Discover the IHRDC Energy Glossary_beta

P Chart

An attribute control chart that is used to plot the percentage of defective products produced by a process

P&ID

Piping and Instrumentation Diagram. A blueprint drawing that shows all the piping, instrumentation, and their respective specifications.

P-N junction

The area or point where an N-type material and a P-type material physically contact each other in a semiconductor.

P-N-P Transistor

A bi-polar transistor that contains two P-type elements (poles) and one N-type element.

P-type material

A semiconductor material that has a lack of electrons.

PC

Personal computer, usually used to collect and arrange data into a manageable form.

PCC

Point of Common Coupling. An electrical junction where measurements of harmonic distortion are commonly made.

PD Meter

A positive displacement meter which measures volume of liquid.

PIC Box

An interface adapter that mounts external to a standard PC and allows the PC to communicate on Allen-Bradley's Data Highway networks

PID Control

A control algorithm that includes proportional, integral, and derivative factors

PK Pneumatic Tester

An instrument using dead weight to test the accuracy of the differential.

PLC

Programmable Logic Controller. A common type of controller well-suited for discrete logic decisions, used to operate sections of automated systems typically involving dozens of inputs and outputs, including variable speed drives.

PPR

Pulses Per Revolution. An encoder specification indicating how many pulses the encoder produces for each revolution of the motor shaft.

PROFIBUS

An open network protocol for connecting groups of input and/or output devices to a PLC system

PROFIBUS Protocol

A standard communications protocol that governs the transmission of data through networks

PSF

Pounds per square foot, a measurement of pressure.

PSI

Pounds per square inch, a measurement of pressure.

PSV

Pressure Safety Valve

PVC

Polyvinyl chloride, a rigid plastic widely used for pipe and fittings in water and gas service, drains and vents, sewer piping and irrigation systems, and other applications.

PVT Analysis

Pressure-Volume-Temperature laboratory analysis in which researchers use various instruments and techniques to determine reservoir fluid behavior and properties from oil and gas samples.

PWM

Pulse Width Modulation (or Modulated): a common type of inverter drive

PWM Pulse

Pulse Width Modulation pulse. A single pulse of voltage that is part of a sequence of applied voltages used to drive a motor in a variable speed application.

Packed-bed tower

A scrubber that uses a scrubbing liquid and packing to remove contaminants from a gas or vapor stream.

Packer

A packer is a device that can be run into a wellbore that then expands to seal the wellbore.

Packing

In pumps and valves, a flexible, leak-resistant material (often tough, rope-like, impregnated with lubricant) that surrounds a valve stem or pump shaft to control leakage. In distillation, ceramic, carbon, or metallic saddles, rings, or other shaped pieces in a still column for intermingling liquid and vapor.

Packing group

One of three categories established by the Department of Transportation to specify the packaging requirements for hazardous materials.

Packing of Grains

The distribution of grains and intergranular spaces (either empty or filled with cement or fine-grained matrix) in a sedimentary rock. Controlled by grain size, shape, and degree of compaction; determines the rock's bulk density.

Paddle-type dryer

A type of rotary dryer that uses heat and rotating paddles to dry materials.

Paleontology

The scientific study of the history of life in the geologic past, involving the examination of both animal and plant fossils to identify geological strata, classify organisms, date layers of the Earth, and reconstruct past environments and climates.

Pallet

A portable platform for handling, storing, and moving materials and packages.

Pallet Jack

A forklift that is powered manually or by an electric motor, used when material must be moved from one location to another but not stacked.

Palynology

The scientific study of pollen, spores, and other acid-insoluble organic plant fossils and microscopic fragments of larger organisms, used in stratigraphy, historical geology, and paleontology.

Parabolic Dunes

Parabolic dunes are U-shaped sand ridges with their concave side toward the wind.

Paraffin

A hydrocarbon whose carbon atoms are connected in a straight chain by single bonds. Heavier paraffins form a waxy substance found in some crude oils that often collects on tubing walls and restricts flow.

Paraffinic Oil

A paraffinic oil is an oil based on n-alkanes.

Paraffinic crude oil

Crude oil that contains a high proportion of paraffin.

Parallax

An optical illusion that can occur when an instrument with a pointer and scale is read from a position other than directly in front

Parallax (Error)

The erroneous perception of the position of an object caused by the direction or position from which it is viewed

Parallel Circuit

A circuit that has two or more parallel paths through which current can flow.

Parallel Connection

A type of connection between racks or devices where data is transmitted many bits (often a word) at a time. The physical medium is usually a multi-conductor cable.

Parallel Flow

A fluid flow pattern in a heat exchanger such that two fluids flow past each other in the same direction.

Parallel blade damper

A type of damper with parallel blades.

Parallel offset

The rerouting of pipe or tubing installed side by side or one over the other so that the configuration is neat and functional.

Parallel-tap Connector

A mechanical connector that is used for tapping a branch line off of a main conductor

Parallelogram

A four-sided, two-dimensional figure with two sets of parallel and equal sides; a rectangle, for example.

Paramagnetic Oxygen Analyzer

An analyzer that measures the oxygen concentration of a gas mixture based on the principle that oxygen is attracted to a magnetic field

Part

A subdivision of an article in the NEC

Partial Completion

Partial completion occurs when the well only partially penetrates the formation.

Partial Condenser

A condenser that condenses most, but not all, of the vapors from a distillation tower

Participating or Working Interest

This term represents the oil and gas quantities or revenue available to the investors after all royalties have been paid. If the royalty is 15%, the Working Interest is 85% of production. The Working Interest owners are responsible for paying all costs. If there are multiple owners, they usually name one owner as the operator.

Particulates

Airborne contaminants in the form of small solid particles, dusts, mists, vapors, or gases, often left in exhaust gas after combustion or contained in gas or vapor streams.

Pathogen

Any disease-producing agent, especially a virus, bacterium or other microorganism.

Pay

The component of a reservoir that contains economically producible hydrocarbons; the gross reservoir quality thickness above the hydrocarbon contact.

Payment for Damages

Compensation paid to an owner of a property by the oil and gas company to cover losses or damages resulting from oil or gas operations.

