Exhibit 99.1

Mitsui & Co., Ltd.

Estimated

Future Net Remaining Reserves

Attributable to Certain Interests In

Australia, New Zealand and
Indonesia

SEC Parameters

As of

December 31, 2009



|                                             |  |  |  |                                    
|-------------------------------------------- |  |  |  | -----------------------------------
|/s/ Herman G. Acuña                          |  |  |  | /s/ Harris Ghozali                 
|Herman G. Acuña, P.E.                        |  |  |  | Harris Ghozali, P.E.               
|Texas P.E. License No. 92254                 |  |  |  | Texas P.E. License No. 97664       
|Managing Senior Vice PresidentInternational |  |  |  | Senior Vice PresidentInternational

RYDER SCOTT COMPANY, L.P.

TBPE Firm Registration No. F-1580



|       |  |  |  |       
|------ |  |  |  | ------
|[SEAL] |  |  |  | [SEAL]



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June 28, 2010

Mitsui & Co., Ltd.

2-1, Ohtemachi
1-chome,

Chiyoda-ku, Tokyo 100-0004

Japan

Gentlemen:

At the request of Mitsui & Co., Ltd. and its affiliated companies, Japan Australia LNG (MIMI) Pty. Ltd., Mitsui E&P Australia
Pty Limited, KG Berau Petroleum Ltd. and KG Wiriagar Petroleum Ltd., (hereinafter collectively called MITSUI), Ryder Scott Company (Ryder Scott) has prepared an estimate of the proved reserves, future production and income attributable
to certain properties of MITSUI, as of December 31, 2009. The subject properties are located in the countries of Australia, New Zealand and Indonesia.

The reserves and income data were estimated based on the definitions and disclosure guidelines of the United States Securities and Exchange Commission (SEC) contained in Title 17, Code of Federal
Regulations, Modernization of Oil and Gas Reporting, Final Rule released January 14, 2009 in the Federal Register (SEC regulations). Our third party study, completed on June 24, 2010 and presented herein, was prepared for public disclosure
by MITSUI in filings made with the SEC in accordance with the disclosure requirements set forth in the SEC regulations.

The
properties evaluated by Ryder Scott account for a portion of MITSUIs total net proved reserves as of December 31, 2009. Based on information provided by MITSUI, the third party estimate conducted by Ryder Scott addresses 50 percent of the
total proved developed net liquid hydrocarbon reserves, 47 percent of the total proved developed net gas reserves, 53 percent of the total proved undeveloped net liquid hydrocarbon reserves, and 73 percent of the total proved undeveloped net gas
reserves of MITSUI.

The estimated reserve amounts presented in this report, as of December 31, 2009, are related to
hydrocarbon prices. The hydrocarbon prices used in the preparation of this report are based on the average prices during the 12-month period prior to the ending date of the period covered in this report, determined as the unweighted arithmetic
averages of the prices in effect on the first-day-of-the-month for each month within such period, unless prices were defined by contractual arrangements, as required by the SEC regulations. Actual future prices may vary significantly from the prices
required by SEC regulations; therefore, volumes of reserves actually recovered may differ significantly from the estimated quantities presented in this report. The results of this study are summarized in the following table.



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Mitsui & Co., Ltd.

June 28, 2010

Page 2

SEC PARAMETERS

Estimated Net Remaining Reserves

Certain Interests of

Mitsui & Co., Ltd.

As of December 31, 2009



|                         |  |           |            |  |             |  |            |             |  |  |            | 
|------------------------ |  | --------- | ---------- |  | ----------- |  | ---------- | ----------- |  |  | ---------- | 
|                         |  | Proved    |           
|                         |  | Developed |            |  | Undeveloped |  |            | TotalProved | 
|Australia/Oceania        |  |           |            |  |             |  |            |             |  |  |            | 
|Oil/Condensate  Barrels |  |           | 35,085,354 |  |             |  | 16,839,061 |             |  |  | 51,924,415 | 
|Plant Products  Barrels |  |           | 2,857,130  |  |             |  | 3,183,257  |             |  |  | 6,040,387  | 
|Sales Gas  MMCF         |  |           | 327,406    |  |             |  | 402,487    |             |  |  | 729,893    | 
|                         |  |           |           
|Thailand/Asia            |  |           |            |  |             |  |            |             |  |  |            | 
|Oil/Condensate  Barrels |  |           | 145,022    |  |             |  | 194,229    |             |  |  | 339,251    | 
|Plant Products  Barrels |  |           | 53,504     |  |             |  | 76,697     |             |  |  | 130,201    | 
|Sales Gas  MMCF         |  |           | 50,807     |  |             |  | 93,352     |             |  |  | 144,159    | 
|                         |  |           |           
|Total                    |  |           |            |  |             |  |            |             |  |  |            | 
|Oil/Condensate  Barrels |  |           | 35,230,376 |  |             |  | 17,033,290 |             |  |  | 52,263,666 | 
|Plant Products  Barrels |  |           | 2,910,634  |  |             |  | 3,259,954  |             |  |  | 6,170,588  | 
|Sales Gas  MMCF         |  |           | 378,213    |  |             |  | 495,839    |             |  |  | 874,052    | 

Liquid hydrocarbons
are expressed in standard 42 gallon barrels. All gas volumes are reported on an as sold basis expressed in millions of cubic feet (MMCF) at a temperature base of 60 degrees Fahrenheit and pressure base of 14.696 psia.

Reserves Included in This Report

The proved reserves included herein conform to the definition as set forth in the Securities and Exchange Commissions Regulations Part 210.4-10(a). An abridged version of the SEC reserves
definitions from 210.4-10(a) entitled Petroleum Reserves Definitions is included as an attachment to this report. The various proved reserve status categories are defined under the attachment entitled Petroleum Reserves
Definitions in this report.

No attempt was made to quantify or otherwise account for any accumulated gas production
imbalances that may exist. The proved gas volumes included herein do not attribute gas consumed in operations as reserves. Non-hydrocarbon or inert gas volumes have been excluded from the reserves reported herein.

Reserves are those estimated remaining quantities of petroleum that are anticipated to be economically producible, as of a given date,
from known accumulations under defined conditions. All reserve estimates involve an assessment of the uncertainty relating the likelihood that the actual remaining quantities recovered will be greater or less than the estimated quantities determined
as of the date the estimate is made. The uncertainty depends chiefly on the amount of reliable geologic and engineering data available at the time of the estimate and the interpretation of these data. The relative degree of uncertainty may be
conveyed by placing reserves into one of two principal classifications, either proved or unproved. Unproved reserves are less certain to be recovered than proved reserves, and may be further sub-classified as probable and possible reserves to denote
progressively increasing uncertainty in their recoverability. At MITSUIs request, this report addresses only the proved reserves attributable to the properties evaluated herein.



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Mitsui & Co., Ltd.

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Page 3

Proved oil and gas reserves are those quantities of oil and gas which, by analysis of
geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from a given date forward. The proved reserves included herein were estimated using deterministic methods. If deterministic methods are used,
the SEC has defined reasonable certainty for proved reserves as a high degree of confidence that the quantities will be recovered.

Proved reserve estimates will generally be revised only as additional geologic or engineering data become available or as economic conditions change. For proved reserves, the SEC states that as
changes due to increased availability of geoscience (geological, geophysical, and geochemical), engineering, and economic data are made to the estimated ultimate recovery (EUR) with time, reasonably certain EUR is much more likely to increase or
remain constant than to decrease. Moreover, estimates of proved reserves may be revised as a result of future operations, effects of regulation by governmental agencies or geopolitical or economic risks. Therefore, the proved reserves included
in this report are estimates only and should not be construed as being exact quantities, and if recovered, the revenues therefrom, and the actual costs related thereto, could be more or less than the estimated amounts.

The proved reserves reported herein are limited to the period prior to expiration of current contracts providing the legal rights to
produce, or a revenue interest in such production, unless evidence indicates that contract renewal is reasonably certain. Furthermore, properties in the different countries may be subjected to significantly varying contractual fiscal terms that
affect the net revenue to MITSUI for the production of these volumes. The prices and economic return received for these net volumes can vary significantly based on the terms of these contracts. Therefore, when applicable, Ryder Scott reviewed the
fiscal terms of such contracts and discussed with MITSUI the net economic benefit attributed to such operations for the determination of the net hydrocarbon volumes and income thereof. Ryder Scott has not conducted an exhaustive audit or
verification of such contractual information. Neither our review of such contractual information nor our acceptance of MITSUIs representations regarding such contractual information should be construed as a legal opinion on this matter.

