Nexen Petroleum, the Houston-based unit of Canadaís Nexen Inc., has tapped Covington & Burling to work its proposed $15B acquisition by China National Offshore Oil Corp.

C&Bís team includes the legendary government relations pro Martin Gold. Along with the late Howard Liebengood, Gold built Gold & Liebengood into D.C.ís fifth largest lobbying firm before selling to Burson-Marsteller in 1989.

He also served as counsel to Senate Majority Leaders Howard Baker and Bill Frist and Sen. Mark Hatfield.

Gulf of Mexico assets represent about 10 percent of Nexenís overall assets. The Committee on Foreign Investment in the U.S. is examining the transaction.

CNOC has hired Hill+Knowlton Strategies and sister company Wexler Walker Public Policy Associates to work the deal.