A device fitted with shaped charges or bullets that is lowered to the desired depth in a well and fired to create penetrating holes in casing, cement, and formation.

1.

A scale of pressure differences in which there is a uniform variation of pressure from point to point.

For example, the pressure gradient of a column of water is about 0.433 pounds per square inch per foot (9.794 kilopascals per meter) of vertical elevation.

The normal pressure gradient in a formation is equivalent to the pressure exerted at any given depth by a column of 10 percent salt water extending from that depth to the surface 0.465 pounds per square inch per foot or 10.518 kilopascals per meter).

2.

The change (along a horizontal distance) in atmospheric pressure.

Isobars drawn on weather maps display the pressure gradient.

To place cement plugs into a dry hole and abandon it.

Abbreviation: pounds per square inch

Proved undeveloped reserves are those proved reserves that are expected to be recovered from future wells and facilities, including future improved recovery projects which are anticipated with a high degree of certainty in reservoirs which have previously shown favorable response to improved recovery projects.

A preventer having a unit of packing material whose closure depends on well pressure coming from below.

It is used primarily to strip pipe through the hole or allow pipe to be moved with pressure on the annulus.

A mobile submersible drilling structure consisting of a barge hull that rests on bottom, steel posts that rise from the top of the barge hull, and a deck that is built on top of the posts, well above the waterline.

It is used to drill wells in water no deeper than about 30-35 feet (9-10.7m).

Most posted barge submersibles work in inland gulfs and bays.

See submersible drilling rig.

Abbr.

Proved developed non producing (reserves).

see also proved developed reserves.

See plastic fluid

To force a device called a pig through a pipeline or a flow line for the purpose of cleaning the interior walls of the pipe, separating different products, or displacing fluids.

A mixing chamber, usually in a small tank or pod that uses a rotating paddle to mix the fluid and the additives.

A volume of fluid, without proppant, injected in front of a frac job to establish frac width.

Abbr.

Prove undeveloped (reserves).

see also proved undeveloped reserves.

Isolating a cement injection site between a packer and a plug prior to squeezing.

A completion with no packer.

Common where ever gas has to be kept away from esps and rod rumps.