Oil and Gas Terms Beginning with “G” — Page 5

A metal filter assembly used to support and retain the sand placed during gravel pack operations. A range of sizes and screen configurations is available to suit the characteristics of the wellbore, production fluid and… Read more →

A device used to measure the acceleration due to gravity, or, more specifically, variations in the gravitational field between two or more points. Read more →

The measurement of gravity or the study of its variations. Read more →

The Earth's gravitational field, or the attractive force produced by the mass of the Earth. Variations in the gravitational field can be used to map changes in the density of formations in the Earth. Gravity surveys can… Read more →

The difference between the actual value of gravity measured at a location and the value predicted by a particular Earth model. Gravity anomalies are usually determined by adjusting the known value of (absolute) gravity… Read more →

The least common primary recovery mechanism in which the force of gravity pushes hydrocarbons out of the reservoir, into the wellbore and up to surface.Gravity force is always present in the reservoir, but its effect is… Read more →

A phenomenon of multiphase flow in a reservoir in which a less dense fluid flows preferentially on the top of a reservoir unit and a more dense fluid flows at the bottom. For example, in a steamflood, steam flows on the… Read more →

The tendency of fluids to stratify into different layers because of gravity forces. In gravity segregation, the heaviest fluid settles near the bottom and the lightest fluid rises to the top. Gravity segregation occurs… Read more →

The measurement of gravitational acceleration over an area, usually presented as a map or profile of Bouguer or free-air anomalies. Read more →

One-tenth of a milliGal: (10 g.u. = 1.0 mGal). Gravity units are sometimes used in old gravity maps. Read more →

A frontal advance in which gravity and viscous forces are in equilibrium, resulting in a stable, highly efficient frontal advance. Read more →

An assembly of components used to contain wellhead fluids and pressure during braided-line or wireline operations. The wireline passes through a close-tolerance tube assembly as it leaves the wellbore. High-pressure… Read more →

The action in which mud particles (barite) become coated with an oily substance that causes the particles to agglomerate. This can cause barite settlement or removal by shaker screens. The problem can occur when mud… Read more →

A mathematical procedure used to improve computer usage in simulated annealing runs. The procedure uses a fast swapping technique to match model semivariograms to actual semivariogram data. Read more →

Untreated gas that leaves the well. This gas could contain impurities such as water, carbon dioxide [CO2], nitrogen [N2] and hydrogen sulfide [H2S], which will be removed in treating facilities. Read more →

To convert irregularly spaced points to a regular spacing by interpolation. Read more →

The act of determining values for grid elements on a map. The grid element values are chosen from nearby data points. Methods are deterministic and use linear and nonlinear interpolation methods, or may be statistical… Read more →

A computational procedure incorporated in methods for determining the values to be assigned to grid elements on a map. The deterministic gridding algorithms are mostly simpler interpolation; the stochastic approaches… Read more →

The fineness to which cement is ground. Grind also may refer to a specific production of cement, such as the lot number. Read more →

The profiled blocks attached to the drive chains of a coiled tubing injector head. The gripper blocks are arranged in opposing pairs to secure the coiled tubing string in the injector-head chains. As the hydraulic drive… Read more →

The total production of oil, gas or water from a well or field over a specific period of time. Read more →

A type of coherentnoise generated by a surface wave, typically a low-velocity, low-frequency, high-amplitude Rayleigh wave. Ground roll can obscure signal and degrade overall data quality, but can be alleviated through… Read more →

Water in the subsurface below the water table. Groundwater is held in the pores of rocks, and can be connate, from meteoric sources, or associated with igneous intrusions. Read more →

A set of seismometers whose output is sent to a common data channel to record a seismic trace. A large group is known as a patch. Read more →

The distance between geophones or groups of geophones. Read more →

A type of normal fault that develops and continues to move during sedimentation and typically has thicker strata on the downthrown, hanging wall side of the fault than in the footwall. Growth faults are common in the… Read more →

A hydrophilic polysaccharide from the seed of the guar plant. It is a galactomannan type of saccharide that is highly dispersible into water and brines of various types and salinity. Its water solutions are… Read more →

An electrode on a laterolog sonde that focuses the current sent by the central current-emitting electrode (A0). The guard electrode is held at the same potential as A0, thereby forcing the current from A0 to run… Read more →

A measurement made by a type of electrode device in which the current flow and hence the measurement is focused in a disk that is concentric with and perpendicular to the sonde. The term usually refers to a Laterolog-3… Read more →

A tapered, often bullet-nosed piece of equipment often found on the bottom of a casing string. The device guides the casing toward the center of the hole and minimizes problems associated with hitting rock ledges or… Read more →