A drilling rig having a deck capable of being used offshore and a method for commissioning a well using the drilling rig and a method for decommissioning a well using the drilling rig, wherein the drilling rig comprises: a cantilever which is mounted so as to be moveable in a first direction and a second direction; a Multi Purpose Tower mounted on the cantilever; a supporting cart disposed between the cantilever and the deck which in turn is movably fixed on the deck of the drilling rig; at least two friction reducing devices attached to the supporting cart; and wherein the cantilever can slide relative to the drilling platform.