Exhibit 99

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

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

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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:

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.

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

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.