Peak Value

The amount of voltage or current at the maximum positive or negative point on a sine wave

Peak Voltage

The maximum positive or negative voltage in an AC cycle

Peak Voltage (Vp)

The maximum voltage level measured from a zero reference point

Peak demand

The highest gas demand in any day in a year

Peak-to-Peak Value

The maximum change occurring during one cycle of alternating voltage or current, represented by the distance between the positive peak and the negative peak on a sine wave.

Peak-to-peak Voltage (Vp-p)

Voltage measured from the maximum point of a signal to its minimum point, usually twice the peak voltage

Pendant

A box that is suspended from an electrical cable and houses a crane's operating controls to enable an operator to control the crane from the floor or ground

Pendant lines

Fixed-Length wire ropes that extend from the top of a boom to a mast to support the boom

Penetration

A standard spec for most asphalts; a measure of hardness.

Pent

A prefix for the name of a hydrocarbon that has five carbon atoms.

Pentane

An organic compound with the formula C5H12—an alkane with five carbon atoms. A hydrocarbon of the paraffin series that is a liquid at atmospheric conditions, usually separated during fractionation and sent to the refinery.

Percent

A value expressed in terms of the number of parts per one hundred

Percent Solids Test

A test that indicates the amount of solids present in a solution

Percussion Sidewall Core

A core taken from the side of the borehole (perpendicular to it) by firing hollow, retrievable cylindrical bullets into the formation. The bullets remain connected to the sidewall coring gun by wires, and movement of the gun pulls the bullets from the borehole wall.

Performance Objective

A brief description of the intended outcome or result of training or a job; may also describe performance standards and equipment needed.

Performance Observation

See, Observation

Perimeter

The distance around a closed two-dimensional shape

Period

The time required for one complete cycle. The period equals 1/frequency.

Permanent Magnet

A piece of magnetic material made from ferromagnetic materials (such as iron, nickel, cobalt, rare-earth alloys, or lodestone) that retains its magnetism after being removed from a magnetic field.

Permeability

A very important property of reservoir rocks that is a measure of their ability to transmit fluids (gas, oil, or water) through them. High permeability means fluid passes through the rock easily. Typically measured in darcies or millidarcies.

Permeability Estimation with Nuclear Magnetic Resonance (NMR) Logs

Permeability estimation from NMR logs uses the fact of the pore-water relaxation time being inversely related to the surface area-volume (S/V) ratio of the pore space. The NMR estimate of permeability is based on theoretical and core-based models that show that permeability increases with increasing porosity and pore size.

Permeable

Having some permeability; the ability to transmit fluids like water or gas through interconnected pores and fractures.

Permeameter

Laboratory equipment used to measure a rock's permeability.

Permissible Exposure Limit (PEL)

The regulatory exposure limit set by OSHA on the amount or concentration of a substance in the air, adopted from the threshold limit values set by the ACGIH.

Permissible exposure limit

The maximum amount of a chemical to which most workers can be repeatedly exposed without adverse effect, as specified by OSHA. Generally based on the Threshold Limit Values published by the ACGIH and typically based on a time-weighted average concentration over a normal 8-hour workday.

Permit system

The employer's written procedure for preparing and issuing permits for entry and for returning the permit space to service following termination of entry.

Permit-required confined space (permit space)

A confined space that has one or more of the following characteristics:1. Contains or has a potential to contain a hazardous atmosphere;2. Contains a material that has the potential for engulfing an entrant;3. Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section; or4. Contains any other recognized serious safety or health hazard.

Permit-required confined space program (permit space program)

The employer's overall program for controlling, and, where appropriate, for protecting employees from, permit space hazards and for regulating employee entry into permit spaces.

Personal Statement [evidence]

As part of the knowledge evidence, the employee may provide a personal statement on a rare occasion when they cannot provide direct evidence. The assessor would confirm the content of the statement by questioning the employee. The account written by the employee describing how and why they did the task, which can:

• Prove knowledge and understanding
• Describe specific situations where no other evidence exists
• Explain other evidence where required

Personal protection equipment

Equipment or clothing designed to protect the user by preventing or reducing the effects of injuries.

Personal protective equipment

Specialized clothing or equipment worn by an employee for protection against a hazard. General work clothes (e.g., uniforms, pants, shirts or blouses), not intended to function as protection against a hazard, are not considered to be personal protective equipment.

Personal protective equipment (PPE)

Equipment that protects a worker from bodily injury.

Petrography

A branch of petrology that focuses on the detailed descriptions of rocks.

Petroleum

A material containing hydrocarbons that appears under the surface of some areas of the earth.

Petroleum Initially In Place

The total quantity of petroleum estimated to exist originally in naturally occurring reservoirs.

Petrology

The study of rocks, including their occurrence, origin, history, structure, texture, and composition.

Petrophysicist

A specialist who practices and has expertise in petrophysics.

Petrophysics

The study of the physical, electrical, and mechanical properties and rock/fluid interactions of petroleum systems.

Petrophysics, Petrophysical

Petrophysics is the study of the properties (physical, electrical, and mechanical) and the rock/fluid interactions of petroleum systems.

Phanerozoic time

Phanerozoic time refers to the current geological eon, spanning from around 541 million years ago to the present, characterized by an abundance of visible fossils due to the widespread presence of organisms with hard body parts like shells and bones. This signifies a period of diverse and complex life on Earth. The word "Phanerozoic" means "visible life."

Phase

The degree to which AC waveforms are in step or out of step with each other, measured in degrees from the beginning of a cycle. Also, a state in which matter exists: gas, liquid, or solid.

Phase Change

A change in a state of matter, such as from a solid to liquid or from a liquid to a vapour

Phase Current

The current that flows through the coils or resistors in a three-phase system

Phase Difference

Phase difference is the difference in phase angle between two sinusoids or phasors.

Phase Shift Oscillator

An RC oscillator that produces a sine wave output.

Phase Voltage

The voltage that is applied across the resistors or induced in the coils of a three-phase system

Phase current or voltage

The value of current or voltage produced inside an AC Generator.

Phoenix Libraries

Photoconductive light

A light-sensitive diode that is used to control circuits that have an externally applied potential by sensing changes in light intensity. Also called a photodiode.

Photoelectric Absorption

Photoelectric absorption is the interaction of a gamma photon with matter in which the incident photon is completely absorbed, giving up all its energy by displacing and accelerating an inner shell electron.

