关键词: 氟碳纳米液, 　接触角, 　可注入性, 　自发渗吸, 　岩心驱替

Abstract: Non⁃ionic surfactants, fluorinated cationic surfactants, and fluorocarbon polymers have been evaluated for their ability to alter wettability and injectivity in tight sandstone reservoirs through contact angle tests and injectability tests. The results showed that, compared with other chemical agents, the fluorocarbon polymer CRS⁃850 had better gas wetting inversion effect, and the contact angle of the core surface increases from 45.6° to 92.1°; the self⁃absorption of salt water before wettability changing was 0.360 8 g, the self⁃absorption after treatment dropped to 0.020 6 g, the core self⁃aspiration decreased by 98.85%, and the max self⁃suction rate decreased from 0.053 g/min to 0.002 g/min. The wet reversal agent increased the liquid⁃phase percolation capacity of the coreand the gas⁃driving permeation rate significantly, and the recovery effect of core gas drive permeability is remarkable, which increases by 501.69% to 673.91% on the basis of the gas flooding brine, indicating that the gas⁃wetting reverser has beneficial to remove liquid⁃phase damage in tight sandstone reservoirs.

Key words: Fluorocarbon nano?fluid, Contact angle, Injectability, Spontaneous imbibition, Core flooding