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ATP Oil & Gas Corporation

Denver Presentations

September 16-17, 2002

ATPOil & Gas

Corporation

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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.

ATPOil & Gas

Corporation

Area of Operations

Over 50 blocks in Gulf of Mexico7 blocks in North Sea

ATPOil & Gas

Corporation

4

Company Profile

• Ticker: ATPG

• Production:• 2001 Actual: 25.7

Bcfe• 2002 Guidance: 26.5 Bcfe

• Proven reserves 2001: 235 Bcfe

• 3-year reserve replacement: 374%

• 3-year F&D costs:$0.96/Mcfe

ATPOil & Gas

Corporation

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Company Overview

• Development and production company

• Offshore solution

provider for exploration

oriented majors and

independents

• Unique, repeatable strategy

ATPOil & Gas

Corporation

SMI 189/190

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Our D&P Strategy Works ATPOil & Gas

Corporation

For the Sellers

Eliminates future capital risk

Allows them to recover some sunk

costs

Diverts capital to other core projects

For ATP

Eliminates exploration risk

Reduces acquisition &

development costs

Shortens duration of risked capital

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Company History ATPOil & Gas

Corporation

1995 2002200219971991

ATP incorporated on August 8th

ATP completes its first sub-sea development

ATP acquires all Statoil’s properties

on the Outer-Continental Shelf

ATP is one of the first companies to utilize horizontal drilling offshore

1998

ATP awarded UKCS Blocks by DTI in a rare Out- of-Round license

ATP was founded in 1991 and completed an initial public offering in February 2001

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Recent Focus ATPOil & Gas

Corporation

• Increasing financial flexibility – Reduced debt $28 million– Increased liquidity $22 million

• Exceeding operating goals– Decreased second quarter LOE / Mcfe 17%– Beat first half 2002 production guidance by 17%

• Developing North Sea reserves– Pipeline installed and well drilling at Helvellyn– First production in 2003

• Making money– Discretionary cash flow increased from $4 to $48 million (‘97-’01)– Profitable in second quarter 2002

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2002 Development Activity ATPOil & Gas

Corporation

Gulf of Mexico

South Marsh Island 189 PDNP to PDPProjected start date April 2002

Actual first production March 18, 2002

Eugene Island 71 PUD to PDPInitial production Feb 2002

Increased production June 2002

West Cameron 101 PUD to PDPProjected start date 4th Quarter

13 workovers PDNP to PDP

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Development Activity

Gulf of Mexico ATP is moving 32 Bcfe from non-producing

to proven developed producing properties (PDP) for less than $20 million, while increasing total PDP reserves 15% to 42 Bcf.

ATPOil & Gas

Corporation

Area of Operations ATPOil & Gas

Corporation

WC 101

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West Cameron 101 ATPOil & Gas

Corporation

Water Depth: 43’Working Interest: 100%Net Revenue Interest: 73.33%Platform/Wells: One well caisson.First Production: 4th Q 2002 (proposed)Producing Sands: Miocene Marg A 53 thru 55 Sands at

13,000’ TVD

Current Status:

Caisson waiting on completion

Location:Offset Mobil L-2 well -555 MBO2 BCFGSuperior C-3, C-7 wells also prod. 53 and 55 sands.

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West Cameron 101 #2 Log ATPOil & Gas

Corporation

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Future Development (2003 – 2005)

Future developments

100% of properties ATP operated

ATPOil & Gas

Corporation

ATP Oil & Gas Corporation

North Sea Developments

ATPOil & Gas

Corporation

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Southern Gas Basin of North Sea ATPOil & Gas

Corporation

The Tors

Helvellyn

Venture

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HelvellynATPOil & Gas

Corporation

Water Depth: 90’Working Interest: 100%Net Revenue Interest: 100%Platform/Wells: SubseaFirst Production:Projected 2003

Producing Sands: Rotliegend/Carboniferous

First well drilled: 1985First well tested: 47/10-1 well tested at 29.4

MMcfepd

ATP proposed well: 2,000 foot horizontal section through both

producing sands

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Helvellyn Development ATPOil & Gas

Corporation

Development 2002Projected production

2003

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Helvellyn Development August 2002 Pipeline Lay

ATPOil & Gas

Corporation

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Helvellyn DevelopmentWellhead Protection Structure

ATPOil & Gas

Corporation

Well Spudded September 8, 2002

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Venture ATPOil & Gas

Corporation

Development 2003Projected production

2004

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The Tors ATPOil & Gas

Corporation

10km

Development 2004Projected production

2005

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Financial Overview

ATPOil & Gas

Corporation

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Debt Reduction Program ATPOil & Gas

Corporation

$116

$100

$90 $88

$0

$20

$40

$60

$80

$100

$120

$140

2000 2001 2Q02 8/31/2002

($ in millions)

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First Half 2002 Capital Liquidity Improvement

ATPOil & Gas

Corporation

Working Capital Increased $12.2 million

+Bank and Subordinated Debt Decreased $10.0 million

=Overall Capital LiquidityImprovement $22.2 million

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2002 Operating Performance

ATPOil & Gas

Corporation

($6)

