Figure 1. Location of geologic provinces

considered in this study.

Figure 2. Stratigraphic column of northeast Mexico 

and southeast Texas. The Pimienta Formation of the 

Tampico-Misantla Basin is equivalent to the La Casita 

Formation of the Burgos Basin. The Eagle Ford Formation of south Texas is partly equivalent to the Agua Nueva Formation of northeast Mexico (Peterson, 1985). [Gp., 

Group; Fm., Formation; Cgl., conglomerate; Ls., limestone; 

Sh., shale; Evap., evaporite] 

Figure 3. Schematic diagram showing

geologic parameters for potential assessed

areas. R

o

, vitrinite reflectance, in percent.

Figure 5. Map showing the total organic 

carbon (TOC) data greater than 2 weightpercent for Type II marine Tithonian shale 

in the onshore part of the TampicoMisantla Basin. Values of TOC greater 

than 2 weight-percent define areas in this 

study that pass the threshold for quantitative assessment. Note that much of 

the Tithonian shale in this basin contains 

less than 2 weight-percent TOC. Of the 

area greater than 1 weight-percent, 21 

percent is greater than 2 weight-percent 

TOC. This value of 21 percent was used 

to characterize Tithonian shales in the 

Burgos and Sabinas Basins as the map 

available for those basins only illustrated 

rock with greater than 1 weight-percent 

TOC (data from PEMEX, 2012).

Figure 7. Map showing the intersection 

of figures 5 and 6, and represents the 

resultant area with both greater than 2 

weight-percent total organic carbon and 

adequate thermal maturity for oil and gas 

generation. The green area defines the 

modal area of the Tithonian Shale Oil 

Assessment Unit (AU), and the red area 

defines the modal area of the Tithonian 

Shale Gas AU. Both AUs were quantitatively assessed in this study.

Figure 12. Map showing the outline 

of potential shale-oil area (1,100,000 

acres) in the Agua Nueva Formation 

with greater than 1 weight-percent 

total organic carbon (TOC) by PEMEX 

(2012) in the Burgos Basin. For the U.S. 

Geological Survey assessment, the 

potential area at the mode is 704,000 

acres (table 1), which is the total area 

(1,100,000 acres) multiplied by the Tampico-Misantla Basin analog area in the 

Aqua Nueva Formation with greater 

than 2 weight-percent TOC (64 percent).

Figure 14. Map showing the outline of potential shale-gas area (3,941,000 acres) in 

the La Casita Formation with greater than 1 

weight-percent total organic carbon (TOC) 

by PEMEX (2012) in the Burgos Basin. For 

the U.S. Geological Survey assessment, the 

potential area at the mode is 828,000 acres 

(table 1), which is the total area (3,941,000 

acres) multiplied by the Tampico-Misantla 

Basin analog area in the Pimienta Formation with greater than 2 weight-percent 

TOC (21 percent).

Figure 16. Map showing the extent of 

Olmos Formation coals in the Burgos 

Basin, as mapped by Warwick (2007). 

The coals define the extent of the Rio 

Escondido Olmos Coalbed Gas Assessment Unit (AU).

Figure 13. Map showing the outline of 

potential shale-gas area (3,530,000 acres) 

in the Agua Nueva Formation with greater than 1 weight-percent total organic 

carbon (TOC) by PEMEX (2012) in the 

Burgos Basin. For the U.S. Geological 

Survey assessment, the potential area 

at the mode is 2,259,000 acres (table 1), 

which is the total area (3,530,000 acres) 

multiplied by the Tampico-Misantla Basin 

analog area in the Aqua Nueva Formation with greater than 2 weight-percent 

TOC (64 percent).

Figure 15. Map showing the extent 

of the Wilcox-Lobo Tight Gas Assessment Unit (AU) in the Burgos Basin. This 

mapped area is an extension of a much 

larger Wilcox-Lobo AU in the United 

States. Sandstones of the Wilcox-Lobo 

stratigraphic interval are part of a large 

disrupted zone with slide blocks and related deformational features within which 

are the Wilcox-Lobo low-permeability 

(tight) gas sandstone reservoirs.

