75
Origin and Occurrence
the very large tar sand deposits all involve a combination of stratigraphic and structural traps, and
there are no very large (>4 × 10 9 bbl) oil sand accumulations either in purely structural or in purely
stratigraphic traps.
The potential reserves of bitumen that occur in tar sand deposits have been variously estimated
on a world basis as being in excess of 3 trillion (3 × 10 12 ) barrels and the reserves that have been
estimated for the United States have been estimated to be in excess of 52 million (52 × 10 6 ) barrels.
That commercialization has taken place in Canada does not mean that commercialization is imminent for other tar sand deposits. There are considerable differences between the Canadian and the
US deposits that could preclude across-the-board application of the Canadian principles to the US
sands (Speight, 1990).
Various definitions have been applied to energy reserves (Chapter 1) but the crux of the matter
is the amount of a resource that is recoverable using current technology. Although tar sands are not
a principal energy reserve, they certainly are significant with regard to projected energy consumption over the next several generations. Thus, in spite of the high estimations of the reserves of bitumen, the two conditions of vital concern for the economic development of tar-sand deposits are the
concentration of the resource, or the percent bitumen saturation, and its accessibility, usually measured by the overburden thickness. Recovery methods are based either on mining combined with
some further processing or operation on the oil sands in situ. The mining methods are applicable
to shallow deposits, characterized by an overburden ratio (i.e., overburden depth to thickness of
tar-sand deposit). For example, indications are that for the Athabasca deposit, no more than 15% of
the in-place deposit is available within current concepts of the economics and technology of openpit mining; this 10% portion may be considered as the proven reserves of bitumen in the deposit.
REFERENCES
Almon, W.R. 1974. Petroleum-forming reactions: Clay catalyzed fatty acid decarboxylation, PhD thesis.
University of Missouri-Columbia, Columbia, MO.
Atkinson, G. and Zuckerman, J.J. 1981. Origin and Chemistry of Petroleum. Pergamon Press, New York.
Bailey, N.J.L., Evans, C.R., and Milner, C.W.D. 1974. Applying petroleum geochemistry to search for oil:
Examples from Western Canada Basin. Bulletin of the American Association of Petroleum Geologists
58: 2284–2294.
Bailey, N.J.L., Jobson, A.M., and Rogers, M.A. 1973a. Bacterial degradation of crude oil: Comparison of field
and experimental data. Chemical Geology 11: 203–221.
Bailey, N.J.L., Krouse, H.H., Evans, C.R., and Rogers, M.A. 1973b. Alteration of crude oils by waters and
bacteria—Evidence from geochemical and isotope studies. Bulletin of the American Association of
Petroleum Geologists 57: 1276–1290.
Barker, C. 1980. Primary migration: The importance of water-mineral-organic matter interactions in the source
rock. In Problems of Petroleum Migration, W.H. Roberts and R.J. Cordell (Eds.). Studies in Petroleum
Geology. Bulletin No. 10. American Association of Petroleum Geologists, Tulsa, OK.
Barker, C. and Wang, L. 1988. Applications of pyrolysis in petroleum geochemistry: A bibliography. Journal
of Analytical and Applied Pyrolysis 13: 9–61.
Bates, R.L. and Jackson, J.L. 1980. Glossary of Geology. American Geological Institute, Falls Church, VA.
Bjorøy, M., Hall, P.B., Loberg, R., McDermott, A., and Mills, N. 1987. Hydrocarbons from nonmarine source rocks.
In Advances in Organic Geochemistry (Proceedings of 13th International Meeting on Organic Geochemistry,
Venice), Part 1, L. Mattavelli and L. Novelli (Eds.). Pergamon Press, Oxford, U.K., pp. 221–224.
Brooks, J. 1981. Organic Maturation Studies and Fossil Fuel Exploration. Academic Press, London, U.K.
Brooks, J. and Welte, D.H. 1984. Advances in Petroleum Geochemistry, Vol. I. Academic Press, New York.
Campbell, C.J. 1997. The Coming Oil Crisis. Multi-Science Publishing Company & Petroconsultants,
Brentwood, Essex, U.K.
Connan, J., Le Tran, K., and Van der Weide, B. 1975. Alteration of petroleum in reservoirs. Proceedings of the
9th World Petroleum Congress, Vol. 2. John Wiley & Sons, Inc., New York, pp. 171–178.
Demaison, G., Holck, A.J., Jones. R.W., and Moore, G.T. 1984. Predictive source bed stratigraphy: A guide to
region-al petroleum occurrence. Proceedings of the 11th World Petroleum Congress, Vol. 2. John Wiley
& Sons, Inc., New York, pp. 17–29.
