The latest deal in a wave of US energy consolidation was announced on Monday. Shale oil producer Cimarex Energy and Cabot Oil & Gas revealed a “merger of equals” that will create a group with an enterprise value of $17bn. The combination brings together Cimarex’s oil assets in the prolific Permian shale field of West Texas and New Mexico, and Cabot’s acreage in northeast Pennsylvania’s Marcellus Shale, the biggest US gasfield.