Combination of nano-bentonite stabilized foam and ultra-low IFT surfactant additives assisted steam injection to enhanced heavy oil recovery

Abstract

This study presents an experimental investigation of combination of nano-bentonite stabilized foam and surfactant additives with ultra-low interfacial tension (IFT) to enhance thermal recovery of heavy oil by steam injection. The foam stability results showed that the nano-bentonite can form a three-dimensional network structure to increase the viscosity and thickness of the liquid film, and thus significantly improving the foam stability at high temperature. The foam resistance factor determination demonstrated that the nano-bentonite stabilized foam has good selective plugging ability of reducing the mobility of steam to inhibit the steam channeling. The surfactant additives prepared by the composite system of sodium dodecyl benzene sulfonate and sodium nonylphenol polyoxyethylene ether sulfonate can achieve synergistic effect of high interfacial activity and high-temperature resistance, which can reduce the oil–water interfacial tension to ultra-low level at high temperature. The heterogeneous sandpack flooding results indicated that the nano-bentonite stabilized foam can effectively block the steam channels to improve the sweep efficiency of steam injection and the ultra-low IFT surfactant additives can greatly increase the microscopic oil displacement efficiency. And thus the combination of nano-bentonite stabilized foam and the ultra-low IFT surfactant additives can significantly enhance thermal oil recovery of steam injection in heavy oil reservoirs.