In the oil and gas industry, water injection, also known as waterflooding, involves injecting water into an oil reservoir to maintain pressure and sweep oil toward production wells.
This Enhanced Oil Recovery (EOR) method is the most common secondary recovery technique, increasing the amount of oil that can be economically recovered by pushing it to the surface.
Water is pumped from external sources or aquifers through injection wells into the depleted reservoir to displace and lift the oil.