The chemical kinetic models are widely applicable to study of organic
matter evolution in sedimentary rocks during catagenesis. Such models
are used to reconstruct the dynamics and spatial position of main zone
s of hydrocarbon generation in sedimentary basins. The commonest appro
ach represents the process of hydrocarbon formation as a series of par
allel independent reactions. More traditionally these questions were c
onsidered in detail using analysis of evolution of chemical compositio
n of organic matter. The scales of catagenesis, reflecting the spatial
changes of intensity of gaseous and liquid hydrocarbon generation are
developed in detail. Of interest is comparison of these approaches by
the example of well-known Mesozoic deposits in West Siberia, for whic
h one of the most substantiated scales of catagenesis zonation is deve
loped. Four samples from the Urnenskaya and Kamennaya areas were studi
ed to determine kinetic parameters. Previously the samples were extrac
ted with chloroform and then were pyrolyzed at linearly increasing tem
perature at an average rate of 24.45 K/s. The one-stage model with ind
ependent reactions of first order was used to calculate kinetic parame
ters and to simulate catagenesis zonation. It was assumed that the fre
quency factor is constant for all reactions and the initial weight of
the components by activation energy is distributed according to the Ga
uss law. The calculations of spatial positions of the main zone of hyd
rocarbon generation were made using three values of temperature gradie
nt of 30, 40 and 50 K/km. The range of intensive generation is 1.5 to
4.5 km, which corresponds to the place of main zone of gas and oil for
mation for the Mesozoic deposits of West Siberia and does not include
deep zone of gas generation. Probably it results from multiple stages
of the real process of hydrocarbon generation and the formation of int
ermediate, thermally more stable components, leading expansion of a re
al range of intensive generation.