U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2011–3155

February 2012 Printed on recycled paper

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

recoverable, conventional petroleum resources for the southern Siberian craton provinces of Russia. The mean volumes were 

estimated at 3.0 billion barrels of crude oil, 63.3 trillion cubic feet of natural gas, and 1.2 billion barrels of natural gas liquids.

World Petroleum Resources Project 

Assessment of Undiscovered Oil and Gas Resources of the Southern 

Siberian Craton (Baykit High, Nepa–Botuoba High, Angara−Lena 

Terrace, and Cis−Patom Foredeep Provinces), Russia, 2011

Introduction

The U.S. Geological Survey (USGS) estimated volumes 

of undiscovered, technically recoverable, conventional oil and 

gas resources of the Baykit High, Nepa–Botuoba High, Angara–

Lena Terrace, and Cis–Patom Foredeep Provinces in Russia. The 

assessment is part of a program to estimate petroleum resources 

Figure 1. Generalized map showing the boundaries of the Baykit High, Nepa–Botuoba High, Angara–Lena Terrace, and Cis–Patom 

Foredeep Provinces, Russia; major geologic features; centerpoints of oil and gas fields; and the location of geologic cross section A−A′

shown in figure 2. Field data from IHS Energy (2009); geologic province boundaries from Persits and others (1998) and Ulmishek (2001a, b).

for priority basins around the world, specifically for total 

petroleum systems (TPS) and assessment units (AU) that are 

defined on the basis of their geologic attributes that are favorable 

for the generation and accumulation of petroleum. The Baykit 

High Province, encompassing about 202,661 square kilometers 

(km2) (fig. 1), contains a TPS that had undergone a tectonic, and, 

presumably, a petroleum-generation history that was different 

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ANABAR-OLENEK HIGH

KEMPENDIAY

REGION

Lena-Vilyuy

Basin

Tunguska

Basin

YENISEY

RIDGE

ALTAY-SAYAN

FOLDED REGION

MONGOL-OKHOTSK

FOLDED REGION

BAIKAL-PATOM

FOLDED REGION

ALDAN SHIELD

Ulan Bator

Chatanga

RUSSIA

CHINA MONGOLIA

Irkutsk LAKE BAIKAL

ARCTIC CIRCLE

BAYKIT ARCH

KATANGA

SADDLE

Cis-Sayan Basin

ANGARA-LENA

TERRACE

NEPA-BOTUOBA ARCH

CIS-PATOM FOREDEEP

0 500 KILOMETERS

0 100 200 300 MILES

100 200 300 400

95o 100o 105o 110o 115o 120o

A'

A

70o

65o

60o

55o

50o

Province boundary

Country boundary

Oil field

Gas field

City

EXPLANATION

Location of cross section

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from the other geologic provinces and therefore the province 

was assessed separately. The Nepa–Botuoba High, Angara–Lena 

Terrace, and Cis–Patom Foredeep Provinces, however, were 

assessed collectively as one TPS and AU because of a paucity of 

data, and that the same TPS most likely spans all of the provinces. These three geologic provinces encompass a total area of 

669,137 km2 (fig. 1). This assessment was based on published 

geologic information and on commercial data from oil and gas 

wells and fields, and from field production records.

Total Petroleum Systems and Assessment Units

The Baykit High Province and the combined area of the 

Nepa–Botuoba High, Angara–Lena Terrace, and Cis–Patom 

Foredeep Provinces are interpreted to have originated as rifted 

passive margin basins, which controlled the distribution of 

upper Proterozoic source rocks, as well as the oil and gas 

resources. The rifted-passive margin basins underwent compression and deformation during the late Proterozoic (Baikalian 

orogeny) by collision of continental blocks with the Siberian 

craton and again during the late Paleozoic (Hercynian orogeny) 

by collision of the Kazakh, Siberian, and Eurasian continents 

(Ulmishek, 2001a, b).

