Rig Glossary: R–S


Ram/Pipe Ram

The closing and sealing component on a blowout preventer. One of three types: blind, pipe, or shear, may be installed in several preventers mounted in a stack on top of the wellbore. Blind rams, when closed, form a seal on open hole that has no drill pipe in it; pipe rams, when closed, seal around the pipe; shear rams cut through drill pipe and then form a seal.


A hole in the rig floor, some 30 to 40 feet (9 to 12 metres) deep, which is lined with pipe that projects above the floor. Used to stow the kelly when not in use.

Reading Stamp

A flat small square area cut into body of the tooljoint pin end to which identifying information about the tubular is stamped on.


A tool used to enlarge the hole to the specified size, help stabilize the bit, straighten the wellbore if kinks or doglegs are encountered, and drill directionally. Helps to center the bit and keep the hole “in gauge” by creating an even diameter in the well bore.

Remote BOP Control Panel

A device placed on the rig floor that can be operated by the Driller to remotely actuate the cylinders that turn the control valves on the main BOP control unit.

Remote Choke Panel

A set of controls, usually placed on the rig floor, or elsewhere on location, that is manipulated to control the amount of drilling fluid being circulated through the choke manifold. This procedure is necessary when a kick is being circulated out of a well. See “Choke Manifold”.

Ride The Pipe

A term used to describe not pulling the slips out of the rotary table when the drill string is being raised through the rotary table.

Rig Up

The process of connecting all the components of the rig to prepare the drilling rig for making hole, for example, to place all the buildings and assemble all the rig components, tools and machinery before drilling is started.

Roller Chain

A type of chain that is used in some pipe spinners to transmit power by fitting over sprockets attached to shafts, causing rotation of one shaft by the rotation of another. Transmission roller chain consists of offset links, pin links, and roller links.

Roll Pin

A mechanical fastener that secures the position of two or more parts of a machine relative to each other. They have a body diameter which is larger than the hole diameter, and a chamfer on either one or both ends to help ease the pin into the hole. The spring action of the pin allows it to compress as it assumes the diameter of the hole. Also called a spring pin.

Rotary Table

The component of the rotary system used to impart rotational power to the drill string while permitting vertical movement of the pipe for rotary drilling. Modern rotary tables have a series of connected components; the rotary drive turns the rotary table, the rotary table turns the table bushing or master bushing, the master bushing turns the kelly bushing, the kelly bushing turns the kelly. The kelly bushings permits vertical movement of the kelly while the drill string is turning.

Rotating Head/Rotating Drilling Head

A rotating, low pressure sealing device used in drilling operations utilizing air, gas, or foam (or any other drilling fluid whose hydrostatic pressure is less than the formation pressure) to seal around the drill stem above the top of the BOP stack.


Safety Cable

A steel cable that has a clip on one end and a loop on the other. It is intended to be threaded through a piece of hanging equipment and around a support structure, such as a batten or truss, and then clipped to its loop.

Safety Hook

A hook that can be transformed into an eye by locking a hinged piece in place.

Safety Pin

A pin like device that fits into the end of the tong rear keeper pin to prevent it from dislodging and allowing the tong lines to become free when under strain.


The well cuttings obtained at designated intervals during drilling. From an examination of these cuttings, the geologist determines the type of rock and formations being drilled and estimates oil and gas content.

Saver Sub

An expendable substitute device made up in the drill string to absorb much of the wear between the frequently broken joints (such as between the kelly or top drive and the drill pipe).

Screw Thread Protector

Cast iron or rubber cup shaped devices that screw onto/into the box.


The flat lip at the top of the tubular threads that connects to an opposing seal when connecting two joints, to provide a pressure seal in the tubular.

Self-Contained Breathing Apparatus (SCBA)

An atmosphere-supplying respirator for which the breathing air source is designed to be carried by the user.

Set Back Area

The area to the side of the rotary table where the stands of pipe or drill collars are placed vertically into the derrick or mast of a drilling rig.


Shortened form of shale shaker. See shale shaker.

Shaker Box

A receiving tank situated at the end of the mud return line. The flow of mud comes into the bottom of the device and travels to control mud flow over the shale shaker. Also called a “Possum Belly”.

Shaker Screens

Screens used on a shale shaker to separate the cuttings from the mud, to control solids, and mud density.


A fine-grained sedimentary rock composed mostly of consolidated clay or mud. Shale is the most frequently occurring sedimentary rock.

Shale Shaker

A vibrating screen unit that is used to separate cuttings from the circulating fluid coming out of the wellbore. The separated cuttings vibrate over the end of the shakers to a shale bin and the drilling mud fall back into the mud tanks.

Shear Line Cutter/Hydra Shear

A hydraulic cutting device used to cut wire rope (drilling line).

