Document Type : Research Paper
Department of Petroleum Engineering, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
Using a sulfonated polyacrylamide (SPAM) and Cr3+, a new colloidal dispersion gel (CDG) was prepared. The viscosity of the CDG samples in different crosslinker concentrations and brine compositions was measured. The results showed that CDGs approach a Newtonian-like behavior in high crosslinker concentrations and salinities, signifying that they possess more rigid, less flexible particles that can be used to block some of the pore throats of the high-permeability layers. Therefore, three core flood tests were performed and the retention of the polymers and the final RRF values (residual resistance factor) were determined. Although CDGs showed a lower tendency to be adsorbed onto the rocks, they caused drastically higher RRF values (caused higher permeability reductions). Thus, it can be concluded that CDGs are superior compared to normal polymer solutions in modifying the permeability. Moreover, changing the post-flood fluid from brine to distilled water caused the RRF to decrease, hence a weaker effect on the permeability.