CSPG-CSEG Joint Annual Conference
Calgary, Alberta, Canada
May 14-17, 2007

Conference link: http://www.geoconvention.org

The Devonian Three Forks Formation: Manitoba’s Newest Oil Play

Michelle P.B. Nicolas
Manitoba Mineral Resources
360-1395 Ellice Avenue, Winnipeg MB, R3G 3P2

The Sinclair Field (Townships 7 to 8, Ranges 28 to 29W1) is the newest oil field discovery in Manitoba and has greatly expanded in size and production since its discovery in 2004. The oil field had been previously explored in the 1960’s, but the pay was missed by early exploration efforts. Proven and probable reserves are estimated at 3.8 million m3.

The Devonian Three Forks Formation is a cyclical transgressive-regressive sequence of shaley, silty dolarenite, interbedded with shale and brecciated in many places. Deposition of the Three Forks was influenced by several weathering events due to transgressive and regressive cycles and basin tectonics. It is subdivided into four units. Unit 1 is the lowermost unit and the most widespread, and is the most oxidized and weathered of the units; this unit is productive as a secondary reservoir in small isolated pools. Unit 2 is an interbedded siltstone and shale, massive shale and occasionally brecciated, and is productive as a secondary reservoir at the Sinclair Field and Daly Field (Townships 9 to 10, Ranges 27 to 29W1). Unit 3 is a red-brown highly oxidized silty shale. Unit 4, the uppermost unit represented in Manitoba, is an interbedded siltstone and silty shale with thick subunits of highly distorted and brecciated siltstone beds. Unit 4 is the primary and most productive reservoir at Sinclair Field. Units 2 and 4 are productive at the unconformity surface as a subcrop-type play. In contrast, the production from Unit 1 is due to a stratigraphic-type play.

Thinning of the Three Forks Formation and truncation of the best reservoir units towards the east suggest the eastern expansion of the Sinclair Field may be limited. Mapping of these units towards the south along Range 29W1 indicates that Unit 4 is preserved up to the Manitoba-North Dakota international border, thereby extending the reservoir potential to the south. A recent successful Three Forks completion in Township 4 Range 29W1 provides hope for future exploration efforts south of Sinclair Field. North of Sinclair Field, the Three Forks has proven productive up to Kirkella Field (Township 12 Range 29W1) with two new Three Forks pools in 2006.

The sub-Paleozoic extension of the Precambrian Superior Boundary Zone (SBZ) runs north-south in the study area. The Birdtail-Waskada Axis (BWA) runs roughly through the middle of the southern extent of the SBZ. Isopach, structural and geophysical evidence suggest the presence of faults running parallel to the SBZ eastern and western margins; these faults were active at the end of the Devonian. Movements along these faults caused the preservation of the primary reservoir (Unit 4) of the Three Forks Formation east and west of the SBZ margins, while secondary reservoir unit (Unit 2) was exposed as a plateau on the BWA. The preservation of Unit 4 in some wells east of the BWA margin, along the SBZ margin opens up the possibility that, under the right trapping conditions, there may be another Sinclair-type play yet to be discovered east of Range 24W1.


Paper presented at the CSPG-CSEG Joint Annual Conference
May 14-17, 2007
Calgary, Alberta, Canada

cspg_2007_mnicolas_tf_poster.pdf (10.4 MB)
Nicolas, M.P.B. (2007): The Devonian Three Forks Formation: Manitoba’s Newest Oil Play. Poster.

Papers presented at the Saskatchewan and Northern Plains Oil and Gas Symposium
October 16-18, 2006
Regina, SK

23_palombi.pdf  (1.6 MB)
Palombi, D.D. and Rostron, B.J. (2006): Regional hydrochemistry of Lower Paleozoic aquifers in the northern portion of the Williston Basin, Saskatchewan–Manitoba; in Gilboy, C.F. and Whittaker, S.G. (eds.), Saskatchewan and Northern Plains Oil & Gas Symposium 2006, Saskatchewan Geological Society Special Publication 19, p201-209.

christopher_et al_colorado_paper.pdf  (2.2 MB)
Christopher, J., M.Yurkowski, M.Nicolas, and J.Bamburak, 2006: The Cenomanian-Santonian Colorado Formations of Eastern Southern Saskatchewan and Southwestern Manitoba.

kreis_et_al_bakken-torquay_paper.pdf  (8.9 MB)
Kreis, K., A. Costa, and K.Osadetz, 2006: Hydrocarbon Potential of Bakken and Torquay Formations, Southestern Saskatchewan.

