Exhibit 10.1

EXECUTION COPY

1,250,000

ATP Oil & Gas Corporation

8.00%Convertible Perpetual Preferred Stock

PURCHASE AGREEMENT

September 23, 2009

CREDIT SUISSE SECURITIES (USA) LLC

J.P. MORGAN SECURITIES INC.

As Representatives of the several Purchasers

c/o Credit Suisse Securities (USA) LLC (“Credit Suisse”)

Eleven Madison Avenue,

New York, N.Y. 10010-3629

Dear Sirs:

1. Introductory. ATP Oil & Gas Corporation, a Texas corporation (the “Company”),
agrees with the several initial purchasers named in Schedule A hereto (the
“Purchasers”), for whom you are acting as the representatives (the
“Representatives”), subject to the terms and conditions stated herein, to issue
and sell to the several Purchasers 1,250,000 shares of its 8.00% Convertible
Perpetual Preferred Stock (the “Firm Securities”) and also proposes to grant to
the Purchasers an option, exercisable from time to time by the Representatives,
to purchase an aggregate of up to an additional 350,000 shares (“Optional
Securities”) of its 8.00% Convertible Perpetual Preferred Stock. The Firm
Securities and the Optional Securities which the Purchasers may elect to
purchase pursuant to Section 3 hereof are herein collectively called the
“Offered Securities”.

The Offered Securities will be convertible, subject to certain conditions set
forth in the Statement of Resolutions establishing the Offered Securities, at
the option of the holder for shares of common stock, par value $0.001 per share,
of the Company (the “Common Stock”), in accordance with the terms of the Offered
Securities.

The Company hereby agrees with the several Purchasers as follows:

1. Representations and Warranties of the Company. The Company represents and
warrants to, and agrees with, the several Purchasers that:

(a) Offering Circulars; Certain Defined Terms. The Company has prepared or will
prepare a Preliminary Offering Circular and a Final Offering Circular.

For purposes of this Agreement:

“Applicable Time” means 8:00 p.m. (New York City time) on the date of this
Agreement.

“Closing Date” has the meaning set forth in Section 3 hereof.

“Commission” means the Securities and Exchange Commission.

“Exchange Act” means the United States Securities Exchange Act of 1934.

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“Final Offering Circular” means the final offering circular (including all
documents incorporated by reference therein) relating to the Offered Securities
to be offered by the Purchasers that discloses the offering price and other
final terms of the Offered Securities and is dated as of the date of this
Agreement (even if finalized and issued subsequent to the date of this
Agreement).

“Free Writing Communication” means a written communication (as such term is
defined in Rule 405) that constitutes an offer to sell or a solicitation of an
offer to buy the Offered Securities and is made by means other than the
Preliminary Offering Circular or the Final Offering Circular.

“General Disclosure Package” means the Preliminary Offering Circular together
with any Issuer Free Writing Communication existing at the Applicable Time and
the information in which is intended for general distribution to prospective
investors, as evidenced by its being specified in Schedule B hereto.

“Issuer Free Writing Communication” means a Free Writing Communication prepared
by or on behalf of the Company, used or referred to by the Company or containing
a description of the final terms of the Offered Securities or of their offering,
in the form retained in the Company’s records.

“Preliminary Offering Circular” means the preliminary offering circular
(including all documents incorporated by reference therein), dated September 22,
2009, relating to the Offered Securities to be offered by the Purchasers.

“Rules and Regulations” means the rules and regulations of the Commission.

“Securities Act” means the United States Securities Act of 1933.

“Securities Laws” means, collectively, the Sarbanes-Oxley Act of 2002
(“Sarbanes-Oxley”), the Act, the Exchange Act, the Rules and Regulations, the
auditing principles, rules, standards and practices applicable to auditors of
“issuers” (as defined in Sarbanes-Oxley) promulgated or approved by the Public
Company Accounting Oversight Board and, as applicable, the rules of the New York
Stock Exchange and the NASDAQ Stock Market (“Exchange Rules”).

“Supplemental Marketing Material” means any Issuer Free Writing Communication
other than any Issuer Free Writing Communication specified in Schedule B hereto.
Supplemental Marketing Materials include, but are not limited to, any Issuer
Free Writing Communication listed on Schedule C hereto.

“Underlying Shares” means shares of Common Stock into which the Offered
Securities are convertible or shares of Common Stock that may be issued as
dividends on the Offered Securities or may otherwise be issued in respect of the
Offered Securities.

Unless otherwise specified, a reference to a “rule” is to the indicated rule
under the Securities Act.

(b) Disclosure. As of the date of this Agreement, the Final Offering Circular
does not, and as of each Closing Date, the Final Offering Circular will not
include any untrue statement of a material fact or omit to state any material
fact necessary in order to make the statements therein, in the light of the
circumstances under which they were made, not misleading. At the Applicable Time
neither (i) the General Disclosure Package nor (ii) any individual Supplemental
Marketing Material, when considered together with the General Disclosure
Package, included any untrue statement of a material fact or omitted to state
any material fact necessary in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading. The
preceding two sentences do not apply to statements in or omissions from the
Preliminary or Final Offering Circular, the General Disclosure Package or any
Supplemental Marketing Material based upon written information furnished to the
Company by any Purchaser through the Representatives specifically for use
therein, it being understood and agreed that the only such information is that
described as such in Section 8(b) hereof. Except as disclosed in the General
Disclosure Package, on the date of this Agreement, the Company’s Annual Report
on Form 10-K

 

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most recently filed with the Commission and all subsequent reports
(collectively, the “Exchange Act Reports”) which have been filed by the Company
with the Commission or sent to shareholders pursuant to the Exchange Act do not
include any untrue statement of a material fact or omit to state any material
fact necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading. Such documents, when they were filed
with the Commission, conformed in all material respects to the requirements of
the Exchange Act and the Rules and Regulations.

(c) Good Standing of the Company. The Company has been duly incorporated and is
existing and in good standing under the laws of the State of Texas, with power
and authority (corporate and other) to own its properties and conduct its
business as described in the General Disclosure Package and the Final Offering
Circular; and the Company is duly qualified to do business as a foreign
corporation in good standing in all other jurisdictions in which its ownership
or lease of property or the conduct of its business requires such qualification.

(d) Subsidiaries. Each subsidiary of the Company has been duly incorporated and
is existing and in good standing under the laws of the jurisdiction of its
incorporation, with power and authority (corporate and other) to own its
properties and conduct its business as described in the General Disclosure
Package and the Final Offering Circular; and each subsidiary of the Company is
duly qualified to do business as a foreign corporation in good standing in all
other jurisdictions in which its ownership or lease of property or the conduct
of its business requires such qualification, except where the failure to so
qualify would not have, individually or in the aggregate, a material adverse
effect on the business, financial position, or results of operations of the
Company and its subsidiaries taken as a whole or on the performance by the
Company of its obligations under this Agreement (“Material Adverse Effect”); all
of the issued and outstanding capital stock of each subsidiary of the Company
has been duly authorized and validly issued and is fully paid and nonassessable;
and, except as disclosed in the General Disclosure Package and the Final
Offering Circular, the capital stock of each subsidiary owned by the Company,
directly or through subsidiaries, is owned free from liens, encumbrances and
defects.

(e) Offered Securities. The Offered Securities and all other outstanding shares
of capital stock of the Company have been duly authorized; and when the Offered
Securities are delivered and paid for pursuant to this Agreement on each Closing
Date, such Offered Securities will have been validly issued, fully paid and
nonassessable, will conform to the information in the General Disclosure Package
and will conform to the description of such Offered Securities contained in the
Final Offering Circular; and the shareholders of the Company have no preemptive
rights with respect to the Offered Securities; none of the outstanding shares of
capital stock of the Company are or will have been issued in violation of any
preemptive or similar rights of any security holder; and the authorized equity
capitalization of the Company is as set forth in the General Disclosure Package
and the Final Offering Circular.

(f) Underlying Shares. When the Offered Securities are delivered and paid for
pursuant to this Agreement on each Closing Date, such Offered Securities will be
convertible into the Underlying Shares of the Company in accordance with their
terms; the Underlying Shares initially issuable upon conversion of such Offered
Securities have been duly authorized and reserved for issuance upon such
conversion and will conform to the information in the General Disclosure Package
and will conform to the description of such Underlying Shares contained in the
Final Offering Circular; all outstanding shares of capital stock of the Company
are, and when issued upon conversion of the Offered Securities the Underlying
Shares will be, validly issued, fully paid and nonassessable; and the
shareholders of the Company have no preemptive rights with respect to the
issuance of the Underlying Shares upon the conversion of the Offered Securities.

(g) No Finder’s Fee. Neither the Company nor any of its subsidiaries is a party
to any contract, agreement or understanding with any person (other than this
Agreement) that would give rise to a valid claim against the Company or any of
its subsidiaries or any Purchaser for a brokerage commission, finder’s fee or
like payment in connection with the offering and sale of the Offered Securities.

 

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(h) Absence of Further Requirements. No consent, approval, authorization, order,
license, registration or qualification of or with any court or arbitrator or
governmental or regulatory authority is required for the execution, delivery and
performance by the Company of this Agreement, the issuance and sale of the
Offered Securities and the Underlying Shares and the consummation of the
transactions contemplated by this Agreement and described in the General
Disclosure Package and Final Offering Circular.

(i) Stock Options. With respect to the stock options (the “Stock Options”)
granted pursuant to the stock-based compensation plans of the Company and its
subsidiaries (the “Company Stock Plans”), (A) each Stock Option intended to
qualify as an “incentive stock option” under Section 422 of the Code so
qualifies, (B) each grant of a Stock Option was duly authorized no later than
the date on which the grant of such Stock Option was by its terms to be
effective (the “Grant Date”) by all necessary corporate action, including, as
applicable, approval by the board of directors of the Company (or a duly
constituted and authorized committee thereof) and any required shareholder
approval by the necessary number of votes or written consents, and the award
agreement governing such grant (if any) was duly executed and delivered by each
party thereto, (C) each such grant was made in accordance with the terms of the
Company Stock Plans, the Exchange Act and all other applicable laws and
regulatory rules or requirements, including the rules of the Nasdaq Global
Select Market and any other exchange on which Company securities are traded, and
(D) each such grant was properly accounted for in accordance with generally
accepted accounting principles in the financial statements (including the
related notes) of the Company and disclosed in the Company’s filings with the
Commission in accordance with the Exchange Act and all other applicable laws.
The Company has not knowingly granted, and there is no and has been no policy or
practice of the Company of granting, Stock Options prior to, or otherwise
coordinating the grant of Stock Options with, the release or other public
announcement of material information regarding the Company or its subsidiaries
or their results of operations or prospects.

