Oil & Gas Terms in Category P


To pierce the casing wall and cement to provide holes through which formation fluids may enter or to provide holes in the casing so that materials may be introduced into the annulus between the casing and the wall of the borehole.

Perforating is accomplished by lowering into the well a perforating gun, or perforator, that fires electrically detonated bullets or shaped charges.

Peptized clay

A clay to which an agent has been added to increase its initial yield

Packed-hole assembly

A bottomhole assembly consisting of stabilizers and large-diameter drill collars arranged in a particular configuration to maintain drift angle and direction of a hole.

Packer fluid

A liquid, usually salt water or oil, but sometimes mud, used in a well when a packer is between the tubing and the casing.

Packer fluid must be heavy enough to shut off the pressure of the formation being produced, must not stiffen or settle out of suspension over long periods of time, and must be noncorrosive.


(n) a device with an elastomer packing element that depends on pressure below the packing to effect a seal in the annulus.

Used primarily to run or pull pipe under low or moderate pressures.

This device is not dependable for service under high differential pressures.

Also called a stripper.


A substance occurring naturally in the earth and composed mainly of mixtures of chemical compounds of carbon and hydrogen, with or without other nonmetallic elements such as sulfur, oxygen, and nitrogen.

The compounds that compose it may be in the gaseous, liquid, or solid state, depending on their nature and on the existent conditions of temperature and pressure.

Pad volume

The amount of fluid placed in a well to serve as a pad, which is a special fluid used for any special purpose.


A piece of downhole equipment, consisting of a sealing device, a holding or setting device, and an inside passage for fluids, used to block the flow of fluids through the annular space between the tubing and the wall of the wellbore by sealing off the space between them.

It is usually made up in the tubing string some distance above the producing zone.

A packing element expands to prevent fluid flow except through the inside bore of the packer and into the tubing.

Packers are classified according to configuration, use, and method of setting and whether or not they are retrievable (that is, whether they can be removed when necessary, or whether they must be milled or drilled out and thus destroyed).


A liquid hydrocarbon of the paraffin series


An increased dispersion of solids in a liquid caused by the addition of electrolytes or other chemical substances.

See deflocculation, dispersion.

Packing gland

The metal part that compresses and holds packing in place in a stuffing box.

See stuffing box.


A hole made in the casing, cement, and formation through which formation fluids enter a wellbore.

Usually several perforations are made at a time.


See pay sand.

Perforated spacer tube

A ported, extended production tub used as an alternative path for wireline measuring devices.

Packer squeeze method

A squeeze cementing method in which a packer is set to form a seal between the working string (the pipe down which cement is pumped) and the casing.

Another packer or a cement plug is set below the point to be squeeze-cemented.

By setting packers, the squeeze point is isolated from the rest of the well.

See packer, squeeze cementing.