Plugging and Improving Oil Recovery Performance of Polyacrylamide Nanogel in Porous Media

The heterogeneity of a reservoir is always a problem during oil production because injection fluids preferentially flow through higher permeability zones. Hydrogel has been used in petroleum industry by plugging high permeability zone to solve the problem in reservoirs. This work investigated the flow behavior of polyacrylamide based nanogel in porous media, which included injectivity, plugging performance and oil recovery improvement. Two factors were controlled in this work: crosslinking density of nanogel and permeability of porous media. Among the nanogels synthesized by four different crosslinker concentrations, swollen particles have a larger size with lower crosslinker concentration. Meanwhile, within a same permeability range, there were higher plugging efficiency and oil recovery improvement with lower crosslinker concentration. Nanogel has a less plugging efficiency but a better oil recovery improvement in lower permeability porous media