Figure 17. Map showing the outline of 

potential shale-gas area (3,667,000 acres) 

in the Agua Nueva Formation with greater 

than 1 weight-percent total organic carbon (TOC) by PEMEX (2012) in the Sabinas 

Basin. For the U.S. Geological Survey assessment, the potential area at the mode 

is 704,000 acres (table 1), which is the 

total area (3,667,000 acres) multiplied by 

the Tampico-Misantla Basin analog area 

in the Aqua Nueva Formation with greater 

than 2 weight-percent TOC (64 percent), 

and then multiplied by 30 percent for the 

effects of structural complexity on the 

retention of gas.

Figure 18. Map showing the outline of 

potential shale-gas area (8,961,000 acres) 

in the La Casita Formation with greater 

than 1 weight-percent total organic carbon (TOC) by PEMEX (2012) in the Sabinas 

Basin. For the U.S. Geological Survey assessment, the potential area at the mode 

is 565,000 acres (table 1), which is the 

total area (8,961,000 acres) multiplied by 

the Tampico-Misantla Basin analog area 

in the Pimienta Formation withgreater 

than 2 weight-percent TOC (21 percent), 

and then multiplied by 30 percent for the 

effects of structural complexity on the 

retention of gas.

Figure 11. Map showing the intersection of 

figures 9 and 10, and presents the resultant 

area with greater than 2 weight-percent 

total organic carbon and adequate thermal 

maturity for oil and gas generation. The 

green area defines the modal area of the 

Turonian Agua Nueva Shale Oil Assessment 

Unit (AU), and the red areas define the modal area of the Turonian Agua Nueva Shale 

Gas AU. Both AUs were quantitatively assessed in this study.

Figure 4. Map showing the area of 

the Tampico-Misantla Basin with 

greater than 1 weight-percent total 

organic carbon (TOC) within Tithonian 

marine shales. About 21 percent 

of the area with TOC greater than 

1 weight-percent is characterized by 

values greater than 2 weight-percent 

TOC (data from PEMEX, 2012). 

Figure 8. Map showing only the area of 

the Tampico-Misantla Basin with 

greater than 1 weight-percent total 

organic carbon (TOC) within Turonian 

marine shales. About 64 percent of 

the area with TOC greater than 1 

weight-percent is characterized by values greater than 2 weight-percent TOC 

(data from PEMEX, 2012). 

Figure 6. Map showing the extent of 

thermally mature Tithonian shale in the 

onshore part of the Tampico-Misantla 

Basin. Maturity data were categorized 

by Tmax values from Rock-Eval analyses. T

max values greater than 465 °C defined the area of source rock thermally 

mature for gas (red area); Tmax values 

between 435 and 465 °C defined the 

oil maturity window (green area), and 

values less than 435 °C were defined as 

thermally immature for Type II kerogen. 

The boundaries on this map as derived 

from T

max values are uncertain (data 

from PEMEX, 2012).

Figure 10. Map showing the extent of 

thermally mature Turonian shale in the 

onshore part of the Tampico-Misantla 

Basin. Maturity data were categorized 

by Tmax values from Rock-Eval analyses. T

max values greater than 465 °C 

defined the area of source rock thermally mature for gas (red areas); Tmax

values between 435 and 465 °C defined 

the oil maturity window (green area), 

and values less than 435 °C were thermally immature for Type II kerogen. The 

boundaries on this map as derived from 

T

max data are uncertain (data from 

PEMEX, 2012).

Figure 9. Map showing the total organic 

carbon (TOC) data greater than 2 weightpercent for Type II marine Turonian shale 

in the onshore part of the TampicoMisantla Basin. Values of TOC greater 

than 2 weight-percent define areas in this 

study that exceed the threshold for quantitative assessment. Of the area greater 

than 1 weight-percent TOC, 64 percent is 

greater than 2 weight-percent TOC. This 

value of 64 percent was used to characterize the Turonian shales in the Burgos 

and Sabinas Basins as the map available 

for those basins only illustrated rock with 

greater than 1 weight-percent TOC (data 

from PEMEX, 2012).

