**Figure 1.** Permian Basin Province in west Texas and southeastern New Mexico. The Permian Basin Province contains the Midland Basin, Delaware Basin, Pecos Basin, Central Basin Platform, Val Verde Basin, Ozona Arch, and the Northwestern, Northern, and Eastern Shelves. 0 50 100 Miles 

### Permian Basin **Province Paleozoic Composite TPS** 

**Northern Shelf**

**Eastern Shelf** 

**Ozona Arch** 

**Val Verde**

**Basin Marathon Fold**  **and Thrust Belt Pecos**  **Basin**

MEXICO NEW MEXICO TEXAS

UNITED STATES **Northwestern Shelf**

**Delaware**

**Basin Central**  **Basin Platform**  **Midland Basin**  99° 100° 101° 102° 104° 105° 106° 103°

34°

33°

32°

31°

30°

**U.S. Department of the Interior U.S. Geological Survey**  **Fact Sheet 2007–3115 February 2008**  Printed on recycled paper 

# National Assessment of Oil and Gas Fact Sheet 

# Assessment of Undiscovered Oil and Gas Resources of the **Permian Basin Province of West Texas and Southeast New Mexico, 2007** 

**Introduction** The U.S. Geological Survey (USGS) recently assessed the undiscovered oil and gas potential of the Permian Basin Province of west Texas and southeast New Mexico (figs. 1, 2). The assessment was geology based and used the total petroleum system (TPS) concept. The geologic elements of a total petroleum system are petroleum source rocks (quality, source rock maturation, generation, and migration), reservoir rocks (sequence stratigraphy, petrophysical properties), and traps (trap formation and timing). Using this geologic framework, the USGS defined a Paleozoic Composite Total Petroleum System and 31 assessment units (AU) within the system, and it quantitatively estimated the undiscovered oil and gas resources within 30 of the assessment units (table 1). This study assessed potential for techni

cally recoverable resources in new field discoveries only; field growth (or reserve growth) of conventional oil and gas fields was not included. Each of the 26 conventional oil and gas assessment units in this study is geologically comparable to one or more oil and gas plays that were defined in the Permian Basin Province by the Bureau of Economic Geology, Texas, and the New Mexico Bureau of Geology and Mineral Resources (Broadhead, 1993; Dutton and others, 2005). Some oil and gas plays were combined to form a single assessment unit. For the first time, the USGS defined continuous (unconventional) assess

ment units in the Permian Basin Province. These units were the (1) Spraberry Continuous Oil AU; (2) Woodford–Barnett Continu

ous Gas AU; (3) Delaware– Pecos Basins Woodford Continuous Shale Gas AU; (4) Delaware–Pecos Basins Barnett Continuous Gas Shale AU; and (5) Delaware Basin Wolfcamp Shale AU.**Figure 2.** Photograph of the Guadalupe Mountains in west Texas illustrating the massive El Capitan carbonate fore-reef facies and the underlying slope-forming Delaware Mountain Group sandstones and mudstones. 

# Resource Summary The USGS assessed undiscovered conventional oil and gas resources and continuous (unconventional) oil and gas resources in 30 assessment units (table 1). For conventional resources, the estimated means were 747 million barrels of oil (MMBO), 5.2 trillion cubic feet of gas (TCFG), and 236 million barrels of natural gas liquids (MMBNGL) in 26 assessment units. For continuous gas resources, the USGS estimated a total mean resource of 34.8 TCFG in three assessment units, which com

prises a mean of 2.8 TCFG in the Woodford–Barnett Continuous Gas AU of the Midland Basin, a mean of 15 TCFG in the Delaware– Pecos Basins Woodford Continuous Shale Gas AU, and a mean of 17 TCFG in the Delaware–Pecos Basins Barnett Continuous Gas Shale AU in the Delaware Basin. The Delaware Basin Wolfcamp Shale AU was not assessed. For continuous oil resources the esti

mated mean was 510 MMBO in the Spraberry Continuous Oil AU in the Midland Basin. The assessment indicates that the majority of undiscovered natural gas in the Permian Basin Province is estimated to be in three continuous assessment units of the Delaware and Midland Basins. Of the total mean of 41 TCFG in the province, about 35 TCFG is estimated to be in these three assessment units. Given that few wells have produced from these assessment units, there is significant geologic uncertainty in these estimates, which is reflected in the range of estimates for natural gas (table 1). 