(j) Title to Real and Personal Property. Except as disclosed in the General
Disclosure Package and the Final Offering Circular or such as in the aggregate
does not now cause nor will it in the future cause a Material Adverse Effect,
the Company and its subsidiaries have title to their properties as follows:
(A) with respect to their wells (including leasehold interests and appurtenant
personal property) and their non-producing oil and gas properties (including
undeveloped locations on leases held by production and those leases not held by
production), such title is valid and defensible and free and clear of all liens,
security interests, pledges, charges, encumbrances, mortgages and restrictions,
(B) with respect to their non-producing properties in exploration prospects,
such title was investigated in accordance with customary industry procedures
prior to the Company or its subsidiaries’ acquisition thereof; (C) with respect
to their real property other than oil and gas interests, such title is good and
marketable free and clear of all liens, security interests, pledges, charges,
encumbrances, mortgages and restrictions; and (D) with respect to their personal
property other than that appurtenant to its oil and gas interests, such title is
free and clear of all liens, security interests, pledges, charges, encumbrances,
mortgages and restrictions. No real property owned, leased, licensed, or used by
the Company or its subsidiaries lies in an area which is, or to the knowledge of
the Company will be, subject to restrictions which would prohibit, and no
statements of facts relating to the actions or inaction of another person or
entity or his or its ownership, leasing, licensing, or use of any real or
personal property exists or will exist which would prevent, the continued
effective ownership, leasing, licensing, exploration, development or production
or use of such real property in the business of the Company as presently
conducted or as the General Disclosure Package or the Final Offering Circular
indicates they contemplate conducting, except as disclosed in the General
Disclosure Package and the Final Offering Circular or such as in the aggregate
do not now cause and will not in the future reasonably be expected to cause a
Material Adverse Effect.

 

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(k) Title to Intellectual Property. The Company and its subsidiaries own or
possess, or can acquire on reasonable terms, adequate patents, patent rights,
licenses, inventions, copyrights, know-how, confidential information,
trademarks, service marks, trade names or other intellectual property
(collectively, “Intellectual Property”) necessary to carry on the business now
operated by them, except where the failure to own or possess, or have the
ability to acquire on reasonable terms such Intellectual Property, would not
reasonably be expected to cause, individually or in the aggregate, a Material
Adverse Effect. Neither the Company nor any subsidiary has received any notice
of any infringement of or conflict with asserted rights of others with respect
to any Intellectual Property that if determined adversely to the Company would
result in, individually or in the aggregate, a Material Adverse Effect.

(l) Absence of Defaults and Conflicts Resulting from Transaction. The execution,
delivery and performance by the Company of each of this Agreement, the issuance
and sale of the Offered Securities and the Underlying Shares and the
consummation of the transactions contemplated by this Agreement and described in
the General Disclosure Package and Final Offering Circular will not (i) conflict
with or result in a breach or violation of any of the terms or provisions of, or
constitute a default under, or result in the creation or imposition of any lien,
charge or encumbrance upon any property or assets of the Company or any of its
subsidiaries pursuant to, any indenture, mortgage, deed of trust, loan agreement
or other agreement or instrument to which the Company or any of its subsidiaries
is a party or by which the Company or any of its subsidiaries is bound or to
which any of the property or assets of the Company or any of its subsidiaries is
subject, (ii) result in any violation of the provisions of the charter or
by-laws or similar organizational documents of the Company or any of its
subsidiaries or (iii) result in the violation of any law or statute or any
judgment, order, rule or regulation of any court or arbitrator or governmental
or regulatory authority, except, in the case of clauses (i) and (iii) above, for
any such conflict, breach, violation or default that would not, individually or
in the aggregate, have a Material Adverse Effect.

(m) Absence of Existing Defaults and Conflicts. Neither the Company nor any of
its subsidiaries is (i) in violation of its charter or by-laws or similar
organizational documents; (ii) in default, and no event has occurred that, with
notice or lapse of time or both, would constitute such a default, in the due
performance or observance of any term, covenant or condition contained in any
indenture, mortgage, deed of trust, loan agreement or other agreement or
instrument to which the Company or any of its subsidiaries is a party or by
which the Company or any of its subsidiaries is bound or to which any of the
property or assets of the Company or any of its subsidiaries is subject; or
(iii) in violation of any law or statute or any judgment, order, rule or
regulation of any court or arbitrator or governmental or regulatory authority,
except, in the case of clauses (ii) and (iii) above, for any such default or
violation that would not, individually or in the aggregate, have a Material
Adverse Effect.

(n) Authorization of Agreement. The Company has full right, power and authority
to execute and deliver this Agreement and to perform its obligations hereunder;
and all action required to be taken for the due and proper authorization,
execution and delivery by it of this Agreement and the consummation by it of the
transactions contemplated hereby has been duly and validly taken. This Agreement
has been duly authorized, executed and delivered by the Company.

(o) Possession of Licenses and Permits. The Company and its subsidiaries possess
all licenses, certificates, permits and other authorizations issued by the
appropriate Federal, state, local or foreign governmental or regulatory
authorities that are necessary for the ownership or lease of their respective
properties or the conduct of their respective businesses as described in the
General Disclosure Package and the Final Offering Circular, except where the
failure to so possess would not have, individually or in the aggregate, a
Material Adverse Effect; except as described in the General Disclosure Package
and the Final Offering Circular, the Company and its subsidiaries are in
compliance with the terms and conditions of all such licenses, certificates,
permits and authorizations, except where the failure to so comply would not
have, individually or in the aggregate, a Material Adverse Effect; and except as
described in the General Disclosure Package

 

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and the Final Offering Circular, neither the Company nor any of its subsidiaries
has received notice of any revocation or modification of any such license,
certificate, permit or authorization which, individually or in the aggregate, if
subject to an unfavorable decision, ruling or finding would result in a Material
Adverse Effect.

(p) Absence of Labor Dispute. No labor disturbance by or dispute with employees
of the Company or any of its subsidiaries exists or, to the knowledge of the
Company, is imminent, and the Company is not aware of any existing or imminent
labor disturbance by, or dispute with, the employees of any of its or its
subsidiaries’ principal suppliers, contractors or customers, except as would not
have a Material Adverse Effect.

(q) Environmental Laws. (A) The Company and its subsidiaries (1) are in
compliance with any and all applicable Federal, state, local and foreign laws,
rules, regulations, requirements, decisions, judgments, decrees, and orders
relating to pollution or the protection of the environment, natural resources or
human health or safety, including those relating to the generation, storage,
treatment, use, handling, transportation, Release or threat of Release of
Hazardous Materials (collectively, “Environmental Laws”), (2) have received and
are in compliance with all permits, licenses, certificates or other
authorizations or approvals required of them under applicable Environmental Laws
to conduct their respective businesses, (3) have not received notice of any
actual or potential liability under or relating to, or actual or potential
violation of, any Environmental Laws, including for the investigation or
remediation of any Release or threat of Release of Hazardous Materials, and have
no knowledge of any event or condition that would reasonably be expected to
result in any such notice, (4) are not conducting or paying for, in whole or in
part, any investigation, remediation or other corrective action pursuant to any
Environmental Law at any location, and (5) are not a party to any order, decree
or agreement that imposes any obligation or liability under any Environmental
Law, except for any such matter as would not reasonably be expected to have,
individually or in the aggregate, a Material Adverse Effect, and (B) there are
no costs or liabilities associated with Environmental Laws of or relating to the
Company or its subsidiaries, except for any such matter as would not reasonably
be expected to have, individually or in the aggregate, a Material Adverse
Effect; and (C) except as described in the General Disclosure Package and the
Final Offering Circular, (1) there are no proceedings that are pending, or that
are known to be contemplated, against the Company or any of its subsidiaries
under any Environmental Laws in which a governmental entity is also a party,
other than such proceedings regarding which it is reasonably believed no
monetary sanctions of $100,000 or more will be imposed, and (2) the Company and
its subsidiaries are not aware of any facts or issues regarding compliance with
Environmental Laws, or liabilities or other obligations under Environmental
Laws, including the Release or threat of Release of Hazardous Materials, that
could reasonably be expected to have a material effect on the capital
expenditures, earnings or competitive position of the Company and its
subsidiaries.

(r) Hazardous Materials. There has been no storage, generation, transportation,
use, handling, treatment, Release or threat of Release of Hazardous Materials
by, relating to or caused by the Company or any of its subsidiaries (or, to the
knowledge of the Company and its subsidiaries, any other entity (including any
predecessor) for whose acts or omissions the Company or any of its subsidiaries
is or could reasonably be expected to be liable) at, on, under or from any
property or facility now or previously owned, operated or leased by the Company
or any of its subsidiaries, or at, on, under or from any other property or
facility, in violation of any Environmental Laws or in a manner or amount or to
a location that could reasonably be expected to result in any liability of the
Company or any of its subsidiaries under any Environmental Law, except for any
violation or liability which would not reasonably be expected to have,
individually or in the aggregate, a Material Adverse Effect. “Hazardous
Materials” means any material, chemical, substance, waste, pollutant,
contaminant, compound, mixture, or constituent thereof, in any form or amount,
including petroleum (including crude oil or any fraction thereof) and petroleum
products, natural gas, natural gas liquids, asbestos and asbestos containing
materials, naturally occurring radioactive materials, brine, and drilling mud,
regulated or which can give rise to liability under any Environmental Law.
“Release” means any spilling, leaking, seepage,

 

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pumping, pouring, emitting, emptying, discharging, injecting, escaping,
leaching, dumping, disposing, depositing, dispersing, or migrating in, into or
through the environment, or in, into, from or through any building or structure

(s) Absence of Manipulation. Neither the Company nor any of its affiliates has,
either alone or with one or more other persons, bid for or purchased for any
account in which it or any of its affiliates had a beneficial interest any
Offered Securities or attempted to induce any person to purchase any Offered
Securities.

(t) Statistical and Market-Related Data. Any third-party statistical and
market-related data included in a Preliminary Offering Circular, a Final
Offering Circular, or any Issuer Free Writing Communication are based on or
derived from sources that the Company believes to be reliable and accurate.

(u) Disclosure Controls. The Company and its subsidiaries maintain an effective
system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of
the Exchange Act) that complies with the requirements of the Exchange Act and
that has been designed to ensure that information required to be disclosed by
the Company in reports that it files or submits under the Exchange Act is
recorded, processed, summarized and reported within the time periods specified
in the Commission’s rules and forms, including controls and procedures designed
to ensure that such information is accumulated and communicated to the Company’s
management as appropriate to allow timely decisions regarding required
disclosure. The Company and its subsidiaries have carried out evaluations of the
effectiveness of their disclosure controls and procedures as required by Rule
13a-15 of the Exchange Act.