Origin and Occurrence
the very large tar sand deposits all involve a combination of stratigraphic and structural traps, and
there are no very large (>4 × 10 9 bbl) oil sand accumulations either in purely structural or in purely
stratigraphic traps.
The potential reserves of bitumen that occur in tar sand deposits have been variously estimated
on a world basis as being in excess of 3 trillion (3 × 10 12 ) barrels and the reserves that have been
estimated for the United States have been estimated to be in excess of 52 million (52 × 10 6 ) barrels.
That commercialization has taken place in Canada does not mean that commercialization is imminent for other tar sand deposits. There are considerable differences between the Canadian and the
US deposits that could preclude across-the-board application of the Canadian principles to the US
sands (Speight, 1990).
Various definitions have been applied to energy reserves (Chapter 1) but the crux of the matter
is the amount of a resource that is recoverable using current technology. Although tar sands are not
a principal energy reserve, they certainly are significant with regard to projected energy consumption over the next several generations. Thus, in spite of the high estimations of the reserves of bitumen, the two conditions of vital concern for the economic development of tar-sand deposits are the
concentration of the resource, or the percent bitumen saturation, and its accessibility, usually measured by the overburden thickness. Recovery methods are based either on mining combined with
some further processing or operation on the oil sands in situ. The mining methods are applicable
to shallow deposits, characterized by an overburden ratio (i.e., overburden depth to thickness of
tar-sand deposit). For example, indications are that for the Athabasca deposit, no more than 15% of
the in-place deposit is available within current concepts of the economics and technology of openpit mining; this 10% portion may be considered as the proven reserves of bitumen in the deposit.
REFERENCES
Almon, W.R. 1974. Petroleum-forming reactions: Clay catalyzed fatty acid decarboxylation, PhD thesis.
University of Missouri-Columbia, Columbia, MO.
Atkinson, G. and Zuckerman, J.J. 1981. Origin and Chemistry of Petroleum. Pergamon Press, New York.
Bailey, N.J.L., Evans, C.R., and Milner, C.W.D. 1974. Applying petroleum geochemistry to search for oil:
Examples from Western Canada Basin. Bulletin of the American Association of Petroleum Geologists
58: 2284–2294.
Bailey, N.J.L., Jobson, A.M., and Rogers, M.A. 1973a. Bacterial degradation of crude oil: Comparison of field
and experimental data. Chemical Geology 11: 203–221.
Bailey, N.J.L., Krouse, H.H., Evans, C.R., and Rogers, M.A. 1973b. Alteration of crude oils by waters and
bacteria—Evidence from geochemical and isotope studies. Bulletin of the American Association of
Petroleum Geologists 57: 1276–1290.
Barker, C. 1980. Primary migration: The importance of water-mineral-organic matter interactions in the source
rock. In Problems of Petroleum Migration, W.H. Roberts and R.J. Cordell (Eds.). Studies in Petroleum
Geology. Bulletin No. 10. American Association of Petroleum Geologists, Tulsa, OK.
Barker, C. and Wang, L. 1988. Applications of pyrolysis in petroleum geochemistry: A bibliography. Journal
of Analytical and Applied Pyrolysis 13: 9–61.
Bates, R.L. and Jackson, J.L. 1980. Glossary of Geology. American Geological Institute, Falls Church, VA.
Bjorøy, M., Hall, P.B., Loberg, R., McDermott, A., and Mills, N. 1987. Hydrocarbons from nonmarine source rocks.
In Advances in Organic Geochemistry (Proceedings of 13th International Meeting on Organic Geochemistry,
Venice), Part 1, L. Mattavelli and L. Novelli (Eds.). Pergamon Press, Oxford, U.K., pp. 221–224.
Brooks, J. 1981. Organic Maturation Studies and Fossil Fuel Exploration. Academic Press, London, U.K.
Brooks, J. and Welte, D.H. 1984. Advances in Petroleum Geochemistry, Vol. I. Academic Press, New York.
Campbell, C.J. 1997. The Coming Oil Crisis. Multi-Science Publishing Company & Petroconsultants,
Brentwood, Essex, U.K.
Connan, J., Le Tran, K., and Van der Weide, B. 1975. Alteration of petroleum in reservoirs. Proceedings of the
9th World Petroleum Congress, Vol. 2. John Wiley & Sons, Inc., New York, pp. 171–178.
Demaison, G., Holck, A.J., Jones. R.W., and Moore, G.T. 1984. Predictive source bed stratigraphy: A guide to
region-al petroleum occurrence. Proceedings of the 11th World Petroleum Congress, Vol. 2. John Wiley
& Sons, Inc., New York, pp. 17–29.