Experimental Study On Statics And Rheology Of Nanoparticle-stabilized Supercritical CO₂ Foam

With the carbon peak and the goal of carbon neutrality being put forward,how to effectively reduce the anthropogenic emission of carbon dioxide and improve the recycling of carbon dioxide has become the focus of researchers all over the world.Among them,the development of CCUS-EOR project has become an important way to achieve the goal of carbon dioxide recovery and storage.Carbon dioxide foam flooding is widely used in major oil fields all over the world due to its good effect on enhancing oil recovery,wide application range,and high economy.In this paper,the statics and rheology of nanoparticle-stabilized carbon dioxide foam under high temperature and high pressure are studied,and the effects of surfactant concentration,nanoparticle concentration,temperature,pressure,oil concentration,and salt concentration on the development of carbon dioxide foam are analyzed.foamability and stability.Then,according to the experimental results of CO₂foam statics,the influence of the rheological properties of CO₂foam under high pressure was studied.turn out:The phase state of CO₂has a great influence on the static properties of the foam.When it is close to the supercritical point,the foamability and stability of the CO₂foam are very poor,and when it is far away from the supercritical point,the static properties of the CO₂foam are very good.Among the investigated factors,the order of influence on the foamability of CO₂foam is temperature,pressure,surfactant concentration,nanoparticle concentration,salinity,and oil concentration,and the order of influence on CO₂foam stability is from large to small is temperature,nanoparticle concentration,oil concentration,pressure,salinity,surfactant concentration.Through range analysis,we screened out the best foam performance combination of 0.4wt%AOS+0.15wt%Si O₂.Based on the statics study,through the flow of the foam fluid in the transparent quartz tube,the rheological index and nanoparticle stability of the supercritical CO₂foam in the presence of high pressure CO₂phase,oil,and salt at 3.5MPa and 8MPa,respectively,were investigated.Effect of particle-stabilized foam on apparent viscosity.It is found that the CO₂foam fluid has a critical foam quality under the pressure of 3.5MPa and 20℃.The foam rheology varies from shear thickening to shear thinning,with a maximum apparent viscosity of 29 m Pa·s.On the other hand,the nanoparticle-stabilized supercritical CO₂foams exhibited general shear-thickening behavior in the study,with a maximum apparent viscosity as high as 97 m Pa·s.The presence of oil can significantly increase the apparent viscosity of nanoparticle-stabilized supercritical CO₂foams up to 209 m Pa·s.In contrast,the presence of salt in the surfactant solution reduces the apparent viscosity of the foam,which is lower at 77 m Pa·s.