Page 1 First Quarter 2004 Operating Results Conference Call Slides These slides should be viewed together with the Unocal 1Q 2004 Earnings News Release and related Conference Call replay at

Page 2 Forward-Looking Statements; Non-GAAP Financial Measures Unocal’s first quarter 2004 conference call presentation, including the following slides, contains forward-looking statements regarding, among other matters, expected project developments, exploratory drilling activity and dry hole costs, production rates and timing, commodity prices, future sales and transactions and expected adjusted after-tax earnings. These 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. These risks and uncertainties include, without limitation, those set forth in the related earnings news release and on pages of Unocal’s 2003 Annual Report on Form 10-K, as amended, and in subsequent reports filed by Unocal with the U.S. Securities and Exchange Commission (SEC). Unocal’s first quarter 2004 conference call presentation, including the following slides, also contains certain “non-GAAP financial measures” as defined under SEC regulations. Please refer to Unocal’s first quarter 2004 earnings news release and related quarterly fact book for a discussion of these non-GAAP financial measures, a reconciliation to the most directly comparable GAAP financial measure and other information relating thereto. The earnings news release and quarterly fact book are posted on the Unocal web site,

Page 3 Dec. 31, ,876 **1683,70854 % Dec, 31, 20033,421**4043,01746 % Mar. 31, , , % Change (615) 592 (1,207) (11) % Net Debt Reduction Since 12/31/2002 ($MM) Total Debt / Total Debt / Total Total TotalNet Capitalization DebtCash Debt * Ratio * Total debt minus cash ** Pro forma for FIN 46 FIN 46-R

Page 4 Unocal 2Q 2004 Outlook Summary Worldwide Production:410,000 – 420,000 boed EPS Adjusted after tax (diluted): $ $0.75 April 26th Analyst Mean Estimate: $0.72 Commodity Price Assumptions (NYMEX Benchmark at ) Oil: $ / bbl (WTI) Gas: $ 5.70 / mmBtu (Henry Hub) Earnings Sensitivities to Commodity Prices Oil: $8 MM change for every $1/bbl change Gas: $3 MM change for every $0.10/mmBtu change in North America realization Pretax Dry Hole Forecast: $25 - $35 MM

Page 5 Unocal 2004 Non E&P Earnings Outlook Ranges Midstream & Marketing 23 13–17 65–75 Geothermal 16 12–16 60–70 Corporate & Other Admin & General(27) (22)–(26) (95)-(100) Net Interest(32) (30)–(32) (115)-(125) Environ. & Litigation (5) (3) - (6) (18)-(24) Other (18) (20)-(25) (70)-(80) Million $ 1Q 2QE Full Year

Page 6 Unocal 2Q 2004 Material Hedge Positions* Fixed Price Gas, MMMBTU225$5.53 Oil, MBO36$31.26 CollarsCeilingFloor Gas, MMMBTU13$6.01$4.65 Oil, MBO2$28.40$24.00 Daily Volume Fixed Price * NYMEX trading closed for April & May

Page 7 Unocal 3Q 2004 Material Hedge Positions Fixed Price Gas, MMMBTU280$5.66 Oil, MBO17$ Collars CeilingFloor Oil, MBO2$28.40$24.00 Daily Volume Fixed Price

Page 8 Unocal 4Q 2004 Material Hedge Positions Fixed Price Gas, MMMBTU140$5.29 CollarsCeilingFloor Oil, MBO2$28.40$24.00 Daily Volume Fixed Price

Page 9 Reported First Quarter Special Items Gain on Sale of U. S. Assets (6)(.02) Litigation Settlement U.S. E&P (15)(.05) Sale of Geothermal Assets (21)(.08) Environmental & Litigation Unocal 1Q Reported and Adjusted Earnings $ Million$ Per Share Adjusted First Quarter

Page 10 First Quarter Fourth Quarter Increase Factors: Higher worldwide oil/liquids prices ($30.64 vs. $28.33) Higher worldwide gas prices39.14 ($4.00 vs. $3.65) Lower E&P expenses Higher Earnings from non E&P Oper Lower production volumes(25)(.09) (409 MBOE/D vs. 420 MBOE/D) Timing of Crude Oil Liftings(7)(.03) All Other9.03 Unocal Adjusted Earnings $ Million$ Per Share

Page 11 Unocal E&P United States Results 1Q 2004 vs. 4Q 2003 United States - Higher earnings21 Higher liquids prices 1 ($29.87 vs. $29.30) Higher Natural Gas Prices 33 ( $5.57 vs, $ 4.66) Lower cash expenses10 Lower production volumes(25) All Other 2 $ Million

Page 12 Unocal E&P Canada Results 1Q 2004 vs. 4Q 2003 $ Million Canada - Higher results5 Higher Prices8 Liquids ($ vs ) Gas ($ 5.08 vs, $4.34) Lower Volumes(2) Other(1)

Page 13 Unocal E&P International Results 1Q 2004 vs. 4Q 2003 International - Higher earnings37 Higher production2 Tax rate & All Other4 Higher prices16 Liquids ($31.57 vs. $28.73) Gas ($2.98 vs. $2.96) Lower Cash Expenses17 Lower Dry Hole Expense5 Timing of crude oil liftings(7) $ Million

Page 14 $ Million Unocal Non E&P Operating Segment Results 1Q 2004 vs. 4Q 2003 Non E&P - Higher earnings10 Geothermal Improved Results 4 Midstream & Marketing 6 Oil & Gas Trade Margins 3 Pipeline Results 3

Page 15 Unocal Corporate & Other Results 1Q 2004 vs. 4Q 2003 $ Million Corp. & Other - Higher expenses (1) Reclassification Of Preferred Interest (7) Other 7 All Other (1)