| SiO2/AOS or CTAB/PVA |
0.06 wt %/0.06 wt %/0.15 wt % |
40 °C, 1.0 MPa |
2 g/L of NaCl |
7–10 min |
increased crude oil’s sweep
efficiency
under harsh reservoir conditions; oil has a negative effect on the
stability of foam until PVA polymer was introduced because it decreased
the contact surface of the foam and the oil; in addition to preventing
gas diffusion, the polymer reduced the Gibb’s free energy which
is responsible for creating small bubbles |
in addition to the two layers formed by surfactants
and NPs, the use of polymers also forms a third protective layer;
as a result, the strong capillary forces near the plateau border are
reduced, allowing the film fluid to remain in the lamellae, resulting
in foam stability |
(30) |
| Al2O3/AOS or CTAB/PVA |
0.01 wt %/0.06 wt %/0.15 wt % |
8–11 min |
| SiO2/SDS (EH-9, DTAB)/
HEC |
50000 ppm/0.02 wt %/0.02 wt % |
43, 57, 72 °C, 8.96 MPa |
5 wt % of NaCl |
30 min |
- |
an enhancement in the thermal stability of aqueous CO2 foams at HPHT and an increase in apparent viscosity; as a result
of adding polymer to the SiO2-stabilized CO2 foam system, the spatial SiO2 network and foam stability
were strengthened; also, the morphologic distribution of NPs at the
bubble interface are improved |
(31) |
| SiO2/AOS/– |
1 wt %/3.5 wt %/- |
ambient temperature, 1 MPa |
- |
50 min |
enhanced oil recovery by about 13.8–22.4%; this is due to changes in the
oil/water IFT, emulsification, wettability,
and stability/elasticity of foam films |
reduced oil/water
IFT, increased the life of foam, and enhanced
the adsorption of NPs on the film; the improvement is due to NPB adsorption
at the interface between CO2 and water and the aggregation
of NPB in the foam films |
(22) |
