--> Abstract: Simulated Geothermal Maturation of Athabasca Bitumen, by A. E. George, R. C. Banerjee, G. T. Smiley; #90972 (1976).

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Abstract: Simulated Geothermal Maturation of Athabasca Bitumen

A. E. George, R. C. Banerjee, G. T. Smiley

Athabasca bitumen extracted from the tar sand was subjected to thermal treatment of increasing severity under reducing conditions (435-460° C, 2,000 psi hydrogen pressure and increasing reaction periods). The generation and change in relative distribution of various hydrocarbons (saturates, monoaromatics, diaromatics, and polyaromatics), sulfur compounds, and other polar components were followed by a separatory scheme involving distillation, liquid-solid chromatography, gas chromatography with flame ionization and microcoulometric sulfur detectors, as well as mass spectrometry. The degradation products were compared with other Cretaceous bitumens and oils that lie in the Western Canada tar belt and have different degrees of maturity. These were the Cold Lake bitumen obtained at a depth of 1,500 ft or 457 m), the Lloydminster (a heavy oil obtained at a depth of 1,900 ft or 579 m), and the Medicine River (a light oil obtained at 7,500 ft or 2,286 m).

Hydrocracking converted the bitumen to material similar to the more mature Cretaceous oils. Distinct groups of hydrocarbons and sulfur compounds were generated selectively. The dinuclear aromatic fractions and their associated sulfur compounds were of particular interest and were studied in detail. The isoprenoid hydrocarbons and normal alkanes also were studied. Pristane and phytane were not present in substantial quantities, but other isoprenoids of lower molecular weight were more significant. Considerable amounts of pristane and phytane appeared in the presence of a catalyst which indicates that they require certain conditions for their formation. Optical activities of the investigated oils and the bitumen hydrocracking products showed interesting analogies.

In general the different evidences of chemical composition indicate that the Athabasca bitumen is an immature material.

AAPG Search and Discovery Article #90972©1976 AAPG-SEPM Annual Convention and Exhibition, New Orleans, LA