tour
A work shift of a drilling crew. Drilling operations usually occur around the clock because of the cost to rent a rig. As a result, there are usually two separate crews working twelve-hour tours to keep the operation going. Some companies prefer three eight-hour tours. The graveyard tour is the overnight shift or the shift that begins at midnight. (Pronounced "tower" in many areas.)
http://www.glossary.oilfield.slb.com/Display.cfm?Term=tour

Prime International "require" 3 tourpushers and one toolpusher for an onshore Drill Rig project. [czyli chyba jednego "ogólnego" i trzech zmianowych]
http://tinyurl.com/2yfpcv

http://tinyurl.com/2cw2rb
http://tinyurl.com/2xjjgu

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Note added at 9 mins (2008-11-07 22:19:32 GMT)
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Na wzór:
tool pusher - technik odwiertów głębokich
http://www.proz.com/kudoz/2053301