Leadon and Gryphon are early Eocene age Fields located 23 km apart but which could not be more different in terms of their production performance from sand injectites. Both Fields are located in the Beryl Embayment of the UKCS North Sea. Sub seismic Frigg sand injectites are the developed reservoir in the Leadon Field. First oil was achieved in November 2001. The main Gryphon reservoir is basin floor high density turbidite sandstones within the Balder Formation which were developed from October 1993. Since August 2004 production started from wells drilled into seismic scale sand injection wings in the Balder.