Table 4 Techniques increasing trapping number.
From: A comprehensive review of viscoelastic polymer flooding in sandstone and carbonate rocks
No | Methods | Comments |
|---|---|---|
1 | An increment in displacing fluid viscosity | It can be achieved by adding polymers to the injected fluid |
2 | A decrease in interfacial tension (IFT) between displaced and displacing fluids | Surfactants or alkaline flooding might reduce IFT between oleic and aqueous phases from about 30 to 10–4–10–3 mN m−1 |
3 | An increase in the displacing fluid velocity, and correspondingly in the injection pressure | It is essential to consider a formation fracture pressure while incrementing the injection rate to avoid excessive fracturing |
4 | A reduction in IFT and increment in viscosity simultaneously | This task can be attained by utilizing viscoelastic surfactants or surfactant-polymer (SP) flood |
5 | A wettability alteration towards neutral wettability (\(\theta \to {90}^{0}\)) | Can be achieved by using surfactants or adjusting the injection water chemistry |
6 | Enhancing the contribution of gravity forces | Increasing the density difference between the phases and choosing an efficient displacement trajectory |
