-----------------------PUBLIC TRANSLATION OF EXTENSION AGREEMENT---------------------

MEMORANDUM OF AGREEMENT------------------------------------------------------------------------

On June 11, 2009 in the city of Neuquén, a meeting is held between, on behalf of the Province of Neuquén, the members of the Renegotiation Technical Commission set up by Executive Order number 822/2008 and Resolution of the State Secretariat of Natural Resources number 104/08, Mr. Héctor Mendiberri, Mr. Juan Carlos Nayar, Mr. Alex Valdez, Mr. José Gabriel López and Mr.  Ricardo Dardo Esquivel domiciled at Rioja 229 of the city of Neuquén (hereinafter the “PROVINCE”), one party, and Petrolera Entre Lomas S.A. (hereinafter “ PELSA”), herein represented by Oscar  Aníbal Vicente and José Pantano,  domiciled at Bouchard 680, 18 th Floor, City of Buenos Aires, Petrobras Energia S.A., herein represented by Mr. Marcelo Daniel Sampataro, domiciled at Maipú 1, 22 nd . Floor, City of Buenos Aires, and APCO Argentina, herein represented by Mr. Mr. Ernesto Alejandro Hermo, domiciled at Libertador 498, 26 th Floor , City of Buenos Aires (hereinafter all of them jointly referred to as the “COMPANIES” and individually as “COMPANY”), the other party, and both jointly referred to as the "PARTIES", and ------------ WHEREAS: -------------------------------------------------------------------------------------------------------

On May 23, 2008, the Executive Power of the PROVINCE issued the Executive Order number 822/08 by means of which the State Secretariat of Natural Resources was authorized by the National Government to call for public bids of companies licensed to exploit hydrocarbon areas which were interested in their registration in the Provincial Registry of Renegotiation of Concessions of Hydrocarbon Areas, under the applicable national and provincial law in effect, approving the Fundamental Terms and Conditions of said public call for bids pursuant to National Laws number 17319, 23696, 24145 and 26197, National Executive Orders number 1055/89, 1212/89, 1589/89, 1285/92, 1287/92, 1291/94 and 1008/94, and Administrative Decision of the Chief of the Cabinet of Ministers of the National Executive Power number 407/97, and all other applicable national and provincial laws.

On the other hand, the PROVINCE, pursuant to the applicable hydrocarbon laws in effect, in addition to the administration of the areas and concessions, is extending the concession terms for the exploitation of the national concessions referred to, with the purpose hereinafter stated, and essentially with the purpose of obtaining better income on the gas and oil production within its sovereignty, increasing the reserves and the production as well as improving the investments in exploration, all of this under Acts number 17319, 24145, 23696 (and norms derived from the latter),  and Act 26197, whose section 6 sets forth: “As from the enactment of this law, the Provinces, as Application Authority, shall exercise the functions of counterpart of the exploration permits, hydrocarbon exploitation and transportation concessions, having authority, among others, to: (I) exercise fully and independently the activities related to the control and supervision of the above mentioned permits and concessions, and of any other kind of hydrocarbon exploration and/or exploitation contract executed or approved by the National Government; (II) demand the fulfillment of the legal and/or contractual obligations applicable with reference to investments, rational exploitation of resources, information, and payment of concession fees and royalties; (III) order the extension of legal and/or contractual terms; and (IV) apply the sanction system set forth in Act number 17319 and its regulation

(sanctions consisting in fines, suspension of the registration, lapsing of rights and any other sanction provided for in the specifications of the fundamental terms and conditions or in the contracts).” -------

The powers described in the previous paragraph do not limit the rest of the powers derived from the granting authority arising out of Act number 17319 and its regulation. ----------------

On August 5, 2008,  the COMPANIES submitted to the PROVINCE a notice by means of which they applied for the registration in the Provincial Registry of Negotiation of extension of Exploitation Concessions stated in SECTION 1 herein; they attached to said notice the documentation and information provided for in section 4.1 of Executive Order number 822/2008. On March 20, 2009 the PROVINCE communicated to PELSA, in its capacity of operator of said Concessions, the beginning of the negotiation period. As a consequence of said process, it is the intention of the PARTIES to subscribe this MEMORANDUM OF AGREEMENT which shall be subject to the following terms and conditions, pursuant to the powers granted by Provincial Law number 2615. ------------------------------------------------------

