1. DeGolyer and MacNaughton
5001 Spring Valley Road
Suite 800 East
Dallas, Texas 75244
This is a digital representation of a DeGolyer and MacNaughton report.
This file is intended to be a manifestation of certain data in the subject report and as such are
subject to the same conditions thereof. The information and data contained in this file may be
subject to misinterpretation; therefore, the signed and bound copy of this report should be
considered the only authoritative source of such information.

2. DeGolyer and MacNaughton
5001 Spr ing Valley Road
Suite 800 East
Dallas, Texas 75244
August 31, 2010
Petróleo Brasileiro S.A.
Av. República de Chile 65
Sala 1702C
Rio de Janeiro-RJ-Brazil
CEP 20035-900
Gentlemen:
Pursuant to your request, we have conducted an economic evaluation of the
potential present worth of potential future net revenues of certain prospective and
contingent resources located in the Santos Basin, offshore from Brazil. The details of
the prospective resources evaluation are contained in our report entitled “Report as
of July 1, 2010 on the Prospective Resources of Certain Prospects located Offshore
Brazil” (the Prospective Resources Report). The contingent resources evaluation is
detailed in our report entitled “Report as of July 1, 2010 on the Contingent
Resources of Certain Properties located Offshore Brazil” (the Contingent Resources
Report).
This letter report has been prepared considering the provisions of the process
known as transfer of rights with compensation. This process involves the transfer of
rights by the Government of Brazil to Petróleo Brasileiro S.A. (Petrobras) to produce
up to 5 billion barrels of oil equivalent (boe) in pre-salt reservoirs located in certain
non-licensed areas in the Santos Basin. In compensation for this transfer of rights,
Petrobras has represented that it will pay the Government of Brazil an amount
based upon a negotiated price per boe of the potentially recoverable volumes.
The prospects included in the original portfolio studied included in the
Prospective Resouces Report were the following:
1. Tupi Northeast
2. Tupi South
3. Guara East
4. Peroba

3. 2
DeGolyer and MacNaughton
5. Florim
6. Libra
7. Pau Brasil
8. Southwest Jupiter
For the prospective resources, the Prospective Resources Report documents
the estimates of prospective resources and corresponding potential present worth of
potential future net revenues in each area should such resources be successfully
discovered and developed. For the Prospective Resources Report at Petrobras’
request, the Libra, Pau Brasil, and Southwest Jupiter areas have been removed
from the portfolio.
For the contingent resources, the Contingent Resources Report documents
the estimates of contingent resources and corresponding potential present worth of
potential future net revenues in the following areas should such resources be
successfully developed:
1. Franco
2. Iara Offblock
Petrobras requested that we prepare a summary table showing the results of
potential future net revenue calculations for the “success case,” derived from the
development and production of the truncated and TEFS-adjusted mean volumes
estimated in the Prospective Resources Report. The success case scenario is based on
a deterministic development scenario that was not adjusted for the probability of
geologic risk (Pg) nor the probability of economic risk (Pe), and is thus an unlikely
outcome. This scenario has been evaluated based upon Petrobras’ representation
that the terms and conditions of the “transfer of rights with compensation” contract
(herein termed “the Contract”) being negotiated with the Government of Brazil
contains revision and reallocation clauses that guarantee the volume being
contracted. According to such terms and conditions, in the event a prospect or area
under the Contract does not produce the volume contracted, such volume may be
reallocated to another prospect or area under the same Contract. In the event the
reallocation procedure does not generate sufficient volumes equal to the contracted
volume, the Government of Brazil will reimburse Petrobras for the amount
equivalent to the volume not produced.
In addition, Petrobras requested that we prepare a summary table showing
the results of potential future net revenue calculations for the success case derived

4. 3
DeGolyer and MacNaughton
from the development and production of the 1C, 2C, and 3C contingent resources
estimated in the Contingent Resources Report.
Oil and gas prices used in this evaluation were provided by Petrobras. A
Brent marker crude price of U.S.$79.23 per barrel was used and held constant for
the life of the forecast. A discount of 7.92 percent was applied to the marker price to
account for crude gravity differential and transportation. A fixed wellhead sales gas
price of U.S.$4.27 per thousand cubic feet was used in the evaluation. Estimated
capital and operating expenditures potentially required for development of the
estimated prospective and contingent resources identified have not been escalated or
adjusted for possible inflation.
In this study, potential present worth values were estimated using a discount
rate of 10 percent.
Table 1 attached shows the results of the success case evaluation for the
prospective resources. The success case mean potential present worth per boe is
reported in Table P1 of the Prospective Resources Report. The estimates of potential
present worth presented in Table 1 attached are predicated on the small chance that
all of the prospects are geologic successes and can be economically developed.
Table 2 attached shows the results of the success case evaluation for the
contingent resources in the Franco and Iara Offblock areas.
A possibility exists that none of the prospects will result in successful
discoveries and development, in which case there would be no potential present
worth. There is no certainty that any portion of the prospective resources estimated
herein will be discovered. If discovered, there is no certainty that it will be
commercially viable to produce any portion of the prospective resources evaluated.
Prospective resources quantities estimates should not be confused with those
quantities that are associated with contingent resources or reserves due to the
additional risks involved. Contingent resources quantities estimates should not be
confused with those quantities that are associated with reserves due to the
additional risks involved.
The estimated potential present worth of potential future net revenue for the
prospective resources cannot be compared directly to, equated with, or aggregated
with the potential present worth estimates that could be realized from contingent

