U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2019–3027

May 2019

National and Global Petroleum Assessment

Assessment of Undiscovered Continuous Tight-Gas

Resources in the Mesaverde Group and Wasatch Formation, 

Uinta-Piceance Province, Utah and Colorado, 2018

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

resources of 24 trillion cubic feet of gas in the Mesaverde Group and Wasatch Formation of the Uinta-Piceance Province in northeast Utah 

and northwest Colorado.

Introduction

The U.S. Geological Survey (USGS) completed a geology-based 

assessment of continuous (unconventional) tight-gas resources of the 

Upper Cretaceous Mesaverde Group and Paleogene Wasatch Formation 

in the Uinta and Piceance Basins of northeast Utah and northwest Colorado 

(fig. 1). The Mesaverde Total Petroleum System (TPS) produces mostly 

natural gas from basin-centered accumulations in the two basins. The 

main sources are primarily coal and carbonaceous shale and siltstone in 

the Mesaverde Group. This assessment is based on the TPS concept and 

related geologic criteria and includes information on the hydrocarbon 

source rocks, reservoir rocks, and hydrocarbon traps. In this study, we 

defined the Mesaverde TPS and two continuous assessment units (AUs) 

that have similar structural, stratigraphic, and petroleum-charge histories. 

The assessment input data for each AU are shown in table 1. 

Total Petroleum System

The Mesaverde TPS extends across the Uinta and Piceance Basins 

of northeast Utah and northwest Colorado (fig. 1) and consists of a mix 

of lithologies (sandstone, mudstone, and coal) associated with fluvial, 

flood plain, coastal plain, and nearshore marine depositional settings. 

In the Uinta Basin, the Mesaverde TPS includes the Mesaverde Group 

(Blackhawk Formation, Castlegate Sandstone, and Price River Formation) 

and the Wasatch Formation. In the Piceance Basin, the Mesaverde TPS 

includes the Williams Fork Formation of the Mesaverde Group and 

the overlying Wasatch Formation (Johnson and Roberts, 2003). The 

primary petroleum source rocks in the Uinta Basin are bituminous coals 

within the Blackhawk and Neslen Formations of the Mesaverde Group; 

the major source rocks in the Piceance Basin are the Cameo-Fairfield 

coal and carbonaceous shale deposits within the Williams Fork Formation 

(Johnson and Roberts, 2003). The Mesaverde TPS is mostly self-sourced 

with total organic carbon ranging from 10 to 70 weight percent in the 

Cameo-Fairfield coal (Nelson, 2003). The underlying Mancos Shale 

may also be an additional source of natural gas. Geochemical evidence 

from the Mamm Creek field in the Piceance Basin suggests that the field 

has more than one source of gas. The gas produced from the west side 

of the field is mostly intraformational coal gas, whereas the gas from the 

northeastern part of the field has a marine shale source, most likely the 

Mancos Shale (Lillis and others, 2008). 

Assessment Units

Two AUs are identified in this assessment: the Uinta Mesaverde 

Tight Gas AU and the Piceance Mesaverde Tight Gas AU. The Uinta 

Mesaverde Tight Gas AU lies within the Uinta Basin part of the 

Uinta-Piceance Province (Johnson and Roberts, 2003) in northeast Utah 

and covers a maximum area of 4,088,000 acres (fig. 1). The potential 

AU resource boundary includes the areas where the Mesaverde Group 

source rock is thermally mature with vitrinite reflectance (Ro

) values of 

0.75 percent or greater and includes the “transitional gas” AU boundaries, 

as defined in Johnson and Roberts (2003). Tight gas from the 

Mesaverde Group and Wasatch Formation has been produced—more 

than 1.76 trillion cubic feet of gas (TCF)—from over 3,000 wells in the 

Uinta Basin, mostly from the Natural Buttes gas field in the eastern part 

of the basin (IHS MarkitTM, 2017). 

The Piceance Mesaverde Tight Gas AU lies within the Piceance 

Basin part of the Uinta-Piceance Province in northwest Colorado 

(fig. 1). Mesaverde Group and Wasatch Formation tight gas—more than 

7.7 TCF—has been produced from over 12,000 wells in the Piceance 

Basin, mostly from the central part of the basin (IHS Markit, 2017). 

Vernal

Glenwood

Springs Douglas Creek Arch

COLORADO

UTAH

WYOMING

0 40 80 KILOMETERS

0 40 80 MILES

EXPLANATION

Uinta-Piceance Province boundary 

Piceance Mesaverde Tight Gas AU

Mesaverde Total Petroleum System 

Mamm Creek field

Uinta Mesaverde Tight Gas AU

Greater Natural Buttes (GNB) field—Includes

Natural Buttes, Buck Canyon, Rock House, 

 Island, and Oil Springs gas fields

112° 111° 110° 109° 108° 107°

41°

40°

39°

38°

UT CO

WY

AZ NM

ID

NV

NE

TX

SD

KS

CA

OK

Map

area

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

Figure 1. Location of the Uinta-Piceance Province, Utah and Colorado, 

with continuous assessment unit (AU) boundaries. 
Undiscovered Resources Summary

Using the USGS continuous resource methodology for assessing 

petroleum resources (Charpentier and Cook, 2011), we quantitatively 

assessed Mesaverde Group and Wasatch Formation tight-gas resources 

in two continuous (unconventional) AUs in the Uinta-Piceance 

Province (table 2). The overall total mean resources in the Uinta 

Mesaverde Tight Gas and the Piceance Mesaverde Tight Gas AUs are 

24,033 billion cubic feet of gas (BCFG), or 24 TCF of gas, with an 

F95–F5 range from 6,750 to 46,469 BCFG and 96 million barrels of natural 

gas liquids (MMBNGL) with an F95–F5 range from 25 to 197 MMBNGL.

