National and Global Petroleum Assessment

Assessment of Continuous Oil and Gas Resources in the 

Neuquén Basin Province, Argentina, 2016

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

mean continuous resources of 14.4 billion barrels of oil and 38 trillion cubic feet of gas in the Neuquén Basin Province, Argentina.

Introduction

The U.S. Geological Survey (USGS) assessed 

the potential for undiscovered, technically recoverable 

continuous (unconventional) oil and gas resources 

within the Neuquén Basin Province, Argentina 

(figs. 1–3). As defined by the USGS, the province

encompasses the basin (or “embayment”), the platform in the eastern part of the province, and the fold 

belt in the western part of the province. This study 

estimated potential volumes of undiscovered continuous oil and gas in three petroleum source rocks that 

occur in the basin and in the fold belt: the Jurassic 

Los Molles Formation, the Jurassic–Early Cretaceous

Vaca Muerta Formation, and the Early Cretaceous

Agrio Formation. The USGS defined a Los Molles

Total Petroleum System (TPS), a Vaca Muerta TPS, 

and an Agrio TPS, following similar published 

definitions of these systems (Urien and Zambrano,

1994; Legarreta and Villar, 2015). Twelve continuous 

resource assessment units (AUs) were defined within

these three TPSs (table 1).

Geologic Model for Assessment

Three main assumptions underlie the geologic 

model that forms the foundation of this assessment. 

First, some portion of the oil and gas generated in each 

of the three source rocks was retained within each 

source rock interval and constitutes potentially recoverable oil or gas. Second, multiple phases of structural 

deformation in the fold belt negatively affected the 

volumes of oil or gas retained in source rocks compared to those retained in the basin or embayment 

area. Third, the assessment was based mainly (but not 

entirely) on vertical wells, which affects the input data 

for the USGS assessment methodology (for example, 

well drainage areas, estimated ultimate recoveries, and 

success ratios). Given the geologic model, the definition of AUs was based on (1) whether the source rock 

resides within the fold belt or embayment, (2) the level 

of thermal maturation, (3) the percent of total organic 

(

(

( ( (

–72° –71° –70° –69° –68° –67° –66°

–35°

–36°

–37°

–38°

–39°

–40°

Neuquén

Talca

San Fernando

Temuco

CEROOS

COLORADOS

RESERVOIR

EZEQUIEL

RAMOS MEXIA

RESERVOIR

ARGENTINA

CHILE

(

Neuquén Basin Province boundary

Los Molles Embayment Continuous Gas AU

Los Molles Fold Belt Continuous Gas AU

Los Molles Embayment Continuous Oil AU

Los Molles Embayment Tight Sandstone Gas AU

Los Molles Fold Belt Continuous Oil AU

Fold belt

EXPLANATION

0 75 MILES

0 75 KILOMETERS

Source: U.S. Department of the Interior National Park Service

BRA

BOL

URY

PRY

PER

CHL

ARG

COL

VEN GUYSUR

GUF

ECU

SOUTH

ATLANTIC

OCEAN

SOUTH

PACIFIC

OCEAN

Map

area

Figure 1. Location of the five assessment units (AUs) in the Los Molles Total 

Petroleum System of the Neuquén Basin Province, Argentina.

carbon, and (4) the thickness of viable source rock. Source rock data for 

the Los Molles TPS, Vaca Muerta TPS, and Agrio TPS from published 

sources are summarized in table 2 (Legarreta and others, 2005; Tyson 

and others, 2005; Martinez and others, 2008; Schmidt and others, 2013; 

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2017–3025

May 2017
Barredo and Stinco, 2014; Legarreta and Villar, 2015; Licitra 

and others, 2015; Rimedio and others, 2015). The lower limits 

of thickness of effective source rock (15 meters), total organic 

carbon (2 weight percent), and hydrogen index (200 milligrams 

hydrocarbon per gram of total organic carbon) are the thresholds used by the USGS to define a viable continuous accumulation (table 2).

