What are the types of Class II wells?
Three types of Class II injection wells are associated with oil and natural gas production. • Enhanced Recovery Wells inject brine, water, steam, polymers, or carbon dioxide into oil-bearing formations to recover residual oil and-in some limited applications-natural gas. This is also known as secondary or tertiary recovery. The injected fluid thins (decreases the viscosity) or displaces small amounts of extractable oil and gas, which is then available for recovery. In a typical configuration, a single injection well is surrounded by multiple production wells. Production wells bring oil and gas to the surface; the UIC Program does not regulate production wells. Enhanced recovery wells are the most numerous type of Class II wells, representing as much as 80 percent of all Class II wells. • Disposal Wells inject brines and other fluids associated with the production of oil and natural gas or natural gas storage operations. When oil and gas are produced, brine is also brought to the surfac
