Natural Gas

The price effects of the economic slowdown following the COVID-19 pandemic contributed to reductions in U.S. petroleum and natural gas reserves in 2020. Proved reserves of crude oil and lease condensate decreased by 9 billion barrels in 2020, a decline of 19%, and proved reserves of natural gas decreased by just over 22 trillion cubic feet (Tcf), a decline of 4% (Table 1).

The COVID-19 pandemic had significant effects on the reserves we report in this paper. On March 11, 2020, the World Health Organization characterized the COVID-19 outbreak as a pandemic, and on March 13, 2020, President Trump declared a national emergency in the United States. Many states imposed mandatory lockdowns and issued stay-at-home orders, and in addition to travel restrictions, people also voluntarily chose not to travel to avoid exposure. Consequently, demand fell for transportation fuels, and fuel prices fell. Liquid fuel production also faced a critical shortage of available storage. Operators revised their proved reserves downward in 2020 and postponed developmental drilling.

Oil highlights

• Proved reserves of U.S. crude oil and lease condensate declined 19%, from 47.2 billion barrels to 38.2 billion barrels at the end of 2020. Proved reserves of crude oil decreased 8.4 billion barrels in 2020, and proved reserves of lease condensate (produced from natural gas wells) decreased by 560 million barrels (Table 5).
• U.S. production of crude oil and lease condensate decreased by 7% in 2020 (Table 5).
• Texas, the state with the largest volume of proved reserves of crude oil and lease condensate, had the largest net decrease in proved reserves in 2020 (3.1 billion barrels or 16%) (Table 6).
• North Dakota had the second-largest net decrease (2.2 billion barrels or 38%), and the Federal Offshore Gulf of Mexico experienced the third-largest decline (0.8 billion barrels or 16%).
• The largest net increase in proved reserves of crude oil and lease condensate in 2020 was in Utah (91 million barrels or 30%) (Table 6).
• The annual average spot price for West Texas Intermediate (WTI) crude oil at Cushing, Oklahoma, decreased by 28% from $55.17 per barrel in 2019 to $39.66 per barrel in 2020 (Figure 6).

Natural gas highlights

• Proved reserves of natural gas decreased 4%, from 495.4 Tcf at year-end 2019 to 473.3 Tcf at year-end 2020 (Table 10).
• This decrease was the second consecutive annual decrease in proved reserves of natural gas in the United States.
• Producers in Alaska added a substantial new volume of proved natural gas reserves in 2020. The annual total of proved natural gas reserves in Alaska increased in 2020 by 27 Tcf, quadrupling the state’s total from 9 Tcf to 36 Tcf.
• Producers in Texas reported the largest decrease in proved reserves of natural gas in 2020 (11 Tcf or 9%). Pennsylvania saw the second-largest decrease of natural gas proved reserves (9.6 Tcf or 9%).
• The annual average spot price for natural gas at the Louisiana Henry Hub decreased by 24% from $2.63 per million British thermal units (MMBtu) in 2019 to $1.99 per MMBtu in 2020 (Figure 7).

Proved reserves are estimated volumes of hydrocarbon resources that analysis of geologic and engineering data demonstrates with reasonable certainty ¹ are recoverable under existing economic and operating conditions. Reserves estimates change from year to year because of:

• New discoveries
• Thorough appraisals of existing fields
• Production of existing reserves
• Changes in prices, costs, ownership, or planned infrastructure
• New and improved techniques and technologies

To prepare this report, we collected independently developed estimates of proved reserves from a sample of operators of U.S. oil and natural gas fields with Form EIA-23L. We use this sample to further estimate the portion of proved reserves from operators who do not report. We received responses from 371 of 404 sampled operators, which provided coverage of about 90% of proved reserves of oil and natural gas at the national level. We developed estimates for the United States, each state individually, and some state subdivisions. States and regions with subdivisions include:

• California
• Louisiana
• New Mexico
• Texas
• Federal Offshore Gulf of Mexico

National summary

Table 1. U.S. proved reserves, and reserves changes, 2019–20

	Crude oil billion barrels	Crude oil and lease condensate billion barrels	Total natural gas trillion cubic feet
U.S. proved reserves as of December 31, 2019	44.2	47.2	495.4
Extensions and discoveries	3	3.2	39.8
Net revisions	-8.8	-9.6	-98.2
Net adjustments, sales, acquisitions	1.2	1.6	73.4
Estimated production	-3.8	-4.2	-37.1
Net additions to U.S. proved reserves	-8.4	-9	-22.1
U.S. proved reserves as of December 31, 2020	35.8	38.2	473.3
Percent change in U.S. proved reserves	-19.00%	-19.00%	-4.50%
Source: U.S. Energy Information Administration, Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves Notes: Total natural gas includes natural gas plant liquids. Columns may not add to total because of independent rounding.

