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Regional Geological setting and Previous Studies

The Deadwood Formation represents the deepest stratigraphic interval within the North Dakota portion of the Williston Basin, reaching depths of approximately 16,000 feet True Vertical Depth (ftTVD) in Western North Dakota with maximum formation thickness of 900 ft in Billings County (Anderson, 1988). It was deposited during the Late Cambrian to Early Ordovician (LeFever et al., 1987). The Deadwood Formation is mainly comprised of mixed siliciclastic-carbonate sequences in North Dakota (LeFever et al., 1987) and has been extensively studied and described by Carlson (1960), Lochman-Balk and Wilson (1967), Anderson (1988), and Sarnoski (2015). The Deadwood Formation unconformably overlies the Precambrian basement and is unconformably overlain by the Black Island Formation (Fig. 1).

 

Fig. 1. Stratigraphic Column of the Deadwood Formation
 

During deposition of the Deadwood Formation deposition in Late Cambrian, the North Dakota’s portion of the Williston Basin (Fig. 2) experienced cratonic subsidence accompanied by a gradual eustatic transgression, punctuated by episodes of minor regression that progressively overstep and onlap the cratonic platform (LeFever et al., 1987; Burgess, 2019). The depositional systems of the Deadwood Formation during this time included, but were not limited to, beach, foreshore to shoreface, tidal flats and channels, and shallow marine transition zones (Anderson, 1988). The deposition of the Deadwood Formation concluded in Early Ordovician time due to relative sea-level fall which may have been caused by change in stress fields (Leighton and Kolata, 1990).
 

Map

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Fig. 2. Paleogeographic map during Late Cambrian (Left) and Early Ordovician (Right) of the Williston Basin (Blakey, 2013). Red outline showing present-day North Dakota border.
 

As observed in Fig. 3, Subsurface observations suggest that the Deadwood Formation initially subsided in an elongated pattern during its early deposition but gradually transitioned into a more circular geometry in its later stages (LeFever, 1987).
 

Fig. 3. Regional depth map of Deadwood Formation. Obtained from 297 wells with Deadwood Formation marker.
 

Early work by Carlson (1960) divided the formation based on recognizable presence of 3 (three) lithologic units, a basal sandstone, intermediate carbonate and shale unit, and upper sandstone. As additional well data became available, Anderson (1988) was able to use Gamma Ray (GR) logs to informally divide the formation into six distinct lithostratigraphic units, designated as Member A through Member F. This distinction is based on “traceable” gamma-ray log characteristics, that, in the Deadwood Formation, represent variations in radioactivity attributable primarily to clay content and glauconite content (Fig. 4).
 

Fig. 4. Typical well log response and type log of the Deadwood Formation. Example from well NDGS #6228 Zabolotny No. 1-3-4-A (LeFever et al., 1987)
 

Deadwood Formation Depositional System

Anderson (1988) described the range of depositional systems within the Deadwood Formation in Fig. 5 as follows:

Diagram, schematic

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Fig. 5. Schematic depositional model of the Deadwood Formation (Anderson, 1988)
 

During Late Cambrian, from Member A – B, the Deadwood Formation is interpreted to have formed in a range of shallow marine to marginal marine settings, including beach and barrier island, braided fluvial, foreshore to shoreface, and tidal flat to tidal channel environments (Stanley, 1984; Mescher and Pol, 1985; Driese et al., 1981; Hiscott et al., 1984). Member B, characterized by abundant glauconite, has been interpreted as representing deposition in low-energy subtidal lagoons and tidal sand flats, based on analogous glauconitic sandstones and conglomerates from the Black Hills (Stanley, 1984; Lochman-Balk, 1970). The absence of desiccation features in the subsurface supports a dominantly subtidal lagoonal setting for Member B (Sepkoski, 1982).

By the Early Ordovician, from Member C – F, the region’s latitude had shifted, placing it in a tropical climate characterized by high rainfall and low evaporation (Ross, 1976). The siliciclastic and carbonate successions form asymmetrical vertical sequences that reflect the progradation of a siliciclastic shoreline and back-barrier environment over a shallow shelf and distal carbonate shoal.
 

Deadwood Formation and its relation to subsurface energy resource and storage

Deadwood Formation has remained relatively underexplored due to its low contribution to hydrocarbon production in North Dakota. Of the nearly 50,000 wells drilled in the state, only 297 vertical wells penetrated the Deadwood Formation, and 15 wells (Fig. 6) have produced from the Deadwood Formation/Winnipeg Group, yielding a cumulative production of approximately 500,000 barrels of oil—which accounts for less than 0.01% of North Dakota’s total oil production (Nesheim, 2019).
 

