National and Global Petroleum Assessment

Assessment of Coalbed Gas Resources in the Kutei 

and Barito Basin Provinces, Indonesia, 2018

Figure 1. Map showing the two coalbed gas assessment units (AUs) in 

the Kutei and Barito Basin Provinces of Indonesia. Province boundaries 

are from Klett and others, 1997. 

BARITO

BASIN

KUTEI

BASIN

INDONESIA

INDONESIA

MALAYSIA

JAVA SEA

MAKASSAR STRAIT

112° E 113° E 114° E 115° E 116° E 117° E 118° E 119° E

2° N

1° N

0°

1° S

2° S

3° S

4° S

5° S

0

0 50 100 KILOMETERS

50 100 MILES

Base map from U.S. Department of the Interior National Park Service

AUS

IDN IDN

TLS

MYS

SGP MYS

BRN PHL THA SOUTH

CHINA

SEA

TIMOR SEA

INDIAN

OCEAN

Map

area

EXPLANATION

Barito Neogene Coalbed Gas AU

Province boundary

Kutei Neogene Coalbed Gas AU

Introduction

The U.S. Geological Survey (USGS) quantitatively assessed the 

potential for undiscovered, technically recoverable continuous (unconventional) coalbed gas resources in the Kutei and Barito Basin Provinces of 

Indonesia (fig. 1). Miocene coals in the Kutei and Barito Basin Provinces 

form part of a regressive clastic wedge sourced from uplifted areas in 

western Borneo (Moss and Chambers, 1999; Witts and others, 2011). 

Clastic sediments of this wedge prograded to the east and southeast within 

fluvial-deltaic and marginal marine environments with extensive coals 

(Paterson and others, 1997; Davis and others, 2007; Widodo and others, 

2010). The extent, thickness, and thermal maturation of coals have been 

documented in both basins (Adhi and others, 2004; Sapiie and others, 2014; 

Friederich and others, 2016; Putra and others, 2016). Drilling and testing 

for coalbed gas has occurred in the Barito Basin Province, where coals 

of the Miocene Warukin Formation are the primary exploration target 

(De Man and others, 2012; Putra and others, 2016). The primary 

coalbed gas reservoirs in the Kutei Basin are coals of the Miocene 

Balikpapan Formation (Satyana and others, 1999; Pramudhita and 

others, 2009), which have not been drilled or tested to the extent of 

Warukin coals in the Barito Basin.

Total Petroleum Systems and Assessment Units

For potential coalbed gas resources in the Kutei Basin Province, 

the USGS defined a Kutei Neogene Coal Total Petroleum System 

(TPS) and Kutei Neogene Coalbed Gas Assessment Unit (AU) within 

this TPS. The Barito Neogene Coal TPS was defined in the Barito 

Basin Province with a Barito Neogene Coalbed Gas AU. Shallow 

Neogene coals in both basins are generally thermally immature with 

vitrinite reflectance of less than 0.5 percent (Haris and others, 2010), 

contain Type III kerogen, have hydrogen index values of as much as 

260 milligrams of hydrocarbon per gram of organic carbon, and have 

net coal thickness of as much as 60 meters (Davis and others, 2007). 

The geologic model for this assessment is similar for coalbed gas 

accumulations in both the Kutei and Barito Basin Provinces. Coals 

of the Neogene regressive clastic wedge were deposited across large 

areas of both basins. Shallow burial generally left the coals thermally 

immature with respect to gas generation. However, bacterial activity 

acting on shallow coals produced biogenic gas, which was adsorbed 

and retained within the coal cleat systems (De Man and others, 2012). 

The geologic model for both TPSs includes the possibility that some 

thermogenic gas is present within the deeper, more thermally mature 

Neogene coals (Haris and others, 2010). Vertical wells were used in 

the modeling of potential coalbed gas resources.

Assessment input data are summarized in table 1. Input data for 

drainage areas, success ratios, and estimated ultimate recoveries are 

taken from geologic analogs in the United States, particularly the coals 

in the Powder River Basin (Flores, 2004).