Key assessment input data for 12 AUs are summarized 

in table 1. Data for estimated ultimate recovery, well drainage area, and success ratios were based on U.S. analogs for 

continuous oil and gas reservoirs.

Undiscovered Resources Summary

The USGS assessed potential undiscovered, technically recoverable continuous resources in the Neuquén Basin 

Province, Argentina (table 3). The USGS estimated mean 

totals of 14,370 million barrels of continuous oil (MMBO), 

or 14.4 billion barrels of oil, with an F95–F5 range from

4,139 to 27,913 MMBO; 37,966 billion cubic feet of continuous gas (BCFG), or 38 trillion cubic feet of continuous

gas, with an F95–F5 range from 10,382 to 76,102 BCFG;

and 482 million barrels of natural gas liquids (MMBNGL) 

with an F95–F5 range from 113 to 1,055 MMBNGL

(table 3).

In the Los Molles TPS, the estimated mean totals for continuous oil and gas resources are 847 MMBO with an F95–F5

range from 220 to 1,775 MMBO, 18,137 BCFG with an F95–F5

range from 4,993 to 36,000 BCFG, and 184 MMBNGL with

an F95–F5 range from 44 to 400 MMBNGL. The Vaca Muerta

TPS has estimated mean totals for continuous oil and gas 

resources of 12,848 MMBO with an F95–F5 range from 3,750

to 24,696 MMBO, 19,155 BCFG with an F95–F5 range from

5,232 to 38,597 BCFG, and 287 MMBNGL with an F95–F5

range from 67 to 630 MMBNGL. In the Agrio TPS, the estimated mean totals for continuous oil and gas resources are 

675 MMBO with an F95–F5 range from 169 to 1,442 MMBO,

674 BCFG with an F95–F5 range from 157 to 1,505 BCFG, and

11 MMBNGL with an F95–F5 range from 2 to 25 MMBNGL.

Most of the continuous oil resources (12,848 MMBO 

or 89 percent) are estimated to be in three assessment 

units of the Vaca Muerta TPS. Half of the mean continuous gas resources (19,155 BCFG or 50 percent) is in the

Vaca Muerta TPS, and 48 percent (18,137 BCFG) is in the

Los Molles TPS.

(

(

( ( (

–72° –71° –70° –69° –68° –67° –66°

–35°

–36°

–37°

–38°

–39°

–40°

Neuquén

Talca

San Fernando

Temuco

CEROOS COLORADOS

RESERVOIR

CEROOS COLORADOS

RESERVOIR

EZEQUIEL

RAMOS MEXIA

RESERVOIR

ARGENTINA

CHILE

(

Vaca Muerta Embayment Continuous Oil AU

Vaca Muerta Fold Belt Continuous Oil AU

Vaca Muerta Embayment Continuous Gas AU

Neuquén Basin Province boundary

Vaca Muerta Fold Belt Continuous Gas AU

Vaca Muerta Picún Leufú Basin Continuous Oil AU

Fold belt

EXPLANATION

0 75 MILES

0 75 KILOMETERS

Source: U.S. Department of the Interior National Park Service

BRA

BOL

URY

PRY

PER

CHL

ARG

COL

VEN GUYSUR

GUF

ECU

SOUTH

ATLANTIC

OCEAN

SOUTH

PACIFIC

OCEAN

Map

area

Figure 2. Location of the five assessment units (AUs) in the Vaca 

Muerta Total Petroleum System of the Neuquén Basin Province, 

Argentina.

(

(

( ( (

–72° –71° –70° –69° –68° –67° –66°

–35°

–36°

–37°

–38°

–39°

–40°

Neuquén

Talca

San Fernando

Temuco

CEROOS

COLORADOS

RESERVOIR

EZEQUIEL

RAMOS MEXIA

RESERVOIR

ARGENTINA

CHILE

(

Neuquén Basin Province boundary

Agrio Embayment Continuous Oil AU

Agrio Fold Belt Continuous Oil AU

Fold belt

EXPLANATION

0 75 MILES

0 75 KILOMETERS

BRA

BOL

URY

PRY

PER

CHL

ARG

COL

VEN GUYSUR

GUF

ECU

SOUTH

ATLANTIC

OCEAN

SOUTH

PACIFIC

OCEAN

Map

area

Source: U.S. Department of the Interior National Park Service

Figure 3. Location of the two assessment units (AUs) in the Agrio 

Total Petroleum System of the Neuquén Basin Province, Argentina.
References Cited