Fig. 6. Cumulative oil production from Deadwood Formation in North Dakota
 

Recently, however, interest in the Deadwood Formation has grown due to its potential for geothermal energy, the presence of helium resources, and feasible CO₂ storage in saline aquifers (Fig. 7).
 

Fig. 7. Distribution of non-hydrocarbon energy resources and subsurface storage projects across North Dakota. Red dots show wells with helium analysis, dark purple boundary shows DEEP Geothermal Project in North Dakota – Saskatchewan border, and dark blue boundary display CO2 storage projects across Central North Dakota.
 

Helium

In Saskatchewan, the helium potential of the Deadwood Formation was first identified in 1952, with commercial production beginning in 1963. Production has continued intermittently, with the most recent helium wells commencing operation in 2021 (Yurkowski, 2021).

A study by Nesheim and Kruger (2019) demonstrates that helium is present within major productive oil and gas reservoirs of the North Dakota portion of the Williston Basin. The data, originally compiled from the United States Bureau of Land Management (USBLM, 2019) gas database, include 65 total gas samples analyzed for measurable helium concentrations (>0.01%). Of these, 54 samples contained helium concentrations ranging from 0.01% to 0.09%, while the remaining eight samples exhibited concentrations between 0.10% and 0.46% (Fig. 6). The highest helium concentrations were identified within the Cambrian–Ordovician interval, particularly along structural trends such as the Nesson and Antelope anticlines, as well as the Newporte structures.
 

Geothermal

In addition to helium exploration, geothermal development has also been pursued in the Deadwood Formation in the Williston Basin, particularly in Saskatchewan, Canada. As Fig. 7 shows, Deep Earth Energy Production (DEEP) Corporation has drilled five geothermal wells to a depth of 11,500 feet, encountering formation temperatures of 250°F (Murphy, 2021).
 

Carbon, Capture, and Storage (CCS)

The Deadwood Formation has been utilized for CO₂ sequestration in Saskatchewan, serving as a reservoir for the CO₂ injected from SaskPower’s Boundary Dam Carbon Capture Facility (Nesheim, 2019). As of early 2023, the project successfully stored over 500,000 tonnes of CO2. Deadwood Formation has also been targeted as COstorage target in Carbon, Capture, and Storage (CCS) projects in North Dakota with a few projects as follows; PCOR Partnership (2003), Northwest McGregor Field Validation Test (2010), CarbonSAFE Phase II: North Dakota Integrated Carbon Storage Complex Feasibility Study (2017 – 2020), Roughrider Carbon Storage Hub (2023 – 2025), Project Tundra (2023), CarbonSAFE III (2020 – 2024), Coal Creek Carbon Capture (2023 – 2027). Announced October 21, 2024, the DOE awarded Project Tundra for advancement in CarbonSAFE IV: Site Construction.

Although most ongoing exploration and production activities for helium and geothermal resources within the Williston Basin are currently concentrated in Saskatchewan, the shared basin geometry between North Dakota and Saskatchewan suggests potential resource continuity beyond the country border. Thus, geological studies and exploratory efforts are actively underway in North Dakota to assess the extent of these resource plays and evaluate the feasibility of subsurface CO₂ storage. These investigations aim to determine whether the success observed in Saskatchewan can be replicated in North Dakota.

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Blakey, R. 2013. “North America Paleogeography.” http://cpgeosystems.com/nam.html.

Burgess, Peter M. 2019. “Phanerozoic Evolution of the Sedimentary Cover of the North American Craton.” In The Sedimentary Basins of the United States and Canada, 39–75. https://doi.org/10.1016/B978-0-444-63895-3.00002-4.

Carlson, C. G., and S. B. Anderson. 1965. “Sedimentary and Tectonic History of North Dakota Part of Williston Basin.” AAPG Bulletin 49 (11): 1833–1846.

Deepcorp. n.d. “About.” Accessed March 5, 2025. https://deepcorp.ca/about/.

Gerhard, Lee C., Sidney B. Anderson, Julie A. Lefever, and Clarence G. Carlson. 1982. "Geological Development, Origin, and Energy Mineral Resources of Williston Basin, North Dakota." AAPG Bulletin 66 (8): 989–1020.

