William H. Curry

Teapot Dome--Past, Present, and Future

The Teapot Dome field is the 99th largest oil field in the United States with a proved reserve of 42,515,000 bbl, yet the field is sparsely drilled and underdeveloped. The writer credits Naval Petroleum Reserve No. 3 with 38 million bbl of future reserves. The long history of Teapot Dome since the early 1900s, sometimes turbulent, sometimes dormant, was marred by government scandal, akin to Watergate in notoriety, in the 1920s. Harry F. Sinclairs Mammoth Oil Company obtained leases from the Department of the Interior in a fraudulent manner which led to prison sentences for some of the principals. Oil production in the Teapot Dome field is from three formations--the shallow Shannon at depths of 400 to 1,000 ft (122 to 305 m); the Second Wall Creek member of the Frontier Formation at 2,500 to 3,000 ft (362 to 914 m); and the Tensleep Sandstone at 5,500 ft (1,676 m). The Second Wall Creek is the principal producing sandstone and has the greatest future production potential. Current production is small. As of December 1973, each of the 42 Navy wells averaged 4.4 b/d from the Shannon Sandstone, and 49 offset wells averaged 2.2 b/d each. In the Second Wall Creek, each of the 23 Navy wells averaged 10 b/d and 8 offset wells averaged 14.9 b/d each. Total daily production was 416 bbl and grand total for Teapot Dome through December 1975 was 7,762,709 bbl.

Tertiary Correlations in Bighorn and Uinta Basins, Wyoming and Utah: ABSTRACT

Electrical accessory curves have been used to map the Mesaverde, Lance-Meeteetse, Fort Union, and Willwood Formations in the Bighorn basin of Wyoming. These subsurface mapping units have been correlated to mapped outcrops on the flank of the basin. Recent authors have concluded that the basin started to subside during upper Lance deposition; however, I conclude that most subsidence along the axis of the basin was in late Paleocene and Eocene times (upper Fort Union and Willwood). Electrical accessory curves also were used to map the Mesaverde, Wasatch, Green River, Uinta, and Duchesne River Formations in the Uinta basin of Utah. These subsurface formations have been correlated to mapped outcrops on the south flank of the basin. Thickening of the Uinta and Duchesne River Formations into the basin indicates that the main subsidence along the axis of the basin was in late Eocene time. End_of_Article - Last_Page 825------------

Resistivity Mapping of Sandstone Stratigraphic Traps: ABSTRACT

Many Cretaceous stratigraphic oil accumulations of Wyoming may be mapped with log resistivity, because the clay-rich edges of sandstone bodies have lower resistivity and the clay poor centers of the sandstones have higher resistivity. Although many factors affect log resistivity, variation of the clay content of a sandstone body causes several orders of magnitude change in resistivity in and around a given stratigraphic trap. Resistivity maps generally agree with SP isopach maps, but tend to show the location of the most porous and permeable clay-poor sandstones, rather than the total sand thickness. Resistivity maps are also useful when no SP is evident outside the developed sand body or when clay fill makes SP unreliable. Although the presence of carbonate cement, coals, and lignites, etc., complicate interpretation of resistivity maps in some formations, the tool is usually effective in simple clay-quartz formations. The tool is particularly useful during development drilling of a stratigraphic trap. The use of resistivity mapping is illustrated with a number of Muddy and Dakota stratigraphic oil fields in the Powder River basin of Wyoming at Hilight, Recluse, South Glenrock, Gas Draw, and Coyote Creek. End_of_Article - Last_Page 956------------

Oil and gas developments in northern Rockies in 1970

Both exploratory and development drilling declined in the Northern Rockies during 1970 but number of discoveries was not significantly lower. The Powder River basin remained the most active area with more new-field discoveries than any other province. Stratigraphic traps, especially in Cretaceous sandstones, continued as most popular exploration objectives. If more exploration and development money is spent next year, new reserves of oil and gas may be expected.

Oil and Gas Developments in Northern Rockies in 1969

Drilling in the Northern Rockies continued at a high level and success rates were higher than in 1968 for Wyoming, Montana, and North Dakota. The Powder River basin remained the most active area and accounted for more new-field discoveries than any other province. Stratigraphic traps continue to hold the greatest interest throughout the region, particularly the search for Cretaceous sandstone reservoirs. Activity should remain at a high level throughout the coming year.

Oil and Gas Developments in Northern Rockies in 1968

Exploration drilling increased sharply in 1968. The success in Wyoming continued to be high, but in Montana and North Dakota was rather low because many unsuccessful wells were drilled in areas of sparse control as part of multiwell stratigraphic test programs. Twenty-six discoveries in the Muddy Sandstone in the Powder River basin of Wyoming highlighted the year. Interest was spurred in the deeper part of the Williston basin by discoveries in the Red River Formation in eastern Montana. Considerable leasing and drilling activity was in progress along the boundary between Montana and North Dakota at year end. Although large lease blocks were taken in South Dakota in 1967 and 1968, drilling activity is still at a low level. The need to evaluate these holdings should produce considerable drilling in 1969. There was no drilling in Idaho in 1968.

Developments in Northern Rockies in 1967

Exploratory drilling decreased in 1967 but success ratios were better in Wyoming and North Dakota. Development drilling increased, but production declined. Developments late in 1967, however, should result in an increase in all categories in 1968. The most significant developments in the Northern Rockies were the discoveries in the Lower Cretaceous Muddy sand at Bell Creek in Montana, and Recluse and Kitty in Wyoming. These discoveries have led to lease and drilling activity in Montana, North Dakota, South Dakota, and Wyoming, which will lead to extensive exploration in these states in 1968. The significance of Bell Creek is the fact that this large accumulation was found through a program of stratigraphic drilling and could not have been found by any other conventional e ploration program. The northern Powder River basin continues to be the most active exploration area in Wyoming; however, the target for exploration has shifted from the Minnelusa to the Muddy. New Minnelusa pools continue to be found adding to the previously discovered reserves. The discovery of a significant accumulation in southeastern Montana at the Bell Creek field sparked the drilling of wildcat wells based on scant geologic information. The result was several dry holes and no additional discoveries which caused a low discovery ratio for the area and state. The Tiger Ridge gas field appears to be a large field by Montana standards, and probably will prove to be one of the larger gas accumulations in the state. Discoveries and new pays in the Williston basin assure continued exploration in this area both central Montana and the Sweetgrass arch had some exploratory activity and success. North Dakota remains an attractive area in which to operate because of shallow depths, low drilling costs, available acreage, and a favorable market and price for oil. Continued exploration for and discoveries in deeper pays both on and off the Nesson anticline offer incentives to keep deeper exploration alive in search for large stratigraphic traps. Bell Creek already has touched off major lease activity in this state which will lead to considerable Newcastle (Muddy) exploration in 1968. South Dakotas reserves still elude the explorationist; the impact of Muddy discoveries in Wyoming and Montana probably will lead to exploration for this objective in South Dakota in 1968. There was no drilling in Idaho in 1967.