Ryder Scott did not evaluate the country and geopolitical risks in the countries where MITSUI operates or has interests.
MITSUIs operations may be subject to various levels of governmental controls and regulations. These controls and regulations may include, but may not be limited to, matters relating to land tenure and leasing, the legal rights to produce
hydrocarbons including the granting, extension or termination of production sharing contracts, the fiscal terms of various production sharing contracts, drilling and production practices, environmental protection, marketing and pricing policies,
royalties, various taxes and levies including income tax, and foreign trade and investment and are subject to change from time to time. Such changes in governmental regulations and policies may cause volumes of proved reserves actually recovered and
amounts of proved income actually received to differ significantly from the estimated quantities.

The estimates of proved
reserves presented herein were based upon a detailed study of the properties in which MITSUI owns an interest; however, we have not made any field examination of the properties. No consideration was given in this report to potential environmental
liabilities that may exist nor were any costs included for potential liabilities to restore and clean up damages, if any, caused by past operating practices.



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Mitsui & Co., Ltd.

June 28, 2010

Page 4

Estimates of Reserves

The estimation of reserves involves two distinct determinations. The first determination results in the estimation of the quantities of recoverable oil and gas and the second determination results in the
estimation of the uncertainty associated with those estimated quantities in accordance with the definitions set forth by the Securities and Exchange Commissions Regulations Part 210.4-10(a). The process of estimating the quantities of
recoverable oil and gas reserves relies on the use of certain generally accepted analytical procedures. These analytical procedures fall into three broad categories or methods: (1) performance-based methods; (2) volumetric-based methods;
and (3) analogy. These methods may be used singularly or in combination by the reserve evaluator in the process of estimating the quantities of reserves. Reserve evaluators must select the method or combination of methods which in their
professional judgment is most appropriate given the nature and amount of reliable geoscience and engineering data available at the time of the estimate, the established or anticipated performance characteristics of the reservoir being evaluated and
the stage of development or producing maturity of the property.

In many cases, the analysis of the available geoscience and
engineering data and the subsequent interpretation of this data may indicate a range of possible outcomes in an estimate, irrespective of the method selected by the evaluator. When a range in the quantity of reserves is identified, the evaluator
must determine the uncertainty associated with the incremental quantities of the reserves. If the reserve quantities are estimated using the deterministic incremental approach, the uncertainty for each discrete incremental quantity of the reserves
is addressed by the reserve category assigned by the evaluator. Therefore, it is the categorization of reserve quantities as proved, probable and/or possible that addresses the inherent uncertainty in the estimated quantities reported. For proved
reserves, uncertainty is defined by the SEC as reasonable certainty wherein the quantities actually recovered are much more likely than not to be achieved. The SEC states that probable reserves are those additional reserves that
are less certain to be recovered than proved reserves but which, together with proved reserves, are as likely as not to be recovered. The SEC states that possible reserves are those additional reserves that are less certain to be
recovered than probable reserves and the total quantities ultimately recovered from a project have a low probability of exceeding proved plus probable plus possible reserves. All quantities of reserves within the same reserve category must
meet the SEC definitions as noted above.

Estimates of reserves quantities and their associated reserve categories may be
revised in the future as additional geoscience or engineering data become available. Furthermore, estimates of reserves quantities and their associated reserve categories may also be revised due to other factors such as changes in economic
conditions, results of future operations, effects of regulation by governmental agencies or geopolitical or economic risks as previously noted herein.

The proved reserves for the properties included herein were estimated by performance methods, material balance methods, the volumetric method, or a combination of performance and volumetric methods. The
following table summarizes the approximate percent of reserves estimated by each of these methods.



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Mitsui & Co., Ltd.

June 28, 2010

Page 5

Approximate Percent Proved Reserves Estimated by the Various Methods



|                 |  |           |             |   |                     |  |             |           |  |  |             |   |  |  |    |  
|---------------- |  | --------- | ----------- | - | ------------------- |  | ----------- | --------- |  |  | ----------- | - |  |  | -- | -
|                 |  | Gas       |             |   | Liquid Hydrocarbons | 
|Method           |  | Developed |             |   | Undeveloped         |  |             | Developed |  |  | Undeveloped |  
|Volumetric       |  |           | 62          | % |                     |  | 100         | %         |  |  | 77          | % |  |  | 85 | %
|Performance      |  |           | Less than 1 | % |                     |  | 0           | %         |  |  | 5           | % |  |  | 5  | %
|Material Balance |  |           | 5           | % |                     |  | 0           | %         |  |  | 4           | % |  |  | 0  | %
|Combination      |  |           | 33          | % |                     |  | Less than 1 | %         |  |  | 14          | % |  |  | 10 | %

These performance methods
include, but may not be limited to, decline curve analysis and material balance which utilized extrapolations of historical production and pressure data available through December, 2009 in those cases where such data were considered to be
definitive. The data utilized in this analysis were supplied to Ryder Scott by MITSUI and were considered sufficient for the purpose thereof. The volumetric method was used where there were inadequate historical performance data to establish a
definitive trend and where the use of production performance data as a basis for the reserve estimates was considered to be inappropriate. The volumetric analysis utilized pertinent well and seismic data supplied to Ryder Scott by MITSUI that were
available through December, 2009. The data utilized from the well and seismic data incorporated into our volumetric analysis were considered sufficient for the purpose thereof.

To estimate economically recoverable proved oil and gas reserves and related future net cash flows, we consider many factors and
assumptions including, but not limited to, the use of reservoir parameters derived from geological, geophysical and engineering data that cannot be measured directly, economic criteria based on current costs and SEC pricing requirements, and
forecasts of future production rates. Under the SEC regulations 210.4-10(a)(22)(v) and (26), proved reserves must be anticipated to be economically producible from a given date forward based on existing economic conditions including the prices and
costs at which economic producibility from a reservoir is to be determined. While it may reasonably be anticipated that the future prices received for the sale of production and the operating costs and other costs relating to such production may
increase or decrease from those under existing economic conditions, such changes were, in accordance with rules adopted by the SEC, omitted from consideration in making this evaluation.

MITSUI has informed us that they have furnished us all of the material accounts, records, geological and engineering data, and reports
and other data required for this investigation. In preparing our forecast of future proved production and income, we have relied upon data furnished by MITSUI with respect to property interests owned, production and well tests from examined wells,
normal direct costs of operating the wells or leases, other costs such as transportation and/or processing fees, ad valorem and production taxes, recompletion and development costs, abandonment costs after salvage, product prices based on the SEC
regulations, adjustments or differentials to product prices, geological structural and isochore maps, well logs, core analyses, and pressure measurements. Ryder Scott reviewed such factual data for its reasonableness; however, we have not conducted
an independent verification of the data furnished by MITSUI. We consider the factual data used in this report appropriate and sufficient for the purpose of preparing the estimates of reserves herein.



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Mitsui & Co., Ltd.

June 28, 2010

Page 6

In summary, we consider the assumptions, data, methods and analytical procedures used in
this report appropriate for the purpose hereof, and we have used all such methods and procedures that we consider necessary and appropriate to prepare the estimates of reserves herein. The proved reserves included herein were determined in
conformance with the United States Securities and Exchange Commission (SEC) Modernization of Oil and Gas Reporting; Final Rule, including all references to Regulation S-X and Regulation S-K, referred to herein collectively as the SEC
Regulations. In our opinion, the proved reserves presented in this report comply with the definitions, guidelines and disclosure requirements as required by the SEC regulations.

Future Production Rates

For wells currently on production, our
forecasts of future production rates are based on historical performance data. If no production decline trend has been established, future production rates were held constant, or adjusted for the effects of curtailment where appropriate, until a
decline in ability to produce was anticipated. An estimated rate of decline was then applied to depletion of the reserves. If a decline trend has been established, this trend was used as the basis for estimating future production rates.

Test data and other related information were used to estimate the anticipated initial production rates for those wells or locations that
are not currently producing. For reserves not yet on production, sales were estimated to commence at an anticipated date furnished by MITSUI. Wells or locations that are not currently producing may start producing earlier or later than anticipated
in our estimates due to unforeseen factors causing a change in the timing to initiate production. Such factors may include delays due to weather, the availability of rigs, the sequence of drilling, completing and/or recompleting wells and/or
constraints set by regulatory bodies.

The future production rates from wells currently on production or wells or locations
that are not currently producing may be more or less than estimated because of changes including, but not limited to, reservoir performance, operating conditions related to surface facilities, compression and artificial lift, pipeline capacity
and/or operating conditions, producing market demand and/or allowables or other constraints set by regulatory bodies.

