Your biggest hurdle if you don't already do work for the oil companies will be getting all the required safety training, and each company will have their own program, and most require yearly refreshers.
One of our foreman that does a lot of work on gas wells in western PA and Ohio said it's the 'wild west', and seems to be a grey area where it's unclear who has jurisdiction as far as electrical inspections goes.  I'm guessing the insurance company would be the most likely to inspect electrical installations on well pads, but those are usually periodic, and not something you would call for like a traditional inspection.
If you're unsure, ask your customer, as they most likely have an entire department dedicated to permits and compliance.