Between 1980 and 1996, U.S. reserves of natural gas and crude oil experienced a steady decline (Figure 1). In 1997, the downward trend for natural gas reserves reversed as operators introduced innovations in directional drilling and hydraulic fracturing techniques that successfully increased proved reserves and production of natural gas from shale formations. In 2008, the downward trend for crude oil reversed when operators applied innovations in directional drilling and hydraulic fracturing to tight oil-bearing formations, such as the Bakken shale of the Williston Basin. The upward reserves and production trends continued until 2015, when the industry experienced a significant drop in prices of both oil and natural gas, and proved reserves were revised downward because the lower prices did not support operators’ projections of resource development. From 2016 to 2018, U.S. oil and natural gas prices and reserves both trended upward by at least 9% each year. In 2019, that trend of rising reserves was interrupted, and in 2020, proved reserves declined for both fuels, similar to the drop observed five years before in 2015.

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Proved U.S. reserves of crude oil and lease condensate combined decreased in each of the seven states with the most oil reserves in 2020 (Figure 2). In 2020, operators in Texas reported the largest net decrease in its proved reserves of crude oil and lease condensate—a decrease of 3,108 million barrels.

Operators in North Dakota decreased their proved crude oil and lease condensate reserves by the next largest amount in 2020—a net decrease of 2,227 million barrels. The third-largest net decrease in proved reserves of crude oil and lease condensate in 2020 occurred in the Federal Offshore Gulf of Mexico, a net decrease of 818 million barrels.

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Proved natural gas reserves decreased in five of the eight states with the most reserves in 2020 (Figure 3), but one state actually added a substantial new volume of proved reserves. In Alaska, a large-scale liquefied natural gas development project received federal approval in May 2020.² This project included a new pipeline to bring natural gas from the north slope of Alaska to liquefaction and export facilities on the southern coast. With the pipeline, a large volume of previously stranded natural gas resources began to meet the definition of proved reserves. Proved natural gas reserves increased in Alaska in 2020 by 27 trillion cubic feet (Tcf), quadrupling the state’s total from 9 Tcf to 36 Tcf.

Operators in Texas reported the largest net decrease in proved natural gas reserves of any state, down 11.4 Tcf. Operators in Pennsylvania reported the second-largest net decrease in proved natural gas reserves in 2020, down by 9.6 Tcf. These decreases resulted from net downward revisions to proved reserves of natural gas due to low prices. The average U.S. natural gas price³ declined 24% in 2020, curtailing development plans and reducing the economically recoverable volume of existing proved reserves.

Operators in New Mexico added the second-most proved reserves of natural gas in 2020, an increase of 1.8 Tcf, largely from development in the Bone Spring/Wolfcamp shale play in the Delaware Basin in the eastern subdivision of the state. Operators in Louisiana increased their proved natural gas reserves by the third-largest amount—a net addition of 0.8 Tcf, where extensions in the Haynesville shale play exceeded net downward revisions of proved natural gas reserves.

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In 2020, annual production of crude oil and lease condensate decreased in the United States by 7% (336 million barrels). Crude oil imports decreased 13% (332 million barrels) from 2019 (Figure 4).

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U.S. natural gas production decreased by 1% (350 billion cubic feet [Bcf]) in 2020, and natural gas imports decreased by 7% (191 Bcf) from the 2019 level (Figure 5).

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Background

This report provides estimates of U.S. proved reserves of crude oil and lease condensate and proved reserves of natural gas as of the end of 2020. We measure changes for 2020 as the difference between year-end 2019 and year-end 2020 estimates. We process data filed on Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves, submitted by 371 of the 404 sampled operators of U.S. oil and natural gas fields. We then estimated the portion of proved reserves that is not reported for the United States, each state, and some federal offshore and state subdivisions. State subdivisions (for example, California Coastal Region Onshore, Louisiana North, Texas Railroad Commission District 1) are defined geographic areas within a large producing state or offshore area. State subdivision boundaries typically align with the boundaries of internal state conservation commission districts that collect production data. Within this report, we provide proved reserves for state subdivisions of California, Louisiana, New Mexico, Texas, and the Federal Offshore Gulf of Mexico.

Proved reserves are estimated volumes of hydrocarbon resources that analysis of geologic and engineering data demonstrates with reasonable certainty are recoverable under existing economic and operating conditions. Reserves estimates change from year to year because of:

• New discoveries
• Thorough appraisals of existing fields
• Production of existing reserves
• Changes in prices, costs, ownership, or planned infrastructure
• New and improved techniques and technologies

Discoveries include new fields, new reservoirs in previously discovered fields, and additional reserves that resulted from drilling and exploration in previously discovered reservoirs (extensions). Extensions typically make up the largest share of total discoveries. Beginning with the 2016 report, operators reported to us on Form EIA-23L their discoveries as a single, combined category—extensions and discoveries. Totals for that category are presented in one column on the data tables in this report.