Hydrocarbon
Prices

The hydrocarbon prices used herein are based on SEC price parameters using the average prices during the
12-month period prior to the ending date of the period covered in this report, determined as the unweighted arithmetic averages of the prices in effect on the first-day-of-the-month for each month within such period, unless prices were defined by
contractual arrangements. For hydrocarbon products sold under contract, the contract prices, including fixed and determinable escalations, exclusive of inflation adjustments, were used until expiration of the contract. Upon contract expiration, the
prices were adjusted to the 12-month unweighted arithmetic average as previously described.

MITSUI furnished us with the
above mentioned average prices in effect on December 31, 2009. These initial SEC hydrocarbon prices were determined using the 12-month average first-day-of-the-month benchmark prices appropriate to the geographic area where the hydrocarbons are
sold. These benchmark prices are prior to the adjustments for differentials as described herein. The table below summarizes the benchmark prices and price reference used for the geographic areas included in the report. In
certain geographic areas, the price reference and benchmark prices may be defined by contractual arrangements. In cases where there are numerous contracts or price references within the same geographic area, the benchmark price is represented by the
unweighted arithmetic average of the initial 12-month average first-day-of-the-month benchmark prices used.



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Mitsui & Co., Ltd.

June 28, 2010

Page 7

The product prices that were actually used to determine the future gross revenue for each
property reflect adjustments to the benchmark prices for gravity, quality, local conditions and/or distance from market, referred to herein as differentials. The differentials used in the preparation of this report were furnished to
us by MITSUI. The differentials furnished to us were accepted as factual data and reviewed by us for their reasonableness; however, we have not conducted an independent verification of the data used by MITSUI to determine these differentials.

In addition, the following table summarizes the net volume weighted benchmark prices adjusted for differentials and referred
to herein as the average realized prices. The average realized prices shown in the table below were determined from the total future gross revenue before production taxes and the total net reserves for the geographic area and presented
in accordance with SEC disclosure requirements for each of the geographic areas included in the report.



|                  |  |                |               |                    |   |                        |            |  |                       |   |           | 
|----------------- |  | -------------- | ------------- | ------------------ | - | ---------------------- | ---------- |  | --------------------- | - | --------- | 
|Geographic Area   |  | Product        |               | Price
Reference    |   | AverageBenchmarkPrices |            |  | AverageRealizedPrices |  
|                  |  |                |               | Brent (DTD)        |   | $                      | 60.15/Bbl  |  |                       |   |           | 
|                  |  | Oil/Condensate |               | Tapis (APPI)       |   | $                      | 61.95/Bbl  |  |                       | $ | 56.84/Bbl | 
|                  |  |                | Tapis (Platt) |                    | $ | 63.21/Bbl              |            | 
|Australia/Oceania |  |                |               | NWS Condensate     |   | $                      | 54.52/Bbl  |  |                       |   |           | 
|                  |  | NGLs           |               | Saudi CP           |   | $                      | 511.25/MT  |  |                       | $ | 61.92/Bbl | 
|                  |  |                | Tapis (APPI)  |                    | $ | 61.95/Bbl              |            | 
|                  |  | Gas            |               | JCC                |   | $                      | 60.60/Bbl  |  |                       | $ | 6.91/MCF  | 
|                  |  | Condensate/NGL |               | Dubai              |   | $                      | 64.40/Bbl  |  |                       | $ | 58.07/Bbl | 
|Thailand/Asia     |  | Gas            |               | JCC                |   | $                      | 60.60/Bbl  |  |                       | $ | 3.36/MCF  | 
|                  |  |                |               | SoCal Border (ICE) |   | $                      | 3.65/MMBTU |  |                      

Costs

Operating costs used in our evaluation were based on the operating expense reports of MITSUI and include only those costs directly
applicable to the evaluated assets. The operating costs include a portion of general and administrative costs allocated directly to the leases and wells. The operating costs furnished to us were accepted as factual data and reviewed by us for their
reasonableness; however, we have not conducted an independent verification of the operating cost data used by MITSUI. No deduction was made for loan repayments, interest expenses, or exploration and development prepayments that were not charged
directly to the assets.

Development costs were furnished to us by MITSUI and are based on authorizations for
expenditure for the proposed work or actual costs for similar projects. The development costs furnished to us were accepted as factual data and reviewed by us for their reasonableness; however, we have not conducted an independent verification of
these costs. The estimated net cost of abandonment after salvage was included for properties where abandonment costs net of salvage were significant. The estimates of the net abandonment costs furnished by MITSUI were accepted without independent
verification.



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Mitsui & Co., Ltd.

June 28, 2010

Page 8

The proved developed and undeveloped reserves in this report have been incorporated herein
in accordance with MITSUIs plans to develop these reserves as of December 31, 2009. The implementation of MITSUIs development plans as presented to us and incorporated herein is subject to the approval process adopted by
MITSUIs management. As the result of our inquires during the course of preparing this report, MITSUI has informed us that the development activities included herein have been subjected to and received the internal approvals required by
MITSUIs management at the appropriate local, regional and/or corporate level. In addition to the internal approvals as noted, certain development activities may still be subject to specific partner AFE processes, Joint Operating Agreement
(JOA) requirements or other administrative approvals external to MITSUI. Additionally, MITSUI has informed us that they are not aware of any legal, regulatory, political or economic obstacles that would significantly alter their plans.

Current costs used by MITSUI were held constant throughout the life of the properties.

Standards of Independence and Professional Qualification

Ryder Scott is an independent petroleum engineering consulting firm that has been providing petroleum consulting services throughout the world for over seventy years. Ryder Scott is employee-owned and
maintains offices in Houston, Texas; Denver, Colorado; and Calgary, Alberta, Canada. We have over eighty engineers and geoscientists on our permanent staff. By virtue of the size of our firm and the large number of clients for which we provide
services, no single client or job represents a material portion of our annual revenue. We do not serve as officers or directors of any publicly-traded oil and gas company and are separate and independent from the operating and investment
decision-making process of our clients. This allows us to bring the highest level of independence and objectivity to each engagement for our services.

Ryder Scott actively participates in industry-related professional societies and organizes an annual public forum focused on the subject of reserves evaluations and SEC regulations. Many of our staff have
authored or co-authored technical papers on the subject of reserves related topics. We encourage our staff to maintain and enhance their professional skills by actively participating in ongoing continuing education.

Prior to becoming an officer of the Company, Ryder Scott requires that staff engineers and geoscientists have received professional
accreditation in the form of a registered or certified professional engineers license or a registered or certified professional geoscientists license, or the equivalent thereof, from an appropriate governmental authority or a recognized
self-regulating professional organization.

We are independent petroleum engineers with respect to MITSUI. Neither we nor any
of our employees have any interest in the subject properties and neither the employment to do this work nor the compensation is contingent on our estimates of reserves for the properties which were reviewed.

The results of this study, presented herein, are based on technical analysis conducted by teams of geoscientists and engineers from Ryder
Scott. The professional qualifications of the undersigned, the technical persons primarily responsible for overseeing, reviewing and approving the evaluation of the reserves information discussed in this report, are included as an attachment to this
letter.



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Mitsui & Co., Ltd.

June 28, 2010

Page 9

Terms of Usage

The results of our third party study, presented in report form herein, were prepared in accordance with the disclosure requirements set forth in the SEC regulations and intended for public disclosure as
an exhibit in filings made with the SEC by MITSUI.

We have provided MITSUI with a digital version of the original signed copy
of this report letter. In the event there are any differences between the digital version included in filings made by MITSUI and the original signed report letter, the original signed report letter shall control and supersede the digital version.

The data and work papers used in the preparation of this report are available for examination by authorized parties in our
offices. Please contact us if we can be of further service.



Very truly yours,RYDER SCOTT COMPANY, L. P.TBPE Firm Registration No. F-1580/s/ Harris GhozaliHarris Ghozali, P.E.

[SEAL]Texas P.E. License No. 97664Senior Vice PresidentInternational/s/ Herman G. AcuñaHerman G. Acuna, P.E.

[SEAL]Texas P.E. License No. 92254Managing Senior Vice PresidentInternational


HGA/sm



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Professional Qualifications

Harris Ghozali

The
conclusions presented in this report are the result of technical analysis conducted by teams of geoscientists and engineers from Ryder Scott Company, L.P. Harris Ghozali was a primary technical person responsible for the estimate of the reserves,
future production and income presented herein.

Mr. Ghozali, an employee of Ryder Scott Company L.P. (Ryder Scott) since 1997, is a
Senior Vice President and an Engineering Group Coordinator responsible for coordinating and supervising staff and consulting engineers of the company in ongoing reservoir evaluation studies worldwide. Before joining Ryder Scott, Mr. Ghozali
served in a number of engineering positions with ExxonMobil. For more information regarding Mr. Ghozalis geographic and job specific experience, please refer to the Ryder Scott Company website at www.ryderscott.com/Experience/Employees.

