CO2 Injection is an example of which overarching EOR method?

CO2 Injection is an example of which overarching EOR method?

• A. Gas injection
• B. Chemical injection
• C. Thermal recovery
• D. Waterflood

Answer: (A)

Gas injection is the broad technique in enhanced oil recovery where a gaseous fluid is injected to push oil toward the production wells and to improve flow. CO2 injection fits this category because CO2 is used as a gas flood to displace oil. At sufficient pressure, CO2 can become miscible with the oil, which allows the gas and oil to mix and lowers interfacial tension, helping to mobilize trapped oil; even when not fully miscible, CO2 can dilute and thin the oil to improve sweep efficiency. It’s not chemical injection, which uses chemicals like surfactants or polymers to alter interfacial properties; it’s not thermal recovery, which relies on heat such as steam to reduce oil viscosity or change reservoir conditions; and it’s not a waterflood, which uses water to physically displace oil. So CO2 injection is an example of gas injection.

Gas injection is the broad technique in enhanced oil recovery where a gaseous fluid is injected to push oil toward the production wells and to improve flow. CO2 injection fits this category because CO2 is used as a gas flood to displace oil. At sufficient pressure, CO2 can become miscible with the oil, which allows the gas and oil to mix and lowers interfacial tension, helping to mobilize trapped oil; even when not fully miscible, CO2 can dilute and thin the oil to improve sweep efficiency.

It’s not chemical injection, which uses chemicals like surfactants or polymers to alter interfacial properties; it’s not thermal recovery, which relies on heat such as steam to reduce oil viscosity or change reservoir conditions; and it’s not a waterflood, which uses water to physically displace oil. So CO2 injection is an example of gas injection.