Photoelectric Effect

A gamma ray interaction in which the gamma ray is fully absorbed by a bound electron. If the transferred energy exceeds the binding energy, the electron is ejected and replaced, emitting a characteristic X-ray dependent on atomic number. It occurs with highest probability at low gamma ray energy and high atomic number. The photoelectric effect is the principle behind the PEF log, which identifies lithology.

Photoelectric Effect, Photoelectric Factor

The photoelectric factor is a gamma ray interaction in which the gamma ray is fully absorbed by a bound electron. If the energy transferred exceeds the binding energy to the atom, the electron will be ejected. Normally, the ejected electron will be replaced within the material and a characteristic X-ray will be emitted with an energy that is dependent on the atomic number of the material. The highest probability for this effect occurs at low gamma ray energy and in a material of high atomic number. The photoelectric effect (PEF, Pe) is the principle behind the photoelectric (PEF) log, which identifies lithology.

Photoelectric Log

The photoelectric effect is a gamma ray interaction in which the gamma ray is fully absorbed by a bound electron. If the energy transferred exceeds the binding energy to the atom, the electron will be ejected. Normally, the ejected electron will be replaced within the material and a characteristic X-ray will be emitted with an energy that is dependent on the atomic number of the material. The photoelectric effect is the principle behind the photoelectric log, which identifies lithology.

Photometer

An instrument that measures the absorption of electromagnetic radiation

Photovoltaic light

A light-sensitive diode that uses the energy in light to produce a voltage that is the sole voltage source for its circuit.

Physical Layer

The lowest level of network protocol that governs the physical specifications for the mechanical and electrical interface

Physical hazard

A chemical or material that has the potential to catch fire, explode, or undergo some other violent reaction, including combustible liquids, compressed gases, explosives, flammables, organic peroxides, oxidizers, pyrophorics, unstable (reactive) substances, and water-reactive substances.

Pi (π)

A Greek letter designating the ratio between a circle's circumference and its diameter; the constant approximately equal to 3.14159.

Pi Filter Primary Winding

The transformer winding that is connected to the incoming power.

Pick-Up Current

The amount of current needed to reposition a relay element.

Pickett Plot

A Pickett plot is a visual representation of the Archie equation. It is a graphical technique for estimating the water saturation. A set of porosities and their corresponding resistivities taken from well logs and 2×4 cycle log-log paper are required. A Pickett plot also allows the estimation of the input parameters to the Archie equation.

Pickup Current

The amount of current needed to close relay contacts

Pictorial drawing

A type of drawing that is made from an angle so that several sides of an object are visible in a single view

Pie Graph

A circular graph that is typically used to compare the various parts of a whole to each other and to the whole; also called a pie chart

Piezoelectric Crystal

A piezoelectric crystal is a crystal, such as quartz, that produces a potential difference across its opposite faces when under mechanical stress.

Piezoelectric Transducer

A device that converts the deformation of solid materials into electrical charges, which other instruments can then interpret.

Piezoelectricity, Piezoelectric

Piezoelectricity is the electric charge that accumulates in certain solid materials in response to applied mechanical stress. Piezoelectricity means electricity resulting from pressure.

Pig

A device that is propelled into a pipeline to clean out accumulated residues or foreign matter.

Pig launcher

A device that uses fluid pressure to propel a “pig” into a pipeline.

Pig trap

A device used to catch a “pig.”

Pigtail

A short, added piece of wire, commonly used to extend or connect wires in a box.

Pilot

A small spring-loaded relief valve attached to a piston relief valve to control the pressure on top of the piston.

Pilot Device

A device that can be activated by specific changes in a process and used in a motor controller to perform a variety of functions, such as sending an alarm

Pilot Exciter

A small self-excited DC generator used in some excitation systems as a separate source of DC power for a main exciter, supplying direct current to the electromagnet in the stator of a DC exciter.

Pilot Wire Relay

A relay that compares three-phase current at the ends of a short transmission line and operates if the currents are unequal

Pilot Wires

Conducting wires, similar to telephone lines, that connect pilot wire relays

Pilot tube

A device, consisting of an inner tube and an outer tube, that can be used to measure pressure in a fan system.

Pilot-Operated Valve

A type of safety relief valve that has a separate sensing component (the pilot) to control the operation of the main valve.

Pin fastener

A non-threaded fastener that is a piece of solid material used to join items together

Pinch Valve

A valve that is closed by squeezing, or pinching, a tube

Pinch-off voltage

In JFET's, a critical magnitude of gate potential that causes the depletion region to expand sufficiently to close off the channel entirely, causing current flow to cease.

Pinion

The smaller gear in a pair of gears

Pipeline capacity

The volume of gas which is needed to maintain a full pipeline

Piping System Diagram

A diagram representing the major components and pieces of equipment in a piping system; includes flow diagrams and piping and instrumentation diagrams (P and IDs).

Piston

In a pilot-operated relief valve, a short cylinder used to close the path between inlet and outlet. In a reciprocating compressor, the device that causes gas compression within the cylinder.

Piston Pump

A reciprocating pump that uses a piston to move fluid.

Pitch

In fasteners, the distance from one thread crest to the next, normally expressed as threads per inch. In fans, the inclination or angle of the blades. In refining, leftover material at the bottom of a vacuum distillation tower.

Pitman Arm

A steel rod that connects the crank arm to the equalizer on the beam.

Placard

A diamond-shaped sign that is typically attached to bulk hazardous materials packaging to identify the contents of the packaging and the risks associated with the material.

Plan view

Any of several types of top-view drawings of a budding, such as a site plan, a floor plan, and a foundation plan

Planarity

Planarity occurs when at least two points in space define a plane.

Planned Shutdown

A normal furnace shutdown that is scheduled for reasons such as maintenance and repairs

Plant System

A group of connected components that function together to carry out a specific task

Plastic Electrical Tape

A plastic or vinyl insulating tape that can withstand higher voltages than rubber tape and friction tape

Plasticity

Plasticity is the quality of being easily shaped, or moulded.

Plate Valve

A suction or discharge valve that uses a flat plate which lifts and seats by differential pressure to control gas flow. This valve is used for high pressure compression requirements.

