# US 2019/0376374 A1 · Systems and methods for carbonated water flooding of hydrocarbon reservoirs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0376374 A1 - Document ID: US20190376374A1 - Status: Published application - Kind: A1 - Application number: 16/005,147 - Filed: 2018-06-11 - Published: 2019-12-12 - Earliest claimed: 2018-06-11 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Subhash Chandrabose Ayirala; Ali Abdallah Al-Yousef; Sultan Al-Enezi; Ahmed Al-Eidan - Web page: https://patentgrep.com/patent/US20190376374A1 ## CPC - E21B 43/164: {Injecting CO2 or carbonated water (in combination with organic material C09K8/594)} - C09K 8/584: characterised by the use of specific surfactants - C09K 8/588: characterised by the use of specific polymers {(polymeric surfactants C09K8/584)} - C09K 8/594: Compositions used in combination with injected gas {, e.g. CO2 orcarbonated gas}(C09K8/592 takes precedence) - E21B 33/13: Methods or devices for cementing, for plugging holes, crevices or the like - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract The present disclosure relates to the recovery of oil from an underground hydrocarbon reservoir, and more particularly to systems and methods for carbonated water flooding of an underground reservoir for enhanced oil recovery. ## Claims ### Claim 1 A method for carbonated water flooding of an underground hydrocarbon reservoir, the method including a step of introducing a volume of carbonated injection water that is saturated with carbon dioxide into an underground hydrocarbon reservoir via an injection well, where the volume of carbonated injection water is introduced into the injection well at a temperature less than 50° C. and a carbon dioxide pressure greater than 1450 psi, where the carbonated injection water includes one or more salts at a total combined salt concentration of 5,000 to 7,000 ppm. ### Claim 2 (canceled) ### Claim 3 (depends on 1) The method of claim 1, where the one or more salts are selected from the group consisting of a calcium-containing salt, a magnesium-containing salt, a sulfate-containing salt, and combinations thereof. ### Claim 4 (depends on 1) The method of claim 1, where the carbonated injection water includes a combined concentration of calcium and magnesium ions of at least 200 ppm and a concentration of sulfate ions of at least 400 ppm. ### Claim 5 (depends on 1) The method of claim 1, where the carbonated injection water includes a combined concentration of calcium and magnesium ions in a range from 200 to 500 ppm and a concentration of sulfate ions in a range from 400 to 1,000 ppm. ### Claim 6 (depends on 1) The method of claim 1, where the carbonated injection water includes carbon dioxide at a mole fraction of at least 0.001. ### Claim 7 (depends on 1) The method of claim 1, where the carbonated injection water includes carbon dioxide at a mole fraction in a range from 0.005 to 0.05. ### Claim 8 (depends on 1) The method of claim 1, where the volume of carbonated injection water is introduced into the injection well at a temperature greater than 20° C. and a carbon dioxide pressure less than 7250 psi. ### Claim 9 (depends on 1) The method of claim 1, further including a step of maintaining the introduced volume of carbonated injection water in the hydrocarbon reservoir so that carbon dioxide gas is released into the underground hydrocarbon reservoir. ### Claim 10 (depends on 1) The method of claim 1, further including a step of preparing the volume of carbonated injection water in a pressurized and temperature-controlled vessel with an outlet that is in fluid communication with the injection well. ### Claim 11 (depends on 1) The method of claim 1, further including a step of introducing a volume of chase fluid into the underground hydrocarbon reservoir after the step of introducing the volume of carbonated injection water. ### Claim 12 (depends on 11) The method of claim 11, where the chase fluid includes carbon dioxide. ### Claim 13 (depends on 11) The method of claim 11, where the chase fluid includes water, and a total combined salt concentration of the chase fluid is greater than a total dissolved salt concentration of the carbonated injection water. ### Claim 14 (depends on 11) The method of claim 11, where the chase fluid includes polymers, surfactants, or both. ### Claim 15 (depends on 1) The method of claim 1, further including a step of decreasing an internal pressure of the underground hydrocarbon reservoir. ### Claim 16 (depends on 1) The method of claim 1, where the carbonated injection water is introduced at a flow rate in a range from 0.5 to 2 cubic meters per minute. ### Claim 17 (depends on 1) The method of claim 1, where, prior to introducing the volume of carbonated injection water into the underground hydrocarbon reservoir, a total dissolved salt concentration of the volume of carbonated injection water is less than a total dissolved salt concentration of water in the underground hydrocarbon reservoir and a temperature of the volume of carbonated injection water is less than a temperature of the water in the underground hydrocarbon reservoir. ### Claim 18 (depends on 1) The method of claim 1, further including a step of recovering a volume of oil from the underground hydrocarbon reservoir after the step of introducing the volume of carbonated injection water. ### Claim 19 A system for carbonated water flooding of an underground hydrocarbon reservoir including: a pressurized and temperature-controlled vessel that includes a volume of carbonated injection water that is saturated with carbon dioxide, at a temperature less than 50° C. and a carbon dioxide pressure greater than 1450 psi, where the carbonated injection water includes one or more salts at a total combined salt concentration of 7,000 ppm or less, where the vessel includes an outlet; and an injection well which is in fluid communication with the outlet of the vessel and an underground hydrocarbon reservoir. ### Claim 20 (depends on 19) The system of claim 19, where the carbonated injection water is at a temperature greater than 20° C. and a carbon dioxide pressure less than 7250 psi. ### Claim 21 (depends on 19) The system of claim 19, where the carbonated injection water includes the one or more salts at a total combined salt concentration in a range from 5,000 to 7,000 ppm. ### Claim 22 (depends on 19) The system of claim 19, where the one or more salts are selected from the group consisting of a calcium-containing salt, a magnesium-containing salt, a sulfate-containing salt, and combinations thereof. ### Claim 23 (depends on 19) The system of claim 19, where the carbonated injection water includes a combined concentration of calcium and magnesium ions of at least 200 ppm and a concentration of sulfate ions of at least 400 ppm. ### Claim 24 (depends on 19) The system of claim 19, where the carbonated injection water includes a combined concentration of calcium and magnesium ions in a range from 200 to 500 ppm and a concentration of sulfate ions in a range from 400 to 1,000 ppm. ### Claim 25 (depends on 19) The system of claim 19, where the carbonated injection water includes the carbon dioxide at a mole fraction of at least 0.001. ### Claim 26 (depends on 19) The system of claim 19, where the carbonated injection water includes the carbon dioxide at a mole fraction in a range from 0.005 to 0.05.