(v) Accounting Controls. The Company and its subsidiaries maintain systems of
“internal control over financial reporting” (as defined in Rule 13a-15(f) of the
Exchange Act) that comply with the requirements of the Exchange Act and have
been designed by, or under the supervision of, their respective principal
executive and principal financial officers, or persons performing similar
functions, to provide reasonable assurance regarding the reliability of
financial reporting and the preparation of financial statements for external
purposes in accordance with generally accepted accounting principles, including,
but not limited to, internal accounting controls sufficient to provide
reasonable assurance that (A) transactions are executed in accordance with
management’s general or specific authorizations; (B) transactions are recorded
as necessary to permit preparation of financial statements in conformity with
generally accepted accounting principles and to maintain asset accountability;
(C) access to assets is permitted only in accordance with management’s general
or specific authorization; and (D) the recorded accountability for assets is
compared with the existing assets at reasonable intervals and appropriate action
is taken with respect to any differences. Except as disclosed in the General
Disclosure Package and the Final Offering Circular, the Company is not aware of
(i) any significant deficiencies or material weaknesses in the design or
operation of internal controls or (ii) any fraud, whether or not material, that
involves management or other employees who have a significant role in the
Company’s internal controls over financial reporting which are likely to
adversely affect the Company’s ability to record, process, summarize and report
financial information. The Company’s auditors and the Audit Committee of the
Board of Directors of the Company have been advised of: (1) all significant
deficiencies and material weaknesses in the design or operation of internal
controls over financial reporting which have adversely affected or are
reasonably likely to adversely affect the Company’s ability to record, process,
summarize and report financial information; and (2) any fraud, whether or not
material, that involves management or other employees who have a significant
role in the Company’s internal controls over financial reporting.

(w) Absence of Accounting Issues. A member of the Audit Committee has confirmed
to the Chief Executive Officer, Chief Financial Officer or General Counsel that,
except as set forth in the General Disclosure Package and the Final Offering
Circular, the Audit Committee is not reviewing or investigating, and neither the
Company’s independent auditors nor its internal

 

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auditors have recommended that the Audit Committee review or investigate,
(A) adding to, deleting, changing the application of, or changing the Company’s
disclosure with respect to, any of the Company’s material accounting policies;
(B) any matter which could result in a restatement of the Company’s financial
statements for any annual or interim period during the current or prior three
fiscal years; or (C) any Internal Control Event.

(x) Litigation. Except as disclosed in the General Disclosure Package and the
Final Offering Circular, there are no legal, governmental or regulatory
investigations, actions, suits or proceedings pending to which the Company or
any of its subsidiaries is or may be a party or to which any property of the
Company or any of its subsidiaries is or may be the subject that, individually
or in the aggregate, if determined adversely to the Company or any of its
subsidiaries, would reasonably be expected to have a Material Adverse Effect; no
such investigations, actions, suits or proceedings are threatened by any
governmental or regulatory authority.

(y) Taxes. The Company and its subsidiaries have on a timely basis paid all
Federal, state, local and foreign taxes and filed all tax returns required to be
paid or filed through the date hereof (except in any case in which the failure
to so file has not had and would not reasonably be expected to result in a
Material Adverse Effect); and except as otherwise disclosed in the General
Disclosure Package and the Final Offering Circular, there is no tax deficiency
that has been, or could reasonably be expected to be, asserted against the
Company or any of its subsidiaries or any of their respective properties or
assets, except for any tax deficiency that is currently being contested in good
faith or would not result in a Material Adverse Effect.

(z) Financial Statements. The financial statements (including the related notes
thereto) of the Company and its consolidated subsidiaries included or
incorporated by reference in the General Disclosure Package and the Final
Offering Circular comply in all material respects with the applicable
requirements of the Securities Act and the Exchange Act, as applicable, and
present fairly the financial position of the Company and its consolidated
subsidiaries as of the dates indicated and the results of their operations and
the changes in their cash flows for the periods specified; such financial
statements have been prepared in conformity with generally accepted accounting
principles applied on a consistent basis throughout the periods covered thereby,
and any supporting schedules included or incorporated by reference in the
General Disclosure Package and the Final Offering Circular present fairly the
information required to be stated therein; and the other financial information
included or incorporated by reference in the General Disclosure Package and the
Final Offering Circular has been derived from the accounting records of the
Company and its consolidated subsidiaries and presents fairly the information
shown thereby.

(aa) No Material Adverse Change. Since the date of the most recent financial
statements of the Company included or incorporated by reference in the General
Disclosure Package and the Final Offering Circular, (A) there has not been any
material change in the capital stock (other than the issuance of shares of
Common Stock upon exercise of stock options and warrants described as
outstanding in, and the grant of options and awards under existing equity
incentive plans described in, the General Disclosure Package and the Final
Offering Circular), short-term debt or long-term debt of the Company or any of
its subsidiaries, or any dividend or distribution of any kind declared, set
aside for payment, paid or made by the Company on any class of capital stock, or
any material adverse change, or any development involving a prospective material
adverse change, in or affecting the business, properties, management, financial
position, shareholders’ equity, results of operations or prospects of the
Company and its subsidiaries taken as a whole; (B) neither the Company nor any
of its subsidiaries has entered into any transaction or agreement (whether or
not in the ordinary course of business) that is material to the Company and its
subsidiaries taken as a whole or incurred any liability or obligation, direct or
contingent, that is material to the Company and its subsidiaries taken as a
whole; and (C) neither the Company nor any of its subsidiaries has sustained any
loss or interference with its business that is material to the Company and its
subsidiaries taken as a whole and that is either from fire, explosion, flood or
other calamity, whether or not covered by insurance, or from any labor
disturbance or dispute or any action, order or decree of any court or arbitrator
or governmental or regulatory authority, except in each case as otherwise
disclosed in the General Disclosure Package and the Final Offering Circular.

 

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(bb) Investment Company Act. The Company is not and, after giving effect to the
offering and sale of the Offered Securities and the application of the proceeds
thereof as described in the General Disclosure Package and the Final Offering
Circular, will not be required to register as an “investment company” or an
entity “controlled” by an “investment company” within the meaning of the
Investment Company Act of 1940, as amended, and the rules and regulations of the
Commission thereunder (collectively, the “Investment Company Act”).

(cc) Regulations T, U, X. The application of the proceeds received by the
Company from the issuance, sale and delivery of the Offered Securities as
described in the General Disclosure Package and the Final Offering Circular will
not violate Regulation T, U or X of the Board of Governors of the Federal
Reserve System or any other regulation of such Board of Governors.

(dd) Ratings. No “nationally recognized statistical rating organization” as such
term is defined for purposes of Rule 436(g)(2) (i) has imposed (or has informed
the Company that it is considering imposing) any condition (financial or
otherwise) on the Company’s retaining any rating assigned to the Company or any
securities of the Company or (ii) has indicated to the Company that it is
considering any of the actions described in Section 7(c)(ii) hereof.

(ee) Class of Securities Not Listed. No securities of the same class (within the
meaning of Rule 144A(d)(3)) as the Offered Securities are listed on any national
securities exchange registered under Section 6 of the Exchange Act or quoted in
a U.S. automated inter-dealer quotation system.

(ff) No Registration. The offer and sale of the Offered Securities in the manner
contemplated by this Agreement will be exempt from the registration requirements
of the Securities Act by reason of Section 4(2) thereof, Regulation D thereunder
and Regulation S thereunder.

(gg) No General Solicitation; No Directed Selling Efforts. Neither the Company,
nor any of its affiliates, nor any person acting on its or their behalf (i) has,
within the six-month period prior to the date hereof, offered or sold in the
United States or to any U.S. person (as such terms are defined in Regulation S
under the Securities Act) the Offered Securities or any security of the same
class or series as the Offered Securities or (ii) has offered or will offer or
sell the Offered Securities (A) in the United States by means of any form of
general solicitation or general advertising within the meaning of Rule 502(c) or
(B) with respect to any such securities sold in reliance on Rule 903 of
Regulation S (“Regulation S”) under the Securities Act, by means of any directed
selling efforts within the meaning of Rule 902(c) of Regulation S. The Company,
its affiliates and any person acting on its or their behalf have complied and
will comply with the offering restrictions requirement of Regulation S. The
Company has not entered and will not enter into any contractual arrangement with
respect to the distribution of the Offered Securities except for this Agreement.

(hh) Use of Proceeds. The proceeds to the Company from the offering of the
Offered Securities will not be used to purchase or carry any security.

(ii) Reporting Status. The Company is subject to Section 13 or 15(d) of the
Exchange Act.

(jj) Insurance. The Company and its subsidiaries have insurance covering their
respective properties, operations, personnel and businesses, including business
interruption insurance, which insurance is in amounts and insures against such
losses and risks as are customary for the businesses in which they are engaged;
all such policies insuring the Company

 

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and its subsidiaries are in full force and effect; and neither the Company nor
any of its subsidiaries has received notice from any insurer or agent of such
insurer that it will not be able to renew insurance coverage as and when such
coverage expires or to obtain coverage acceptable to the Company at reasonable
cost from similar insurers as may be necessary to continue its business.

(kk) Compliance with ERISA. The minimum funding standard under Section 302 of
the Employee Retirement Income Security Act of 1974, as amended, and the
regulations and published interpretations thereunder (“ERISA”), has been
satisfied by each “pension plan” (as defined in Section 3(2) of ERISA) which has
been established or maintained by the Company, and the trust forming part of
each such plan which is intended to be qualified under Section 401 of the
Internal Revenue Code of 1986, as amended (the “Code”), is so qualified; each of
the Company and each of its subsidiaries has fulfilled its obligations, if any,
under Section 515 of ERISA; neither the Company nor any of its subsidiaries
maintains and is required to contribute to a “welfare plan” (as defined in
Section 3(1) of ERISA) which provides retiree or other post-employment welfare
benefits or insurance coverage (other than “continuation coverage” (as defined
in Section 602 of ERISA)); each pension plan and welfare plan established or
maintained by the Company and/or one of the subsidiaries is in compliance with
the currently applicable provisions of ERISA, except where the failure to comply
would not cause a Material Adverse Effect; no prohibited transaction, within the
meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with
respect to any pension plan or welfare plan (excluding transactions effected
pursuant to statutory or administrative exemption) that could reasonably be
expected to result in a material liability to the Company or its subsidiaries;
and neither the Company nor any of its subsidiaries has incurred or could
reasonably be expected to incur any withdrawal liability under Section 4201 of
ERISA, any liability under Section 4062, 4063, or 4064 of ERISA, or any other
liability under Title IV of ERISA.

(ll) Reserve Report Data. The oil and gas reserve estimates of the Company
contained or incorporated by reference into the General Disclosure Package and
the Final Offering Circular have been prepared by (A) Ryder Scott Company, L.P.,
(B) Collarini Associates and (C) DeGolyer & MacNaughton (collectively, the
“Engineers”), and the Company has no reason to believe that such estimates do
not fairly reflect the oil and gas reserves of the Company at the dates
indicated. The information underlying the estimates of the reserves of the
Company and its subsidiaries supplied by the Company to the Engineers, for the
purposes of preparing the reserve reports of Company and its subsidiaries
referenced in the General Disclosure Package and the Final Offering Circular
(the “Reserve Reports”), was true and correct in all material respects on the
date of each such Reserve Report; the estimates of future capital expenditures
and other future exploration and development costs supplied to the Engineers
were prepared in good faith and with a reasonable basis; the information
provided to the Engineers was prepared in good faith and with a reasonable
basis. Other than production of the reserves in the ordinary course of business
and intervening product price fluctuations described in the General Disclosure
Package and the Final Offering Circular, the Company is not aware of any facts
or circumstances that would cause a Material Adverse Change in the reserves or
the present value of future net cash flows therefrom as described in the General
Disclosure Package and the Final Offering Circular. Each of the Engineers is an
independent reserve engineer with respect to the Company and its subsidiaries.

