Study of a thermoactive gel forming system based on biopolymer for the water shut-off treatment

The presented article discusses the preparation and investigation of a composition based on the natural polymer gum arabic and the vinyl monomer acrylamide, which undergoes chemical transformation under downhole conditions to form a gel. N,N-methylenebisacrylamide and FeCl3 salt were used as cross-linking agents during the process. The composition is viscoelastic, exhibiting characteristics typical of non-Newtonian fluids and demonstrating the Weissenberg effect. It was determined that the boiling point of the composition is 103.7 °C, and the freezing point is -4.5 °C. Depending on the concentration of the components, gel formation occurring within 43-397 minutes at temperatures between 25-75 °C. The swelling rate of the gels increased rapidly within 3-4 hours, with all water samples showing up to a 300%. It was shown that the swelling of the biopolymer-based gel increased sharply over 1-30 hours and continued to stabilize over the next 160 hours, reaching up to 650%. According to studies in the linear reservoir model, the biopolymer-based composition formed a stable gel at a temperature of 50 °C. This proved that the composition better blocked the waterlogged zones. A study was conducted on the isolation of high-permeability layers with a biopolymer composition in a waterlogged layer model with residual oil in the pores. It was found that it is possible to displace 8% of the residual oil from the low-permeability layer with injected water. The prepared biopolymer-based composition can be used as a plugging material for the isolation of undesirable or formation waters in the oil industry. Keywords: biopolymer; viscosity; gelation time; thermoactive; water shut-off; plugging; residual oil; displacement coefficient.