Oil and Gas Terms Beginning with “G” — Page 2

Hydrocarbon gas density expressed as the ratio of the molecular weight of the gas to the molecular weight of air. Read more →

What Is a Gas Hydrate? A gas hydrate is a crystalline solid clathrate compound in which water molecules form a hydrogen-bonded lattice cage that traps small gas molecules, principally methane, under conditions of low… Read more →

Gas that is dissolved in a liquid, such as water or oil. Read more →

A reservoir maintenance or secondary recovery method that uses injected gas to supplement the pressure in an oil reservoir or field. In most cases, a field will incorporate a planned distribution of gas-injection wells… Read more →

A phenomenon that occurs when gas enters the subsurface sucker-rod pump. After the downstroke begins, the compressed gas reaches the pressure needed to open the traveling valve before the traveling valve reaches liquid.… Read more →

What Is Gas Lift? Gas lift is an artificial lift method that injects compressed gas down the casing-tubing annulus and into the production tubing through a series of gas lift valves, aerating the produced fluid column… Read more →

A condition sometimes encountered in a pumping well when dissolved gas, released from solution during the upstroke of the plunger, appears as free gas between the valves. On the downstroke, pressure inside a barrel… Read more →

A generic term referring to all possible routes for annular gas entry and propagation through and around the cement sheath. Gas migration is also known as annular gas flow. Read more →

An installation that processes natural gas to recover natural gas liquids (condensate, natural gasoline and liquefied petroleum gas) and sometimes other substances such as sulfur. A gas processing plant is also known as… Read more →

A poroussandlayer or sand body charged with natural gas. Read more →

A device used to separate entrained gas from production liquids. Surface processing facilities generally use gas separators to render the liquids safe for further processing or disposal. Gas-separation equipment is also… Read more →

Gas that rises to the surface, usually detected because it reduces the density of the drilling mud. Gas detectors, which the mud logger monitors, measure combustible gases (methane, ethane, butane and others). The mud… Read more →

A producing well with natural gas as the primary commercial product. Most gas wells frequently produce some condensate (natural gas liquids such as propane and butane) and occasionally produce some water. Read more →

Relating to a formation or interval containing gas, either dissolved in the formation fluid or as free gas. The term is occasionally used to describe wellbore fluids containing dissolved gas. Read more →

A type of reservoir-drive mechanism in which the energy for the transport and production of reservoir fluids is provided by the expansion of gas either in the gas cap or inside the oil phase. Read more →

A mud that has gas (air or natural gas) bubbles in it. Defoamer chemicals added to the mud or a mechanical vacuum pump degasser can liberate the trapped gas. When weighed with a regular mud balance, a gas-cut mud has… Read more →

A record of the fraction of gas present at different depths in the borehole. Although several techniques may be used for this purpose, the term usually refers to logs based on one of two principles. In the first, four… Read more →

A gas-lift system component that is assembled with the production tubing string to provide a means of locating gas-lift valves. The position or depth of the gas lift valves is crucial to the efficient operation of the… Read more →

A valve used in a gas-lift system to control the flow of lift gas into the production tubing conduit. The gas-lift valve is located in the gas-lift mandrel, which also provides communication with the lift gas supply in… Read more →

A bounding surface in a reservoir above which predominantly gas occurs and below which predominantly oil occurs. Gas and oil are miscible, so the contact between gas and oil is transitional, forming a zone containing a… Read more →

The interface between the gas and oil phases present in a reservoirformation. During the production of a well, the GOC may move, resulting in undesirable production conditions such as a high proportion of gas that may… Read more →

The quality of a source rock that makes it more likely to generate gas than oil. The nature of the organic matter or kerogen in source rocks varies from coaly, plant-like material commonly found in terrestrial source… Read more →

The volume of gas (at standard conditions) liberated from a volume of oil (at standard conditions). Read more →

A bounding surface in a reservoir above which predominantly gas occurs and below which predominantly water occurs. Gas and water are somewhat miscible, so the contact between gas and water is not necessarily sharp and… Read more →

The calculated or measured rate a gas well will produce for a given bottomhole or wellheadpressure. Read more →

The ratio of produced gas to produced liquids (oil and water), often abbreviated GLR. Read more →

What Is Gas-Oil Ratio (GOR)? The gas-oil ratio (GOR) is the volume of gas produced per unit volume of oil at standard surface conditions, expressed in standard cubic feet per barrel (scf/bbl) in the United States or… Read more →

The gas produced or separated at surface conditions from the full well stream produced from a natural gas reservoir. Read more →

The liquids separated at surface conditions from the full well stream produced from a natural gas reservoir. Read more →

A type of valve that incorporates a sliding gate to block fluid flow. The design of the valve operating and sealing systems typically requires that gate valves should be operated either fully open or fully closed. Read more →