Table Definitions, Sources, and Explanatory Notes

Definitions, Sources and Explanatory Notes

Category:	Natural Gas Production

Topic:	Gross Withdrawals and Production


Definitions

Key Terms	Definition
Production	The volume of natural gas withdrawn from reservoirs less (1) the volume returned to such reservoirs in cycling, repressuring of oil reservoirs, and conservation operations; less (2) shrinkage resulting from the removal of lease condensate; and less (3) nonhydrocarbon gases where they occur in sufficient quantity to render the gas unmarketable. Volumes of gas withdrawn from gas storage reservoirs and native gas, which has been transferred to the storage category, are not considered production. Flared and vented gas is also considered production. (This differs from "Marketed Production" which excludes flared and vented gas.)
Gross Withdrawals	Full well-stream volume, including all natural gas plant liquids and all nonhydrocarbon gases, but excluding lease condensate. Also includes amounts delivered as royalty payments or consumed in field operations.
Gas Well	A well completed for the production of natural gas from one or more gas zones or reservoirs. Such wells contain no completions for the production of crude oil. As of report year 2021, well count data have been discontinued. The latest natural gas well count data can be found at U.S. Oil and Natural Gas Wells by Production Rate.
Oil Well (Casinghead) Gas	Natural gas produced along with crude oil from oil wells. It contains either dissolved or associated gas or both.
Repressuring	The injection of gas into oil or gas reservoir formations to effect greater ultimate recovery.
Nonhydrocarbon Gases	Typical nonhydrocarbon gases that may be present in reservoir natural gas, such as carbon dioxide, helium, hydrogen sulfide, and nitrogen.
Vented	Gas released into the air on the production site or at processing plants.
Flared	Gas disposed of by burning in flares usually at the production sites or at gas processing plants.
Marketed Production	Gross withdrawals less gas used for repressuring, quantities vented and flared, and nonhydrocarbon gases removed in treating or processing operations. Includes all quantities of gas used in field and processing plant operations.
Extraction Loss	The extraction of gas plant liquids constituents such as ethane, propane, normal butane, isobutane, plant condensate, and natural gasoline, sometimes referred to as extraction loss. Usually reported in barrels or gallons, but may be reported in cubic feet for purposes of comparison with dry natural gas volumes.
Dry Natural Gas Production	The process of producing consumer-grade natural gas. Natural gas withdrawn from reservoirs is reduced by volumes used at the production (lease) site and by processing losses. Volumes used at the production site include (1) the volume returned to reservoirs in cycling, repressuring of oil reservoirs, and conservation operations; and (2) gas vented and flared. Processing losses include (1) nonhydrocarbon gases (e.g., water vapor, carbon dioxide, helium, hydrogen sulfide, and nitrogen) removed from the gas stream; and (2) gas converted to liquid form, such as lease condensate and plant liquids. Volumes of dry gas withdrawn from gas storage reservoirs are not considered part of production. Dry natural gas production equals marketed production less extraction loss.

For definitions of related energy terms, refer to the EIA Energy Glossary.

Sources

1967-1975: Figures based on reports received from State agencies and Bureau of Mines estimates. 1976-1979: Appropriate State agencies' responses to informal data requests and the United state Geological Survey (USGS). 1980-1981: Form EIA-627, "Annual Quantity and Value of Natural Gas Report," and the USGS. 1982-1995: Form EIA-627, "Annual Quantity and Value of Natural Gas Report," and the United State Minerals Management Service; West Virginia, 1995 and 2000: EIA, U.S. Crude Oil, natural Gas, and Natural Gas Liquids Reserves, Annual Report, and EIA computations. 1996-present: Form EIA-895, "Monthly and Annual Quantity and Value of Natural Gas Production Report" , and the U.S. Mineral Management Service.

Explanatory Notes



	Beginning with 1965 data, all volumes are shown on a pressure base of 14.73 psia at 60 degres Fahrenheit. For prior years, the pressure base is 14.65 psia at 60 degrees Fahrenheit.
	From 1967 through 1970, Arizona, Florida, Missouri, and Tennessee are included in Alabama's volumes.
	From 1996 through 1999, nonhydrocarbon gases in New Mexico were removed from gross withdrawals in error and not corrected.
	Prior to 1997, state production for Texas, Louisiana, and Alabama includes a portion of the Federal Offshore Gulf of America production. Production for these states prior to 1997 excluding the Federal Offshore Gulf of America can be found at the state energy data system (seds).
	Federal Offshore Gulf of America production volumes are presented as a separate data series beginning in 2001. For Alabama, Louisiana and Texas all data through 2000 include Federal Offshore production Gulf of America.
	Form EIA-895A, for years prior to 2007, coalbed and shale production data are included in gas well totals. Coalbed and shale production volumes are broken out separately for 2007 forward using data from PointLogic Energy. Producing reservoirs may not be consistently classified in some areas; different interpretations of how to classify shale and non-shale formations are possible.
	For 2011 forward, state and Federal Offshore Gulf of America data were obtained directly from the states and BSEE. In instances where repressuring, vented and flared, nonhydrocarbon gases removed or fuel used on leases data were unavailable in 2011, EIA estimated these quantities by using the historic ratio of gross production to these items from previous years for each state; from 2012 forward, non-marketed components were reported as NA if not available directly from states.
	The monthly production series (sourced from the Natural Gas Monthly) are considered preliminary prior to the publication of the Natural Gas Annual (NGA). Upon NGA’s publication, the monthly production series are considered final. Final monthly data are the sums of monthly data collected on an annual schedule from state agencies (with predecessor Forms EIA-895A and EIA-627) and EIA-64A and EIA-816.
	For 2017 forward, monthly natural gas gross withdrawal volumes are available only for those states/areas that were collected individually on the EIA-914 survey (Arkansas, California, Colorado, Federal Offshore Gulf of America, Kansas, Louisiana, Montana, New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, Texas, Utah, West Virginia, and Wyoming). The “other states” category comprises states/areas not individually collected on the EIA-914 survey (Alabama, Arizona, Federal Offshore Pacific, Florida, Idaho, Illinois, Indiana, Kentucky, Maryland, Michigan, Mississippi, Missouri, Nebraska, Nevada, New York, Oregon, South Dakota, Tennessee, and Virginia). All data for Alaska are obtained directly from the state.
	For additional information on the production series, please reference the appendix section in the Natural Gas Annual or Natural Gas Monthly linked to the corresponding time period in question.