Murphy, E. C., S. H. Nordeng, B. J. Juenker, and J. W. Hoganson. 2009. North Dakota Stratigraphic Column. Miscellaneous Series MS-91. Bismarck, ND: North Dakota Geological Survey.

Murphy, E. C. 2021. “Recent Rule Changes to Some of the Geological Survey’s Regulatory Programs.” North Dakota Geological Survey GeoNews, January 2021, 8p. https://www.dmr.nd.gov/ndgs/documents/newsletter/2021Winter/Recent_Rule… [accessed February 18, 2025].

Nesheim, T. O. 2021. “The Deadwood Formation: A Potential Stratigraphic Unit for CO₂ Sequestration.” North Dakota Geological Survey GeoNews, January 2021, 3p. https://www.dmr.nd.gov/ndgs/documents/newsletter/2021Winter/The_Deadwoo… [accessed February 17, 2025].

Yurkowski, M. M. 2021. Helium in Southern Saskatchewan: Geological Setting and Prospectivity. Saskatchewan Ministry of Energy and Resources, Saskatchewan Geological Survey, Open File Report 2021-2, 77p. and two Microsoft® Excel® files. 

Geoscience (North Dakota)

Alamooti, Moones, and Shane Namie. 2024. “Analysis of the Deadwood Formation in North Dakota: Applying Rock Physics.” In Proceedings of the 58th U.S. Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association. https://onepetro.org/ARMAUSRMS/proceedings/ARMA24/ARMA24/D022S021R011/549064.

Anderson, Douglas B. 1988. “Stratigraphy and Depositional History of the Deadwood Formation (Upper Cambrian and Lower Ordovician), Williston Basin, North Dakota.” Master's thesis, University of North Dakota. https://commons.und.edu/theses/5.

Bader, Jeffrey W., John H. Lake, and Anthony H. Sarnoski. 2022. Deadwood Formation (Cambrian/Ordovician) of North Dakota: A Core Atlas. Geo-Investigations No. 265. Bismarck, ND: North Dakota Geological Survey.

Bader, Jeffrey W. 2022. Stratigraphic Framework of the Deadwood Formation, North Dakota. Geo-Investigations No. 266. Bismarck, ND: North Dakota Geological Survey.

Carlson, C. G. 1960. “Stratigraphy of the Winnipeg and Deadwood Formations in North Dakota.” Thesis No. 50, University of North Dakota. https://commons.und.edu/theses/50.

Ellingson, J. B. 1995. “Depositional Environments and Paleogeography of the Winnipeg Group (Ordovician), Williston Basin, North Dakota.” Thesis No. 78, University of North Dakota. https://commons.und.edu/theses/78.

Hendricks, Michael L., Jacob D. Eisel, and Walter Fischer. 1998. “Deadwood and Winnipeg Sandstone Reservoirs, Newporte Field, Renville County, North Dakota.” In Eighth International Williston Basin Symposium, edited by J.E. Christopher, C.F. Gilboy, D.F. Paterson, and S.L. Bend, 129–138. Regina: Saskatchewan Geological Society Special Publication 13.

LeFever, Richard D., Stephen C. Thompson, and Douglas B. Anderson. 1987. “Earliest Paleozoic History of the Williston Basin in North Dakota.” In Fifth International Williston Basin Symposium, edited by C.G. Carlson and J.E. Christopher, 22–36. Regina: Saskatchewan Geological Society Special Publication 9.

LeFever, Richard D. 1996. “Sedimentology and Stratigraphy of the Deadwood-Winnipeg Interval (Cambro-Ordovician), Williston Basin.” In Paleozoic Systems of the Rocky Mountain Region, edited by M.W. Longman and Sonnenfeld, 11–28. Denver: Rocky Mountain Section, SEPM.

Lochman-Balk, C., and J. L. Wilson. 1967. “Stratigraphy of Upper Cambrian-Lower Ordovician Subsurface Sequence in Williston Basin.” AAPG Bulletin 51 (6): 883–917. https://doi.org/10.1306/5D25C0FB-16C1-11D7-8645000102C1865D.

Sarnoski, Anthony Henry. 2015. “The Stratigraphy and Depositional History of the Deadwood Formation, With a Focus on Early Paleozoic Subsidence in the Williston Basin.” Master's thesis, University of North Dakota. https://commons.und.edu/theses/1957.

