Little known oil rig accidents

There are minor oil rig disasters that don't cause any significant damage either to the personnel or natural environment. For example, Houston based Mariner Energy's oil rig in the Gulf of Mexico that exploded in 2010 did not produce any significant leakage of crude oil.
All 13 rig workers were evacuated by a supply ship, none of them being seriously injured. In 2011 a supply ship struck a column of a rig drilling oil near the coast of Newfoundland. A 4x5 meter hole that resulted the collision has been promptly sealed. None of 15 rig workers and 90 ship crew members suffered, and the platform was able to continue drilling operations, even if the hole turned out as big as 20% of the rig column's surface.