Journal of Petroleum Geology, Vol.7, No.1, pp.109-112, 1984

©Copyright 2000 Scientific Press, Ltd.

A PROBLEM WITH ESTIMATING THE PSEUDO-ACTIVATION
ENERGY OF KEROGEN THERMAL MATURATION FROM CONNAN'S TIME-TEMPERATURE RELATION IN OIL GENESIS

Charles E. Barker*

*U.S. Geological Survey, Box 25046, Denver Federal Center, Denver, CO 80225.

Abstract

Connan's time-temperature relation in oil genesis as derived from first-order reaction kinetics is algebraically correct, but its application to natural petroleum generation is invalidated by the assumption that the ratio of initial kerogen concentration to degraded kerogen concentration is constant from deposition to the initiation of intense oil generation. The ratio can only remain constant if no reaction is occurring and, therefore, Connan's data on "reaction time" in petroleum generation (assumed to be the age of the sediment) only measures the time elapsed since the system formed. Thus, the widely cited pseudo-activation energy of 11-14 kcal/mole computed from Connan's equation for the start of oil generation from kerogen is meaningless.