INDONESIA - Papua.

The main plays in this frontier province discovered so far are in the West Irian region now called Papua. They include the Tertiary pinnacle reef play located on the western Vogelkop peninsula, and the offshore Roabiba discovery made by Occidental Petroleum (Oxy). The area was a major oil producer in the past.

In 1995 a giant gas field, Wiriagar Deep, was found by Atlantic Richfield (Arco - now part of BP). The gas lies in a Pre-Tertiary Fm. BP says the field contains more than 18 TCF, of which a large portion will be recoverable, and is hoping to find additional gas reserves in the region. The field lies in the west of Papua.

In 1994, KUFPEC of Kuwait made a major oil discovery in a Pre-Tertiary formation on the island of Ceram, in the west of Papua. The company's wildcat resulted in a 6,800 b/d flow of oil, which was the highest of any oil exploration rate in Indonesia during the previous two years.

In March 1996, Santa Fe Salawati announced the discovery of gas in its Papua block of Salawati. Its SW0-1 wildcat tested 12.5 MCF/d of gas and over 3,500 b/d of oil. But the oil reservoir is said to be small.

Exploration remains in its infancy in the difficult mountainous region in the east of Papua. So far there has been no evidence that the Mesozoic oil play of the adjacent Papua New Guinea extends west into Papua. However, a deep wildcat drilled beneath a small Tertiary reef field in Papua was reported in 1994 to have reached large quantities of gas in sandstones.

The Natuna Sea, in the South China Sea, is a large shelfal area extending as a northern salient between East and West Malaysia. It contains a number of islands. The western Natuna Sea has a small number of oil and gas fields in Tertiary clastics which are part of the south-easterly extension of the Malay Basin.

The eastern Natuna Sea contains a Tertiary limestone play with reefal limestones built up on a carbonate shelf sealed by shales. One of the world's largest gas fields was discovered there in 1973 by Agip. This is to be developed by ExxonMobil, in the most expensive gas project in the world. Moveable gas in this field, called L, is estimated at 210 TCF. But 71% of this is unwanted CO2, a greenhouse gas associated with global warming. ExxonMobil will be developing the field for a giant LNG project, with the CO2 to be reinjected into the same carbonate reservoir but beyond the limits of the producing structure.

Other Provinces: In addition to the above zones, there are interesting new discoveries in the Timor Sea, where big oil and gas discoveries have been made. But more of these will be part of East Timor, now an independent state, and Australia (see Vol. 52).

There are gas deposits on the island of Sulawesi. A discovery was made in a reefal play which raised possibilities of future prospects in the complex area of the Banda Arc, lying between Sulawesi and Papua. There is a small oil province in southern Kalimantan. In recent years, oil exploration of the Meratus Basin, in Central Kalimantan, was curtailed.

Exploration in the marine areas to the south-west and south of Sumatra and Java which overlie the fore arc basins, productive in Burma, has resulted in some small gas discoveries and dry holes. Deep water prospects, considered highly speculative as a drilling campaign in the Lombok Strait was unsuccessful, are now becoming popular following discoveries in recent years (see Part 2).