Mr. Ghozali earned a Bachelor of Science degree in Petroleum Engineering from the Colorado School of Mines in 1991 and a Master of
Science degree in Petroleum Engineering from the University of Houston in 1997. He is a registered Professional Engineer in the State of Texas and also a member of the Society of Petroleum Engineers.

As part of his 2009 continuing education hours, Mr. Ghozali attended an internally presented 13 hours of formalized SEC-related training as well as
a day long public forum, and/or various professional society presentations specifically on the new SEC regulations relating to the definitions and disclosure guidelines contained in the United States Securities and Exchange Commission Title 17, Code
of Federal Regulations, Modernization of Oil and Gas Reporting, Final Rule released January 14, 2009 in the Federal Register. Mr. Ghozali attended an additional 7 hours of formalized in-house training as well as 10 hours of formalized
external training during 2009 covering such topics as the SPE/WPC/AAPG/SPEE Petroleum Resources Management System, reservoir engineering, geoscience and petroleum economics evaluation methods, procedures and software and ethics for consultants.
Mr. Ghozali is also an instructor and has taught several one day and three day seminars on Hydrocarbon Reserves and Resources Evaluation Methods.

Based on his educational background, professional training and more than 19 years of practical experience in the estimation and evaluation of petroleum reserves, Mr. Ghozali has attained the
professional qualifications as a Reserves Estimator and Reserves Auditor set forth in Article III of the Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information promulgated by the Society of Petroleum
Engineers as of February 19, 2007.



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Professional Qualifications

Herman G. Acuña

The conclusions presented in this report are the result of technical analysis conducted by teams of geoscientists and engineers from Ryder Scott Company,
L.P. Herman G. Acuña was a primary technical person responsible for overseeing the independent estimation of the reserves, future production and income to render the audit conclusions of that report.

Mr. Acuña, an employee of Ryder Scott Company L.P. (Ryder Scott) since 1997, is a Managing Senior International Vice President and serves as
an Engineering Group Coordinator responsible for coordinating and supervising staff and consulting engineers of the company in ongoing reservoir evaluation studies worldwide. Before joining Ryder Scott, Mr. Acuña served in a number of
engineering positions with Exxon. For more information regarding Mr. Acuñas geographic and job specific experience, please refer to the Ryder Scott Company website at www.ryderscott.com/Experience/Employees.

Mr. Acuña earned a Bachelor (Cum Laude) and a Masters (Magna Cum Laude) of Science degree in Petroleum Engineering from The University of
Tulsa in 1987 and 1989 respectively. He is a registered Professional Engineer in the State of Texas, a member of the Association of International Petroleum Negotiators (AIPN) and the Society of Petroleum Engineers (SPE).

In addition to gaining experience and competency through prior work experience, the Texas Board of Professional Engineers requires a minimum of fifteen
hours of continuing education annually, including at least one hour in the area of professional ethics, which Mr. Acuña fulfills. As part of his 2009 continuing education hours, Mr. Acuña attended over 34 hours of formalized
training and conferences including 10 hours dedicated to the subject of the definitions and disclosure guidelines contained in the United States Securities and Exchange Commission Title 17, Code of Federal Regulations, Modernization of Oil and Gas
Reporting, Final Rule released January 14, 2009 in the Federal Register. In 2009, Mr. Acuña taught various company reserves evaluation schools in Argentina, Bolivia, China, Spain, U.S.A and Venezuela. Mr. Acuña has
participated in various capacities in reserves conferences such as being a panelist a the 2008 Trinidad and Tobagos Petroleum Conference, delivering the reserves evaluation seminar during IAPG convention in Mendoza, Argentina in 2006 and
chairing the first Reserves Evaluation Conference in the Middle East in Dubai, U.A.E in 2006.

Based on his educational background,
professional training and 20 years of practical experience in petroleum engineering and the estimation and evaluation of petroleum reserves, Mr. Acuña has attained the professional qualifications as a Reserves Estimator and Reserves
Auditor set forth in Article III of the Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information promulgated by the Society of Petroleum Engineers as of February 19, 2007.



---

PETROLEUM RESERVES DEFINITIONS

As Adapted From:

RULE 4-10(a) of REGULATION S-X PART 210

UNITED STATES SECURITIES AND
EXCHANGE COMMISSION (SEC)

PREAMBLE

On January 14, 2009, the United States Securities and Exchange Commission (SEC) published the Modernization of Oil and Gas Reporting; Final Rule in the Federal Register of National
Archives and Records Administration (NARA). The Modernization of Oil and Gas Reporting; Final Rule includes revisions and additions to the definition section in Rule 4-10 of Regulation S-X, revisions and additions to the oil and gas
reporting requirements in Regulation S-K, and amends and codifies Industry Guide 2 in Regulation S-K. The Modernization of Oil and Gas Reporting; Final Rule, including all references to Regulation S-X and Regulation S-K, shall be
referred to herein collectively as the SEC Regulations. The SEC Regulations take effect for all filings made with the United States Securities and Exchange Commission as of December 31, 2009, or after January 1, 2010. Reference
should be made to the full text under Title 17, Code of Federal Regulations, Regulation S-X Part 210, Rule 4-10(a) for the complete definitions, as the following definitions, descriptions and explanations rely wholly or in part on excerpts from the
original document (direct passages excerpted from the aforementioned SEC document are denoted in italics herein).

Reserves
are those estimated remaining quantities of petroleum which are anticipated to be economically producible, as of a given date, from known accumulations under defined conditions. All reserve estimates involve some degree of uncertainty. The
uncertainty depends chiefly on the amount of reliable geologic and engineering data available at the time of the estimate and the interpretation of these data. The relative degree of uncertainty may be conveyed by placing reserves into one of two
principal classifications, either proved or unproved. Unproved reserves are less certain to be recovered than proved reserves and may be further sub-classified as probable and possible reserves to denote progressively increasing uncertainty in their
recoverability. Under the SEC Regulations as of December 31, 2009, or after January 1, 2010, a company may optionally disclose estimated quantities of probable or possible oil and gas reserves in documents publicly filed with the
Commission. The SEC Regulations continue to prohibit disclosure of estimates of oil and gas resources other than reserves and any estimated values of such resources in any document publicly filed with the Commission unless such information is
required to be disclosed in the document by foreign or state law as noted in §229.1202 Instruction to Item 1202.

Reserves estimates will generally be revised as additional geologic or engineering data become available or as economic conditions
change.

Reserves may be attributed to either natural energy or improved recovery methods. Improved recovery methods include
all methods for supplementing natural energy or altering natural forces in the reservoir to increase ultimate recovery. Examples of such methods are pressure maintenance, natural gas cycling, waterflooding, thermal methods, chemical flooding, and
the use of miscible and immiscible displacement fluids. Other improved recovery methods may be developed in the future as petroleum technology continues to evolve.



---

PETROLEUM RESERVES DEFINITIONS

Page 2



Reserves may be attributed to either conventional or unconventional petroleum
accumulations. Petroleum accumulations are considered as either conventional or unconventional based on the nature of their in-place characteristics, extraction method applied, or degree of processing prior to sale. Examples of unconventional
petroleum accumulations include coalbed or coalseam methane (CBM/CSM), basin-centered gas, shale gas, gas hydrates, natural bitumen and oil shale deposits. These unconventional accumulations may require specialized extraction technology and/or
significant processing prior to sale.

Reserves do not include quantities of petroleum being held in inventory.

Because of the differences in uncertainty, caution should be exercised when aggregating quantities of petroleum from different reserves
categories.

RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(26) defines reserves as follows:

Reserves.Reserves are estimated remaining quantities of oil and gas and related substances anticipated to be economically producible, as of a given date, by application of
development projects to known accumulations. In addition, there must exist, or there must be a reasonable expectation that there will exist, the legal right to produce or a revenue interest in the production, installed means of delivering oil and
gas or related substances to market, and all permits and financing required to implement the project.

Note to paragraph
(a)(26): Reserves should not be assigned to adjacent reservoirs isolated by major, potentially sealing, faults until those reservoirs are penetrated and evaluated as economically producible. Reserves should not be assigned to areas that are
clearly separated from a known accumulation by a non-productive reservoir (i.e., absence of reservoir, structurally low reservoir, or negative test results). Such areas may contain prospective resources (i.e., potentially recoverable
resources from undiscovered accumulations).

PROVED RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(22) defines proved oil and gas reserves as follows:

Proved oil and gas reserves.Proved oil and gas reserves are those quantities of oil and gas, which, by analysis of geoscience
and engineering data, can be estimated with reasonable certainty to be economically produciblefrom a given date forward, from known reservoirs, and under existing economic conditions, operating methods, and government regulationsprior to
the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. The project to extract the
hydrocarbons must have commenced or the operator must be reasonably certain that it will commence the project within a reasonable time.