Seager, O. A. 1942. “Stratigraphy of North Dakota: Discussion.” AAPG Bulletin 26 (8): 1414–1423. https://doi.org/10.1306/3D933554-16B1-11D7-8645000102C1865D.
 

Geoscience (non-North Dakota)

Buatois, Luis, and M. Gabriela Mángano. 2013. “Paleoenvironmental Variability of the Lower Paleozoic Earlie and Deadwood Formations in Subsurface Saskatchewan: A Preliminary Assessment.” In Summary of Investigations 2013, Volume 1, Saskatchewan Geological Survey, Saskatchewan Ministry of the Economy, Misc. Rep. 2013-4.1, Paper A-3, 8p.

Greggs, Darcie H. 2000. “The Stratigraphy, Sedimentology, and Structure of the Lower Paleozoic Deadwood Formation of Western Canada.” Master's thesis, University of Calgary.

Hein, Frances J., and Godfrey S. Nowlan. 1998. “Regional Sedimentology, Conodont Biostratigraphy, and Correlation of Middle Cambrian–Lower Ordovician(?) Strata of the ‘Finnegan’ and Deadwood Formations, Alberta Subsurface, Western Canada Sedimentary Basin.” Bulletin of Canadian Petroleum Geology 46 (4): 487–528.

Ichazo Demianiuk, Andrei. 2024. “Stratigraphy, Sedimentology, and Ichnology of the Middle Cambrian to Lower Ordovician Deposits in Subsurface Western Canada.” PhD diss., University of Saskatchewan. https://harvest.usask.ca/items/0259f135-24e0-44e6-bbd3-200a0b06819c.

Lake, John H. 2023. “Deposition of the Middle Cambrian Deadwood Formation and the Initiation of the Williston Basin.” AAPG Datapages/Search and Discovery Article #91206, Rocky Mountain Section Meeting, Bismarck, North Dakota, June 4–6, 2023.

Ross, R. J. Jr. 1957. “Ordovician Fossils from Wells in the Williston Basin, Eastern Montana.” U.S. Geological Survey Bulletin 1021-M. U.S. Government Printing Office. https://doi.org/10.3133/b1021M.

Steece, F. V. 1978. “Deadwood Formation in the Williston Basin, South Dakota.” In Montana Geological Society: Twenty-Fourth Annual Conference: 1978 Williston Basin Symposium: The Economic Geology of Williston Basin, 63-69. Montana Geological Society.
 

Helium

Nesheim, Timothy O., and Ned W. Kruger. 2019.Helium Trends in North Dakota.” Geologic Investigation No. 223. Bismarck, ND: North Dakota Geological Survey.

Yurkowski, M. M. 2021. "Helium in Southern Saskatchewan: Geological Setting and Prospectivity." Saskatchewan Geological Survey, Open File Report 2021-2, 77p. and two Microsoft® Excel® files.
 

Geothermal

Alamooti, Moones, Chioma Onwumelu, and Shane Namie. 2023. “The Analysis of Water Chemistry for Geothermal Exploration: A Case Study of Deadwood Formation.” AAPG Search and Discovery Article #91206, Rocky Mountain Section Meeting, Bismarck, North Dakota, June 4–6, 2023.

Lake, John H., and Arden Marsh. 2022. “The Potential for Geothermal Energy, CO₂ Disposal, and Helium in the Deadwood and Winnipeg Sands.” In Twenty-Ninth Williston Basin Petroleum Conference: Core Workshop Volume, 29–33. Bismarck, ND: North Dakota Geological Survey.

Namie, Shane, Moones Alamooti, Chioma Onwumelu, Nnaemeka Ngobidi, and William Gosnold. 2022. “EGS Opportunities in North Dakota's Sedimentary Basin: Analysis of the Deadwood Formation.” GRC Transactions 46. https://www.researchgate.net/publication/368653028.

Namie, Shane, Moones Alamooti, and Shane Eiring. 2023. “Unlocking the Potential of Geothermal Energy in North Dakota's Williston Basin: Developing a Correction Method for Bottom Hole Temperatures.” GRC Transactions 47. https://www.researchgate.net/publication/375553414.
 

CCS

Nesheim, Timothy O. 2021. “The Deadwood Formation: A Potential Stratigraphic Unit for CO₂ Sequestration.” North Dakota Geological Survey Geo News 48 (1): 11–13.

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Last Updated: 04/29/2025.