Cased hole work?
Mainly, yes. Wireline, fracking, small legacy general work over and hot oil assets.
Had a proper drilling company but sold the rigs and crews during a boom to Patterson. Could have retired at 35, but was going crazy after a few months so took over my FILaw’s company in exchange for stock.
It’s now worth more than what I got out of drillco, lol.
Never borrow money, buy right, conserve cash, never over expand and you get wealthy simply by doing a good job.