(i) The area of the reservoir considered as proved includes:

(A) The
area identified by drilling and limited by fluid contacts, if any, and

(B) Adjacent undrilled portions of the reservoir
that can, with reasonable certainty, be judged to be continuous with it and to contain economically producible oil or gas on the basis of available geoscience and engineering data.

(ii) In the absence of data on fluid contacts, proved quantities in a reservoir are limited by the lowest known hydrocarbons (LKH) as
seen in a well penetration unless geoscience, engineering, or performance data and reliable technology establishes a lower contact with reasonable certainty.



---

PETROLEUM RESERVES DEFINITIONS

Page 3



PROVED RESERVES (SEC DEFINITIONS) CONTINUED

(iii) Where direct observation from well penetrations has defined a highest known oil (HKO) elevation and the potential exists for an
associated gas cap, proved oil reserves may be assigned in the structurally higher portions of the reservoir only if geoscience, engineering, or performance data and reliable technology establish the higher contact with reasonable certainty.
(iv) Reserves which can be produced economically through application of improved recovery techniques (including, but not limited to, fluid injection) are included in the proved classification when:

(A) Successful testing by a pilot project in an area of the reservoir with properties no more favorable than in the reservoir as a
whole, the operation of an installed program in the reservoir or an analogous reservoir, or other evidence using reliable technology establishes the reasonable certainty of the engineering analysis on which the project or program was based; and

(B) The project has been approved for development by all necessary parties and entities, including governmental
entities.

(v) Existing economic conditions include prices and costs at which economic producibility from a reservoir is
to be determined. The price shall be the average price during the 12-month period prior to the ending date of the period covered by the report, determined as an unweighted arithmetic average of the first-day-of-the-month price for each month within
such period, unless prices are defined by contractual arrangements, excluding escalations based upon future conditions.



---

RESERVES STATUS DEFINITIONS AND GUIDELINES

As Adapted From:

RULE 4-10(a) of REGULATION S-X PART 210

UNITED STATES SECURITIES AND
EXCHANGE COMMISSION (SEC)

and

PETROLEUM RESOURCES MANAGEMENT SYSTEM (SPE-PRMS)

Sponsored and Approved
by:

SOCIETY OF PETROLEUM ENGINEERS (SPE),

WORLD PETROLEUM COUNCIL (WPC)

AMERICAN ASSOCIATION OF PETROLEUM
GEOLOGISTS (AAPG)

SOCIETY OF PETROLEUM EVALUATION ENGINEERS (SPEE)

Reserves status categories define the development and producing status of wells and reservoirs. Reference should be made to Title 17,
Code of Federal Regulations, Regulation S-X Part 210, Rule 4-10(a) and the SPE-PRMS as the following reserves status definitions are based on excerpts from the original documents (direct passages excerpted from the aforementioned SEC and SPE-PRMS
documents are denoted in italics herein).

DEVELOPED RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(6) defines developed oil and gas reserves as follows:

Developed oil and gas reserves are reserves of any category that can be expected to be recovered:

(i) Through existing wells with existing equipment and operating methods or in which the cost of the required equipment is relatively
minor compared to the cost of a new well; and

(ii) Through installed extraction equipment and infrastructure
operational at the time of the reserves estimate if the extraction is by means not involving a well.

Developed Producing (SPE-PRMS
Definitions)

While not a requirement for disclosure under the SEC regulations, developed oil and gas reserves may be
further sub-classified according to the guidance contained in the SPE-PRMS as Producing or Non-Producing.

Developed
Producing Reserves

Developed Producing Reserves are expected to be recovered from completion intervals that
are open and producing at the time of the estimate.

Improved recovery reserves are considered producing only after the
improved recovery project is in operation.



---

RESERVES STATUS DEFINITIONS AND GUIDELINES

Page 2



Developed Non-Producing

Developed Non-Producing Reserves include shut-in and behind-pipe reserves.

Shut-In

Shut-in Reserves are expected to be recovered from:



| | (1) | completion intervals which are open at the time of the estimate but which have not yet started producing;
| | --- | ---------------------------------------------------------------------------------------------------------



| | (2) | wells which were shut-in for market conditions or pipeline connections; or
| | --- | --------------------------------------------------------------------------



| | (3) | wells not capable of production for mechanical reasons.
| | --- | -------------------------------------------------------

Behind-Pipe

Behind-pipe Reserves are expected to be
recovered from zones in existing wells which will require additional completion work or future re-completion prior to start of production.

In all cases, production can be initiated or restored with relatively low expenditure compared to the cost of drilling a new well.

UNDEVELOPED RESERVES (SEC DEFINITIONS)

Securities and Exchange
Commission Regulation S-X §210.4-10(a)(31) defines undeveloped oil and gas reserves as follows:

Undeveloped oil and
gas reserves are reserves of any category that are expected to be recovered from new wells on undrilled acreage, or from existing wells where a relatively major expenditure is required for recompletion.

(i) Reserves on undrilled acreage shall be limited to those directly offsetting development spacing areas that are reasonably certain
of production when drilled, unless evidence using reliable technology exists that establishes reasonable certainty of economic producibility at greater distances.

(ii) Undrilled locations can be classified as having undeveloped reserves only if a development plan has been adopted indicating that they are scheduled to be drilled within five years, unless the
specific circumstances, justify a longer time.

(iii) Under no circumstances shall estimates for undeveloped reserves be
attributable to any acreage for which an application of fluid injection or other improved recovery technique is contemplated, unless such techniques have been proved effective by actual projects in the same reservoir or an analogous reservoir, as
defined in paragraph (a)(2) of this section, or by other evidence using reliable technology establishing reasonable certainty.



---

Mitsui Oil Exploration Company Limited

Third Party Review of the

Process for Estimating Future Reserves

Attributable to Certain
Properties

Located Offshore Thailand

SEC Parameters

As of December 31, 2009



|                                             |  |                                   |  | 
|-------------------------------------------- |  | --------------------------------- |  | 
|                                             |  | /s/ Herman G. Acuña               |  | 
|                                             |  | Herman G. Acuña, P.E.             |  | 
|                                             |  | Texas PE License No. 92254        |  | 
|Managing Senior Vice PresidentInternational
|                                             |  |                                  
|                                             |  | RYDER SCOTT COMPANY, L.P.         |  | 
|                                             |  | TBPE Firm Registration No. F-1580 |  | 

[SEAL]



---

May 31, 2010

Mitsui Oil Exploration Company Limited (MOECO)

Hibiya Central Bldg. 11 Fl.

2-9 Nishi Shimbashi 1-Chome

Minato-Ku, Tokyo
105-0003

Japan

Gentlemen:

At the request of Mitsui Oil Exploration Company Limited (MOECO), Ryder Scott Company has conducted a review of the process,
methods and procedures followed by MOECO in their preparation of proved reserves, future production, and income as of December 31, 2009. The subject properties are located offshore in the Gulf of Thailand.

This report is based on our understanding of the definitions and disclosure guidelines contained in the United States Securities and
Exchange Commission Title 17, Code of Federal Regulations, Modernization of Oil and Gas Reporting, Final Rule released January 14, 2009, in the Federal Register (SEC regulations). An abridged version of the SEC reserves definitions from
210.4-10(a) entitled Petroleum Reserves Definitions is included as an attachment to this report. The conclusions of our third party study, completed on May 11, 2010, are discussed herein.

The conclusions discussed in this report, as of December 31, 2009, are related to hydrocarbon prices. The hydrocarbon prices used in
the preparation of this report are based on the average prices during the 12-month period prior to the ending date of the period covered in this report, determined as unweighted arithmetic averages of the prices in effect on the
first-day-of-the-month for each month within such period, unless prices were defined by contractual arrangements as required by the SEC regulations. Actual future prices may vary significantly from the prices required by SEC regulations; therefore,
the conclusions of our third party study may differ significantly from the discussion below.

MOECO has elected to represent
that Ryder Scott Company conducted this third party process review; accordingly, Ryder Scott Company has prepared this report for inclusion as an exhibit to the relevant registration statement or other commission filings by MOECO or
Mitsui & Co., Ltd., the parent company of MOECO.

Scope of 3rdParty Independent Review

At the request of MOECO, Ryder Scott Company conducted an independent review of the process followed by MOECO in their preparation of
proved reserves, future production, and income as of December 31, 2009. The review consisted of the following:



| | 1. | Review the methodology implemented by MOECO to verify the procedures used by Chevron, the operator, in the Pattani Field in the Gulf of Thailand to estimate proved
reserves and to render an opinion regarding the applicability of such method for SEC proved reserves booking purposes.
| | -- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 2. | Review the current implementation of MOECOs Corporate Reserves Reporting System (RRS).
| | -- | ---------------------------------------------------------------------------------------



---

Mitsui Oil Exploration Company Limited (MOECO)

May 31, 2010

Page 2



Ryder Scott Companys review was limited to the two points noted above and did not
involve an independent estimation of the proved reserves volumes or income thereof.

