Synergy between nano-bentonite and nonionic surfactant in stabilizing solvent emulsion for enhanced heavy oil recovery
Due to the heavy oil reservoirs with low waterflooded recovery and economically unsuitable for thermal recovery,the mixed aromatic hydrocarbons with good viscosity reduction effect was used as solvents,and the mixed aromatics solvent emulsion flooding system was constructed by the synergistic effect of nano-bentonite and alkylphenol polyoxyethylene ether nonionic surfac-tant.The results show that the solvent emulsion prepared by nano-bentonite and alkylphenol polyoxyethylene ether can be stabilized for more than 30 days.The synergistic mechanism is that alkylphenol polyoxyethylene ether adsorbs on the surface of nano-benton-ite particles through hydrogen bonding to realize partial hydrophobic modification,which promotes its firm adsorption on the oil-wa-ter interface to improve the rigidity of the interfacial film,thus greatly improving the stability of solvent emulsion.Besides,the weak aggregation of nano-bentonite after adsorption of nonionic surfactant can form a dense three-dimensional network structure in continuous aqueous phase,which greatly improves the bulk viscosity and interfacial viscoelasticity of solvent emulsion system,and thus enhancing the mobility control ability of solvent emulsion system.Nano-bentonite enhanced solvent emulsion can improve the recovery of heavy oil by more than 25%.The main oil displacement mechanism is that nano-bentonite strengthens the stability and mobility control of solvent emulsion,and the solvent emulsion can significantly improve the flow ability of heavy oil by virtue of the excellent viscosity reduction,thus greatly improving the recovery of heavy oil by water flooding.
nano-bentonitenonionic surfactantemulsified solventsynergistic mechanismsenhance heavy oil recovery
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