Coal bed methane for the future of gas reserves in Indonesia is one topic explained in BUMI Bulletin published by SKK Migas (Indonesia Special Task Force for Oil and Gas). This topic is very interesting because I never considered coal bed methane (CBM) as source of gas until now. CBM is hydrocarbon formed and kept in source rock, it does not move or migrate. In Indonesia, CBM reservoir is very wide and its resource and reserve is large.
To exploit CBM, we need special method which is different from conventional oil and gas exploitation. To get CBM, we need fracturing for dewatering, so that the gas is taken.
Prospect of Coal Bed Methane
Utilization of coal as coal bed methane is conducted when location of coal is too deep. Ideal depth of coal so that it produces high quality gas is between 500-1000 meter.
Coal bed methane has unique characteristics that make it different from conventional gas. It has low production rate, but longer production period. The production period can be as long as 20 years. Investment for coal bed methane is approximately 10% of investment of conventional gas. However, coal bed methane needs many development wells. In conclusion, coal bed methane has excellent economic value for long period.
Based on data from SKK Migas in 2016, potential of CBM in existing working area, which is in South Sumatera is 31.57 trillion cubic feet (Tcf) from 19 working areas and in East Kalimantan which is 58.61 Tcf from 27 working areas.
Based on result of CBM drilling, ranking of the best CBM is:
- South Sumatera basin, especially in Tanjung Enim dan Muara Enim
- Barito East Kalimantan basin
- Kutai East Kalimantan basin, especially in Sanggata
In Sumatera area, cost of exploration is between US$ 1 million – US$ 1.8 million per well. While in Kalimantan area, the cost is between US$ 1.2 million – US$ 4.2 million per well.
Challenge in Coal Bed Methane Development
Since 2008, there are 54 coal bed methane PSCs (Production Sharing Contract) awarded in Indonesia. 22 PSCs in Sumatera and 32 PCSs in Kalimantan. However, only 4 PSCs in Sumatera that already in production test single well stage, and 4 PSCs in Kalimantan. This indicates that exploration process is not maximal yet.
There are several challenges in coal bed methane development in Indonesia. First, PSCs do not understand enough about Indonesia coal characteristics which is different from other countries, especially in well design and completion. Second, coal bed methane is still under oil and gas conventional. The impact is status of coal bed methane is still equated with conventional oil and gas.
Challenge in Coal Bed Methane Development
At the moment, there is one PSC that is in process of coal bed methane POD to the ministry of energy and mineral resources, which is PSC GMB Tanjung Enim, operated by KKKS Dart Energy. The POD covers Tanjung Enim Area A, Area B, Muara Enim Formation, and South Sumatera Basin. Reserve of this CBM is 127.93 BSCF.
That’s all I want to share. I hope I can share you more about this topic, for example existing CBM facilities and its technologies.
References:
[1] BUMI Buletin SKK Migas #66 Oktober 2018 (https://skkmigas.go.id)
[2] Laporan tahunan 2017 SKK Migas (https://skkmigas.go.id)