Nonhydrocarbon Gases Removed
	From 1980 through 1989, annual state repressuring, vented and flared, and non-hydrocarbon gases removed were collected on form EIA-627 from state agencies.
	Beginning with 1990, states agencies filing form EIA-627 were asked to supply monthly data of repressuring, vented and flared, and non-hydrocarbon gases removed that were previously reported on an annual basis.
	In 1996, Form EIA-627 was assigned a new number, EIA-895A. From 1996 through 2010, annual state repressuring, vented and flared, and non-hydrocarbon gases removed were collected on a monthly basis from state agencies and BOEMRE (and predecessor agencies) on Form EIA-895A.
	Form EIA-895A was discontinued in 2011. Starting in 2011, annual state repressuring, vented and flared, and non-hydrocarbon gases removed that included data collected on a monthly basis, were obtained directly from state agencies, state sponsored public record databases, or commercial data vendors. Annual collection of monthly production data for the Federal Offshore Gulf of America are provided by BSEE.

Marketed Production
	Marketed production is the sum of gross withdrawals less gas used for repressuring, quantities vented and flared, and nonhydrocarbon gases removed.
	From 2017 forward, state monthly marketed production is estimated from gross withdrawals using historical relationships between the two.

Natural Gas Processed and Extraction Loss
	Through 2018, The Form EIA-64A collects data on the volume of natural gas received for processing, the total quantity of natural gas liquids produced, and the resulting shrinkage (defined as extraction loss in this report) from all natural gas processing- and cycling-plant operators. The quantity of natural gas received and liquids produced are reported by state of origin of the natural gas. Shrinkage volumes are calculated and reported by plant operators based upon the chemical composition of the liquids extracted using standard conversion factors specified in the form instructions.
	To estimate the quantities of individual products extracted in each state, data from the Form EIA-64A survey were used to determine the total liquids production, and data from the Form EIA-816, "Monthly Natural Gas Liquids Report," survey were used to estimate the quantities of the individual products contained in those total liquids.
	The Form EIA-816 captures information on the quantity of individual components (i.e., ethane, propane, normal butane, isobutane, and pentanes plus) produced or contained in mixes of plant liquids as determined by chemical analysis. The volumetric ratios of the individual components to the total liquids, as calculated from the 12 monthly Form EIA-816 reports for each state, were applied to the annual total liquids production, as reported on the Form EIA-64A, to estimate the quantities of individual components removed at gas-processing plants.
	The heat (Btu) content of liquids extracted is not reported on the Form EIA-64A. Therefore, in order to estimate the extraction loss heat content, data reported on the Form EIA-816 were used to determine the individual products contained in the total liquids reported on Form EIA-64A.
	Beginning in 2019, the Form EIA-64A collects data by area of origin for inlet gas volumes and individual liquid components extracted (i.e., ethane, propane, normal butane, isobutene, natural gasoline, and plant condensate). Form EIA-64A also collects total residue gas, gas used for plant fuel, gas sent to a pipeline, and purchased electricity by gas plant. The individual liquid component volumes reported on Form EIA-64A by area of origin are used to calculate shrinkage (extraction loss) by state of origin and the heat content (Btu) of the extracted liquids
	The shrinkage (extraction loss) was estimated by applying conversion factors to the volumes of the individual products extracted in each state. These conversion factors, in Mcf/bbl, are ethane, 1.558; propane, 1.498; normal butane, 1.289; isobutane, 1.247; natural gasoline,1.050; and plant condensate, 0.811.
	The heat (Btu) content of extracted liquids was estimated by applying conversion factors to the estimated quantities of products extracted in each state. These conversion factors, in million Btu per barrel of liquid produced, were ethane, 3.082; propane, 3.836; normal butane, 4.326; isobutane,3.974; and pentane plus, 4.620. It should be noted that, at the state level, extraction losses are not necessarily related to state production.
	Through 2011, extraction loss volumes for the Federal Offshore Gulf of America are included in the total extraction loss volumes for the States of Alabama, Louisiana, and Texas.
	Monthly data are revised after the publication of the Natural Gas Annual. Final monthly data are estimated by allocating annual extraction loss data to each month based on its total natural gas marketed production.