Deepwater drilling is definitely the big possibility. The Deepwater Horizon hurt American deepwater drilling a lot in the short term. Eventually oil price will go up to the point that deepwater drilling is both necessary and prevalent. That's the one good market for the 609 in my opinion.
The AW609 is being certified for 9 passengers & 2 pilots, probably because of FAA part 121. With such a small passenger load, the AW609 itself is probably not the best choice for offshore oil uses. However, I read recently that AW is working on another commercial tiltrotor, but we likely won't see much about it until after the AW609 enters service around 2016.