Exhibit 2.16



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LOAN AGREEMENT



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Between:



PETROBRAS ENERGIA S.A.



And



PETROBRAS
INTERNATIONAL BRASPETRO BV. - PIB-BV





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LOAN AGREEMENT NUMBER: 0088/2005



The undersigned:



1 PETROBRAS ENERGIA S.A., a company incorporated and existing under the laws of ARGENTINA, with registered office at Maipu 1, Piso 22o - Ciudad
Autónoma de, Buenos Aires, ARGENTINA, BUENOS AIRES, hereinafter referred to as: Borrower



and



2 PETROBRAS INTERNATIONAL BRASPETRO
BV., a company incorporated and existing under the laws of NETHERLANDS, having its registered office in, Rokin, 55, 1012 kk, THE NETHERLANDS, P.O.Box 990 - 1000 AZ, AMSTERDAM hereinafter referred to as : Lender



Lender and Borrower hereinafter jointly referred to as: Parties and individually
also as: Party,



Whereas :



(a)Parties are part of the international group of companies of Petroleo Brasileiro
S.A. (PETROBRAS);



(b)PETROBRAS is a global leader in the
oil, gas, and energy industry;



(c)In view of further expansion of the
business activities of PETROBRAS, It has been agreed between the Parties that Lender lends to Borrower an amount of USD 200,000,000.00 (United States Dollars Two Hundred Million) (the Loan);



(d)Parties now wish to enter into this agreement for the purpose of formalizing and
setting out the terms and conditions of the Loan ( the Agreement).



Have agreed as follows:



Article 1 - Loan



1.1On the terms and subject to the conditions set out herein, Lender has agreed
to lend the Loan to Borrower and Borrower has agreed to borrow the Loan from Lender.



1.2The Loan will be made available to Borrower on February 22, 2005 in its account at CITIBANK N.A., ACCOUNT # 36968355, ABA 021000089, BENEFICIARY: PETROBRAS ENERGIA S.A..





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Article 2 - Interest



2.1The Loan shall bear per annum interest at the rate of 7,22%, net of withholding taxes. The interest is calculated on the basis of a 360 days year, consisting
of 12 equal months of 30 days each.



2.2The interest shall be due and
payable on February 22 and August 22 of each year, until the final maturity, starting on August 22, 2005. If any such payment date falls in a day other than a business day, the payment will be made in the following business day.



Article 3 - Administrative Expenses



3.1 The Borrower agrees to pay to the Lender, on the closing date the amount of US$
1,500,000 (one million five hundred thousand United States Dollars) (the Fee) as Administrative Expenses.



3.2 The Fee shall be discounted from the Loan proceedings US$ 200,000,000 (two hundred million United States Dollars) on the closing date by the Lender. Once paid,
the Fee shall not be refundable under any circumstances



Article 4 - Term
and Accelerated Repayment



4.1Term. The Loan shall be repaid in
full on February 22, 2015, without prejudice to article 4.2.



4.2Accelerated repayment. The Loan shall be repaid in full together with all accrued interest and any other amounts due under the Agreement at the day of termination of the Agreement in accordance with article 6 of the Agreement.



Article 5 - Payments



5.1Payments made by Borrower to Lender shall be made into the account of Lender.



5.2All payments by Borrower, whether on the Loan or interest, shall be made in United
States Dollars ($).



Article 6 - Pre Payment



6.1The Loan could be prepaid without penalty or charge at any moment. The interest
will be calculated on pro rata rate.





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Article 7 - Termination



7.1Either Party shall have the right to terminate the Agreement with immediate effect if and when the other Party is in default. A Party shall only be in
default following receipt of a written notice from the other Party in this respect expressing which obligation(s) has (have) not been performed and requesting that the default be remedied, and the Party in default has not remedied its default within
a period of 30 days after the date of such notice.



