National and Global Petroleum Assessment

Assessment of Continuous Oil and Gas Resources of Solimões, 

Amazonas, and Parnaíba Basin Provinces, Brazil, 2016

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2017–3009

March 2017 Printed on recycled paper

Introduction

The U.S. Geological Survey (USGS) assessed undiscovered, 

technically recoverable continuous oil and gas resources within 

the Paleozoic Solimões, Amazonas, and Parnaíba Basin Provinces 

of Brazil (fig. 1). These Paleozoic basins share similar geologic characteristics that relate to oil and gas resource potential: 

(1) a progression from rifting, thermal sag, wrench faulting, and 

compression; (2) Devonian organic-rich shales deposited in the 

sag phase are the principal petroleum source rocks; (3) thermal 

maturation is a result of both burial and heating by widespread 

intrusives; and (4) geologic risk is based on the retention of oil 

and gas in the Devonian source rocks. The geologic definition of 

total petroleum systems (TPSs) and assessment units (AUs) reflect 

these common characteristics. For the Solimões Basin Province, 

the USGS defined a Devonian Jandiatuba TPS and the Solimões 

Jandiatuba Continuous Gas AU within this TPS. The Devonian 

Barreirinha TPS and the Amazonas Barreirinha Continuous Oil 

and the Amazonas Barreirinha Continuous Gas AUs were defined 

within the Amazonas Basin Province. The Devonian Pimenteiras 

TPS and the Parnaíba Pimenteiras Continuous Oil and the Parnaíba 

Pimenteiras Continuous Gas AUs were defined within the Parnaíba 

Basin Province. Published data on source-rock quality, thermal 

maturation, and thickness for the Solimões Basin (Mosmann 

and others, 1986; Mello and others, 1994), Amazonas Basin 

(Mosmann and others, 1986; Gonzaga and others, 2000), and the 

Parnaíba Basin (De Oliveira and Mohriak, 2003; Petersohn, 2011; 

De Miranda, 2014) were critical for TPS and AU definitions. These 

three TPSs share Devonian source rocks that are dominated by 

Type II marine kerogen; contain greater than 2 weight percent total 

organic carbon, as much as 8 weight percent; and have thicknesses 

of organic-rich shale greater than 15 meters.

Geologic Model for Assessment

With common geologic characteristics, the geologic model 

for the assessments summarized herein applies to each TPS. The 

geologic model is for oil and gas to have been generated by burial 

of source rocks beginning in the Permian and by the emplacement 

of dolerite dikes and sills in the Late Triassic to Early Cretaceous. 

In this model, oil and gas are partially retained within the matrix 

of organic-rich Devonian shales. Input for shale-oil assessment 

was modeled using vertical wells.

Assessment input data for the five assessment units are shown 

in table 1. Well drainage areas, estimated ultimate recoveries, and 

success ratios are taken from U.S. shale-oil and shale-gas analogs.

Undiscovered Resources Summary

The USGS quantitatively assessed undiscovered continuous oil 

and gas resources within the Solimões, Amazonas, and Parnaíba Basin 

Provinces of Brazil (table 2). For continuous oil resources, the estimated mean total is 5,019 million barrels of oil (MMBO), or 5 billion 

barrels of oil, with an F95–F5 range from 0 to 15,584 MMBO. For 

continuous gas resources, the estimated mean total is 47,201 billion cubic feet of gas (BCFG), or 47 trillion cubic feet of gas, with 

an F95–F5 range from 0 to 151,542 BCFG. For natural gas liquids, 

the estimated mean total is 897 million barrels of natural gas liquids 

(MMBNGL) with an F95–F5 range from 0 to 3,006 MMBNGL. For 

oil and gas accumulations, zeros at the F95 fractile reflect the interpretation of geologic risk (AU probability less than 1.0) on the potential 

occurrence of one well of minimum EUR in the AU.

Of the total resources, 68 percent (3,437 MMBO) of the continuous oil and 72 percent (33,816 BCFG) of the continuous gas is in 

the Amazonas Basin Province. The major source of geologic risk for 

continuous resources is the retention of oil or gas in the source rock following structural deformation and emplacement of intrusives.

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

mean continuous resources of 5 billion barrels of oil and 47 trillion cubic feet of gas in the Paleozoic Solimões, Amazonas, and 

Parnaíba Basin Provinces, Brazil.

Figure 1. Location of the Solimões, Amazonas, and Parnaíba Basin 

Provinces, Brazil, and the five assessment units (AUs) defined in this study.

70° 64° 58° 52° 46° 40°

6°

0°

6°

12°

18°

PARNAÍBA 

BASIN

SOLIMÕES 

BASIN

BRAZIL

BOLIVIA

PERU

COLOMBIA

VENEZUELA GUYANA

PERU

SURINAME

FRENCH 

GUIANA

ATLANTIC OCEAN

PACIFIC

OCEAN

AMAZONAS 

BASIN

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

Map

area

ATLANTIC

OCEAN

PACIFIC

OCEAN

BRAZIL

0 200 400 MILES

0 200 400 KILOMETERS

EXPLANATION

Solimões Jandiatuba Continuous Gas AU

Amazonas Barreirinha Continuous Oil AU

Amazonas Barreirinha Continuous Gas AU

Parnaíba Pimenteiras Continuous Oil AU

Parnaíba Pimenteiras Continuous Gas AU

Province boundary and identifier AMAZONAS

BASIN
ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20173009

References Cited

De Miranda, F.S., 2014, Pimenteiras Shale—Characterization of an atypical unconventional petroleum system, Parnaíba Basin, Brazil: American Association of Petroleum 

Geologists Search and Discovery Article No. 10639, accessed September 23, 2016, at http://www.searchanddiscovery.com/pdfz/documents/2014/10639demiranda/

ndx_demiranda.pdf.html?q=%252BtitleStrip%253Aparnaiba+-isMeetingAbstract%253Amtgabsyes.

