Journal of Petroleum Geology, Vol.8,
No.2, pp. 229-232, 1985
©Copyright 2000 Scientific Press,
Ltd.
GEOLOGIC TIME AS A
PARAMETER IN ORGANIC METAMORPHISM AND VITRINITE REFLECTANCE AS AN
ABSOLUTE PALEOGEOTHERMOMETER: DISCUSSION
James J. Kohsmann +
+ Bellaire Research Laboratories,
Texaco USA, PO Box 425, Bellaire, TX. 77405, USA.
Experience in industrial applications
suggests that hydrocarbon maturation can be modelled using
first-order reaction kinetics. Recently, however, Price (1983)
concluded that first-order reactions were not of great importance
in the thermal breakdown of kerogens, and that most maturation is
strongly dependent only on the maximum temperature attained, not
on the length of heating time. The conclusion regarding the
inapplicability of first-order reaction theory to hydrocarbon
maturation was based in part on the non-linearity of log-linear
plots of the percent of remaining kerogen versus time.
The conclusion concerning the strong temperature- and weak
time-dependence of kerogen decomposition was based in part on the
observation that constant-temperature pyrolysis data often show
negligible reactions for times on the order of hundreds of hours.
It can be shown that the observations upon which these
conclusions are, in part, based are compatible with first-order
reaction theory.