Enhanced oil recovery (EOR) is a set of techniques used to extract more oil from reservoirs after primary and secondary recovery methods have been exhausted. These methods can include injecting substances like water, steam, or chemicals into the reservoir to increase pressure and improve oil flow. EOR can significantly boost the amount of oil that can be recovered, often increasing production by 5% to 15% compared to traditional methods. Techniques such as thermal recovery, gas injection, and chemical flooding are commonly employed to optimize extraction and make the most of existing oil fields.