Enhanced Oil Recovery (EOR)

Enhanced oil recovery (EOR) is a set of technologies that increase the amount of oil that can be recovered from a reservoir after primary and secondary recovery methods have been exhausted. EOR methods are used to increase the pressure in the reservoir, reduce the viscosity of the oil, or create a more favorable environment for the oil to flow to the wellbore.

There are a number of different EOR methods that can be used, depending on the specific characteristics of the reservoir. Some of the most common EOR methods include:

* **Waterflooding:** Waterflooding is the injection of water into a reservoir to increase the pressure and drive the oil to the wellbore.
* **Gas injection:** Gas injection is the injection of gas, such as carbon dioxide or nitrogen, into a reservoir to reduce the viscosity of the oil and make it easier to flow.
* **Chemical flooding:** Chemical flooding is the injection of chemicals into a reservoir to improve the wettability of the reservoir rocks and make it easier for the oil to flow.
* **Surfactant flooding:** Surfactant flooding is the injection of surfactants, which are chemicals that reduce the surface tension of water, into a reservoir to improve the wettability of the reservoir rocks and make it easier for the oil to flow.
* **Miscible flooding:** Miscible flooding is the injection of a miscible fluid, such as carbon dioxide or nitrogen, into a reservoir to displace the oil.

EOR methods can be very effective in increasing the amount of oil that can be recovered from a reservoir. However, they can also be expensive and time-consuming to implement. As a result, EOR methods are typically only used in reservoirs that are considered to be economically viable.

The use of EOR methods has increased significantly in recent years as the world's oil reserves have become depleted. In 2019, EOR accounted for approximately 15% of global oil production. It is expected that the use of EOR methods will continue to increase in the future as the world's oil reserves continue to decline.