Chemical Enhanced Oil Recovery (CEOR) is a method used to extract additional oil from reservoirs after primary and secondary recovery techniques have been exhausted. This process involves injecting chemicals, such as surfactants, polymers, or alkaline agents, into the oil reservoir to improve the flow of oil and reduce its viscosity. The chemicals help to alter the properties of the oil and the surrounding water, making it easier for the oil to move through the rock formations. CEOR can significantly increase the amount of recoverable oil, making it a valuable technique in the oil industry.