EXPLANATION

Ro > 0.6 < 1.3%

Ro > 1.3%

Total Organic Carbon > 2 weight-percent

Total Organic Carbon 1 to 2 weight-percent

Total Organic Carbon

1–2 weight-percent

 (Not Assessed)

Total Organic Carbon

> 2 weight-percent

 (Assessed)

Oil

0.6 – 1.3 %

Ro

Gas

> 1.3 %

Ro

Ro < 1.3% Ro > 1.3%

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO

MEXICO

Taumaulipas Arch

Magiscatzin Basin

S I E R R A

M A D R E

O R I E N TA L

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

Tithonian Organic Richness

> 2 weight-percent TOC

EXPLANATION

Geologic province 

 boundaries

130°0'0"W 120°0'0"W 110°0'0"W 100°0'0"W 90°0'0"W 80°0'0"W 70°0'0"W 60°0'0"W

0 650 1,300 2,600 Kilometers

Eagleford Gas

Eagleford Oil

Smackover

Land

0 325 650 1,300 Miles

UNITED STATES

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

MEXICO

Burgos

Basin

Province

Veracruz

Basin

Province

Tampico–Misantla

Basin Province

TITHONIAN

TOC

> 2 WEIGHT -

PERCENT

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO S I E R R A

M A D R E

O R I E N TA L

MEXICO

Taumaulipas Arch

Magiscatzin Basin

Burgos

Basin

Province

Veracruz

Basin

Province

Tampico–Misantla

Basin Province

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

Tithonian Assessment Units

Pimienta Shale Oil AU

Pimienta Shale Gas AU

EXPLANATION

Geologic province 

 boundaries

UNITED STATES

MEXICO

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

TITHONIAN

FINAL

AU MAP

102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

USA

MEXICO

Agua Nueva Shale Oil AU

0 70 MILES

0 70 KILOMETERS

EXPLANATION

Burgos

Basin

Province

Agua Nueva

Shale Oil

53000461

Sabinas

Basin

Province

TURONIAN

102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

USA

MEXICO

Agua Nueva Shale Gas AU

0 70 MILES

0 70 KILOMETERS

EXPLANATION

Burgos

Basin

Province

Agua Nueva

Shale Gas

53000462

Sabinas

Basin

Province

TURONIAN

103° 102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

23° La Casita Shale Gas AU

0 80 MILES

0 80 KILOMETERS

EXPLANATION

USA

MEXICO

Burgos

Basin

Province

La Casita

Shale Gas

53000361

TITHONIAN

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO S I E R R A

M A D R E

O R I E N TA L

MEXICO

Taumaulipas Arch

Magiscatzin Basin

Burgos

Basin

Province

Veracruz

Basin

Province

Tampico–Misantla

Basin Province

Turonian Organic Richness

Taumaulipas Arch

Magiscatzin Basin

> 2 weight-percent TOC

EXPLANATION

Geologic province 

 boundaries

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

130°0'0"W 120°0'0"W 110°0'0"W 100°0'0"W 90°0'0"W 80°0'0"W 70°0'0"W 60°0'0"W

UNITED STATES

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

MEXICO

TURONIAN

TOC

> 2 WEIGHTPERCENT

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO S I E R R A

M A D R E

O R I E N TA L

MEXICO

Taumaulipas Arch

Magiscatzin Basin

Burgos

Basin

Province

Veracruz

Basin

Province

Tampico–Misantla

Basin Province

Turonian Assessment Units

EXPLANATION

Geologic province 

 boundaries

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

UNITED STATES

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

MEXICO

Agua Nueva Shale Oil AU 

Agua Nueva Shale Gas AU

TURONIAN

FINAL

AU MAP

102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

USA

MEXICO

Wilcox-Lobo Tight

 Gas AU 0 70 MILES

0 70 KILOMETERS

EXPLANATION

Burgos

Basin

Province

Wilcox-Lobo Tight Gas 

Assessment Unit 

Sabinas

Basin

Province

102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

USA

MEXICO

Rio Escondido Olmos

 Coalbed Gas AU 0 70 MILES

0 70 KILOMETERS

EXPLANATION

Burgos

Basin

Province

Rio Escondido 

Assessment Unit 

Sabinas

Basin

Province

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO

Tampico–Misantla

Basin Province

S I E R R A

M A D R E

O R I E N TA L

MEXICO

Burgos Basin

Province

Veracruz Basin

Province

Taumaulipas Arch Province

Magiscatzin Basin Province

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

Tithonian Organic Richness

1 to 2 weight-percent (2,985,373.05 acres)

> 2 weight-percent (793,400.95 acres)

