Syntheses of a Hyperbranched Polymer and Its Performance on Enhanced Oil Recovery

Abstract

A hyperbranched carboxylate-type polymer was synthesized through esterification and carboxymethylation, and its performance on enhanced oil recovery was experimentally evaluated. The optimum condition for esterification was 8 h at 120°C, where 3% PTSA as the catalyst and 9:1 mol ratio of the AB2 intermediate and trimethylolpropane were used. The optimum condition for carboxymethylation was 4 h at 80°C. The critical micelle concentration of the hyperbranched polymer was 433.63 mg/L, the Krafft point was 5°C, and the surface tension was lowered to 28 mN/m. In the range of 400–500 mg/L concentration, the adsorption onto the oil sand surface achieved equilibrium, and micellar solubilization reached 600 ml/mol. The interfacial tension can be lowered to a level of 10−2 mN/m by the single use of the hyperbranched polymer, and the value further decreased to a level of 10−3 mN/m while being formulated with sodium dodecylsulfate or NaOH. Oil recovery of water flooding was further enhanced by the single use of a hyperbranched polymer or the combination of hyperbranched polymer/sodium dodecylsulfate. The latter exhibited more prosperous advantages in low-permeability reservoirs.

Overview of Methods for Enhanced Oil Recovery from Conventional and Unconventional Reservoirs

“…With increased values of the water-air factor, varieties of combined technology arise based on a combination of waterflooding with in situ oxidative reactions. In this case, the combustion front, as well as adjacent zones of superheated steam, will cease to exist, and the injected air will enter the saturated steam zone, where it enters exothermic reactions with oil [117].…”