Exxon Mobil Corporation Announces 2011 Reserves Replacement

Exxon
Mobil Corporation (NYSE:XOM) announced today that additions to its
proved reserves in 2011 totaled 1.8 billion oil-equivalent barrels,
replacing 107 percent of production. Excluding the impact of asset
sales, reserves additions replaced 116 percent of production.

'ExxonMobil replaced more than 100 percent of production for the 18th
consecutive year,? said Rex W. Tillerson, chairman and chief executive
officer. 'Our industry-leading position is a result of our strategic
focus on quality resource capture, a disciplined approach to investment,
and excellence in project execution. During challenging times for the
global economy, we continue to take a long-term view of resource
development and invest throughout the commodity price cycle. Adding
reserves enables ExxonMobil to develop new supplies of energy to meet
future demand and support economic growth and improved standards of
living.?

The annual reporting of proved reserves is the product of the
corporation′s long-standing, rigorous process that ensures consistency
and management accountability in all reserves bookings.

The corporation′s reserves additions in 2011 reflect new developments
with significant funding commitments as well as revisions and extensions
of existing fields resulting from drilling, studies and analysis of
reservoir performance. Reserve additions from the Kearl Expansion
Project in Canada totaled 1 billion oil-equivalent barrels. Proved
additions were also made in a diverse range of countries including the
United States, Nigeria, Norway, Indonesia and Malaysia. Asset sales in
2011 reduced proved reserves by 141 million oil-equivalent barrels.
Liquid additions totaled 1.4 billion oil-equivalent barrels for a 166
percent replacement ratio and gas additions totaled 0.4 billion
oil-equivalent barrels for a 49 percent replacement ratio.

At year-end 2011, ExxonMobil's proved reserves base increased to 24.9
billion oil-equivalent barrels. The proved reserves base is split 49
percent liquids and 51 percent gas.

Long-Term View

The long-term nature of the industry, and the large size of the discrete
projects that provide a significant portion of the corporation′s
reserves additions, make it appropriate to consider a time horizon
longer than a single year. The 10-year average reserves replacement
ratio is 121 percent, with liquids replacement at 99 percent and gas at
150 percent. The reserves additions made during this period comprise a
diverse range of resource types and have broad geographical
representation. ExxonMobil′s reserves life at current production rates
is 15 years.

Industry-Leading Resource Base

ExxonMobil added 4.1 billion oil-equivalent barrels to its resource base
in 2011, driven primarily by resource additions from the United States
and Canada, as well as Australia, Indonesia and Vietnam. These additions
include continued success in by-the-bit exploration discoveries,
undeveloped resource additions and strategic acquisitions. ExxonMobil′s
by-the-bit conventional exploration success in 2011 included discoveries
in the U.S. Gulf of Mexico, Australia, Indonesia and Vietnam. In
addition, discovery and delineation of North American unconventional
assets contributed significantly to the resource base. Overall, the
corporation′s resource base grew by 2.7 billion oil-equivalent barrels
to 87.2 billion oil-equivalent barrels, taking into account field
revisions, production and asset sales. The resource base includes proved
reserves, plus other discovered resources that are expected to be
ultimately recovered.

CAUTIONARY NOTE: Proved reserves in this release for 2009 and later
years are based on current SEC definitions, but for prior years the
referenced proved reserve volumes are determined on bases that differ
from SEC definitions in effect at the time. Specifically, for years
prior to 2009 included in our 10-year average replacement ratio,
reserves are determined using the SEC pricing basis but including oil
sands and our pro-rata share of equity company reserves for all periods.
Prior to 2009, oil sands and equity company reserves were not included
in proved oil and gas reserves as defined by the SEC. For years prior to
2009 included in our 18 straight years of at least 100 percent
replacement, reserves are determined using the price and cost
assumptions we use in managing the business, not the historic prices
used in SEC definitions. Reserves determined on ExxonMobil's pricing
basis also include oil sands and equity company reserves for all periods.

The reserves replacement ratio is calculated for a specified period
utilizing the applicable proved oil-equivalent reserves additions
divided by oil-equivalent production.

The terms 'resources? and 'resource base? include quantities of
discovered oil and gas that are not yet classified as proved reserves
but that are expected to be ultimately recovered in the future. The term
'resource base? is not intended to correspond to SEC definitions such as
'probable? or 'possible? reserves.

About ExxonMobil

ExxonMobil,
the largest publicly traded international oil and natural gas company,
uses technology and innovation to help meet the world′s growing energy
needs. ExxonMobil holds an industry-leading inventory of resources, is
the largest refiner and marketer of petroleum products, and its chemical
company is one of the largest in the world. For more information, visit www.exxonmobil.com.

ExxonMobil

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