U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2016–3038

June 2016

National and Global Petroleum Assessment

Assessment of Shale-Gas Resources of the Karoo Province, 

South Africa and Lesotho, Africa, 2016

Introduction

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

assessment of continuous (unconventional) shale-gas resources 

within the Karoo Province (fig. 1), a geologically complex 

region of approximately 608,000 square kilometers in South 

Africa and Lesotho. As much as 8 kilometers of Carboniferous 

to Jurassic sedimentary rocks are present in the Karoo Province 

(Smith and others, 1993). Organic-rich petroleum source rocks 

are present in Lower Permian Prince Albert, Collingham, and 

Whitehill Formations, and these rocks are thermally mature 

with respect to gas generation. Eighty oil and gas exploration 

wells were drilled in the Karoo Province between 1965 and 

1977, with several reported gas shows but no conventional gas 

discoveries (IHS Energy, 2014).

Total Petroleum System and Assessment Units

For the Karoo Province, the USGS defined a Lower Permian 

Composite Total Petroleum System (TPS) and two shale gas 

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

resource of 44.5 trillion cubic feet of shale gas in the Karoo Province of South Africa and Lesotho, Africa.

Figure 1. Map of the Karoo Province and the two 

continuous assessment units defined in this study. AU, 

assessment unit.

assessment units (AUs) within this TPS. Gas shows from several 

wells in the province provide limited evidence that this petroleum 

system is viable.

The assessment of shale-gas resources by the USGS requires 

that the potential source-reservoir system must (1) have total 

organic carbon contents greater than 2 weight percent, (2) contain 

Type I or Type II organic matter, (3) be within the proper thermal 

maturity generation window, (4) have organic-rich shale greater 

than 15 meters in thickness, and (5) generally occur at depths 

greater than 1,500 meters (Charpentier and Cook, 2011). Using 

these parameters, the USGS defined the Whitehill-Collingham 

Shale Gas AU that includes Lower Permian lacustrine source 

rocks and the Prince Albert Shale Gas AU (fig. 1) that includes 

Lower Permian lacustrine source rocks (Faure and Cole, 1999). 

The major risk for the occurrence of recoverable shale gas in 

these AUs is considered to be retention of recoverable gas within 

the source rocks. The geologic model for this study is that an 

intrusion event began in the Early Jurassic and continued into the 

Late Jurassic (approximately 190 to 154 million years ago) and 

Source: National Park Service

ATLANTIC

OCEAN INDIAN

OCEAN

NAMIBIA

BOTSWANA

SWAZILAND

MOZAMBIQUE

LESOTHO

SOUTH AFRICA

Durban

MAPUTO

Port Elizabeth

Johannesburg

PRETORIA

(TSHWANE)

Cape Town

MASERU

Bloemfontein

35°

30°

25°

15° 20° 25° 30° 35°

Area of

study Karoo

Province

ATLANTIC

OCEAN

INDIAN

OCEAN

AFRICA

0 100 200 KILOMETERS

0 100 200 MILES

Karoo Province 

Whitehill-Collingham Shale Gas AU 

Prince Albert Shale Gas AU 

EXPLANATION
Table 2. Assessment results for the two continuous assessment units in the Karoo Province, South Africa.

[AU, assessment unit; BCFG, billion 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 under the NGL 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]

Total petroleum system and

assessment units (AU)

AU

probability

Accumulation

type

Total undiscovered resources

Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean

Lower Permian Composite Total Petroleum System

Whitehill-Collingham Shale Gas AU 0.6 Gas 0 8,977 62,132 16,993 0 86 632 170

Prince Albert Shale Gas AU 0.6 Gas 0 14,617 101,118 27,518 0 139 1,028 275

Total undiscovered

unconventional resources 0 23,594 163,250 44,511 0 225 1,660 445

Table 1. Key assessment input data for the two continuous assessment units in the Karoo Province, South Africa.

[AU, assessment unit; %, percent; EUR, estimated ultimate recovery per well; BCFG, billion cubic feet of gas. The EUR, well drainage area, and success ratios are 

taken from U.S. shale-gas analogs. The average EUR input is the minimum, median, and calculated mean. Shading indicates not applicable]

Assessment input data

Whitehill-Collingham Shale Gas AU Prince Albert Shale Gas AU

Minimum Mode Maximum Calculated

mean

Minimum Mode Maximum Calculated

mean

Potential production area of AU (acres) 10,000 5,808,000 42,000,000 15,939,333 10,000 9,610,770 68,249,000 25,956,590

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 0.4 1.0 0.427 0.08 0.4 1.0 0.427

AU probability 0.6 0.6

For More Information

Assessment results are available at the 

USGS Energy Resources Program Web site 

at http://energy.usgs.gov. 

ISSN 2327-6916 (print) ISSN 2327-6932 (online) http://dx.doi.org/10.3133/fs20163038

Karoo Province Assessment Team

Michael E. Brownfield, Christopher J. Schenk, Timothy R. Klett, Janet K. Pitman, 

Marilyn E. Tennyson, Stephanie B. Gaswirth, Phuong A. Le, Heidi M. Leathers-Miller, 

Tracey J. Mercier, and Thomas M. Finn

thermally altered Lower Permian source rocks in localized areas, resulting 

in the migration of gas from the source rocks. Breccia pipes in the Karoo 

Province are most likely vents for loss of gas following this intrusive event. 

Drilling and testing for recoverable gas in these source rocks will test the 

validity of this assessment model. 

Assessment input data for each assessment unit are shown in 

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

ratios are taken from U.S. shale-gas analogs.

Undiscovered Resource Summary

The USGS quantitatively assessed undiscovered gas resources within 

two shale gas assessment units in the Karoo Province (table 2). For shalegas resources, the estimated mean totals for the Whitehill-Collingham 

Shale Gas AU are 16,993 billion cubic feet of gas (BCFG), with an 

F95–F5 range from 0 to 62,132 BCFG; 170 million barrels of natural gas 

liquids (MMBNGL), with an F95–F5 range from 0 to 632 MMBNGL. 

Estimated mean totals for the Prince Albert Shale Gas AU are 27,518 

BCFG, with an F95–F5 range from 0 to 101,118 BCFG; 275 MMBNGL, 

with an F95–F5 range from 0 to 1,028 MMBNGL. The major source of 

geologic risk for shale-gas resources within the organic-rich shales of 

the Karoo Province is the retention of some portion of the generated gas 

within the source rock following any phases of gas migration.

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. [Also available at http://pubs.usgs.gov/

of/2011/1167/.]

Faure, Kevin, and Cole, Doug, 1999, Geochemical 

evidence from lacustrine microbial blooms in the vast 

Permian Main Karoo, Paraná, Falkland Islands and 

Huab basins of southwestern Gondwana: Palaeogeography, Palaeoclimatology, Paleoecology, v. 152, nos. 

3–4, p. 189–213.

IHS Energy, 2014, International petroleum exploration 

and production database [current through December 

2013]: IHS Energy, 15 Inverness Way East, Englewood, CO 80112.

Smith, R.M.H., Eriksson, P.G., and Botha, W.J., 1993, A 

review of the stratigraphy and sedimentary environments 

of the Karoo-aged basins of southern Africa: Journal of 

African Earth Sciences, v. 16, nos. 1–2, p. 143–169.