EXPLANATION

Geologic province boundaries

Tithonian Total (6,098,147.59 Acres)

UNITED STATES

MEXICO

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

TITHONIAN

TOC

>1 WEIGHTPERCENT

102° 100° 98° 96° 94° 92°

32°

30°

28°

26°

24°

22°

20°

18°

16°

GULF 

OF 

MEXICO

PACIFIC OCEAN

UNITED STATES

MEXICO

Tampico-Misantla 

Basin Province

Veracruz Basin

Province

Burgos Basin

Province

Sabinas Basin

Province

Assessed provinces

Unassessed province

Eagleford Gas

Eagleford Oil EXPLANATION Smackover

Land

UNITED STATES

Area of

figure

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

MEXICO

0 50 100 150 200 MILES

0 50 100 150 200 KILOMETERS

Exposure of the Eagle Ford Formation 

(partly equivalent to the Agua Nueva 

Fm.) on the south bank of Lantry Creek in 

Pump Canyon, Val Verde County, Texas. 

Photograph taken by Michael Lewan, 

U.S. Geological Survey, August 19, 2010.

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO S I E R R A

M A D R E

O R I E N TA L

MEXICO

Burgos

Basin

Province

Veracruz

Basin

Province

Taumaulipas Arch

Magiscatzin Basin

Tampico–Misantla

Basin Province

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

Tithonian Thermal Maturity

Oil

Gas

EXPLANATION

Geologic province 

boundaries

TITHONIAN

THERMAL

MATURITY

UNITED STATES

MEXICO

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

USA

MEXICO

Agua Nueva Shale Gas AU 0 70 MILES

0 70 KILOMETERS

EXPLANATION

Burgos

Basin

Province

Sabinas

Basin

Province

TURONIAN

103° 102° 101° 100° 99° 98°

29°

28°

27°

26°

25°

24°

23°

La Casita Shale Gas AU

0 80 MILES

0 80 KILOMETERS

EXPLANATION

USA

MEXICO

Burgos

Basin

Province

Sabinas

Basin Province

TITHONIAN

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO S I E R R A

M A D R E

O R I E N TA L

MEXICO

Taumaulipas Arch

Magiscatzin Basin

Burgos

Basin

Province

Veracruz

Basin

Province

Tampico–Misantla

Basin Province

Turonian Thermal Maturity

Oil

Gas

EXPLANATION

Geologic province 

 boundaries

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

130°0'0"W 120°0'0"W 110°0'0"W 100°0'0"W 90°0'0"W 80°0'0"W 70°0'0"W 60°0'0"W

UNITED STATES

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

MEXICO

TURONIAN

THERMAL

MATURITY

Age

Tertiary Late Cretaceous Early Cretaceous Jurassic

Quaternary Pleistocene

Pliocene

Miocene

Oligocene

Eocene

Paleocene

Campanian

Santonian

Coniacian

Turonian

Cenomanian

Albian

Aptian

Barremian

Hauterivian

Valanginian

Berraisian

Tithonian

Kimmeridgian

Oxfordian

Maastrichtian

Gulfian Series Comanchean Coahuilan Neocomian Late

Burgos

Basin

South

Texas

TampicoMisantla

Basin

Sabinas Basin 

Continental beds in valleys

San

Felipe

Fm.

Austin

Fm. Indidura Fm.

Agua

Nueva Fm.

 Upper

Tamaulipas Fm.

Upper

Tamaulipas Fm.

Lower

Tamaulipas 

Fm.

Lower

Tamaulipas 

Fm.

Lower

Tamaulipas 

Fm.

Cuesta Del Cura Ls.

Mendez

Sh.

Mendez

Sh.

Escondido Fm.

Olmos Fm.

Upson Fm.

San Miguel Fm.

Eagle Ford

Fm.

Buda Ls.

Del Rio Sh.

Glen Rose Ls.

Sligo

San Felipe Fm.

La Pena Fm.

La Casita Fm. La Casita 

Fm.

Agua Nueva Fm.

Otates Fm.

La Pena Fm. Pearsall

Georgetown

 Fm.

Kiamichi Aurora Fm.

Ls.

Monclova Facies

Acatta

Evap.

Taraises

Fm.

San Marcos

Arkose

Olvido Fm.

Cupido

Ls.

