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                                                                     EXHIBIT 4.5

                           SUPPLEMENTARY AGREEMENT TO
                  COMPREHENSIVE PRODUCTS AND SERVICES AGREEMENT

      This Supplementary Agreement to Comprehensive Products and Services
Agreement (this "Supplementary Agreement") is executed this 9th day of June,
2005 in Beijing by and between the following two parties through their
respective authorized representatives:

      (1) China National Petroleum Corporation ("CNPC"), a state-owned
enterprise duly established and existing under the laws of the People's Republic
of China (the "PRC"), with its enterprise legal person business license number
being 1000001001043 and registered address being at Liupukang, Xicheng District,
Beijing; and

      (2) PetroChina Co., Ltd. ("PetroChina"), a joint stock limited company
duly established and existing under the laws of the PRC, with its enterprise
legal person business license number being 1000001003252 and registered address
being at 16 Andelu, Dongcheng District, Beijing.

      WHEREAS,

      1. PetroChina is a company incorporated under the laws of the PRC and its
H shares and the American Depositary Shares are currently listed and traded on
the Stock Exchange of Hong Kong Limited and on the New York Stock Exchange, Inc.
respectively. PetroChina shall, therefore, comply with the laws of the PRC and
of the jurisdictions in which its shares are listed in the conduct of its
operations and other business activities.

      2(pound)(R)CNPC and PetroChina executed the Comprehensive Products and
Services Agreement dated March 10, 2000 (the "Master Agreement"), whereby, CNPC
and PetroChina shall, and shall agree to cause their respective subsidiaries,
branches and other controlled entities to, provide relevant products and
services to each other pursuant to relevant provisions therein.

      3. PetroChina intends to increase registered capital of Zhong You Kan Tan
Kai Fa Co., Ltd. (the "Zhong You Kan Tan"), indirectly 100% owned subsidiary of
CNPC, so as to acquire 50% of the equity interest in Zhong You Kan Tan. For the
purpose thereof, PetroChina and CNPC have agreed to make amendments to the
Master Agreement, which shall constitute a supplementary agreement thereto.

      4. Both parties hereby agree to, and warrant that they will cause their
respective subsidiaries, branches and any other controlled entities to, provide
relevant products and services to each other both within and outside of the PRC
pursuant to the terms and principles set forth in the Master Agreement and this
Supplementary Agreement.

Now, therefore, the parties hereto reach agreement as follows:

                                       -1-
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                                    ARTICLE 1

      CNPC and PetroChina agree that the Master Agreement shall be amended as
follows:

      1. "Government-Set-Price" shall mean the price for such type of services
as determined in any laws, regulations, decisions, orders or guidelines enacted
by any government of the relevant country/region (including but not limited to
any central government, federal government, local government, state/league
government, and any other instrumentality that rules a certain territory by
controlling domestic issues and foreign affairs thereof, in whatever name,
structure and form), and any other regulatory authority.

      2. "Market Price" shall mean the price determined according to the
following order of priority:

      (i)   the price then charged by independent third parties providing such
            type of services at arm's length in the region where such type of
            services is provided; or

      (ii)  the price then charged by independent third parties providing such
            type of services at arm's length in the regions/ countries near the
            region where such type of services is provided.

      3. This Supplementary Agreement shall be effective for a term of three (3)
years, commencing from the date on which this Supplementary Agreement comes into
effect. The Master Agreement shall remain effective during the term hereof and
shall expire simultaneously with the expiration of the Supplementary Agreement.

                                    ARTICLE 2

      This Supplementary Agreement shall constitute amendments and supplements
to the Master Agreement. Any matters not covered hereunder shall be governed by
the Master Agreement. In case of any discrepancy between this Supplementary
Agreement and the Master Agreement, this Supplementary Agreement shall prevail.

                                    ARTICLE 3

      This Supplementary Agreement shall come into effect after being executed
by the authorized representatives of both parties hereto and approved by the
shareholders' general meeting of PetroChina and PetroChina having become the
shareholder of Zhong You Kan Tan.

                                    ARTICLE 4

      IN WITNESS WHEREOF, both parties have caused this Supplementary Agreement
to be executed at the date written on the first page above.

                                       -2-
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CHINA NATIONAL PETROLEUM CORPORATION (company seal)

By: /s/ Zhou Jiping
    ----------------------------

PETROCHINA CO., LTD. (Company)

By: /s/ Wang Guoliang
    ----------------------------

                                       -3-<PAGE>

                                                                    EXHIBIT 10.1

            SIGNIFICANT DIFFERENCES IN CORPORATE GOVERNANCE PRACTICES
                       FOR PURPOSES OF SECTION 303A. 11 OF
                THE NEW YORK STOCK EXCHANGE LISTED COMPANY MANUAL

      On November 4, 2003, the New York Stock Exchange (the "NYSE") adopted new
corporate governance rules. Under these rules, we are required to disclose a
summary of the significant differences between our corporate governance
practices and those that would apply to a U.S. domestic issuer under the NYSE
corporate governance rules.

