W liczbie pojedynczej pracownik pomocniczy. Zarówno przy tej nazwie zawodu, jak i przy innych, podałbym oryginalny termin w nawiasie (można też rozważyć posługiwanie się wyłącznie terminem angielskim - każdy z tych pracowników ma wiele obowiązków i trudno to oddać w tłumaczeniu). Niewykluczone, że w żargonie "nafciarzy" używane są tylko angielskie wersje.

Roustabouts and roughnecks work as part of a small team on offshore oil or gas drilling rigs or production platforms. Roustabouts do unskilled manual laboring jobs on rigs and platforms and roughneck is a promotion from roustabout.

The primary job of a Roustabout is to help with the drilling activities aboard the oil rig.

Additional responsibilities include:

• maintenance of the drilling area
• cleaning, scraping and painting the deck, equipment and work areas
• offloading supplies from boats and moving them to storage areas
• guiding the crane as loads are moved about the deck
• supplying equipment to the rig floor as requested
• mixing and conditioning drilling mud

Roughnecks do practical tasks directly involved in the drilling operation, under the supervision of the driller or assistant driller.

The Roustabout will also assist Roughnecks on the drill floor when required. This usually only happens when the Roughnecks are too busy to get a meal break. The Roustabout will get his meal, then go to the drill floor allowing one Roughneck to get his break. Then each Roughneck swaps out until everyone has eaten. Roustabouts are often members of the stretcher party.
http://www.oilfielddirectory.com/article/detail.php?id=140