|  Definitions, Sources and Explanatory Notes |
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|  Category:   | Natural Gas Exploration & Reserves |
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|  Topic:      | Reserves Summary                   |
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|   Definitions |  |
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| Key Terms                               | Definition                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
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| Dry Natural Gas                         | Natural gas which remains after: 1) theliquefiable hydrocarbon portion has been removed from thegas stream (i.e., gas after lease, field, and/or plant separation);and 2) any volumes of nonhydrocarbon gases have beenremoved where they occur in sufficient quantity to render thegas unmarketable. (Note: Dry natural gas is also known asconsumer-grade natural gas. The parameters for measurementare cubic feet at 60 degrees Fahrenheit and 14.73 poundsper square inch absolute.)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Natural Gas Associated-Dissolved        | The combined volume of natural gas which occurs in crude oil reservoirs either as freegas (associated) or as gas in solution with crude oil (dissolved).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Natural Gas Liquids                     | Those hydrocarbons in natural gas which are separated from the gas through the processesof absorption, condensation, adsorption, or other methods in gas processing or cyclingplants. Generally such liquids consist of propane and heavier hydrocarbons and are commonly referred to as condensate, natural gasoline, or liquefied petroleum gases.Where hydrocarbon components lighter than propane are recovered as liquids, thesecomponents are included with natural gas liquids.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Natural Gas Nonassociated               | Natural gas not in contact with significant quantities of crude oil in a reservoir.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Natural Gas, Wet After Lease Separation | The volume of natural gas remaining after removal of lease condensate in lease and/orfield separation facilities, if any, and after exclusion of nonhydrocarbon gases wherethey occur in sufficient quantity to render the gas unmarketable.  Natural gas liquidsmay be recovered from volume of natural gas, wet after lease separation, at natural gasprocessing plants.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Proved Reserves of Natural Gas          | Proved reserves of natural gas as of December 31 of the report year are the estimatedquantities which analysis of geological and engineering data demonstrate with reasonablecertainty to be recoverable in future years from known reservoirs under existingeconomic and operating conditions.Reservoirs are considered proved if economic producibility is supported by actual productionor conclusive formation test (drill stem or wire line), or if economic producibility issupported by core analyses and/or electric or other log interpretations.The area of a gas reservoir considered proved includes: (1) that portion delineated bydrilling and defined by gas -- oil and/or gas -- water contacts, if any; and (2) theimmediately adjoining portions not yet drilled, but which can be reasonably judged aseconomically productive on the basis of available geological and engineering data. In theabsence of information on fluid contacts, the lowest known structural occurrence of hydrocarbons is considered to be the lower proved limit of the reservoir.Volumes of natural gas placed in underground storage are not to be considered proved reserves.For natural gas, wet after lease seperation, an appropriate reduction in the reservoir gasvolume has been made to cover the removal of the liquefiable portions of the gas in lease and/orfield separation facilities and the exclusion of nonhydrocarbon gases where they occur insufficient quantity to reder the gas unmarketable.For dry natural gas, an appropriate reduction in the gas volume has been made to cover theremoval of the liquefiable portions of the gas in lease and/or field separation facilities,and in natural gas processing plants, and the exclusion of nonhydrocarbon gases where theyoccur in sufficient quantity to render the gas unmarketable.It is not necessary that production, gathering, or transportation facilities be installed oroperative for a reservoir to be considered proved. It is to be assumed that compressionwill be initiated if and when economically justified. |
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| For definitions of related energy terms, refer to the   EIA Energy Glossary. |
|  	Sources |
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|  | Form EIA-23L, "Annual Report of Domestic Oil and Gas Reserves (County Level Version)".  Natural Gas Survey Forms and Instructions
 	Explanatory Notes
  Related data and background information are published in the      U.S. Crude Oil and Natural Gas Proved Reserves Annual Report. |