Exhibit 99



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February 13, 2015

Corporate Trust Division

Trustee, BP Prudhoe Bay Royalty Trust

The Bank of New York Mellon Trust Company, N.A.

919
Congress Avenue, Suite 500

Austin, Texas 78701

Attn:
Ms. Sarah Newell, Vice President



| | Re: | Estimates of Proved Reserves,
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| |  | Future Production Rates, and
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| |  | Future Net Revenues for the
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| |  | BP Prudhoe Bay Royalty Trust
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| |  | As of December 31, 2014
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Gentlemen:

This letter report is a summary of investigations performed in accordance with the Miller and Lents, Ltd. (MLL) engagement by you as described
in Section 4.8(d) of the Overriding Royalty Conveyance dated February 27, 1989, between BP Exploration (Alaska) Inc. and The Standard Oil Company. The purpose of MLLs review was to determine that the procedures and methods used by BP
Exploration (Alaska) Inc. are effective and in accordance with the definitions contained in the Securities and Exchange Commission Regulation S-X, Rule 4-10(a). The investigations included reviews of the estimates of Proved Reserves and production
rate forecasts of oil and condensate made by BP Exploration (Alaska) Inc. attributable to the BP Prudhoe Bay Royalty Trust (Trust) as of December 31, 2014. Additionally, MLL reviewed calculations of the resulting Estimated Future Net Revenues
and Present Value of Estimated Future Net Revenues attributable to the BP Prudhoe Bay Royalty Trust.

Under the terms of an Issues
Resolution Agreement entered into by the Prudhoe Bay Unit owners in October 1990, produced condensate from the Gas Cap Initial Participating Area (Gas Cap IPA) were allocated to the Gas Cap IPA until a cumulative limit of 1,175 million barrels
was reached. This cumulative limit was reached in June 2014. Beginning at that time and continuing thereafter, that condensate is allocated to the Oil Rim Participating Area. MLLs review covers 100 percent of reserves and revenues attributable
to the BP Prudhoe Bay Royalty Trust.

The estimates and calculations reviewed were summarized in the report prepared by BP Exploration
(Alaska) Inc. and transmitted with a cover letter dated February 6, 2015, addressed to Ms. Sarah Newell of The Bank of New York Mellon Trust Company, N.A. and signed by Mr. Mark Wichman. Reviews were also performed by MLL during
this year or in previous years of (1) the procedures for estimating and documenting Proved Reserves, (2) the estimates of in-place reservoir volumes, (3) the estimates of recovery



TWO HOUSTON CENTER909 FANNIN STREET, SUITE 1300HOUSTON, TEXAS
77010

TELEPHONE 713-651-9455TELEFAX 713-654-9914email: mail@millerandlents.com



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|The Bank of New York Mellon Trust Company, N.A.
Trustee, BP Prudhoe Bay Royalty Trust |  | February 13, 2015
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factors and production profiles for the various areas, pay zones, projects, and recovery processes that are included in the estimate of Proved Reserves, (4) the production strategy and
procedures for implementing that strategy, (5) the sufficiency of the data available for making estimates of Proved Reserves and production profiles, and (6) pertinent provisions of the Prudhoe Bay Unit Operating Agreement, the Issues
Resolution Agreement, the Overriding Royalty Conveyance, the Trust Conveyance, the BP Prudhoe Bay Royalty Trust Agreement, and other related documents referenced in the Form F-3 Registration Statement filed with the Securities and Exchange
Commission (SEC) on August 7, 1989 by BP Exploration (Alaska) Inc.

Proved Reserves were estimated by BP Exploration (Alaska) Inc. in
accordance with the definitions contained in Securities and Exchange Commission Regulation S-X, Rule 4-10(a). Estimated Future Net Revenues and Present Value of Estimated Future Net Revenues are not intended and should not be interpreted to
represent fair market values for the estimated reserves.

