Bell Creek

The Bell Creek Field is a large CO₂-enhanced oil recovery (CO₂-EOR) project located in Powder River County, southeastern Montana, within the Powder River Basin. The field produces primarily from the Cretaceous Muddy Sandstone (Newcastle Formation equivalent), a shallow-marine to deltaic sandstone reservoir characterized by high-quality channel sands, strong lateral continuity, and structural trapping along a gentle anticline. Discovered in 1967, Bell Creek initially produced under primary depletion followed by secondary recovery through extensive waterflooding programs. As reservoir pressure declined and significant residual oil remained, operators implemented tertiary recovery using miscible CO₂ injection to improve sweep efficiency and mobilize remaining hydrocarbons. CO₂ injection is conducted through Class II wells in a pattern flood configuration, often incorporating water-alternating-gas (WAG) cycles to manage mobility and optimize vertical conformance in the heterogeneous sandstone reservoir. CO₂ is delivered via regional pipeline infrastructure sourcing natural CO₂ from Rocky Mountain accumulations. Produced CO₂ is separated and recycled through surface facilities, while retained volumes contribute to long-term geologic storage through structural trapping, residual trapping, and dissolution in formation fluids. The Bell Creek CO₂ flood represents a major Rocky Mountain sandstone EOR project demonstrating the applicability of miscible CO₂ flooding outside carbonate reservoirs.