(mm) Related Party Transactions. All business relationships or related-party
transactions involving the Company or any of its subsidiaries or any of their
respective directors, managers, executive officers, nominees for election as
director, manager or executive officer, any security holder, member interest
holder or partnership interest holder, each as applicable, who is known to the
Company or any of its subsidiaries to own of record or beneficially more than
five percent of any class of the Company’s or any of its subsidiaries’ voting
securities or interests, as applicable, any member of the immediate family of
the foregoing persons, or any other person, required to be disclosed pursuant to
the requirements of Item 404 of Regulation S-K under the Securities Act, are
accurately described in the General Disclosure Package and the Final Offering
Circular, and all other related-party transactions required to be disclosed
pursuant to the requirements of Item 404 of Regulation S-K under the Securities
Act have been accurately described in the General Disclosure Package.

 

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(nn) Independent Accountants. PricewaterhouseCoopers LLP, who have certified
certain financial statements of the Company and its subsidiaries, and Deloitte &
Touche LLP, who have certified certain financial statements of the Company and
its subsidiaries, are each an independent registered public accounting firm with
respect to the Company and its subsidiaries within the applicable rules and
regulations adopted by the Commission and the Public Company Accounting
Oversight Board (United States) and as required by the Securities Act.

(oo) Incorporated Documents. The documents incorporated by reference in the
General Disclosure Package and the Final Offering Circular, when they were filed
with the Commission, conformed in all material respects to the requirements of
the Exchange Act, and none of such documents contained any untrue statement of a
material fact or omitted to state a material fact necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading; and any further documents so filed and incorporated by
reference in the General Disclosure Package and the Final Offering Circular,
when such documents are filed with the Commission, will conform in all material
respects to the requirements of the Exchange Act and will not contain any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements therein, in the light of the circumstances under which they were
made, not misleading.

(pp) No Unlawful Payments. Neither the Company nor any of its subsidiaries nor,
to the knowledge of the Company, any director, officer, agent, employee or other
person associated with or acting on behalf of the Company or any of its
subsidiaries has (A) used any corporate funds for any unlawful contribution,
gift, entertainment or other unlawful expense relating to political activity;
(B) made any direct or indirect unlawful payment to any foreign or domestic
government official or employee from corporate funds; (C) violated or is in
violation of any provision of the Foreign Corrupt Practices Act of 1977; or
(D) made any bribe, rebate, payoff, influence payment, kickback or other
unlawful payment.

(qq) Compliance with Money Laundering Laws. The operations of the Company and
its subsidiaries are and have been conducted at all times in compliance with
applicable financial recordkeeping and reporting requirements of the Currency
and Foreign Transactions Reporting Act of 1970, as amended, the money laundering
statutes of all jurisdictions, the rules and regulations thereunder and any
related or similar rules, regulations or guidelines, issued, administered or
enforced by any governmental agency (collectively, the “Money Laundering Laws”)
and no action, suit or proceeding by or before any court or governmental agency,
authority or body or any arbitrator involving the Company or any of its
subsidiaries with respect to the Money Laundering Laws is pending or, to the
knowledge of the Company, threatened.

(rr) Compliance with OFAC. None of the Company, any of its subsidiaries or, to
the knowledge of the Company, any director, officer, agent, employee or
affiliate of the Company or any of its subsidiaries is currently subject to any
U.S. sanctions administered by the Office of Foreign Assets Control of the U.S.
Department of the Treasury (“OFAC”); and the Company will not, directly or
indirectly, use the proceeds of the offering of the Offered Securities
hereunder, or lend, contribute or otherwise make available such proceeds to any
subsidiary, joint venture partner or other person or entity, for the purpose of
financing the activities of any person currently subject to any U.S. sanctions
administered by OFAC.

(ss) No Restrictions on Subsidiaries. No subsidiary of the Company that is a
party to the Credit Agreement, dated June 27, 2008 to which the Company is a
party, is currently prohibited, directly or indirectly, under any agreement or
other instrument to which it is a party or is subject, from paying any dividends
to the Company, from making any other distribution on such subsidiary’s capital
stock, from repaying to the Company any loans or advances to such subsidiary
from the Company or from transferring any of such subsidiary’s properties or
assets to the Company or any other subsidiary of the Company.

 

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3. Purchase, Sale and Delivery of Offered Securities. On the basis of the
representations, warranties and agreements and subject to the terms and
conditions set forth herein, the Company agrees to sell to the several
Purchasers, and each of the Purchasers agrees, severally and not jointly, to
purchase from the Company, at a purchase price of U.S. $97.00 per share plus
accumulated dividends from September 29, 2009 to the First Closing Date (as
hereinafter defined), the respective number of shares of Firm Securities set
forth opposite the names of the several Purchasers in Schedule A hereto.

The Company will deliver the Firm Securities to or as instructed by the
Representatives for the accounts of the several Purchasers in a form reasonably
acceptable to the Representatives against payment of the purchase price by the
Purchasers in Federal (same day) funds by wire transfer to an account at a bank
acceptable to the Representatives drawn to the order of the Company at the
office of Cahill Gordon & Reindell LLP, at 10 a.m., New York City time, on
September 29, 2009 or at such other time not later than seven full business days
thereafter as the Representatives and the Company determine, such time being
herein referred to as the “First Closing Date”. The Offered Securities so to be
delivered or evidence of their issuance will be made available for checking at
the above office of Cahill Gordon & Reindell LLP at least 24 hours prior to the
First Closing Date.

In addition, upon written notice from the Representatives given to the Company
from time to time not more than 30 days subsequent to the date of this
Agreement, the Purchasers may purchase all or less than all of the Optional
Securities at the purchase price per Offered Security (including any accumulated
dividends thereon to the related Optional Closing Date) to be paid for the Firm
Securities. The Company agrees to sell to the Purchasers the number of Optional
Securities specified in such notice and the Purchasers agree, severally and not
jointly, to purchase such Optional Securities. Such Optional Securities shall be
purchased from the Company for the account of each Purchaser in the same
proportion as the number of Firm Securities set forth opposite such Purchaser’s
name in Schedule A hereto bears to the total number of Firm Securities (subject
to adjustment by the Representatives to eliminate fractions). No Optional
Securities shall be sold or delivered unless the Firm Securities previously have
been, or simultaneously are, sold and delivered. The right to purchase the
Optional Securities or any portion thereof may be exercised from time to time
and to the extent not previously exercised may be surrendered and terminated at
any time upon notice by the Representatives to the Company.

Each time for the delivery of and payment for the Optional Securities, being
herein referred to as the “Optional Closing Date”, which may be the First
Closing Date (the First Closing Date and each Optional Closing Date, if any,
being sometimes referred to as a “Closing Date”), shall be determined by the
Representatives on behalf of the several Purchasers but shall not be later than
seven full business days after written notice of election to purchase Optional
Securities is given. Payment for the Optional Securities being purchased on each
Optional Closing Date shall be made by the Purchasers in United States dollars
in Federal (same day) funds by wire transfer to an account at a bank acceptable
to the Representatives drawn to the order of the Company at 10:00 a.m. (New York
City time) on the Optional Closing Date against delivery to or as instructed by
the Representatives for the account of the several Purchasers of the Optional
Securities in a form reasonably acceptable to the Representatives. The Optional
Securities being purchased on each Optional Closing Date or evidence of their
issuance will be made available for checking at the above offices of Cahill
Gordon & Reindell LLP at a reasonable time in advance of such Optional Closing
Date.

4. Representations by Purchasers; Resale by Purchasers. (a) Each Purchaser
severally represents and warrants to the Company that it is an “accredited
investor” within the meaning of Regulation D under the Securities Act.

(b) Each Purchaser severally acknowledges that the Offered Securities have not
been registered under the Securities Act and may not be offered or sold within
the United States or to, or for the account or benefit of, U.S. persons except
in accordance with Regulation S or pursuant to an exemption from the
registration requirements of the Securities Act. Each Purchaser

 

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severally represents and agrees that it has offered and sold the Offered
Securities, and will offer and sell the Offered Securities, only in accordance
with Rule 903 or Rule 144A. Accordingly, neither such Purchaser nor its
affiliates, nor any persons acting on its or their behalf, have engaged or will
engage in any directed selling efforts with respect to the Offered Securities,
and such Purchaser, its affiliates and all persons acting on its or their behalf
have complied and will comply with the offering restrictions requirement of
Regulation S and Rule 144A.

(c) Each Purchaser agrees that it and each of its affiliates has not entered and
will not enter into any contractual arrangement with respect to the distribution
of the Offered Securities except with the prior written consent of the Company.

(d) Each Purchaser agrees that it and each of its affiliates will not offer or
sell the Offered Securities in the United States by means of any form of general
solicitation or general advertising within the meaning of Rule 502(c),
including, but not limited to (i) any advertisement, article, notice or other
communication published in any newspaper, magazine or similar media or broadcast
over television or radio, or (ii) any seminar or meeting whose attendees have
been invited by any general solicitation or general advertising. Each Purchaser
agrees, with respect to resales made in reliance on Rule 144A of any of the
Offered Securities, to deliver either with the confirmation of such resale or
otherwise prior to settlement of such resale a notice to the effect that the
resale of such Offered Securities has been made in reliance upon the exemption
from the registration requirements of the Securities Act provided by Rule 144A.

(e) Each Purchaser acknowledges and agrees that the Company and, for the purpose
of the opinions to be delivered to the Purchasers pursuant to Sections 7(d) and
(e), counsel for the Company and counsel for the Purchasers, respectively, may
rely on the accuracy of the representations and warranties of the Purchasers,
and compliance by the Purchasers with their agreements contained in paragraph
(d) above, and each Purchaser hereby consents to such reliance.

5. Certain Agreements of the Company. The Company agrees with the several
Purchasers that:

(a) Amendments and Supplements to Offering Circulars. The Company will promptly
advise the Representatives of any proposal to amend or supplement the
Preliminary or Final Offering Circular and will not effect such amendment or
supplementation without the Representatives’ consent. If, at any time prior to
the completion of the resale of the Offered Securities by the Purchasers, there
occurs an event or development as a result of which any document included in the
Preliminary or Final Offering Circular, the General Disclosure Package or any
Supplemental Marketing Material, if republished immediately following such event
or development, included or would include an untrue statement of a material fact
or omitted or would omit to state any material fact necessary in order to make
the statements therein, in the light of the circumstances under which they were
made, not misleading, or if it is necessary at any such time to amend or
supplement the Preliminary or Final Offering Circular, the General Disclosure
Package or any Supplemental Marketing Material to comply with any applicable
law, the Company promptly will notify the Representatives of such event and
promptly will prepare and furnish, at its own expense, to the Purchasers and to
any other dealers at the request of the Representatives, an amendment or
supplement which will correct such statement or omission. Neither the
Representatives’ consent to, nor their delivery to offerees or investors of, any
such amendment or supplement shall constitute a waiver of any of the conditions
set forth in Section 7.

