US 11,668,171 B2
Methodology to increase oil production rates in gravity drainage CO2 gas injection processes
Subhash Ayirala, Dhahran (SA); Zuhair AlYousef, Saihat (SA); Dong Kyu Cha, Dhahran (SA); and Muhammad Almajid, Dhahran (SA)
Assigned to SAUDI ARABIAN OIL COMPANY, Dhahran (SA)
Filed by SAUDI ARABIAN OIL COMPANY, Dhahran (SA)
Filed on Aug. 31, 2021, as Appl. No. 17/463,005.
Prior Publication US 2023/0064753 A1, Mar. 2, 2023
Int. Cl. E21B 43/16 (2006.01); C09K 8/594 (2006.01); E21B 43/22 (2006.01)
CPC E21B 43/164 (2013.01) [C09K 8/594 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for treating hydrocarbons in a reservoir, comprising:
determining a pre-treatment critical gas injection rate for the reservoir after introducing an initial or pre-treatment;
introducing a foaming surfactant solution into an upper portion of a reservoir, where the foaming surfactant solution comprises an aqueous solution and a foaming surfactant;
introducing a foaming gas into the upper portion of a reservoir such that the surfactant solution and the foaming gas intimately intermingle and form barrier foam bubbles in the upper portion of the reservoir;
introducing a super/critical carbon dioxide into the reservoir such that a CO2 cap forms above a foam barrier positioned at an interface between the hydrocarbons to be treated in the reservoir and the CO2 cap,
where the foam barrier comprises aggregated barrier foam bubbles, and where the super/critical carbon dioxide is introduced into the reservoir at an injection rate that is greater than the pre-treatment critical gas injection rate for the reservoir; and
recovering hydrocarbons from a lower portion of the reservoir.