Region: Northern Midcontinent Williston Basin Province This description of the Williston Basin Province is from the U. S. Geological Survey 1995 National Assessment of United States Oil and Gas Resources (available on CD-ROM from the U.S.G.S. as Digital Data Series DDS-30, Release 2).

Williston Basin Province

Introduction

The Williston Basin is a structural-sedimentary intracratonic basin located on the western shelf of the Paleozoic North American craton. The present-day basin occupies a large segment of the northern Great Plains and extends northward into Canada. The basin region is a generally flat lying, moderately dissected plain with minimum topographic relief. The basin is bordered on the east and southeast by the Canadian Shield and the Sioux Uplift. The western and southwestern borders are defined by the Black Hills Uplift, Miles City Arch, Porcupine Dome, and Bowdoin Dome. The United States part of the basin covers approximately 143,000 sq mi with a total sedimentary rock volume of approximately 202,000 sq mi. Sedimentary rocks of Cambrian through Holocene age are present in the basin. Maximum thickness of Phanerozoic rocks is greater than 16,000 ft in North Dakota. The basin began subsiding during Late Cambrian or Early Ordovician time and has continued to subside through the remainder of geologic time, with the subsiding center remaining approximately in the same position in northwestern North Dakota throughout that time.

Sporadic pre-World War II exploration activity took place in the Williston Basin, but the few deeper wells drilled were unsuccessful. Shallow gas was discovered in the Upper Cretaceous Eagle Sandstone on the Cedar Creek Anticline in southeastern Montana in 1916. This resource was subsequently developed and marketed by the Montana Dakota Utilities Company. Following World War II, several major oil companies renewed their interest in the deeper possibilities of the basin. This activity culminated in the 1951 discoveries of the Beaver Lodge field by the Amerada Oil Company on the Nesson Anticline in North Dakota and the Richey and Southwest Richey fields by Shell Oil Company in eastern Montana. Further discoveries followed quickly, on the Nesson Anticline trend by Amerada and other companies and on the Cedar Creek Anticline by Shell, which had contracted with Montana Dakota Utilities Company and the Northern Pacific Railroad for the deep rights on the anticline. Early production on the Nesson Anticline was mainly from Mississippian carbonate reservoirs and on the Cedar Creek Anticlines from Ordovician and Silurian carbonate reservoirs. By the early 1960's approximately 25 large fields of greater than 15 MMBO had been discovered (table 1), and a major part of the basin's reserves had been found. Intensive exploration by numerous companies continued until the early 1960's when economic factors slowed the pace of activity. With the strong oil price rise in the early 1970's, exploration again intensified and several important large discoveries and many smaller ones were made, particularly in the deeper Red River Ordovician and the Silurian and Devonian reservoirs.

Table 1. Ultimate Recovery--fields 15 million barrels of oil or greater in Williston Basin.

Field and date of discovery		Reservoirs						Estimated Ultimate Recovery
								(MMBO)	(BCFG)	(MMBNGL)
Beaver Lodge, N. Dak.	1951	Mm,	D,	Or,	S			130	115	47
Pine, Mont.,	1952	Or,	Mm					127	20	?
*** Pennel, Mont.	1955	Si,	Or,	Mm				115	?	?
*** Cabin Creek, Mont.	1953	S,	Or,	Mm				115	?	?
Little Knife, N. Dak.	1977	Mm,	Mb,	Dd,	Or			96	120	15
Tioga, N. Dak.,	1952	Mm,	Dd,	Or				77	43	17
Blue Buttes, N. Dak.,	1955	Mm,	Dd,	S,	Os,	Or		53	36	5
Charlson, N. Dak.	1952	Mm,	Mb,	D,	S,	Os,	Or	52	100	11
Poplar East, Mont.	1952	Mm,	Mh,	Dn				48	40
* Big Stick, N. Dak.	1979	Mm,	Mb,	Dd				46	53	?
Newburg, N. Dak.	1955	Trs						43	3
Fryberg, N. Dak.	1953	Pt,	Mm,	Or				42	18
Antelope, N. Dak	1953	Mm,	Dtf,	Dd,	S,	Or		41	16	4
**Lookout Butte, Mont.	1961							35	?
Dickinson, N. Dak.	1958	Pt,	Mm					27	8
Glenburn, N. Dak.	1958	Mm						25	0
Mondak & Mondak West, N. Dak.	1976	Mm,	Mb,	Dd,	Or			25	10
Rough Rider, N. Dak.,	1959	Mm						16	8
Sherwood, N. Dak.	1958	Mm,	Mb,	Dd,	S,	Or		23	19-28	3
Buffalo, S. Dak.	1954	Or						22	40	0
So. Westhope, N. Dak.	1957	Trs,	Mm					22	4
Elkhorn Ranch, N. Dak.	1961	Mm,	Mb,	Or				21	17	2
North Tioga, N. Dak.	1957	Mm,	Mb,	Os				19	6	?
Indian Hill, N. Dak.	1978	Mm,	Dn,	Dd,	Os,	Or		18	17
Flat Lake, Mont.	1964	Mm						17	17
N. Elkhorn Ranch, N. Dak.	1981	Mm,	Mb					17	10
*** Little Beaver, Mont.,	1957	Or						16	?
Rival, N. Dak.	1957	Mm						16	8
Wiley, N. Dak.	1958	Mm						16	0
Glendive, Mont.	1952	Si,	Or					15	15
** T.R., N. Dak.,	1978	Mm,	Trs					15	0
Hawkeye, N. Dak.	1955	Mm,	Or					15	4	?
* Capa, N. Dak.	1953	Mm,	S					15	8

