A choke, used to regulate flow of fluid from a well.

Different sizes of beans are used for different producing rates.

To flatten and spread the strands in a wire rope.

A flow-control device employing a ball with a rotating mechanism to open or close the tubing medium.

1.

A settled volume of barite particles from a barite slurry placed in the wellbore, usually to seal off a pressured zone.

2.

A plug made from barite weighting materials that is placed at the bottom of a wellbore.

Unlike a cement plug, the settled solids do not set solid, yet a barite plug can provide effective and low-cost pressure isolation.

A barite plug is relatively easy to remove and is often used as a temporary facility for pressure isolation or as a platform enabling the accurate placement of treatments above the plug.

A bell-shaped hole dug beneath a pipeline to provide room for use of tools.

A chemical combination of barium, sulfur, and oxygen which forms a tenacious scale that is very difficult to remove.

See barite.

The person who holds one length of pipe while another length is being screwed into or out of it.

The pressure resulting from restriction of full natural flow of oil or gas or fluid head that exerts an opposing pressure to flow.

A spherical object used to pump down the drill string or tubing to trip, release, or otherwise operate certain hydraulic-type tools.

A portable servicing or workover rig that is self-propelled, using the hoisting engines for motive power.

Because the driver’s cab is mounted on the end opposite the mast support, the unit must be backed up to the wellhead.

See carrier rig.

To hold one section of an object such as pipe while another section is being screwed into or out of it.

1.

A valve used to regulate back-pressure on equipment or systems through which a fluid flows.

2.

A valve used to regulate automatically a uniform pressure on the inlet side of the valve.

To unscrew drillstring components downhole.

The drillstring, including drillpipe and the bottomhole assembly, are coupled by various threadforms known as connections, or tool joints.

Often when a drillstring becomes stuck it is necessary to “back off” the string as deep as possible to recover as much of the string as possible.

To facilitate the fishing or recovery operation, the backoff is usually accomplished by applying reverse torque and detonating an explosive charge inside a selected threaded connection.

The force of the explosion enlarges the female (outer) thread enough that the threaded connection unscrews instantly.

Backing off can also occur unintentionally.

A cylindrical ring, usually vise-shaped, employed to back up (or assist) a sealing member against extrusion under temperature and pressure.

The area above a packer between casing id and tubing od