Patula

La

Arkose Padilla

 Tongue

Barril Viejo

 Fm.

Menchaca Ls.

Hosston

Cotton

Valley

Haynesville

La Casista

Upper 

Tamaulipas

Tamabra

El Abra Pimienta

Bossier

La Gloria Zuloaga Ls. Smackover Ls. Smackover Smackover

Otates Fm.

Agua

Nueva

San

Felipe

Fm.

Mendez

Sh.

StuartCity Ls.

Mula

Sh.

La

Virgen

Evap.

?

Lissie Fm. Terraces Continental

Deposits Goliad

Fleming Tuxpan

Chapapote

Tantaoyuca

Guayabal

Aragon

Chicontepec

Escolin

Coatzintlas

Palma Real

Frio

Vicksburg

Jackson

Midway

Escondido Escondido

San Miguel

Anacacho Ls.

Olmos Olmos

Lobo Wilcox

Goliad Fm.

Lagarto Fm.

Anahuac Fm.

Frio Fm.

Vicksburg Fm.

Oakville Fm.

Fleming Gp.

Norma Cgl.

Jackson Fm.

Yegua Fm.

Cook Mtn. Fm.

Claiborne Gp.

Mt. Selman Fm.

Yegua Fm.

Cook Mtn. Fm.

Claiborne Gp.

Carrrizo

Wilcox Fm.

Midway Fm.

100° 99° 98° 97°

24°

23°

22°

21°

20°

19°

96°

GULF 

OF 

MEXICO

Tampico–Misantla

Basin Province

S I E R R A

M A D R E

O R I E N TA L

MEXICO

Burgos Basin

Province

Veracruz Basin

Province

Taumaulipas Arch Province

Magiscatzin Basin Province

Turonian Organic Richness

1-2 weight-percent (1,286,682.05 acres)

> 2 weight-percent (2,259,694.26 acres)

EXPLANATION

Province boundaries

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

UNITED STATES

Area of

study

PACIFIC

OCEAN

GULF OF

MEXICO

ATLANTIC

OCEAN

MEXICO

Turonian Total (4,217,581.22 Acres)

TURONIAN

TOC

> 1 WEIGHTPERCENT

Sabinas Basin

Tampico-Misantla Basin Burgos Basin

Introduction

The U.S. Geological Survey (USGS), in cooperation 

with the U.S. Department of State, quantitatively assessed 

the potential for unconventional oil and gas resources within the onshore portions of the Tampico-Misantla Basin, 

Burgos Basin, and Sabinas Basin provinces of northeastern 

Mexico (fig. 1). Unconventional resources of the Veracruz 

Basin were not quantitatively assessed because of a current 

lack of required geological information. Unconventional 

resources include shale gas, shale oil, tight gas, tight oil, 

and coalbed gas. Undiscovered conventional oil and gas resources were assessed in Mexico in 2012 (U.S. Geological 

Survey World Energy Assessment Team, 2012).

Methodology

The USGS approach to assessing continuous shale-oil 

and shale-gas resources in non-U.S. reservoirs is based 

upon developing a complete geologic framework description for each province from published literature and defining petroleum systems and unconventional assessment units 

(AUs) within these systems. We developed specific geologic criteria and a series of maps that define areas of resource 

potential within candidate reservoirs. To be considered for 

assessment, the potential shale-oil or shale-gas reservoir 

must possess the following criteria: (1) contain greater than 

2 weight-percent total organic carbon (TOC); (2) be within 

the proper thermal maturity window for oil or gas generation; (3) have greater than 15 meters (m) of organic-rich 

shale; (4) be greater than 1,000 m depth; (5) contain Type 

I or II organic matter, and (6) have evidence of moveable 

gas or oil in matrix storage (Charpentier and Cook, 2011). 

When applied to any given shale-oil or shale-gas reservoir, 

these specific criteria might reduce the potential area compared to maps made with greater than 1 weight-percent 

TOC, for example.

An important part of the geologic phase of this study 

was a formal USGS-PEMEX (Petroleos Mexicanos) 

Workshop on Unconventional Resources convened in 

Mexico City, Mexico, in June, 2012. The geology and current exploration results from within the various shale-oil 

and shale-gas assessment units (AU) of northeast Mexico 

were discussed in detail. PEMEX later supplied several 

maps with geologic data that were critical to the USGS assessment (PEMEX, 2012). The maps shown herein were 

combined to outline areas within the Sabinas, Burgos, and 

Tampico-Misantla Basins that were then considered for 

quantitative assessment using the six USGS criteria.

