For all designers: Most of my work is with drill ships. They have a ship shape. Images that may give you an idea of the vessels are on this page:
http://www.seadrill.com/drilling_units/drillships.The logo does not necessarily have to incorporate an image of a drill ship (we certainly like the shearwater bird concepts and other logo images as well), but if there is an offshore drilling rig in the logo it should be ship shape.
Thanks for all the concepts so far! Nice work.
Owen