Kosmos Energy Regulatory News (KOS)

KOSMOS ENERGY PROVIDES UPDATE ON EXPLORATION DRILLING PROGRAM OFFSHORE MAURITANIA

DALLAS, Texas, December 12, 2017 - Kosmos Energy (NYSE/LSE: KOS) announced today that it has completed drilling the Lamantin-1 exploration well located in Block C-12 offshore Mauritania in approximately 2,200 meters of water.

Lamantin-1 was drilled to a total depth of 5,150 meters and was designed to evaluate a previously untested Lower Campanian base of slope fan supplied from the Nouakchott River system, trapped in a combination structural-stratigraphic feature, and charged from underlying, oil-prone Cenomanian/Turonian and Albian source rocks. As interpreted from logs and samples collected during drilling and wireline operations, our evaluation suggests the Campanian reservoir objective was water bearing with some residual hydrocarbons. We believe the prospect failed due to a lack of trap, related to a combination of up-dip sand pinch-out and top/base seal effectiveness. The well will now be plugged and abandoned and the well results integrated into the ongoing evaluation of the significant remaining prospectivity in Kosmos' large acreage position.

Andrew G. Inglis, chairman and chief executive officer, said: "We are still in the early stages of exploring this newly emerging basin and our forward drilling program remains unchanged given the independent nature of the prospects. The drillship will now proceed as planned to test the independent Requin Tigre prospect offshore Senegal, which will be followed by two high-impact oil tests offshore Suriname in mid-2018."

The Requin Tigre prospect is a Cenomanian/Albian base of slope fan supplied from the proven Senegal River system, and is located approximately 150 kilometers offshore, 60 kilometers west of the Tortue discovery, and 80 kilometers north of the Yakaar discovery in approximately 3,100 meters of water. It is estimated that drilling will take approximately sixty days.

Kosmos holds rights in the C-6, C-8, C-12, C-13, and C-18 contract areas under production sharing contracts with the Government of Mauritania's Société Mauritanienne Des Hydrocarbures et de Patrimoine Minier (SMHPM). The blocks range in water depth between 100 and 3,000 meters, and have combined acreage of over 40,000 square kilometers gross. Kosmos is the exploration operator of Block C-12 with 28 percent equity and is joined by its partners BP (LSE: BP) (62 percent) and SMHPM (10 percent).

About Kosmos Energy

Kosmos is a leading independent oil and gas exploration and production company focused on frontier and emerging areas along the Atlantic Margin. Our assets include existing production and development projects offshore Ghana and Equatorial Guinea, large discoveries offshore Mauritania and Senegal, as well as exploration licenses with significant hydrocarbon potential offshore Suriname, Sao Tome and Principe, Equatorial Guinea, Morocco and Western Sahara. As an ethical and transparent company, Kosmos is committed to doing things the right way. The Company's Business Principles articulate our commitment to transparency, ethics, human rights, safety and the environment. Read more about this commitment in the Kosmos 2016 Corporate Responsibility Report. Kosmos is listed on the New York Stock Exchange and the London Stock Exchange under the ticker symbol KOS. For additional information, visit www.kosmosenergy.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements, other than statements of historical facts, included in this press release that address activities, events or developments that Kosmos expects, believes or anticipates will or may occur in the future are forward-looking statements. Kosmos' estimates and forward-looking statements are mainly based on its current expectations and estimates of future events and trends, which affect or may affect its businesses and operations. Although Kosmos believes that these estimates and forward-looking statements are based upon reasonable assumptions, they are subject to several risks and uncertainties and are made in light of information currently available to Kosmos. When used in this press release, the words "anticipate," "believe," "intend," "expect," "plan," "will" or other similar words are intended to identify forward-looking statements. Such statements are subject to a number of assumptions, risks and uncertainties, many of which are beyond the control of Kosmos, which may cause actual results to differ materially from those implied or expressed by the forward-looking statements. Further information on such assumptions, risks and uncertainties is available in Kosmos' Securities and Exchange Commission ("SEC") filings. Kosmos undertakes no obligation and does not intend to update or correct these forward-looking statements to reflect events or circumstances occurring after the date of this press release, except as required by applicable law. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement.

Inside Information

This announcement contains inside information. The person responsible for arranging the release of this announcement is Jamie Buckland, Vice President, Investor Relations.

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CONTACT:

Investor Relations

Jamie Buckland

+1-469-475-2687

jbuckland@kosmosenergy.com

Rhys Williams

+1-214-445-9693

rwilliams@kosmosenergy.com

Media Relations

Thomas Golembeski

+1-214-445-9674

tgolembeski@kosmosenergy.com