U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3070

August 2009

Assessment of Undiscovered Petroleum Resources

of Southern and Western Afghanistan, 2009

Printed on recycled paper

Introduction

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

Afghanistan Ministry of Mines, assessed the undiscovered petroleum resource potential of western and southern Afghanistan. The 

assessment is part of U.S. and Afghan Government efforts to assist 

in the rebuilding of the Afghan economy and infrastructure through 

identification and development of natural resources.

The Tirpul Basin is a transpressional basin located in western Afghanistan, extending from near Herat in the east, to the 

Iranian border in the west (fig. 1). The basin is generally bounded 

on the north by the Safed-Koh Anticline and on the south by the 

Herat/Hari Rud Fault Zone. The areal extent of the Tirpul Basin 

is approximately 8,700 km2. Significant exploration efforts during 

the 1970s and 1980s included gravity and magnetic surveys and 

the drilling of several exploratory wells. A more recent gravity 

and magnetic survey was completed in 2006. There is no oil or 

gas production in the Tirpul Basin.

The Helmund Basin is situated in southwestern Afghanistan 

(fig. 1), southwest of Kandahar and north of the Chaga Hills. For 

resource assessment purposes, the basin corresponds to an area 

in which gravity and magnetic data are interpreted to indicate 

a sedimentary rock thickness greater than 1,500 m (Drenth and 

Finn, 2008). Gravity and magnetic surveys are the only exploration efforts conducted to date. No rocks with petroleum potential 

are exposed in the basin.

The Katawaz Basin in southern Afghanistan (fig. 1) consists of accreted terrane in the collision zone of the Helmund 

and Indian tectonic plates. The areal extent of the entire basin is 

approximately 45,000 km2; it is bounded on the northwest by the 

Chaman Fault Zone and on the south and east by the Muslimabad 

Ophiolite Zone. Petroleum geology studies as well as gravity and 

magnetic surveys have been conducted in the basin. No exploratory wells have been drilled and no seismic surveys have been 

conducted in the Afghan part of the basin.

Geologic Definition of Assessment Units

Both the Tirpul Basin Upper Mesozoic–Paleogene Total 

Petroleum System (TPS) (802301) and Tirpul Assessment Unit 

(AU) (80230101) boundaries are coincident with the Tirpul 

Using a geology-based assessment methodology, 

the U.S. Geological Survey–Afghanistan Ministry of 

Mines Joint Oil and Gas Resource Assessment Team 

estimated mean undiscovered resource volumes of 

21.55 million barrels of oil, 44.76 billion cubic feet of 

non-associated natural gas, and 0.91 million barrels of 

natural gas liquids in the western Afghanistan Tirpul 

Assessment Unit (AU) (80230101).

Basin boundary (fig. 1). The areal extent of the TPS and AU is 

approximately 8,700 km2. Recurrent movements of multiple 

fault blocks within the basin caused variations in deposition 

and erosion of the rock strata, resulting in uncertainty as to the 

existence and quality of source and reservoir rocks in individual 

fault blocks. Several rock units in the Jurassic to Eocene strata 

may be potential source rocks. However, none of the rocks 

sampled thus far (fig. 1) demonstrates sufficient organic richness or thermal maturity to generate hydrocarbons. Oil seeping from one abandoned well indicates that oil generation has 

occurred within the basin. Analysis of the oil indicates that it 

was generated from a Tertiary age source rock deposited in a 

saline lacustrine environment.

The Helmund Basin Paleocene-Miocene TPS (802201) 

and Paleocene-Miocene AU (80220101) are hypothetical. The 

Paleocene-Miocene TPS and Paleocene-Miocene AU boundaries 

are coincident. The area included in the TPS and AU is the area 

in which magnetic gravity surveys indicate a sedimentary rock 

thickness greater than 1,500 m. The extent of the AU and TPS is 

approximately 41,000 km2. Bounding and within the AU are intrusive and extrusive igneous rocks of significant areal extent.

The Katawaz Basin Eocene-Miocene TPS (802401) and 

Eocene-Miocene Deltaic AU (80240101) are hypothetical. The 

Eocene-Miocene TPS and Eocene-Miocene Deltaic AU boundaries are coincident. The area included in the TPS and AU is the 

Figure 1. Satellite image of southern and western Afghanistan 

showing prospective assessment units of the Tirpul Basin (AU 80230101), 

Helmund Basin (AU 80220101), and Katawaz Basin (AU 80240101); 

well and sample locations; and relevant faults. Image from National 

Geospatial Intelligence Agency, 12 July 2004, unclassified.

0 50 100 KILOMETERS

30°

35°

65° 70°

Herat

Kandahar

Ghazni

Khost

Kabul

IRAN

PAKISTAN

AU 80230101

AU 80220101

AU 80240101 CHAMAN FAULT ZONE

Quetta

AFGHANISTAN

Chaga Hills

Helmund

Basin

Katawaz Basin

Tirpul Basin

Muslimabad Ophiolite Zone

HERAT/HARI RUD FAULT ZONE

Safed Kohl Anticline

AFGHANISTAN

60°

Fault

Well

Sampling location

Assessment unit
area where magnetic and gravity surveys indicate sedimentary 

rock thickness greater than 1,500 m. The extent of the AU and 

TPS is approximately 27,000 km2. Potential source rocks are 

Eocene and Oligocene marine and deltaic shales and mudstones. 

