OKLAHOMA CITY--( BUSINESS WIRE )-- Devon Energy Corporation ( NYS: DVN ) today announced the closing of its previously announced $1.4 billion joint venture agreement with Sumitomo Corporation. The joint venture covers approximately 650,000 net acres in the Cline Shale and the Midland-Wolfcamp Shale. Sumitomo will invest $1.4 billion in exchange for 30 percent of Devon's interest in these projects.