INDONESIA - Reserves.

There have been varied estimates of proven oil reserves in Indonesia. A highly reliable and independent APS source says the proven oil reserves at end-2004 were 4.2 bn barrels. The latest estimate by the BP Statistical Review of World Energy, June 2004, put the proven reserves by end-2003 at 4.4 bn barrels, down from 5.2 bn barrels at end-1993 and 10.1 bn barrels at end 1983. Some recent estimates have put Indonesia's proven reserves at 4.7 bn barrels (see background in Vol. 60, No. 9).

Indonesian crude oils vary widely in quality, with most streams having gravities in the 22[degrees] to 37[degrees] API range. Indonesia's two main export crudes are Sumatra Light, or Minas, with a 35[degrees] API gravity, and the heavier, 22[degrees] API Duri crude.

A study released in August 2002 by Indonesia's E&P regulator, the Energy Ministry's Directorate General of Oil and Gas (BPMigas) shows that oil reserves in the Cepu block alone, located in Central/East Java, are close to 600m barrels - with about half considered recoverable.

Sizable, but as of yet unproven, oil reserves may lie in the numerous, geologically complex, pre-tertiary basins located in eastern Indonesia. These regions are much more remote and the terrain more difficult to explore than areas of western and central Indonesia.

The Energy Ministry's Director for Natural Gas Novian Thaib was on Jan. 31, 2005, quoted by The Jakarta Post newspaper as saying Indonesia's gas reserves had risen by 7.45 TCF to 188.34 TCF thanks to new discoveries in new sites or existing fields. Novian said new gas reserves had been discovered during exploration in a number of fields across the country, adding: "With the new findings, gas reserves in the country stand at 188.34 TCF". He did not provide details, saying the data were still being drawn up by the ministry.

BPMigas Deputy Director for Planning Zanial Achmad said among the revised gas reserves was the Masela field in Maluku province, operated by Inpex Corp. of Japan. He said: "It is not a new gas field, but we have found substantial additional reserves other than that which we certified". In the certification process, he said, it was calculated that the field contained some 6.7 TCF of reserves. However, the amount increased to 10 TCF based on a recent observation. Although its reserves are still largely untapped due to limited supporting infrastructure, Indonesia is known to have one of the most extensive gas reserves in the world.

The new finds exclude the one in the Jeruk field, where Australia-based oil and gas company Santos reportedly found a new huge reserve. Kardaya Warnika, another deputy director of BPMigas, earlier said Santos was currently verifying the finds to determine the exact amount of oil and gas reserves in the field. The three largest natural gas fields in Indonesia are Arun in Aceh, Bontang in East Kalimantan and Tangguh in Papua (see background in Vol. 60, Gas Market Trends 9).