Ryder Scott Company was provided with
Chevrons Comprehensive Reserve Study (CRS) Report, which contains reserves summary sheets by platform and maps, and MOECOs utilization of this information in the preparation of the proved reserves estimates. Ryder Scott
Company also had access to the production data which is considered important since the reserves are estimated by analogy to existing producers.

During our investigations, no attempt was made to quantify or otherwise account for any accumulated gas production imbalances that may exist. It is our understanding that the gas volumes reported by MOECO
as proved reserves do not include gas consumed or flared in operations. Non-hydrocarbon and inert gas volumes have also been excluded by MOECO.

While it may reasonably be anticipated that the future prices received for the sale of production and the operating costs and other costs relating to such production may also increase or decrease from
existing levels, such changes were, in accordance with rules adopted by the SEC, omitted from consideration in making this evaluation.

Proved oil and gas reserves are those quantities of oil and gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from a
given date forward. However, most of the parameters that define the reserves of a reservoir cannot be measured directly, and must be estimated indirectly through geologic and reservoir engineering analysis and interpretations. Moreover, estimates of
reserves may increase or decrease as a result of future operations, effects of regulation by governmental agencies or geopolitical risks. As a result, the estimates of oil and gas reserves have an intrinsic uncertainty. The reserves discussed in
this report are, therefore, estimates only and should not be construed as being exact quantities. They may or may not be actually recovered, and if recovered, the revenues therefrom and the actual costs related thereto could be more or less than the
estimated amounts.

The conclusions reported herein are limited to the period prior to expiration of current contracts
providing the legal right to produce or a revenue interest in such production unless evidence indicates that contract renewal is reasonably certain. Furthermore, properties in the different countries may be subjected to significantly varying
contractual fiscal terms that affect the net revenue to MOECO for the production of these volumes. The prices and economic return received for these net volumes can vary significantly based on the terms of these contracts. Ryder Scott has not
conducted an exhaustive audit or verification of such contractual information as this was outside the scope of our assignment.

Ryder Scott did not evaluate country and geopolitical risks in the countries where MOECO operates or has interests. MOECOs
operations may be subject to various levels of governmental controls and regulations. These controls and regulations may include matters relating to land tenure, drilling, production practices, environmental protection, marketing and pricing
policies, royalties, various taxes and levies including income tax, and foreign trade and investment and are subject to change from time to time. Such changes in governmental regulations and policies may cause volumes of reserves actually recovered
and amounts of income actually received to differ significantly from the estimated quantities.

The conclusions presented
herein were based upon the reserves booking process review of the properties in which MOECO owns an interest; however, we have not made any field examination of the properties. No consideration was given in this report to potential environmental
liabilities that may exist, nor were any costs included for potential liability to restore and clean up damages, if any, caused by past operating practices.



---

Mitsui Oil Exploration Company Limited (MOECO)

May 31, 2010

Page 3



The properties for which Ryder Scott reviewed the reserves estimation process account
for a portion of MOECOs total net proved reserves as of December 31, 2009. Based on information provided by MOECO, the third party process review conducted by Ryder Scott addresses 35 percent of the total proved developed net liquid
hydrocarbon reserves, 36 percent of the total proved developed net gas reserves, 31 percent of the total proved undeveloped net liquid hydrocarbon reserves, and 37 percent of the total proved undeveloped net gas reserves of Mitsui & Co.,
Ltd. and its affiliated companies. The reserves included herein were estimated using deterministic methods.

Data, Methods and
Procedures

In performing our investigations, we have relied upon data furnished by MOECO with respect to property
interests owned, production data from examined wells, historical costs of operation and development, product prices, geological structural maps, etc. In general, the process review for the properties that we reviewed is based on data available
through December 31, 2009.

These data were accepted as authentic and sufficient for determining the reserves unless,
during the course of our examination, a matter of question came to our attention, in which case the data were not accepted until all questions were satisfactorily resolved.

As prescribed by the Society of Petroleum Engineers in Paragraph 2.2(f) of the Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information a reserves audit is defined as
the process of reviewing certain of the pertinent facts interpreted and assumptions made that have resulted in an estimate of reserves prepared by others and the rendering of an opinion about (1) the appropriateness of the methodologies
employed; (2) the adequacy and quality of the data relied upon; (3) the depth and thoroughness of the reserves estimation process; and (4) the classification of reserves appropriate to the relevant definitions used.

Ryder Scott Company visited MOECOs headquarters from April 12 to April 15, 2010. Prior to this visit, Ryder Scott Company
had received the CRS Report and production data. In general, the reserves were estimated by performance methods and performance analogies. Ryder Scott Company conducted a cursory review of the production data to confirm that the proposed analogies
were consistent with historical performance of the fields. The method consists of the development of type performance forecasts for the undeveloped locations. The study area has a very active drilling program and the type performance forecasts are
based on analogy to over 3,000 wells already drilled with approximately two thirds still active and producing. Ryder Scott conducted a cursory review of the performance of the wells and compared that performance to the type performance forecasts in
the CRS Report. Based on this information, it is our opinion, that the type performance forecasts are reasonable.

All
developed reserves are estimated by performance methods that include the extrapolation of historical trends. Similarly, 100 percent of the undeveloped reserves are based on performance analogies as previously described.

Ryder Scott Company also discussed with MOECO the implementation of their Reserves Reporting System or RRS to establish quality control
mechanisms in their reserves reporting process. This process was formalized in 2009 after two years of preparations. MOECOs RRS is centered on the Planning & Information System Division. Ryder Scott reviewed the implementation of the
Corporate RRS and found it appropriate within MOECOs E&P Division. Certain recommendations were made and implemented by MOECO to facilitate better communication between the E&P and Accounting Divisions.



---

Mitsui Oil Exploration Company Limited (MOECO)

May 31, 2010

Page 4



Summary of Ryder Scott Company Conclusions

It is our opinion that, in the aggregate, MOECOs estimates of future reserves for the reviewed properties were prepared in
accordance with generally accepted petroleum engineering and evaluation practice for the estimation of future reserves, and we found no bias in the utilization and analysis of data previously described in estimates for these properties.

Ryder Scott Company reviewed the implementation of the Corporate RRS and found it appropriate within the E&P Division. Ryder Scott
Company recommended that the Corporate RRS be expanded to contain clear instructions on what information needs to be transferred to the Accounting Division and who are the responsible parties at both the E&P and Accounting Divisions, to ensure
the proper generation of the economic test.

Standards of Independence and Professional Qualification

Ryder Scott is an independent petroleum engineering consulting firm that has been providing petroleum consulting services throughout the
world for over seventy years. Ryder Scott is employee owned and maintains offices in Houston, Texas; Denver, Colorado; and Calgary, Alberta, Canada. We have over eighty engineers and geoscientists on our permanent staff. By virtue of the size of our
firm and the large number of clients for which we provide services, no single client or job represents a material portion of our annual revenue. We do not serve as officers or directors of any publicly traded oil and gas company, and we are separate
and independent from the operating and investment decision-making process of our clients. This allows us to bring the highest level of independence and objectivity to each engagement for our services.

Ryder Scott actively participates in industry-related professional societies and organizes an annual public forum focused on the subject
of reserves evaluations and SEC regulations. Many of our staff have authored or co-authored technical papers on the subject of reserves related topics. We encourage our staff to maintain and enhance their professional skills by actively
participating in ongoing continuing education.

Prior to becoming an officer of the Company, Ryder Scott requires that staff
engineers and geoscientists have received professional accreditation in the form of a registered or certified professional engineers license or a registered or certified professional geoscientists license, or the equivalent thereof, from
an appropriate governmental authority or a recognized self-regulating professional organization.

We are independent petroleum
engineers with respect to MOECO. Neither we nor any of our employees have any interest in the subject properties, and neither the employment to do this work nor the compensation is contingent on our estimates of reserves for the properties which
were reviewed.

The conclusions presented in this report are the result of technical analysis conducted by teams of
geoscientists and engineers. The professional qualifications of the undersigned, the technical person primarily responsible for overseeing this project, is included as an attachment to this letter.