(b) Furnishing of Offering Circulars. The Company will furnish to the
Representatives copies of the Preliminary Offering Circular, each other document
comprising a part of the General Disclosure Package, the Final Offering
Circular, all amendments and supplements to such documents and each item of
Supplemental Marketing Material, in each case as soon as available and in such
quantities as the Representatives request, and the Company will furnish to the
Representatives on the date hereof three copies of each of the foregoing
documents signed by a duly authorized officer of the Company, one of which in
the case of the Preliminary Offering

 

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Circular and the Final Offering Circular will include the independent
accountants’ reports manually signed by such independent accountants. At any
time when the Company is not subject to Section 13 or 15(d) of the Exchange Act,
the Company will promptly furnish or cause to be furnished to the Purchasers
and, upon request of holders and prospective purchasers of the Offered
Securities, to such holders and purchasers, copies of the information required
to be delivered to holders and prospective purchasers of the Offered Securities
pursuant to Rule 144A(d)(4) (or any successor provision thereto) in order to
permit compliance with Rule 144A in connection with resales by such holders of
the Offered Securities. The Company will pay the expenses of printing and
distributing to the Purchasers all such documents.

(c) Blue Sky Qualifications. The Company will arrange for the qualification of
the Offered Securities and the Underlying Shares for sale and the determination
of their eligibility for investment under the laws of such jurisdictions in the
United States and Canada as the Representatives designate and will continue such
qualifications in effect so long as required for the resale of the Offered
Securities by the Purchasers, provided that the Company shall not be required to
(i) qualify as a foreign corporation or other entity or as a dealer in
securities in any such jurisdiction where it would not otherwise be required to
so qualify, (ii) file any general consent to service of process in any such
jurisdiction or (iii) subject itself to taxation in any such jurisdiction if it
is not otherwise so subject.

(d) Reporting Requirements. For so long as the Offered Securities remain
outstanding, the Company will furnish to each Purchaser as soon as practicable
after the end of each fiscal year, a copy of its annual report to shareholders
for such year; and the Company will furnish to such Purchaser (i) as soon as
available, a copy of each report and any definitive proxy statement of the
Company filed with the Commission under the Exchange Act or mailed to
shareholders, and (ii) from time to time, such other information concerning the
Company as such Purchaser may reasonably request. However, so long as the
Company is subject to the reporting requirements of either Section 13 or
Section 15(d) of the Exchange Act and is timely filing reports with the
Commission on its Electronic Data Gathering, Analysis and Retrieval system
(“EDGAR”), it is not required to furnish such reports or statements to the
Purchaser.

(e) Transfer Restrictions. During the period of one year after the later of the
First Closing Date and the last Optional Closing Date, the Company will, upon
request, furnish to each Purchaser and any holder of Offered Securities a copy
of the restrictions on transfer applicable to the Offered Securities.

(f) No Resales by Affiliates. During the period of one year after the later of
the First Closing Date and the last Optional Closing Date, the Company will not,
and will not permit any of its affiliates (as defined in Rule 144) to, resell
any of the Offered Securities that have been reacquired by any of them.

(g) Investment Company. During the period of two years after the later of the
First Closing Date and the last Optional Closing Date, the Company will not be,
or become, an open-end investment company, unit investment trust or face-amount
certificate company that is or is required to be registered under Section 8 of
the Investment Company Act.

(h) Payment of Expenses. The Company will pay all expenses incidental to the
performance of its obligations under this Agreement, including but not limited
to (i) all expenses in connection with the execution, issue, authentication,
packaging and initial delivery of the Offered Securities, the preparation and
printing of this Agreement, the Offered Securities, the Preliminary Offering
Circular, any other documents comprising any part of the General Disclosure
Package, the Final Offering Circular, all amendments and supplements thereto,
each item of Supplemental Marketing Material and any other document relating to
the issuance, offer, sale and delivery of the Offered Securities; (ii) the cost
of any advertising approved by the Company in connection with the issue of the
Offered Securities; (iii) any expenses (including fees and disbursements of
counsel to the Purchasers) incurred in connection with qualification of the

 

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Offered Securities for sale under the laws of such jurisdictions in the United
States and Canada as the Purchasers designate and the preparation and printing
of memoranda relating thereto, (iv) any fees charged by investment rating
agencies for the rating of the Offered Securities, and (v) expenses incurred in
distributing the Preliminary Offering Circular, any other documents comprising
any part of the General Disclosure Package, the Final Offering Circular
(including any amendments and supplements thereto) and any Supplemental
Marketing Material to the Purchasers. The Company will also pay or reimburse the
Purchasers (to the extent incurred by them) for costs and expenses of the
Purchasers and the Company’s officers and employees and any other expenses of
the Purchasers and the Company relating to investor presentations on any “road
show” in connection with the offering and sale of the Offered Securities
including, without limitation, any travel expenses of the Company’s officers and
employees and any other expenses of the Company including the chartering of
airplanes.

(i) Use of Proceeds. The Company will use the net proceeds received in
connection with this offering in the manner described in the “Use of Proceeds”
section of the General Disclosure Package and the Final Offering Circular and,
except as disclosed in the General Disclosure Package and the Final Offering
Circular, the Company does not intend to use any of the proceeds from the sale
of the Offered Securities hereunder to repay any outstanding debt owed to any
affiliate of any Purchaser.

(j) Absence of Manipulation. In connection with the offering, until the
Representatives shall have notified the Company and the other Purchasers of the
completion of the resale of the Offered Securities, neither the Company nor any
of its affiliates will, either alone or with one or more other persons, bid for
or purchase for any account in which it or any of its affiliates has a
beneficial interest any Offered Securities or attempt to induce any person to
purchase any Offered Securities; and neither it nor any of its affiliates will
make bids or purchases for the purpose of creating actual, or apparent, active
trading in, or of raising the price of, the Offered Securities.

(k) Restriction on Sale of Securities. For a period of 90 days after the date of
the Final Offering Circular, the Company will not (i) offer, pledge, announce
the intention to sell, sell, contract to sell, sell any option or contract to
purchase, purchase any option or contract to sell, grant any option, right or
warrant to purchase or otherwise transfer or dispose of, directly or indirectly,
the Offered Securities, any shares of Common Stock or any securities convertible
into or exercisable or exchangeable for Common Stock (other than the concurrent
offering of shares as described in the General Disclosure Package and the Final
Offering Circular) or (ii) enter into any swap or other agreement that
transfers, in whole or in part, any of the economic consequences of ownership of
the Offered Securities or the Common Stock, whether any such transaction
described in clause (i) or (ii) above is to be settled by delivery of Common
Stock or such other securities, in cash or otherwise, without the prior written
consent of the Representatives, other than the Offered Securities to be sold
hereunder and any shares of Common Stock of the Company issued upon the exercise
of options granted under stock option plans described in the General Disclosure
Package and the Final Offering Circular. Notwithstanding the foregoing, if
(1) during the last 17 days of the 90-day restricted period, the Company issues
an earnings release or material news or a material event relating to the Company
occurs; or (2) prior to the expiration of the 90-day restricted period, the
Company announces that it will release earnings results during the 16-day period
beginning on the last day of the 90-day period, the restrictions imposed by this
Agreement shall continue to apply until the expiration of the 18-day period
beginning on the issuance of the earnings release or the occurrence of the
material news or material event.

6. Free Writing Communications. (a) Issuer Free Writing Communications. The
Company represents and agrees that, unless it obtains the prior consent of the
Representatives, it has not made and will not make any offer relating to the
Offered Securities that would constitute an Issuer Free Writing Communication.

(b) Term Sheets. The Company consents to the use by any Purchaser of a Free
Writing Communication that (i) contains only (A) information describing the
preliminary terms of the

 

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Offered Securities or their offering or (B) information that describes the final
terms of the Offered Securities or their offering and that is included in or is
subsequently included in the Final Offering Circular or (ii) does not contain
any material information about the Company or its securities that was provided
by or on behalf of the Company, it being understood and agreed that the Company
shall not be responsible to any Purchaser for liability arising from any
inaccuracy in such Free Writing Communications referred to in clause (i) or
(ii) as compared with the information in the Preliminary Offering Circular, the
Final Offering Circular or the General Disclosure Package.

7. Conditions of the Obligations of the Purchaser. The obligations of the
several Purchasers to purchase and pay for the Firm Securities on the First
Closing Date and for the Optional Securities on each Optional Closing Date will
be subject to the accuracy of the representations and warranties of the Company
herein (as though made on such Closing Date), to the accuracy of the statements
of officers of the Company made pursuant to the provisions hereof, to the
performance by the Company of its obligations hereunder and to the following
additional conditions precedent:

(a) Accountants’ Comfort Letter. The Purchasers shall have received letters
(A) on the date hereof, from PricewaterhouseCoopers LLP and Deloitte & Touche
LLP, dated the date hereof, and (B) on each Closing Date, from
PricewaterhouseCoopers LLP, dated as of such Closing date, confirming that they
are a registered public accounting firm and independent public accountants
within the meaning of the Securities Laws and substantially in the form of
Schedule D hereto (except that, in any letter dated a Closing Date, the
specified date referred to in Schedule D hereto shall be of a date no more than
three days prior to such Closing Date).

(b) Reserve Engineers’ Letters. The Purchasers shall have received a letter
dated the date hereof and such Closing Date, of each of Ryder Scott Company,
L.P. and Collarini Associates (i) confirming that as of the date of its Reserve
Reports, it was an independent reserve engineer for the Company and/or its
subsidiaries and that as of the date of such letter no information has come to
its attention that could reasonably be expected to cause it to withdraw its
Reserve Report and (ii) otherwise in form and substance acceptable to the
Purchasers.

(c) No Material Adverse Change. Subsequent to the execution and delivery of this
Agreement, there shall not have occurred (i) any change, or any development or
event involving a prospective change, in the condition (financial or otherwise),
results of operations, business, properties or prospects of the Company and its
subsidiaries taken as a whole which, in the judgment of the Representatives, is
material and adverse and makes it impractical or inadvisable to market the
Offered Securities; (ii) any downgrading in the rating of any debt securities or
preferred stock of the Company by any “nationally recognized statistical rating
organization” (as defined for purposes of Rule 436(g)), or any public
announcement that any such organization has under surveillance or review its
rating of any debt securities or preferred stock of the Company (other than an
announcement with positive implications of a possible upgrading, and no
implication of a possible downgrading, of such rating); (iii) any change in U.S.
or international financial, political or economic conditions or currency
exchange rates or exchange controls the effect of which is such as to make it,
in the judgment of the Representatives, impractical to market or to enforce
contracts for the sale of the Offered Securities, whether in the primary market
or in respect of dealings in the secondary market, (iv) any suspension or
material limitation of trading in securities generally on the New York Stock
Exchange or the Nasdaq Global Select Market, or any setting of minimum or
maximum prices for trading on such exchange; (v) any suspension of trading of
any securities of the Company on any exchange or in the over-the-counter market;
(vi) any banking moratorium declared by any U.S. Federal or New York
authorities; (vii) any major disruption of settlements of securities, payment,
or clearance services in the United States or any other country where such
securities are listed or (viii) any attack on, outbreak or escalation of
hostilities or act of terrorism involving the United States, any declaration of
war by Congress or any other national or international calamity or emergency if,
in the judgment of the Representatives, the effect of any such attack, outbreak,
escalation, act, declaration, calamity or emergency is such as to make it in the
judgment of the Representatives impractical or inadvisable to market the Offered
Securities or to enforce contracts for the sale of the Offered Securities.

