MODELLING HYDROCARBON GENERATION IN THE PALAEOZOIC
AND MESOZOIC SUCCESSIONS IN SE POLAND AND NW UKRAINE
P. Kosakowski1, M. Wróbel1 and P.
1 Faculty of Geology, Geophysics
and Environmental Protection, AGH
University of Science and Technology, al. Mickiewicza
30, 30-059 Kraków, Poland.
2 Institute of Geological
Academy of Sciences, ul.
Twarda 51/55, 00-818 Warsaw,
* Corresponding author, email: email@example.com
The Lower Palaeozoic succession in SE Poland and NW Ukraine has source rock potential, particularly
the Ordovician and Silurian which contain oil-prone Type II kerogen. The thermal
maturity of these units ranges from early to late-phase oil window (locally
up to gas window). Within the Mesozoic succession, source rock potential is
highest in the Middle Jurassic which has TOC of up to 26 wt% and a genetic potential
of up to 39 mg/g of rock, with organic matter dominated by gas-prone Type III
kerogen. In SE Poland, the organic matter in
this unit is generally immature, whereas maturities in NW Ukraine are sufficient
for hydrocarbon generation to occur.
Modelling of hydrocarbon generation suggested that petroleum in Lower
Palaeozoic source rocks began to be generated in the Early Carboniferous.
Peak generation took place from the late Visean to the early Namurian, and terminated
either as a result of source rock depletion or Variscian inversion. Expelled
hydrocarbons migrated during post-Carboniferous and Mesozoic uplift. Middle
Jurassic source rocks in SE Poland have only
reached the early oil window. Higher thermal maturities in the Ukraine
resulted in hydrocarbon generation and expulsion. This took place after Miocene
burial and maturation.
A number of small hydrocarbon accumulations occur in Mesozoic
reservoirs in SE Poland / NW Ukraine, and hydrocarbons
have migrated from Cambrian and Ordovician source rocks. However, the prospectivity
of the study area is reduced as a result of phases of uplift and intense erosion
which allowed hydrocarbons to escape from structural traps.
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