Exhibit 99
DeGolyer and
MacNaughton
5001
Spring Valley Road
Suite 800
Eas t
Dallas,
Texas 75244
February 18, 2020
ConocoPhillips
925 N. Eldridge Parkway
Houston, Texas 77079
Re: SEC Process
Review
Ladies and Gentlemen:
Pursuant
to your request, DeGolyer and MacNaughton
has performed a process review of the
processes and
controls used within
ConocoPhillips in preparing
its internal estimates
of proved
reserves, as
of December 31,
2019. This process review, which
is contemplated by Item 1202
(a)(8) of
Regulation S–K of
the United States Securities and Exchange
Commission (SEC), has been performed
specifically to address the adequacy and effectiveness of ConocoPhillips’ internal
processes and controls
relative to
its estimation of proved reserves in compliance with Rules
4–10(a) (1)–(32) of
Regulation S–
X of the SEC.
DeGolyer and
MacNaughton has participated
as an independent
member of the internal
ConocoPhillips Reserves
Compliance Assessment Team
in reviews and
discussions with each
of the
relevant ConocoPhillips
business units relative
to SEC proved
reserves estimation. DeGolyer and
MacNaughton has participated in the review of all major
fields in all countries in which ConocoPhillips
has proved
reserves worldwide, which
ConocoPhillips has indicated
represents over 90
percent of its
estimated total
proved reserves as of December 31,
2019.
The reviews
with ConocoPhillips’ technical
staff involved presentations
and discussions of a)
basic reservoir data, including seismic data, well-log
data, pressure and production tests, core analysis,
pressure-volume-temperature data,
and production history,
b) technical methods
employed in SEC
proved reserves
estimation, including performance
analysis, geology, mapping,
and volumetric
estimates, c)
economic analysis, and
d) commercial assessment,
including the legal
basis for the
interest in the
reserves, primarily related to lease agreements and other petroleum license agreements,
such as concession and production sharing agreements.
ConocoPhillips
February 18, 2020
Page 2 of 2
A field examination of the properties was not
considered necessary for the purposes of this
review of ConocoPhillips’ processes and controls.
It
is DeGolyer and
MacNaughton’s opinion that
ConocoPhillips’ estimates of proved reserves
for the properties reviewed
were prepared by the use of
recognized geologic and engineering methods
generally accepted
by the petroleum
industry. The method
or combination of
methods used in the
analysis of each reservoir was tempered
by ConocoPhillips’ experience with similar reservoirs, stage of
development, quality
and completeness of
basic data, and
production history. It
is DeGolyer and
MacNaughton’s opinion
that the general
processes and controls
employed by ConocoPhillips in
estimating its December 31, 2019,
proved reserves for the properties reviewed
are in accordance with
the SEC reserves
definitions.
This process
review of ConocoPhillips’
procedures and methods
does not constitute
a review,
study, or
independent audit of ConocoPhillips’ estimated proved reserves and
corresponding future net
revenues.
This process review is not intended
to indicate that DeGolyer and MacNaughton
is offering
any opinion as to the reasonableness of the reserves estimates reported by
ConocoPhillips.
DeGolyer and MacNaughton is an
independent petroleum engineering consulting firm that has
been providing petroleum
consulting services throughout the world since
1936. Neither DeGolyer and
MacNaughton
nor any employee who participated in
this project has any financial interest, including
stock ownership,
in ConocoPhillips. DeGolyer
and MacNaughton’s fees
were not contingent
on the
results of its
evaluation.
Very truly yours,
/s/ DeGolyer and MacNaughton
DeGOLYER and MacNAUGHTON
Texas Registered Engineering Firm F-716
/s/ Charles F. Boyette
Charles F.
Boyette, P.E.
President
DeGolyer and
MacNaughton