Lexicon of Terms

Learn how to talk like an Oilman
417 Oil & Gas and related investment terms defined.
Geophysicist — A geophysicist applies the principles of physics to the understanding of geology.

Gamma-ray logging — A technique of exploration for oil in which a well's borehole is irradiated with gamma rays. The varying emission of these rays indicates to geologists the relative density of the rock formation at different levels.

Gun perforation — A method of creating holes in a well casing downhole by exploding charges to propel steel projectiles through the casing wall. Such holes allow oil from the formation to enter the well.

Geophones — The sound-detecting instruments used to measure sound waves created by explosions set off during seismic exploration work.

General partner — In a limited partnership, the general partner is responsible for managing the partnership's activities (and is commonly the party that put the deal together). His liability to the partnership's creditors is limited.

Geothermal energy — Energy produced from subterranean heat.

Gas-oil ratio — The number of cubic feet of natural gas produced along with a barrel of oil.

Gas-cut mud — Drilling mud permeated with bubbles of gas from downhole. The circulation of such mud can be severely impaired, seriously affecting drilling operations.

Gusher — A well drilled into a formation in which the crude is under such high pressure that at first it spurts out of the wellhead like a geyser. Gushers are rare today owning to improved drilling technology, the use of drilling mud to control downhole pressure, and oilmen's recognition of their wastefulness.

Gross income — Total income from an activity, before deduction of (1) items that may be treated as expenses (such as intangible drilling costs), and (2) allowed tax items (such as depletion allowance, depreciation allowance, etc.).

Gas condensate — Liquid hydrocarbons present in casinghead gas that condense when brought to the surface.

Gas lift — A recovery method that brings oil from the bottom of a well to the surface by using compressed gas. Gas pumped to the bottom of the reservoir mixes with fluid, expands it, and lifts it to the surface.

Gas cap — The gas that exists in a free state above the oil in a reservoir.

Gravimeter — A geophysical device that has been particularly useful in finding salt domes. Actually, it is a weight on a spring. The spring gets longer in high-gravity areas and shorter in areas of gravity-minus. Magnetism helps the oil geologist understand its measurements

Gasoline — A volatile, inflammable, liquid hydrocarbon mixture.

Guaranteed payments — Payments by a partnership to one or more of its partners for services rendered.

Groundwater — The water in underground rock strata that supplies wells and springs.


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