1. OGX: 2Q11 Results

2. Disclaimer This presentation uses the terms “prospective resources” and “contingent resources” to describe those quantities of petroleum that are potentially recoverable from accumulations yet to be discovered. Because of the uncertainty to commerciality and lack of sufficient exploration drilling, prospective resources cannot be classified as reserves. Investors are advised that the U.S. Securities and Exchange Commission (SEC) and other international securities regulators do not recognize prospective and contingent resources. Prospective resources have a great amount of uncertainty as to their existence. There is no certainty that any portion of the prospective resources will be discovered and, if discovered, whether they could be developed economically. Therefore, investors are cautioned not to assume that all or any part of OGX’s prospective resources exist, or that they can be developed economically. Accordingly, information concerning prospective and contingent resources contained in this presentation are not comparable to information permitted to be made public by U.S. or other international companies subject to SEC reporting and disclosure requirements, especially Industry Guide 2 under the Securities Act. Certain of the information and conclusions set forth herein are based on projections. These projections were prepared for the limited purpose of analyzing the potential risks and benefits of an investment in the securities by illustrating under certain limited assumptions. In addition, because of the subjective judgments and inherent uncertainties of projections and because the projections are based on a number of assumptions, which are subject to significant uncertainties and contingencies that are beyond the control of OGX, there can be no assurance that the projections or conclusions derived therefrom will be realized. Under no circumstances should the projections set forth herein be regarded as a representation, warranty or prediction that OGX will achieve or is likely to achieve any particular future result. There can be no assurance that OGX’s future results or projections will not vary significantly from those set forth herein. Accordingly, investors may lose all of their investment to the extent the projections or conclusions included herein are not ultimately realized. This presentation also contains forward-looking statements, which may be identified by such words as "may", "plans", "expects", "believes" and similar expressions, or by their context. These statements are made on the basis of current knowledge and, by their nature, involve numerous assumptions and uncertainties. Various factors could cause OGX's actual future results, performance or events to differ materially from those described in this presentation. In no event shall the Company or the members of its board, directors, assigns or employees be liable to any third party (including investors) for investment decisions or acts or business carried out based on the information and statements that appear in this presentation, or for indirect damage, lost profit or related issues. The Company does not intend to provide to potential shareholders with a revision of the statements or an analysis of the differences between the statements and the actual results. You are urged to carefully review OGX's offering circular, including the risk factors included therein. This presentation does not purport to be all-inclusive or to contain all the information that a prospective investor may desire in evaluating OGX. Each investor must conduct and rely on its own evaluation, including of the associated risks, in making an investment decision. 2

3. 2Q11 Highlights and Subsequent Events First oil expected in October/November 2011 Horizontal well OGX-26HP (Waimea) prepared for start-up of production All key equipment already secured and delivered FPSO OSX-1 expected to arrive in September Important new discoveries announced during the quarter Campos Basin: OGX-33 (Chimborazo) and OGX-52 (Tambora) Parnaíba Basin: OGX-34 (Bom Jesus) Santos Basin: OGX-30 (Salvador) and OGX-47 (Maceió) Continued intensification of appraisal campaign 11 wells in Campos Basin, 2 wells in Parnaíba Basin New drill-stem tests in horizontal wells OGX-39HP (Pipeline) and OGX-44HP (Waikiki) in the Campos Basin New tests to be performed in Campos and Santos Basins Declaration of commerciality in the Parnaíba Basin 2 fields: Gavião Real and GaviãoAzul Successful $2.6bn bond offering 3

4. Financial ResultsHighlights

6. Exploration Expenses: Primarily related to the acquisition of seismic data in the Parnaíba, Espírito Santo and Campos basins

7. General and Administrative Expenses: Increase in the number of employees from 184 to 266 between 2Q10 and 2Q11 and the stock options plan

8. Intangibles: Impacted by the intensification of our drilling campaign mainly in Campos, Santos and Parnaíba Basins5

10. Moody’s, Fitch and S&P gave OGX B1, B+ and B (positive outlook) ratings, respectively

11. Largest non-investment grade offering ever in the industryInvestor Breakdown LAtam 3% Asia 3% Europe 18% US 78% 6

13. Foreign exchange hedge position of approximately US$ 901.2 million, representing approximately 5 months of financial commitments denominated in US$

14. Cash allocated in R$: Average cumulative gross return equivalent to approximately 103.6% of the Interbank Deposit Rate (CDI), or 11.7% p.a., generating R$223.4 million of interest income for the period

15. Cash Allocated in US$: Average cumulative gross return equivalent to approximately 1.5% p.a, generating US$ 2.8 million of interest income for the period.