7.1.1In case the
Borrower doesnt pay to the Lender, in the date of expiration, the Loan, increased with the interest as referred in the item 2.1, the Borrower will be automatically in default, and the amount to be paid will also be increased with a 2% (two
percent) fine.



7.1.2In case the payment referred in the item 7.1.1 is
made up to five days after the expiration date, the above referred fine will not be applied.



7.2Parties may also decide to terminate the Agreement by mutual agreement.



7.3In addition to its right to terminate the Agreement in accordance with article 6.1 above, Lender shall have the right to terminate the Agreement with immediate
effect in case:



a petition for a moratorium has been filed by Borrower with
respect to Borrower or a moratorium is imposed upon Borrower;



a petition for
bankruptcy has been filed with respect to Borrower or Borrower is declared bankrupt;



a resolution to dissolve the Borrower has been made;



a receiver has
been appointed with respect of Borrower;



Borrower is placed under
guardianship; or



Borrower is no longer part of the international group of
companies of PETROBRAS due to a divestiture of PETROBRAS from the controlling party of the Borrower.



Article 8 - Notices



8.1Any
notice or other communication under or in connection with the Agreement shall be in writing in the English language and shall be delivered by registered mail or facsimile to the respective addresses or fax numbers as set out in article 8.2 or any
new address or fax number as a Party may have notified the other Party in accordance with this article 8.





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8.2Any notice or communication to Lender and Borrower shall be sent to the following address:



Borrower:

PETROBRAS ENERGIA S.A. - Maipú 1, Piso 22o - Ciudad Autónoma de,

Buenos Aires, ARGENTINA, BUENOS AIRES

Att: Michael Ditchfield



Lender:

PETROBRAS INTERNATIONAL BRASPETRO BV. - PIB-BV

Rokin, 55, 1012 kk, THE NETHERLANDS, P.O.Box 990 - 1000 AZ, AMSTERDAM

Att:
Daniel Lima de Oliveira



Any notice or communication from any parties should be
copied to Petrobras to the following address:



Petrobras:

Petróleo Brasileiro S.A  PETROBRAS

Av. República do
Chile 65/ 302

20031-912

Rio de Janeiro, RJ - Brazil

Att: Daniel Lima de Oliveira



Article 9 - Waiver



Any forbearance or delay on the part of any Party enforcing any provision of the Agreement or any of its rights hereunder shall no be constructed as a waiver of such provisions or of a right thereafter to enforce the
same.



Article 10 - Invalidity



In the event any provision in the Agreement is void, invalid or in any way not enforceable,
the validity and enforceability of the remaining provisions shall not in any way be affected. The provision concerned will be converted by operation of law into a legally valid arrangement as similar in content and effect to the invalid provision as
possible, unless and until the Parties themselves by mutual consent replace the provision concerned with a legally valid alternative arrangement.





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Article 11 - Assignment and transfer



Parties may only assign or transfer, in whole or in part, any of their rights or obligations hereunder by mutual and prior agreement.



Article 12 - Amendments



No variation or amendment of the Agreement shall be valid and binding unless agreed to in
writing by Parties.



Article 13 - Governing law and Competent court



13.1Governing law. The Agreement shall be construed in accordance
with and shall in all respects be governed by the laws of the Netherlands.



13.2Arbitration. Any dispute or difference arising in connection with the Agreement that cannot be amicably settled between the Parties shall be finally settled by arbitration in accordance with the rules of Arbitration of The
Netherlands Arbitration Institute (N.A.I.). Unless Parties agree otherwise, one arbiter will suffice. The language of such arbitration shall be English. The place of arbitration shall be in Rotterdam, The Netherlands.



Thus agreed and signed in two fold in Rio de Janeiro, Brazil on February 21, 2005.



Michael DitchfieldPETROBRAS ENERGIA S.A.Financial Manager




Daniel Lima de OliveiraPETROBRAS INTERNATIONAL BRASPETRO BV. -PIB-BVDirector