1. 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 www.unocal.com

2. 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 56-65 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, www.unocal.com.

3. Page 3 Dec. 31, 2002 3,876 **1683,70854 % Dec, 31, 20033,421**4043,01746 % Mar. 31, 2004 3,261 760 2,501 43 % 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

4. Page 4 Unocal 2Q 2004 Outlook Summary Worldwide Production:410,000 – 420,000 boed EPS Adjusted after tax (diluted): $0.65 - $0.75 April 26th Analyst Mean Estimate: $0.72 Commodity Price Assumptions (NYMEX Benchmark at 4-22-2004) Oil: $ 36.50 / 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

5. 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

6. 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

7. Page 7 Unocal 3Q 2004 Material Hedge Positions Fixed Price Gas, MMMBTU280$5.66 Oil, MBO17$ 34.60 Collars CeilingFloor Oil, MBO2$28.40$24.00 Daily Volume Fixed Price

8. 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

9. Page 9 Reported First Quarter 2004 2691.00 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 12.04 Unocal 1Q Reported and Adjusted Earnings $ Million$ Per Share Adjusted First Quarter 2004239.89

10. Page 10 First Quarter 2004239.89 Fourth Quarter 2003167.63 Increase 72.26 Factors: Higher worldwide oil/liquids prices 19.07 ($30.64 vs. $28.33) Higher worldwide gas prices39.14 ($4.00 vs. $3.65) Lower E&P expenses 27.10 Higher Earnings from non E&P Oper. 10.04 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

11. 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

12. Page 12 Unocal E&P Canada Results 1Q 2004 vs. 4Q 2003 $ Million Canada - Higher results5 Higher Prices8 Liquids ($ 28.51 vs. 22.94) Gas ($ 5.08 vs, $4.34) Lower Volumes(2) Other(1)

13. 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

14. 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

15. 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)