THEREFORE THE PARTIES AGREE

The PARTIES agree, pursuant to National Laws 17319, 23696, 24145 and 26197, Provincial Law 2615, National Executive Orders 1055/89, 1212/89, 1589/89, 1285/92, 1287/92, 1291/94, and 1008/94, Administrative Decision of the Chief of the Cabinet of Ministers of the National Executive Power 407/97, and national and provincial laws applicable to the matter, to carry out the renegotiation provided for in Executive Order 822/08 and, consequently, extend the original term of the Exploitation Concessions whose oil fields are located in the territory administered by the PROVINCE which are detailed hereinafter, under the provisions of section 35 of Act 17319, for the term of ten years as provided for “infra”. ----------------------------------------------------------------------------------------------

1. Entre Lomas, granted by Executive Order number 87/91 and Deed Granting Formal Title to the Concession number 64 of the Argentine’s Office of the General Notary dated February 24, 1997, the current Concession Holder being PELSA, with maturity date on January 21, 2016 and extended up to January 21, 2026.   2. Bajada del Palo, granted by Executive Orders number 1769/90 and 263/92, the current Concession Holders being,

pursuant to file number 3450-2068/07 of the State Secretariat of Energy and Mining of the Province of Neuquén,  PELSA  (73,15%), APCO Argentina Inc. Argentine Branch (23%)  and Petrobras Energía S.A. (3,85%), with maturity date on September 06, 2015 and extended up to September 06, 2025.

SECTION 2 :REPRESENTATIONS AND GUARANTEES

The COMPANIES hereby irrevocably represent and guarantee to the PROVINCE that: 1. They shall carry out exploration tasks in the areas of remaining exploration that may exist, corresponding to the licensed areas they own as mentioned in SECTION 1 and the integral assessment of all its reservoirs, with the purpose of tending to increase the reserves, which shall allow an adequate level of production and horizon of said reserves on the basis of the technical-economic viability of the reservoirs. Moreover, in order to exploit their oil fields they shall use the best technology available, by means of a permanent and sustained investment, which shall allow maximizing the extraction of these resources, under conditions of adequate economic profitability, and financial viability, carrying out good practices for the exploitation of the different reservoirs and keeping the necessary care, remedy and protection of the environment.   2. The unified denomination of COMPANIES exists to the end of expressing that each COMPANY undertakes the rights and duties herein provided for exclusively to the extent of their specific participation in the area covered by the exploitation concession they own.   3. Taking into account that PELSA sells its crude oil production almost entirely to its majority shareholder Petrobras Energía SA, for the purposes of calculating the Extraordinary Income, PELSA shall be considered a company incorporated under the provisions of Act 2615. ------------------------------------------The PROVINCE hereby irrevocably represents and guarantees to the COMPANIES that: 1. The COMPANIES shall have the peaceful use and enjoyment of the exploitation and transportation concessions they own, for the whole term of the concession and its

extension period, and the PROVINCE shall keep the COMPANIES indemnified in case of any claim or action or decision or legislative change that might affect or modify the ownership system that applies to the areas of the concessions within the jurisdiction of the Province of Neuquén, undertaking the obligation to maintain the COMPANIES in full exercise of their rights with relation to said concessions. The PROVINCE has full powers to enter into this Memorandum of Agreement and comply with its obligations hereunder. 2. The execution and fulfillment of this Memorandum of Agreement on the part of the PROVINCE does not breach nor infringe any disposition of any applicable norm whatsoever (notwithstanding the type of norm it may be, including but not limited to federal, provincial and municipal norms), as well as any resolution, decision or judgment of any national or provincial governmental and/or judicial authority. In particular, the PROVINCE represents and guarantees that the extension of the concessions is subject to Acts 17319 and 26197 and that sections 95, 96 and 100 of the Constitution of the Province of Neuquén shall not apply, all this pursuant to the normative prevalence provided for in section 31 of the National Constitution. 3. There is no action, lawsuit, claim, complaint, audit, arbitration, investigation or proceeding (either civil, criminal, administrative, preliminary criminal proceeding or of another kind) which may prevent the PROVINCE from subscribing this Memorandum of Agreement. -----------------------------------------------------

