press release

Unocal adds GOM leases in OCS sale

Sugar Land, Texas, March 20, 2003 - Unocal Corporation (NYSE: UCL) today said that its Gulf Region USA and Deepwater USA business units are the apparent high bidders for interests in 27 tracts in the Central Gulf of Mexico OCS Lease Sale No. 185 conducted Wednesday by the U.S. Minerals Management Service (MMS).

The company and its co-bidders submitted apparent high bids amounting to approximately $39.5 million ($18.7 million Unocal net) on 8 shelf leases and 19 deepwater leases. (See table for detailed bid information).

Ken Butler, vice president for Unocal Gulf Region USA, said that the tracts leased during this sale will augment both the deep shelf and conventional drill site portfolio and add to the 2003 and 2004 drilling programs. "Both the deep shelf and conventional prospects targets play to Unocal's proven operating strengths and extensive infrastructure in the Gulf of Mexico," Butler said. Mike Bell, vice president of Unocal Deepwater USA commented that the lease sale results would add to Unocal's acreage position in a highly prospective region of the Gulf.

Unocal, through its Deepwater USA and Gulf Region USA business units, held an interest in 531 Gulf of Mexico leases. Of that total, 237 exploratory leases are located in deep water, while another 129 exploratory leases are on the shelf. Unocal Gulf Region USA also has 165 development leases on the GOM shelf. Leases associated with Gulf Region USA include offshore holdings of Pure Resources, Inc., which is now a wholly owned subsidiary of Unocal.

The results of Sale 185 will bring the Unocal business units' combined portfolio to 558 OCS leases in the Gulf of Mexico, if all bids are approved by the MMS.

About Unocal Corporation

Unocal is one of the world's leading independent natural gas and crude oil exploration and production companies. The company's principal operations are in North America and Asia.

* * * * * Central Gulf of Mexico Lease Sale No. 185 - March 19, 2003 Apparent High Bids by Unocal

Area/Block Unocal WI Gross Bid Net Bid
Eugene Island Block 38 100% $1,111,111 $1,111,111.00
Green Canyon Block 223 50% $305,500 $152,750.00
Green Canyon Block 232 33.3334% $564,480 $188,160.38
Green Canyon Block 266 33.3334% $2,100,700 $700,234.73
Green Canyon Block 267 33.3334% $1,347,840 $449,280.90
Green Canyon Block 276 33.3334% $570,240 $190,080.38
Green Canyon Block 310 33.3334% $315,076 $105,025.54
Green Canyon Block 319 33.3334% $293,760 $97,920.20
Green Canyon Block 320 33.3334% $7,350,000 $2,450,004.90
Green Canyon Block 364 33.3334% $7,076,000 $2,358,671.38
Green Canyon Block 408 33.3334% $437,760 $145,920.29
Green Canyon Block 543 33.3334% $414,720 $138,240.28
Green Canyon Block 583 33.3334% $2,800,500 $933,501.87
Green Canyon Block 587 33.3334% $414,720 $138,240.28
Green Canyon Block 627 33.3334% $5,125,000 $1,708,336.75
Green Canyon Block 628 33.3334% $1,280.000 $426,667.52
Green Canyon Block 631 33.3334% $315,076 $105,025.54
Green Canyon Block 947 100% $4,005,760 $4,005,760.00
Mississippi Canyon Block 970 50% $378,000 $189,000.00
Mississippi Canyon Block 971 50% $378,000 $189,000.00
S Marsh Island Block 67 100% $221,385 $221,385
S Marsh Island, S Add Block 120 100% $78,245 $78,245.00
Ship Shoal Block 200 100% $251,725 $251,725.00
Ship Shoal Block 210 100% $502,943 $502,943.00
S Timbalier, S Add Block 213 100% $443,852 $443,852.00
Vermilion Block 11 100% $217,451 $217,451.00
W Cameron Block 22 100% $1,211,423 $1,211,423.00
TOTALS $39,511,267 $18,709,955.94

Updated: March 2003