At year-end 2003, Unocal's preliminary estimate of worldwide reserves totaled 1,765 million BOE, off slightly from 1,774 million BOE at year-end 2002. Total production for the year was 169 million BOE.

"We were able to replace nearly all of our production plus the 98 million BOE that we sold as part of our North America restructuring program," said Charles R. Williamson, Unocal chairman and chief executive officer.

"Our portfolio of large development projects and deepwater discoveries has now progressed to a stage where we should see continuing bookings as more contracts are signed and discoveries are approved for development."

Unocal's reserve replacement performance reflects continued strength in legacy areas including Thailand, Pure Resources, Northrock Resources, and Alaska. The company also progressed in commercialising the company's large backlog of discovered oil and gas in Bangladesh and Indonesia.

During 2003, the company also added proved reserves of 203 million BOE from discoveries and extensions, including upward revisions of 43 million BOE because of reservoir performance. This was offset partially by 4 million BOE in negative price revisions attributable to changes in crude oil prices for reserves held under production-sharing contracts (PSCs).

In addition to its proved reserve base, Unocal Thailand has nearly 3 trillion cubic feet of unbooked discovered gas resources, as well as significant possible volumes.

The company also said that the 2003 reserves did not include resources from a number of previously announced major discoveries - Gehem, Gula and Gendalo in Indonesia; Vietnam; Arthit in Thailand; Bibiyana in Bangladesh; Xihu Trough in China; and the Champlain, Trident, St. Malo, and Puma deepwater GOM discoveries, which are all in active appraisal.