Bell Creek

The Bell Creek Integrated CO₂-EOR and Storage Project is a commercial-scale enhanced oil recovery demonstration conducted by Denbury Resources in southeastern Montana as part of the Plains CO₂ Reduction (PCOR) Partnership Phase III program. The project targets the Lower Cretaceous Muddy Formation sandstone, a mature oil reservoir where anthropogenic CO₂ is injected using water-alternating-gas (WAG) techniques to improve oil recovery while simultaneously storing CO₂ in the subsurface. The reservoir is overlain by the Mowry Formation shale, with additional thick shale sequences providing multiple sealing layers that support long-term containment. Development occurred in phased areas across the field, using standard 40-acre five-spot injection patterns and recycling produced CO₂ for reinjection. CO₂ injection began in May 2013, and by mid-2018 nearly 6 million tonnes of CO₂ had been injected, with an estimated long-term storage potential exceeding 12 million tonnes and incremental oil recovery of roughly 40–50 million barrels. The primary goal of the PCOR demonstration was to evaluate the safety, storage performance, and monitoring methodologies associated with commercial CO₂-EOR operations. Extensive monitoring and verification activities included pressure and temperature tracking, geophysical surveys, groundwater monitoring, and geochemical analysis to confirm containment and characterize CO₂ behavior within the reservoir. While much of the injection utilized existing oilfield infrastructure, several additional wells were drilled or modified to support monitoring and characterization, including observation wells equipped with geophones and subsurface monitoring instrumentation. The project demonstrated that mature sandstone reservoirs undergoing CO₂-EOR can provide effective long-term storage while leveraging existing infrastructure and field operations.