纳米SiO2流体的性能及其渗吸驱油效果评价OA北大核心CSTPCD

On the basis of analyzing the physical properties of reservoir rocks and the ion composition of formation water,the rheological properties,interfacial tension and contact angle of 0.5％nano SiO2,0.5％nano SiO2+0.3％sodium dodecyl sulfate surfactant solu-tion and formation water were evaluated through experiments,and the imbibition oil displacement effect of three different component flu-ids was investigated.The results indicate that the size of nanoparticles in the nano SiO2 fluid is approximately 40 nm.Nano SO2 fluid has the characteristics of swelling plastic fluid,and its interfacial tension with crude oil is 12.05 mN/m,which is about 30％of the interfa-cial tension between formation water and crude oil.Nano SO2 fluid can change the lipophilic rock core to weakly hydrophilic rock core,reducing the contact angle from 126° to 86°.The oil displacement efficiency of nano SiO2 fluid is about 44.67％,which is 13.59％higher than that of formation water.Silicon dioxide nanoparticles and sodium dodecyl sulfate can reduce the interfacial tension of fluid and crude oil to varying degrees,change the wettability of the rock pore throat surface,promote oil-water displacement in the rock,and ultimately improve the imbibition oil displacement efficiency.