# For Further Information Supporting geologic studies of the composite total petroleum system and assessment units and the methodology used in the Permian Basin Province assessment are in progress. Assessment results are available at the USGS Central Energy Team website, http://energy.cr.usgs.gov/oilgas/nog a
.**Total Petroleum System (TPS)**  and Assessment Unit (AU) Field Type **Total Undiscovered Resources Oil (MMBO)**  **Gas (BCFG) NGL (MMBNGL)**  **F95 F50**  **F5 Mean**  **F95 F50**  **F5 Mean**  **F95 F50**  **F5 Mean**  **Paleozoic Composite TPS** Ellenberger Group Karst and Dolomite AU **Oil** 12 40 83 43 12 40 90 44 1 3 8 4 **Gas** 147 475 924 498 3 11 24 12 Simpson Group Sandstones AU **Oil** 1 3 6 3 2 6 14 7 0 0 1 0 **Gas** 22 63 123 66 1 2 5 2 Pre-Pennsylvanian Ramp and Platform Carbonates AU **Oil** 15 48 95 51 17 56 122 61 1 4 10 5 **Gas** 91 323 664 343 3 12 28 14 Devonian Thirtyone Formation Chert and Carbonate AU **Oil** 7 22 45 24 23 79 178 87 2 8 19 9 **Gas** 91 321 665 344 5 17 38 19 Lower Pennsylvanian (Morrow/Atoka) Shelf Sandstone and Carbonate AU **Oil** 0 0 0 0 0 0 0 0 0 0 0 0 **Gas** 238 780 1,485 812 3 9 19 10 Pennsylvanian–Lower Permian (Wolfcamp) Northwest Shelf Carbonate AU **Oil** 8 27 56 29 21 72 161 79 1 5 11 5 **Gas** 43 146 308 158 1 4 9 4 Pennsylvanian–Lower Permian (Wolfcamp) Central Basin Plat

form and Shelf Carbonate AU **Oil** 12 40 79 42 43 150 330 164 3 10 24 11 **Gas** 57 183 355 192 3 9 18 9 Pennsylvanian–Lower Permian (Wolfcamp) Horseshoe Plat

form and Eastern Shelf Carbonate and Sandstone AU **Oil** 28 93 175 96 42 143 299 154 5 17 38 18
**Gas** 15 38 69 40 0 1 3 1 Pennsylvanian–Lower Permian (Wolfcamp) Val Verde Slope and Basinal Sandstone and Carbonate AU **Oil** 3 9 22 10 16 56 139 64 1 3 9 4
**Gas** 183 702 1,517 758 8 31 74 35 Pennsylvanian–Lower Permian (Wolfcamp) Slope and Basinal Carbonates AU **Oil** 3 12 27 13 9 32 83 37 0 2 5 2 **Gas** 62 222 481 241 2 9 20 10

Abo Fluvial Sandstones AU **Oil** 0 0 0 0 0 0 0 0 0 0 0 0 **Gas** 0 0 23 8 0 0 0 0 Abo Shelf and Shelf Edge Carbonates AU **Oil** 11 39 83 42 23 83 194 93 2 6 15 7 **Gas** 25 65 123 69 1 2 5 3 Leonardian NW and E Shelf Restricted Platform Carbonates AU **Oil** 22 74 146 78 16 57 125 62 1 4 10 5 **Gas** 0 0 0 0 0 0 0 0
Leonardian Central Basin Plat

form Restricted Carbonates AU **Oil** 10 31 61 33 29 96 209 105 2 7 16 8 **Gas** 13 33 62 35 1 1 3 2 Leonardian Midland Basin Carbonate Sediment Gravity Flow Reservoirs AU **Oil** 28 93 185 98 47 161 355 176 3 10 25 12 **Gas** 0 0 0 0 0 0 0 0 Bone Spring Slope and Basin Reservoirs AU **Oil** 15 50 100 53 55 192 423 210 2 9 21 10 **Gas** 0 0 0 0 0 0 0 0 Spraberry Conventional Sandstones AU **Oil** 5 18 43 20 4 14 36 16 0 1 4 2 **Gas** 0 0 0 0 0 0 0 0 San Andres NW Shelf Platform Carbonates AU **Oil** 2 5 8 5 2 4 8 4 0 0 1 0 **Gas** 0 0 0 0 0 0 0 0 San Andres Eastern Shelf Platform Carbonates AU **Oil** 0 0 3 1 0 0 1 0 0 0 0 0 **Gas** 0 0 0 0 0 0 0 0**Conventional Oil and Gas Resources** [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 accumulations, all liquids are included as NGL (natural gas liquids). F95 represents a 95 percent chance of at least the amount tabulated; other fractiles are defined similarly. TPS, total petroleum system; AU, assessment unit. Gray shading indicates not applicable] 