Trs--Spearfish	Mb--Bakken	Dn--Nisku	Os--Stonewall
Pt--Tyler	D--Devonian	Dd--Duperow	Or--Red River
Mm--Madison	Dtf--Three Forks	S--Silurian

Sources: Montana Oil & Gas Commission, North Dakota Geological Survey, NRG Associates.
MMBO--Million barrels oil; BCFG--Billion cubic feet gas; MMBNGL--Million barrels natural gas liquid

*--Beaver Lodge area fields, including Beaver Lodge, Capa, Delta, and Hofflund, are reported as 131 MMBO, 380 BCFG, and 46 MMBNGL.
**--Billings Nose area fields, including Big Stick, Four Eyes, Frank's Creek, St. Jamobs, T.R., Treetop, and Whiskey Joe, are reported as 80 MMBO, 74 BCFG, and 8 MMBNGL.
***--Cedar Creek Anticline fields, including Cabin Creek, Clear Creek, Little Beaver, Little Beaver East, Lookout Butte, Monarch, and Pennel, are reported as 305 MMBO, 351 BCFG, and 7 MMBNGL.

In addition to these main plays and the subplays associated with them, others worthy of study include hydrodynamic plays, fracture belts, salt solution trends, impact structures, basement trends, tight gas reservoirs, and others.

Unconventional continuous-type plays are also important in the Williston Basin. For this province, J.W. Schmoker describes four continuous-type plays: Bakken Fairway, Bakken Intermediate, Bakken Outlying, and Southern Williston Basin Margin-Niobrara Shallow Biogenic.

Acknowledgements

Several individuals provided helpful information and discussions beneficial to this study. They are: T.J. Heck and S.B. Anderson, North Dakota Geological Survey; J.H. Clement and J.W. Taylor, Shell Oil Company, retired; T.S. McClellan, Meridian Oil Company; J. R. Fanshawe, consultant, Billings, MT. Scientists affiliated with the American Association of Petroleum Geologists and from various State geological surveys contributed significantly to play concepts and definitions. Their contributions are gratefully acknowledged.

References

Fischer, D.W., and Bluemle, J.P., 1988, Oil exploration and development in the North Dakota Williston Basin, 1986-1987 update: North Dakota Geological Survey, Miscellaneous Series, no. 72, 36 p.

Gerhard, L.C., Anderson, S.B., LeFever, J.A., and Carlson, C.G., 1982, Geological development, origin, and energy mineral resources of Williston Basin: American Association of Petroleum Geologists Bulletin, v. 66, p. 989-1020.

Lockridge, J.P., and Pollastro, R.M., 1988, Shallow Upper Cretaceous Niobrara gas fields in the eastern Denver Basin, in Goolsby, S.M., and Longman, M.W., eds., Occurrence and petrophysical properties of carbonate reservoirs in the Rocky Mountain region: Denver, Rocky Mountain Association of Geologists, p. 63-74.

Lockridge, J.P., and Scholle, P.A., 1978, Niobrara gas in eastern Colorado and northwestern Kansas, in Pruit, J.D., and Coffin, P.E., eds., Energy resources of the Denver Basin: Denver, Rocky Mountain Association of Geologists, p. 35-49.

Montana Natural Resources and Conservation Department, Oil and Gas Conservation Division, 1993, Annual Review, 1992: 57 p.

North Dakota Industrial Commission, Oil and Gas Division, 1993, Oil in North Dakota, 1992 Production Statistics: 575 p.

Peterson, J.A., 1988, Geologic summary and hydrocarbon plays, Williston Basin, Montana, North and South Dakota, and Sioux Arch, South Dakota and Nebraska, U.S.: U.S. Geological Survey Open-File Report 87-450-N, 43 p.

Peterson, J.A., Longman, M.W., Anderson, S.B., Pilatzke, R.H., and Kent, D.M., eds., 1987, Williston Basin, anatomy of a cratonic oil province: Rocky Mountain Association of Geologists, 440 p.

Shurr, G.W., and Rice, D.D., 1987, Geologic setting and potential for natural gas in the Niobrara Formation (Upper Cretaceous) of the Williston Basin, in Peterson, J.A., ed., Williston Basin--exploration model for a cratonic petroleum province: Denver, Rocky Mountain Association of Geologists, p. 245-257.

South Dakota Department of Environment and Natural Resources, 1993, Oil, gas, and water production, Second Half 1992: 47 p.

Tonnsen, J.J., ed., 1985, Montana Oil and Gas Fields Symposium, Vols. I and II, M.G.S., Montana Geological Society, Billings, Mont., 1217 p.