LASMO Announces Two New Gas Discoveries in Indonesia.

Business Editors

LONDON--(BUSINESS WIRE)--May 5, 2000

LASMO plc (NYSE: LSO), the international oil and gas exploration and production company, today announced that gas has been discovered in both the Gada and Gula prospects in the Ganal Production Sharing Contract (PSC) area, offshore East Kalimantan, Indonesia.

The operator, Unocal, estimates that together the gross potential in the structures will be in the 2 to 3 TCF range, but more drilling will be necessary to assess the full resource potential of the prospects.

The Gula discovery is located 35 miles north of the earlier Gendalo discovery and the Gada discovery is located 8 miles north of the Gula 1 well. The Gula 1 well drilled to a depth of 16,182 feet in 6,051 feet of water, and the Gada 2 well was drilled to a depth of 15,223 feet in 6,224 feet of water. The Gula 1 well reached total depth in a gas sand and encountered over 260 feet of net gas pay. The Gada 2 well encountered 70 feet of net gas pay. Future drilling will test the deeper section in both structures and should increase the resource potential.

These discoveries confirm that the well-defined Central Delta Play contains world-class gas resources. Several large prospects remain undrilled in the play trend. The partnership has now drilled four straight discoveries in the Central Delta Play fairway.

David Thomas, Group General Manager, Operations, commented:

"Following the earlier Gendalo discovery, these latest results confirm the significance of the deepwater Kutei basin. We have an exciting exploration program in Indonesia this year, and are pleased with the success to date."

Notes for editors

LASMO's exploration acreage in Indonesia covers 6 PSCs:

-- 20 percent interest in Ganal and Sesulu (Unocal, operator, 80 percent) and
10 percent interest in Rapak (Unocal operator 60 percent, Mobil 30 percent) in
the Kutei Basin

-- 100 percent interest in Krueng Mane (LASMO operator), offshore Sumatra

-- 60 percent interest in Malagot, onshore Irian Jaya

-- 12.5 percent interest in the Shell operated Bukat PSC in the Tarakan Basin
and awaiting Government approval to join Shell with a 12.5% in the Ambalat PSC

Gas from the Ganal PSC is expected to be marketed via the Bontang LNG plant, the world's largest, which supplies LNG to Japan, Korea and Taiwan.

LASMO's shares trade on the London and New York Stock Exchanges. Shares are quoted on the SEAQ System, and prices may be accessed on the Reuter Equities 2000 Service under the symbol LSMR.L and on Quotron under the symbol LSMRU.EU. For further information, visit LASMO's web page at http:\\www.lasmo.com.