Bell Creek Field lies in the southeastern corner of Powder River County, Montana, near the Wyoming line. Discovered in June 1967, it produces from the Cretaceous Muddy Sandstone — a clean, high-porosity sand roughly twenty feet thick that made Bell Creek one of the largest oil fields ever found in Montana. After decades of primary and waterflood production the field was converted to a carbon dioxide flood, which is why a mineral interest here behaves nothing like a Bakken royalty a few hundred miles north.
Bell Creek was discovered in June 1967, and the field developed rapidly through the following years into one of Montana’s most important producers, eventually supporting more than four hundred oil wells. The reservoir was exceptional by any standard: a Muddy Sandstone averaging roughly eighteen to twenty feet of pay with porosity near twenty-seven percent, the kind of rock that flows freely without stimulation and rewards straightforward development.
Primary production drew down reservoir pressure over the following decades, and waterflooding was introduced to maintain it and sweep additional oil toward producers. That extended the field’s life considerably, but by the turn of the century Bell Creek was a mature waterflood with a great deal of oil still trapped in pore space that water could not reach. The remaining target was large enough to justify a far more expensive recovery method.
Denbury Resources acquired the field and converted it to carbon dioxide flooding, with CO2 delivered by the Greencore pipeline built to move carbon dioxide from Wyoming into southeastern Montana. Injection into the Muddy sandstone takes place at roughly 4,500 feet. The field has also been studied as a site for long-term geologic carbon storage. ExxonMobil acquired Denbury in 2023, taking on Bell Creek along with the rest of Denbury’s CO2 enhanced oil recovery portfolio.
The reservoir at Bell Creek is the Cretaceous Muddy Sandstone, a clean shoreline sand body with average net pay in the range of eighteen to twenty feet and porosity near twenty-seven percent — outstanding conventional reservoir quality. Water saturation is low and permeability is high enough that wells flowed readily on primary production. The trap is stratigraphic, controlled by the geometry of the sand body itself. Depth is roughly 4,500 feet, shallow enough to keep drilling and injection costs manageable through multiple recovery phases.
Carbon dioxide flooding works by injecting CO2 that mixes with the oil left behind after waterflooding, swelling it and reducing its viscosity so it can move through pore space water alone would bypass. At Bell Creek the CO2 arrives through the Greencore pipeline and is injected into the Muddy sandstone around 4,500 feet. For a royalty owner, the practical result is production that continues at meaningful rates half a century after discovery, backed by an operator with long-term capital committed to the flood.
A Bell Creek royalty is a long-life, low-decline asset — the opposite of a shale interest. CO2 floods produce slowly and steadily for decades, so value depends on how a buyer models the remaining flood response and the operator’s continued investment, not on near-term flush production. Interests in a field this old are often held by heirs several generations removed from the original lessors. We buy minerals and royalties in Powder River County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
It sustains the production your royalty is paid on. Carbon dioxide recovers oil that waterflooding leaves behind, which extends the paying life of the field by decades. How injection and processing costs interact with your royalty depends on the specific language in your lease, but the dominant effect at Bell Creek has been continued production.
Denbury Resources developed the CO2 flood and built the field into a core part of its enhanced oil recovery portfolio. ExxonMobil acquired Denbury in 2023, so the field has been associated with ExxonMobil since that transaction.
Because the reservoirs behave completely differently. A CO2 flood in a conventional sandstone produces a slow, shallow decline measured in decades. A horizontal Bakken well loses most of its rate in the first couple of years. Both can be valuable, but they are priced on entirely different assumptions about time.