Revisions primarily occur when operators change their estimates of what they will be able to produce from the properties they operate in response to changing prices, costs, or improvements in technology. Higher fuel prices typically increase estimates (positive revisions) as operators consider a broader portion of the resource base economically producible with reasonable certainty, or proved. Lower prices, on the other hand, generally reduce estimates (negative revisions) as operators estimate that less of their resource base is economically producible.

The U.S. Securities and Exchange Commission (SEC) revised its procedure for determining the prices underpinning its proved reserves estimates in 2008 to make reserves estimates less sensitive to price fluctuations. The 2008 SEC rules require companies to use an average of the 12 first-day-of-the-month prices. We require companies to follow the same procedure. SEC and EIA estimates are not exactly the same, however; SEC requires companies to report their owned reserves, and EIA requires companies to report their operated reserves.

Spot market prices are not necessarily the prices used by operators in their reserve estimates because actual prices received by operators depend on their particular contractual arrangements, location, and hydrocarbon quality, among other factors. However, spot prices do provide a benchmark or trend indicator.

The 12-month, first-day-of-the-month average spot price for West Texas Intermediate (WTI) crude oil (the U.S. benchmark location for crude oil) in 2020 was $39.66 per barrel—a price drop of 28% from 2019 (Figure 6).

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The 12-month, first-day-of-the-month average natural gas spot price at Louisiana’s Henry Hub (the U.S. benchmark location for natural gas) for 2020 was $1.99 per million British thermal units (MMBtu)—a 24% decrease from the previous year’s average spot price of $2.63/MMBtu (Figure 7).

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Proved reserves outlook for EIA’s next report (2021).
From December 2020 through February 2021, three separate COVID-19 vaccines (Pfizer-BioNTech, Moderna, and Janssen) received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA). Approval and distribution of effective vaccines contributed to the end of mandatory lockdowns in the United States and increased demand for transportation fuels.

During 2021, the 12-month, first-of-the-month average crude oil spot price for West Texas Intermediate at Cushing, Oklahoma and the natural gas spot price at the Henry Hub in Louisiana both increased from the 2020 level. The oil price rose 67% (from $39.66 per barrel to $66.26 per barrel), and the natural gas price rose 84% (from $1.99/MMBtu to $3.67/MMBtu). On December 31, 2021, the WTI daily spot price was $75.99 per barrel, and the natural gas daily spot price at the Henry Hub was $3.82/MMBtu.

In January 2021, only 374 rotary rigs were operating in the United States.⁴ As of December 31, 2021, in response to rising prices, the number of rigs operating in the United States rose to 586 rigs.⁵ As a result, we expect operators to report increased additions of proved reserves from extensions and discoveries in 2021.

According to our Short-Term Energy Outlook (STEO) forecast, U.S. production in 2022 will increase an estimated 7% for crude oil and 4% for natural gas. When combined with higher prices, increased rig counts, and more annual production, we anticipate that total U.S. proved reserves will rebound in 2021 for both crude oil and natural gas.

Proved reserves of crude oil and lease condensate

We estimate that the United States had 38,212 million barrels of proved reserves of crude oil and lease condensate as of December 31, 2020—a decrease of 19% from year-end 2019. Proved reserves declined 9% in Alaska, declined 20% onshore in the Lower 48 states (excluding Federal Offshore [both Pacific and the Gulf of Mexico]), and declined 16% in the Federal Offshore (both Pacific and the Gulf of Mexico)(Figure 8).

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U.S. proved reserves of crude oil and lease condensate decreased by almost 9 billion barrels (19%) in 2020, as the downward net revisions and production each exceeded the 3.24 billion barrels of total discoveries for the year (Figure 9a).

Operators in Texas reported the largest net decrease in proved crude oil and lease condensate reserves (3,108 million barrels) of all states in 2019—a decrease of 16% from 2019.

Operators in North Dakota had the second-largest net decrease in 2020 (2,227 million barrels) of proved crude oil and lease condensate reserves—a decrease of 38% from 2019.

Operators in the Federal Offshore Gulf of Mexico reported the third-largest net decrease in proved crude oil and lease condensate reserves (818 million barrels) in 2020—a decrease of 16% from 2019.

Utah experienced the largest net increase in proved crude oil reserves of all states in 2020 at 91 million barrels (31%). Extensions and discoveries of 92 million barrels of new proved crude oil reserves were reported in 2020, mostly from operators drilling horizontal wells in the Uinta Basin.