6. TABLE 1
ESTIMATION of SUCCESS CASE POTENTIAL VALUE
of the
PROSPECTIVE RESOURCES
of
CERTAIN AREAS
in
BRAZIL
as of
JULY 1, 2010
Gross Truncated
Success Case TEFS Adjusted
Mean Potential Success Case P Mean Success Case
Present Worth Mean Potential Prospective Resources Potential
per Barrel of Oil Present Worth Barrels of Oil Present Worth
Equivalent per Barrel of Oil Equivalent Value @ 10%
6
Prospect (U.S.$/boe) (U.S.$/bbl) (10 boe) (106 U.S. $)
Florim 7.07 7.98 467 3,301
NE Tupi 6.24 7.25 428 2,668
Guara East 5.18 5.85 319 1,651
Tupi South 6.12 6.87 128 784
Peroba 6.99 7.99 1,796 12,556
Note:
1. Potential present worth of potential future net revenue is shown using a discount rate of 10 percent.
2. Gas was converted to barrels of oil equivalent by applying a ratio of 6,000 standard cubic feet per barrel of oil.

7. TABLE 2
ESTIMATION of SUCCESS CASE POTENTIAL VALUE
of the
CONTINGENT RESOURCES
of
CERTAIN AREAS
in
BRAZIL
as of
JULY 1, 2010
Success Case Gross
Potential Success Case Contingent Success Case
Present Worth Potential Resources Potential
per Barrel of Oil Present Worth Barrels of Oil Present Worth
Equivalent per Barrel of Oil Equivalent Value @ 10%
6
Area (U.S.$/boe) (U.S.$/bbl) (10 boe) (106 U.S. $)
1C Contingent Resources
Franco 8.14 9.19 439 3,571
2C Contingent Resources
Iara Offblock 3.73 4.11 91 341
Franco 7.43 8.39 2,040 15,160
3C Contingent Resources
Iara Offblock 4.18 4.60 1,088 4,548
Franco 5.34 6.03 6,056 32,340
Note:
1. Potential present worth of potential future net revenue is shown using a discount rate of 10 percent.
2. Gas was converted to barrels of oil equivalent by applying a ratio of 6,000 standard cubic feet per barrel of oil.

8. DeGolyer and MacNaughton
GLOSSARY of TERMS
1C – Denotes low estimate scenario of contingent resources.
2C – Denotes best estimate scenario of contingent resources.
3C – Denotes high estimate scenario of contingent resources.
Contingent Resources – Those quantities of petroleum estimated, as of a given date,
to be potentially recoverable from known accumulations by application of
development projects, but which are not currently considered to be commercially
recoverable due to one or more contingencies.
Mean Estimate – In accordance with petroleum industry standards, the mean
estimate is the probability-weighted average, which typically has a probability in
the P45 to P15 range, depending on the variance of prospective resources volume or
associated value. Therefore, the probability of a prospect or accumulation
containing the probability weighted average volume or greater is usually between
45 and 15 percent. The mean estimate is the preferred probabilistic estimate of
resources volumes.
Potential Future Gross Revenue – Potential future gross revenue is that revenue
which will accrue to Petrobras from the potential production and sale of the
estimated potentially recoverable quantities should such quantities be successfully
discovered and/or developed.
Potential Future Net Revenue – Potential future net revenue is calculated by
deducting estimated royalties, operating expenses, capital costs, abandonment
costs, and income taxes from the potential future gross revenue.
Potential Present Worth of Future Net Revenue – Potential present worth of potential
future net revenue is defined as potential future net revenue discounted at a
specified arbitrary rate compounded monthly over the expected period of
realization. In this appraisal, potential present worth values were estimated using
a discount rate of 10 percent.

9. DeGolyer and MacNaughton
Probability of Economic Success – The probability of economic success (Pe) is defined
as the probability that a given discovery will be economically viable. It takes into
account Pg, PTEFS, TEFS, capital costs, operating expenses, the proposed
development plan, the economic model (discounted cash flow analyses), and other
business and economic factors. Pe is calculated as follows:
Pe = Pg  PTEFS
Probability of Geologic Success – The probability of geologic success (Pg) is defined as
the probability of discovering reservoirs that flow petroleum at a measurable rate.
Pg is estimated by quantifying with a probability each of the following individual
geologic chance factors: trap, source, reservoir, and migration. The product of the
probabilities of these four chance factors is Pg.
Probability of TEFS – The probability of threshold economic field size (PTEFS) is
defined as the probability of discovering an accumulation that is large enough to be
economically viable. PTEFS is estimated by using the prospective resources
recoverable volumes distribution in conjunction with the TEFS. The probability
associated with the TEFS can be determined graphically from the prospective
gross recoverable volumes distribution.
Prospect – A prospect is a potential accumulation that is sufficiently well defined to
be a viable drilling target. For a prospect, sufficient data and analyses exist to
identify and quantify the technical uncertainties, to determine reasonable ranges
of geologic chance factors and engineering and petrophysical parameters, and to
estimate prospective resources. In addition, a viable drilling target requires that
70 percent of the median potential production area be located within the block or
license area of interest.
Prospective Resources – Those quantities of petroleum that are estimated, as of a
given date, to be potentially recoverable from undiscovered accumulations by
application of future development projects.
Threshold Economic Field Size – The threshold economic field size (TEFS) is the
minimum amount of the producible petroleum required to recover the total
capital and operating expenditure used to establish the potential accumulation as
having a potential present worth equal to zero.

10. DeGolyer and MacNaughton
Truncated Mean Estimate – The truncated mean estimate is the resulting expected
value calculated from the truncation of the resources distribution by the threshold
economic field size. This truncated distribution produces a new set of statistical
metrics.