$3

$11

$18

$26

$20

($10)

($5)

$0

$5

$10

$15

$20

$25

$30

1Q02 2Q02

Net Income

Discretionary Cash Flow

Revenue

($ in millions)

Gross Margin

87% 2Q02

Note: Revenue reflect the effects of settled hedging activity

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Financial Strength ATPOil & Gas

Corporation

• Long-term debt / proven reserves(1)$0.38 / Mcfe

• EBITDA / Interest(2) 7.7X

• Bank credit facility(1) $62

million

• 1H02 Discretionary cash flow $29

million

• Capex(3)

• 1st half 2002 $12 million

• 2002 E $20

million

(1) At June 30, 2002

(2) Based on 2Q02 results

(3) Gulf of Mexico only

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Why Should ATP Be In Your Portfolio?

ATPOil & Gas

Corporation

• Comparable to larger Gulf of Mexico operators

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Our Peers ATPOil & Gas

Corporation

Ticker Company % GOM % Gas % GOM % Gas

ATPG ATP Oil & Gas Corp. 66% 83% 100% 71%

EPL Energy Partners Ltd. 100% 29% 100% 51%

NFX Newfield Exploration Co. 58% 77% 66% 80%

PQUE Petroquest Energy, Inc. 52% 55% 52% 60%

REM Remington Oil & Gas Corp. 82% 57% 80% 64%

SGY Stone Energy Corp. 91% 57% 92% 65%

Median 74% 57% 86% 64%

2Q02 ProductionProven Reserves

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Why Should ATP Be In Your Portfolio?

ATPOil & Gas

Corporation

• Comparable to larger Gulf of Mexico operators

• Attractive valuation

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Attractive ValuationP/CFPS significantly below peers

ATPOil & Gas

Corporation

2002E P/CFPS 1.4X vs. Median 3.7X

0.0x

1.0x

2.0x

3.0x

4.0x

5.0x

6.0x

ATPG EPL SGY Median NFX REM PQUE

Note: FC-CFPS $2.28; Price 09/12/02 $3.25

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Attractive ValuationEV trades at a discount to NAV

ATPOil & Gas

Corporation

Enterprise Value / Proven Reserves ($/Mcfe)

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

ATPG EPL SGY Median REM NFX PQUE

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Why Should ATP Be In Your Portfolio?

ATPOil & Gas

Corporation

• Comparable to larger Gulf of Mexico operators

• Attractive valuation

• Efficient Gulf of Mexico operator

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Efficient Gulf of Mexico Operator

Lowest production costs in the group

ATPOil & Gas

Corporation

Production Costs(1) / Mcfe

$0.00

$0.20

$0.40

$0.60

$0.80

$1.00

$1.20

ATPG REM SGY Median NFX PQUE EPL

(1) 2Q02 LOE, production taxes, and transportation / 2Q02 production

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Why Should ATP Be In Your Portfolio?

ATPOil & Gas

Corporation

• Comparable to larger Gulf of Mexico operators

• Attractive valuation

• Efficient Gulf of Mexico operator

• Rate of return focused

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Rate of Return Focused3-year F&D costs under $1/Mcf

ATPOil & Gas

Corporation

($/Mcfe) = (Costs - divestitures - cap int. - cap g&a)

delta proven reserves + prod.

3-Year F&D Costs 1999-2001

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

ATPG EPL REM Median PQUE NFX SGY

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Rate of Return FocusedCapital Efficiency

ATPOil & Gas

Corporation

Dollars Invested vs. EBITDA Returned(1)

0%

50%

100%

150%

200%

250%

NFX SGY EPL Median PQUE ATPG REM

(1) 2Q:02 EBITDA per unit of production divided by 3 yr. ('99-'01) F&D costs.

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Why Should ATP Be In Your Portfolio?

ATPOil & Gas

Corporation

• Comparable to larger Gulf of Mexico operators

• Attractive valuation

• Efficient Gulf of Mexico operator

• Rate of return focused

• History of producing results

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History of Producing Results6 years of cash flow and revenue

growth

ATPOil & Gas

Corporation

Discretionary Cash Flow

2

49+4843

17

74

Revenue

90+

3

8884

43

208

($ in millions)

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ATPOil & Gas

Corporation

261+235

126104

504739

Production (BCFE) Proven Reserves (BCFE)

2Q02 Production 71% natural gas

26.5+

1 3

10

17

24 26

History of Producing Results6 years of production and reserve

growthOILGAS

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ATP Oil & Gas Corporation ATPOil & Gas

Corporation

NASDAQ: ATPG

ATP Oil & Gas Corporation4600 Post Oak Place,

Suite 200Houston, TX 77027-9726

713-622-3311

ATP Oil & Gas (UK) LimitedVictoria House, London Square, Cross

LanesGuildford, Surrey GU1 1UJ

United Kingdom44 (0) 1483 307200

www.atpog.com