Oil Crisis
http://www.hanzismatter.com/2005/04/oil-crisis.html
油断大敵 is a Japanese phrase that means "unpreparedness is one's greatest enemy" or "he that is too secure is not safe".
But in Chinese, the tattoo above would then read as "lack/sever of oil, big enemy/problem" or "oil crisis".
オイルクライシスってかっこいいな。