Can anyone get a job in the oilfield?

Well, what a great question and maybe it should read...'who would want to work in the oilfield'?

Qualifications required;
for offshore jobs, apart from qualifications listed with categories below the minimum requirement is Offshore survival certificate and Medical certificate. I will add more info on the above later.

Drilling jobs;
basically start with no qualifications required and you start as a roughneck and work your way up over a period of time...the time period can be reduced if you know someone in the buisness or sometimes even if you are smart.
(Note: some companies are recruiting educated personnel who start as assistant drillers on a fast-track program)

Technical Jobs;
Qualifications are necessary for these posts, although if you can bluff it with an Agency for a couple of months and are ok, then the drilling contractor could employ you through the agency.
I have heard of one guy who started as a Roustabout and was promoted to Electrician and whether he was an electrician or had qualifications I do not know.

Marine jobs;
Generally some sort of marine qualification is required.

Agency work;
Drilling contractors often use agencies to fill in for employees on the sick etc.
Agency hands get a day rate and do not generally get paid when they are off the rig. Drilling contractors employees are generally salaried and that means paid when they are on and off the rig.