High thermal maturity values for surface samples indicate that 

the AU will be gas-prone. Continued extensive deformation 

and destruction of the basin’s potential reservoir rocks and traps 

greatly reduce the chances for the entrapment and preservation 

of significant quantities of oil or gas.

Summary

Investigation of the petroleum resource potential of southern and western Afghanistan has been very limited, although 

considerable exploration has previously occurred in both the 

Amu Darya and Afghan-Tajik Basins of northern Afghanistan. 

There has been no exploratory drilling in the Helmund Basin 

or Afghan part of the Katawaz Basin, and no more than five 

exploratory wells have been drilled in the Tirpul Basin. Continued tectonic activity has compromised both reservoir quality 

and trap integrity in all three basins.

The Assessment of Undiscovered Petroleum Resources 

of Southern and Western Afghanistan is based on the geologic 

elements of a total petroleum system, which include (1) sourcerock presence, richness, type, maturation, generation, and migration; (2) presence and quality of reservoir rocks; and (3) time of 

trap formation with respect to petroleum migration, trap size, and 

type. Where available, data from studies of geophysics, geochemistry, petroleum geology, tectonics, and analog basins were 

used to aid in estimating the number and sizes of undiscovered 

petroleum accumulations. The minimum field mean field size 

quantitatively assessed was 5 million barrels of oil (MMBO) 

and 30 billion cubic feet of gas (BCFG).

Resource Summary

The U.S. Geological Survey–Afghanistan Ministry of 

Mines Joint Oil and Gas Resource Assessment Team assessed 

undiscovered conventional, technically recoverable petroleum 

(discovered reserves not included), estimated a mean undiscovered resource of 21.55 MMBO, a mean of 44.76 billion cubic 

feet of (BCF) of non-associated natural gas (table 1), and a 

mean of 0.91 million barrels of natural gas liquids (MMBNGL) 

in the western Afghanistan Tirpul (AU) (80230101). The hypothetical Katawaz Basin Eocene-Miocene TPS (802401) and 

Eocene-Miocene Deltaic AU (80240101) and Helmund Basin 

Paleocene-Miocene TPS (802201) and Paleocene-Miocene AU 

(80220101) could not be adequately quantitatively assessed 

because the cumulative geologic chance or risk of discovering 

a field containing 5 MMBO or 30 BCFG or larger was less than 

10 percent and geologic data were very limited.

Reference

Drenth, B.J., and Finn, C.A., 2008, Preliminary interpretation 

of regional gravity and magnetic data over southwest Afghanistan, 

Eos Transaction of the American Geophysical Union. AGU, v. 89, 

no. 53, Fall Meeting Supplement, Abstract NS22A–02.

U.S. Geological Survey–Afghanistan Ministry of 

Mines Joint Oil and Gas Resource Assessment Team

C.J. Wandrey1 (Project Chief, cwandrey@usgs.gov), 

Amir Zada Kosti,2 Amir Mohammad Selab,2 Mohammad Karim 

Omari,2 Salam Abdul Muty,2 Haidari Gulam Nakshband,2

Abdul Hosine,2 Aminulah,2 Abdul Wahab2, Abdul Wasy Hamidi,2

Nasim Ahmadi,2 Warren F. Agena,1 Ronald R. Charpentier,1

Troy Cook,1 B. J. Drenth,1 T.R. Klett,1 Paul G. Lillis,1 Mark J. 

Pawlewicz,1 and Christopher J. Schenk.1

Further Information

Supporting geologic studies of total petroleum systems 

and assessment units and reports on the methodology used in 

the North Afghanistan petroleum resource assessment are in 

progress. Assessment results are available at the USGS Central 

Energy Team Web site: http://energy.cr.usgs.gov/oilgas.

1

 U.S. Geological Survey, Box 25046, Denver Federal Center, MS 939, 

Denver, CO 80225 U.S.A.

2

Oil and Gas Affairs, Afghanistan Ministry of Mines, Pashtoonistan Wat, 

Kabul, Afghanistan.

Total Petroleum Systems

(TPS)

and Assessment Units (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

Upper Mesozoic–Paleogene TPS

Tirpul AU 0.336 Oil 0 0 102.10 21.55 0 0 171.01 33.65 0 0 0 0

Gas 0 0 224.97 44.76 0 0 4.62 0.91

Paleocene–Miocene TPS

Paleocene–Miocene AU 0.002 Oil Not quantitatively assessed Gas

Eocene–Miocene Deltaic TPS

Eocene–Miocene Deltaic AU 0.064 Oil Not quantitatively assessed Gas

Total Conventional

Resources 21.55 78.41 0.91

Table 1. Western and Southern Afghanistan assessment results.

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

all liquids are included as NGL (natural gas liquids). Undiscovered gas resources are the sum of nonassociated and associated gas. F95 represents a 95 percent chance of at 

least the amount tabulated; other fractiles are defined similarly. AU probability is the chance of at least one accumulation of minimum size within the AU. TPS, total petroleum 

system; AU, assessment unit. Gray shading indicates not applicable]