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That state of matter which has neither independent shape nor volume. It expands to fill the entire container in which it is held. It is one of the three forms of matter, the other two being solid and liquid.
Gas Absorption
The extraction of a gaseous substance from an atmosphere by liquid or solid material.
Gas Bag
A gas-proof, inflatable bag which can be inserted in a gas pipe and inflated to seal off the flow of the gas.
Gas Balance Report
A monthly accounting report containing month-end meter station allocations for each customer/shipper contract. The report may be sorted by meter station or by contract.
Gas Bubble
An excess of natural gas deliverability relative to demand requirements at current prices.
Gas Cap
A layer of free gas on top of the oil zone in an underground structure or reservoir.
Gas Central Furnace and Boiler Efficiency Measures
The annual efficiency ratings of furnaces and boilers based on average usage, including on and off cycling as determined by standardized Department of Energy test procedures.
Gas Conditioning
The removal of objectionable constituents and addition of desirable constituents.
Gas Controller
A person or persons assigned the task of monitoring and controlling daily gas system operations and ensuring safety of a pipeline or distribution system.
Gas Cycling
A petroleum recovery process which takes gas produced with condensate and injects it back into the reservoir to aid in producing more condensate. See REPRESSURING.
Gas Day
A period of twenty-four (24) consecutive hours commencing at a specified hour on a given calendar day and ending at the same specified hour on the next succeeding calendar day.
Gas Detector
A device which indicates the existence of combustible or noxious gas.
Gas Generator
The section of a gas-turbine that provides the high temperature gases needed to drive the power turbine.
Gas Imbalance
a. Producer/Producer - When one or more producers sell or utilize a volume of natural gas in excess of their gross working interest. b. Pipeline/Pipeline - When a pipeline receives a volume of natural gas and redelivers a larger or smaller volume of natural gas under the terms of a transportation agreement. c. Producer/Pipeline - When a producer delivers a volume of natural gas that is larger or smaller than the volume of natural gas that the pipeline redelivers for the producer's account to another party.
Gas Impurities
Undesirable matter in gas, such as dust, excessive water vapor, hydrogen sulphide, tar, and ammonia.
Gas in Place (GIP)
The amount of gas in a reservoir at any time, calculated at standard conditions. This includes recoverable and nonrecoverable gas.
Gas Injection
Gas Inventory Charge (GIC)
A forward-looking mechanism for the current recovery of take-or-pay costs, established in Commission Order No.500. Section 2.105 sets forth the general guidelines for GICs. The GIC is intended to recover costs, on a current basis, associated with contractually committing gas service tailored to meet the customer's nominations. GIC's generally fall into two categories. Some GIC's are cost based, that is, they are designed to recover certain identified costs, subject to a reconciliation mechanism. Other GIC's are market based or market responsive. Market Based GIC commodity charges are based upon a measure of the current market price for gas. Market Based GIC demand charges are generally designed to recover any premiums which must be paid above the current market price for long term gas supply commitments. GIC charges generally are assessed either based on a customer's nominated contract demand (Demand Based GIC) or on the amount by which the customer's takes are less than a percentage of its nominations (Deficiency Based GIC). Prior to receiving authority to implement a Market Based GIC mechanism, the Commission must first find that the pipeline is operating in a market that is sufficiently competitive and that the pipeline's firm transportation service is comparable in quality to its firm sales service. See COMPARABILITY OF SERVICE.
Gas Lift
The effect of gas pressure in an oil well which causes the oil to flow from the well. May be either natural or artificially induced by injecting gas into the hole under pressure. Below the surface, gas intermixes with the oil, lightens the oil column, and allows it to flow.
Gas Plant
Any plant which performs one of the following functions: removing liquefiable hydrocarbons from wet gas or casinghead gas (gas processing); removing undesirable gaseous and particulate elements from natural gas (gas treatment); removing water or moisture from the gas stream (dehydration). Also, the original cost of property, plant and equipment owned and used by the utility in its gas operations and having an expectation of life in service of more than one year from the date of installation.
Gas Research Institute (GRI)
An organization sponsored by a number of U.S. gas companies to investigate new sources of supply and new uses (applications) for natural gas.
Gas Sand
The underground porous strata which contains natural gas and from which it is produced. "Sand" as used here is a generic term that may denote a porous limestone or dolomite, as well as a sandstone or unconsolidated sand formation.
Gas Supply Coordinator
A representative of a company assigned the task of managing the operations under Transportation, Sales or Purchase Service agreements. Responsibilities typically include scheduling activity, imbalance management and volume confirmation.
Gas Transported for Others
That volume of gas owned by another company received into and transported through any part of the transmission or distribution system under a transportation tariff.
Gas Turbine
A prime mover in which gas, under pressure or formed by combustion, is directed against a series of turbine blades; the energy in the expanding gas is converted into mechanical energy supplying power at the shaft.