      We are incorporated under the laws of the People's Republic of China (the
"PRC"), with H shares publicly traded on the Hong Kong Stock Exchange (the
"HKSE") and American Deposit Shares representing H shares on the NYSE. As a
result, our corporate governance framework is subject to the mandatory
provisions of the PRC Company Law and the securities laws and regulations of
Hong Kong and the United States.

      The following discussion summarizes the significant differences between
our corporate governance practices and those that would apply to a U.S. domestic
issuer under the NYSE corporate governance rules.

BOARD INDEPENDENCE

      Under the NYSE corporate governance rule 303A.01, a listed company must
have a majority of independent directors on its board of directors. A company of
which more than 50% of the voting power is held by an individual, a group or
another company (a "controlled company") is not required to comply with this
requirement. Because approximately 90% of our voting power is controlled by
China National Petroleum Corporation ("CNPC"), we, as a controlled company,
would not be required to comply with the majority of independent directors
requirement. In addition, we are not required under the PRC Company Law and the
Rules Governing the Listing of Securities on the Stock Exchange Hong Kong
Limited (the "HKSE Listing Rules") to have a majority of independent directors
on our board of directors. Currently, three of our thirteen directors are
independent non-executive directors.

      Under the NYSE corporate governance rule 303A.03, the non-executive
directors of a listed company must meet at regularly scheduled executive
sessions without management. There are no mandatory requirements under the PRC
Company Law and the HKSE Listing Rules that a listed company should hold, and we
currently do not hold, such executive sessions.

NOMINATING/CORPORATE GOVERNANCE COMMITTEE

      Under the NYSE corporate governance rule 303A.04, a listed company must
have a nominating/corporate governance committee composed entirely of
independent directors, with a written charter that covers certain minimum
specified duties. We are not required under the PRC Company Law and the HKSE
Listing Rules to have, and we do not currently have, a nominating/corporate
governance committee.

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COMPENSATION COMMITTEE

      Under the NYSE corporate governance rule 303A.05, a listed company must
have a compensation committee composed entirely of independent directors, with a
written charter that covers certain minimum specified duties. The compensation
committee of a "controlled company" is not required to be composed entirely of
independent directors. We are not required under the PRC Company Law to have a
compensation committee. Under the Corporate Governance Code of the HKSE Listing
Rules, a listed company must have a remuneration committee composed of a
majority of independent non-executive directors, with a written terms of
references that covers certain minimum specified duties.

      We currently do not have a compensation committee composed entirely of
independent directors. However, we have an evaluation and remuneration committee
including independent non-executive directors. The major responsibilities of our
evaluation and remuneration committee include:

   -  reviewing the current standing of President-appointed Senior Vice
      President, Vice Presidents, Chief Financial Officer and other senior
      management personnel and making recommendations for such review to the
      board of directors;

   -  managing and conducting performance evaluations for our President and
      reporting the results of such evaluations to the board of directors;

   -  monitoring performance evaluations conducted by our President for Senior
      Vice President, Vice Presidents, Chief Financial Officer and other senior
      management personnel; and

   -  studying our incentive plan, compensation plan and stock appreciation
      rights plan, supervising and evaluating the implementation of these plans
      and making recommendations for further improvements to such plans.

CORPORATE GOVERNANCE GUIDELINES

      Under the NYSE corporate governance rule 303A.09, a listed company must
adopt and disclose corporate governance guidelines that cover certain minimum
specified subjects. We are not required under the PRC Company Law and the HKSE
Listing Rules to have, and we do not currently have, formal corporate governance
guidelines. However, we have the Articles of Association, a Manual of Board of
Directors and a Trial Implementation Rules for Compensation of Senior Management
that address the following subjects:

   -  director qualification standards and responsibilities;

   -  key board committee responsibilities;

   -  director compensation; and

   -  director orientation and continuing education

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      In addition, under the HKSE Listing Rules, we are expected to comply with,
but may choose to deviate from, certain code provisions in the Corporate
Governance Code of the Listing Rules which sets forth the principles and
standards of corporate governance for listed companies. Pursuant to the HKSE
Listing Rules, if we choose to deviate from any code provisions of the Corporate
Governance Code, we must disclose such deviations in our annual report.

CODE OF BUSINESS CONDUCT AND ETHICS

      Under the NYSE corporate governance rule 303A.10, a listed company must
adopt and disclose its code of business conduct and ethics for directors,
officers and employees. We adopted our code of business conduct and ethics for
senior management on March 23, 2004 and have disclosed the content of this code
on our website and in the annual report on Form 20-F for the fiscal year ended
December 31, 2003. In addition, we adopted our code of business conduct and
ethics for employees on March 2, 2005 and have disclosed the content of this
code on our website. We are not required under the PRC Company Law and the HKSE
Listing Rules to have, and we do not currently have, a code of business conduct
and ethics for directors. However, pursuant to the HKSE Listing Rules, all of
our directors must comply with the Model Code for Securities Transactions by
Directors of Listed Companies (the "Model Code") as set out in the Listing
Rules. The Model Code sets forth required standards with which the directors of
a listed company must comply in securities transactions of the listed company.

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