 

16

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(d) Opinion of Counsel for Company. The Purchasers shall have received an
opinion, dated such Closing Date, of Jackson Walker L.L.P., counsel for the
Company that:

(i) Good Standing of the Company. The Company has been duly incorporated and is
existing and in good standing under the laws of the State of Texas, with
corporate power and authority to own its properties and conduct its business as
described in the General Disclosure Package, the Final Offering Circular and
Exchange Act Reports;

(ii) Offered Securities. The Offered Securities delivered on such Closing Date
have been duly authorized and validly issued, are fully paid and nonassessable
and conform to the description thereof contained in the General Disclosure
Package and the Final Offering Circular; and the shareholders of the Company
have no statutory preemptive rights with respect to the Offered Securities;

(iii) Underlying Shares. The Offered Securities delivered on such Closing Date
are convertible into Common Stock of the Company in accordance with their terms;
the shares of such Common Stock initially issuable upon conversion of the
Offered Securities delivered on such Closing Date have been duly authorized and
reserved for issuance upon such conversion and conform to the description of
such Common Stock contained in the General Disclosure Package and the Final
Offering Circular; the shareholders of the Company have no statutory preemptive
rights with respect to the issuance of the Underlying Shares upon the conversion
of the Offered Securities in any case pursuant to the Company’s Amended and
Restated Articles of Incorporation, the Amended and Restated Bylaws, as amended,
the Texas Business Corporation Act; and all Underlying Shares, when issued upon
conversion of the Offered Securities, will be validly issued, fully paid and
nonassessable;

(iv) Investment Company. The Company is not and, after giving effect to the
offering and sale of the Offered Securities and the application of the proceeds
thereof as described in the General Disclosure Package, will not be an
“investment company” as defined in the Investment Company Act;

(v) Absence of Further Requirements. No consent, approval, authorization, order,
license, registration or qualification of or with any court or arbitrator or
governmental or regulatory authority is required for the execution, delivery and
performance of this Agreement and the consummation of the transactions
contemplated by this Agreement in connection with the offering, issuance and
sale of the Offered Securities and Underlying Shares by the Company, except such
as have been or will be obtained prior to the consummation of the offering;

(vi) Litigation. Based solely on counsel’s review of the information set forth
in the certificates of officers of the Company delivered to counsel in
connection with such opinion, which review is approved by Purchasers, counsel
has no knowledge of any material actions, suits, proceedings or investigations
pending or threatened against or affecting the Company or its property in any
court or before any governmental agency;

(vii) Absence of Defaults and Conflicts Resulting from Transaction. The
execution, delivery and performance of this Agreement and the issuance and sale
of the Offered Securities and the Underlying Shares and the consummation of the
transactions contemplated by this Agreement will not (a) breach, conflict with
or violate, or necessitate any filing or registration under (i) any Texas or
Federal law, (ii) any order, writ, judgment, injunction, decree, determination
or award known to counsel for the Company to be applicable to the Company or any
property of the Company or (iii) any provisions of the Restated Articles of
Incorporation or the Amended and Restated Bylaws of the Company, or (b) breach
or conflict with any indenture, instrument or other agreement filed as an
exhibit to the Company’s Annual Report on Form 10-K for the year ended
December 31, 2008;

 

17

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(viii) Disclosure. No information has come to such counsel’s attention that
leads it to believe that the Final Offering Circular as of its date and as of
such Closing Date, contained any untrue statement of a material fact or omitted
to state any material fact necessary to make the statements therein not
misleading; such counsel have no reason to believe that the General Disclosure
Package, as of the Applicable Time and as of such Closing Date, contained any
untrue statement of a material fact necessary to make the statements therein not
misleading; it being understood that such counsel need express no opinion as to
the financial statements, other financial data, representations and warranties
and other statements of fact included in the exhibits to the Exchange Act
Reports incorporated by reference to the Final Offering Circular or oil and
natural gas reserve information contained in the General Disclosure Package, the
Final Offering Circular and the Exchange Act Reports;

(ix) Authorization of Agreement. This Agreement has been duly authorized,
executed and delivered by the Company;

(x) Accurate Disclosure. The statements in the General Disclosure Package and
the Final Offering Circular under the headings “Certain U.S. Federal Income Tax
Considerations”, “Description of Convertible Preferred Stock”, and “Description
of Capital Stock” insofar as such statements purport to summarize certain
provisions of the documents and legal matters referred to therein, fairly
summarize such provisions and legal matters in all material respects, subject to
the qualifications and assumptions stated therein; and

(xi) No Registration. Assuming (i) the accuracy of the representations and
warranties of the Company set forth in Section 1 hereof, (ii) the due
performance by the Company and the Purchasers of the covenants and agreements
set forth in this Agreement, (iii) the compliance by the Purchasers with the
offering and transfer procedures and the restrictions described in the Final
Offering Circular, (iv) the accuracy of the representations and warranties of
the Purchasers set forth in Section 4 hereof, (v) the accuracy of the
representations and warranties made or deemed to be made in accordance with this
Agreement and the Final Offering Circular by purchasers to whom the Purchasers
initially resell the Offered Securities, and (vi) that purchasers to whom the
Purchasers initially resell the Offered Securities have been made aware of the
information set forth in the Final Offering Circular under the caption “Transfer
Restrictions”, (A) the offer, issue, sale and delivery of the Offered Securities
to the Purchasers and the initial resale of the Offered Securities by the
Purchasers, each in the manner contemplated by this Agreement and the Final
Offering Circular, and (B) the issuance of Underlying Shares to holders of the
Offered Securities upon conversion thereof in accordance with the terms of the
Statement of Resolutions, do not require registration under the Securities Act;
provided, however, that such counsel need express no opinion as to any
subsequent resale or other transfer of any Offered Securities or any Underlying
Shares.

(e) Opinions of Counsel for Purchasers. The Purchasers shall have received from
each of Cahill Gordon & Reindel LLP and Cravath, Swaine & Moore LLP, counsel for
the Purchasers, such opinion or opinions, dated such Closing Date, with respect
to such matters as the Purchasers may require, and the Company shall have
furnished to such counsel such documents as they request for the purpose of
enabling them to pass upon such matters.

(f) Officers’ Certificate. The Purchasers shall have received a certificate,
dated such Closing Date, of an executive officer of the Company and a principal
financial or accounting officer of the Company in which such officers shall
state that the representations and warranties of the Company in this Agreement
are true and correct, that the Company has complied with all

 

18

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agreements and satisfied all conditions on its part to be performed or satisfied
hereunder at or prior to such Closing Date, and that, subsequent to the
respective dates of the most recent financial statements in the General
Disclosure Package and Exchange Act Reports and there has been no material
adverse change, nor any development or event involving a prospective material
adverse change, in the condition (financial or otherwise), results of
operations, business, properties or prospects of the Company and its
subsidiaries taken as a whole except as set forth in the General Disclosure
Package and Exchange Act Reports or as described in such certificate.

(g) Lockup Letters. On or prior to the date hereof, the Purchasers shall have
received lockup letters from each of the directors of the Company and each of
the executive officers of the Company that is a reporting person under
Section 16 of the Exchange Act.

(h) No Downgrade. Subsequent to the earlier of (A) the Applicable Time and
(B) the execution and delivery of this Agreement, if there are any debt
securities or preferred stock of, or guaranteed by, the Company or any of its
subsidiaries that are rated by a “nationally recognized statistical rating
organization,” as such term is defined by the Commission for purposes of Rule
436(g)(2) under the Securities Act, (i) no downgrading shall have occurred in
the rating accorded any such debt securities or preferred stock and (ii) no such
organization shall have publicly announced that it has under surveillance or
review, or has changed its outlook with respect to, its rating of any such debt
securities or preferred stock (other than an announcement with positive
implications of a possible upgrading).

(i) Chief Financial Officer’s Certificate. The Purchasers shall have received on
and as of such Closing Date a certificate of the Chief Financial Officer of the
Company to the effect that as of such Closing Date in the form and substance
reasonably satisfactory to the Representatives, to the effect set forth in
Exhibit A hereto.

(j) No Legal Impediment to Issuance. No action shall have been taken and no
statute, rule, regulation or order shall have been enacted, adopted or issued by
any federal, state or foreign governmental or regulatory authority that would as
of such Closing Date prevent the issuance or sale of the Offered Securities; and
no injunction or order of any federal, state or foreign court shall have been
issued that would as of such Closing Date prevent the issuance or sale of the
Offered Securities.

(k) Good Standing. The Representatives shall have received on and as of such
Closing Date satisfactory evidence of the good standing of the Company in
writing or any standard form of telecommunication from the appropriate
governmental authorities of such jurisdictions.

Documents described as being “in the agreed form” are documents which are in the
forms which have been initialed for the purpose of identification by Cahill
Gordon & Reindell LLP and Cravath, Swaine & Moore LLP, copies of which are held
by the Company and the Representatives, with such changes as the Representatives
may approve.

The Company will furnish the Purchasers with such conformed copies of such
opinions, certificates, letters and documents as the Purchasers reasonably
request. The Representatives may in their sole discretion waive on behalf of the
Purchasers compliance with any conditions to the obligations of the Purchasers
hereunder, whether in respect of an Optional Closing Date or otherwise.

8. Indemnification and Contribution. (a) Indemnification of Purchasers. The
Company will indemnify and hold harmless each Purchaser, its officers,
employees, agents, partners, members, directors and its affiliates and each
person, if any, who controls such Purchaser within the meaning of Section 15 of
the Securities Act or Section 20 of the Exchange Act (each, an “Indemnified
Party”), against any and all losses, claims, damages or liabilities, joint or
several, to which such Indemnified Party may become subject, under the
Securities Act, the Exchange Act, other Federal or state statutory law or
regulation or otherwise, insofar as such losses, claims, damages or liabilities
(or actions in respect thereof) arise out of or

 

19

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are based upon any untrue statement or alleged untrue statement of any material
fact contained in the Preliminary Offering Circular or the Final Offering
Circular, in each case as amended or supplemented, or any Issuer Free Writing
Communication (including, without limitation, any Supplemental Marketing
Material) or the Exchange Act Reports, or arise out of or are based upon the
omission or alleged omission of a material fact necessary in order to make the
statements therein, in the light of the circumstances under which they were
made, not misleading and will reimburse each Indemnified Party for any legal or
other expenses reasonably incurred by such Indemnified Party in connection with
investigating, preparing or defending against any loss, claim, damage,
liability, action, litigation, investigation or proceeding whatsoever (whether
or not such Indemnified Party is a party thereto) whether threatened or
commenced and in connection with the enforcement of this provision with respect
to any of the above as such expenses are incurred; provided, however, that the
Company will not be liable in any such case to the extent that any such loss,
claim, damage or liability arises out of or is based upon an untrue statement or
alleged untrue statement in or omission or alleged omission from any of such
documents in reliance upon and in conformity with written information furnished
to the Company by any Purchaser through the Representatives specifically for use
therein, it being understood and agreed that the only such information consists
of the information described as such in subsection (b) below.