De Oliveira, D.C., and Mohriak, W.U., 2003, Jaibaras trough—An important element in the early evolution of the Parnaíba interior sag basin, northern Brazil: Marine and 

Petroleum Geology, v. 20, p. 351–383.

Gonzaga, F.G., Gonçalves, F.T.T., and Coutinho, L.F.C., 2000, Petroleum geology of the Amazonas Basin, Brazil—Modeling of hydrocarbon generation and migration, in

Mello, M.R., and Katz, B.J., eds., Petroleum systems of South Atlantic margins: American Association of Petroleum Geologists Memoir No. 73, p. 159–178.

Mello, M.R., Koutsoukos, E.A.M., Mohriak, W.U., and Bacoccoli, Giuseppe, 1994, Selected petroleum systems in Brazil, in Magoon, L.B., and Dow, W.G., eds., The petroleum 

system—From source to trap: American Association of Petroleum Geologists Memoir No. 60, p. 499–512.

Mosmann, Raul, Falkenhein, F.U.H., Gonzalves, Alfredo, and Filho, F.N., 1986, Oil and gas potential of the Amazon Paleozoic basins, in Halbouty, M.T., ed., Future petroleum 

provinces of the world: American Association of Petroleum Geologists Memoir No. 40, p. 207–241.

Petersohn, Eliane, 2011, Brazil Round 9—Parnaíba Basin: Brazil National Agency of Petroleum, Natural Gas and Biofuels (ANP), 39 p., accessed December 28, 2016, at 

http://www.brasil-rounds.gov.br/round9/arquivos_r9/palestras/Parnaiba(ingles).pdf.

For More Information

Assessment results also are available at the USGS Energy Resources Program website at http://energy.usgs.gov.

Brazil Basin Provinces Assessment Team

Christopher J. Schenk, Marilyn E. Tennyson, Timothy R. Klett, Thomas M. Finn, Tracey J. Mercier, Sarah J. Hawkins, 

Stephanie B. Gaswirth, Kristen R. Marra, Michael E. Brownfield, Phuong A. Le, and Heidi M. Leathers-Miller

Assessment input data

Solimões Jandiatuba Continuous Gas AU Amazonas Barreirinha Continuous Gas AU

Minimum Mode Maximum Calculated

mean Minimum Mode Maximum Calculatedmean

Potential production area of AU (acres) 1,200 4,000,000 16,804,000 6,935,067 1,200 4,508,000 18,033,000 7,514,067

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

Percentage of area untested in AU 100 100 100 100 100 100 100 100

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

Average EUR (BCFG) 0.08 0.2 1.2 0.256 0.08 0.2 1.2 0.256

AU probability 0.6 0.8

Assessment input data

Amazonas Barreirinha Continuous Oil AU Parnaíba Pimenteiras Continuous Oil AU

Minimum Mode Maximum Calculated

mean Minimum Mode Maximum Calculatedmean

Potential production area of AU (acres) 800 12,159,000 48,637,000 20,256,600 800 7,530,000 30,121,000 12,550,600

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

Percentage of area untested in AU 100 100 100 100 100 100 100 100

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

Average EUR (MMBO) 0.01 0.03 0.1 0.034 0.01 0.03 0.1 0.034

AU probability 0.8 0.6

Assessment input data

Parnaíba Pimenteiras Continuous Gas AU

Minimum Mode Maximum Calculated

mean

Potential production area of AU (acres) 1,200 2,500,000 10,640,000 4,380,400

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

Percentage of area untested in AU 100 100 100 100

Success ratios (%) 10 50 90 50

Average EUR (BCFG) 0.08 0.2 1.2 0.256

AU probability 0.6

Table 1. Key assessment input data for five continuous assessment units in the Solimões, Amazonas, and Parnaíba Basin Provinces, Brazil.

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

barrels of natural gas liquids. Well drainage areas, EURs, and success ratios are taken from U.S. shale-oil and shale-gas analogs. The average EUR input is the 

minimum, median, maximum, and calculated mean. 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

Devonian Jandiatuba Total Petroleum System

Solimões Jandiatuba Continuous Gas AU 0.6 Gas 0 2,188 16,186 4,320 0 63 491 129

Devonian Barreirinha Total Petroleum System

Amazonas Barreirinha Continuous Oil AU 0.8 Oil 0 2,649 10,009 3,437 0 17,734 82,378 27,522 0 279 1,185 385

Amazonas Barreirinha Continuous Gas AU 0.8 Gas 0 4,329 20,040 6,294 0 126 609 189

Devonian Pimenteiras Total Petroleum System

Parnaíba Pimenteiras Continuous Oil AU 0.6 Oil 0 934 5,575 1,582 0 3,536 22,568 6,323 0 74 513 139

Parnaíba Pimenteiras Continuous Gas AU 0.6 Gas 0 1,404 10,370 2,742 0 27 208 55

Total undiscovered continuous resources 0 3,583 15,584 5,019 0 29,191 151,542 47,201 0 569 3,006 897

Table 2. Assessment results for five continuous assessment units in the Solimões, Amazonas, and Parnaíba Basin Provinces, Brazil.

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

gas accumulations, 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. Fractiles are additive under the assumption of perfect positive correlation. Shading indicates not applicable]