低矿化度水-CO2交替驱微分散效应的微观机制OA

Through the contact experiments of the CO2-brine-crude oil system,Fourier-transform infrared spectroscopy tes-ting,component analysis of crude oil,and microfluidic technology,the role and mechanism of CO2 on the formation of micro-dispersion in the crude oil-low salinity water system were investigated.The polar chemical bonds and their source components responsible for micro-dispersion were clarified.And the microscopic mechanism of the micro-dispersion effect in low-salinity water-CO2 alternating flooding was revealed.It is found that the interaction between the polar bonds of C=O and C—H in crude oil and O—H polar bonds in water is the main factor for micro-dispersion formation.With the decrease of salinity of brine,the number of micro-dispersions at the CO2-brine-crude oil system interface rises monotonically.By extracting the light components from the oil through CO2,the polar substances wrapped by the light components are separated and in-creased,which promotes the formation of micro-dispersions.The stronger the ability of crude oil to form micro-dispersion,the greater the viscosity reduction of crude oil saturated with CO2 and the more hydrophilic the interface wettability.In low salinity water,polar reverse micelles capture dissolved water through the diffusion of water in the oil phase,providing more adsorption interfaces for polar compounds.At the interface,the chemical potential of CO2+oil phase increases,and the chemical potential difference between the interfaces of CO2-salt water-crude oil system decreases.