Alot of oil companies have their own crews that do it, but if you can get in with them, than its good $. But you'll also be dragging your rig across those bumpy rock locations all the time. You'll also have to have a ton of water, unless they have a water truck on location to pull from, but even then, you will be changing filters out like its going out of style. The best advice I can give, is to wash the rigs on their yard's when they rig down and are between drilling jobs. Or have a PW rig dedicated to the oil patch life.