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USGS revises world resource estimates Publishes new assessment of remaining technically recoverable resources in possible undiscovered conventional oil and gas fields Alan Bailey Petroleum News
In a report published April 18 the U.S. Geological Survey has provided a new assessment of worldwide undiscovered, technically recoverable oil and gas. The assessment does not include so-called unconventional resources such as shale oil and gas, and does not include data for the United States.
The agency has estimated remaining undiscovered resources from 171 worldwide geologic provinces to be 565 billion barrels of oil, 5,606 trillion cubic feet of natural gas and 167 billion barrels of natural gas liquids. No ranges of uncertainty are provided for these overall figures, although ranges provided for individual regions within the assessment indicate some significant geologic uncertainty relating to the data.
“By placing this information in the public domain, government leaders, investors, public and private corporations, and citizens have a common information base for planning and decisions that affect the global environment and market place,” said USGS Director Marcia McNutt when announcing the publication of the assessment.
The last USGS worldwide assessment, published in 2000, estimated undiscovered resources of 649 billion barrels of oil, 4,660 tcf of gas and 207 billion barrels of natural gas liquids in 128 geologic provinces.
Four regions Just four regions account for 75 percent of the undiscovered oil, USGS says. These regions consist of South America and Caribbean with 126 billion barrels; sub-Saharan Africa with 115 billion barrels; the Middle East and North Africa with 111 billion barrels; and the Arctic provinces of North America with 61 billion barrels. All of the world’s regions are likely to have significant undiscovered gas resources, USGS says.
Also of note in the overall results from the assessment are the combined regions of the Arctic Ocean and the former Soviet Union, with an estimated range of 16 billion to 117 billion barrels of oil, and a mean estimate of 66 billion barrels. This combined region has a potential range of 398 tcf to 4,056 tcf of natural gas, with a mean of 1,623 tcf, and a potential range of 10 billion to 97 billion barrels of natural gas liquids, with a mean of 8 billion barrels.
North America, excluding the United States but including Mexico, Canada and several Arctic provinces, has a potential range of 26 billion to 208 billion barrels of oil, with a mean estimate of 83 billion barrels. This region has a range of 160 tcf to 1,510 tcf of natural gas, with a mean of 574 tcf, and 4 billion to 56 billion barrels of natural gas liquids, with a mean of 19 billion barrels.
By comparison, USGS has previous assessed a mean volume of 27 billion barrels of undiscovered, technically recoverable conventional oil onshore in the United States, while the Bureau of Ocean Energy Management has assessed a mean of 89 billion barrels of undiscovered conventional oil in the U.S. outer continental shelf. Those figures add to a total estimate of 116 billion barrels of undiscovered, recoverable, conventional oil for the entire United States.
The corresponding figures for U.S. conventional natural gas are 388 tcf onshore and 398 tcf on the outer continental shelf, leading to a U.S. total of 786 tcf.
Important to understand Having just visited Brazil to promote strategic partnerships in energy development, Secretary of the Interior Ken Salazar commented on the importance to the United States of an understanding of worldwide resources. USGS thinks that nearly half of the undiscovered South American and Caribbean oil resource lie offshore Brazil.
“While we continue to focus our efforts on ways to continue to grow domestic energy production for America and further reduce our dependence on foreign oil, better knowledge of untapped resource potential all around the world will help us make better decisions regarding both domestic and global energy policy and resource management,” Salazar said. “In particular, this assessment underscores the importance of continuing to strengthen our energy partnerships in the Western Hemisphere with nations like Brazil, where we are working closely with industry and government to share best practices on offshore drilling safety and to enhance the energy security of both our countries.”
Methodology The USGS assessment method involves using a geologic understanding of geologic provinces within each region to define petroleum systems within the provinces and hence identify assessment units — mapable volumes of rocks with common geologic traits. The USGS scientists assess possible ranges of oil and gas volumes within each assessment unit and then statistically combine the results to derive resource volumes for provinces and regions. In this new worldwide assessment the scientists defined 313 assessment units.
USGS says that it is conducting a separate study to assess undiscovered unconventional oil and gas.
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