nicolas_threeforks_paper_mb.pdf  (1 MB)
M.Nicolas, 2006: Petroleum Geology of the Devonian Three Forks Formation, Sinclair Field and Surrounding Area, Southwestern Manitoba
(revised core workshop paper)

nicolas_threeforks_poster_mb.pdf  (2.9 MB)
M.Nicolas, 2006: Petroleum Geology of the Devonian Three Forks Formation, Sinclair Field and Surrounding Area, Southwestern Manitoba
(core workshop poster)

kreis_et_al_poster_bakken_sk.pdf  (25 MB)
L.K. Kreis, A.L. Costa, and K. Osadetz, 2006: Hydrocarbon Potential of the Bakken Formation, Southwestern Saskatchewan
(core workshop poster)

kreis_et_al_poster_torquay_sk.pdf  (18 MB)
L.K. Kreis, A.L. Costa, and K. Osadetz, 2006: Hydrocarbon Potential of the Torquay Formation, Southwestern Saskatchewan
(core workshop poster)

kreis_et_al_bakken_torquay_presentation_sk.ppt  (47 MB)
L.K. Kreis, A.L. Costa, and K. Osadetz, 2006: Hydrocarbon Potential of the Bakken and Torquay Formations, Southeastern Saskatchewan
(power point presentation)


2006 AAPG International Conference and Exhibition: Reunite Gondwana; Realize the Potential
Perth, Australia
November 8, 2006

Deep Regional Fluid Flow in the North Eastern Flank of the Williston Basin: Implications for Hydrocarbon Migration

Daniele D. Palombi and Benjamin J. Rostron. Department of Earth & Atmospheric Sciences, University of Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3, Canada, phone: 780-492-1115, fax: 780-492-7598, dpalombi@ualberta.ca

The Williston Basin Architecture and Hydrocarbon Potential Project is a collaborative program aimed at developing a geological model of Paleozoic to Mesozoic aged rocks in Eastern Saskatchewan and Manitoba, Canada. Given that the Williston Basin hosts an active groundwater flow system, understanding the hydrogeology is essential because fluid flow in basins can influence the accumulation of exploitable mineral and oil deposits. Thus, a hydrogeological analysis of the entire geologic section has been undertaken to identify driving forces, determine flow directions and rates, and potential hydrocarbon migration pathways and entrapment mechanisms.

Detailed mapping of hydraulic head and water chemistry has been conducted on 19 aquifers ranging in age from the Cambrian to the uppermost Cretaceous. Flow directions determined from maps of equivalent fresh-water hydraulic-head indicate dominantly updip flow of formation waters from SW to NE across the study area. Mapped formation water salinities range in total salinity from 2 to 471 g/L and indicate significant density variations between formations and across the area. Density-dependent fluid flow is important in certain aquifers because downdip flow decreases the upward driving force for cross-formational flow and enhances hydrocarbon trapping capacities. Cross-formational flow associated with the salt dissolution edge of the Prairie Evaporite Formation has resulted in dissolution features in/above Mississippian formations. Vertical migration of fluids from the Devonian promotes upward mixing and thus oil charging of basal Mississippian units (Bakken Formation) along/near the subcrop edges. These hydrogeological results are assisting with new understanding of hydrocarbon migration pathways/plays in the North Eastern portion of the Williston Basin.


13th Williston Basin Petroleum Conference
Regina, Saskatchewan, Canada
April 24-26, 2005
Oral presentation 

Conference link: www.ir.gov.sk.ca/Default.aspx?DN=4025,3383,3384,2936,Documents


Dan Barchyn
Consulting Geologist
62 Deer Lodge Place
Winnipeg, Manitoba, Canada
R3J 2B8