Gas Used
The total quantity of gas used by the transmission or distribution company in the operation (i.e., fuel), the maintenance and the construction of facilities.
Gas Well
Gas Zone
A porous, permeable formation containing natural gas under pressure. Compare STORAGE, UNDERGROUND.
A set of standard record formats supporting the electronic data interchange of the documents described in the Nominations/Allocations Subcommittee and the Volume Imbalance Subcommittee reports.
Gas, Associated
Free natural gas in immediate contact, but not in solution, with crude oil in the reservoir.
Gas, Associated
Gas produced in association with oil, or from a gas cap overlying and in contact with the crude oil in the reservoir. In general, most states restrict associated gas production since its indiscriminate production could reduce the ultimate oil recovery. Also, since some wells producing associated gas cannot be shut-in without also shutting-in the oil production, natural gas pipelines are generally required to take allowed associated gas produced from oil wells on a priority basis. See also GAS CAP.
Gas, Blast Furnace
Gas obtained from blast furnaces. It is low in heat content.
Gas, Casinghead
Gas produced with oil in oil wells. The gas being taken from the well through the casinghead at the top of the well.
Gas, Conventional
Gas that can be produced with current technology at a cost that is no higher than its current market value.
Gas, Dissolved
Natural gas in solution in crude oil in the reservoir.
Gas, Dry
Gas, Extraneous
Gas, Field
A district or area from which natural gas is produced.
Gas, Flue
The products of combustion and excess air before the draft hood or draft regulator consisting principally of carbon dioxide, carbon monoxide, oxygen, and nitrogen.
Gas, Foreign
Gas, Illuminating
A gas containing relatively large amounts of unsaturated and/or heavy hydrocarbon gases which burn with a luminous flame.
Gas, Liquefied Petroleum (LPG)
A gas containing certain specific hydrocarbons which are gaseous under normal atmospheric conditions but can be liquefied under moderate pressure at normal temperatures. Propane and butane are the principal examples.
Gas, Manufactured
A gas obtained by destructive distillation of coal, or by the thermal decomposition of oil, or by the reaction of steam passing through a bed of heated coal or coke, or catalyst beds. Examples are coal gases, coke oven gases, producer gas, blast furnace gas, blue (water) gas, and carbureted water gas. Btu content varies widely.
Gas, Natural
A naturally occurring mixture of hydrocarbon and nonhydrocarbon gases found in porous geologic formations beneath the earth's surface, often in association with petroleum. The principal constituent is methane. 1. Dry. Gas whose water content has been reduced by a dehydration process. Gas containing little or no hydrocarbons commercially recoverable as liquid product. Specified small quantities of liquids are permitted by varying statutory definitions in certain states. 2.Liquefied (LNG). See LIQUEFIED NATURAL GAS. 3. Sour. Gas found in its natural state, containing such amounts of compounds of sulfur as to make it impractical to use, without purifying, because of its corrosive effect on piping and equipment. 4.Sweet. Gas found in its natural state, containing such small amounts of compounds of sulfur that it can be used without purifying, with no deleterious effect on piping and equipment. 5. Wet. Wet natural gas is unprocessed natural gas or partially processed natural gas produced from strata containing condensable hydrocarbons. The term is subject to varying legal definitions as specified by certain state statutes. (The usual maximum allowable is 7lbs./MMcf water content and .02 gallons/Mcf of Natural Gasoline.)
Gas, Non-Associated
Free natural gas not in contact with, nor dissolved in, crude oil in the reservoir.
Gas, Oil
A gas resulting from the thermal decomposition of petroleum oils, composed mainly of volatile hydrocarbons and hydrogen. The true heating value of oil gas may vary between 800 and 1600 Btu per cubic foot depending on operating conditions and feedstock properties.
Gas, Sour
Gas, Stack
Gas, Sweet
Gas, Synthesis
A mixture of CO and H2 containing small amounts of nitrogen, some carbon dioxide, and various trace impurities prepared for petrochemical synthesizing processes. It is also used in the manufacturing of SNG.
Gas, Unconventional
Gas that can not be economically produced using current technology.
Gas, Vent
Products of combustion from gas appliances plus excess air plus dilution air in the gas vent or chimney above the draft hood or draft regulator.
Gas, Waste
Gas, Wet
Gas-Oil Ratio
The quantity of gas produced with oil from an oil well, usually expressed as the number of cubic feet of gas produced per barrel of oil produced.
The conversion of carbonaceous material into gas or the extraction of gas from another fuel.
The process during which liquified natural gas (LNG) is returned to its vapor or gaseous state through an increase in temperature and a decrease in pressure.
Gasoline Plant
A plant in which hydrocarbon components common to the gasoline fractions are removed from "wet" natural gas, leaving a "drier" gas. See EXTRACTION PLANT.
