Zr-Induced Thermostable Polymeric Nanospheres with Double-Cross-Linked Architectures for Oil Recovery

For the purpose of ameliorating the temperature resistance of nanopolymer particles, a kind of hyper-cross-linked polymer, named Zr-AM/NVP/AMPS [main monomer acrylamide (AM), functional monomers N-vinylpyrrolidone (NVP), and 2-acrylamide-2-methylpropanesulfonic acid (AMPS)] with size varying from 100 to 170 nm and special double-cross-linked architectures, were prepared through inverse emulsion copolymerization of organic cross-linking agent N, N-methylene bis acrylamide (MBA), and metal cross-linking agent zirconium acetate (Zr) as a cross-linking system, ammonium persulfate (KPS) as the initiator for the first time. The surface morphology, pore structure, particle size distribution, cross-linking architecture and element distribution of nanoparticles were fully characterized with several means including SEM, TEM, LPSA, BET, FT-IR, 13CNMR, elemental analysis, and long-term thermal stability. The SEM, TEM, LPSA, and BET experimental results indicate that the nanopolymer particle exhibits regular spherical shape and smooth surface, has mesopores ranging from 4.9–7.1 nm with a typical diameter centered (BJH pore size distribution) at ∼5.7 nm. FT-IR, 13CNMR, and elemental analysis experimental results indicate that the monodisperse mesoporous networks nanopolymer particles were cross-linked by AM, AMPS, NVP, MBA, and Zr. Compared to the ordinary AM/NVP/AMPS nanoparticles, significantly enhanced high-temperature thermal stability was found under 150 °C. A core displacement experiment showed how the nanopolymer particles could effectively plug the porous media for water control and oil recovery improvement even after aging at 150 °C for three months. Oil recovery is increased by 13% on the basis of water flooding. Zr-AM/NVP/AMPS nanoparticles with double-cross-linked architectures can be a great help for petroleum engineers to better apply this deep profile control and flooding technology.