For the Uinta Mesaverde Tight Gas AU, the total mean resources 

are 19,325 BCFG, or 19.3 TCF of gas, with an F95–F5 range from 5,481 

to 37,113 BCFG and 77 MMBNGL with an F95–F5 range from 20 to 158 

MMBNGL. For the Piceance Mesaverde Tight Gas AU, the total mean 

resources are 4,708 BCFG, or 4.7 TCF of gas, with an F95–F5 range from 

1,269 to 9,356 BCFG and 19 MMBNGL with an F95–F5 range from 

5 to 39 MMBNGL.

Table 1. Key input data for two continuous tight-gas assessment units in the Uinta-Piceance Province, Utah and Colorado.

[AU, assessment unit; %, percent; EUR, estimated ultimate recovery per well; BCFG, billion cubic feet of gas. The average EUR input is the minimum, median, 

maximum, and calculated mean. Shading indicates not applicable]

Assessment input data—

Continuous AUs

Uinta Mesaverde Tight Gas AU Piceance Mesaverde Tight Gas AU

Minimum Mode Maximum Calculated 

mean

Minimum Mode Maximum Calculated 

mean

Potential production area of AU (acres) 1,200 2,050,000 4,088,000 2,046,400 1,300 1,273,000 1,896,000 1,056,767

Average drainage area of wells (acres) 30 60 90 60 30 60 90 60

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

Untested area in AU (%) 85 90 95 90 20 40 60 40

Average EUR (BCFG) 0.2 0.85 1.7 0.883 0.2 0.9 1.9 0.941

AU probability 1.0 1.0

Table 2. Results for two continuous tight-gas assessment units in the Uinta-Piceance Province, Utah and Colorado.

[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

Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean

Mesaverde Total Petroleum System

Uinta Mesaverde Tight Gas AU 1.0 Gas 5,481 18,144 37,113 19,325 20 70 158 77

Piceance Mesaverde Tight Gas AU 1.0 Gas 1,269 4,353 9,356 4,708 5 17 39 19

Total undiscovered continuous 

resources

6,750 22,497 46,469 24,033 25 87 197 96

References Cited

Charpentier, R.R., and Cook, T.A., 2011, USGS methodology for 

assessing continuous petroleum resources: U.S. Geological Survey 

Open-File Report 2011–1167, 73 p., accessed April 4, 2017, at 

https://pubs.usgs.gov/of/2011/1167.

IHS MarkitTM, 2017, U.S. well history and production database: 

Englewood, Colo., IHS Markit, accessed January 2017 at https://

www.ihsenergy.com. [Available from IHS Markit, 15 Inverness Way 

East, Englewood, CO 80112.] 

Johnson, R.C., and Roberts, S.B., 2003, The Mesaverde Total Petroleum 

System, Uinta-Piceance Province, Utah and Colorado, chap. 7 of 

USGS Uinta-Piceance Assessment Team, Petroleum systems and 

geologic assessment of oil and gas in the Uinta-Piceance Province, 

Utah and Colorado: U.S. Geological Survey Digital Data Series 

DDS–69–B, ver. 1.0, 68 p., accessed January 2018 at https://pubs.

usgs.gov/dds/dds-069/dds-069-b/REPORTS/Chapter_7.pdf. 

Lillis, P.G., Ellis, G.S., Dempsey, M.P., and Cumella, S.P., 2008, 

Origin of gas in the Mamm Creek field, Piceance Basin, Colorado, 

in American Association of Petroleum Geologists meeting, Denver, 

Colo., July 9–11, 2008, Proceedings: American Association of 

Petroleum Geologists. 

Nelson, P.H., 2003, A review of the Multiwell Experiment, Williams 

Fork and Iles Formations, Garfield County, Colorado, chap. 15 of 

USGS Uinta-Piceance Assessment Team, Petroleum systems and 

geologic assessment of oil and gas in the Uinta-Piceance Province, Utah 

and Colorado: U.S. Geological Survey Digital Data Series DDS–69–B, 

ver. 1.0, 28 p., accessed January 2018 at https://pubs.usgs.gov/dds/

dds-069/dds-069-b/REPORTS/Chapter_15.pdf.

Mesaverde Group Tight-Gas Assessment Team

Ronald M. Drake II, Christopher J. Schenk, Tracey J. Mercier, 

Phuong A. Le, Thomas M. Finn, Ronald C. Johnson, 

Cheryl A. Woodall, Stephanie B. Gaswirth, Kristen R. Marra, 

Janet K. Pitman, Heidi M. Leathers-Miller, Seth S. Haines, 

and Marilyn E. Tennyson

For More Information

Assessment results are also available at the USGS 

Energy Resources Science Center website at 

https://energy.usgs.gov. 

ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20193027