Underground Injection Control

ECMC regulates Class II underground injection wells.

Class II wells are used only to inject fluids associated with oil and natural gas production. Class II fluids are primarily brines (salt water) that are brought to the surface while producing oil and gas. The US Environmental Protection Agency (EPA) defines injection classes and ECMC follows EPA’s class definitions.

Class II wells are used specifically for enhanced oil recovery through injection of water, gas, or other substances, or as disposal wells injecting oil and gas exploration and production waste. The UIC permit review requires a seismicity review using Colorado Geological Survey maps, the United States Geological Survey earthquake database and area-specific knowledge to assess seismic potential associated with proposed injection.

All UIC wells must pass a Mechanical Integrity Test (“MIT”) after it has been set up in the final injection configuration. The MIT assures that injected fluids are contained by the injection tubing and packer. MITs are required at 5-year intervals for the life of the UIC well. The ECMC calculates a maximum injection volume, and is initially restricted to a one-quarter mile radius. This restriction is intended to constrain the total volume of injected fluids during the life of the injection well.