at higher permeability. With the time the fingers were observed to grow together. Lower spontaneous imbibition rate was observed in lower permeable porous media and the rate of the imbibition was observed increasing with the increase of permeability. Spontaneous imbibition rate was decreasing with the change of wettability from water-wet to mixed-wet.
The oil production was very low from oil-wet porous media. Both from secondary water and carbonated water imbibition, 35%-45% oil production was achieved from water-wet and mixed-wet porous media. In the study of wettability, some fingers were observed only in water-wet porous media. Additional oil production was observed when carbonated water was introduced to water-wet and mixed-wet porous media. Tertiary carbonated water spontaneous imbibition didn't show much difference compared to secondary carbonated water spontaneous imbibition.