The assembly of well-control equipment including preventers, spools, valves, and nipples connected to the top of the wellhead.

Abbreviation: blowout preventer equipment

Abbreviation: barrels of oil per day.

To plug open perforations by using ball sealers.

A short length of pipe (a nipple) installed on top of the blowout preventer.

The top end of the nipple is flared, or belled, to guide drill tools into the hole and usually has side connections for the fill line and mud return line.

To close off, such as with a blank flange or bull plug.

The replacement of cations associated with the clay surface by those of another species, e.g., the conversion of sodium clay to calcium clay.

A solid disc used to dead end a companion flange.

The walking beam of a pumping unit.

A tube placed around the retrieving neck of a retrievable bridge plug to “catch” debris.

An expandable, cylindrically shaped gripping mechanism that is fitted into an overshot to retrieve fish from the borehole.

See grapple.

The main parts of the valves in a plunger-type oil-well pump.

1.

Reduce pressure by letting oil or gas escape at a low rate.

2.

To equalize or relieve pressure from a vessel or system.

At the conclusion of high-pressure tests or treatments, the pressure within the treatment lines and associated systems must be bled off safely to enable subsequent phases of the operation to continue.

The bleedoff process must be conducted with a high degree of control to avoid the effect of sudden depressurization, which may create shock forces and fluid-disposal hazards.

also known as bleed down.

A tubing sub made of abrasion-resistant material.

It is used in a tubing string where high-velocity flow through perforations may cause external erosion.

A friction wrench used in repairing oil-well pumps