Technically Recoverable Shale Oil and Shale Gas Resources: An Assessment of 137 Shale Formations in 41 Countries Outside the United States
Release date: June 10, 2013 Updated: June 13, 2013 Table 5 corrected
This report provides an initial assessment of shale oil resources and updates a prior assessment of shale gas resources issued in April 2011. It assesses 137 shale formations in 41 countries outside the United States, expanding on the 69 shale formations within 32 countries considered in the prior report. The earlier assessment, also prepared by Advanced Resources International (ARI), was released as part of a U.S. Energy Information Administration (EIA) report titled World Shale Gas Resources: An Initial Assessment of 14 Regions Outside the United States.1
There were two reasons for pursuing an updated assessment of shale resources so soon after the prior report. First, geologic research and well drilling results not available for use in the 2011 report allow for a more informed evaluation of the shale formations covered in that report as well as other shale formations that it did not assess. Second, while the 2011 report focused exclusively on natural gas, recent developments in the United States highlight the role of shale formations and other tight plays as sources of crude oil, lease condensates, and a variety of liquids processed from wet natural gas.
As shown in Table 1, estimates in the updated report taken in conjunction with EIA's own assessment of resources within the United States indicate technically recoverable resources of 345 billion barrels of world shale oil resources and 7,299 trillion cubic feet of world shale gas resources. The new global shale gas resource estimate is 10 percent higher than the estimate in the 2011 report.
|ARI report coverage||2011 Report||2013 Report|
|Number of countries||32||41|
|Number of basins||48||95|
|Number of formations||69||137|
|Technically recoverable resources, including U.S.|
|Shale gas (trillion cubic feet)||6,622||7,299|
|Shale / tight oil (billion barrels)||32||345|
|Note: The 2011 report did not include shale oil; however, the Annual Energy Outlook 2011 did (for only the U.S.) and is included here for completeness.|
Although the shale resource estimates presented in this report will likely change over time as additional information becomes available, it is evident that shale resources that were until recently not included in technically recoverable resources constitute a substantial share of overall global technically recoverable oil and natural gas resources. The shale oil resources assessed in this report, combined with EIA's prior estimate of U.S. tight oil resources that are predominantly in shales, add approximately 11 percent to the 3,012 billion barrels of proved and unproved technically recoverable nonshale oil resources identified in recent assessments. The shale gas resources assessed in this report, combined with EIA's prior estimate of U.S. shale gas resources, add approximately 47 percent to the 15,583 trillion cubic feet of proved and unproven nonshale technically recoverable natural gas resources. Globally, 32 percent of the total estimated natural gas resources are in shale formations, while 10 percent of estimated oil resources are in shale or tight formations.
Wet natural gas
(trillion cubic feet)
|Outside the United States|
|Shale oil and shale gas unproved resources||287||6,634|
|Other proved reserves 1||1,617||6,521|
|Other unproved resources 2||1,230||7,296|
|Increase in total resources due to inclusion of shale oil and shale gas||10%||48%|
|Shale as a percent of total||9%||32%|
|EIA shale / tight oil and shale gas proved reserves 3, 4||n/a||97|
|EIA shale / tight oil and shale gas unproved resources5||58||567|
|EIA other proved reserves6||25||220|
|EIA other unproved resources5||139||1,546|
|Increase in total resources due to inclusion of shale oil and shale gas||35%||38%|
|Shale as a percent of total||26%||27%|
|Shale / tight oil and shale gas proved reserves||n/a||97|
|Shale / tight oil and shale gas unproved resources||345||7,201|
|Other proved reserves||1,642||6,741|
|Other unproved resources||1,370||8,842|
|Increase in total resources due to inclusion of shale oil and shale gas||11%||47%|
|Shale as a percent of total||10%||32%|
1 Oil & Gas Journal, Worldwide Report, December 3, 2012.
2 Sources: U.S. Geological Survey, An Estimate of Undiscovered Conventional Oil and Gas Resources of the World, 2012, Fact Sheet 2012-3028, March 2012; U.S. Geological Survey, Assessment of Potential Additions to Conventional Oil and Gas Resources of the World (Outside the United States) from Reserve Growth, 2012, Fact Sheet 2012-3052, April 2012.
3 U.S. Energy Information Administration, U.S. Crude Oil, Natural Gas, and NG Liquids Proved Reserves With Data for 2010, Table 14. Shale natural gas proved reserves, reserves changes, and production, wet after lease separation, 2010; year-end reserves, August 1, 2012.
4 Proved tight oil reserves not broken out from total year end 2010 proved reserves; will be provided in future reporting of proved reserves.
5 Source: U.S. Energy Information Administration, Annual Energy Outlook 2013 Assumptions report, Tables 9.1 through 9.5.; wet natural gas volumes were determined by multiplying the AEO2013 dry unproved natural gas resource estimate by 1.045 so as to include NGPL.
6 Ibid. Table 5: Total natural gas proved reserves, reserves changes, and production, wet after lease separation, 2010; equals year-end figure minus the wet shale gas reserves reported for the year-end.
BOX 1: TERMINOLOGY: SHALE OIL AND TIGHT OIL
Although the terms shale oil.2 and tight oil are often used interchangeably in public discourse, shale formations are only a subset of all low permeability tight formations, which include sandstones and carbonates, as well as shales, as sources of tight oil production. Within the United States, the oil and natural gas industry typically refers to tight oil production rather than shale oil production, because it is a more encompassing and accurate term with respect to the geologic formations producing oil at any particular well. EIA has adopted this convention, and develops estimates of tight oil production and resources in the United States that include, but are not limited to, production from shale formations. The ARI assessment of shale formations presented in this report, however, looks exclusively at shale resources and does not consider other types of tight formations.