Oil and Gas Terms Beginning with “P” — Page 9

What Is a Pressure Gradient? Pressure gradient (also called fluid gradient or hydrostatic gradient) is the change in fluid pressure per unit depth in the subsurface, expressed in pounds per square inch per foot (psi/ft)… Read more →

What Is a Pressure Hunt? A pressure hunt is a formation pressure testing procedure in which the wireline formation tester tool (MDT, RFT, FMT) is pressed against the borehole wall at a potential reservoir zone and a… Read more →

The sensor component in a system used to measure and display the pressure within a vessel or system. The pressure sender may be hydraulically or electrically connected to a remote gauge or display. Read more →

A pressure storage tank is a closed vessel designed to contain liquid hydrocarbons, produced water, or process fluids at pressures above atmospheric, typically ranging from a few pounds per square inch gauge (psig) to… Read more →

A pressure transient test (PTT) is a well testing methodology that analyzes how wellbore pressure changes over time in response to a deliberate change in production or injection rate — using the pressure response… Read more →

A pressure transient well test is a reservoir evaluation method in which the wellbore pressure response to a controlled, deliberately imposed change in flow rate (buildup, drawdown, injection falloff, or interference… Read more →

A pressure-composition (P-x or P-xy) diagram is a phase equilibrium plot that shows the states of matter present in a binary or multicomponent mixture as a function of both pressure and composition at a fixed… Read more →

What Is Pressure Drawdown Analysis? Pressure drawdown analysis (also called a drawdown test or flowing pressure transient test) is a well test method in which a well that has been shut in long enough to reach static… Read more →

A pressure-squared plot is a graphical analysis method used in gas well testing and deliverability evaluation in which the square of the wellbore flowing pressure (p_wf²) is plotted against the square of the static… Read more →

What Is Pressure Transient Analysis? Pressure transient analysis (PTA) is the interpretation of pressure changes in a well and reservoir caused by deliberate rate changes — production, injection, or shut-in — to… Read more →

Pressure transient well tests are a family of diagnostic measurements that analyze the behavior of reservoir pressure as it responds to deliberate changes in well flow rate — specifically the way a pressure disturbance… Read more →

A pressurized mud balance is a specialized drilling fluid density measurement instrument used to accurately determine the unit weight (density) of drilling muds and completion fluids that contain entrained gas or gas… Read more →

Primary cementing is the first cementing operation performed on a well, in which a cement slurry is pumped down the inside of a casing or liner string and displaced upward through the annular space between the outside… Read more →

Primary completion components are the fundamental downhole and wellhead hardware elements installed during the initial well completion to establish the conduit for reservoir fluid production, provide pressure… Read more →

The expulsion of newly generated hydrocarbons from a source rock. The further movement of the hydrocarbons into reservoir rock in a hydrocarbon trap or other area of accumulation is secondary migration. Read more →

The porosity preserved from deposition through lithification. Read more →

(noun) The first stage of hydrocarbon recovery in which oil and gas are produced using the natural energy of the reservoir, including solution gas drive, gas cap expansion, water drive, gravity drainage, and rock and… Read more →

What Is Primary Recovery? Primary recovery is the first stage of hydrocarbon production, in which natural reservoir energy — gas drive, water drive, gas cap expansion, compaction drive, or gravity drainage — displaces… Read more →

Primary recovery is the first phase of oil and gas production, in which fluid is produced using only the natural energy already stored in the reservoir. That energy comes from the pressure in the reservoir rock and the… Read more →

A primary reflection in seismic exploration is a seismic event generated when a portion of the downward-traveling wavefield from the source reflects off a subsurface acoustic impedance contrast (an interface between… Read more →

The primary term in an oil and gas lease is the initial fixed period of time (typically ranging from one to ten years, most commonly three to five years for exploration leases in mature basins and up to ten years for… Read more →

A prime mover is the primary power source on a drilling rig that converts chemical energy from diesel or natural gas combustion, or electrical energy from the grid or generators, into mechanical shaft power to drive the… Read more →

(noun) A flexible, rope-like explosive charge consisting of a core of PETN or RDX explosive within a textile or plastic outer sheath, used to transmit a detonation signal between perforating charges, boosters, or other… Read more →

A principal axis in multivariate statistical analysis is the directional axis along which data points in n-dimensional measurement space are primarily distributed — capturing the dominant pattern of data variation… Read more →

Principal component analysis (PCA) is a statistical dimensionality-reduction technique that transforms a set of correlated variables into a smaller set of uncorrelated variables called principal components, each of… Read more →

A numerical estimate of the chances of an event occurring given a limited number of opportunities for the event to occur. Read more →

A probe in oil and gas operations refers to two distinct but related concepts: in electromagnetic (EM) geophysical methods, a probe is a downhole measurement device or surface sensor used to record the variation of an… Read more →

Seismic processing is the sequence of computational steps applied to raw seismic field data — the digitally recorded ground motion measurements from geophones or hydrophones — to transform them into interpretable… Read more →

Produced fluid is a generic term encompassing all fluids that flow from the subsurface formation through the wellbore and to the surface during oil and gas production, including the target hydrocarbon phases (crude oil,… Read more →

Produced water is the water that is extracted from the subsurface along with oil and natural gas during petroleum production operations, consisting of formation water (connate water that has been present in the… Read more →