---

Mitsui Oil Exploration Company Limited (MOECO)

May 31, 2010

Page 5



Terms of Usage

The results of our third party review, presented in report form herein, were prepared in accordance with the disclosure requirements set forth in the SEC regulations and intended for public disclosure as
an exhibit in filings made with the SEC by Mitsui Oil Exploration Company Limited (MOECO) and Mitsui & Co., Ltd., the parent company of MOECO. We have provided our written consent to MOECO and Mitsui & Co., Ltd. for the references
to our name as well as to the references to the results of our third party review in filings made by MOECO and Mitsui & Co., Ltd. with the SEC.

We have provided MOECO and Mitsui & Co., Ltd. with a digital version of the original signed copy of this third party review report. In the event there are any differences between the digital
version included in filings made by MOECO and Mitsui & Co., Ltd. and the original signed third party review report, the original signed third party review report shall control and supersede the digital version.

The data and work papers used in the preparation of this audit report are available for examination by authorized parties in our offices.
Please contact us if we can be of further service.



Very truly yours,RYDER SCOTT COMPANY, L. P.TBPE Firm Registration No. F-1580/s/ Herman G. AcunaHerman G. Acuña, P.E.Texas P.E. License No. 92254Managing Senior Vice PresidentInternational


[SEAL]

HGA/sm



---

Professional Qualifications

Herman G. Acuña

The conclusions presented in this third party review report, issued on May 31, 2010, for Mitsui Oil Exploration Company Limited (MOECO), are the
result of technical analysis conducted by teams of geoscientists and engineers from Ryder Scott Company, L.P. Herman G. Acuña was the primary technical person responsible for overseeing the independent estimation of the reserves, future
production and income to render the audit conclusions of that report.

Mr. Acuña, an employee of Ryder Scott Company L.P. (Ryder
Scott) since 1997, is a Managing Senior International Vice President and serves as an Engineering Group Coordinator responsible for coordinating and supervising staff and consulting engineers of the company in ongoing reservoir evaluation studies
worldwide. Before joining Ryder Scott, Mr. Acuña served in a number of engineering positions with Exxon. For more information regarding Mr. Acuñas geographic and job specific experience, please refer to the Ryder Scott
Company website at www.ryderscott.com.

Mr. Acuña earned a Bachelor (Cum Laude) and a Masters (Magna Cum Laude) of Science
degrees in Petroleum Engineering from The University of Tulsa in 1987 and 1989 respectively. He is a registered Professional Engineer in the State of Texas, a member of the Association of International Petroleum Negotiators (AIPN) and the Society of
Petroleum Engineers (SPE).

In addition to gaining experience and competency through prior work experience, the Texas Board of Professional
Engineers requires a minimum of fifteen hours of continuing education annually, including at least one hour in the area of professional ethics, which Mr. Acuña fulfills. As part of his 2009 continuing education hours,
Mr. Acuña attended over 34 hours of formalized training and conferences including 10 hours dedicated to the subject of the definitions and disclosure guidelines contained in the United States Securities and Exchange Commission Title 17,
Code of Federal Regulations, Modernization of Oil and Gas Reporting, Final Rule released January 14, 2009 in the Federal Register. In 2009, Mr. Acuña taught various company reserves evaluation schools in Argentina, Bolivia, China,
Spain, U.S.A and Venezuela. Mr. Acuña has participated in various capacities in reserves conferences such as being a panelist a the 2008 Trinidad and Tobagos Petroleum Conference, delivering the reserves evaluation seminar during
IAPG convention in Mendoza, Argentina in 2006 and chairing the first Reserves Evaluation Conference in the Middle East in Dubai, U.A.E in 2006.

Based on his educational background, professional training and 20 years of practical experience in petroleum engineering and the estimation and
evaluation of petroleum reserves, Mr. Acuña has attained the professional qualifications as a Reserves Estimator and Reserves Auditor set forth in Article III of the Standards Pertaining to the Estimating and Auditing of Oil and
Gas Reserves Information promulgated by the Society of Petroleum Engineers as of February 19, 2007.



---

PETROLEUM RESERVES DEFINITIONS

As Adapted From:

RULE 4-10(a) of REGULATION S-X PART 210

UNITED STATES SECURITIES AND
EXCHANGE COMMISSION (SEC)

PREAMBLE

On January 14, 2009, the United States Securities and Exchange Commission (SEC) published the Modernization of Oil and Gas Reporting; Final Rule in the Federal Register of National
Archives and Records Administration (NARA). The Modernization of Oil and Gas Reporting; Final Rule includes revisions and additions to the definition section in Rule 4-10 of Regulation S-X, revisions and additions to the oil and gas
reporting requirements in Regulation S-K, and amends and codifies Industry Guide 2 in Regulation S-K. The Modernization of Oil and Gas Reporting; Final Rule, including all references to Regulation S-X and Regulation S-K, shall be
referred to herein collectively as the SEC Regulations. The SEC Regulations take effect for all filings made with the United States Securities and Exchange Commission as of December 31, 2009, or after January 1, 2010. Reference
should be made to the full text under Title 17, Code of Federal Regulations, Regulation S-X Part 210, Rule 4-10(a) for the complete definitions, as the following definitions, descriptions and explanations rely wholly or in part on excerpts from the
original document (direct passages excerpted from the aforementioned SEC document are denoted in italics herein).

Reserves
are those estimated remaining quantities of petroleum which are anticipated to be economically producible, as of a given date, from known accumulations under defined conditions. All reserve estimates involve some degree of uncertainty. The
uncertainty depends chiefly on the amount of reliable geologic and engineering data available at the time of the estimate and the interpretation of these data. The relative degree of uncertainty may be conveyed by placing reserves into one of two
principal classifications, either proved or unproved. Unproved reserves are less certain to be recovered than proved reserves and may be further sub-classified as probable and possible reserves to denote progressively increasing uncertainty in their
recoverability. Under the SEC Regulations as of December 31, 2009, or after January 1, 2010, a company may optionally disclose estimated quantities of probable or possible oil and gas reserves in documents publicly filed with the
Commission. The SEC Regulations continue to prohibit disclosure of estimates of oil and gas resources other than reserves and any estimated values of such resources in any document publicly filed with the Commission unless such information is
required to be disclosed in the document by foreign or state law as noted in §229.1202 Instruction to Item 1202.

Reserves estimates will generally be revised as additional geologic or engineering data become available or as economic conditions
change.

Reserves may be attributed to either natural energy or improved recovery methods. Improved recovery methods include
all methods for supplementing natural energy or altering natural forces in the reservoir to increase ultimate recovery. Examples of such methods are pressure maintenance, natural gas cycling, waterflooding, thermal methods, chemical flooding, and
the use of miscible and immiscible displacement fluids. Other improved recovery methods may be developed in the future as petroleum technology continues to evolve.

Reserves may be attributed to either conventional or unconventional petroleum accumulations. Petroleum accumulations are considered as either conventional or unconventional based on the nature of their
in-place characteristics, extraction method applied, or degree of processing prior to sale. Examples of unconventional petroleum accumulations include coalbed or coalseam methane (CBM/CSM), basin-centered gas, shale gas, gas hydrates, natural
bitumen and oil shale deposits.



---

PETROLEUM RESERVES DEFINITIONS

Page 2



These unconventional accumulations may require specialized extraction technology and/or significant
processing prior to sale.

Reserves do not include quantities of petroleum being held in inventory.

Because of the differences in uncertainty, caution should be exercised when aggregating quantities of petroleum from different reserves
categories.

RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(26) defines reserves as follows:

Reserves.Reserves are estimated remaining quantities of oil and gas and related substances anticipated to be economically producible, as of a given date, by application of
development projects to known accumulations. In addition, there must exist, or there must be a reasonable expectation that there will exist, the legal right to produce or a revenue interest in the production, installed means of delivering oil and
gas or related substances to market, and all permits and financing required to implement the project.

Note to paragraph
(a)(26): Reserves should not be assigned to adjacent reservoirs isolated by major, potentially sealing, faults until those reservoirs are penetrated and evaluated as economically producible. Reserves should not be assigned to areas that are
clearly separated from a known accumulation by a non-productive reservoir (i.e., absence of reservoir, structurally low reservoir, or negative test results). Such areas may contain prospective resources (i.e., potentially recoverable
resources from undiscovered accumulations).

PROVED RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(22) defines proved oil and gas reserves as follows:

Proved oil and gas reserves.Proved oil and gas reserves are those quantities of oil and gas, which, by analysis of geoscience
and engineering data, can be estimated with reasonable certainty to be economically produciblefrom a given date forward, from known reservoirs, and under existing economic conditions, operating methods, and government regulationsprior to
the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. The project to extract the
hydrocarbons must have commenced or the operator must be reasonably certain that it will commence the project within a reasonable time.

