--> ABSTRACT: Effects of Heating Rates of Hydrocarbon Generation and Occurrence, by M. Arif Yukler and Erik Thomsen; #91022 (1989)

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Effects of Heating Rates of Hydrocarbon Generation and Occurrence

M. Arif Yukler, Erik Thomsen

Hydrocarbon generation from kerogen was erroneously considered to be directly related to maturity of organic matter, commonly measured in terms of vitrinite reflectance. Studies during the last 7 years in over 100 basins, however, clearly show that vitrinite reflectance values are more sensitive to time and that generation of hydrocarbons is more sensitive to temperature (provided that temperatures are above a threshold value).

Peak oil generation for a typical type II kerogen is determined to occur at 1.05, 0.90, 0.75, 0.70, 0.67, 0.74, 0.60, 0.58, and 0.55% Ro values under heating rates of 0.5°, 1°, 2°, 3°, 4°, 5°, 10°, 20°, and 40°C/m.y., respectively. Heating rates ranging from 1.5° to 3°C/m.y. are normal heating rates under which peak oil generation occurs between 0.70 and 0.80% Ro. Vitrinite reflectance values are higher for low heating rates (< 1°C/m.y.) such as in the north German Zechstein basin and the Georges Bank, and will be lower for high heating rates (> 5°C/m.y.) such as in the Gulf Coast, the Santa Maria basin, and the Central Graben, North Sea.

Hydrocarbon generation also occurs at different temperatures as a function of heating rates. Peak oil generation occurs at 120°, 124°, 128°, 131°, 135°, 140°, 145°, and 150°C under the above heating rates, respectively. Dry gas generation occurs at temperatures ranging from 142° to 168°C under heating rates of 0.5° to 40°C/m.y.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.