Though these western areas have been the main focus of the country's petroleum activities, explorers have searched for giant accumulations in eastern Indonesia for more than a century.

Phillips, Conoco, Total and Occidental subsequently tried to emulate Trend's success by exploring the adjacent Bintuni Basin, but found only about 3 million barrels (480 thousand cubic metres), shallow onshore oil field called Wiriagar in 1981 and some uneconomic offshore gas in the early 1990s.

Arco entered Irian Jaya in 1989 by farming into a Conoco-led partnership holding an onshore block called KBSA on the northern side of Berau Bay.

Two dry holes were drilled in 1990, and Arco faced a decision -- to drop out of the Production Sharing Contract (PSC) and exit Irian Jaya, or to continue exploration in the Bintuni Basin.

After a long and thorough discussion, Marlan finally agreed that the team should proceed with a direct negotiation with Pertamina, the Indonesian Oil and Gas State Company for a new Wiriagar PSC, after Conoco relinquished their KBSA block.

The main purpose of the presentation was to provide an explanation to Pertamina on Arco’s interest in acquiring a new Wiriagar PSC within the ex-Conoco's KBSA block.

The team showed the proposed location of the Wiriagar PSC as well as the main target of the deeper Jurassic sandstone reservoir.

Stephen Scott, a staff geophysicist who joined the New Venture team in late 1994 provided seismic interpretations both for the onshore Wiriagar and the offshore Bintuni Bay, which were used to finalize the appraisal well location and to refine the regional understanding of the area.

The pressure analyses of the WD-1 well, conducted by Larry Casarta and John Marcou, Petroleum Engineer in the team, indicated that the gas accumulation in Wiriagar Deep extends southward to the offshore Occidental's Berau Block.

The New Venture team continued to work studying the regional geology and evaluating block opportunities in the focus areas of Eastern Indonesia and NW Australian Shelf.

Arco was unwilling to carry the other partners in a deep test despite the attraction of retaining KBSA's sunk cost pool, and no deal was reached among the group.

Brad Sinex at Arco International's headquarters in Plano, Texas, took charge of the negotiations with Occidental and worked a farm-in to the Berau Block aided by Thorkild Juul-Dam in Jakarta.

In addition to producing the maps on which the Wiriagar Deep appraisal locations were selected, Scott worked with Casarta and Sampurno to refine the regional geological picture.

Scott put all the regional data together, and conceived that the closures could be part of one large anticline parallel to and immediately east of the Wiriagar fold.

Vorwata had a potential technical problem: At Jurassic level, it was several thousand feet deeper than the Wiriagar anticline, and generally accepted wisdom was that porosity would be low and reservoir quality poor.

Recognizing that there might be a more optimistic scenario for Vorwata Jurassic reservoir quality, Duncan consulted with Alton Brown of Arco's geoscience technology group in Plano.

Brown analyzed burial history, facies controls and diagenesis, and concluded that conventional wisdom was wrong and reservoir quality would be fine.