Enhanced oil recovery (EOR) is an extraction technique used when crude oil can no longer be obtained via traditional methods. EOR works by increasing the flow of oil using water, gas, or chemical injection.
Key fact: EOR techniques extract 30-60% more of a reservoir’s oil, compared 20-40% for primary and secondary recovery techniques
There are three primary techniques used in enhanced oil recovery, the first being thermal recovery. This is when steam is injected into an oil reserve, heating up the crude oil and allowing it to flow more effectively.
Gas injection is another EOR technique that uses natural gas, nitrogen, or carbon dioxide (CO2). Gas injection can achieve two things: it can expand, forcing the oil into a nearby wellbore, or it can improve the oil’s flow rate by dissolving in it and making it less viscous.
EOR also includes chemical injection, a process that uses polymers, surfactants, or other secondary chemical solutions to improve the flow rate of the crude oil.
Key fact: Thermal recovery accounts for over 40% of US EOR production, while gas injection accounts for 60%, and chemical injection only around 1%
Benefits
Maximises oil recovery
Extends life of oil field
Increases recovery factor
