National Oilwell Varco 2012 Annual Report Download - page 28

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Index to Financial Statements
Rotary table The principal piece of equipment in the rotary table assembly; a turning device used to impart rotational power to the drill
stem while permitting vertical movement of the pipe for rotary drilling. The master bushing fits inside the opening of the
rotary table; it turns the kelly bushing, which permits vertical movement of the kelly while the stem is turning.
Rotating blowout
preventer (Rotating Head)
A sealing device used to close off the annular space around the kelly in drilling with pressure at the surface, usually installed
above the main blowout preventers. A rotating head makes it possible to drill ahead even when there is pressure in the
annulus that the weight of the drilling fluid is not overcoming; the head prevents the well from blowing out. It is used mainly
in the drilling of formations that have low permeability. The rate of penetration through such formations is usually rapid.
Safety clamps A clamp placed very tightly around a drill collar that is suspended in the rotary table by drill collar slips. Should the slips fail,
the clamp is too large to go through the opening in the rotary table and therefore prevents the drill collar string from falling
into the hole. Also called drill collar clamp.
Shaker See Shale Shaker
Shale shaker A piece of drilling rig equipment that uses a vibrating screen to remove cuttings from the circulating fluid in rotary drilling
operations. The size of the openings in the screen should be selected carefully to be the smallest size possible to allow 100 per
cent flow of the fluid. Also called a shaker.
Slim-hole completions
(Slim-hole Drilling) Drilling in which the size of the hole is smaller than the conventional hole diameter for a given depth. This decrease in hole
size enables the operator to run smaller casing, thereby lessening the cost of completion.
Slips Wedge-shaped pieces of metal with serrated inserts (dies) or other gripping elements, such as serrated buttons, that suspend
the drill pipe or drill collars in the master bushing of the rotary table when it is necessary to disconnect the drill stem from the
kelly or from the top-drive units drive shaft. Rotary slips fit around the drill pipe and wedge against the master bushing to
support the pipe. Drill collar slips fit around a drill collar and wedge against the master bushing to support the drill collar.
Power slips are pneumatically or hydraulically actuated devices that allow the crew to dispense with the manual handling of
slips when making a connection.
Solids See Cuttings
Spinning wrench Air-powered or hydraulically powered wrench used to spin drill pipe in making or breaking connections.
Spinning-in The rapid turning of the drill stem when one length of pipe is being joined to another. Spinning-out refers to separating the
pipe.
Stand The connected joints of pipe racked in the derrick or mast when making a trip. On a rig, the usual stand is about 90 feet
(about 27 meters) long (three lengths of drill pipe screwed together), or a treble.
String The entire length of casing, tubing, sucker rods, or drill pipe run into a hole.
Sucker rod A special steel pumping rod. Several rods screwed together make up the link between the pumping unit on the surface and the
pump at the bottom of the well.
Tensioner A system of devices installed on a floating offshore drilling rig to maintain a constant tension on the riser pipe, despite any
vertical motion made by the rig. The guidelines must also be tensioned, so a separate tensioner system is provided for them.
Thermal desorption The process of removing drilling mud from cuttings by applying heat directly to drill cuttings.
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