Figure 9b summarizes the components of changes in U.S. crude oil and lease condensate reserves over time:

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Extensions and discoveries
Exploration—including discovering new fields, identifying new reservoirs in fields discovered in previous years, and adding reserves that result from additional drilling in previously discovered reservoirs (extensions)—added 3.2 billion barrels to U.S. crude oil and lease condensate reserves in 2020. Extensions and discoveries in 2020—which are typically the largest component of proved reserves change in a given year—were the least observed in the past three years (Figure 9b). Both production and net negative revisions to proved reserves in 2020 outweighed any gains.

The largest extensions and discoveries of proved reserves of crude oil and lease condensate in 2020 were in Texas, New Mexico, and North Dakota. Operators in Texas had 1.8 billion barrels, in New Mexico had 0.7 billion barrels, and in North Dakota had 0.2 billion barrels of extensions and discoveries in 2020; however, operators in all three of these states reported net declines in their proved reserves of crude oil and lease condensate in 2020.

Net revisions and other changes
Revisions to reserves occur primarily when operators change their estimates of what they are able to economically produce using existing technology and current economic conditions. Current prices are critical in estimating economically producible reserves. Other changes occur when operators buy and sell properties (revaluing the proved reserves in the process) and when various adjustments are made to reconcile estimated volumes.

Net downward revisions decreased proved reserves of U.S. crude oil and lease condensate by 9.6 billion barrels in 2020. The largest net downward revisions of proved reserves of crude oil and lease condensate occurred in Texas (the state with the most proved reserves of crude oil and lease condensate which was impacted the most by lower prices in 2020.) Net revisions of proved reserves of crude oil and lease condensate accounted for a decrease of 3.8 billion barrels in 2020 in Texas.

The proved reserves of U.S. crude oil and lease condensate associated with buying and selling properties⁶ resulted in a net increase of 334 million barrels in 2020.

Adjustments
Adjustments are the yearly changes in the published reserve estimates that cannot be attributed to the estimates for other reserve change categories because of the survey and statistical estimation methods employed. For example, if last year’s year-end reserves for a state or state subdivision don’t match this year’s beginning year reserves, we must make an adjustment to account for that difference. Other examples that contribute to adjustments include changes in the selected reporting companies from the previous year and imputations for missing or unreported reserve changes.

In 2020, the sum of all of our adjustments for U.S. proved oil reserves was 1,244 million barrels.

Production
Our official published estimate of total U.S. crude oil production (including lease condensate) is 4,130 million barrels for 2020, a decrease of 8% from 2019. As estimated using Form EIA-23L responses, the United States produced 4,154 million barrels of crude oil and lease condensate in 2020, a decrease of 7% from 2019 (Tables 5 and 6).⁷

Production of crude oil and lease condensate onshore in the Lower 48 states (3,371 million barrels) was 6% lower than in 2019 (3,608 million barrels), and Federal Offshore (both Pacific and Gulf of Mexico) production experienced a 13% decrease based on the Form EIA-23L data (declining from 711 million barrels in 2019 to 621 million barrels in 2020).

Crude oil and lease condensate from U.S. shale plays

As of December 31, 2020, seven major shale plays accounted for 51% of all proved reserves of U.S. crude oil and lease condensate (Table 2). The Wolfcamp/Bone Spring shale play in the Permian Basin remains the largest oil-producing shale play in the United States. We publish a series of maps showing major U.S. shale plays.

Table 2. Crude oil production and proved reserves from selected U.S. tight plays, 2019–20
million barrels

Basin	Play	State(s)	2019 production	2019 proved reserves	2020 production	2020 proved reserves	2019–20 reserves change
Permian	Wolfcamp/Bone Spring	NM, TX	1,209	12,069	1,322	11,870	-199
Williston	Bakken/Three Forks	ND, MT, SD	517	5,845	431	3,685	-2,160
Western Gulf	Eagle Ford	TX	451	4,297	399	3,246	-1,051
Anadarko, South Oklahoma	Woodford	OK	53	524	46	378	-146
Appalachian	Marcellus*	PA, WV	21	326	23	247	-79
Denver-Julesburg	Niobrara	CO, KS,NE, WY	25	235	16	218	-17
Fort Worth	Barnett	TX	2	19	1	15	-4
Sub-total			2,278	23,240	2,238	19,659	-3,581
Source: U.S. Energy Information Administration, Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves, 2019 and 2020 Notes: Includes lease condensate. Bakken/Three Forks oil includes proved reserves from shale or low-permeability formations reported on Form EIA-23L. Wolfcamp/Bone Spring includes proved reserves from shale or low-permeability formations reported on Form EIA-23L in TX RRC 7C, TX RRC 8, TX RRC 8A, and NME. * The Marcellus play in this table refers only to portions within Pennsylvania and West Virginia.

Proved reserves of natural gas

Operators in the United States reported 473.3 Tcf of proved natural gas reserves as of December 31, 2020. Total U.S. proved reserves of natural gas (including natural gas plant liquids [NGPLs]) decreased by 4% (22.1 Tcf) from 2019 (Figure 10).

