National and Global Petroleum Assessment

Assessment of Undiscovered Oil and Gas Resources 

in the Lower Indus Basin, Pakistan, 2017

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

technically recoverable resources of 164 million barrels of oil and 24.6 trillion cubic feet of gas in the Lower Indus 

Basin, Pakistan.

Introduction

The U.S. Geological Survey (USGS) 

completed an assessment of undiscovered, technically recoverable oil and gas 

resources within the Lower Indus Basin, 

Pakistan (fig. 1). The Lower Indus Basin 

is on the Indian-Pakistan plate, and as 

part of the supercontinent Gondwana 

during the Permian to Middle Jurassic, 

it underwent multiple phases of extension culminating in the separation of 

the Indian-Pakistan plate from Somalia 

in the Late Jurassic to Early Cretaceous 

(Robison and others, 1999; Zaigham and 

Mallick, 2000; Ahmad and others, 2012a). 

Subsequent separation of the Madagascar 

and Seychelles blocks from the IndianPakistan plate in the Late Cretaceous to 

Paleogene led to further extension and 

the initial formation of conventional 

structural traps that have been the focus 

of petroleum exploration (fig. 2) (Naeem 

and others, 2016). The western margin 

of the Indian-Pakistan plate was passive 

from the Early Cretaceous to Eocene, and 

petroleum source rocks of the Lower Goru 

and Sembar Formations were deposited 

along the west-facing passive margin during the Early Cretaceous.

Beginning in the Eocene, the IndianPakistan plate collided with Eurasia, 

which led to the formation of the Kirthar 

fold belt and the adjacent foreland basin. 

The Eocene collision also resulted in 

inversion, uplift, and erosion across the 

Indus Basin area, but deformation was 

focused within the fold belt.

Geologic Models for Assessment

In the Lower Indus Basin, the USGS defined the Lower Cretaceous 

Composite Total Petroleum System (TPS) with five assessment units 

(AUs) and the Jurassic TPS with one AU.

In the Lower Cretaceous Composite TPS, five AUs were geologically defined based on the presence and thermal maturation of marine 

and terrestrial organic matter in shales of the Lower Goru and Sembar 

Figure 1. Location of the Lower Indus Basin, Pakistan, and the six assessment units

(AUs) defined in this study.

60° 65° 70°

30°

25°

INDIA

PAKISTAN IRAN

AFGHANISTAN

ARABIAN SEA

INDUS

BASIN

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

0 100 200 MILES

0 200 KILOMETERS 100

ARABIAN

SEA

BAY

OF Map BENGAL

area

AFG KGZ

NPL

OMN

SAU

TJK TKM

ARE

UZB

CHN

IRN

PAK

IND Kirthar Foredeep Conventional Oil and Gas AU

Jacobabad-Mari Conventional Gas AU

Kirthar Fold Belt Conventional Gas AU

Jurassic Shale Gas AU

Lower Goru-Sembar Shale Oil AU

EXPLANATION

Lower Goru-Sembar Shale Gas AU

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2017–3034

September 2017
Formations (Quadri and Shuaib, 1986; Ahmad and 

others, 2012b; Siddiqui and others, 2014; Qayyum and 

others, 2016). Thickness of these source rocks is as 

much as 300 meters, total organic carbon is as much as 

9.5 weight percent, and shales contain Type II/III organic 

matter. The Kirthar Fold Belt Conventional Gas AU, the 

Kirthar Foredeep Conventional Oil and Gas AU, and 

the Jacobabad-Mari Conventional Gas AU were defined 

based on the regional tectonic setting and the presence 

of structural and stratigraphic traps (Ahmad and others, 

2012a). Conventional traps within these AUs may contain low-permeability reservoirs (Nizamuddin and others, 

2010; Majeed and Mahessar, 2016).

The geologic model for continuous accumulations 

in the Lower Goru-Sembar Shale Oil AU and Lower 

Goru-Sembar Shale Gas AU is for some portion of the 

oil and gas generated in these shales to have remained 

within the shales following migration, inversion, 

and uplift subsequent to the collision with Eurasia in 

the Eocene.

In the Jurassic TPS, the geologic model for the 

assessment of the Jurassic Shale Gas AU is for organicrich marine shales of the Jurassic (Type II organics, 

total organic carbon up to 2.8 weight percent, and 

thickness up to 50 meters) to have been buried deeply 

enough to reach thermal maturity for dry gas generation 

(Robison and others, 1999) with some portion of the gas 

retained within the shales to form a continuous shalegas accumulation.

