U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet FS-157-02 (Supercedes USGS Fact Sheet FS-026-02)

February 2003 Printed on recycled paper

Printed on recycled paper

Introduction

The U.S. Geological Survey (USGS) recently completed an 

assessment of the undiscovered oil and gas potential of the UintaPiceance Province of northwestern Colorado and northeastern Utah 

(fig. 1). The assessment of the Uinta-Piceance Province is geology 

based and uses the Total Petroleum System concept. The geologic 

elements of Total Petroleum Systems include hydrocarbon source 

rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy, petrophysical properties), and hydrocarbon traps (trap formation and timing). Using this 

geologic framework, the USGS defined five Total Petroleum Systems 

and 20 Assessment Units within these Total Petroleum Systems, and 

quantitatively estimated the undiscovered oil and gas resources within 

each Assessment Unit (table 1).

Resource Summary

The USGS assessed undiscovered conventional oil and gas and 

continuous (unconventional) oil and gas, including coal-bed gas 

(CBG in table 1). The USGS estimated a mean of 21 trillion cubic 

feet of gas (TCFG), a mean of 60 million barrels of oil (MMBO), 

and a mean of 43 million barrels of natural gas liquids (MMBNGL) 

in five Total Petroleum Systems. Nearly all of the undiscovered 

gas resource is continuous (unconventional) rather than conventional. 

Of the 21 TCFG, 13 TCFG is estimated to be in the Mesaverde 

Total Petroleum System, and 7 TCFG is in the Mancos/Mowry Total 

Petroleum System. The Ferron/Wasatch Plateau Total Petroleum 

System and Mesaverde Total Petroleum System are estimated to 

contain 2.3 TCFG of coal-bed gas. The Phosphoria and Green River 

Total Petroleum Systems contain the balance of the undiscovered 

gas resource.

For Further Information

Supporting geologic studies of Total Petroleum Systems 

and Assessment Units, and the methodology used in the UintaPiceance Province assessment are in progress. Assessment 

results are available at the USGS Central Energy Team website:

 http://energy.cr.usgs.gov/oilgas/noga/

Uinta-Piceance Assessment Team 

Mark A. Kirschbaum (Task Leader; mkirsch@usgs.gov); Larry 

Anna, Timothy S. Collett, Troy Cook, Russell F. Dubiel, Thomas 

M. Finn, Robert D. Hettinger, Mitchell Henry, Edward A. Johnson, 

Ronald C. Johnson, Paul G. Lillis, Philip H. Nelson, Vito F. Nuccio, 

Cynthia A. Rice, Laura N.R. Roberts, and Stephen B. Roberts.

National Assessment of Oil and Gas Fact Sheet

Assessment of Undiscovered Oil and Gas Resources of 

the Uinta-Piceance Province of Colorado and Utah, 2002

Using a geologybased assessment 

methodology, the U.S. 

Geological Survey 

estimates a mean of 

21 trillion cubic feet of 

undiscovered natural 

gas and a mean of 

60 million barrels of 

undiscovered oil in 

the Uinta-Piceance 

Province. Nearly all 

of the undiscovered 

gas resource is 

unconventional 

(continuous).

Figure 1. Uinta-Piceance Province located in northwestern Colorado and northeastern Utah. The Douglas Creek arch separates 

Piceance Basin from Uinta Basin. The Wasatch Plateau is included in this province.
Table 1. Uinta-Piceance Province Assessment Results.

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

estimates. For gas fields, all liquids are included under the NGL (natural gas liquids) category. Undiscovered gas resources are the sum of 

non-associated and associated gas. 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. Gray shade indicates not applicable. CBG is coal-bed gas]