Becoming an offshore welder is primarily a matter of experience and preparation; the opportunity is always there for those who are both prepared and diligent. If becoming a welder offshore is an ambition of yours, then there is a pretty set standard for what is needed to apply. Beyond that, however, if you go the extra mile and do what most others won't, your odds of getting hired go up by an order of magnitude.
It is important to already have become a certified welder before applying to work offshore, and to preferably have a good deal of experience under your belt as well. The reason for this is that the offshore environment is challenging enough on it's own without having to pick up a new trade or skill 40 miles out at sea. Being certified shows a certain accomplishment and determination, which the contractors that service the rigs with welding services like to see.
If you haven't yet become a certified welder, or are still in school, then stay in school and finish your technical education before even thinking about applying offshore. While a high school degree is a definite plus, the really important thing is to have graduated from a certified vocational or technical school, or undergone a welding apprenticeship.
Once you have your welder's certificate, consider applying offshore as a roustabout first. You'll no doubt be put to work as a welder's assistant, but this will allow you to learn the protocols and procedures unique to working offshore. Additionally, you'll get to work with a highly experienced welder or welders who can show you the ropes of working on an offshore rig, as well as train you in the use of specialized equipment that may be used on the rigs.
A big plus when going to apply for offshore welding jobs is to already have your ducks lined up in a row in terms of obtaining required training and certification that offshore workers need to have. Now, in many if not most cases, contractors will pay to have potential employees put through these courses before shipping them off to the rig. However, if you do this yourself ahead of time, not only will you show initiative and preparation, you'll impress your potential boss as well.
The certificates required are HUET, short for Helicopter Underwater Escape Training; First Aid, and Offshore Survival Training. Believe me, these are courses you really want to take; make no mistake, working offshore is dangerous. A recent helicopter crash transporting 19 workers from Scotland to the rigs in the North Sea shows the value of the training - all 19 survived, and all had the training required to do so.
Now many employers may not require you to take these courses, but doing so will not only impress them, it will provide you with peace of mind yourself, and give you the knowledge and confidence that you can handle almost any situation that may arise when working offshore.
Ultimately, working as on offshore welder is a matter of getting the right training, applying with the right contractors, getting hired, and staying safe. The pay is great, as is the experience, and you'll have a lot of downtime between hitches to enjoy the oil worker lifestyle. What are you waiting for?