Modified Fe3O4 nanoparticle used for stabilizing foam flooding for enhanced oil recovery

Nanoparticle stabilized foam flooding is a new rising technology of enhanced oil recovery (EOR) which could be applied to produce more crude oil from low permeability reservoirs, but it is still in lab-scale studies. In this paper, Fe3O4 nanoparticles were selected and grafted 1,2-epoxy dodecane for increasing the hydrophobicity of particles' surface and then characterized by FTIR, TGA and TEM. The samples with four different contact angles (12.7 degrees, 20.6 degrees, 57.5 degrees and 94.3 degrees) were chosen to prepare surface unmodified and modified Fe3O4/sodium dodecyl sulfate/polyacrylamide ((M)Fe3O4/SDS/HPAM) foam dispersion systems and compared their static foam stability. The results showed that the modification on the surface of nanoparticles method could prolong foam half-time of Fe3O4 stabilized foam system. The foam half-time of the system stabilized by the modified Fe(3)O(4 )nanoparticles with the contact angle of 94.3 degrees was 2.36 times higher than that of unmodified ones. The core flooding experiments were conducted with the low permeability core samples ( < 10 mD)saturated with Dagang crude oil at 80 degrees C, 18 MPa, and the results indicated that CO2 foam stabilized by modified Fe3O4 with the contact angle of 94.3 degrees could result in a higher oil recovery rate of 10.64 % OOIP after water flooding. It can be concluded that the modified Fe3O4 nanoparticle stabilizing CO2 foam system could be a promising tertiary oil recovery method for low permeability reservoirs.