Off Shore Oil Drilling?

Has anyone ever done off shore oil drilling? I am thinking about applying for a job as a Measurments while Drilling Engineer. Has anyone ever done this job? Or worked on a rig? What is it like? How many week there and how many weeks off? Was the work dangerous, or just involve 12-16 hour days? Whats better off-shore drilling or on-shore? like in the oil field?