Wind River Basin Geology

The Wind River Basin, in central Wyoming, is an east-west elongate structural basin of typical Laramide style, 115 km (71 mi) wide by 300 km (186 mi) long. The primary basin axis trends northwest-southeast, and is asymmetrically located near the northern basin margin. The basin is bounded by the Wind River Range on the west, the Owl Creek Mountains on the north, the Casper Arch to the east, and the Granite Mountains to the south.

Significant deformation occurred in the Wind River Basin during the Laramide orogeny that resulted in a basin center greater than 7,620 m (25,000 ft) deep, beds dipping 10–20 degrees toward the basin center on the south and western margins, and near-vertical to overturned strata on the north and eastern margins (Keefer, 1969). A thick succession of undeformed post-Laramide basin-fill strata was deposited unconformably on the pre-Laramide (pre-Eocene) rocks.

In the Wind River Basin, hydrocarbon traps typically consist of structural features such as domes, anticlines, or faulted anticlines (Keefer, 1969) situated on the basin margins in rocks deposited previous to or coincident with Laramide-age faulting. Other types of structural traps include anticlines or domes near the basin axis, traps beneath the basin-bounding thrust faults, or sub-thrust plays (Fox and Dolton, 1996).

Tensleep Sandstone
Photo mosaic of the Tensleep Sandstone in Wind River Canyon. [Credit: WSGS]

Some purely stratigraphic traps are also found in the Wind River Basin. The most frequent stratigraphic traps are lateral up-dip (to the east) facies changes in the Phosphoria, Park City, and Goose Egg formations. Others include sandstone pinch-outs in the reservoirs of the Frontier Formation, Mesaverde Group, and Muddy Sandstone, as well as vertical and lateral cementation variations in Tensleep Sandstone reservoirs. In some cases, structural traps are enhanced by the effects of stratigraphic-trapping. For example, oil and natural gas in Morrison Formation sands are held by a combination structural-stratigraphic trap on the nose of a domal structure in the Poison Spider West field (Gouger, 1989).

The Tensleep Sandstone and Phosphoria and Park City formations comprise the primary reservoir rocks in the basin. The bulk of the hydrocarbons in these formations were sourced from the black shales of the Mead Peak and Retort members of the Phosphoria Formation in western Wyoming and eastern Idaho (Sheldon, 1967; Stone, 1967; Kirschbaum and others, 2007). Migration began soon after generation, and may have been associated with Sevier orogenesis. Hydrocarbons moved up-dip, likely via the porous and permeable Tensleep Sandstone, into the area that is now the Wind River Basin and were trapped by the overlying impermeable Goose Egg Formation (Stone, 1967; Kirschbaum and others, 2007).  Laramide faulting and folding was responsible for the subsequent rearrangement of the hydrocarbons into their present day structural and stratigraphic traps. Phosphoria-sourced hydrocarbons are commonly high in sulfur, exhibit high American Petroleum Institute (API) gravities, and are classified as Type-IIS (Kirschbaum and others, 2007).


Oil production in Wyoming began in the Wind River Basin with the completion of the Mike Murphy #1 well in 1884, just five years after America's first commercial oil well was drilled. The Mike Murphy #1 well was completed in the Chugwater Group to a depth of 91 m (300 feet; Mullen, 1989; De Bruin, 2012), and was the discovery well for the Dallas (or Dallas Dome) field in the southwestern Wind River Basin. The basin also contains the first logged well in Wyoming (Atlantic Richfield Company Muskrat 2C, September 1936) and the deepest completed well in the Rocky Mountain region (Burlington Resources Big Horn 1-5, Madden field), which was completed between 23,758 and 23,902 ft in the Madison Limestone.

Of the 118 named fields in the Wind River Basin, 63 primarily produce oil and 55 primarily produce natural gas from reservoirs ranging in age from Mississippian to Eocene (WSGS oil and gas map). Oil production in the Wind River Basin declined from 1978 through 1994, but has since remained relatively steady at 3–5 million barrels per year (WOGCC, 2024). This consistent production is due to the use of efficient secondary and tertiary production techniques such as the CO2-EOR project at Beaver Creek field.

Chugwater Group
Triassic Chugwater Group near Burris, WY. [Credit: WSGS]

Future Development

Although it is possible that small undiscovered petroleum accumulations exist in the Wind River Basin (Fox and Dolton, 1996), it is more likely that any significant future increases in oil production will be the result of improved recovery methods.

After fifteen years of declining gas production, natural gas production in the Wind River Basin began to stabilize in 2020, in part due to the 4,250 well-Moneta Divide project being developed in northeastern Fremont County and northwestern Natrona County by Aethon Energy and Burlington Resources. The Wind River Basin has since maintained a 6–7 percent annual contribution to Wyoming’s total natural gas production (WOGCC, 2024).



Rachel Toner,

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