SILICON NANOPARTICLES FOR EXTRACTION OF CRUDE OIL USING CARBON DIOXIDE AND METHOD FOR EXTRACTION OF CRUDE OIL Russian patent published in 2024 - IPC C09K8/594 E21B43/22 

FIELD: oil, gas and coke-chemical industry.

SUBSTANCE: invention relates to water sol used in CO₂ foam flooding for extraction of crude oil by pumping into oil formation of coastal or offshore oil deposit. Aqueous sol increases foam stability even for a considerable period of time at high temperatures and pressures, and in salt water, thereby increasing the degree of extraction of crude oil. Aqueous sol for increasing the stability of a foam or emulsion in a mixture containing carbon dioxide, water and oil, contains silicon dioxide particles having an average particle diameter of 1 to 100 nm, measured by a dynamic light scattering method, and having surfaces at least partially coated with a silane compound with a hydrolysable group. Silicon dioxide particles serve as a colloidal substance and are dispersed in an aqueous solvent having pH of 1.0 to 6.0, which serves as a dispersion medium. Method for preparing the sol involves mixing an aqueous sol containing silicon dioxide particles with a silane compound having a hydrolysable group, wherein the weight ratio of the silane compound to the silicon dioxide particles is (0.01−2):1 and treating the mixture at pH from 1 to 6 for 0.1 to 20 hours. Method of crude oil production includes a step of pumping sol, water and carbon dioxide alternately or simultaneously into an underground oil formation and a step of extracting oil to the surface from the well.

EFFECT: absence of aggregation of silicon dioxide particles, which ensures foam stability.

16 cl, 13 tbl, 27 dwg