Antelope Field in McKenzie County, North Dakota holds a peculiar place in petroleum history. Discovered in 1953, it produced from what North Dakota geologists called the Sanish sand — a weathered, naturally fractured interval at the top of the Devonian Three Forks Formation. Wells there flowed at rates the rock had no business supporting, and the field became a long-studied curiosity. More than fifty years later the industry learned to create those fractures artificially, and the Three Forks became one of the largest oil targets in the country.
Drilling on the Antelope structure in 1953 encountered oil in an interval directly beneath the Bakken shales that no one had expected to produce. The Sanish sand, as it came to be known, is the weathered and brecciated top of the Three Forks Formation, and at Antelope it was naturally fractured enough to deliver commercial rates from vertical wells. Papers written in the following decades described the pool as nearly unique in the Williston Basin, a productive reservoir that log analysis alone could not explain.
For the rest of the twentieth century Antelope remained an interesting outlier rather than a template. Attempts to repeat the result elsewhere in the basin generally failed, because the natural fracturing that made Antelope work was not present in most places. The field produced on primary depletion, and the geology reports it generated became standard references for anyone studying the Bakken and Three Forks section — including, eventually, the engineers who worked out how to fracture the rock deliberately.
When horizontal drilling with multi-stage hydraulic fracturing arrived in the late 2000s, the same acreage came back into play. Operators drilled Middle Bakken and Three Forks laterals across the Antelope area, and the interval that had once been a geologic anomaly became routine development. Owners with interests dating to the 1950s in this field have seen it produce under two entirely different technologies, separated by more than half a century.
The Sanish sand at Antelope is the weathered, fractured upper surface of the Devonian Three Forks Formation, lying directly beneath the organic-rich Lower Bakken shale that sourced its oil. Natural fracturing in that interval, associated with structure and steep basin dip, gave the rock enough flow capacity to produce from vertical wells — something the unfractured Three Forks cannot do. Above it sit the Bakken shales and the Middle Bakken siltstone, and Madison carbonates lie higher still in the section.
Antelope produced on primary depletion rather than under a flood; the natural fracture network that made the pool productive also made conventional pressure maintenance difficult to engineer. Modern recovery in the area comes from horizontal drilling instead — Middle Bakken and Three Forks laterals stimulated with multi-stage fracturing that reproduces artificially what nature had already done at Antelope. Recovery factors in those wells remain low, and additional barrels come from more wellbores rather than from injection.
Interests in Antelope Field can be genuinely old, tracing to leases signed in the years right after the 1953 discovery, which means fractional ownership across many heirs is common. Present value generally rests on the horizontal Bakken and Three Forks wells and on the locations still undrilled beneath the tract rather than on the historical production that made the field famous. We research heirship and title at our own expense. We buy minerals and royalties in McKenzie County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
It is an informal North Dakota name for the weathered, naturally fractured top of the Devonian Three Forks Formation, first produced at Antelope Field in 1953. It shares the name with the Sanish Field in Mountrail County, but the two are different things — one is a rock interval, the other an administrative field name.
Yes, in limited places. Oil was produced from the Bakken and adjacent Three Forks in North Dakota beginning in the 1950s, but only where natural fracturing gave the rock enough permeability. What changed in the 2000s was the ability to create that permeability with horizontal wells and multi-stage fracturing anywhere in the play.
It can. Old conventional production may have stopped, but the undrilled Bakken and Three Forks inventory beneath the same acreage is often what a buyer is pricing. It is also worth checking whether royalties are sitting in suspense from an unresolved chain of title. We look at both when we prepare an offer.