On November 25, 2003, the Application for Permit to Drill (APD) the exploratory well was approved by the Minerals Management Service (MMS); this application was subsequently modified and approved by MMS on July 15, 2004. Nexen Petroleum U.S.A. Inc. contracted Transocean Inc. to conduct the drilling operations of the Green Canyon 242 (OCS-G 21788) Well No. 1. The semi-submersible Rig Marianas, owned and operated by Transocean Inc., was moved and moored onto the well location on August 30, 2004.