Play

An area in which hydrocarbon accumulations or prospects with similar characteristics occur, such as the Lower Tertiary play in the deepwater Gulf of Mexico or the Marcellus play in the eastern United States.

Play, Petroleum Play

A petroleum play, or simply a play, is a group of oil fields or prospects in the same region that are controlled by the same set of geological circumstances.[1] The term is widely and heavily used in the entire realm of exploitation of hydrocarbon-based resources.

Playas

A playa is a flat, dry, and vegetation-free area in a desert basin that is at the lowest point.

Plenum

See Inlet box.

Plug Valve

A valve whose flow control component is a plug with an opening through it. The valve is opened and closed by rotating the plug inside the valve body, providing a straight-through flow pattern. Designed for throttling.

Plug fuse

A type of fuse that is held in position by a screw thread contact.

Plumb

A surface or an object that is determined to be perfectly vertical

Plumb Bob

A weight attached to the end of a reel of flexible metal measuring tape, lowered into a liquid container to make innage or outage measurements. A type of direct level measurement device.

Plunger

A closely fitted hollow tubular piston operating in the barrel for displacing well fluid.

Plunger Element

A relay element in which a magnetic field attracts a plunger into a coil to close contacts

Plunger Pump

A reciprocating pump that uses a plunger to move fluid.

Pneumatic Control System

A safety control system that signals a pilot to shut off fuel supply to the prime mover, shutting down the compressor package.

Pneumatic drill

A power drill that is operated by compressed air or gas

Point (Data Point)

Point (Data Point) Any item associated with a process control loop and related to other monitoring and control devices on the loop (for example, analog input, digital output, control points, etc.)

Point Counting

Point counting is a statistical technique. It involves looking at a large number of points on the slide, recording exactly what is seen at each point and then assembling a description from all the information recorded.

Point-and-Click

The navigation method used in graphical user interfaces: a mouse or trackball cursor is positioned on an icon or object, then a button is pressed (making a "click" sound) to select the object or initiate a program

Point-to-Point

A type of network topology in which all of the devices on the network are directly connected to each other

Poisoned Catalyst

A catalyst that can no longer function properly

Poisson's Ratio

The negative ratio of transverse to axial strain. When a material is compressed in one direction, it tends to expand in the other two directions perpendicular to the direction of compression.

Poisson's ratio

The negative ratio of transverse to axial strain. When a material is compressed in one direction, it tends to expand in the other two directions perpendicular to the direction of compression.

Polarity

A pair of electric charges of equal magnitude but opposite sign, separated by some (usually small) distance.

Polarity Switch

A control on an analog test instrument that is used to select either positive or negative DC readings

Polarization Horns

Polarization horns are the effect on a propagation resistivity of charge build-up at the boundary between two formation layers with different dielectric properties.

Polarization Time

The polarization time (TW) in NMR logging is the time between the cessation of measurement of one echo train and the beginning of measurement of the next echo train.

Polarization analysis

This is an analysis applied to S-waves (a transverse wave) that determines the geometrical orientation of the wave motion.

Polarization index

The ratio of a ten-minute megohmmeter reading taken across the windings of an AC generator to a one-minute megohmmeter reading; the index indicates the condition of a generator's insulation.

Polarized Light

Polarized light waves are light waves in which the vibrations occur in a single plane.

Pole

That portion of a device that is associated exclusively with one electrically separated conducting path of the main circuit or device.

Pole pieces

The parts of a salient-pole rotor around which windings are wrapped.

Poles

The two areas on a magnet where the magnetic force is greatest.

Polished Rod

The top rod in a sucker rod string, made of highly polished and tempered steel.

Polling

An electronic signal that causes the EFC to send specified data.

Pollutant

A substance that is able to change the environment in a way that causes harm to plants, animals, or people when it is present in large enough amounts

Pollution

A discharge of harmful material into the environment above the limits set by regulatory agencies such as the Environmental Protection Agency.

Polycrystalline Diamond Bit

A polycrystalline diamond bit (PDC bit) is a special type of diamond drilling bit that does not use roller cones but instead has polycrystalline diamond inserts.

Polymer

A long-chain molecule made from identical or similar smaller molecules.

Polymerization

A reaction in which many similar molecules (such as olefins) are added together to form longer chain polymer molecules.

Pooling, Pooled Plots

In pooled plots, adjacent dips within a very small solid angle (2° to 3°) are presented as a single dip answer.

Pop Valve

A safety valve that "pops" open when the system pressure reaches the valve set point.

Poppet Value

A suction or discharge valve that uses round poppets which lift and seat by differential pressure to control gas flow. This valve is used for low pressure compression requirements.

Pore Pressure

The pressure of fluids within the pores of a reservoir (also called formation pressure), usually hydrostatic pressure or the pressure exerted by a column of water from the formation's depth to sea level.

Pore Throat

Pore throat is the connection between the pores, often a fraction of the pore size.

Porosity

The measure of a rock's ability to hold a fluid. Porosity is normally expressed as a percentage of the total rock which is taken up by pore space.

Porosity (\( \phi \))

The volumetric void space within rocks, being that space not occupied by solid material. Porosity is thus a measure of the reservoir's storage capacity.

Porosity (phi), Pores, Pore Spaces

Porosity, denoted by the Greek letter phi, is the volumetric void space within rocks, being that space not occupied by solid material. Porosity is thus a measure of the reservoir's storage capacity.

Porosity (phi), Pores, Pore Spaces, Porous

The volumetric void space within rocks not occupied by solid material, denoted by the Greek letter phi. Porosity is a measure of a reservoir's storage capacity.

Porous

Containing a network of small openings, or pores, capable of trapping substances in liquids and gases.

Port

An opening through which fluid enters, leaves, or passes in a valve body or compressor.

Portable band saw

A portable, hand-held power saw with a blade that is a continuous loop, or band, of thin, flat metal. The band is run around a set of motor-driven pulleys that drive and support the band.

Positive Displacement Meter

A mechanical, fluid measuring device that measures by filling and emptying chambers of a specific volume.

Positive Displacement Pump

A type of pump that uses a piston, diaphragm, gears, lobes, or other device in a reciprocating or rotary motion to push (positively displace) controlled amounts of fluid through the pump.