(b) Indemnification of Company. Each Purchaser will severally and not jointly
indemnify and hold harmless the Company, each of its directors and officers and
each person, if any, who controls the Company within the meaning of Section 15
of the Securities Act or Section 20 of the Exchange Act (each, a “Purchaser
Indemnified Party”), against any losses, claims, damages or liabilities to which
such Purchaser Indemnified Party may become subject, under the Securities Act,
the Exchange Act, other Federal or state statutory law or regulation or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any untrue statement or alleged
untrue statement of any material fact contained in the Preliminary Offering
Circular or the Final Offering Circular, in each case as amended or
supplemented, or any Issuer Free Writing Communication or arise out of or are
based upon the omission or the alleged omission of a material fact necessary in
order to make the statements therein, in the light of the circumstances under
which they were made, not misleading, in each case to the extent, but only to
the extent, that such untrue statement or alleged untrue statement or omission
or alleged omission was made in reliance upon and in conformity with written
information furnished to the Company by such Purchaser through the
Representatives specifically for use therein, and will reimburse any legal or
other expenses reasonably incurred by such Purchaser Indemnified Party in
connection with investigating, preparing or defending against any such loss,
claim, damage, liability, action, litigation, investigation or proceeding
whatsoever (whether or not such Purchaser Indemnified Party is a party thereto)
whether threatened or commenced based upon any such untrue statement or
omission, or any such alleged untrue statement or omission as such expenses are
incurred, it being understood and agreed that the only such information
furnished by any Purchaser consists of the following information in the
Preliminary and Final Offering Circular: under the caption “Plan of
Distribution” the first sentence of paragraph three, the second sentence of
paragraph nine and paragraph ten; provided, however, that the Purchaser shall
not be liable for any losses, claims, damages or liabilities arising out of or
based upon the Company’s failure to perform its obligations under Section 5(a)
of this Agreement.

(c) Actions against Parties; Notification. Promptly after receipt by an
indemnified party under this Section of notice of the commencement of any
action, such indemnified party will, if a claim in respect thereof is to be made
against the indemnifying party under subsection (a) or (b) above, notify the
indemnifying party of the commencement thereof; provided that the failure to
notify the indemnifying party shall not relieve it from any liability that it
may have under subsection (a) or (b) above except to the extent that it has been
materially prejudiced (through the forfeiture of substantive rights or defenses)
by such failure; and provided further that the failure to notify the
indemnifying party shall not relieve it from any liability that it may have to
an indemnified party otherwise than under subsection (a) or (b) above. In case
any such action is brought against any indemnified party and it notifies the
indemnifying party of the commencement thereof, the indemnifying party will be
entitled to participate therein and, to the extent that it may wish, jointly
with any other indemnifying party similarly notified, to assume the defense
thereof, with counsel satisfactory to such indemnified party (who shall not,
except with the consent of the indemnified party, be counsel to the indemnifying
party), and after notice from the indemnifying party to such indemnified party
of its election so to assume the defense thereof, the indemnifying party will
not be

 

20

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liable to such indemnified party under this Section for any legal or other
expenses subsequently incurred by such indemnified party in connection with the
defense thereof other than reasonable costs of investigation. No indemnifying
party shall, without the prior written consent of the indemnified party, effect
any settlement of any pending or threatened action in respect of which any
indemnified party is or could have been a party and indemnity could have been
sought hereunder by such indemnified party unless such settlement includes
(i) an unconditional release of such indemnified party from all liability on any
claims that are the subject matter of such action and (ii) does not include a
statement as to or an admission of fault, culpability or failure to act by or on
behalf of any indemnified party.

(d) Contribution. If the indemnification provided for in this Section is
unavailable or insufficient to hold harmless an indemnified party under
subsection (a) or (b) above, then each indemnifying party shall contribute to
the amount paid or payable by such indemnified party as a result of the losses,
claims, damages or liabilities referred to in subsection (a) or (b) above (i) in
such proportion as is appropriate to reflect the relative benefits received by
the Company on the one hand and the Purchasers on the other from the offering of
the Offered Securities or (ii) if the allocation provided by clause (i) above is
not permitted by applicable law, in such proportion as is appropriate to reflect
not only the relative benefits referred to in clause (i) above but also the
relative fault of the Company on the one hand and the Purchasers on the other in
connection with the statements or omissions which resulted in such losses,
claims, damages or liabilities as well as any other relevant equitable
considerations. The relative benefits received by the Company on the one hand
and the Purchasers on the other shall be deemed to be in the same proportion as
the total net proceeds from the offering (before deducting expenses) received by
the Company bear to the total discounts and commissions received by the
Purchasers from the Company under this Agreement. The relative fault shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission or alleged omission to state
a material fact relates to information supplied by the Company or the Purchasers
and the parties’ relative intent, knowledge, access to information and
opportunity to correct or prevent such untrue statement or omission. The amount
paid by an indemnified party as a result of the losses, claims, damages or
liabilities referred to in the first sentence of this subsection (d) shall be
deemed to include any legal or other expenses reasonably incurred by such
indemnified party in connection with investigating or defending any action or
claim which is the subject of this subsection (d). Notwithstanding the
provisions of this subsection (d), no Purchaser shall be required to contribute
any amount in excess of the amount by which the total price at which the Offered
Securities purchased by it were resold exceeds the amount of any damages which
such Purchaser has otherwise been required to pay by reason of such untrue or
alleged untrue statement or omission or alleged omission. The Company and the
Purchasers agree that it would not be just and equitable if contribution
pursuant to this Section 8(d) were determined by pro rata allocation (even if
the Purchasers were treated as one entity for such purpose) or by any other
method of allocation which does not take account of the equitable considerations
referred to in this Section 8(d).

9. Default of Purchasers. If any Purchaser or Purchasers default in their
obligations to purchase Offered Securities hereunder on either the First Closing
Date or any Optional Closing Date and the aggregate number of Offered Securities
that such defaulting Purchaser or Purchasers agreed but failed to purchase does
not exceed 10% of the total number of Offered Securities that the Purchasers are
obligated to purchase on such Closing Date, the Representatives may make
arrangements satisfactory to the Company for the purchase of such Offered
Securities by other persons, including any of the Purchasers, but if no such
arrangements are made by such Closing Date, the non-defaulting Purchasers shall
be obligated severally, in proportion to their respective commitments hereunder,
to purchase the Offered Securities that such defaulting Purchasers agreed but
failed to purchase on such Closing Date. If any Purchaser or Purchasers so
default and the aggregate number of Offered Securities with respect to which
such default or defaults occur exceeds 10% of the total number of shares of
Offered Securities that the Purchasers are obligated to purchase on such Closing
Date and arrangements satisfactory to the Representatives and the Company for
the purchase of such Offered Securities by other persons are not made within
36 hours after such default, this Agreement will terminate without liability on
the part of any non-defaulting Purchaser or the Company, except as provided in
Section 10 (provided that if such default occurs with respect to Optional
Securities after the First Closing Date, this Agreement shall not terminate as
to the Firm Securities or any Optional Securities purchased prior to such
termination). As used in this Agreement, the term “Purchaser” includes any
person substituted for a Purchaser under this Section. Nothing herein will
relieve a defaulting Purchaser from liability for its default.

 

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10. Survival of Certain Representations and Obligations. The respective
indemnities, agreements, representations, warranties and other statements of the
Company or its officers and of the several Purchasers set forth in or made
pursuant to this Agreement will remain in full force and effect, regardless of
any investigation, or statement as to the results thereof, made by or on behalf
of any Purchaser, the Company or any of their respective representatives,
officers or directors or any controlling person, and will survive delivery of
and payment for the Offered Securities. If this Agreement is terminated pursuant
to Section 9 or if for any reason the purchase of the Offered Securities by the
Purchasers is not consummated, the Company shall remain responsible for the
expenses to be paid or reimbursed by it pursuant to Section 5 and the respective
obligations of the Company and the Purchasers pursuant to Section 8 shall remain
in effect and if any Offered Securities have been purchased hereunder the
representations and warranties in Section 2 and all obligations under Section 5
shall also remain in effect. If the purchase of the Offered Securities by the
Purchasers is not consummated for any reason other than solely because of the
termination of this Agreement pursuant to Section 9 or the occurrence of any
event specified in clause (iii), (iv), (vi), (vii) or (viii) of Section 7(c),
the Company will reimburse the Purchasers for all out-of-pocket expenses
(including fees and disbursements of counsel) reasonably incurred by it in
connection with the offering of the Offered Securities.

11. Notices. All communications hereunder will be in writing and, if sent to the
Purchasers will be mailed, delivered or telegraphed and confirmed to the
Purchasers at Credit Suisse Securities (USA) LLC, Eleven Madison Avenue,
New York, NY 10010-3629, Attention: LCD-IBD, and J.P.Morgan Securities Inc. 383
Madison Avenue, New York, NY 10179 or, if sent to the Company, will be mailed,
delivered or telegraphed and confirmed to it at 4600 Post Oak Place, Suite 200,
Houston, Texas 77027, Attention: John Tschirhart, with a copy to Jackson Walker
L.L.P., 1401 McKinney St., Suite 1900, Houston, Texas 77010, Attention: Richard
Roth.

12. Successors. This Agreement will inure to the benefit of and be binding upon
the parties hereto and their respective successors and the controlling persons
referred to in Section 8, and no other person will have any right or obligation
hereunder, except that holders of Offered Securities shall be entitled to
enforce the agreements for their benefit contained in the second and third
sentences of Section 5(b) hereof against the Company as if such holders were
parties thereto.

13. Counterparts. This Agreement may be executed in any number of counterparts,
each of which shall be deemed to be an original, but all such counterparts shall
together constitute one and the same Agreement.

