US 12,264,559 B2
Subsurface sequestration of CO2 in subsurface formations
Simon A. Stewart, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Oct. 10, 2023, as Appl. No. 18/483,825.
Application 18/483,825 is a continuation of application No. 17/838,739, filed on Jun. 13, 2022, granted, now 11,834,933.
Prior Publication US 2024/0035360 A1, Feb. 1, 2024
Int. Cl. E21B 41/00 (2006.01); C09K 8/594 (2006.01)
CPC E21B 41/0064 (2013.01) [C09K 8/594 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of subsurface sequestration of CO2 in a subsurface formation, the method comprising:
producing formation water and hydrocarbons from a first well while concurrently injecting an aqueous CO2 solution into a second well, thereby maintaining a pressure balance within the subsurface formation, wherein
the subsurface formation comprises a first region and a second region, the first region and the second region being fluidly connected,
the second region is at a greater depth than the first region and comprises at least one of the subsurface sequestration locations,
the subsurface formation also comprises the first well located within the first region, and the second well located within the second region, and
the subsurface formation also comprises formation water and hydrocarbons naturally present in the subsurface formation; and
allowing the aqueous CO2 solution to sink as a negatively buoyant fluid below the formation water and the hydrocarbons, and into the one or more subsurface sequestration locations, thereby sequestering the CO2 in the second region of the subsurface formation, wherein
the aqueous CO2 solution comprises an aqueous solution and dissolved CO2, and
the aqueous CO2 solution has a greater density than the formation water and the hydrocarbons, making the aqueous CO2 solution negatively buoyant in the subsurface formation.