In order to improve the applicability of nano-fluid flooding to reservoir and meet the demand of efficient production,a kind of nanomaterial with dynamic response to temperature is designed.NIPAm/IA/SiO2,a temperature-sensitive nanocomposite,is prepared through grafting N-isopropylacrylamide(NIPAm)and itaconic acid(IA)onto the surface of nano-SiO2.The chemical structure,thermal stability,morphology and particle size of NIPAm/IA/SiO2 are studied by means of infrared spectroscopy,dynamic light strafing and etc.It is indicated by the results that NIPAm/IA/SiO2 has good dispersion performance and thermal stability(initial decomposition temperature of 310℃),and its median particle size is 264 nm.NIPAm/IA/SiO2 shows hydrophilic property when the ambient temperature is lower than the low critical solution temperature(LCST).The wetting effect of temperature-sensitive nanofluid enhances the hydrophilicity of the rock surface and increases the capillary force,therefore NIPAm/IA/SiO2 improves the recovery efficiency mainly through imbibition.NIPAm/IA/SiO2 shows amphiphilicity when the temperature exceeds LCST.Under this condition,the rock surface tends to be neutral wetting,which increases the fluidity of the oil-water two phases,and makes the oil in the pore throat easier be injected into the fluid to displace.
temperature responsivenessnanocompositeenhanced oil recoveryformation temperaturelow critical solution temperature
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