### Table 1. Permian Basin Province assessment results.**Total Petroleum System (TPS)**  and Assessment Unit (AU) Field Type **Total Undiscovered Resources Oil (MMBO)**  **Gas (BCFG) NGL (MMBNGL)**  **F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean Paleozoic Composite TPS—Continued**  San Andres Central Basin Platform Carbonates AU **Oil** 5 17 33 18 8 25 53 27 1 2 6 3 **Gas** 0 0 0 0 0 0 0 0San Andres–Grayburg Lowstand Carbonates AU **Oil** 3 8 16 9 1 2 5 3 0 0 1 0 **Gas** 0 0 0 0 0 0 0 0San Andres–Grayburg ArtesiaVacuum Trend Carbonates AU **Oil** 0 2 5 2 0 3 8 3 0 0 0 0 **Gas** 0 0 0 0 0 0 0 0 Grayburg Central Basin Platform and Ozona Arch Carbonates AU **Oil** 0 1 3 1 0 0 4 1 0 0 0 0 **Gas** 0 4 21 7 0 0 1 0 Delaware Mountain Group Reservoirs AU **Oil** 18 64 134 69 37 137 314 152 2 6 15 7 **Gas** 8 17 31 18 0 1 1 1
Queen Sandstones AU **Oil** 2 6 11 6 2 6 12 6 0 0 1 0 **Gas** 17 42 73 43 1 1 3 2 Upper Artesia Sandstones and Carbonates AU **Oil** 0 0 3 1 0 0 6 2 0 0 0 0 **Gas** 0 0 20 7 0 0 1 0 **Total Conventional Resources**  

### 747 **5,196 236** 

Delaware-Pecos Basins Woodford Continuous Shale Gas AU **Oil** 0 0 0 0 0 0 0 0 0 0 0 0 **Gas** 10,249 14,741 21,203 15,105 177 289 473 302Delaware-Pecos Basins Barnett Continuous Shale Gas AU **Oil** 0 0 0 0 0 0 0 0 0 0 0 0 **Gas** 1,008 16,437 26,698 17,203 177 322 585 344Midland Basin WoodfordBarnett Continuous Gas AU **Oil** 0 0 0 0 0 0 0 0 0 0 0 0 **Gas** 1,546 2,670 4,613 2,822 55 105 198 113 Delaware Basin Wolfcamp Shale AU **Oil Gas**  Spraberry Continuous Oil AU **Oil** 340 497 725 510 127 240 453 258 11 24 48 26 **Gas** 0 0 0 0 0 0 0 0 **Total Continuous Resources**  

### 510 **35,388 785** 

**Total Undiscovered Oil and Gas Resources**  

### 1,257 **40,584 1,021** **Conventional Oil and Gas Resources Continuous Oil and Gas Resources** 



### Not quantitatively assessed 

### Table 1. Permian Basin Province assessment results.—Continued



# References Broadhead, R.F., 1993, Permian Basin Permian [PB] plays—Overview, in Robertson, J.M., and Broadhead, R.F., eds., Atlas of major Rocky Mountain gas reservoirs: New Mexico Bureau of Mines and Mineral Resources, p. 138–153.Dutton, S.P., Kim, E.M., Broadhead, R.F., Raatz, W.D., Breton, C.L., Ruppel, S.C., and Kerans, C., 2005, Play analysis and leadingedge oil-reservoir development methods in the Permian Basin—Increased recovery through advanced technologies: American Association of Petroleum Geologists Bulletin, v. 89, no. 5, p. 553–576.


# Permian Basin Province Assessment Team Christopher J. Schenk, Richard M. Pollastro, Troy A. Cook, Mark J. Pawlewicz, Timothy R. Klett, Ronald R. Charpentier, and Harry E. Cook.