US 12,331,247 B2
Silica nanoparticles for crude oil recovery using carbon dioxide, and crude oil recovery method
Takashi Hiraoka, Tokyo (JP); Hideharu Yonebayashi, Tokyo (JP); Yoshihiro Miyagawa, Tokyo (JP); Masanobu Sagisaka, Hirosaki (JP); and Masashi Abe, Sodegaura (JP)
Assigned to INPEX CORPORATION, Tokyo (JP); HIROSAKI UNIVERSITY, Hirosaki (JP); and NISSAN CHEMICAL CORPORATION, Tokyo (JP)
Filed by INPEX CORPORATION, Tokyo (JP); HIROSAKI UNIVERSITY, Hirosaki (JP); and NISSAN CHEMICAL CORPORATION, Tokyo (JP)
Filed on Jul. 31, 2023, as Appl. No. 18/228,351.
Application 18/228,351 is a division of application No. 17/780,419, granted, now 11,834,608, previously published as PCT/JP2020/044098, filed on Nov. 26, 2020.
Claims priority of application No. 2019-215612 (JP), filed on Nov. 28, 2019.
Prior Publication US 2023/0374372 A1, Nov. 23, 2023
Int. Cl. C09K 8/594 (2006.01)
CPC C09K 8/594 (2013.01) [C09K 2208/10 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A combination comprising in mixture an aqueous sol, carbon dioxide, and water, the aqueous sol comprising silica particles having an average particle diameter of 1 to 100 nm as measured by dynamic light scattering and having surfaces at least partially coated with a silane compound having a hydrolyzable group, the silica particles being dispersed in an aqueous solvent, the aqueous sol having a pH of 1.0 or more to 6.0 or less,
wherein the surfaces of the silica particles are at least partially coated with the silane compound having the hydrolyzable group by adding the silane compound having the hydrolyzable group to an initial aqueous sol of the silica particles in the aqueous solvent, wherein the initial aqueous sol has a pH of 1.0 or more to 6.0 or less,
wherein the aqueous sol, subjected to a storage test at a pH of 5.0 or more to 8.0 or less at 80° C. for 30 days in an environment containing sodium chloride, calcium chloride, and magnesium chloride as main components and having a total salt concentration of 10,000 to 230,000 ppm such that the silica concentration is 1.0% by mass, exhibits a difference between the average particle diameter as measured by dynamic light scattering after the storage test and the average particle diameter before the storage test of 200 nm or less in the aqueous sol, and
wherein the combination forms, in contact with crude oil, a froth or emulsion, and the froth or the emulsion is stable at a temperature of 30 to 120° C. and a pressure of 70 to 400 atm.