1. ATP Oil & Gas Corporation Commercializing PUD Reserves May 16, 2002 T. Paul Bulmahn Chairman & President ATP Oil & Gas Corporation

2. ATP Oil & Gas Corporation What are PUD Reserves? Proven Undeveloped Reserves (PUDs) Oil and gas reserves: 1.that have been proven with geological and engineering data, 2.that can economically be produced using existing pricing and operating conditions, and 3.that require significant capital to move the reserves to a producing state. ATP Oil & Gas Corporation

3. ATP Oil & Gas Corporation Proved Undeveloped Players ATP Oil & Gas Corporation Gulf of MexicoUK North Sea Governing bodyMMSDTI Holders of PUD projects Majors & Independents Primarily Majors Owners of infrastructure Pipeline companies Majors Developers of projects Primarily Independents Majors & Independents Financing sourcesBanks, mezzanine lenders

4. ATP Oil & Gas Corporation Current Issues Owners and Developers (Majors and Independents): Small fallow projects will probably not be developed by Majors Technology is available to the independents to develop fallow fields Independents need reasonable tariffs for pipelines and processing production from smaller fields Independents need funding to develop properties ATP Oil & Gas Corporation

5. ATP Oil & Gas Corporation PUD Reserves Low risk, because “proved” ATP has developed and placed on production 29 out of 30 offshore PUDs ATP Oil & Gas Corporation

6. ATP Oil & Gas Corporation Hurdles to Financing PUDs Proven yet undeveloped reserves Ability of developer to bring the PUD to production Ability of developer to produce economically Commodity pricing fluctuations ATP Oil & Gas Corporation

7. ATP Oil & Gas Corporation Current Issues Banks and Financing Entities: Financing opportunities are estimated in the billions of pounds Creation of a new business segment /area of marketing for banks and financing sources What will allow banks to fund independents when the primary collateral is PUDs? ATP Oil & Gas Corporation

8. ATP Oil & Gas Corporation Areas of Consideration in Advancing Funds Criteria for Developers: History of converting PUDs to PDPs Base of proved reserves Technical expertise Management of risk Resilience to industry cycles Operational safety record Concentration ATP Oil & Gas Corporation

9. ATP Oil & Gas Corporation History of Converting PUDs to PDPs Strong Development Track Record Inception (1991) – March 31, 2002 PUDs taken to production 29 PUDs in development planning12 Gulf of Mexico 7 North Sea 5 100% of properties under development are operated, allowing control of the timing and amount of capital expenditure Extensive Subsea Expertise Subsea Wells Operated 10 Subsea Development Wells Planned 7 Industry Leader in Long Reach Subsea Tiebacks - Most recent development is an 18 mile tieback to a platform in 900 feet of water ATP Oil & Gas Corporation

10. ATP Oil & Gas Corporation Proved Reserves December 31, 2001 ATP Oil & Gas Corporation

11. ATP Oil & Gas Corporation Proved Reserves ATP Oil & Gas Corporation Gulf of MexicoNorth Sea December 31, 2001 Proved Developed Proved Undeveloped

12. ATP Oil & Gas Corporation North Sea Southern Gas Basin ATP Oil & Gas Corporation Helvellyn Out of Round Awarded February, 2002

13. ATP Oil & Gas Corporation Reserve Replacement Average Reserve Replacement: 1997-2000 259% 2001527% ATP Oil & Gas Corporation

14. ATP Oil & Gas Corporation Staff Expertise ATP Oil & Gas Corporation Technical Staff – Average Offshore Industry Tenure 22 Years Employee Academic Backgrounds One College Degree Additional Graduate Degrees and Professional Certifications 85% 60%

15. ATP Oil & Gas Corporation Quality of Outside Reserve Engineer ATP Oil & Gas Corporation Gulf of Mexico ATP Oil & Gas employs Ryder Scott North Sea ATP Oil & Gas (UK) Ltd. employs Troy Ikoda

16. ATP Oil & Gas Corporation Estimation of Reserves ATP Oil & Gas Corporation Deterministic Method – SEC Article 210.4-10(a) of Regulations S-X (17 CFR 210) of United States Securities and Exchange Commission Probabilistic Method - SPE Joint Reserve Definitions of the Society of Petroleum Engineers and the World Petroleum Congress

17. ATP Oil & Gas Corporation Management of Risk ATP Oil & Gas Corporation Business risk Niche focus since 1991 No exploration PUD properties Incorporation of industry technology Operational risk ATP operates all 12 undeveloped projects ATP operates 22 of 28 producing properties in the Gulf of Mexico

18. ATP Oil & Gas Corporation Management of Risk - Commodity Price Fluctuations ATP Oil & Gas Corporation ATP Philosophy – Hedge to protect the downside and to provide assured economic returns Percentage of oil & gas production hedged: 200259% 200339%

19. ATP Oil & Gas Corporation Resilience to Industry Cycles -- Historical Operating Performance 62% 65% 62% 72% 68% EBITDAREVENU ES ATP Oil & Gas Corporation Consistent EBITDA to Revenue Ratio

20. ATP Oil & Gas Corporation Operational Safety Record ATP Oil & Gas Corporation ATP was nominated for the 2002 National Safety Award of Excellence by the MMS as one of the 5 finalists of 42 companies that currently operate in the Gulf of Mexico

21. ATP Oil & Gas Corporation Concentration ATP Oil & Gas Corporation Lending attitudes need to recognize opportunity

22. ATP Oil & Gas Corporation ATP Approach ATP Oil & Gas Corporation Focused strategy on PUDs Every project is vigorously analyzed by our staff for development, operations and economics

23. ATP Oil & Gas Corporation ATP Approach ATP Oil & Gas Corporation Six straight years of growth in: -Reserves -Production -Revenue -EBITDA -Cash Flow

24. ATP Oil & Gas Corporation Requirements for Success DTI continued encouragement of Major and Independents to work together to: Divest fallow PUD properties Provide less costly access to infrastructure of pipelines and platforms Qualified Independents bringing innovation for low cost PUD development ATP Oil & Gas Corporation

25. ATP Oil & Gas Corporation Requirements for Success Sufficient capital for development of PUDs Change in the attitude of established lenders New lenders with new products ATP Oil & Gas Corporation

26. ATP Oil & Gas Corporation Forward-looking Statement This presentation contains projections and other forward looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These projections and statements reflect the Company’s current view with respect to future events and financial performance. No assurances can be given, however, that these events will occur or that these projections will be achieved, and actual results could differ materially from those projected as result of certain factors. A discussion of these factors is included in the Company documents filed with the Securities and Exchange Commission. This presentation does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy or an attempt to influence any voting of securities, by any person. ATP Oil & Gas Corporation

27. ATP Oil & Gas Corporation NASDAQ: ATPG ATP Oil & Gas Corporation 4600 Post Oak Place, Suite 200 Houston, TX 77027-9726 713-622-3311 www.atpog.com ATP Oil & Gas Corporation