Undiscovered Resources Summary

The USGS quantitatively assessed coalbed gas resources 

in two assessment units (table 2) in the Kutei and Barito Basin 

Provinces of Indonesia. For undiscovered, technically recoverable coalbed 

gas resources, the mean totals are 10,738 billion cubic feet of gas (BCFG), 

or 10.7 trillion cubic feet of gas, with an F95–F5 fractile range 

from 2,525 to 22,759 BCFG. Of the mean total of 10,738 BCFG 

(coalbed), 6,753 BCFG, or 63 percent, is estimated to be in the Kutei 

Neogene Coalbed Gas AU, and 3,985 BCFG (coalbed), or 37 percent, 

is estimated to be in the Barito Neogene Coalbed Gas AU.

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2018–3055

November 2018

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

resources of 10.7 trillion cubic feet of potential coalbed gas resources in the Kutei and Barito Basin Provinces of Indonesia.
References Cited

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R., comps., 2004, National resources and reserves of mineral, coal, and geothermal: 

Indonesian Directorate General of Geology and Mineral Resources, Special Publication 

No. 103, 130 p.

Davis, R.C., Noon, S.W., and Harrington, J., 2007, The petroleum potential of Tertiary coals 

from western Indonesia—Relationship to mire type and sequence stratigraphic setting: 

International Journal of Coal Geology, v. 70, nos. 1–3, p. 35–52.

De Man, E., Gantyno, A., Huang, S., Petersen, K., Saferi, E., Widiarti, R., Wertanen, S., 

and Rahardjanto, S., 2012, CBM operational lessons learned—Barito Basin, Indonesia, 

in 36th Annual Convention of the Indonesian Petroleum Association, Jakarta, Indonesia, 

May 23–25, 2012, Proceedings: Indonesian Petroleum Association, Paper IPA12-E-194, 20 p.

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and Montana: U.S. Geological Survey Digital Data Series DDS–69–C, 1 CD–ROM.

Friederich, M.C., Moore, T.A., and Flores, R.M., 2016, A regional review and new insights 

into SE Asian Cenozoic coal-bearing sediments—Why does Indonesia have such extensive coal deposits?: International Journal of Coal Geology, v. 166, p. 2–35.

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potential of Bentian Besar, Kutei Basin, in 34th Annual Convention and Exhibition, 

Jakarta, Indonesia, May 18–20, 2010, Proceedings: Indonesian Petroleum Association, 

Paper IPA10-G-139, 10 p.

Klett, T.R., Ahlbrandt, T.S., Schmoker, J.W., and Dolton, G.L., 1997, Ranking of the world’s 

oil and gas provinces by known petroleum volumes: U.S. Geological Survey Open-File 

Report 97–463, 1 CD–ROM. 

Moss, S.J., and Chambers, J.L.C., 1999, Tertiary facies architecture in the Kutai Basin, Kalimantan, Indonesia: Journal of Asian Earth Sciences, v. 17, nos. 1–2, p. 157–181.

Paterson, D.W., Bachtiar, A., Bates, J.A., Moon, J.A., and Surdam, R.C., 1997, Petroleum 

system of the Kutei Basin, Kalimantan, Indonesia, in Conference on Petroleum Systems 

of SE Asia and Australasia, Jakarta, Indonesia, May 21–23, 1997, Proceedings: Indonesian Petroleum Association, Paper IPA97-OR-35, p. 709–726.

Pramudhita, B.A.; Siregar, B.S.A.; Tanjung, H.; Faris, M.; Indrajaya, R.; Satrio; and Kambu, 

Y., 2009, Palynology analysis and coal characterization—A preliminary study for 

CBM prospectivity of Balikpapan Formation, Kutei Basin, in 33rd Annual Convention of the Indonesian Petroleum Association 2009, Jakarta, Indonesia, May 5–7, 2009, 

Proceedings: Indonesian Petroleum Association, Paper IPA-SG-040, 10 p.

