Characterization of pH-sensitive polymer microgel transport in porous media for improving oil recovery

We found that the sizes of poly(acrylic acid) microgels in solution were high enough to be retained by rock matrix. To overcome this problem, we varied the mixing period and mixing rate with and without heat, added NaOH followed by HCl, injected the polymer at the transient state, and added a chemical agent, but without any success. However, the microgel particles were not propagating through the cores and they plugged just the front face of the core. Thus, this kind of polymer can successfully improve oil recovery in fractured systems only, which we proved experimentally to be significant.