President’s Column – May 2013

Title: What’s in a name or nickname?

Author: Debra Higley

Publication: The Outcrop, May 2013, p. 6, 8

MayPresThe photograph above by Mike Lewan is from within the Athabasca oil (tar) sands accumulation of northeastern Alberta. It shows me standing to the right of Mike Ranger on an outcrop of Lower Cretaceous Mannville Group composed mostly of cross-bedded medium-grained point-bar sand that is cemented by bitumen. Fresh slump structures are black (middle left) and outcrop surfaces oxidize to gray.

What’s in a name or nickname? Certainly slang terms for hydraulic fracturing have negative connotations to many that blur these processes that decrease oil imports from other countries and enhance U.S. recovery of oil and gas. Another touchy name is tar sands. Technically the tar sands are not oil, tar, or extra-heavy oil, and they are not always sand. They can include porous sandstone and carbonate, and can also contain some oil and gas. The “tar” is instead bitumen, basically the long-chain and polycyclic hydrocarbons that don’t readily degrade. The tar is what is left after the aerobic and (or) anaerobic bacteria buffet. Heavy oil is defined as having a density between 10o and 25o API gravity, and extra-heavy oil (bitumen) is less than 10o API; these deposits occur in
more than 70 countries across the world (IOCC, 1983; Schenk and others, 2006). The best known bitumen accumulations are those of Alberta, Canada, partly because of their massive volume that is estimated at 168.6 billion barrels (BB) recoverable (ERCB, 2012), and also the economic, environmental, and political concerns regarding production, refining, reclamation, and export (especially to the U.S.). The ERCB publication is also a good source of information on conventional and unconventional reserves and resources of Alberta. Bitumen sands may also contain elevated levels of sulfur and heavy metals, when compared to those of oil. My main interests in bitumen sands are resource assessment and “genealogy”, or what petroleum source rock(s) begat the accumulations (Higley and others, 2009).

In-place bitumen estimates for 29 major accumulations in Alabama, Alaska, California, Texas, Utah, and Wyoming is about 54 billion barrels (Schenk and others, 2006). In-place resources for two bitumen accumulations in Wyoming total 120 million barrels (MB) measured and 70 MB speculative (IOCC, 1983; Schenk and others, 2006). Utah has the largest number of and total size of accumulations, which are located mainly in the Uinta Basin of northeastern Utah (Blackett, 1996), and in central-southeastern Utah (http://geology.utah.gov/emp/tarsand/index.htm). Estimates of in-place resources for Utah accumulations range from about 11.9 BB measured and 6.8 BB speculative (IOCC, 1983) to 14-15 BB in place and 23-28 BB potential (Gwynn, 2007; Gwynn and Hanson, 2009).


References
Blackett, R. E., 1996, Tar-sand resources of the Uinta Basin, Utah: a catalog of deposits: Utah Geological Survey Open-File Report 335, 128 p. http://ugspub.nr.utah.gov/publications/open_file_reports/OFR-335.pdf

ERCB, 2012, Alberta’s Energy Reserves 2011 and Supply/Demand Outlook 2011-2021, Alberta Energy and Utilities Board, Statistical Series, ST98-2012, 290 p. http://www.ercb.ca/sts/ST98/ST98-2012.pdf

Gwynn, J. W., 2007, Taking another look at Utah’s tar sand resources: Utah Geological Survey, January 2007 Survey Notes article, 2 p. http://geology.utah.gov/surveynotes/articles/pdf/tarsand_resources_39-1.pdf

Gwynn, J. W., and Hanson, F. V., 2009, Annotated bibliography of Utah tar sands and related information: Utah Geological Survey Open-File Report 503, 140 p. http://geology.utah.gov/online/ofr/ofr-503.pdf

Higley, Debra K., Lewan, Michael D., Roberts, Laura N.R., and Henry, Mitchell, 2009, Timing and petroleum sources for the Lower Cretaceous Mannville Group oil sands of Northern Alberta based on 4-D modeling: American Association of Petroleum Geologists
Bulletin, v 93 no. 2, 28 p.

IOCC (Interstate Oil Compact Commission), 1983, Major tar sand and heavy oil deposits of the United States: Interstate Oil Compact Commission, p. 85-116.

Schenk, C.J., Pollastro, R. M., and Hill, R. J., 2006, Natural bitumen resources of the United States: U. S. Geological Survey Fact Sheet 2006-3133, 2 p. http://pubs.usgs.gov/fs/2006/3133/pdf/FS2006-3133_508.pdf.