Northeastern Mexico 

Geologic Provinces Tithonian Pimienta / La Casita Formation

Agua Nueva Shale Oil AU La Casita Shale Gas AU

Wilcox-Lobo Tight Gas AU

Rio Escondido Olmos 

Coalbed Gas AU

Agua Nueva Shale Gas AU La Casita Shale Gas AU

Total Petroleum System

(TPS) 

and Assessment Unit (AU)

AU 

Probability

Field 

Type

Total Undiscovered Resources

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

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

BURGOS BASIN

Olmos Coalbed Gas TPS

Rio Escondido Coalbed 

Gas AU 53000281 1.0 Gas 125 479 1,544 612 0 0 0 0

Upper Jurassic La Casita TPS

La Casita Shale Gas AU 

53000361 1.0 Gas 1,148 3,253 6,730 3,516 69 195 407 211

Turonian Agua Nueva TPS

Agua Nueva Shale Oil AU 

53000461 1.0 Oil 52 129 251 138 96 252 533 275 2 5 11 6

Agua Nueva Shale Gas AU 

53000462 1.0 Gas 3,211 9,320 15,982 9,403 127 368 654 376

Paleogene TPS

Wilcox-Lobo Tight Gas AU 

53000561 1.0 Gas 535 1,675 3,431 1,785 5 16 36 18

SABINAS BASIN

Upper Jurassic La Casita TPS

La Casita Shale Gas AU 

53230161 1.0 Gas 577 1,899 4,687 2,172 17 56 144 65

Turonian Agua Nueva TPS

Agua Nueva Shale Gas AU 

53230261 1.0 Gas 941 3,189 7,922 3,650 37 127 321 146

TAMPICO-MISANTLA BASIN

Upper Jurassic Pimienta TPS

Pimienta Shale Oil AU 

53010261 1.0 Oil 69 194 412 212 82 232 498 254 2 7 15 8

Pimienta Shale Gas AU 

53010262 1.0 Gas 58 136 272 147 2 4 8 4

Turonian Agua Nueva TPS

Agua Nueva Shale Oil AU 

53010361 1.0 Oil 232 402 702 426 406 789 1,502 852 7 16 32 17

Agua Nueva Shale Gas AU 

53010362 1.0 Gas 252 754 1,529 808 10 30 62 32

VERACRUZ BASIN

Turonian Maltrata TPS

Maltrata Shale Oil AU 

53020261 Oil Not quantitatively assessed

Maltrata Shale Gas AU 

53020262 Gas Not quantitatively assessed

Total unconventional

 resources 353 725 1,365 776 7,431 21,978 44,630 23,474 278 824 1,690 883

Table 2. Northeast Mexico unconventional oil and gas resource assessment results.

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids; TPS, total petroleum system; AU, assessment unit. Results shown are fully risked estimates. For gas fields, all liquids are included under the 

NGL (natural gas liquids) category. F95 represents a 95 percent chance of at least the amount tabulated. Other fractiles are 

defined similarly. Shading indicates not applicable]

Assessment input data

Burgos Basin

Rio Escondido Olmos Coalbed Gas AU 53000281

Burgos Basin

La Casita Shale Gas AU 53000361

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 10,000 250,000 750,000 336,667 100,000 828,000 2,500,000 1,142,667

Average drainage area of wells (acres) 40 80 160 93 80 120 160 120

Percent of AU untested 100 100 100 100 100 100 100 100

Success ratios (%) 50 70 90 70 40 60 80 60

Average EUR (MMBO, oil; BCFG, gas) 0.03 0.2 1 0.24 0.3 0.6 0.9 0.61

Burgos Basin

Agua Nueva Shale Oil AU 53000461

Burgos Basin

Agua Nueva Shale Gas AU 53000462

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 100,000 704,000 1,100,000 634,667 100,000 2,259,000 3,530,000 1,963,000