Commercial light oil production from the Bakken formation in Manitoba commenced in 1985 with the discovery of the Bakken A Pool in the Daly Field.  Exploration since then has extended the productive area to the north (Birdtail) and south (Sinclair) defining a productive fairway extending from Twps. 7-16;  Rges. 27-29 W1.  The reservoir unit in the Daly and Birdtail areas is found in a sandstone facies of the Middle Member of the Bakken Formation which was deposited directly on the Torquay unconformity. The main reservoir unit in the Sinclair area is a sandy dolomite in the underlying Torquay (Three Forks) Formation which appears to be in hydraulic communication with the overlying Bakken.  All pools are normally pressured and exhibit production performance indicative of a matrix porosity system without natural fracture enhancement.  The pools discovered to date demonstrate three different play types.  The Daly pools are in an area of ubiquitous oil saturation in the Middle Bakken and productivity is determined by facies variations within this zone.  The Birdtail pools are in an area where a fairly continuous wet Middle Bakken sand is present and trapping occurs in small structural and/or stratigraphic closures.  The Sinclair pools, although early in their development history, appear to be in carbonate beds which are regionally truncated below a major unconformity.  The known distribution of pools and oil shows, both aerially and stratigraphically, raises some interesting questions regarding the nature of the Bakken oil system.  Further research into the hydrodynamic history and the geochemistry of source rocks may address these questions and be useful in determining the direction of future exploration efforts. 

Bakken/Torquay Development: A Manitoba Update – PDF file of original Powerpoint presentation (2.3 MB)


AAPG-CSPG Joint Conference
Calgary, Alberta, Canada
June  19-22, 2005
Oral presentation 

Conference Link: www.aapg.org/calgary/


Melinda Yurkowski
Petroleum Geology Branch, Saskatchewan Ministry of the Economy
Regina, Saskatchewan, Canada

Dr. J.E. Christopher
Consultant, 252 Coldwell Road, Regina, Saskatchewan S4R 4L2

Michelle Nicolas
Petroleum Branch, Manitoba Mineral Resources
Winnipeg, Manitoba, Canada

The Mesozoic strata on the eastern half of Saskatchewan and all of Manitoba consists almost entirely of Cretaceous shales, sandstones and marlstones and of Jurassic quartz arenites, marlstones, carbonates and evaporites.  Sediments were deposited in both marine and non-marine environments that were controlled by both cyclic eustasy and regional tectonics.  Numerous unconformities and variable facies now recognized in the eastern margin of the Western Canada Sedimentary Basin, and recognition of eastern provenances suggest a complex geological setting.  Also, anecdotal and DST evidence of hydrocarbon shows as well as limited production from a small number of pools all point to the need to further the evaluate the hydrocarbon potential of this sparsely tested region.

Saskatchewan Industry and Resources, Manitoba Industry, Economic Development and Mines, Natural Resources Canada and the universities of Alberta and Saskatchewan are participating in a multi-disciplinary project to the architecture of the Phanerozoic subsurface and to assess the hydrocarbon potential of eastern Saskatchewan and western Manitoba.  This two year project was initiated in collaboration under the Geological Survey of Canada Targeted Geoscience Initiative (TGI II) program.  The regional synthesis will provide an integrated geological framework for further assessment of an understudied portion of the Western Canada Sedimentary Basin.  This paper presents a progress report on the Mesozoic component of this study. 

New Perspectives on Hydrocarbon Potential of Bakken and Torquay Formations, Southeastern Saskatchewan

KREIS, L.K., COSTA, A.L. (Saskatchewan Ministry of the Economy, Regina, Saskatchewan) and OSADETZ, K.G. (Geological Survey of Canada, Calgary, Alberta)

Late Devonian to Early Misssissippian Bakken shales in the Williston Basin are believed to have generated and expelled hundreds of billions of barrels of oil, yet only a few tens of millions of barrels have been produced. Recently, horizontal drilling and large sand fracture completions have established significant Bakken production in Richland County, Montana. Careful examination of cores, geophysical logs and production data indicates strong potential for similar horizontal completions, by-passed pay and undiscovered oil in siltstones and sandstones of the middle member of the Bakken in southeastern Saskatchewan. In addition, a large area of anomalously high resistivity response within Bakken shale intervals has been mapped. In this area, Bakken shales appear to have retained a proportion of the generated oil within the formation, which may represent an enormous exploration target. Much of the oil reservoired within the Bakken shale likely resides in a network of enhanced porosity and permeability related to microfractures.  Fracturing is interpreted to be related to hydrocarbon generation, where the combination of the excess pressure (hydrostatic stress) and tectonic stress, particularly that associate with, pre-existing structure, motions on basement faults, salt dissolution and differential compaction during Laramide time may have resulted in a hydraulic fracturing of the Bakken Formation shales, which provides a mechanism for porosity and permeability improvement.

In recent years, dolostones and dolomitic siltstones of the Upper Devonian Torquay Formation, underlying the Bakken Formation, have also proven to be productive for the first time in Saskatchewan in an area along the Saskatchewan-Manitoba border.

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