Two TPSs were defined and called Proterozoic−Paleozoic 

Composite TPSs (table 1), one for the Baykit High Province and 

another for the Nepa–Botuoba High, Angara–Lena Terrace, and 

Cis–Patom Foredeep Provinces. They both include upper Proterozoic petroleum source rocks and upper Proterozoic through 

Cambrian reservoir rocks. One AU containing conventional 

undiscovered oil and gas resources was defined geologically 

and called Proterozoic–Paleozoic AUs, one for the Baykit High 

Province and another for the Nepa–Botuoba High, Angara–Lena 

Terrace, and Cis–Patom Foredeep Provinces (figs. 1 and 2).

Major source rocks are upper Proterozoic marine shales 

(Ulmishek, 2001a, b). Source rocks for the Baykit High Province were located in areas to the present-day west and southwest 

of the province and in depressions within the province. Source 

rocks outside the present-day province boundary were subjected 

Figure 2. Geologic cross section across the Baykit High, Nepa–Botuoba High, Angara–Lena Terrace, and Cis–Patom Foredeep Provinces, 

Russia. See figure 1 for location. From Ulmishek (2001a, modified from Gabrielyants, 1991). Cm1, Cm2, Cm3, Lower, Middle, and Upper Cambrian, 

respectively; R, Riphean; V, Vendian; Pz3, upper Paleozoic; TR, Lower Triassic. Approximate length of cross section 1,000 kilometers.

+ + +

Lower

Primarily carbonate rocks

Primarily clastic rocks

Salt

Volcanics

Deformed rocks of Baikal-Patom foldbelt

Fault

Unconformity

Crystalline basement

Well

EXPLANATION

A

WEST BAYKIT HIGH KATANGA SADDLE NEPA-BOTUOBA HIGH CIS-PATOM

FOREDEEP

A'

EAST

Upper

Lower

VENDIAN

RIPHEAN CAMBRIAN

Basement

Basement

V.-Tokhom

Omorin

Taygin

Oskobin

Vanavar

Preobrazhen

Verkhnechon

Talakan

KILOMETERS 1

1

2

3

4

5

0
to deformation and metamorphism during the Late Proterozoic 

Baikalian orogeny (850−820 Ma). The Proterozoic source rocks 

outside the province matured during the late Proterozoic, but 

the accumulations were destroyed by Baikalian deformation. 

Source rocks within the province attained maximum maturity 

during the early Paleozoic, after Early Cambrian evaporite 

deposition. Source rocks for the Nepa–Botuoba High, Angara–

Lena Terrace, and Cis–Patom Foredeep Provinces are hypothesized to have been located in areas to the present-day south and 

southeast of the provinces, in the Baikal−Patom Folded Region 

(fig. 1) (Ulmishek, 2001a). Age of maturation of these Proterozoic source rocks is unknown, but most likely occurred before 

Silurian or Devonian deformation. In all of the provinces, most 

known recoverable crude oil and natural gas accumulations 

have been discovered in upper Proterozoic carbonate and clastic 

rocks and Cambrian carbonate rocks (Ulmishek, 2001a, b). 

Lower Cambrian evaporates provide a regional seal, whereas 

other seal rocks include intraformational shales. Identified traps 

include combination structural and stratigraphic, such as pinchouts on crests of uplifts with updip seals, faulted anticlines, 

local uplifts, and reef- and carbonate-platform-associated facies.

Although a few large fields have been discovered — 

Yurubchen−Tokhom (oil), Soba (gas), and Kovyktinskoye 

(gas) — much of the Baykit High, Nepa–Botuoba High, 

Angara–Lena Terrace, and Cis–Patom Foredeep Provinces is 

unexplored. Future potential for discoveries exists in smaller 

structural and stratigraphic traps. Poor reservoir quality and the 

absence of source rocks pose challenges for the discovery of 

additional accumulations.

Assessment Results

Estimates of volumes of undiscovered technically recoverable, conventional oil and gas resources are shown in table 

1. No attempt was made to estimate economically recoverable resources because it is beyond the scope of this study. 

In summary, the estimated mean volumes of undiscovered, 

technically recoverable, conventional oil and gas resources 

for the Baykit High Province are approximately 426 million 

barrels (MMB) of crude oil, 2,071 billion cubic feet (BCF) of 

natural gas (721 BCF of associated and dissolved natural gas 

and 1,350 BCF of nonassociated natural gas), and 38 MMB of 

natural gas liquids (9 MMB of natural gas liquids in oil accumulations and 29 MMB of total liquids in nonassociated gas 

accumulations).