SECTION 3 :NEGOTIATION CONDITIONS OF TERM EXTENSIONS

The PARTIES, with reference to the extension of the exploitation concessions mentioned in SECTION 1 hereof, agree as follows: 3.1 INITIAL PAYMENT: PELSA, as operator of the Concessions and acting on behalf of the other COMPANIES, shall pay to the PROVINCE or under its direction to the Trusts or Trust Funds to be set up by the PROVINCE, as initial payment, the total amounts indicated hereinafter, which shall be transferred to the accounts stated by the PROVINCE: A) To the account of the concession fee to enter the area

(renegotiation concession fee), the amount of United States dollars 6.971.652 (u$s   six million, nine hundred and seventy one thousand, six hundred and fifty two), with the aim of financing infrastructure works, investments under development and projects related to production, tourism, culture, sports, health, security, human, neighborhood, rural, regional and environmental promotion, alternative energies, housing improvements, divisions of land into lots with services, and equipments, and satisfying works and credits originated in productive and regional and social promotion investments. B) To the account for Municipal development and promotion, the amount of United States dollars 1.682.813 (u$s one million, six hundred and eighty two thousand, eight hundred and thirteen), with the aim of financing programs for the promotion of the community and the development of municipalities, works and equipment applicable as set forth by the provincial legislation, with the purpose of environmental cleaning up, drinking water, treatment of waste, electrification, laying of gas pipes, resurfacing work, urbanization, industrial parks and others established by the act that approves this Memorandum of Agreement. C) To the account for the province development and promotion, the amount of United States dollars 2.564.285 (u$s two million, five hundred and sixty four, two hundred and eighty five), with the aim of financing a Development Program with the purpose of ensuring territory integration and environmental care, guaranteeing general welfare and prosperity. (If necessary, these funds shall be intended for financing the aims in point A).  -The payments to these accounts shall be made effective in monthly installments at the sell exchange rate of the Banco Nación Argentina at the close of the third day prior to the payment, according to the following details and conditions: 3.1.1 The first installment shall be paid within the ten first running days after this Memorandum of Agreement becomes effective pursuant to Section 5 herein, in the total amount of United States dollars 590.474 (u$s Five hundred and ninety, four hundred and seventy four). 3.1.2 As from July 2009

 inclusive, eighteen (18) equal and successive monthly installments shall be paid becoming due within the first ten working days of each month, each one in the amount of United States dollars 590.460  (u$s Five hundred and ninety, four hundred and sixty). 3.1.3 To the effect of providing documentary evidence of the payment obligations undertaken in this SECTION 3.1, within 72 hours as from the date on which this Memorandum of Agreement becomes effective (pursuant to the provisions of SECTION 5), PELSA as operator of the Concessions and acting on behalf of the COMPANIES shall subscribe and deliver to the order of the PROVINCE nineteen (19) promissory notes in accordance with the provisions stated in Annex IV. Each promissory note above mentioned shall be returned by the PROVINCE to PELSA within five working days after the obligation they guarantee is honored by the COMPANY.   3.2 EXTRAORDINARY PRODUCTION ROYALTY: The COMPANIES shall pay the PROVINCE on a monthly basis and in cash THREE PER CENT (3%) of the accountable production of Crude Oil and Natural Gas of each one of the exploitation concessions they own as mentioned in SECTION 1 herein, appraised according to the provisions of section 56, subsection c) paragraph I of Act 17319, upon the specifications set forth herein and the deductions and adjustments provided for in National Executive Order 1671/69 and others in accordance therewith and the provisions of the resolutions of the Energy Secretariat 155/92, 435/04, 188/93, 73/94 and their applicable modifications and substitutions. The payment of the Extraordinary Royalty shall begin to accrue as from the month following the entering into force of the Memorandum of Agreement, and the maturity dates shall operate for the advance payment the fifteenth day of the month following the month of settlement or the following working day if said day is a public holiday. The final declaration shall be on the fifteenth day of the month following the month of settlement or the following working day if said day is a public holiday. The sell exchange rate to be considered shall be that of the Banco Nación Argentina at the close of

the third working