Experience is invaluable. I agree with DubMac and would try to find a drilling contractor to work for. A lot of major oil and gas companies sub contract drilling out to drilling contractors, so that could be a way to get your foot in the door.
I would take a look at this and see if it helps you find what you are looking for.
http://www.yumpu.com/en/document/view/6548027/decommissioning-and-closure-plan-for-aughinish-srk-consulting
It is an interesting 16 page article that may help.
Good luck!