Assessment input data for each AU are shown in 

table 1. For continuous AUs, well drainage areas, estimated ultimate recoveries, and success ratios are taken 

from U.S. shale-oil and shale-gas analogs.

Figure 2. West–east cross section in the southern part of the Lower Indus Basin, Pakistan (modified from Robison and others, 1999).

Undiscovered Resources Summary

The USGS quantitatively assessed undiscovered 

conventional and continuous oil and gas resources within 

the Lower Indus Basin (table 2). For total undiscovered 

oil and gas resources, the estimated means are 164 million 

barrels of oil (MMBO) with an F95–F5 range from 5 to 

436 MMBO; 24,625 billion cubic feet of gas (BCFG), or 

24.6 trillion cubic feet of gas, with an F95–F5 range from 

6,033 to 57,255 BCFG; and 601 million barrels of natural gas liquids (MMBNGL) with an F95–F5 range from 

118 to 1,482 MMBNGL. Values of zero at F95 reflect the 

chance that continuous gas might not be present in the AU, 

and the geologic AU probability was estimated to be less 

than one.

For undiscovered conventional oil and gas resources, 

the estimated means are 12 MMBO with an F95–F5 range 

from 5 to 21 MMBO, 7,139 BCFG with an F95–F5 range 

from 2,838 to 13,414 BCFG, and 139 MMBNGL with 

an F95–F5 range from 52 to 276 MMBNGL. Estimated 

mean resources in the Kirthar Fold Belt Conventional Gas 

AU are 4,005 BCFG with an F95–F5 range from 1,520 

to 7,662 BCFG and 79 MMBNGL with with an F95–F5 

range from 28 to 159 MMBNGL. The estimated means 

for oil resources in the Kirthar Foredeep Conventional 

Oil and Gas AU are 12 MMBO with an F95–F5 range 

from 5 to 21 MMBO, 32 BCFG (associated gas) with an 

F95–F5 range from 13 to 60 BCFG, and 1 MMBNGL with 

an F95–F5 range from 0 to 2 MMBNGL. The estimated 

means for nonassociated gas resources in the Kirthar 

Foredeep Conventional Oil and Gas AU are 1,312 BCFG 

with an F95–F5 range from 578 to 2,365 BCFG and 

51 MMBNGL with an F95–F5 range from 21 to 

98 MMBNGL. In the Jacobabad-Mari Conventional Gas 

AAXXXX_fig 01

0 25 MILES

0 25 KILOMETERS

WEST

KILOMETERS

EAST

0

1

2

3

4

Sea level

Tertiary

Upper Goru Lower Goru

Siwalik equivalent

Sembar

Jurassic

Triassic

Permian

Cretaceous

Sembar
Figure 3. Stratigraphic column for the Lower Indus

Basin, Pakistan (modified from Mahmoud, 2015).

Table 1. Key assessment input data for six assessment units in the Lower Indus 

Basin, Pakistan.

[AU, assessment unit; BCFG, billion cubic feet of gas; MMBO, million barrels of oil; %, percent; 

EUR, estimated ultimate recovery per well. EUR, well drainage area, and success ratios are partly 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]

