Consolidation in the U.S. exploration sector continued to gain steam Monday, with Contango Oil & Gas Co. announcing an all-stock merger with Mid-Con Energy Partners LP one day after a big tie-up in the Canadian oilpatch. 

Houston-based Contango works the shallow waters of the Gulf of Mexico (GOM) and across the Lower 48, mostly in Louisiana, Oklahoma, Texas and Wyoming. Mid-Con, formed in 2011 and which has Contango ties, focuses on enhanced oil recovery primarily in Oklahoma and Wyoming. 

For each common unit, Mid-Con unitholders would receive 1.75 shares of Contango common stock, representing a 5% premium based on a 15-day volume weighted average price. The exchange ratio implies an enterprise value for the combined entity of more than $400 million based on Friday’s closing...