keywords: encana nexen subsidiary buy canada
text: Nexen to Buy EnCana Unit for \$2.1 Billion  NEW YORK (Reuters) - Nexen Inc. has agreed to buy a  U.K.-based subsidiary of EnCana Corp. in an all-cash deal worth  \$2.1 billion, enabling Canada's fourth largest oil explorer to  expand into the U.K. sector of the North Sea.