Assessment input data

Kirthar Fold Belt Conventional Gas AU

Minimum Median Maximum Calculated 

mean

Number of gas fields 1 60 180 63.8

Sizes of gas fields (BCFG) 3 18 3,000 62.8

AU probability 1.0

Assessment input data

Kirthar Foredeep Conventional Oil and Gas AU

Minimum Median Maximum Calculated 

mean

Number of oil fields 1 10 30 10.6

Number of gas fields 1 50 150 53.2

Sizes of oil fields (MMBO) 0.5 0.8 12 10.6

Sizes of gas fields (BCFG) 3 12 600 24.7

AU probability 1.0

Assessment input data

Jacobabad-Mari Conventional Gas AU

Minimum Median Maximum Calculated 

mean

Number of gas fields 1 40 120 42.5

Sizes of gas fields (BCFG) 3 18 1,200 42.0

AU probability 1.0

Assessment input data

Lower Goru-Sembar Shale Oil AU

Minimum Mode Maximum Calculated 

mean

Potential production area of AU (acres) 1,200 1,807,000 3,614,000 1,807,400

Average drainage area of wells (acres) 80 160 240 160

Success ratios (%) 10 50 90 50

Average EUR (MMBO) 0.01 0.03 0.1 0.034

AU probability 0.8

Assessment input data

Lower Goru-Sembar Shale Gas AU

Minimum Mode Maximum Calculated 

mean

Potential production area of AU (acres) 1,200 8,158,000 16,316,000 8,158,400

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

Success ratios (%) 10 50 90 50

Average EUR (BCFG) 0.08 0.4 1 0.427

AU probability 1.0

Assessment input data

Jurassic Shale Gas AU

Minimum Mode Maximum Calculated 

mean

Potential production area of AU (acres) 1,200 3,263,000 16,316,000 6,526,733

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

Success ratios (%) 10 50 90 50

Average EUR (BCFG) 0.08 0.15 1 0.196

AU probability 0.5

AAXXXX_fig 01

Lithology

Chiltan

Limestone

Mazur Drik

Shales

System Series Formation

Holocene Alluvium

Kirthar

Laki

Ranikot

Khadro

Galinari

Eocene Paleocene Upper

Upper Goru Lower Goru Sembar

Lower

Middle Chiltan

Shinawari/

Datta

Lower

TERTIARY JURASSIC CRETACEOUS

EXPLANATION

Limestone

Sandstone

Shale

Volcanics

Coal

Unconformity

AU, the estimated means are 1,790 BCFG with an F95–F5 

range from 727 to 3,327 BCFG and 8 MMBNGL with an 

F95–F5 range from 3 to 17 MMBNGL.

For continuous shale-oil and shale-gas resources, the 

estimated total means are 152 MMBO with an F95–F5 

range from 0 to 415 MMBO, 17,486 BCFG with an F95–F5 

range from 3,195 to 43,841 BCFG, and 462 MMBNGL 

with an F95–F5 range from 66 to 1,206 MMBNGL. In the 

Lower Goru-Sembar Shale Oil AU, estimated means are 

152 MMBO with an F95–F5 range from 0 to 415 MMBO, 

390 BCFG (associated) with an F95–F5 range from 0 

to 1,108 BCFG, and 10 MMBNGL with an F95–F5 

range from 0 to 30 MMBNGL. Estimated means for the 

Lower Goru-Sembar Shale Gas AU are 14,455 BCFG 

(nonassociated) with an F95–F5 range from 3,195 to 

32,068 BCFG and 438 MMBNGL with an F95–F5 range 

from 66 to 1,116 MMBNGL. In the Jurassic Shale Gas AU, 

estimated means are 2,641 BCFG with an F95–F5 range 

from 0 to 10,665 BCFG and 14 MMBNGL with an F95–F5 

range from 0 to 60 MMBNGL
ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20173034

References Cited

Ahmad, Nadeem; Fink, Paul; Sturrock, Simon; Mahmood, Tariq; and Ibrahim, Muhammad, 2012a, Sequence stratigraphy as predictive tool in Lower Goru fairway, Lower 

and Middle Indus Platform, Pakistan: American Association of Petroleum Geologists, Search and Discovery Article No. 10404, April 23, 2012, 28 p., accessed April 27, 

2017, at http://www.searchanddiscovery.com/documents/2012/10404ahmad/ndx_ahmad.pdf?q=%2BauthorStrip%3Asturrock+-isMeetingAbstract%3Amtgabsyes.

Ahmad, Nazir; Mateen, Javed; Shehzad, Kashif; Mehmood, Nasar; and Arif, Fahad, 2012b, Shale gas potential of Lower Cretaceous Sembar Formation in Middle and Lower 

Indus sub-basins, Pakistan: American Association of Petroleum Geologists, Search and Discovery Article No. 10392, February 28, 2012, 25 p., accessed April 17, 2017, at 

http://www.searchanddiscovery.com/pdfz/documents/2012/10392ahmad/ndx_ahmad.pdf.html?q=%252BauthorStrip%253Ashehzad+-isMeetingAbstract%253Amtgabsyes.

Mahmoud, Salah, 2015, Integrated sequence stratigraphy of the Cretaceous Lower Goru deposits, Lower Indus Basin, Pakistan: American Association of Petroleum Geologists, Search and Discovery Article No. 10815, December 14, 2015, 37 p., accessed June 5, 2017, at http://www.searchanddiscovery.com/documents/2015/10815mahmoud/

ndx_mahmoud.pdf.

