The original estimates for the field, in the offshore Carnarvon Basin, Western Australia, were 400 Bcf until the results from the John Brookes-2 appraisal well.

In addition to the reserves upgrade, the partners inked a deal to sell almost half of the John Brookes gas, at 20 million cubic feet (MMcf) of gas per day, to Newcrest Mining over the next 15 years, bringing the total gross reserves dedicated and booked to approximately 350 Bcf at year-end 2003. Apache expects first sales under the contract by the fourth quarter of 2004.

The discovery well, John Brookes-1, was drilled in late 1998 and encountered a 311-foot gross (262-foot net) gas column between 9,115 feet and 9,426 feet in the Cretaceous-age Barrow sandstone group.

Two zones were tested, flowing at a combined rate of 54 million cubic feet (MMcf) of gas and 274 barrels of condensate per day. The Thomas Bright-2 appraisal well, drilled in early December 2003, and Thomas Bright-1, drilled in March 2003, are in the same reservoir with consistent gas-water contacts.

"Over the last two years we have increased our interest to 55% from our original 20% and taken over operatorship," said Apache president and chief executive officer G. Steven Farris. Santos holds the remaining 45% interest.