Positive Power

Power that is going to a load from a power source

Positive Pulse Telemetry

Telemetry systems that create a momentary flow restriction in the drill pipe that produces a pressure pulse higher than the drilling mud volume pressure.

Positive Seating

The condition when a valve disc is firmly in place against its seat which prevents leakage.

Positive pressure check

A check for leakage from a respirator when a positive pressure is created inside the respirator by exhaling.

Positive pressure respirator

A type of air-supplied respirator in which the tank continuously supplies air to the face mask at a pressure that is above atmospheric pressure.

Positron

The positron, or anti-electron, is the anti-particle or the anti-matter counterpart of the electron.

Possible reserves

Additional reserves that are less certain to be recovered than probable reserves.

Postproduction

The fourth step in a production process, which includes handling, storage, packaging, and delivery to the customer.

Posture

The position of the body. Generally speaking, good posture maintains the three natural curves of the spinal column. Good posture provides optimal back support and minimizes the risk of back injury.

Potassium

A chemical element with symbol K and atomic number 19. Orthoclase (potassium feldspar) is a common rock-forming mineral.

Potential

Voltage.

Potential Difference

The difference in electrical potential between two points. In particular, the spontaneous potential recorded on well logs is the electrical potential between a surface electrode and one in the wellbore.

Potential Energy

Energy related to position or elevation

Potential transformer

A transformer that reduces higher line voltage to a proportional lower voltage and supplies the lower voltage to protective relays or to instruments that monitor or measure the line voltage.

Potentiometric feedback amplifier

A variable gain inverting amplifier that used a potentiometer in its feedback path.

Pounding

The action of the plunger on the downstroke hitting the liquid surface in a partially filled pump.

Pour Point

The temperature at which a fuel can start being poured.

Power

The rate at which work is done or energy is transferred. Electrical power is calculated by multiplying current times voltage, measured in watts. In mathematics, a number indicating how many times a base number is multiplied by itself.

Power Factor

The ratio of true (working) power to apparent power for an AC circuit, expressed as a percentage or decimal number.

Power Line Carrier Channel

A transfer trip communication channel in which transfer trip signals are sent over a transmission line

Power jigsaw

A portable, hand-held power saw that cuts with an up-and-down motion and is typically used to cut curves, circles, irregular shapes and patterns, and openings in boards or panels. Also called a saber saw.

Power supply rejection ratio

The absolute value of the ratio of the change in supply voltages to the change in input offset voltage. Typically both supply voltages are varied symmetrically. Unless otherwise noted, both supply voltages are varied symmetrically.

Power transformer

Generally, a transformer that supplies power to a circuit to do work. In transmission and distribution systems, typically a transformer that supplies large amounts of power, usually more than 500 KVA.

Power transistor

A transistor designed to carry high current.

Pre-Fractionator

A binary distillation tower that separates the lighter components of crude before the crude enters an atmospheric tower.

Precipitate

A solid substance that falls out of solution during a chemical reaction

Precipitation

A process by which a dissolved solid comes out of solution

Precipitator

A device used to separate particulates from exhaust gas leaving a boiler

Predictive Modeling

Predictive modeling is the process of using known results to create, process, and validate a model that can be used to forecast future outcomes.

Preset

A memory word in which a timer or a counter stores the maximum time or count

Pressure

The amount of force applied per unit of area, often expressed in pounds per square inch (psi).

Pressure Build Up Test

A pressure build up test is used for determining the effective drainage radius of a wellbore in addition to the presence of permeability barriers or other production deterrents; the well is shut for a specified period, and a bottom hole pressure bomb is run to record the reservoir pressure.

Pressure Cutout Switch

A switch that turns a reciprocating compressor on or off in response to changes in pressure.

Pressure Differential Indicator

An indicator that displays the difference in pressures measured at two different points

Pressure Differential Transmitter

A transmitter produces a signal that is proportional to the difference in pressure between the two points in a system

Pressure Drop

A loss of pressure that results when a fluid passes through a constriction or smaller area such as an orifice plate.

Pressure Gauge

A pressure device used to measure pressure. Many different types of pressure gauges have been developed for use in well testing over the years. These include helical bourdon tube gauges, strain gauges, quartz crystal gauges and surface readout gauges.

Pressure Override

The difference between the full flow pressure and the cracking pressure of a spring-biased valve

Pressure Packing

Rings within a cage that surround the piston rod to form a seal which prevents pressurized gas from escaping into the atmosphere or the crankcase.

Pressure Reducing Valve

A pressure control valve designed to lower the pressure in one part of a hydraulic or other system.

Pressure Relief Valve

A general term used for relief valves, safety valves, and safety relief valves.

Pressure Switch

A pilot device set to actuate at a specific set point based on process pressure, often installed to initiate alarms or start standby equipment if abnormal pressure conditions develop.

Pressure Taps

Threaded holes located on a meter tube or orifice fitting where upstream and downstream static pressures are taken.

Pressure Transient Analysis

Pressure transient analysis is the analysis of pressure changes over time.

Pressure Transient Well Tests

In pressure transient well tests, the pressure is recorded as a function of time and interpreted using various analysis methods. These include build-up tests and drawdown tests in production wells and falloff tests in injection wells. Pressure transient well test analysis procedures are based on classical mathematical relationships between flow rate, pressure and time.

Pressure Transmitter

A device that converts a pressure measurement to a signal and sends that signal to another device, such as a recorder that is located some distance away

Pressure Vent

A vent that is used to release excess pressure from a tank

Pressure cutout switches

Switches that turn a reciprocating compressor on and off in response to changes in pressure.

Pressure filter dryer

A type of dryer that uses pressure and a hot gas, usually nitrogen, to force moisture out of wet cake that is on a mesh screen inside the drying vessel.

Pressure tank

A tank designed to store liquids at pressures above 0.5 psig (higher than atmospheric pressure).

Pressure tank cars

Tank cars that have working pressures greater than 100 psi.

Pressure vents

Vents that are used to release any excess pressure that builds up in a tank.

Pressure-compensated Flow Control Valve

A flow control valve that has a structure built in to sense upstream pressure and adjust to it to maintain a constant pressure drop

Pressure/vacuum (P/V) valve

A valve designed to provide normal venting to a storage tank; also called a breather valve or a conservation vent.

