National and Global Petroleum Assessment

Assessment of Continuous Oil and Gas Resources in the Duvernay 

Formation, Alberta Basin Province, Canada, 2018

Introduction

The U.S. Geological Survey (USGS) quantitatively assessed 

the potential for undiscovered, technically recoverable continuous 

(unconventional) oil and gas resources in the Late Devonian Duvernay 

Formation of the Alberta Basin Province in Canada (fig. 1). The 

Duvernay Formation represents transgressive basinal shales deposited in oxygen-deficient, relatively shallow (100 meters or less) water 

adjacent to similar-age carbonate platform and fringing reefs of the 

Leduc Formation (Dunn and Humenjuk, 2014; Fothergill and others, 

2014). In the Late Devonian, carbonate platforms and adjacent basins 

were located along the passive western margin of North America with 

open-marine conditions to the west. From the Carboniferous through the 

Triassic, subduction and collision of several terranes along the western 

margin of North America resulted in a long period of uplift, erosion, or 

nondeposition. The formation of an east-verging fold and thrust belt and 

foreland basin in the Late Jurassic and its continued development into 

the Late Cretaceous through Paleogene provided the necessary burial 

for adequate thermal maturity for oil and gas generation (Fowler and 

others, 2001). Since the Eocene, the basin has uplifted and eroded.

Total Petroleum System and Assessment Units

The USGS defined a Duvernay Total Petroleum System (TPS) and

assessed potential continuous oil and gas resources within this TPS. The

Duvernay Formation consists of dark, bituminous, organic-rich lime

mudstones that form an important petroleum source rock for conventional oil and gas accumulations (Switzer and others, 1994). Shales of the

Duvernay Formation contain Type II organic matter, have organic carbon

contents of as much as 20 weight percent, have hydrogen index values of

as much as 600 milligrams of hydrocarbon per gram of organic carbon,

are overpressured (up to 0.84 pounds per square inch per foot), and can

be as much as 70 meters thick (Fowler and others, 2001; Chen and Jiang,

2016; Davis and others, 2016). Duvernay Formation oils are generally

low in sulfur (less than 0.5 percent), but gas from the Duvernay Formation can contain several percent of hydrogen sulfide (Van de Wetering and

others, 2015). Thermal maturity maps show that shales in the eastern part

of the basin are thermally immature, but shales in the western part are

thermally mature for oil and gas generation (Stoakes and Creaney, 1984).

Burial in the foreland basin during the Late Cretaceous through Paleogene

was sufficient to have thermally matured organic matter in these shales

(Fowler and others, 2001; Machel and others, 2012).

The geologic model for the Duvernay TPS is for oil and gas to have

been generated from Late Devonian source rocks primarily because of

Late Cretaceous–Paleogene foredeep burial. Oil and gas were partially

retained within the Duvernay Formation shales following generation and

migration of oil and gas into conventional carbonate traps. For this study,

the Duvernay Shale Oil Assessment Unit (AU) and North Duvernay Shale

Oil AU were defined to encompass areas of shale within the oil-generation

window, and the Duvernay Shale Gas AU was defined to include the

area potentially within the gas-generation window. Uncertainty in the

assessment is related to the thermal maturity boundaries as mapped and to 

the retention of oil and gas within Duvernay Formation shales.

Assessment input data are summarized in table 1. Input data for 

drainage areas, success ratios, and estimated ultimate recoveries are 

guided by geologic analogs in the United States.

Undiscovered Resources Summary

The USGS quantitatively assessed continuous oil and gas 

resources in three assessment units (table 2) in the Duvernay 

Formation of the Alberta Basin Province, Canada. For undiscovered, 

technically recoverable continuous oil and gas resources, the 

estimated mean cumulative resources are 1,347 million barrels of oil 

(MMBO), or 1.3 billion barrels of oil, with an F95–F5 fractile range 

from 303 to 2,946 MMBO; 22,238 billion cubic feet of gas (BCFG), 

or 22.2 trillion cubic feet of gas (TCFG), with an F95–F5 fractile 

range from 5,196 to 47,154 BCFG; and 874 million barrels of natural 

gas liquids (MMBNGL) with an F95–F5 fractile range from 190 to 

1,947 MMBNGL.

