Oil & Gas Terms in Category P

Parted rods

Sucker rods that have been broken and separated in a pumping well because of corrosion, improper loading, damaged rods, and so forth.

Perforation depth control log (pdc log)

A special type of nuclear log that measures the depth of each casing collar.

Knowing the depth of the collars makes it easy to determine the exact depth of the formation to be perforated by correlating casing-collar depth with formation depth.


An opening or space within a rock or mass of rocks, usually small and often filled with some fluid (water, oil, gas, or all three).

Compare vug.

Pressure loss


A reduction in the amount of force a fluid exerts against a surface, such as the walls of a pipe.

It usually occurs because the fluid is moving against the surface and is caused by the friction between the fluid and the surface.


The amount of pressure indicated by a drill pipe pressure gauge when drilling fluid is being circulated by the mud pump.

Pressure losses occur as the fluid is circulated.


A big tool for a small job, used to overcome some excess friction.

Pit volume totalizer (pvt)

Trade name for a type of pit-level indicator.

See pit-level indicator.

Portable mast

A mast mounted on a truck and capable of being erected as a single unit.

See telescoping derrick.

Pound equivalent

A laboratory unit used in pilot testing.

One gram or pound equivalent, when added to 350 ml of fluid, is equivalent to 1 lb/bbl.

Pounds per gallon (ppg)

Ppg; a measure of the density of a fluid (such as a drilling mud).


Perforations in casing for the inflow of hydrocarbons and gas

Perforating gun

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.

Pressure gradient


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).


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

Isobars drawn on weather maps display the pressure gradient.

Plug and abandon (p&a)

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


Abbreviation: pounds per square inch

Proved undeveloped reserves

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.