Pressurized tank

See High pressure tank.

Pretreating

The process and activities associated with the removal of contaminates (especially sulfur).

Preventive Maintenance

Systematic monitoring and testing of equipment to detect conditions that could lead to failure, and performance of routine maintenance in order to delay failure

Primary Burn

See Catalyst burn.

Primary Coil

The coil in a transformer to which power is applied.

Primary Element

Part of a meter station, consisting of the meter tube, orifice fitting (or flange unions), and orifice plate (or metering device).

Primary Loop

The outer, or master, control loop in a cascade control system that provides the set point for the secondary, inner, or slave loop

Primary Winding

The coil or winding in a transformer that receives the incoming power (to which voltage is applied).

Primary vessel

A vessel that is a major, or central, part of a process system.

Prime mover

A piece of equipment (such as a turbine, motor, or engine) that provides the mechanical energy necessary for operating an AC generator, beam pumping unit, or other equipment.

Primer

A solvent that breaks down the surface of plastic pipe and fittings so that cement will more completely join the two, making a good seal for pipe joints.

Prior learning

See, Accreditation of Prior Achievement (APA)

Pro

A prefix for the name of a hydrocarbon that has three carbon atoms.

Probabilistic

Probabilistic is being based on, or adapted to, a theory of probability; subject to, or involving, chance variation.

Probable reserves

Additional reserves that are less certain to be recovered than proved reserves but which, together with proved reserves, are as likely as not to be recovered.

Probe

A device inserted into a meter tube for taking samples, which may be elbow-shaped, beveled, or a straight tube made of stainless steel. Also, a short, pointed metal tool for testing the hardness of drill cuttings.

Process Delay

The time between when a control action takes place and when the process has substantially destabilized in response to that action; includes lag and dead time

Process Disturbance

Any unwanted change in a system that tends to adversely affect the value of a controlled variable

Process Gain

The proportionality between the control output and the process variable through the process (rather than through the controller); the relationship between a change in controller output and the resulting change in a process variable.

Process Gas

Gas present during or produced by a process or piece of equipment.

Process Instrumentation

Instruments that monitor and/or control process variables

Process Load

The demand for the output of, and the input to, a process. Any change in load reflects back on control loops as a process upset.

Process Variable

A physical condition of process materials (such as temperature, level, flow rate, pressure, pH, or turbidity) that changes and is measured, manipulated, or controlled by a control loop.

Process control system

A group of instruments used to automatically control the values of process variables.

Process of Elimination

A troubleshooting method in which circuit components or parts of a process that are working properly are eliminated from consideration until only the source of the problem remains.

Process reaction

A chemical change in which the atoms or ions of one or more substances are rearranged to form one or more new substances.

Processing

The second step in a production process, in which the necessary physical or chemical changes are made to feedstocks in order to produce the final product.

Produced water

Water produced in connection with, or generated during, oil and natural gas exploration, development, and recovery operations.

Product

The answer to, or result of, a multiplication problem

Product Quality Report

A document that notifies the customer that the finished product meets the agreed-upon specifications; also called a product brief or a certificate of analysis.

Production Log

Production logs are run in completed wells to determine the nature and behavior of fluids in, and around, the borehole during production or water injection.

Production Log, Production Logging

A production log is a record of one or more in-situ measurements that describe the nature and behavior of fluids in or around the borehole during production or injection. Production logs are run for the purpose of analyzing dynamic well performance and the productivity or injectivity of different zones, diagnosing problem wells, or monitoring the results of a stimulation or completion.

Production Phase

The phase of petroleum operations in which oil and gas is produced, processed and sold to the regional market.

Production Profile

A production profile is the quantity of hydrocarbon produced over successive periods of time.

Production Tubing

The tubing string used to transport the well fluids to the surface.

Production Tubing, Tubing

Production tubing is a wellbore tubular used to produce reservoir fluids. Production tubing is assembled with other completion components to make up the production string.

Production sharing contract (PSC)

An agreement between a host government and the owners (or co-owners) of a well or field regarding the percentage of production each party will receive after the parties have recovered a specified amount of capital and operational expenses.

Productive well

A well that is capable of producing hydrocarbons in sufficient quantities to justify commercial exploitation.

Productivity Index

A mathematical measure of a well's potential or ability to produce, expressing the ability of a reservoir to deliver fluids to the wellbore. Usually stated as volume delivered per psi of drawdown at the sandface (bbl/d/psi). The symbol J is commonly used, preferred by the Society of Petroleum Engineers.

Proficiency statements

Profit Oil

The share of production remaining after the Cost Oil and, if applicable, Royalty and First Tranche oil, have been paid. The Profit Oil is shared between the Government and the Operator on a fixed (65:35 %) or sliding scale.

Progradation

The seaward growth of a beach, delta, or fan by the progressive deposition of sediments by rivers or shoreline processes.

Program Files

One of two main types of PLC files, in which one or more ladder program files are stored.

Programmable

A characteristic of computers that allows them to perform widely varied tasks, depending on the instructions they receive through input commands or software programs

Prohibited condition

Any condition in a permit space that is not allowed by the permit during the period when entry is authorized.

Project

The entire contents of the memory of a PLC

Project Participants

Entities or individuals that agree to invest in and manage an oil and gas project. These may be private enterprises (including companies, individuals, and non-governmental organizations) or public entities.

Promoted Interest

Increased working interest gained by the assignor as a result of a farmout agreement. Traditionally, a farmout might stipulate that a latecomer who farms in must pay “1/3 for 1/4 working interest”, meaning they pay 33 1/3% of the costs but only earn a 25% working interest. The additional 8 1/3% represents a promoted interest for the original participant.

Promotor

A substance that is added to a regenerator to promote the combustion of carbon monoxide to carbon dioxide in the dense phase of the regenerator.

Prompt Gamma Rays

Prompt gamma rays are gamma rays emitted very quickly after the nucleus becomes excited.

Proof Burn

A stage of catalyst regeneration in which additional air is supplied to reactors in order to help ensure that all of the carbon deposits are burned off of the catalyst.

