Since the Kinsale, Seven Heads and Ballycotton gas fields ceased production in July 2020, the Corrib gas field has been the only producing field offshore Ireland. Prior to the commencement of production, the Corrib gas field was originally estimated to hold in the order of one trillion cubic feet of gas. Production commenced in December 2015, reaching a production plateau at the beginning of 2018. Since that point, production at Corrib has been in decline and is currently projected to cease in approximately 2030. While petroleum authorisation holders may generate their own resource estimates for their prospect, these are unproven volumes and are only an estimate of what might be present, based on the available geological and geophysical data.