Barredo, S.P., and Stinco, L.P., 2014, Unconventional reservoir geology of the Neuquén Basin, Argentina, in Society of Petroleum Engineers, SPE Annual Conference and

Exhibition, Amsterdam, Netherlands, October 27–29, 2014, Proceedings: Society of Petroleum Engineers, Paper SPE–170905–MS, 11 p., accessed September 30, 2016, at

https://www.onepetro.org/conference-paper/SPE-170905-MS.

Legarreta, Leonardo, Cruz, C.E., Vergani, Gustavo, Laffitte, G.A., and Villar, H.J., 2005, Petroleum mass-balance of the Neuquén Basin,Argentina—Acomparative assessment of

the productive districts and non-productive trends: American Association of Petroleum Geologists, Search and Discovery Article No. 10080, 7 p., accessed September 30, 2016, 

at http://www.searchanddiscovery.com/pdfz/documents/2005/legarreta/images/legarreta.pdf.html.

Legarreta, Leonardo, and Villar, J.J., 2015, The Vaca Muerta Formation (Late Jurassic–Early Cretaceous), Neuquén Basin, Argentina—Sequences, facies, and source rock characteristics, in Unconventional Resources Technology Conference, San Antonio, Texas, July 20–22, 2015, Proceedings: Unconventional Resources Technology Conference,

Paper URTeC:2170906, 15 p., accessed September 30, 2016, at http://www.geolabsur.com/Biblioteca/Legarreta_Villar_2015_VM_Urtec.pdf.

Licitra, Diego; Lovrincevich, Eliana; Vittore, Franco; Quiroga,Juan; Oviedo, Pablo; Montoya, Veronica; Shannon, Coleen; and Monti, Luciano, 2015, Sweetspotsin Vaca Muerta—

Integration ofsubsurface and production data in Loma Campana shale development,Argentina, in Unconventional Resources Technology Conference, SanAntonio, Texas,

July 20–22, 2015, Proceedings: Unconventional Resources Technology Conference, Paper URTeC:2153944, 18 p., accessed September 30, 2016, at https://www.onepetro.org/

conference-paper/SPE-178563-MS.

Martínez, M.A., Prámparo, M.B., Quattrocchio, M.E., and Zavala, C.A., 2008, Depositional environments and hydrocarbon potential of the Middle Jurassic Los Molles Formation, Neuquén Basin, Argentina—Palynofacies and organic geochemical data: Andean Geology (formerly known as Revista Geológica de Chile), v. 35, no. 2, p. 235–247.

Rimedio, Milena; Shannon, Coleen; Monti, Luciano; Lerza, Alejandro; Roberts, Matthew; and Quiroga, Juan, 2015, Interference behavior analysis in Vaca Muerta shale oil

development, Loma Campana Field, Argentina, in Unconventional Resources Technology Conference, San Antonio, Texas, July 20–22, 2015, Proceedings: Unconventional Resources Technology Conference, MS/URTeC:2154859, 14 p., accessed September 30, 2016, at https://www.onepetro.org/conference-paper/SPE-178620-MS.

Schmidt, N.G., Alonso, J.C., and Giusiano, Adolfo, 2013, Assessment of Vaca Muerta Formation shale oil—Production decline–curve analysis, in Workshop on Unconventional Reservoirs, Ministry of Energy, Neuquén Province, Argentina, April 17, 2013: Workshop on Unconventional Reservoirs, 31 p., accessed September 30, 2016, at

http://www.energianeuquen.gov.ar/cms/files/contenido/70/4Evaluacion%20Shale%20IAPG%20abril2013.pdf.