Average drainage area of wells (acres) 160 280 400 280 80 120 160 120

Percent of AU untested 100 100 100 100 100 100 100 100

Success ratios (%) 50 70 90 70 50 70 90 70

Average EUR (MMBO, oil; BCFG, gas) 0.04 0.08 0.2 0.086 0.4 0.8 1.2 0.813

Burgos Basin

Wilcox-Lobo Tight Gas AU 53000561

Sabinas Basin

La Casita Shale Gas AU 53230161

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 10,000 550,000 700,000 420,000 94,000 565,000 1,882,000 847,000

Average drainage area of wells (acres) 40 110 180 110 80 120 160 120

Percent of AU untested 100 100 100 100 100 100 100 100

Success ratios (%) 50 70 90 70 10 50 90 50

Average EUR (MMBO, oil; BCFG, gas) 0.25 0.6 1.5 0.645 0.3 0.6 0.9 0.610

Sabinas Basin

Agua Nueva Shale Gas AU 53230261

Tampico-Misantla Basin

Pimienta Shale Oil AU 53010261

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 100,000 704,000 2,400,000 1,068,000 100,000 695,000 2,100,000 965,000

Average drainage area of wells (acres) 80 120 160 120 140 240 300 227

Percent of AU untested 100 100 100 100 100 100 100 100

Success ratios (%) 10 50 90 50 40 60 80 60

Average EUR (MMBO, oil; BCFG, gas) 0.4 0.8 1.2 0.813 0.03 0.08 0.14 0.082

Tampico-Misantla Basin

Pimienta Shale Gas AU 53010262

Tampico-Misantla Basin

Agua Nueva Shale Oil AU 53010361

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 10,000 33,000 100,000 47,667 1,052,000 2,104,000 2,735,000 1,963,667

Average drainage area of wells (acres) 80 120 160 120 160 280 400 280

Percent of AU untested 100 100 100 100 100 100 100 100

Success ratios (%) 40 60 80 60 50 70 90 70

Average EUR (MMBO, oil; BCFG, gas) 0.3 0.6 0.9 0.610 0.04 0.08 0.2 0.086

Tampico-Misantla Basin

Agua Nueva Shale Gas AU 53010362

Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 10,000 128,000 368,000 168,667

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

Percent of AU untested 100 100 100 100

Success ratios (%) 50 70 90 70

Average EUR (MMBO, oil; BCFG, gas) 0.4 0.8 1.2 0.813

Table 1. Key assessment input data for unconventional assessment units in northeast Mexico.

[EUR (estimated ultimate recovery per well), well drainage area, and success ratios are from U.S. shale-gas, shale-oil, tight-gas, and coalbed gas 

analogs. MMB, million barrels of oil; BCFG, billion cubic feet of gas; AU, assessment unit. The average EUR input is the minimum, median, maximum, 

and calculated mean]

Assessment Input Data Assessment Results

Discussion

The quantitative methodology used by the USGS for this assessment of unconventional oil and 

gas resources differs from that used in other unconventional assessments. The differences in methodology must be considered when attempting to compare assessment results. The potential area assessed 

by the USGS must have source rocks with greater than 2 weight-percent TOC, have greater than 15 

meter thickness of organic-rich shale, be within the proper thermal maturation windows for oil or gas 

generation. The maps supplied by PEMEX for the Agua Nueva and La Casita Formations in the Burgos Basin and Sabinas Basin were based on greater than 1 weight-percent TOC, so the areas used in 

the USGS assessments (>2 weight-percent TOC) are less than that shown on the PEMEX maps.

Assessment Input

Input to the assessment of unconventional oil and gas resources includes several key parameters that represent probability distributions that illustrate the uncertainty in these parameters 

(table 1). The distribution of potential area incorporates TOC, maturity, depth, and thickness data, 

and represents one of the key sources of geologic uncertainty. The distributions for estimated 

ultimate recovery (EUR), well drainage areas, and success ratio are from U.S. analog 

unconventional accumulations.

Assessment Results

Quantitative assessment results for 11 unconventional AUs of northeast Mexico are summarized in table 2. For unconventional oil resources, the mean total is 776 million barrels of oil 

(MMBO), with a range from 353 to 1,365 MMBO; for unconventional gas the mean total is 23,474 

billion cubic feet (BCFG), with a range from 7,431 to 44,630 BCFG; and a mean total of 883 million barrels of natural gas liquids (MMBNGL), with a range from 278 to 1,690 MMBNGL.

