Casing without perforations

An integral part of a blowout preventer, which serves as the closing element on an open hole.

Its ends do not fit around the drill pipe but seal against each other and shut off the space below completely.

See ram

A fishing accessory run above a bit or a mill to recover small, nondrillable pieces of metal or junk.

1.

Barium sulfate; a mineral frequently used to increase the weight or density of drilling mud.

Its relative density is 4.2 (or 4.2 times denser than water).

See barium sulfate, mud.

2.

Weighting material with a specific gravity of 4.37 used to increase the apparent density of a liquid drilling fluid system.

Barite [baso4] is the most common weighting agent used today.

It is a mined material ground to an api specification such that particle sizes are predominantly in the 3 to 74 micron range.

Ph value above 7 and the ability to neutralize or accept protons from acids

An assembly of pulleys on a common framework; in mechanics, one or more pulleys, or sheaves, mounted to rotate on a common axis.

The crown block is an assembly of sheaves mounted on beams at the top of the derrick.

The drilling line is reeved over the sheaves of the crown block alternately which the sheaves of the traveling block, which is raised and lowered in the derrick by the drilling line.

When elevators are attached to a hook on the traveling block and drill pipe latched in the elevators, the pipe can be raised or lowered.

See crown block and traveling block.

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

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.