Tyson, R.V., Esherwood, Philip, and Pattison, K.A., 2005, Organic facies in the Valanginian–mid-Hauterivian interval of theAgrio Formation (Chos Malal area, Neuquén,

Argentina)—Local significance and global context, in Veiga, G.D., Spalletti, L.A., Howell, J.A., and Schwarz, E., eds., The Neuquén Basin,Argentina—Acase study in

sequence stratigraphy and basin dynamics: Geological Society of London, Special Publication No. 252, p. 251–266.

Urien, C.M., and Zambrano, J.J., 1994, Petroleum systems in the Neuquén Basin,Argentina, in Magoon, L.B., and Dow, W.G., eds., The petroleum system—From source to trap:

AmericanAssociation of Petroleum Geologists Memoir No. 60, p. 513–534.

Table 1. Key assessment input data for 12 continuous assessment units in the Neuquén Basin Province, Argentina.

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

area, and well success ratios are from U.S. shale-gas, tight-gas, and shale-oil analogs. The EUR input includes the minimum, median, maximum, and calculated

mean. Shading indicates not applicable]

Assessment input data Los Molles Embayment Continuous Oil AU Los Molles Embayment Continuous Gas AU

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 2,400 480,000 960,000 480,800 4,800 1,556,000 3,112,000 1,557,600

Average drainage area of wells (acres) 20 60 120 67 80 120 160 120

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

Average EUR (MMBO, oil; BCFG, gas) 0.08 0.1 0.3 0.111 0.2 0.4 1.0 0.431

AU probability 1.0 1.0

Assessment input data Los Molles Fold Belt Continuous Oil AU Los Molles Fold Belt Continuous Gas AU

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 600 717,000 2,391,000 1,036,200 3,000 2,407,000 8,670,000 3,693,333

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

Success ratios (%) 10 30 50 30 10 30 50 30

Average EUR (MMBO, oil; BCFG, gas) 0.03 0.06 0.1 0.062 0.2 0.35 0.8 0.373

AU probability 1.0 1.0

Assessment input data Los Molles Embayment Tight Sandstone Gas AU Vaca Muerta Embayment Continuous Oil AU

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 9,600 1,800,000 3,112,000 1,640,533 3,000 2,407,000 3,438,000 1,949,333

Average drainage area of wells (acres) 40 80 120 80 20 60 120 67

Success ratios (%) 65 75 85 75 75 85 95 85

Average EUR (BCFG, gas; MMBO, oil) 0.2 0.6 1.4 0.637 0.2 0.4 0.7 0.412

AU probability 1.0 1.0

Assessment input data Vaca Muerta Embayment Continuous Gas AU Vaca Muerta Fold Belt Continuous Oil AU

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 6,000 928,000 1,325,000 753,000 600 1,005,000 3,350,000 1,451,867

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

Success ratios (%) 75 85 95 85 10 30 50 30

Average EUR (BCFG, gas; MMBO, oil) 0.2 0.8 2.0 0.856 0.03 0.06 0.10 0.062

AU probability 1.0 1.0

Assessment input data Vaca Muerta Fold Belt Continuous Gas AU Vaca Muerta Picún Leufú Basin Continuous Oil AU

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 1,200 1,332,000 4,439,000 1,934,067 3,000 690,000 986,000 559,667

Average drainage area of wells (acres) 80 120 160 120 20 60 120 67

Success ratios (%) 10 30 50 30 70 80 90 80

Average EUR (BCFG, gas; MMBO, oil) 0.2 0.35 0.8 0.373 0.1 0.2 0.35 0.206

AU probability 1.0 1.0

Assessment input data Agrio Embayment Continuous Oil AU Agrio Fold Belt Continuous Oil AU

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 2,400 268,000 535,000 268,467 600 1,085,000 3,615,000 1,566,867

Average drainage area of wells (acres) 20 60 120 67 40 80 120 80

Success ratios (%) 50 70 90 70 10 30 50 30

Average EUR (MMBO) 0.06 0.09 0.3 0.102 0.03 0.06 0.1 0.062

AU probability 1.0 1.0
Table 2. Summary of source rock data for three total petroleum systems in the 

Neuquén Basin Province, Argentina.