The Prudhoe Bay (Permo-Triassic) Reservoir is defined in the Prudhoe Bay Unit
Operating Agreement. The Prudhoe Bay Unit is an oil and gas unit situated on the North Slope of Alaska. The BP Prudhoe Bay Royalty Trust is entitled to a royalty payment on 16.4246 percent of the first 90,000 barrels of the actual average daily
net production of oil and condensate for each calendar quarter from the BP Exploration (Alaska) Inc. working interest as defined in the Overriding Royalty Conveyance. The payment amount depends upon the per barrel Royalty that in turn depends upon
the West Texas Intermediate Price, the Chargeable Costs, the Cost Adjustment Factor, and Production Taxes, all of which are defined in the Overriding Royalty Conveyance. Changes to the Production Tax beginning January 1, 2014, were legislated
by the State of Alaska and are incorporated herein. Barrel as used herein means Stock Tank Barrel as defined in the Overriding Royalty Conveyance.

Payments received by the Trust are based exclusively on a percentage of the first 90,000 barrels of the average actual daily net production of
crude oil from the leases subject to the Overriding Royalty Conveyance. There is no relationship between any delivery commitments of BP Exploration (Alaska) and the other owners of the working interests in the Prudhoe Bay Field and the
Trusts entitlement to the prescribed royalty payments. The Trust does not directly or indirectly own any working interests in wells, operations, or acreage.

MLLs reviews do not constitute independent estimates of the reserves and annual production rate forecasts for the areas, pay zones,
projects, and recovery processes examined. MLL relied upon the accuracy and completeness of information provided by BP Exploration (Alaska) Inc. with respect to pertinent ownership interests and various other historical, accounting, engineering, and
geological data. MLL employed all methods, procedures, and assumptions considered necessary in utilizing the data provided to prepare this report.

As a result of our cumulative reviews, based on the foregoing, MLL concludes that:



| | 1. | A large body of basic data and detailed analyses are available and were used in making the estimates. In MLLs judgment, the quantity and quality
of currently available data on reservoir boundaries, original fluid contacts, and reservoir rock and fluid properties are
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|The Bank of New York Mellon Trust Company, N.A.
Trustee, BP Prudhoe Bay Royalty Trust |  | February 13, 2015
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| | sufficient to indicate that any future revisions to the estimates of total original in-place volumes should be minor. Furthermore, the data and analyses on recovery factors and future production
rates are sufficient to support the Proved Reserves estimates.
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| | 2. | Proved Reserves were estimated generally by extrapolation of well-established historical production performance trends and/or were supported by other geologic and engineering studies. Where sufficient performance data
did not exist, reserves were estimated by volumetric calculations, simulations, or by analogy to similar producing areas of the field. The methods and procedures employed to accumulate and evaluate the necessary information and to estimate,
document, and reconcile reserves, annual production rate forecasts, and future net revenues are effective and appropriate.
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| | 3. | Based on MLLs limited independent tests of the computations of reserves, production flowstreams, and future net revenues, such computations were performed in accordance with the methods and procedures described to
us and conform to the relevant SEC definitions.
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| | 4. | The estimated net remaining Proved Reserves attributable to the BP Prudhoe Bay Royalty Trust as of December 31, 2014 of 65.055 million barrels of oil are, in the aggregate, reasonable. Of the
65.055 million barrels of total Proved Reserves, 61.856 million barrels are Proved Developed Reserves, and 3.199 million barrels are Proved Undeveloped Reserves.
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| | 5. | The 2014 average West Texas Intermediate Price of $94.99 per barrel, applicable under current SEC regulations, represents the 12-month average of the first-day-of-the-month price for each month within the 12-month
period prior to December 31, 2014. Based on this price, other economic parameters as prescribed by the Overriding Royalty Conveyance, and utilizing the specified procedures outlined in Financial Accounting Standards Board Accounting Standards
Codification 932, Extractive Activities  Oil and Gas, BP Exploration (Alaska) Inc. calculated that as of December 31, 2014 production of the Proved Reserves will result in Estimated Future Net Revenues of $2,106.7 million and
Present Value of Estimated Future Net Revenues of $1,402.5 million to the BP Prudhoe Bay Royalty Trust. These estimates are reasonable.
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| | 6. | As a consequence of the natural production decline and the downtime required for ongoing infrastructure and other improvements, BP Exploration (Alaska) Inc.s net production of oil from Proved Reserves attributable
to the Trust was less than 90,000 barrels per day on an annual average basis in 2014. BP Exploration (Alaska) Inc. expects that its net production of oil from Proved Reserves attributable to the Trust will be less than 90,000 barrels per day on an
average basis for most future years. The BP Exploration (Alaska) Inc. projection of its future net production of oil is reasonable.
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| | 7. | Production attributable to the BP Prudhoe Bay Royalty Trust will decline with the BP Exploration (Alaska) Inc. production. However, the per barrel
Royalty will not have a positive value if the West Texas Intermediate Price is less than the sum of the per barrel
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|The Bank of New York Mellon Trust Company, N.A.
Trustee, BP Prudhoe Bay Royalty Trust |  | February 13, 2015
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| | Chargeable Costs and per barrel Production Taxes, appropriately adjusted in accordance with the Overriding Royalty Conveyance. Under such circumstances, average daily production attributable to
the BP Prudhoe Bay Royalty Trust will have no value and therefore will not contribute to the reserves regardless of BP Exploration (Alaska) Inc.s net production level.
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| | 8. | Based on the SEC-defined 12-month average West Texas Intermediate Price of $94.99 per barrel and Production Taxes and Adjusted Chargeable Costs as prescribed by the Overriding Royalty Conveyance, the projection that
royalty payments will continue through the year 2028 is reasonable. For the economic conditions and production forecast as of December 31, 2014 per barrel Royalty will be zero following the year 2028. Therefore, no reserves are currently
attributed to the BP Prudhoe Bay Royalty Trust after that date. The cessation of production date forecasted by BP Exploration (Alaska) Inc. exceeds the life of the Prudhoe Bay Royalty Trust.
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| | 9. | Even if expected reservoir performance does not change, the estimated reserves, economic life, and future net revenues attributable to the BP Prudhoe Bay Royalty Trust may change significantly in the future. This may
result from sustained periods of change in the West Texas Intermediate Price, the Production Tax, or from changes in other prescribed variables utilized in calculations defined by the Overriding Royalty Conveyance.
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Estimates of ultimate and remaining reserves and production scheduling depend upon assumptions regarding expansion or implementation of
alternative projects or development programs and upon strategies for production optimization. BP Exploration (Alaska) Inc. has continual reservoir management, surveillance, and planning efforts dedicated to (1) gathering new information,
(2) improving the accuracy of its reserves and production capacity estimates, (3) recognizing and exploiting new opportunities, (4) anticipating potential problems and taking corrective actions, and (5) identifying, selecting,
and implementing optimum recovery program and cost reduction alternatives. Given this significant effort and ever-changing economic conditions, estimates of reserves and production profiles will change periodically.

The current estimate of Proved Reserves includes volumes of Proved Undeveloped reserves that are part of ongoing development activities for
which BP Exploration (Alaska) Inc. has a historical track record of completing comparable projects. Net Proved Undeveloped Reserves attributable to the Trust were reduced by approximately 3.599 million barrels during 2014 as a result of
forecast revisions and capital activities including drilling, facility upgrades, and well treatments. In all cases, the volumes are

being
progressed as part of an adopted development plan that calls for drilling of wells over an extended period of time given the magnitude of the development. There were no contributions to Proved Undeveloped Reserves from extensions or discoveries
during 2014.

Future projects, development programs, or operating strategies different from those assumed in the current estimates may
change future estimates and affect recoveries. However, because several complementary and alternative projects are being considered for recovery of the remaining oil in the reservoir, a decision not to implement a currently planned project may allow
scope expansion or implementation of another project, thereby increasing the overall likelihood of recovering the reserves.