Majeed, Abdul; and Mahessar, A.A., 2016, Pakistan’s Kirthar fold belt tight-gas reservoirs show development potential: Oil and Gas Journal, December 5, 2016, p. 46–49, 

accessed April 17, 2017, at http://www.ogj.com/articles/print/volume-114/issue-12/exploration-development/pakistan-s-kirthar-fold-belt-tight-gas-reservoirs-showdevelopment-potential.html.

Naeem, Muhammad; Jafri, M.K.; Moustafa, S.S.R.; Al-Arifi, N.S.; Asim, Shazia; Khan, Farhan; and Ahmed, Nisar, 2016, Seismic and well log driven structural and 

petrophysical analysis of the Lower Goru Formation in the Lower Indus Basin, Pakistan: Geosciences Journal, v. 20, no. 1, p. 57–75.

Nizamuddin, M.A.; Aizad, Tanweer; Andress, G.R.; and Korosa, Marko, 2010, Hydraulic fracturing of tight gas reservoirs of Pab sandstones at POGC Rehman–1: 

Society of Petroleum Engineers Paper SPE–142849–MS, 16 p.

Qayyum, Faisal; Hanif, Muhammad; Mujtaba, Muhammad; Wahid, Sohail; and Ali, Fahad, 2016, Evaluation of source rocks using one dimensional maturity modeling 

in Lower Indus Basin, Pakistan: Arabian Journal of Geoscience, v. 9, no. 252, 22 p.

Quadri, V.N., and Shuaib, S.M., 1986, Hydrocarbon prospects of southern Indus Basin, Pakistan: American Association of Petroleum Geologists Bulletin, v. 70, no. 6, 

p. 730–747.

Robison, C.R., Smith, M.A., and Royle, R.A., 1999, Organic facies in Cretaceous and Jurassic hydrocarbon source rocks, southern Indus Basin, Pakistan: International 

Journal of Coal Geology, v. 39, nos. 1–3, p. 205–225.

Siddiqui, F.I.; Adhami, Asad; Asghar, Afnan; Hussain, Atif; and Khan, M.W.U., 2014, Shale gas potential of the Lower Goru Formation over the Lakhra High in Lower 

Indus Basin, Pakistan: American Association of Petroleum Geologists, Search and Discovery Article No. 80373, May 12, 2014, 28 p., accessed April 27, 2017, at 

http://www.searchanddiscovery.com/documents/2014/80373siddiqui/ndx_siddiqui.pdf?q=%2BauthorStrip%3Asiddiqui+-isMeetingAbstract%3Amtgabsyes.

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Petroleum Geologists Bulletin, v. 84, no. 11, p. 1833–1848.

For More Information

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

Lower Indus Basin Assessment Team

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

Gaswirth, Kristen R. Marra, Phuong A. Le, Sarah J. Hawkins, and Heidi M. Leathers-Miller

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

Lower Cretaceous Composite Total Petroleum System

Kirthar Fold Belt Conventional Gas AU 1.0 Gas 1,520 3,663 7,662 4,005 28 70 159 79

Kirthar Foredeep Conventional Oil and Gas AU 1.0 Oil 5 11 21 12 13 29 60 32 0 1 2 1

Gas 578 1,220 2,365 1,312 21 47 98 51

Jacobabad-Mari Conventional Gas AU 1.0 Gas 727 1,651 3,327 1,790 3 7 17 8

Total undiscovered conventional resources 5 11 21 12 2,838 6,563 13,414 7,139 52 125 276 139

Lower Cretaceous Composite Total Petroleum System

Lower Goru-Sembar Shale Oil AU 0.8 Oil 0 127 415 152 0 314 1,108 390 0 8 30 10

Lower Goru-Sembar Shale Gas AU 1.0 Gas 3,195 12,606 32,068 14,455 66 349 1,116 438

Jurassic Total Petroleum System

Jurassic Shale Gas AU 0.5 Gas 0 321 10,665 2,641 0 1 60 14

Total undiscovered continuous resources 0 127 415 152 3,195 13,241 43,841 17,486 66 358 1,206 462

Total undiscovered resources 5 138 436 164 6,033 19,804 57,255 24,625 118 483 1,482 601

Table 2. Assessment results for six assessment units in the Lower Indus Basin, Pakistan.

[MMBO, million barrels of oil; 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 in 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]