14. Absence of Fiduciary Relationship. The Company acknowledges and agrees that:

(a) No Other Relationship. The Purchasers have been retained solely to act as
initial purchasers in connection with the initial purchase, offering and resale
of the Offered Securities and that no fiduciary, advisory or agency relationship
between the Company and any of the Purchasers has been created in respect of any
of the transactions contemplated by this Agreement or the Preliminary or Final
Offering Circular, irrespective of whether any Purchaser has advised or is
advising the Company on other matters;

(b) Arm’s-Length Negotiations. The purchase price of the Offered Securities set
forth in this Agreement was established by the Company following discussions and
arms-length negotiations with the Purchasers and the Company is capable of
evaluating and understanding and understands and accepts the terms, risks and
conditions of the transactions contemplated by this Agreement;

(c) Absence of Obligation to Disclose. The Company has been advised that each of
the Purchasers and its affiliates are engaged in a broad range of transactions
which may involve interests that differ from those of the Company and that none
of the Purchasers has any obligation to disclose such interests and transactions
to Company by virtue of any fiduciary, advisory or agency relationship; and

 

22

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(d) Waiver. The Company waives, to the fullest extent permitted by law, any
claims it may have against each of the Purchasers for breach of fiduciary duty
or alleged breach of fiduciary duty and agrees that none of the Purchasers shall
have any liability (whether direct or indirect) to the Company in respect of
such a fiduciary duty claim or to any person asserting a fiduciary duty claim on
behalf of or in right of the Company, including shareholders, employees or
creditors of the Company.

15. Applicable Law. This Agreement shall be governed by, and construed in
accordance with, the laws of the State of New York.

The Company hereby submits to the non-exclusive jurisdiction of the Federal and
state courts in the Borough of Manhattan in The City of New York in any suit or
proceeding arising out of or relating to this Agreement or the transactions
contemplated hereby. The Company irrevocably and unconditionally waives any
objection to the laying of venue of any suit or proceeding arising out of or
relating to this Agreement or the transactions contemplated hereby in Federal
and state courts in the Borough of Manhattan in The City of New York and
irrevocably and unconditionally waives and agrees not to plead or claim in any
such court that any such suit or proceeding in any such court has been brought
in an inconvenient forum.

 

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If the foregoing is in accordance with the Purchasers’ understanding of our
agreement, kindly sign and return to us one of the counterparts hereof,
whereupon it will become a binding agreement between the Company and the several
Purchasers in accordance with its terms.

 

Very truly yours, ATP Oil & Gas Corporation By:  

/s/ Leland E. Tate

Name:   Leland E. Tate Title:   President

--------------------------------------------------------------------------------

The foregoing Purchase Agreement is hereby confirmed and accepted as of the date
first above written. CREDIT SUISSE SECURITIES (USA) LLC For itself and on behalf
of the several Underwriters listed in Schedule 1 hereto. By:  

/s/ Timothy E. Perry

 

Authorized Signatory

Managing Director

J.P. MORGAN SECURITIES INC. For itself and on behalf of the several Underwriters
listed in Schedule 1 hereto. By:  

/s/ Michael O’Donovan

  Authorized Signatory   Managing Director CANACCORD ADAMS INC. By:  

/s/ Christian B. Gibson

  Authorized Signatory PRITCHARD CAPITAL PARTNERS, LLC. By:  

/s/ Todd Giustiniano

  Authorized Signatory SMH CAPITAL, INC. By:  

/s/ William W. Sprague

  Authorized Signatory

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SCHEDULE A

 

Purchaser

   Shares of
Firm Securities    Shares of
Optional Securities

Credit Suisse Securities (USA) LLC

   531,250    148,750

J.P.Morgan Securities Inc.

   531,250    148,750

Canaccord Adams Inc.

   62,500    17,500

Pritchard Capital Partners, LLC

   62,500    17,500

SMH Capital, Inc.

   62,500    17,500          

Total

   1,250,000    350,000          

 

A-1

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SCHEDULE B

 

1. Issuer Free Writing Communications (included in the General Disclosure
Package)

Final term sheet, dated September 23, 2009, a copy of which is attached hereto.

 

2. Other Information Included in the General Disclosure Package

The following information is also included in the General Disclosure Package:

None.

 

B-1

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SCHEDULE C

Supplemental Marketing Materials

None.

 

C-1

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SCHEDULE D

The Purchaser shall have received letters (A) on the date hereof, from
PricewaterhouseCoopers LLP and Deloitte & Touche LLP, dated the date hereof, and
(B) on each Closing Date, from PricewaterhouseCoopers LLP, dated as of such
Closing date, in each case confirming that they are a registered public
accounting firm and independent public accountants within the meaning of the
Securities Laws to the effect that:

(i) in their opinion the audited consolidated financial statements and schedules
examined by them and included in the Preliminary and Final Offering Circular and
in the Exchange Act Reports comply as to form in all material respects with the
applicable accounting requirements of the Securities Laws;

(ii) with respect to the period(s) covered by the unaudited quarterly
consolidated financial statements included in the Preliminary and Final Offering
Circular or in the Exchange Act Reports, they have performed the procedures
specified by the American Institute of Certified Public Accountants for a review
of interim financial information as described in AU 722, Interim Financial
Information, on the unaudited quarterly consolidated financial statements
(including the noted thereto) of the Company and its consolidated subsidiaries
included in the Preliminary and Final Offering Circular or in the Exchange Act
Reports, and have made inquiries of certain officials of the Company who have
responsibility for financial and accounting matters of the Company and its
consolidated subsidiaries as to whether such unaudited quarterly consolidated
financial statements comply as to form in all material respects with the
applicable accounting requirements of the Securities Act and the related
published rules and regulations; they have read the latest unaudited monthly
consolidated financial statements (including the notes thereto) and the
supplementary summary unaudited financial information of the Company and its
consolidated subsidiaries made available by the Company and the minutes of the
meetings of the shareholders, Board of Directors and committees of the Board of
Directors of the Company; and have made inquiries of certain officials of the
Company who have responsibility for financial and accounting matters of the
Company and its consolidated subsidiaries as to whether the unaudited monthly
financial statements are stated on a basis substantially consistent with that of
the audited consolidated financial statements included in the Preliminary and
Final Offering Circular and the Exchange Act Reports; and on the basis thereof,
nothing came to their attention which caused them to believe that:

(A) the unaudited financial statements included in the Preliminary and Final
Offering Circular or in the Exchange Act Reports do not comply as to form in all
material respects with the applicable accounting requirements of the Securities
Laws, or that any material modifications should be made to the unaudited
quarterly consolidated financial statements for them to be in conformity with
generally accepted accounting principles;

(B) with respect to the period subsequent to the date of the most recent
unaudited quarterly consolidated financial statements included in the
Preliminary and Final Offering Circular or in the Exchange Act Reports, at a
specified date at the end of the most recent month, there were any increases in
the short-term debt or long-term debt of the Company and its consolidated
subsidiaries, or any change in the consolidated capital stock of the Company and
its consolidated subsidiaries as compared with the amounts shown on the latest
balance sheet included in the Exchange Act Reports except for such changes or
increases set forth in such letter which the Exchange Act Reports disclose have
occurred or may occur;

(iii) With respect to any period as to which officials of the Company have
advised that no consolidated financial statements as of any date or for any
period subsequent to the specified date referred to in (ii)(B) above are
available, they have made inquiries of certain officials of the Company who have
responsibility for the financial and accounting matters of the Company and its

 

D-1

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consolidated subsidiaries as to whether, at a specified date not more than three
business days prior to the date of such letter, there were any increases in the
short-term debt or long-term debt of the Company and its consolidated
subsidiaries, or any change in the consolidated capital stock of the Company and
its consolidated subsidiaries as compared with the amounts shown on the most
recent balance sheet for such entities included in the Exchange Act Reports and,
on the basis of such inquiries and the review of the minutes described in
paragraph (ii) above, nothing came to their attention which caused them to
believe that there was any such change or increase except for such changes or
increases set forth in such letter which the Exchange Act Reports disclose have
occurred or may occur; and

(iv) they have compared specified dollar amounts (or percentages derived from
such dollar amounts) and other financial and statistical information contained
in the Preliminary Offering Circular, each other document comprising any part of
the General Disclosure Package, the Final Offering Circular and each item of
Supplemental Marketing Material (other than any Supplemental Marketing Material
that is an electronic road show and the Exchange Act Reports (in each case to
the extent that such dollar amounts, percentages and other financial and
statistical information are derived from the general accounting records of the
Company and its subsidiaries or are derived directly from such records by
analysis or computation) with the results obtained from inquiries, a reading of
such general accounting records and other procedures specified in such letter
and have found such dollar amounts, percentages and other financial and
statistical information to be in agreement with such results.

 

D-2

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EXHIBIT A

FORM OF

ATP OIL & GAS CORPORATION

CHIEF FINANCIAL OFFICER’S CERTIFICATE

I, Albert L. Reese Jr., do hereby certify that I am the Chief Financial Officer
of ATP Oil & Gas Corporation, a Texas corporation (the “Company”), and, in my
capacity as Chief Financial Officer, and based upon an examination of the
Company’s financial records and schedules undertaken by myself or members of my
staff who are responsible for the Company’s financial and accounting matters, do
hereby certify that:

 

  1. I am providing this certificate in connection with the marketing of [    ]
shares of the Company’s [    ]% convertible perpetual preferred stock, as
described in that certain offering circular, dated September [    ], 2009 (the
“Offering Circular”);

 

  2. I am familiar with the accounting, operations and records systems of the
Company;

 

  3. I have read the (1) the Offering Circular, (2) the Annual Report on Form
10-K for the year ended December 31, 2008, (3) the Quarterly Report on Form 10-Q
for the quarter ended March 31, 2009 and (4) The Quarterly Report on Form 10-Q
for the quarter ended June 30, 2009.

 

  4. No consolidated financial statements of the Company as of any date for any
period subsequent to [    ] , 2009 are currently available;

 

  5. I have no reason to believe that for the period from [    ] 2009 to [    ]
2009, there were any decreases, as compared with the corresponding period in the
preceding year, in consolidated net sales or in the total or per-share amounts
of income before extraordinary items or of net income, except in all instances
for changes, increases or decreases that the Offering Circular discloses have
occurred or may occur;

 

  6. I have supervised the compilation of and reviewed the circled information
contained on the attached Exhibit A, which is included or incorporated by
reference into the Offering Circular. I have performed the following procedures
with respect to the circled information identified on Exhibit A, which were
applied as indicated with respect to the capital letters as explained below,
and, to my knowledge, such information is correct, complete and accurate in all
material respects:

 

  a. Recomputed and/or compared to corresponding amounts appearing in the
accounting records of the Company and found the amounts (as adjusted for
rounding, where appropriate) to be in agreement.

 

  b. Compared and agreed (as adjusted for rounding, where appropriate), or
recalculated and agreed (as adjusted for rounding, where appropriate), to a
schedule derived from the Company’s accounting records, and compared the amounts
on the schedule to corresponding amounts appearing in the accounting records and
found the amounts to be in agreement (as adjusted for rounding, where
appropriate) and determined that the amounts on the schedule were arithmetically
correct.

 

  c. Proved the arithmetic accuracy of the percentages and ratios (as adjusted
for rounding, where applicable) based on data in the above-mentioned accounting
records and schedules.

 

Ex. A-1

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In witness whereof this certificate has been executed and delivered by the chief
financial officer of the Company on this      day of September, 2009.

 

 

Albert L. Reese, Jr. Chief Financial Officer

 

Ex. A-2