Shear Ram

The component in a blowout preventer stack that cuts, or shears, through some of the drill string components and forms a seal against well pressure.


(Pronounced “shiv”.) A grooved pulley. A support wheel over which wire, or cable rides.

Sheppard Stick

A long pole that is used to unlock the blocks and unlatch the hook in order to trip in or out of the hole.

Slip Cutting

Horizontal cuts to the drill pipe usually caused by the drill pipe turning while sitting in the slips, causing the slip dies to cut into the drill pipe metal surface.

Slip Dies

Sets of toothed wedges that fit into the slips to grip tubulars and suspend them in the rotary table.


Wedge-shaped parts of the slips that sit in the rotary table to suspend the drill string in the rotary table.


A volume of mud that is more dense than the mud in the drill pipe and wellbore. It is used to displace the mud out of the drill pipe in order to pull a dry string.


A short piece of pipe that is placed on the end of a tool to add extra leverage when an item is being tightened or loosened.

Snub Lines

Steel cables attached to the end of the tongs to limit the travel motion range of the tongs when they are pushed back into a biting position or pulled forward.

Spinning Chain

A process no longer used by most drilling contractors. A relatively short length of chain attached to the tong pull chain on the manual tongs used to make up drill pipe. The spinning chain is attached to the pull chain so that a crewmember can wrap the spinning chain several times around the tool joint box of a joint of drill pipe suspended in the rotary table. After crew members stab the pin of another tool joint into the box end, one of them then grasps the end of the spinning chain and with a rapid upward motion of the wrist “throws the spinning chain”—that is, causes it to unwrap from the box and coil upward onto the body of the joint stabbed into the box. The driller then actuates the makeup device to pull the chain off the pipe body, which causes the pipe to spin and thus the pin threads to spin into the box.

Spiral Retaining Ring/Snap Ring

Spiral retaining rings are axially installed into housings/bores (internal) or onto shafts (external), making 360° contact with the groove.

Split Master Bushing

A master bushing that is made in two pieces.

Stabbing Guide

Used during making up a string of pipe aligning pin to box threads and preventing face damage and connection failure.

Stabbing Valve

A valve that is stabbed into the drill string, sitting in the rotary table to close off the inside bore of the drill string and isolate the rig floor area from wellbore pressures.


A component of the Bottom Hole Assembly that helps keep the bit drilling straight as it works through different rock formations.


A stand of tubulars is two or three joints of drill pipe, drill collars, heavy-weight drill pipe connected together and stood in the derrick vertically, usually while tripping pipe. A stand of drill collars may be made up of drill collars and a drill collar pick-up sub.


A vertical pipe rising along the side of the derrick or mast, which joins the discharge line leading from the mud pump to the rotary hose and through which mud is pumped going into the hole.

Stopper Pins

Steel pins attached to the ends of the pipe racks that can be positioned to prevent tubulars from rolling off the ends of the pipe racks.

Stripping Rubber/Pipe Wipers

A rubber, donut shaped disk used to wipe mud and other fluids off tubulars as they are being pulled from the well bore.

Stuck Pipe

Drill pipe, drill collars, casing, or tubing that has inadvertently become immovable in the hole. Sticking may occur when drilling is in progress, when casing is being run in the hole, or when the drill pipe is being hoisted.


The top part of a tubular that is suspended in the slips above the rotary table.


A short, threaded piece of pipe used to adapt parts of the drilling string that cannot otherwise be screwed together because of differences in thread size or design. A sub (a substitute) may also perform a special function. Pick-up subs are used with drill collars to provide a shoulder to fit the drill pipe elevators; a kelly saver sub is placed between the drill pipe and the kelly to prevent excessive thread wear of the kelly and drill pipe threads; a bent sub is used when drilling a directional hole.

Sub Rack

A rack used for storage of different subs used in the drilling process.

Submersible Pump

A pump that is placed below the level of fluid in a well. It is usually driven by an electric motor and consists of a series of rotating blades that impart centrifugal motion to lift the fluid to the surface.


The substructure is an assembly of heavy beams used as the foundation on which the derrick or mast and usually the drawworks sit; provides the height and space to install blowout preventers, the casing head, and so forth.

Surface Casing

The first string of casing (after the conductor pipe) that is set in a well. It varies in length from a few hundred to several thousand feet (metres).

Survey Barrel

A weighted bar instrument that has a survey clock and survey instrument inside, that is lowered into the inside of the drill string to measure the deviation of the well bore.


A rotary tool that is hung from the rotary hook and traveling block to suspend and permit free rotation of the drill string. It also provides a connection for the kelly hose and a passageway for the flow of drilling fluid into the drill string.

Courtesy of Ensign Drilling Inc.