Propane

A three-carbon alkane (C3H8) of the paraffin series that is a gas at standard temperature and pressure but easily liquefied under pressure. Used as an LPG fuel, sent to refineries, or used as a petrochemical feedstock.

Propeller fan

A type of axial fan that consists of blades mounted on a hub; a shaft; and a drive motor. The blades are angled to lift, or catch, the air and move it along the shaft to the discharge side of the fan.

Proper respirator fit

A tight, leak-free seal between the wearer's face and a respirator mask or facepiece.

Property Insurance

Insurance policy carried by the oil or gas company that protects the owner of a property from loss or damage resulting from the company's operations.

Proportional Band

The error range over which a controller produces a control output proportional to the error. Narrow proportional band is equivalent to high controller gain. The inverse of controller gain, equal to change in input divided by change in output times 100%.

Proportional Control

A process control algorithm in which the output action is directly proportional to the difference between the input variable and its set point.

Proportional Solenoid

A solenoid that reacts proportionally to the electrical signal. As the electrical signal is increased, the energy in the solenoid increases at the same rate.

Proppant

A solid material (typically sand, treated sand, or man-made ceramic materials) designed to keep induced hydraulic fractures open during or following fracturing treatment so that oil and natural gas can flow through the fractures to the wellbore.

Proprietary System

A system that uses a standard defined by a specific vendor for connection of only that vendor's equipment. An example is Allen-Bradley's Data Highway Plus.

Propylene

A type of olefin commonly used in alkylation reactions; consists of three carbon atoms and six hydrogen atoms.

Prospect

A prospect is an area of exploration in which hydrocarbons have been predicted to exist in economic quantity. A prospect is commonly an anomaly, such as a geologic structure or a seismic amplitude anomaly that is recommended by explorationists for drilling a well.

Prospective Resources

Prospective resources are the quantities of petroleum estimated, at a given date, to be potentially recoverable from yet to be discovered (undrilled exploration prospects) accumulations. Prospective Resources have both an associated chance of discovery and a chance of development in the event of the exploration success case.

Protective Relay

A relay designed to quickly detect and isolate a fault.

Protective clothing

Clothing worn to prevent injury

Protective laboratory practices and equipment

Those laboratory procedures, practices, and equipment accepted by laboratory health and safety experts as effective, or that the employer can show to be effective, in minimizing the potential for employee exposure to hazardous chemicals.

Protective suit

Protective clothing made of materials that resist damage and prevent chemicals from soaking or burning through to the wearer's skin

Protocol

The rules applying to both network hardware and network data transmission procedures; devices connected on a common network need to operate according to the same protocol

Protofuel

A gasoline blend that has been tested in several labs against reference fuels to determine its octane number.

Proton

A stable subatomic particle with a positive electric charge equal in magnitude to the negative charge of an electron, with a mass slightly less than that of a neutron. Protons occur in all atomic nuclei.

Proton Resonance Frequency

Proton resonance frequency is a phenomenon in which protons absorb energy from an alternating magnetic field at certain characteristic frequencies when they are also subjected to a static magnetic field.

Protons

The proton is a subatomic particle with an electric charge of +1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons.

Proved developed reserves

Proved reserves that can be expected to be recovered through existing wells with existing equipment and operating methods or in which the cost of the required equipment is relatively minor compared to the cost of a new well.

Proved reserves

Proved oil and gas reserves are those quantities of oil and gas which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible - as defined by the U.S. Securities and Exchange Commission regulations and a typical company's Policy for Reserves Estimation, Accounting and Reporting.

Prover Loop Connections

The connections and valves on the LACT unit which provide easy connection of a volume prover for accuracy checking of the LACT meter.

Proximity Switch

An electronically activated switch that has the same function as a limit switch, but requires no physical contact with its actuator. Also called a "prox" switch.

Proximity work

Work that is performed near a hazard, but not actually in contact with hazard.

Pseudostatic Spontaneous Potential (PSP)

Pseudostatic spontaneous potential is the ideal spontaneous potential (SP) that would be observed opposite a shaly, permeable bed if the SP currents were prevented from flowing. In other conditions, however, the SP reads close to the pseudostatic spontaneous potential (PSP). Spontaneous potential (SP) refers to the natural electrical potential difference that arises in geologic al formations, primarily due to the movement of ions and differences in salinity between fluids.

Pseudostatic Spontaneous Potential, PSP

The pseudostatic spontaneous potential (PSP) is the ideal spontaneous potential that would be observed opposite a shaly, permeable bed if the SP currents were prevented from flowing. In the middle of a thick, permeable bed whose resistivity is not too high, the SP reads close to the pseudostatic spontaneous potential (PSP).

Pseudosteady State

Pseudosteady State is the period in which hydrocarbons in a reservoir flow in a steady state into the well. It can also be referred to as the “stabilized” flow condition from a bounded drainage area. In a pseudosteady flow, the pressure at various locations in the reservoir linearly declines as a function of time and remains constant at every point.

Psia

Pounds per square inch absolute. Equal to the gauge pressure plus the atmospheric pressure. Absolute pressure is pressure relative to zero or an absolute vacuum.

Psig

Pounds per square inch gauge. The pressure in a vessel or container as shown on the pressure gauge.

Puking

A condition in which excessive vapor pressure forces liquid up to the next tray level, and possibly out of the top of the column

Pulling a vacuum

A condition in which the pressure inside a tank becomes much lower than the pressure outside the tank; as a result, the tank may be crushed by the outside air pressure.

Pulsation

Periodic increases or decreases in pressure.

Pulse Counter

A device used in meter proving which counts the pulses generated by the meter.

Pulse Echo Mode

Pulse echo mode is a technique in which an ultrasonic transducer, in transmit mode, emits a high-frequency acoustic pulse towards the borehole wall, where it is reflected back to the same transducer operating in receive mode.

Pulse Signal

Signal such as steps and pubes that only occur once are called single-shot or transient signals. The pulse indicates what you would see if you turned a power switch on and then off again. A collection of pulses traveling together creates a pulse train.

Pulse Width Modulation

A method of producing the voltage required to drive a motor in a variable speed application.