Figure 1. Map showing the three

continuous assessment units (AUs) in the 

Duvernay Formation of the Alberta Basin 

Province, Canada. Province boundary is 

from Klett and others, 1997.

ALBERTA

BRITISH

COLUMBIA

SASKATCHEWAN

MANITOBA

NORTHWEST

TERRITORIES

NUNAVUT

YUKON

PACIFIC

OCEAN

Base map from U.S. Department of the Interior National Park Service

UNITED STATES

CANADA

132° W 124° W 116° W 108° W 100° W 92° W

58° N

50° N

0 100 200 MILES

0 200 KILOMETERS 100

EXPLANATION

Duvernay Shale Oil AU

Alberta Basin Province boundary

North Duvernay Shale Oil AU

Duvernay Shale Gas AU

Alberta Basin Province

boundary is shown in plum.

CANADA

UNITED

STATES

UNITED

STATES

RUSSIA

PACIFIC

OCEAN

UNITED STATES

CANADA

Map

area

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2018–3065

January 2019

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of

1.3 billion barrels of oil and 22.2 trillion cubic feet of gas in the Duvernay Formation of the Alberta Basin Province, Canada.
For More Information

Assessment results are also available at the USGS Energy Resources Program website at https://energy.usgs.gov.

Duvernay Formation Assessment Team 

Christopher J. Schenk, Tracey J. Mercier, Marilyn E. Tennyson, Phuong A. Le, Michael E. Brownfield, Kristen R. Marra, Stephanie B. Gaswirth, 

Heidi M. Leathers-Miller, and Ronald M. Drake II

References Cited

Chen, Z., and Jiang, C., 2016, A revised method for organic porosity estimation in 

shale reservoirs using Rock-Eval data—Example from Duvernay Formation in the 

Western Canada Sedimentary Basin: American Association of Petroleum Geologists Bulletin, v. 100, no. 3, p. 405–422.

Davis, M., Karlen, G., Tobey, M., and Tivey, D., 2016, Insights into the evolution of 

an intracratonic foreland basin—A regional assessment of the Duvernay Formation, 

chap. 4 of Dolan, M.P., Higley, D.K., and Lillis, P.G., eds., Hydrocarbon source 

rocks in unconventional plays, Rocky Mountain region: The Rocky Mountain 

Association of Geologists, p. 137–171.

Dunn, L.A., and Humenjuk, J., 2014, The Duvernay Formation—Integrating 

sedimentology, sequence stratigraphy and geophysics to identify sweet spots in 

a liquids-rich shale play, Kaybob Alberta, in Unconventional Resources Technology Conference, Denver, Colo., August 25–27, 2014, Proceedings: Society of 

Exploration Geophysicists, American Association of Petroleum Geologists, Society 

of Petroleum Engineers, URTeC 19-22713-MS, 7 p., accessed June 26, 2018, at 

https://www.onepetro.org/conference-paper/URTEC-1922713-MS.

Fothergill, P., Boskovic, D., Schoellkopf, N., Murphy, P., and Mukati, M.A., 2014, 

Regional modelling of the Late Devonian Duvernay Formation, Western Alberta, 

Canada, in Unconventional Resources Technology Conference, Denver, Colo., 

August 25–27, 2014, Proceedings: Society of Exploration Geophysicists, 

American Association of Petroleum Geologists, Society of Petroleum Engineers, 

URTeC 1923935-MS, 8 p., accessed June 26, 2018, at https://www.onepetro.org/

conference-paper/URTEC-1923935-MS.

Fowler, M.G., Stasiuk, L.D., Hearn, M., and Obermajer, M., 2001, Devonian hydrocarbon 

source rocks and their derived oils in the Western Canada Sedimentary Basin: Bulletin 

of Canadian Petroleum Geology, v. 49, no. 1, p. 117–148.

Klett, T.R., Ahlbrandt, T.S., Schmoker, J.W., and Dolton, G.L., 1997, Ranking of the 

world’s oil and gas provinces by known petroleum volumes: U.S. Geological Survey 

Open-File Report 97–463, 1 CD–ROM. [Also available at https://pubs.usgs.gov/

of/1997/ofr-97-463/97463.html.]