16. Cash invested in fixed income instruments with some of the most solid financial institutions in Brazil7

17. Path to Production

19. Oilqualityof 20° API

20. Waterdepthof 140 metersFlexible lines delivered Anchor system (moorings and piles) delivered Installation support vessel delivered EWT approved by ANP (National Petroleum Agency) Electricalsubmersiblepump Horizontal Well OGX first oil expected for October/November through Extended Well Test (EWT) Illustrative frames 9

21. Final StepsTowardsProduction Flexible lines / umbilicals connection and risers installation Mooringsand Piles installation Arrival of the FPSO OSX-1 Beginningofproduction 1 3 2 Arrival of the Buoy and installation Buoy hook-up and connection to the FPSO 5 4 6 Illustrative frames 10

23. 3 horizontal production wells

24. 1st production well, OGX-26HP, ready for production

25. 2nd production well, OGX-55HP, currently being drilled

26. 3rd production well, OGX-53D, currently being drilled

27. Average production per well 10–20 kbpd

28. 2 subsea injection wells

29. 1 FPSO: OSX-1

30. OSX-1 expected arrival for September/2011

31. OGX-55HP and OGX-53D wells to be hooked-up to OSX-1 after the declaration of commerciality next year

32. With 3 production wells on stream, OGX should reach production levels of ~50 kbpdProductionWell 1 (OGX-26HP) ProductionWell 3 (OGX-53D) InjectionWell 2 InjectionWell 1 ProductionWell 2 (OGX-55HP) Development Wells Illustrative frame 11

34. OSX-1 (expected arrival for Sep/11)

35. OSX-2 (under development by SBM)

37. OSX-3 (under development by Modec)

38. WHP-2 (engineered by Techint)Module N Module 4 Module 3 Module 2 Module 1 Illustrative frame 12

40. Initial production expected in 2H12

41. Second seismic crew contracted to work on the southern blocks

42. Recently approved leasing agreement of 2 additional rigs

43. MPX has obtained an additional 1,859 MW of installation license, totaling 3,722 MW

44. MPX acquired 2 projects from Bertin with a total capacity of 660 MW, which will be transferred to Parnaíba’s Complex after ANEEL’s approvalGavião Azul Gavião Real Legend: Seismic Lines 13

45. Exploratory Campaign

46. Campos Basin: Focusing on Wildcat & Appraisal Wells Wildcat Wells Appraisal Wells Note:1 Numbers indicate the well drilling area as per D&M’s Dec/10 reports and net pay 26 wildcat wells and 19 appraisal wells drilled with hydrocarbons and results which support expectations 15

48. Oil Quality of 20o API

50. Oil Quality of 23o API

52. Oil Quality of 19o API

53. Tested in Jul/20113 drill-stem tests already performed in horizontal wells prepared for production and more to come in the second half 16

54. Parnaíba Basin: Rapid Declaration of Commerciality Appraisal Wells Wildcat Wells Note:1 Numbers indicate the well drilling area as per D&M’s Dec/10 reports and net pay Declaration of commerciality declared only 20 months after beginning of exploration campaign 17

55. Santos Basin: New Significant Discoveries Wildcat Wells Recent discoveries OGX-30 (Salvador) and OGX-47 (Maceió) tested classic targets and new geological models reinforcing the gas province in the Basin 18

57. Commercialization contracts for first oil sale prior to the beginning of production

58. Continue appraisal campaign in the Campos and Parnaíba Basins

59. Commencement of the drilling campaign in the Espírito Santo and Pará-Maranhão Basins in 2H11

60. New drill-stem tests in Campos, Santos and Parnaíba Basins

61. Beginning of exploratory campaign in Colombia initiating seismic shooting and interpretation

62. Participation on ANP next bidding rounds19