press release

Unocal's Spirit Energy 76 says Mad Dog appraisal well successful

Sugar Land, Texas, Feb. 7, 2000 - Unocal Corporation's Spirit Energy 76 unit today said that the appraisal well drilled on the Mad Dog prospect in Green Canyon block 782 encountered 250 feet of oil pay in zones that appear to correspond to those penetrated by the discovery well.

The appraisal well was drilled to a measured depth of 20,268 feet about 2 miles north of the discovery well. A sidetrack to the main appraisal well was drilled to 21,560 feet, and the results are under evaluation.

Unocal holds a 25-percent interest in the 2-1/2 block drilling unit that encompasses most of the Mad Dog structure. BP Amoco is operator, with a 63.56-percent interest in the well. BHP owns the remaining interest.

"These encouraging results take us an important step forward in proving the commerciality of the Mad Dog discovery," said Mike Bell, vice president of Unocal's deepwater program in the Gulf of Mexico.

Bell said that further appraisal drilling on the discovery will be required to define the size and extent of the structure and its potential volumes. After evaluation of the appraisal program, the partnership will begin work to create a development plan for the Mad Dog field.

The Mad Dog drilling unit is located in 5,000 to 7,000 feet of water in Green Canyon blocks 825, 826 and 782, about 150 miles southwest of Venice, La. The discovery well spudded in May 1998 in Green Canyon 826 and was drilled to a measured depth of 22,410 feet.

John Donohue, president of Spirit Energy, referred to Mad Dog as a "trend opening discovery for the foldbelt and subsalt play" where the company holds a considerable deepwater acreage position. He noted that Spirit Energy's leases in the region contain several other major prospects and leads that share geological characteristics similar to Mad Dog.

Beginning in mid-2000, the company plans to begin drilling some of the most promising prospects in this ultra-deep province, with the arrival of the Discoverer Spirit drillship, currently under construction in Corpus Christi, Texas.

Spirit Energy 76, Unocal's U.S. Lower 48 exploration and production unit, has major operations on the Gulf of Mexico shelf and onshore Texas and Louisiana.

Forward-looking statements regarding exploration activities and development plans in this news release are based on assumptions concerning operational, market, competitive, regulatory, environmental and other considerations. Actual results could differ materially as a result of factors discussed in Unocal's 1998 Form 10-K report filed with the Securities and Exchange Commission.

Updated: February 2000