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The average natural gas price⁸ declined 24% in 2020 compared with 2019, causing many operators to revise their proved reserves downward. Extensions and discoveries of natural gas proved reserves in 2020 were slightly (2.7 Tcf) more than the annual production of 37.1 Tcf (Figure 11a), and net downward revisions (98.2 Tcf) drove down the 2020 national total as a result.

Operators in Texas and Pennsylvania, the states with the first- and second-most natural gas proved reserves in the United States, reported a 9% decline in their proved reserves of natural gas in 2020. Proved reserves of natural gas decreased by 11.4 Tcf in Texas and decreased by 9.6 Tcf in Pennsylvania.

Proved natural gas reserves nationwide were on course to decline more than 10%, but on May 21, 2020, the U.S. Federal Regulatory Commission (FERC) announced approval of the Alaskan LNG Project, a large-scale liquefied natural gas development project.⁹ Described in FERC Docket No. CP17-178-000, “The Alaska LNG Project consists of: a gas treatment plant located in the Prudhoe Bay Unit of Alaska’s North Slope, and two natural gas pipelines connecting production units to the gas treatment plant; an approximately 806.9-mile-long, 42-inch-diameter pipeline (Mainline Pipeline) capable of transporting up to 3.9 billion cubic feet per day (Bcf/d) from the gas treatment plant to the liquefaction facilities; 344,000 horsepower of compression located at eight compressor stations along the Mainline Pipeline; and liquefaction facilities on the Kenai Peninsula designed to produce up to 20 million metric tons per year of LNG for export.”

Approval of this project means that a large volume of previously stranded Alaskan natural gas resources now meets the definition of proved reserves. The annual total of natural gas proved reserves in Alaska increased in 2020 by 27 Tcf, quadrupling the state’s total from 9 Tcf to 36 Tcf. Additional upstream production facilities will add more proved reserves in years to come.

Extensions and discoveries
Extensions and discoveries in 2020 added 39.8 Tcf to proved U.S. natural gas reserves (Table 3). Operators in Pennsylvania reported the largest extensions and discoveries of proved natural gas reserves in the United States in 2020, totaling 12.4 Tcf (Table 10). These extensions were part of the continuing development of the Marcellus shale natural gas play of Pennsylvania and West Virginia.

Operators in Texas reported the next-largest volume of extensions and discoveries in 2020 (8.1 Tcf). The largest portion of these extensions and discoveries were from TX RRC Commission District 8 in the Delaware Basin (Wolfcamp shale play).

Table 3. Changes to proved reserves of U.S. natural gas by source, 2019–20
trillion cubic feet

Source of natural gas	Year-end 2019 proved reserves	2020 extensions and discoveries	2020 revisions and other changes	2020 estimated production	Year-end 2020 proved reserves
Shale	353.7	32.7	-42.5	-26.1	317.8
Other U.S. natural gas
Lower 48 states onshore	125.9	7	-9.2	-9.8	113.9
Lower 48 states offshore	6.4	0	-0.4	-0.9	5.1
Alaska	9.4	0.1	27.3	-0.2	36.5
U.S. total	495.4	39.8	-24.9	-37.1	473.3
Source: U.S. Energy Information Administration, Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves, 2019 and 2020 Note: The Lower 48 states offshore subtotal in this table includes state offshore and Federal Offshore. Components may not add to total because of independent rounding.

Net revisions and other changes
The most significant change of 2020 in proved natural gas reserves was in Alaska, where approval of the Alaska LNG Project resulted in increased proved reserves (Table 3). In the Lower 48 states, the following states had the next largest changes due to net revisions of 2020, all of which were negative:

• Operators in Texas decreased their proved natural gas reserves more than in any of the Lower 48 states in 2020 due to net revisions (14.1 Tcf)
• Operators in Pennsylvania reported the second-largest net revision decreases (12.0 Tcf)
• Operators in Oklahoma had the third-largest net revision decrease (8.7 Tcf)

Adjustments
Adjustments are yearly changes in the published reserve estimates that we cannot attribute to other reserve change categories. In 2020, the sum of all of our adjustments for U.S. proved natural gas reserves was 5.2 Tcf.

Production
Our official published estimate of marketed natural gas production was 36.2 Tcf in 2020, a decrease of less than 1% from 2019 (36.4 Tcf). Using Form EIA-23L responses instead of official statistics, we estimate that U.S. production of total natural gas, wet after lease separation, in 2020 was 37.1 Tcf—also a decrease of 1% from the 2019 estimate (37.4 Tcf) published in last year’s report (Tables 9 and 10).¹⁰

Figure 11b illustrates the components of U.S. natural gas annual reserves changes over time.