The estimated mean volumes of undiscovered, technically 

recoverable, conventional oil and gas resources for the Nepa–

Botuoba High, Angara–Lena Terrace, and Cis–Patom Foredeep 

Provinces are approximately 2,599 MMB of crude oil, 61,259 

BCF of natural gas (12,845 BCF of associated and dissolved 

natural gas and 48,414 BCF of nonassociated natural gas), and 

1,148 MMB of natural gas liquids (60 MMB of natural gas 

liquids in oil accumulations and 1,088 MMB of total liquids in 

nonassociated gas accumulations).

The total estimated mean volumes of undiscovered, technically recoverable, conventional oil and gas resources for all of the 

South Siberian Basin Provinces are approximately 3,025 MMB 

of crude oil, 63,330 BCF of natural gas (13,566 BCF of associated and dissolved natural gas and 49,764 BCF of nonassociated 

natural gas), and 1,186 MMB of natural gas liquids (69 MMB of 

natural gas liquids in oil accumulations and 1,117 MMB of total 

liquids in nonassociated gas accumulations).

Total undiscovered resources Total petroleum systems

(TPS)

and assessment units (AU)

Field

type

Oil (MMB) Gas (BCF) NGL (MMB)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

Mean (expected)

largest

field size

(MMB or BCF)

Gas

Oil

Proterozoic–Paleozoic AU

Baykit High Province, Proterozoic–Paleozoic Composite TPS

116 365 943 426 184 601 1,678 721 2 7 21 9

538 1,221 2,616 1,350 12 27 57 29

127

151

Gas

Oil

Proterozoic–Paleozoic AU

2,599 12,845 60

48,414 1,088

1,004 2,388 4,944 4,785 11,627 25,112 22 54 121

17,154 44,205 94,321 361 961 2,264

Total undiscovered petroleum

resources 3,025 63,330 1,186

531

11,213

Nepa-Botuoba High, Angara–Lena Terrace, and Cis–Patom Foredeep Provinces, Proterozoic–Paleozoic Composite TPS

Table 1. Southern Siberian craton assessment results (undiscovered, technically recoverable, conventional resources).

[MMB, million barrels; BCF, billion cubic feet. Results shown are fully risked estimates. For gas fields, all liquids are included under the natural gas liquids 

(NGL) category. F95 denotes 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. TPS, total petroleum system; AU, assessment unit. Gray shading indicates not applicable]
References Cited

Gabrielyants, G.A., ed., 1991, Regional geology of petroleum 

provinces of the USSR (Regionalnaya Geologiya neftegazonosnykh territoriy SSSR): Moscow, Nedra, 284 p.

IHS Energy, 2009 [includes data current through October 2009], 

International exploration and production database: Englewood, Colo., IHS Energy.

Persits, F.M., Ulmishek, G.F., and Steinshouer, D.W., 1998, 

Map showing geology, oil and gas fields, and geologic provinces of the former Soviet Union: U.S. Geological Survey 

Open-File Report 97–470E, CD–ROM.

Ulmishek, G.F., 2001a, Petroleum geology and resources of the 

Nepa−Botuoba High, Angara−Lena Terrace, and Cis−Patom 

Foredeep, southeastern Siberian craton, Russia: U.S. Geological Survey Bulletin 2201−C, 16 p.

Ulmishek, G.F., 2001b, Petroleum geology and resources of the 

Baykit High Province, East Siberia, Russia: U.S. Geological 

Survey Bulletin 2201−F, 18 p.

For Further Information

Supporting geologic studies of total petroleum systems and 

assessment units, reports on the methodology used in the assessment of the Baykit High Province and Nepa–Botuoba High, 

Angara–Lena Terrace, and Cis–Patom Foredeep Provinces, and 

assessment results are available at the USGS Central Energy 

Resources Science Center website: http://energy.usgs.gov.

South Siberian Basin Provinces Assessment Team

T.R. Klett (tklett@usgs.gov), Christopher J. Schenk, Craig J. 

Wandrey, Ronald R. Charpentier, Michael E. Brownfield, 

Janet K. Pitman, Richard M. Pollastro, Troy A. Cook, and 

Marilyn E. Tennyson.