The drill is what we punch the holes with. It has a rotary head that travels up and down the mast to turn the steel. On deep hole drills you will usually drill with mud or mud rotary, on shallower drills (like 3000 ft) you run air rotary or mud or you can drill reverse circulation, with an air driven hammer. Now a work over rig doesn't have a top or power head. Its really just a big winch for running casing tools or clean outs in and out of a hole that is all ready drilled. We use them for setting well casing allot of times or just reworking and older hole.What is the difference between a workover rig and a drilling rig in the oil field?
Well it mainly has to do with the quantum fluctuations in the differentiable manifold which is located by the sthochastic isentropic attractor.