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|The Bank of New York Mellon Trust Company, N.A.
Trustee, BP Prudhoe Bay Royalty Trust |  | February 13, 2015
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Future production rates will be controlled by facilities limitations and upsets, well
downtime, and the effectiveness of programs to optimize production and costs. Additional drilling, workovers, facilities modifications, new recovery projects, and programs for production enhancement and optimization are expected to mitigate but not
eliminate the decline in gross oil production capacity.

In making its future production rate forecasts, BP Exploration (Alaska) Inc.
provided for anticipated downtime and planned facilities upsets. Although allowances for unplanned upsets are also considered in the estimates, the studies do not provide for any impediments to crude oil production as a consequence of major
disruptions.

Under current economic conditions, gas from the Alaskan North Slope, except for minor volumes, cannot be marketed
commercially. Oil recovery is expected to be greater as a result of continued reinjection of produced gas than the recoveries would be if major volumes of produced gas were being sold. No major gas sale is assumed in the current estimates. In the
event that major gas sales are initiated, likely to supply a major liquefied natural gas (LNG) project under consideration, ultimate oil recovery may be reduced from the current estimate unless recovery projects other than those included in the
current estimate are implemented.

Large volumes of natural gas liquids (NGLs) are likely to be produced and marketed in the future
whether or not major gas sales become viable. NGL reserves are not included in the estimates cited herein. The BP Prudhoe Bay Royalty Trust is not entitled to royalty payments from production or sales of natural gas, LNG, or NGLs.

The evaluations presented in this report, with the exceptions of those parameters specified by others, reflect MLLs informed judgments
and are subject to the inherent uncertainties associated with interpretation of geological, geophysical, and engineering information. These uncertainties include, but are not limited to the (1) utilization of analogous or indirect data and
(2) application of professional judgment. At this time, MLL and BP Exploration (Alaska) Inc. are not aware of any existing or pending federal or state regulations that would materially affect the ability of BP Exploration (Alaska) Inc. to
recover the estimated reserves in the Prudhoe Bay Field. Government policies and market conditions different from those reflected in this study or disruption of existing transportation routes or facilities may cause (1) the total quantity of
oil or condensate to be recovered, (2) actual production rates, (3) prices received, or (4) operating and capital costs to vary from those reviewed in this report.

Miller and Lents, Ltd. was founded in 1948, offering services and expertise in many phases of the oil and gas industry. The firm is registered
with the Texas Board of Professional Engineers. The engineering staff members assigned to the BP Prudhoe Bay Royalty Trust project are all university graduates, with degrees in petroleum or chemical engineering and/or advanced degrees in petroleum
or chemical engineering. Assigned staff members include licensed professional engineers with over 25 years of diversified experience, including at least 10 years of experience with the BP Prudhoe Bay Royalty Trust.

Miller and Lents, Ltd. is an independent oil and gas consulting firm. No director, officer, or key employee of Miller and Lents, Ltd. has any
financial ownership in the BP Prudhoe Bay Royalty Trust, BP Exploration (Alaska) Inc. or its parent or any related companies. Our fee is not contingent upon the results of



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|The Bank of New York Mellon Trust Company, N.A.
Trustee, BP Prudhoe Bay Royalty Trust |  | February 13, 2015
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our work or report, and we have not performed other services for BP Exploration (Alaska) Inc. or the BP Prudhoe Bay Royalty Trust that would affect our objectivity. Miller and Lents, Ltd. hereby
grants consent for use of this letter, in its entirety, in the BP Prudhoe Bay Royalty Trusts SEC Form 10-K annual report filing for the fiscal year ended December 31, 2014.



Very truly yours,MILLER AND LENTS, LTD.Texas Registered Engineering Firm No. F-1442By

/s/ William P. KozaWilliam P. Koza, P.E.Senior ConsultantBy

/s/ Robert J. OberstRobert J. Oberst, P.E.President