Of the mean unconventional oil total of 776 MMBO, about 82 percent is in the Tampico-Misantla 

Basin (55 percent; 426 MMBO) is estimated to be in the Agua Nueva Shale Oil AU; (27 percent; 

212 MMBO) is in the Pimienta Shale Oil AU. The Agua Nueva Shale Oil AU in the Burgos 

Basin contains the remaining (18 percent; 138 MMBO).

For the mean unconventional gas total of 23,474 BCFG, about 66 percent (15,591 BCFG)

is estimated to be in the Burgos Basin; 25 percent (5,822 BCFG) in the Sabinas Basin; and 

9 percent (2,061 BCFG) in the Tampico-Misantla Basin.

Assessment Team

Christopher J. Schenk, Ronald R. Charpentier, Timothy R. Klett, Marilyn E. Tennyson, 

Stephanie Gaswirth, Michael E. Brownfield, Mark J. Pawlewicz, and Jean N. Weaver.

References

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

petroleum resources: U.S. Geological Survey Open-File Report 2011–1167, 75 p.

PEMEX, 2012, Mexico’s shale oil/gas resources: PowerPoint presentation, July 10, 2012, 42 slides.

Peterson, J.A., 1985, Petroleum Geology and Resources of Northeastern Mexico: U.S. Geological Survey Circular 943, 30 p.

U.S. Geological Survey World Energy Assessment Team, 2012, Assessment of undiscovered 

conventional oil and gas resources of Mexico, Guatemala, and Belize, 2012: U.S. Geological 

Survey Fact Sheet 2012–3069, 4 p.

Warwick, P.D., 2007, Assessment of undiscovered oil and gas resources in Cretaceous-Tertiary 

coal beds of the Gulf Coast Region, 2007: U.S. Geological Survey Fact Sheet 2007–3039, 2 p.

Agua Nueva Shale Gas AU

Turonian Agua Nueva Formation

Geology and Assessment of Unconventional Oil and Gas Resources of Northeastern Mexico

By U.S. Geological Survey Mexico Assessment Team 

2015

Open-File Report 2015–1112

U.S. Department of the Interior

U.S. Geological Survey

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Suggested citation:

U.S. Geological Survey Mexico Assessment Team, 2014, Assessment of unconventional 

resources of northeastern Mexico: U.S. Geological Survey Open-File Report 2015–1112, 

1 sheet, http://dx.doi.org/10.3133/ofr20151112.

ISSN 2331-1258 (online)

http://dx.doi.org/10.3133/ofr20151112

The USGS approach to defining assessment units in the Tithonian Pimienta / La Casita Formation of the Tampico-Misantla Basin began with the map showing the distribution of total organic carbon (TOC) (fig. 4). The intersection of the map of TOC greater than 2 weight-percent (fig. 5) with the thermal maturity map (fig. 6) produced the 

AU map (fig. 7) for the modal shale-oil area (green) and shale-gas area (red) used in the assessment.

The USGS approach to defining AUs in the Turonian Agua Nueva Formation of the Tampico-Misantla Basin began with the map showing the distribution of TOC (fig. 8). 

The intersection of the map of TOC greater than 2 weight-percent (fig. 9) with the thermal maturity map (fig. 10) produced the AU map (fig. 11) for the modal shale-oil area 

(green) and shale-gas area (red) used in the assessment.

The USGS approach to defining AUs in the Turonian Agua Nueva Formation and in the Tithonian La Casita Formation of 

the Burgos Basin began with the map showing the distribution of TOC greater than one weight-percent (figs. 12–14). Using 

analog percentages for areas with greater than 2 weight-percent from the Tampico-Misantla Basin, the AUs were defined as 

areas with greater than 2 weight-percent TOC.

The USGS approach to defining AUs in the Turonian Agua Nueva Formation and 

in the Tithonian La Casita Formation of the Sabinas Basin began with the map showing 

the distribution of TOC greater than 1 weight-percent (figs. 17 and 18). Using analog 

percentages for areas with greater than 2 weight-percent from the Tampico-Misantla Basin, the AUs were defined as areas with greater than 2 weight-percent TOC, and with 

the additional condition that because of adverse effects of tectonism only about one 

third of the remaining area was estimated to have potential for shale oil or shale gas.