Vance previously served as Chairman and Managing Director of the Addax Petroleum companies in Nigeria, during the years that Addax Petroleum Nigeria achieved peak production of over 110k bopd and annual expenditures in excess of US$1 billion. Prior to joining Addax, Vance was an independent producer in the USA as Manager of Source Rock Energy LLC and heserved as Vice President of a non-conventional gas producer in the United States. Prior to these undertakings, Vance had spent 20 years with Chevron Corporation, working primarily internationally, in various roles of increasing responsibility.