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Nonassociated natural gas
Nonassociated natural gas, also called gas well gas, is defined as natural gas not in contact with significant quantities of crude oil in a reservoir. Nonassociated natural gas accounted for 71% of proved natural gas reserves in the United States in 2020. The U.S. total of proved reserves of nonassociated natural gas decreased from 373.1 Tcf in 2019 to 336.9 Tcf in 2020—a decrease of 10% (Table 11). Using Form EIA-23L responses, estimated production of U.S. nonassociated natural gas decreased 2%—from 27.3 Tcf in 2019 to 26.7 Tcf in 2019. The largest decrease in 2020 proved nonassociated natural gas reserves (9.6 Tcf) was in Pennsylvania. The largest increase in 2020 proved nonassociated natural gas reserves (1.6 Tcf) was in Louisiana.

Associated-dissolved natural gas
Associated-dissolved natural gas, also called casinghead gas, is defined as the combined volume of natural gas that occurs in crude oil reservoirs either as free gas (associated) or as natural gas in solution with crude oil (dissolved). Associated-dissolved natural gas accounted for 29% of proved natural gas reserves in the United States in 2020. The U.S. total proved reserves of associated-dissolved natural gas increased from 122.2 Tcf in 2019 to 136.4 Tcf in 2020—an increase of 11.6% (Table 12). Using Form EIA-23L responses, estimated production of associated-dissolved natural gas increased 2%—from 10.2 Tcf in 2019 to 10.4 Tcf in 2020. The largest increase of proved reserves of associated-dissolved natural gas in 2020 occurred in Alaska (27.4 Tcf). The largest decrease of associated dissolved natural gas in 2020 occurred in North Dakota (4.5 Tcf).

Coalbed natural gas (discontinued since the 2018 report)
At year-end 2017, proved reserves of coalbed methane represented 2.6% of total U.S. proved natural gas reserves.¹¹ We have not published proved coalbed methane reserves as a separate data category since the 2017 report. They are now included as conventional natural gas.

Natural gas from U.S. shale plays
Shale formations can be both the source rock (where the oil and natural gas are generated from organic matter in the rock) and the producing formation (the rock from which the oil and natural gas are produced). When a sandstone or carbonate formation produces oil and natural gas, these rock layers are typically permeable enough to allow oil and natural gas to easily flow to a nearby wellbore. Shale formations have very low permeability and must typically be hydraulically fractured to produce natural gas at economical rates. Horizontally-drilled wells perform substantially better than vertical wells, although they are more expensive to drill and complete at the same depth because they are longer and the drilling process is more complex.¹² Proved reserves of U.S. natural gas from shale decreased 10%, from 353.7 Tcf in 2019 to 317.8 Tcf in 2020 (Table 13).

The share of total U.S. natural gas reserves made up by natural gas reserves from shale decreased from 71% in 2019 to 67% in 2020 (Figure 12). Estimated production of natural gas from shale increased 2%—from 25.6 Tcf in 2019 to 26.1 Tcf in 2020 (Table 13).

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The eight states that reported the most proved reserves of shale natural gas in 2020 are shown in Figure 13. Operators in Pennsylvania reported the most proved reserves of shale natural gas in 2020 with 96.7 Tcf. Operators in Texas reported the second-largest reserves with 87.3 Tcf. Proved shale natural gas reserves located in West Virginia totalled 32.3 Tcf, making it the state with the third-most proved shale natural gas reserves in 2020. Of these eight states, only operators in New Mexico reported an increase (albeit slight) in statewide proved reserves of shale natural gas in 2020. Downward revisions were countered by extensions and discoveries in eastern New Mexico’s Delaware Basin.

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We collected production and proved reserves data for nine major U.S. shale plays in 2020 (Table 4). The Marcellus shale play remained the play with the largest amount of proved reserves of natural gas from shale in 2020. Proved reserves in the Marcellus shale play decreased by 10.4 Tcf (7%) in 2020. The second-largest shale play in 2020 was the Wolfcamp/Bone Spring shale play of the Permian Basin. Proved shale natural gas reserves in the Wolfcamp/Bone Spring shale play increased by 2.6 Tcf (5%) in 2020.

