Oil and Gas Terms Beginning with “P” — Page 4

A perforating depth-control log is a wireline log run before a perforating job to confirm exactly where the perforating gun will fire relative to the geological zones the operator wants to perforate. The log compares… Read more →

Perforating fluid is the wellbore fluid present in the completion interval at the time of perforation gun detonation, occupying the casing, tubing, and perforating gun annulus and potentially invading the near-wellbore… Read more →

What Is a Perforating Gun? Perforating gun (also called a perforation gun or perf gun) is a downhole tool consisting of a carrier body loaded with shaped explosive charges that is deployed into the wellbore on wireline,… Read more →

What Is Perforation? Perforation is the engineered communication tunnel through steel casing , cement sheath, and into the reservoir formation that establishes the primary flow path between the producing interval and… Read more →

What Is Perforation Density? Perforation density measures the number of perforating-gun shots per linear foot or per metre of casing, expressed in shots per foot (spf) or shots per metre (spm). Completion engineers… Read more →

Perforation penetration in well completion is the depth to which the jet from a shaped explosive charge in a perforating gun extends into the formation beyond the casing and cement, creating the flow channel through… Read more →

What Is Perforation Phasing? Perforation phasing (also called gun phasing or shot phasing) is the angular orientation between successive perforations around the circumference of the casing, measured in degrees. It is… Read more →

A periodogram is a frequency-domain graphical representation of the variance of a time series or depth series, computed by taking the squared magnitude of the discrete Fourier transform (DFT) of the sampled signal and… Read more →

What Is Permafrost? Permafrost (also called pergelisol or permanently frozen ground) is subsurface earth material, including soil, sediment, or rock, that remains at or below 0 degrees Celsius for at least two… Read more →

A permanent datum in oil and gas well operations is a fixed, precisely surveyed reference elevation point established at or near the wellhead that serves as the consistent vertical reference for all depth measurements,… Read more →

What Is Permanent Well Monitoring? Permanent well monitoring is the continuous, real-time acquisition of downhole pressure, temperature, flow rate, and fluid composition data through sensors permanently installed in the… Read more →

What Is Permeability? Permeability quantifies a rock's capacity to transmit fluids under a pressure gradient, governing how readily oil, gas, or water moves through interconnected pore spaces in a reservoir. Defined… Read more →

What Is Permeability Thickness? Permeability thickness (also written as the kh product) is the arithmetic product of a formation's average effective permeability and its net pay thickness, quantifying the total flow… Read more →

A permeameter is a laboratory instrument that measures the permeability of a rock sample by flowing a fluid (gas or liquid) through the sample at a controlled differential pressure and measuring the resulting flow rate,… Read more →

Perpendicular offset is the horizontal or slant distance measured perpendicularly from a source point to a receiver line (or from a receiver point to a source line) in a geophysical survey, representing the closest… Read more →

The resistivity of a formation measured by flowing current perpendicular to the bedding planes. In anisotropic formations, the parallel and perpendicular resistivities are different. Read more →

(noun) A production logging tool consisting of a flexible, flower-shaped metal basket that expands against the casing or tubing wall to divert all fluid flow through a central spinner or sensor, providing a full-bore… Read more →

Petrography is the branch of geology concerned with the systematic description, classification, and interpretation of rocks based on their mineralogy, texture, fabric, and microstructure, typically using optical… Read more →

Petroleum is a naturally occurring mixture of hydrocarbons found in geological formations beneath the earth's surface, encompassing crude oil (liquid hydrocarbons at surface conditions), natural gas (gaseous… Read more →

What Is a Petroleum System? Petroleum system (also called a hydrocarbon system or charge system) is the geologic framework encompassing all elements and processes required for the generation, migration, accumulation,… Read more →

What Is Petroleum Systems Modeling? Petroleum systems modeling (PSM, also called basin modeling) is the quantitative simulation of the geological processes that generate, expel, migrate, and accumulate hydrocarbons over… Read more →

Petrology is the systematic study of rocks, examining their origin, composition, texture, structure, and geological history through both field observation and laboratory analysis. In the oil and gas industry, petrology… Read more →

A model of a reservoir or a field in which the petrophysical data were the only or the primary data used to construct the model. Read more →

What Is a Petrophysical Rock Type? Petrophysical rock type (also called hydraulic flow unit, reservoir rock type, or PRT) is a classification of reservoir rock intervals that groups core or log data into discrete… Read more →

A phantom, also called a phantom horizon, is a seismic interpretation device representing the presumed continuation of a reflection event across a zone where that event cannot be directly picked. In areas of… Read more →

What Is Phase? In oil and gas, the term phase carries two distinct technical meanings depending on context: in seismic data acquisition and processing, phase refers to the timing and polarity relationship of a seismic… Read more →

Phase redistribution is the process by which the proportions and spatial distribution of multiple fluid phases (gas, oil, and water) within a wellbore change over time when the well is shut in, stopped from flowing, or… Read more →

Phase shift in petroleum geophysics and well logging refers to the difference in phase (timing) between two measurements of the same wave phenomenon — most commonly applied in resistivity logging (where the phase shift… Read more →

Phase-shift resistivity is a propagation resistivity measurement derived from the phase difference between two receiver coils on an LWD/MWD tool, where an electromagnetic wave transmitted at 2 MHz or 400 kHz is… Read more →

What Is a Phase-Velocity Log? A phase-velocity log is an electromagnetic propagation resistivity measurement that derives formation resistivity from the phase shift of a propagating electromagnetic wave between two… Read more →