(i) The area of the reservoir considered as proved includes:

(A) The
area identified by drilling and limited by fluid contacts, if any, and

(B) Adjacent undrilled portions of the reservoir
that can, with reasonable certainty, be judged to be continuous with it and to contain economically producible oil or gas on the basis of available geoscience and engineering data.

(ii) In the absence of data on fluid contacts, proved quantities in a reservoir are limited by the lowest known hydrocarbons (LKH) as
seen in a well penetration unless geoscience, engineering, or performance data and reliable technology establishes a lower contact with reasonable certainty.



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PETROLEUM RESERVES DEFINITIONS

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PROVED RESERVES (SEC DEFINITIONS) CONTINUED

(iii) Where direct observation from well penetrations has defined a highest known oil (HKO) elevation and the potential exists for an
associated gas cap, proved oil reserves may be assigned in the structurally higher portions of the reservoir only if geoscience, engineering, or performance data and reliable technology establish the higher contact with reasonable certainty.

(iv) Reserves which can be produced economically through application of improved recovery techniques (including, but not
limited to, fluid injection) are included in the proved classification when:

(A) Successful testing by a pilot project
in an area of the reservoir with properties no more favorable than in the reservoir as a whole, the operation of an installed program in the reservoir or an analogous reservoir, or other evidence using reliable technology establishes the reasonable
certainty of the engineering analysis on which the project or program was based; and

(B) The project has been approved
for development by all necessary parties and entities, including governmental entities.

(v) Existing economic
conditions include prices and costs at which economic producibility from a reservoir is to be determined. The price shall be the average price during the 12-month period prior to the ending date of the period covered by the report, determined as an
unweighted arithmetic average of the first-day-of-the-month price for each month within such period, unless prices are defined by contractual arrangements, excluding escalations based upon future conditions.

PROBABLE RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(18) defines probable oil and gas reserves as follows:

Probable reserves.Probable reserves are those additional reserves that are less certain to be recovered than proved reserves but which, together with proved reserves, are as
likely as not to be recovered.

(i) When deterministic methods are used, it is as likely as not that actual remaining
quantities recovered will exceed the sum of estimated proved plus probable reserves. When probabilistic methods are used, there should be at least a 50% probability that the actual quantities recovered will equal or exceed the proved plus probable
reserves estimates.

(ii) Probable reserves may be assigned to areas of a reservoir adjacent to proved reserves where
data control or interpretations of available data are less certain, even if the interpreted reservoir continuity of structure or productivity does not meet the reasonable certainty criterion. Probable reserves may be assigned to areas that are
structurally higher than the proved area if these areas are in communication with the proved reservoir.

(iii) Probable
reserves estimates also include potential incremental quantities associated with a greater percentage recovery of the hydrocarbons in place than assumed for proved reserves.

(iv) See also guidelines in paragraphs (a)(17)(iv) and (a)(17)(vi) of this section.



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PETROLEUM RESERVES DEFINITIONS

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POSSIBLE RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(17) defines possible oil and gas reserves as follows:

Possible reserves.Possible reserves are those additional reserves that are less certain to be recovered than probable reserves.

(i) When deterministic methods are used, the total quantities ultimately recovered from a project have a low
probability of exceeding proved plus probable plus possible reserves. When probabilistic methods are used, there should be at least a 10% probability that the total quantities ultimately recovered will equal or exceed the proved plus probable plus
possible reserves estimates.

(ii) Possible reserves may be assigned to areas of a reservoir adjacent to probable
reserves where data control and interpretations of available data are progressively less certain. Frequently, this will be in areas where geoscience and engineering data are unable to define clearly the area and vertical limits of commercial
production from the reservoir by a defined project.

(iii) Possible reserves also include incremental quantities
associated with a greater percentage recovery of the hydrocarbons in place than the recovery quantities assumed for probable reserves.

(iv) The proved plus probable and proved plus probable plus possible reserves estimates must be based on reasonable alternative technical and commercial interpretations within the reservoir or subject
project that are clearly documented, including comparisons to results in successful similar projects.

(v) Possible
reserves may be assigned where geoscience and engineering data identify directly adjacent portions of a reservoir within the same accumulation that may be separated from proved areas by faults with displacement less than formation thickness or other
geological discontinuities and that have not been penetrated by a wellbore, and the registrant believes that such adjacent portions are in communication with the known (proved) reservoir. Possible reserves may be assigned to areas that are
structurally higher or lower than the proved area if these areas are in communication with the proved reservoir.

(vi)
Pursuant to paragraph (a)(22)(iii) of this section, where direct observation has defined a highest known oil (HKO) elevation and the potential exists for an associated gas cap, proved oil reserves should be assigned in the structurally higher
portions of the reservoir above the HKO only if the higher contact can be established with reasonable certainty through reliable technology. Portions of the reservoir that do not meet this reasonable certainty criterion may be assigned as probable
and possible oil or gas based on reservoir fluid properties and pressure gradient interpretations.



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RESERVES STATUS DEFINITIONS AND GUIDELINES

As Adapted From:

RULE 4-10(a) of REGULATION S-X PART 210

UNITED STATES SECURITIES AND
EXCHANGE COMMISSION (SEC)

and

PETROLEUM RESOURCES MANAGEMENT SYSTEM (SPE-PRMS)

Sponsored and Approved
by:

SOCIETY OF PETROLEUM ENGINEERS (SPE),

WORLD PETROLEUM COUNCIL (WPC)

AMERICAN ASSOCIATION OF PETROLEUM
GEOLOGISTS (AAPG)

SOCIETY OF PETROLEUM EVALUATION ENGINEERS (SPEE)

Reserves status categories define the development and producing status of wells and reservoirs. Reference should be made to Title 17,
Code of Federal Regulations, Regulation S-X Part 210, Rule 4-10(a) and the SPE-PRMS as the following reserves status definitions are based on excerpts from the original documents (direct passages excerpted from the aforementioned SEC and SPE-PRMS
documents are denoted in italics herein).

DEVELOPED RESERVES (SEC DEFINITIONS)

Securities and Exchange Commission Regulation S-X §210.4-10(a)(6) defines developed oil and gas reserves as follows:

Developed oil and gas reserves are reserves of any category that can be expected to be recovered:

(i) Through existing wells with existing equipment and operating methods or in which the cost of the required equipment is relatively
minor compared to the cost of a new well; and

(ii) Through installed extraction equipment and infrastructure
operational at the time of the reserves estimate if the extraction is by means not involving a well.

Developed Producing (SPE-PRMS
Definitions)

While not a requirement for disclosure under the SEC regulations, developed oil and gas reserves may be
further sub-classified according to the guidance contained in the SPE-PRMS as Producing or Non-Producing.

Developed
Producing Reserves

Developed Producing Reserves are expected to be recovered from completion intervals that are
open and producing at the time of the estimate.

Improved recovery reserves are considered producing only after the
improved recovery project is in operation.



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RESERVES STATUS DEFINITIONS AND GUIDELINES

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Developed Non-Producing

Developed Non-Producing Reserves include shut-in and behind-pipe reserves.

Shut-In

Shut-in Reserves are expected to be recovered from:



| | (1) | completion intervals which are open at the time of the estimate but which have not yet started producing;
| | --- | ---------------------------------------------------------------------------------------------------------



| | (2) | wells which were shut-in for market conditions or pipeline connections; or
| | --- | --------------------------------------------------------------------------



| | (3) | wells not capable of production for mechanical reasons.
| | --- | -------------------------------------------------------

Behind-Pipe

Behind-pipe Reserves are expected to be
recovered from zones in existing wells which will require additional completion work or future re-completion prior to start of production.

In all cases, production can be initiated or restored with relatively low expenditure compared to the cost of drilling a new well.

UNDEVELOPED RESERVES (SEC DEFINITIONS)

Securities and Exchange
Commission Regulation S-X §210.4-10(a)(31) defines undeveloped oil and gas reserves as follows:

Undeveloped oil and
gas reserves are reserves of any category that are expected to be recovered from new wells on undrilled acreage, or from existing wells where a relatively major expenditure is required for recompletion.

(i) Reserves on undrilled acreage shall be limited to those directly offsetting development spacing areas that are reasonably certain
of production when drilled, unless evidence using reliable technology exists that establishes reasonable certainty of economic producibility at greater distances.

(ii) Undrilled locations can be classified as having undeveloped reserves only if a development plan has been adopted indicating that they are scheduled to be drilled within five years, unless the
specific circumstances, justify a longer time.

(iii) Under no circumstances shall estimates for undeveloped reserves be
attributable to any acreage for which an application of fluid injection or other improved recovery technique is contemplated, unless such techniques have been proved effective by actual projects in the same reservoir or an analogous reservoir, as
defined in paragraph (a)(2) of this section, or by other evidence using reliable technology establishing reasonable certainty.