press release

Unocal announces results of Dendara GOM exploration well

Sugar Land, Texas, March 5, 2001 - Unocal Corporation (NYSE: UCL) today said that it has concluded drilling operations on its Dendara deepwater exploratory well in the Gulf of Mexico on Green Canyon block 785.

The Dendara well reached its objectives and encountered hydrocarbon-bearing sands that do not contain commercial quantities of hydrocarbons. The company has completed the collection and evaluation of the well data and has plugged and abandoned the well.

The Dendara well was drilled in 7,200 feet of water to a total measured depth of 24,050 feet in 49 days at an estimated gross cost of $22 million. Unocal expects to record its net share -- $17 million pretax -- as a dry hole charge in the first quarter.

"Exploration has inherent risks. Dendara was a quality prospect, but it did not come in as a discovery. We still have a number of world-class exploration prospects remaining in our deepwater Gulf of Mexico inventory, and we are eager to move on to our next prospect," said Mike Bell, vice president of Unocal Deepwater USA.

Unocal holds a 75-percent working interest in the Dendara well; its co-venturers are Nexen Petroleum USA, Inc., and TotalFinaElf E&P USA, Inc. (a subsidiary of TotalFinaElf S.A.), each with a 12.5-percent interest.

This news release contains certain forward-looking statements about Unocal's future exploration activities and expected dry hole costs. These statements are not guarantees of future performance. The statements are based upon Unocal's current expectations and beliefs and are subject to a number of known and unknown risks and uncertainties that could cause actual results to differ materially from those described in the forward looking statements. Actual results could differ materially as a result of factors discussed in Unocal's 1999 Form 10-K and other reports report filed with the SEC. Unocal undertakes no obligation to update the information in this news release.

Updated: March 2001