Machel, H.G., Borrero, M.L., Dembicki, E., Huebscher, H., Ping, L., and Zhao, Y., 2012, 

The Grosmont—The world’s largest unconventional oil reservoir hosted in carbonate 

rocks, in Garland, J., Neilson, J.E., Laubach, S.E., and Whidden, K.J., eds., Advances 

in carbonate exploration and reservoir analysis: The Geological Society of London, 

Special Publication No. 370, p. 49–81.

Stoakes, F.A., and Creaney, S., 1984, Sedimentology of a carbonate source rock—The 

Duvernay Formation of Central Alberta, in Uliak, L., ed., Carbonates in subsurface 

and outcrop—Proceedings of the 1984 C.S.P.G. Core Conference, Calgary, 

Alberta, Canada, October 18–19, 1984: Canadian Society of Petroleum Geologists 

(C.S.P.G.), p. 132–147.

Van de Wetering, A., Mayer, B., and Sanei, H., 2015, Chemostratigraphic associations 

between trace elements and organic parameters within the Duvernay Formation, 

Western Canada Sedimentary Basin, in Unconventional Resources Technology 

Conference, San Antonio, Tex., July 20–22, 2015, Proceedings: Society of 

Exploration Geophysicists, American Association of Petroleum Geologists, Society 

of Petroleum Engineers, URTeC 2153955, 11 p., accessed June 26, 2018, at 

http://archives.datapages.com/data/urtec/2015/2153955.pdf.

Table 1. Key input data for three continuous assessment units (AUs) in the Duvernay Formation of the Alberta Basin Province, Canada.

[AU, assessment unit; %, percent; EUR, estimated ultimate recovery per well; MMBO, million barrels of oil; BCFG, billion cubic feet of gas; Well drainage area, 

success ratio, and EUR are defined partly using U.S. shale-oil and shale-gas analogs. The average EUR input is the minimum, median, maximum, and calculated mean. 

Shading indicates not applicable]

Assessment input data—Continuous AUs

Duvernay Shale Oil AU North Duvernay Shale Oil AU

Minimum Mode Maximum Calculated 

mean Minimum Mode Maximum Calculated 

mean

Potential production area of AU (acres) 1,000 3,230,000 6,460,000 3,230,333 1,000 2,634,500 5,269,000 2,634,833

Average drainage area of wells (acres) 120 180 240 180 120 180 240 180

Success ratio (%) 10 70 90 56.7 10 50 90 50

Average EUR (MMBO) 0.03 0.08 0.2 0.086 0.02 0.06 0.15 0.064

AU probability 1.0 1.0

Assessment input data—Continuous AU

Duvernay Shale Gas AU

Minimum Mode Maximum Calculated 

mean

Potential production area of AU (acres) 1,000 4,185,000 8,214,000 4,133,333

Average drainage area of wells (acres) 80 120 160 120

Success ratio (%) 10 70 90 56.7

Average EUR (BCFG) 0.1 1 2 1.036

AU probability 1.0

Table 2. Results for three continuous assessment units (AUs) in the Duvernay Formation of the Alberta Basin Province, Canada.

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; NGL, natural gas liquids; MMBNGL, million barrels of natural gas liquids. Results shown are fully risked 

estimates. F95 represents a 95-percent chance of at least the amount tabulated; other fractiles are defined similarly. Fractiles are additive under the assumption of perfect 

positive correlation. Shading indicates not applicable]

Total petroleum system 

and assessment units (AUs)

AU

probability

Accumulation

type

Total undiscovered resources

Oil (MMBO) Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

Duvernay Total Petroleum System

Duvernay Shale Oil AU 1.0 Oil 198 776 1,901 876 289 1,149 2,903 1,313 11 45 121 52

North Duvernay Shale Oil AU 1.0 Oil 105 409 1,045 471 152 607 1,590 706 3 12 33 14

Duvernay Shale Gas AU 1.0 Gas 4,755 18,254 42,661 20,219 176 707 1,793 808

Total undiscovered continuous resources 303 1,185 2,946 1,347 5,196 20,010 47,154 22,238 190 764 1,947 874

ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20183065