Table 4. U.S. shale plays: production and proved reserves of natural gas, 2019–20
trillion cubic feet

Basin	Shale play	State(s)	2019 Production	2019 Proved Reserves	2020 Production	2020 Proved Reserves	Change in Production	Change in Proved Reserves
Appalachian	Marcellus*	PA, WV	8.7	139.4	9.3	129	0.6	-10.4
Permian Basin	Wolfcamp/Bone Spring	NM,TX	4.5	49.9	5.2	52.5	0.7	2.6
TX-LA Salt	Haynesville/Bossier	LA, TX	3.4	46.7	3.6	44.8	0.2	-1.9
Western Gulf	Eagle Ford	TX	2.1	26.6	1.9	22.3	-0.2	-4.3
Appalachian	Utica/Pt. Pleasant	OH	2.6	34.4	2.3	27.8	-0.3	-6.6
Anadarko, S. OK	Woodford	OK	1.5	20.9	1.2	15.5	-0.3	-5.4
Fort Worth	Barnett	TX	1.1	14.1	1	10.8	-0.1	-3.3
Williston	Bakken/Three Forks	MT, ND	1	12.2	1	8.6	0	-3.6
Arkoma	Fayetteville	AR	0.5	5.1	0.4	4.2	-0.1	-0.9
Sub-total			25.4	349.3	25.9	315.5	0.5	-33.8
Other shale gas			0.1	3.8	0.2	2.2	0.1	-1.6
All U.S. shale gas			25.5	353.1	26.1	317.7	0.6	-35.4
Sources: U.S. Energy Information Administration, Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves, 2019 and 2020 Note: Table values are based on natural gas proved reserves and production volumes from shale reported and imputed from data on Form EIA-23L. * In this table, the Marcellus shale play refers only to portions within Pennsylvania and West Virginia. Other shale includes proved reserves and production reported from shale on Form EIA-23L that we assign to the Niobrara, Antrim, and Monterey shale plays. Columns may not add to subtotals because of independent rounding.

EIA publishes a series of maps showing the nation’s shale natural gas resources for both shale plays and geologic basins.

Proved U.S. reserves of dry natural gas
Dry natural gas is the volume of natural gas that remains after natural gas liquids and non-hydrocarbon impurities are removed from the natural gas stream, usually downstream at a natural gas processing plant. Not all produced natural gas has to be processed at a natural gas processing plant. Some produced natural gas is sufficiently dry and satisfies pipeline transportation standards without processing.

We calculate our estimate of the proved reserves of dry natural gas in the United States by first estimating the expected yield of NGPLs from total natural gas proved reserves and by then subtracting the natural gas equivalent volume of the NGPLs from total natural gas proved reserves.

Proved reserves of dry natural gas in the United States decreased by 4% from an estimated 465.4 Tcf in 2019 to 445.3 Tcf in 2020.¹³

Proved reserves of lease condensate and natural gas plant liquids

Operators of natural gas fields report their estimates of lease condensate reserves and production to us on Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves. We determine data for NGPLs from data reported on Form EIA-64A, Annual Report of the Origin of Natural Gas Liquids Production. We calculate the expected yield of NGPLs by using estimates of total natural gas reserves and a recovery factor determined for each area of origin based on Form EIA-64A data.

Lease condensate
Lease condensate is a mixture consisting primarily of hydrocarbons heavier than pentanes that is recovered as a liquid from natural gas in lease separation facilities. This category excludes NGPLs, such as propane, butane, and natural gasoline, which are recovered at downstream natural gas processing plants. Lease condensate usually enters the crude oil stream.

As of December 31, 2020, the United States had proved reserves of 2,377 million barrels of lease condensate, a decrease of 560 million barrels from 2019 (19%) (Table 8). U.S. lease condensate production decreased 4%—from 321 million barrels in 2019 to 308 million barrels in 2020.

NGPLs
Natural gas plant liquids (NGPLs) (unlike lease condensate) remain within the natural gas after it passes through lease separation equipment. These liquids are normally separated from the natural gas at processing plants, fractionators, and cycling plants. NGPLs that are extracted include ethane, propane, butane, isobutane, natural gasoline, and plant condensate. Plant condensate is similar to lease condensate in that it usually enters the crude oil stream, but is recovered at a natural gas processing plant rather than lease separation facilities.

The estimated volume of natural gas plant liquids contained in proved reserves of total natural gas decreased from 21.8 billion barrels in 2018 to 21.7 billion barrels in 2019 (a 0.9% decrease)(Table 15).¹⁴

Reserves in nonproducing reservoirs

Not all proved reserves are contained in actively producing reservoirs. Reserves within actively producing reservoirs are known as proved, developed, producing reserves. Two additional categories for proved reserves exist: proved, developed, nonproducing reserves (PDNPs), and proved, undeveloped reserves (PUDs).

Examples of PDNPs include existing producing wells that are shut in awaiting well workovers, drilled wells that await completion, drilled well sites that require installation of production equipment or pipeline facilities, and behind-the-pipe reserves that require the depletion of other zones or reservoirs before they can be placed on production (by recompleting the well).