[TPS, total petroleum system; m, meters; wt %, weight percent; % Ro, percent vitrinite reflectance; 

mg HC/g TOC, milligrams of hydrocarbon per gram of total organic carbon]

Los Molles

TPS

Vaca Muerta

TPS

Agrio

TPS

Maximum formation thickness (m) 2,100 1,200 1,500

Thickness of effective source rock (m) 15–800 15–450 15–400

Total organic carbon (wt %) 2–5 2–12 2–7

Maximum thermal maturation (% Ro) 3 2 3.6

Hydrogen index (mg HC/g TOC) 200–500 200–800 200–550

Kerogen type III/II I/II/IIS II/III

Table 3. Assessment results for 12 assessment units in the Neuquén Basin Province, Argentina.

[MMBO, million barrels of oil; BCFG, billions of cubic feet of gas; NGL, natural gas liquids; MMBNGL, million barrels of natural gas liquids. Results shown

are fully risked estimates. For gas accumulations, all liquids are included as natural gas liquids. F95 represents a 95-percent chance of at least the tabulated amount 

being present; other fractiles are defined similarly. Fractiles are additive under the assumption of perfect positive correlation. Shading indicates not applicable]

Total petroleum systems

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

Los Molles Total Petroleum System

Los Molles Embayment

Continuous Oil AU 1.0 Oil 163 544 1,236 601 151 528 1,298 601 2 8 21 9

Los Molles Embayment

Continuous Gas AU 1.0 Gas 1,116 3,644 7,631 3,913 15 52 126 59

Los Molles Fold Belt

Continuous Oil AU 1.0 Oil 57 215 539 246 54 210 562 246 1 3 9 4

Los Molles Fold Belt

Continuous Gas AU 1.0 Gas 779 2,982 7,665 3,450 10 43 124 52

Los Molles Embayment

Tight Sandstone Gas AU 1.0 Gas 2,893 9,374 18,844 9,927 16 55 120 60

Total resources 220 759 1,775 847 4,993 16,738 36,000 18,137 44 161 400 184

Vaca Muerta Total Petroleum System

Vaca Muerta Embayment

Continuous Oil AU 1.0 Oil 3,228 10,365 21,092 11,008 3,004 10,057 22,253 11,007 39 144 363 165

Vaca Muerta Embayment

Continuous Gas AU 1.0 Gas 1,329 4,261 8,587 4,512 17 61 141 68

Vaca Muerta Fold Belt

Continuous Oil AU 1.0 Oil 79 303 753 345 74 294 785 344 1 4 13 5

Vaca Muerta Fold Belt

Continuous Gas AU 1.0 Gas 412 1,562 3,972 1,798 5 23 64 27

Vaca Muerta Picún Leufú 

Basin Continuous Oil AU 1.0 Oil 443 1,415 2,851 1,495 413 1,370 3,000 1,494 5 20 49 22

Total resources 3,750 12,083 24,696 12,848 5,232 17,544 38,597 19,155 67 252 630 287

Agrio Total Petroleum System

Agrio Embayment

Continuous Oil AU 1.0 Oil 82 272 629 303 76 264 661 303 1 4 11 5

Agrio Fold Belt

Continuous Oil AU 1.0 Oil 87 325 813 372 81 317 844 371 1 5 14 6

Total resources 169 597 1,442 675 157 581 1,505 674 2 9 25 11

Total undiscovered

continuous resources 4,139 13,439 27,913 14,370 10,382 34,863 76,102 37,966 113 422 1,055 482

Neuquén Basin Province Assessment Team

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

Tracey J. Mercier, Janet K. Pitman, Stephanie B. Gaswirth, Thomas M. 

Finn, Michael E. Brownfield, Phuong A. Le, Heidi M. Leathers-Miller,

and Kristen R. Marra

For More Information

Assessment results are available at the USGS Energy Resources

Program website at https://energy.usgs.gov.

ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20173025