Putra, R.R., Larasati, D., Ardi, S., Fiqih, F.M., Ramdani, H., Widarto, D., Guntoro, A., and 

Usman, A., 2016, Fault facies identification to determine optimum coal cleat occurence 

[sic] as coal bed methane reservoir potential, case studies—Warukin coal bearing formation (WCBF), Barito Basin, south Kalimantan, Indonesia, in Unconventional Resources 

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Exploration Geophysicists, American Association of Petroleum Geologists, Society of 

Petroleum Engineers, URTeC 2460930, 17 p., accessed May 17, 2018, at http://archives.

datapages.com/data/urtec/2016/2460930.pdf.

Sapiie, B., Rifiyanto, A., and Perdana, L.A., 2014, Cleats analysis and CBM potential of the 

Barito Basin, south Kalimantan, Indonesia: American Association of Petroleum Geologists, Search and Discovery Article No. 10653, 19 p., accessed May 17, 2018, at http://

www.searchanddiscovery.com/pdfz/documents/2014/10653sapiie/ndx_sapiie.pdf.html. 

Satyana, A.H., Nugroho, D., and Surantoko, I., 1999, Tectonic controls on the hydrocarbon 

habitats of the Barito, Kutei, and Tarakan Basins, eastern Kalimantan, Indonesia—Major 

dissimilarities in adjoining basins: Journal of Asian Earth Sciences, v. 17, nos. 1–2, p. 99–122.

Widodo, S., Oschmann, W., Bechtel, A., Sachsenhofer, R.F., Anggayana, K., and Puettmann, 

W., 2010, Distribution of sulfur and pyrite in coal seams from Kutai Basin (East Kalimantan, Indonesia)—Implications for paleoenvironmental conditions: International Journal of 

Coal Geology, v. 81, no. 3, p. 151–162.

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Table 1. Key input data for two coalbed gas assessment units (AUs) in the Kutei and Barito Basin Provinces of Indonesia.

[%, percent; EUR, estimated ultimate recovery per well; BCFG, billion cubic feet of gas. Well drainage area, success ratio, and EUR are defined partly using U.S. 

coalbed gas analogs. Shading indicates not applicable]

Assessment input data—Continuous AU Kutei Neogene Coalbed Gas AU

Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 800 5,121,000 10,242,000 5,121,267

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

Success ratio (%) 10 50 90 50

Average EUR (BCFG) 0.08 0.2 0.35 0.206

AU probability 1.0

Assessment input data—Continuous AU Barito Neogene Coalbed Gas AU

Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 800 3,032,500 6,065,000 3,032,767

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

Success ratio (%) 10 50 90 50

Average EUR (BCFG) 0.08 0.2 0.35 0.206

AU probability 1.0

Table 2. Results for two coalbed gas assessment units (AUs) in the Kutei and Barito Basin Provinces of Indonesia.

[BCFG, billion cubic feet of gas; NGL, natural gas liquids; MMBNGL, million barrels of natural gas liquids. Results shown are fully risked estimates. 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 systems

and assessment units (AUs)

AU

probability

Accumulation 

type

Total undiscovered resources

Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean

Kutei Neogene Coal Total Petroleum System

Kutei Neogene Coalbed Gas AU 1.0 Coalbed gas 1,596 6,049 14,323 6,753 0 0 0 0

Barito Neogene Coal Total Petroleum System

Barito Neogene Coalbed Gas AU 1.0 Coalbed gas 929 3,573 8,436 3,985 0 0 0 0

Total undiscovered continuous resources 2,525 9,622 22,759 10,738 0 0 0 0

Assessment Team

Christopher J. Schenk, Tracey J. Mercier, Phuong A. Le, Marilyn E. Tennyson, 

Thomas M. Finn, Michael E. Brownfield, Kristen R. Marra, Stephanie B. Gaswirth, 

Heidi M. Leathers-Miller, Janet K. Pitman, and Ronald M. Drake II

For More Information

Assessment results are also available at the USGS Energy Resources 

Program website at https://energy.usgs.gov.

ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20183055