An example of PUDs are undrilled offset well locations (acreage adjacent to an existing producing well that is scheduled to have wells drilled on it). However, additional conditions must be met to satisfy the definition of proved reserves. These locations must:

• be directly offset to wells that have production in the objective formation
• be reasonably certain to be within the known proved productive limits of the objective formation
• conform to existing well spacing regulations where applicable, and
• be reasonably certain to be developed within a five-year period

Reserves from other locations beyond direct offset wells are categorized as proved, undeveloped reserves only where interpretations of geological and engineering data from wells indicate with reasonable certainty that the objective formation is laterally continuous and contains commercially recoverable petroleum at that location.

As of December 31, 2020, the United States had 10.6 billion barrels of crude oil proved reserves and 140.2 Tcf of natural gas proved reserves in nonproducing reservoirs (Table 16). These volumes are a 35% decrease for crude oil and a 24% decrease for total natural gas in nonproducing reservoirs from the 2019 levels published in our previous report. ¹⁵

Maps and additional data tables

Maps
Figure 14. Proved reserves of U.S. crude oil and lease condensate by state/area, 2020
Figure 15. Changes in proved reserves of crude oil and lease condensate by state/area, 2019–20
Figure 16. Proved reserves of U.S. natural gas by state/area, 2020
Figure 17. Changes in proved reserves of natural gas by state/area, 2019–20

Oil tables
Table 5. U.S. proved reserves of crude oil and lease condensate, crude oil, and lease condensate, 2010–20
Table 6. Proved reserves, reserves changes, and production of crude oil and lease condensate, 2020
Table 7. Proved reserves, reserves changes, and production of crude oil, 2020
Table 8. Proved reserves, reserves changes, and production of lease condensate, 2020

Natural gas tables
Table 9. U.S. proved reserves of total natural gas, wet after lease separation, 2001–20
Table 10. Proved reserves, reserves changes, and production of natural gas, wet after lease separation, 2020
Table 11. Proved reserves, reserves changes, and production of nonassociated natural gas, wet after lease separation, 2020
Table 12. Proved reserves, reserves changes, and production of associated-dissolved natural gas, wet after lease separation, 2020
Table 13. Proved reserves and production of shale natural gas, 2017–20
Table 14. Proved reserves, reserves changes, and production of shale natural gas, 2020
Table 15. Estimated proved reserves of natural gas plant liquids and dry natural gas, 2020

Miscellaneous/other tables
Table 16. Reported proved nonproducing reserves of crude oil, lease condensate, nonassociated gas, associated-dissolved gas, and total gas, wet after lease separation, 2020

 

Footnotes:

1.Reasonable certainty assumes a probability of recovery of 90% or greater.

2. ORDER GRANTING AUTHORIZATION UNDER SECTION 3 OF THE NATURAL GAS ACT, http://alaska-lng.com/wp-content/uploads/2020/05/20200521-3111-34088269-FERC-Order.pdf

3. The 12-month, 1^st-of-the-month, average spot price of natural gas at the Louisiana Henry hub.

4.U.S. Energy Information Administration, Crude Oil and Natural Gas Drilling Activity, Graph by U.S. Energy Information Administration, based on data from Baker Hughes, Inc.

5. Baker Hughes, Inc.

6. How can acquisitions in a given year exceed sales? When it comes to proved reserves, an exchange of properties is not a zero-sum game. Operators often have differing development plans for oil- and natural gas-bearing properties they purchase from or exchange with other operators. For example, when an operator purchases acreage that is adjacent to its producing wells, the operator can drill longer horizontal laterals and add more proved reserves.

7. The oil production estimates in this report use data reported on Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves. They are used to weight estimates used in developing total proved reserves, and they may differ slightly from the official EIA production data for crude oil and lease condensate for 2020 contained in the Petroleum Supply Annual 2020, DOE/EIA-0340(20).

8. The 12-month, first-of-the-month average spot price for natural gas at the Louisiana Henry hub.

9. Order Granting Authorization Under Section 3 Of The Natural Gas Act.

10.The natural gas production estimates in this report are based on data reported on Form EIA-23L, Annual Report of Domestic Oil and Gas Reserves. Estimates differ from our official production data for natural gas published in the Natural Gas Annual 2020, DOE/EIA-0131(20).

11. U.S. Energy Information Administration, U.S. Crude Oil and Natural Gas Proved Reserves, Year-End 2017, November 2018, pg. 18.

12. U.S. Energy Information Administration, Today in Energy, Hydraulically fractured horizontal wells account for most new oil and natural gas wells, January 30, 2018.

13. U.S. Energy Information Administration, U.S. Crude Oil and Natural Gas Proved Reserves, Year-End 2019, January 2021, Table 15.

14. U.S. Energy Information Administration, U.S. Crude Oil and Natural Gas Proved Reserves, Year-End 2019, January 2021, Table 15.

15. U.S. Energy Information Administration, U.S. Crude Oil and Natural Gas Proved Reserves, Year-End 2019, January 2021, Table 16.

Contact: Steven G. Grape or 202-586-1868