Study on ammonium-promoted phenol-formaldehyde-based gel for enhanced oil recovery and its seepage characteristics in porous media

The phenol-formaldehyde crosslinker has low reactivity at low temperature, and is not easy to occur crosslinking reaction. In order to solve this problem, a kind of ammonium-promoted phenol-formaldehyde-based gel profile control agent was constructed which has the reactivity at low temperature. The basic formula is 0.30%~0.60%polymer, 0.01%resorcinol, 0.60% phenol-formaldehyde crosslinker and 0.10% ammonium salt. The results showed that the final gelling time was 6 days at 65°C, and the final gelling strength could reach G grade. In response to the problem that the plugging characteristics of ammonium-promoted phenol-formalde-hydebased gel are still unclear, the seepage characteristics of the phenol-formaldehyde-based gel in porous media are revealed by physical simulation of sand-pack. The research shows that the plugging rate of porous media with permeability of 2000 mD reaches 98%, the breakthrough pressure gradient is greater than 1.35 MPa/m.