SPE GCS General Meeting Luncheon March 14, 2002

1. SPE GCS General Meeting Luncheon March 14, 2002

2. 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.

3. Company Overview • Founded in 1991 • A “D & P” company • Development and Production • Offshore solution provider for exploration-oriented majors and independents • Geographic Focus • Over 50 offshore blocks acquired in Gulf of Mexico • Acquired 7 offshore blocks in North Sea

4. Strategy and property overview • Company StrategyAcquire, develop and produce proved reserves WC 101 WC 152

5. Company history ATP was founded in 1991 and completed an initial public offering in February 2001 ATP awarded UKCS Blocks 42/25a and 43/21a by DTI as an Out of Round License ATP acquires the third-party interests from its two partnerships and enters into a new financing arrangement ATP forms a second partnership and commences development activities in the Gulf of Mexico ATP acquires all properties of Statoil (US) on the outer-Continental Shelf of the Gulf of Mexico The Company is incorporated on August 8th ATP opens the U.K. office commencing operations in the Southern Gas Basin of the UK North Sea 2002 1991 1993 1994 1995 1996 1997 1998 1999 2000 2001 ATP forms its first limited partnership to provide funding for operations ATP becomes one of the first independent development companies to utilize horizontal drilling in offshore operations The Company completes its first sub-sea development ATP wins numerous awards for its outstanding technological achievements and growth record The Company completes its initial public offering in February and acquires its first properties in the UK North Sea

6. Strong development track record • Inception (1991) – December 31, 2001 • PUD’s taken to production 28 • PUD’s in development planning 12 • Extensive Subsea Expertise • Subsea Wells Operated 10 • Subsea Development Wells Planned 7 • Industry Leader in Long Reach Subsea Tiebacks • - Ladybug 18 miles 100% of properties under development are operated, allowing control of the timing and amount of capital expenditure

7. SPE Presentation Title Taking Gulf Technology to the North Sea

8. North Sea

9. UK Southern Gas Basin

10. North Sea Southern Gas Basin

11. Garden Banks 409 (Ladybug) WC 101 WC 152 • Ladybug • ATP Operated • Two subsea wells

12. Ladybug Umbilical

13. Subsea Development

14. Garden Banks 409 (Ladybug) WC 101 WC 152 • Ladybug • 1 million barrels produced after 135 days

15. 2001 Benchmarks Production Reserves Reserve Replacement Debt Revenues EBITDA Cash Flow

16. Production Reserves Reserve Replacement Debt Revenues EBITDA Cash Flow ATP Record From 125 Bcfe in 2000 to 235 Bcfe in 2001 527% Reduced 14% Grew by 5+% 64+% of Revenues Over 62% for 6 straight years Grew by 10+% 2001 Benchmarks

17. Operational Expertise of Senior Officers Name Age Background Leland E Tate 54 - President, ARCO North Africa Senior Vice President - Director General, ARCO Joint Ventures Operations - Director of Operations, ARCO British Ltd, North Sea - VP Engineering, ARCO International - Vice President, ARCO Gulf of Mexico Adrian Turner 47 - President, ARCO Middle East Managing Director - Managing Director, ARCO Asia Pacific ATP Oil & Gas (UK) Ltd. - Commercial Vice President, BP Amoco - Commercial Negotiator, ARCO UK and Conoco, North Sea G. Ross Frazer 46 - Operations and Engineering Manager, British-Borneo Exploration, Inc. Vice President - - Chairman, American Petroleum Institute Houston Chapter Advisory Board Engineering - Member, American Petroleum Institute Houston Chapter – Deep Water Operations Steering Committee Robert M. Shivers 44 - Commercial/Development Manager – Deepwater Gulf of Mexico, Texaco Vice President - - Asset and Project Team Manager – UK North Sea, Texaco Projects - Drilling Engineering Manager – Gulf of Mexico/North Sea, Texaco

18. Southern Gas Basin (SGB) ATP Acquisition Blocks

19. Investment Considerations • Six straight years of increases in Production Reserves Revenues EBITDA Cash flow • ATP Upside North Sea Shallow deepwater GOM Outer Continental Shelf

20. E&P Valuation Table Sorted by Enterprise Value to 2002 EBITDA

21. E&P Valuation Table by YTD Stock Price Performance

22. Investment Considerations • Stock price February 22, 2002 $1.68 • Stock price to cash flow 0 .7X • Stock price to proved reserves $0.14 / mcfe

23. Recipient of numerous oil & gas industry and business awards T. Paul BulmahnEntrepreneur of Year 2000Energy & Energy ServicesErnst & Young 2000 Inc./CiscoGrowing with Technology Award Inc. 5003 Consecutive Years 1999-2001Fastest Growing Energy CompanyEach Year Oil & Gas World 1999 Best Field ImprovementGulf of Mexico Financial Times of London2000 Finalist: Best Oil and Gas Company

24. NASDAQ: ATPGATP Oil & Gas Corporation4600 Post Oak Place, Suite 200Houston, TX 77027-9726713-622-3311www.atpog.com