It isn't all oil jobs, there are scads of support jobs as well. Even the fast food jobs pay pretty well, but housing is expensive.
Consider hiring on at your local Wal-Mart and transfer to work in ND. I have heard that housing is provided and the pay in Williston is significantly better than in other areas.
My brother knows folks in the oil field. Yes there is a ripple-effect of pay increases all around. (The local kid that used to work at Arby’s is now pulling in triple on a water truck, etc.)
Also - he said they find it hard to find good people that will stay on. After the first paycheck or two, lots of the workers think they are rich and head off to party or pay off their trailer back home.
I know after my first paycheck as a kid (30+ years ago) on an oil-rig I felt the same way. (Although I didn’t quit) I bought a dozen roses and a gold necklace for my girlfriend of two years. (I told my mom and she got mad, and called it a waste. So I bought my mom a dozen roses too!) Looking back, I wish I had just stuck to the roses! (I wonder if she still has that necklace?)