Chevron Australia Pty Ltd, a unit of Chevron Corp, said yesterday it had made a fifth gas discovery from its drilling programme in offshore permit area WA-267-P, adjacent to the major Gorgon gas field.
Chevron acting managing director Keli Taureka said the size and gas quality of the Io-1 wildcat well was yet to be determined, but it added significantly to the already substantial Greater Gorgon fields' reserves, offshore northwest Australia. The well follows the Geryon-1, Orthrus-1, Urania-1 and Maenad-1 discoveries in the deepwater permit west of Gorgon, which is targeted to underpin future liquefied natural gas exports and domestic gas supplies.

Chevron said the Greater Gorgon gas fields, excluding the discoveries in WA- 267-P contained 17.6 trillion cubic feet at the proven and probable level and 21.5 tcf at the possible level.The Gorgon field itself which is a joint venture of Chevron, and local units of Exxon Mobil Corp, Texaco Inc and Royal Dutch/Shell contains 13.8 tcf.Chevron has still to release any figures on estimated gas reserves in WA-267-P. A Chevron spokeswoman said the company was excited about the results of the drilling programme."It has been very successful and we are pleased with Chevron's success rate," she said.

A sixth well, Callirhoe, was due to be spudded on Thursday or Friday. Io-1 was drilled about 210 km north-northwest of Onslow and 65 km to the northwest of the Gorgon gas field, in 1,352 metres of water. It reached a total depth of 3,030 metres on January 14 and encountered a gas-bearing zone in the lower part of the well. Chevron and Texaco each have a 25 per cent stake in WA-267-P, with the remainder split equally between Exxon Mobil, Shell and BP Amoco Plc. Shell's plans to integrate the Gorgon gas reserves with the North West Shelf to underpin expansion of LNG exports have been a key reason behind the energy giant's bid to control Woodside Petroleum Ltd.

Woodside is operator and an equal one-sixth stake-holder in the North West Shelf, but has no equity in Gorgon. Shell is seeking to lift its stake in Woodside to 56 per cent from 34 per cent through a cash offer of A$14.80 and a call option, followed by an assets for shares swap.