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

A change in pressure as a function of distance. This can refer to radial change in pore pressure with distance from the well (which can be calculated from well-test analysis results), to change in pore pressure with… Read more →

The evaluation of various well parameters in an attempt to identify when the pore pressure in a drilling well is changing. A team consisting of geologists, engineers and most of the rigsite personnel usually conducts… 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 tank designed for storing volatile liquids such as gasoline and liquefied petroleum gases (LPG), which generate high internal pressures. A pressure storage tank is commonly spherical. Other types include spheroidal or… Read more →

A means of assessing reservoir performance by measuring flow rates and pressures under a range of flowing conditions and applying the data to a mathematical model. Fundamental data relating to the interval under test,… Read more →

A means of assessing reservoir performance by measuring flow rates and pressures under a range of flowing conditions and then applying the data to a mathematical model. In most well tests, a limited amount of fluid is… Read more →

A graphical representation indicating phase behavior for variation of saturationpressure and injection gas concentration at a given temperature. The diagram indicates conditions for single-phase and two-phase behavior… Read more →

The analysis of pressure-transient behavior observed while the well is flowing. Results are generally much less accurate than those from pressure buildup tests because the bottomhole pressure fluctuates rapidly with… Read more →

A plot of p2 versus time function used to analyze low-pressure gas-well drawdown and buildup tests. The square term arises from substituting a gas-law equation into the differential equations where required to account… 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 →

Well tests in which pressure is recorded as a function of time and interpreted using various analysis methods. These include buildup tests and drawdown tests in production wells and falloff tests in injection wells.… Read more →

A device to measure density (weight) of a mud, cement or other liquid or slurry under sufficient pressure that the effect of gas bubbles in the liquid is eliminated. The balance consists of a fixed-volume mud cup on one… Read more →

The first cementing operation performed to place a cement sheath around a casing or liner. The main objectives of primary cementing include zonal isolation to prevent fluid migration in the annulus, support for the… Read more →

The main elements of an oil or gas well, including the production tubing string, that enable a particular type or design of completion to function as designed. The primary completion components depend largely on the… 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 →

The means by which the initial reservoirproduction is achieved, such as natural production from a gas-drive reservoir. In many cases, a secondary recovery method, such as waterflood, is required to maintain a viable… Read more →

Seismic events whose energy has been reflected once. Multiples, in contrast, are events whose energy has been reflected more than once. A goal of seismic data processing is to enhance primary reflections, which are then… Read more →

The period of time during which an oil and gas lease will be in effect, in the absence of production, drilling or other operations specified by the lease. The oil and gas lease can be perpetuated past the primary term… Read more →

The source of power for the rig location. On modern rigs, the prime mover consists of one to four or more diesel engines. These engines commonly produce several thousand horsepower. Typically, the diesel engines are… 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 →

The axis along which the data in n-dimensional space is primarily distributed. In two dimensions, the first principal axis is the semimajor axis of the ellipse that best fits the data set. Multiple principal axes are… Read more →

Analysis of data that has been transformed from the original axes to principal axes, often abbreviated PCA. The first principal axis is the direction in which the data are primarily distributed or the "long" axis of the… 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 →

In electromagnetic methods, to measure the variation of a property versus depth, including electrical, electromagnetic and magnetotelluric properties. Probing differs from profiling in that the goal of probing is to… Read more →

Alteration of seismic data to suppress noise, enhance signal and migrate seismic events to the appropriate location in space. Processing steps typically include analysis of velocities and frequencies, static… Read more →

A generic term used in a number of contexts but most commonly to describe any fluid produced from a wellbore that is not a treatment fluid. The characteristics and phase composition of a produced fluid vary and use of… Read more →

A term used to describe water produced from a wellbore that is not a treatment fluid. The characteristics of produced water vary and use of the term often implies an inexact or unknown composition. It is generally… Read more →