COMPANY ANNOUNCEMENT

For Immediate Release                                                                                               3 May 2013

Nexen Petroleum U.K. Limited (the "Company")

Change of Director

The Board wishes to announce that Kevin McLachlan resigned as a director of the Company on 26 March 2013.

For further information in relation to the above announcement please contact Lewis Harvey of Nexen Petroleum U.K. Limited, as follows:

Lewis Harvey

t: +44 (0) 1895 275822

e: harvey@nexeninc.com