Pulsed Neutron Capture Logging Tools

Pulsed Neutron Capture (PNC) logging tools are electronic logging devices that repeatedly generate very short bursts of high energy neutrons at an energy level of 14 MeV. Neutron capture is a type of nuclear reaction in which a target nucleus absorbs a neutron (uncharged particle), then emits a discrete quantity of electromagnetic energy (gamma-ray photon).

Pulsed Neutron Log

A pulsed neutron log uses induced gamma ray spectroscopy with a pulsed neutron generator. The elemental yields are derived from two intermediate results: the inelastic and the capture spectrum. The pulsed neutron log can indicate the oil saturation, but is affected by the formation water salinity, and the reservoir's lithology, porosity and clay content. The depth of investigation of the log is several inches into the formation. It can be run in open or cased hole.

Pulsed Neutron Spectroscopy Log

A wireline log of the yields of different elements in a formation, measured using induced gamma ray spectroscopy with a pulsed neutron generator. Elemental yields are derived from two intermediate results: the inelastic spectrum (basis for the carbon-oxygen log) and the capture spectrum (dependent on hydrogen, silicon, calcium, iron, sulfur, and chlorine).

Pulser Knob

A knob on some smart controllers that, when turned by a user, can reset a variable such as a setpoint, ratio, or bias

Pump Characteristic Curve

A graph curve that shows the relationship of two or more variables of pump operation, such as pressure and flow

Pump pit

A below-grade location for a pump in a tank farm.

Pump slab

An above ground location for a pump in a tank farm.

Pump-Arounds

Liquid streams from a distillation tower that are cooled in heat exchanger trains and then returned to the tower.

Pumped Off

The level of fluid in the well is lower than the position of the pump.

Pumping Tee

Surface connections to allow flow lines to be connected to the well head.

Purge

The process of removing vapors or contents from a vessel (such as an analyzer or sample cylinder) by filling and bleeding the entire contents.

Purging

A procedure for removing combustibles from a furnace

Pycnometer

A known volume and weight device used to prove the accuracy of a densitometer.

Pyrometer

A device used to measure temperature

Pyrophoric chemical

A chemical that will ignite spontaneously in air at a temperature of 130F or below

Pyrophoric material

Any material that is capable of igniting spontaneously when it is exposed to air or oxygen.

pH

A figure expressing the acidity or alkalinity of a solution on a logarithmic scale from 0 to 14, where 7 is neutral, lower values are more acid, and higher values are more alkaline.

pH Scale

A scale or method used to measure and indicate the relative acidity or alkalinity of a solution.

paleoslope

A paleoslope is a regional slope that can be identified by the direction of paleocurrents. Paleocurrents are the direction of sediment flow, which can be used to identify the orientation of shorelines, continental slopes, and submarine canyons.

paleostress

Paleostress is a stress, or stresses, that occurred in the geologic past

palinspastic

Palinspastic reconstruction is a technique used by geologists to change the geometry found on a seismic section to the geometry that existed at some prior geologic time. It is considered to be successful when the geologist has been able to account for all the volume of rock in the reconstructed geologic section.

paralic

Paralic facies are comprised of interfingering marine and continental sediments.

paravanes

A paravane in a seismic acquisition system that includes a float, a frame suspended from the float, deflectors affixed to the frame, means for coupling a tow rope and usually attached navigation and depth equipment.

passband

Passband is a specified range (or band) of frequencies through which a seismic signal may pass.

pelagic

Refers to the open ocean and the deposits or sediments that accumulate on the ocean floor, typically fine-grained, slowly deposited, and composed of biogenic material or wind-blown clays, far from land.

peneplains

Peneplains are low-relief plains that form by protracted fluvial erosion during times of extended tectonic stability.

petroleum systems

A petroleum system is a conceptual framework that defines the essential geologic elements and natural processes that generate and cause the accumulation and preservation of hydrocarbons. The system consists of five essential components: a source rock, a reservoir rock, a seal (or cap) rock, a trap and a migration pathway. Understanding these components and processes can assist with the search and production of petroleum.

phreatic zone

The phreatic zone, also known as the saturated zone or zone of saturation, is the part of an aquifer below the water table where the soil or rock is saturated with water. This is a reducing environment which preserves organic matter. Iron is also preserved as drab-colored ferrous oxides or pyrites.

piezoelectric

Piezoelectric refers to an electrical charge that accumulates in certain solid materials-such as crystals, certain ceramics, and biological matter (such as bone, DNA, and various proteins)-in response to an applied mechanical stress.

piezoelectric properties

Piezoelectric property refers to an electrical charge that accumulates in certain solid materials-such as crystals, certain ceramics, and biological matter (such as bone, DNA, and various proteins)-in response to an applied mechanical stress.

plagioclase

Plagioclase is a form of feldspar consisting of aluminosilicates of sodium and/or calcium, which is common in igneous rocks and typically appears white.

play or prospect

A play consists of one or more geologically related prospects, and a prospect is a potential trap that must be evaluated by drilling.

polycrystalline diamond compact (PDC)

A polycrystalline diamond compact (PDC) bit is a bit that uses synthetic diamond disks, called "cutters," to shear its way through rock with an ongoing scraping motion.

pre-spud

"Pre-spud" refers to activities that take place before the drilling rig begins the actual drilling of the borehole. Such activities include site preparation, move-in and set-up of the rig and associated equipment.

prodelta

A prodelta is the outermost, subaqueous portion of a delta, characterized by the deposition of fine-grained sediments, primarily silt and clay, that are carried by a river and settle at the base of the delta front. It is the most distal part of the delta, furthest from the river mouth, and is often affected by the influence of waves and tides.

productivity index (\( \small J \))

The productivity index represents the dynamic response of the reservoir and its fluid properties within the drainage area of a specific well. Each well has its own productivity index value, and each value applies to a specific average reservoir pressure.

prograding delta

A prograding delta is a coastline that is advancing toward the sea as a result of the accumulation of waterborne sediment

projection

Projection has to do with the angle at which the image was produced from the Satellite to the point on the Earth.

proof mass

A proof mass, or test mass, is a known quantity of mass used in a measuring instrument as a reference for the measurement of an unknown quantity.

pulse-echo mode

Pulse-echo mode is a technique in which an ultrasonic transducer, in transmit mode, emits a high-frequency acoustic pulse towards the borehole wall, where it is reflected back to the same transducer operating in receive mode.