National Oilwell Varco 2011 Annual Report Download - page 26

Index to Financial Statements
Drawworks The hoisting mechanism on a drilling rig. It is essentially a large winch that spools off or takes in the drilling line and thus
raises or lowers the drill stem and bit.
Drill Pipe Elevator (Elevator) On conventional rotary rigs and top-drive rigs, hinged steel devices with manual operating handles that crew members latch
onto a tool joint (or a sub). Since the elevators are directly connected to the traveling block, or to the integrated traveling
block in the top drive, when the driller raises or lowers the block or the top-drive unit, the drill pipe is also raised or
lowered.
Drilling jars A percussion tool operated manually or hydraulically to deliver a heavy downward blow to free a stuck drill stem.
Drilling mud A specially compounded liquid circulated through the wellbore during rotary drilling operations.
Drilling riser A conduit used in offshore drilling through which the drill bit and other tools are passed from the rig on the waters surface
to the sea floor.
Drill stem All members in the assembly used for rotary drilling from the swivel to the bit, including the Kelly, the drill pipe and tool
joints, the drill collars, the stabilizers, and various specialty items.
Formation A bed or deposit composed throughout of substantially the same kind of rock; often a lithologic unit. Each formation is
given a name, frequently as a result of the study of the formation outcrop at the surface and sometimes based on fossils
found in the formation.
FPSO A Floating Production, Storage and Offloading vessel used to receive hydrocarbons from subsea wells, and then produce
and store the hydrocarbons until they can be offloaded to a tanker or pipeline.
Hardbanding A special wear-resistant material often applied to tool joints to prevent abrasive wear to the area when the pipe is being
rotated downhole.
Hydraulic Fracturing The process of creating fractures in a formation by pumping fluids, at high pressures, into the reservoir, which allows or
enhances the flow of hydrocarbons.
Iron Roughneck A floor-mounted combination of a spinning wrench and a torque wrench. The Iron Roughneck moves into position
hydraulically and eliminates the manual handling involved with suspended individual tools.
Jack-up rig A mobile bottom-supported offshore drilling structure with columnar or open-truss legs that support the deck and hull.
When positioned over the drilling site, the bottoms of the legs penetrate the seafloor.
Jar A mechanical device placed near the top of the drill stem which allows the driller to strike a very heavy blow upward or
downward on stuck pipe.
Joint 1. In drilling, a single length (from 16 feet to 45 feet, or 5 meters to 14.5 meters, depending on its range length) of drill pipe,
drill collar, casing or tubing that has threaded connections at both ends. Several joints screwed together constitute a stand of
pipe. 2. In pipelining, a single length (usually 40 feet-12 meters) of pipe. 3. In sucker rod pumping, a single length of sucker
rod that has threaded connections at both ends.
Kelly The heavy steel tubular device, four-or six-sided, suspended from the swivel through the rotary table and connected to the
top joint of drill pipe to turn the drill stem as the rotary table returns. It has a bored passageway that permits fluid to be
circulated into the drill stem and up the annulus, or vice versa. Kellys manufactured to API specifications are available only
in four-or six-sided versions, are either 40 or 54 feet (12 to 16 meters) long, and have diameters as small as 2.5 inches (6
centimeters) and as large as 6 inches (15 centimeters).
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