Key takeaways: 1) Primary drainage or primary migration is the movement of oil (non wetting) inside the reservoir rocks moving the initially present water into smaller pores or corner of the pores. After a while, oil due to its contact with the rock becomes wetting in these regions. 2) Injection of water is in piston like manner, where it fills middle of the pore leading to layer of oil formed between middle water and water at corners. This layer becomes smaller and smaller as more water is injected. 3) Mixed wettability involves both snap off (smaller pores) and percolation (larger pores) processes.
Many thanks for this summary. Point 1 is correct, with the caveat that the wettability change depends on the oil, rock and brine as well as the temperature and pressure: in some cases the rock becomes oil-wet, in others not. Moreover, we can see a mix of water-wet and oil-wet pores in a single sample - this is mixed-wettability. Point 2 is correct in oil-wet pores. Point 3 requires some clarification. In a mixed-wet medium, the water-wet pores and throats fill first (the throats by snap-off) in a percolation-like process. Then oil-wet pores are filled from the already water-occupied regions of the pore space. This is no longer invasion percolation as the water need not be connected through the centre of the pore space to the inlet. Overall displacement in a mixed-wet medium is best thought of as a percolation (not invasion percolation) process.
If we want to injecting low salt water in transition oil water zone or in water invaded zon when there reservoir is carbonates,, the wettability help me to imbibe and extract the oil from the matrix in this zone
Very nice and useful video, thanks again dr Blunt
Key takeaways:
1) Primary drainage or primary migration is the movement of oil (non wetting) inside the reservoir rocks moving the initially present water into smaller pores or corner of the pores. After a while, oil due to its contact with the rock becomes wetting in these regions.
2) Injection of water is in piston like manner, where it fills middle of the pore leading to layer of oil formed between middle water and water at corners. This layer becomes smaller and smaller as more water is injected.
3) Mixed wettability involves both snap off (smaller pores) and percolation (larger pores) processes.
Many thanks for this summary. Point 1 is correct, with the caveat that the wettability change depends on the oil, rock and brine as well as the temperature and pressure: in some cases the rock becomes oil-wet, in others not. Moreover, we can see a mix of water-wet and oil-wet pores in a single sample - this is mixed-wettability.
Point 2 is correct in oil-wet pores.
Point 3 requires some clarification. In a mixed-wet medium, the water-wet pores and throats fill first (the throats by snap-off) in a percolation-like process. Then oil-wet pores are filled from the already water-occupied regions of the pore space. This is no longer invasion percolation as the water need not be connected through the centre of the pore space to the inlet. Overall displacement in a mixed-wet medium is best thought of as a percolation (not invasion percolation) process.
If we want to injecting low salt water in transition oil water zone or in water invaded zon when there reservoir is carbonates,, the wettability help me to imbibe and extract the oil from the matrix in this zone
Yes this can happen if the matrix has water-wet or mixed-wet characteristics.
I have questions can i take your user on telegram?
You can contact me by email at m.blunt@imperial.ac.uk