Gate Station
Generally a location at which gas changes ownership, from one party to another, neither of which is the ultimate consumer. It should be noted, however, that the gas may change from one system to another at this point without changing ownership. Also referred to as city gate station, town border station, or delivery point.
A legal entity which has responsibility for the collection of the gas from the wellhead and the delivery of that gas to either a gas plant or a pipeline.
The act of operating extensive low-pressure gas lines which aggregate the production of several separate gas wells into one larger receipt point into an interstate pipeline.
Gathering Agreement
Agreement between a producer and a gathering system operator specifying the terms and conditions for entry of the producer's gas into the gathering system.
Gathering Line
A pipeline, usually of small diameter, used in gathering gas from the field to a central point.
Gathering Station
A compressor station at which gas is gathered from wells by means of suction because pressure is not sufficient to produce the desired rate of flow into a transmission or distribution system.
Gathering System
The gathering pipelines plus any pumps, tanks, or additional equipment used to move oil or gas from the wellhead to the main pipeline for delivery to a processing facility or consumer.
Gauge, Pressure
Instrument for measuring the relative pressure of a fluid. Types include gauge, absolute, and differential.
General Plant
A group of utility plant accounts not includible in the other functional utility plant accounts. Includes: Land and Land Rights, Structures and Improvements, Office Furniture and Equipment, Transportation Equipment, Stores Equipment, Tools, Shop and Garage Equipment, Laboratory Equipment, Power Operated Equipment, Communication Equipment, Miscellaneous Equipment, and Other Tangible Property.
General System Supply
Gas that is purchased by a pipeline or distribution company for the purpose of resale. See SYSTEM SUPPLY.
Generation, Non-Utility
Generation by producers having generating plants for the purpose of supplying electric power required in the conduct of their industrial and commercial operations. Generation by mining, manufacturing, and commercial establishments and by stationary plants of railroads and railways for active power is included.
Geophysical Survey
Searching and mapping of the subsurface structure of the earth's crust by use of geophysical methods, to locate probable reservoir structures capable of containing gas or oil.
A study of subsurface geological conditions of structure or material through the interpretation of measurement variations in density, magnetics, elasticity, electrical conductivity, temperature, and/or radioactivity.
Geopressured Brines
Saltwater found in underground formations in which the pressure is much higher than commonly exists at such depths (primarily in the Gulf Coast states and under the Gulf of Mexico). Gas is soluble in water, just as it is in crude oil, but in much lower amounts. Solubility increases with pressure. Geopressured brines (with formation pressures of 10,000 psi or higher) contain sufficient gas in solution that were the pressure reduced (by producing the saltwater) significant quantities of gas could be produced. The total amount of gas held in geopressured brines is quite large and represents a potential energy resource for the U.S. However, the production of such gas is currently not economic.
See PIG.
Golden Rule
Certain parties have advanced the concept of the "Golden Rule" in pipeline rate cases. Under this concept, the pipeline as a merchant must be subject to all of the terms and conditions as other shippers on the pipeline's system. The pipeline, as a merchant, must contract with itself for transportation service and receive a priority for scheduling and curtailment under the same terms as other shippers. See COMPARABILITY OF SERVICE.
Gas-oil ratio. Generally, in the U.S., the volume of natural gas produced in cubic feet per barrel of oil produced.
A groove or scooped out cavity damage to pipe caused by a foreign object.
Governor, Zero Gas
A gas pressure regulating device common to industrial combustion systems used for controlling and reducing varying inlet gas pressures to atmospheric pressure at the device outlet.
GRADE (Gas Revenue Accounting Data Exchange)
An acronym for a system for the electronic communication of gas production and sales data between companies in the energy industry.
Grandfather Clause
The continuation of a former rule, clause, or policy (usually in a contractual agreement) where a change to a new rule or policy would be patently unfair to those covered by the former.
Gravity Survey
A method, using a gravity instrument, to detect variations in the gravitational pull of rocks in the subsurface. Variations or anomalies are contoured on a map and give evidence of geologic structures.
The layout of a gas distribution system in which pipes are laid in both directions in the streets and frequently connected at intersections. Also, a series of equally spaced parallel bars held together by equally spaced crosspieces; a screen.
Grille (Grill)
A covering over an air inlet or outlet with openings through which air passes.
Ground Temperature
An underground installation of anodes and coke breeze, etc. which is utilized for the control of corrosion of pipe and other metals; generally a rectifier is used in such installations.
Guideline Lives
Useful asset lives (by general categories) as determined and allowed for income tax depreciation charges by The Internal Revenue Service.
A resinous material formed in regulators, meters, and orifices from the polymerization of certain gas components present in manufactured gas, primarily heterocyclic and/or unsaturated hydrocarbons.
Gun Perforator
A device for making a hole through the casing, cement, and into the producing formation of a well to provide channels for flow of gas and/or oil into the well.


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