The term “oil or gas field” is generally associated with a hydrocarbon prospect that has been declared commercial. As such there have been four gas field discoveries since exploration began offshore Ireland in the early 1970s, namely the Kinsale, Ballycotton and Seven Heads (Kinsale area) producing gas fields off the coast of Cork and the Corrib gas field off the coast of Mayo. The Kinsale and Ballycotton fields are subject to a single Petroleum Lease. The Corrib field and the Seven Heads field are each, respectively, subject to a Petroleum Lease. There have been no oil field discoveries to date.