Circle Ridge Field lies in Fremont County, Wyoming, roughly sixty miles northwest of Riverton and entirely within the Wind River Indian Reservation. Discovered in 1923, it has produced from five stacked reservoirs — the Phosphoria, Tensleep, Ranchester, Darwin, and Madison — and cumulative recovery is reported at something over twenty-eight million barrels, well below the hundred-million figure sometimes attached to it. Its more important distinction for anyone researching ownership is jurisdictional: the minerals here are tribal, not fee, and they are administered on an entirely different legal footing.
The field was found in 1923, during the wave of Wind River Basin drilling that followed the proving of the basin’s Paleozoic reservoirs elsewhere in central Wyoming. Circle Ridge is a folded structure with a fractured Phosphoria and Tensleep section, and early operators worked it the way they worked every Wyoming anticline of the period: shallow first, deeper as equipment improved. The resulting field is a stack of five distinct reservoirs rather than one, each with its own drive mechanism and its own performance history across a century of production.
Because Circle Ridge sits on the Wind River Reservation, its development has always run through federal Indian mineral leasing rather than ordinary fee negotiation. Leases are approved and administered under Bureau of Indian Affairs authority for the benefit of the Eastern Shoshone and Northern Arapaho Tribes, with royalty accounting handled through federal systems. That framework governs who may explore, on what terms, and for how long, and it is the reason the field’s operating history reads as a series of long leaseholds rather than the constant lease-by-lease trading familiar from fee minerals in the rest of Wyoming.
Merit Energy operated Circle Ridge for many years under such a lease. In December 2019 the tribes decided not to renew it, and when the lease expired in 2021 the Eastern Shoshone and Northern Arapaho assumed full ownership of the field, including infrastructure reported to be worth several million dollars. It was a deliberate assertion of tribal control over reservation minerals after decades of leasing to outside operators, and it makes Circle Ridge a case study in how differently reservation oil fields are governed compared with fee acreage a few miles away.
Circle Ridge is a structural trap on the northwestern margin of the Wind River Basin, an asymmetric fold cut by faults that fractured the brittle carbonate section. Five formations have produced: the Permian Phosphoria, the Pennsylvanian Tensleep, the Ranchester and Darwin intervals, and the Mississippian Madison. Fracturing does much of the work here, because matrix permeability in these rocks is often poor and the natural fracture network is what connects it to the wellbore. That makes reservoir behaviour uneven from well to well and has kept the field a subject of fracture-characterization and reservoir-modeling research.
Recovery at Circle Ridge has relied on primary depletion and water injection rather than on miscible flooding. In fractured carbonate reservoirs of this type, injected water tends to travel along the fracture network, so sweep efficiency depends heavily on how well the fracture system is mapped and how injection is placed against it. That is the reason the field has attracted reservoir-modeling and fracture-characterization studies aimed at improving recovery. Over twenty-eight million barrels have been produced from the five reservoirs, a figure that reflects a long, patient, low-rate production history rather than any single boom.
The honest answer about Circle Ridge is a boundary rather than an offer. The field lies wholly within the Wind River Indian Reservation, where mineral interests are tribal trust or individually allotted acreage administered by the Bureau of Indian Affairs. Those are not conventional fee minerals, they cannot be conveyed like fee minerals, and they are not something we purchase. Plenty of Fremont County acreage outside the reservation boundary is ordinary fee mineral title. Where an interest is fee rather than trust or allotted, we buy minerals and royalties in Fremont County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
Not in the ordinary sense. Circle Ridge lies within the Wind River Indian Reservation, where minerals are tribal trust or allotted interests administered by the Bureau of Indian Affairs. Those interests are governed by federal Indian law rather than by Wyoming conveyancing, and we do not buy them.
The Eastern Shoshone and Northern Arapaho Tribes took full ownership after declining in December 2019 to renew the operating lease held by Merit Energy. The lease expired in 2021, and the tribes retained the field infrastructure that had been developed under it.
Published figures put cumulative recovery at more than twenty-eight million barrels from five reservoirs in the Phosphoria, Tensleep, Ranchester, Darwin, and Madison. That is far smaller than the giant Bighorn and Wind River Basin fields it is sometimes grouped with.