LITHOLOGICAL AND THERMAL FEATURES OF MITROVO FORMATION (T2-3) IN CENTRAL SOUTHERN PART OF THE MOESIAN PLATFORM (BULGARIA): PRECONDITIONS FOR A HYDROCARBON GENERATION

11th International Multidisciplinary Scientific GeoConference SGEM2011, www.sgem.org, SGEM2011 Conference Proceedings/ ISSN 1314-2704, June 20-25, 2011, Vol. 1, 1221-1228 pp

ABSTRACT

The Triassic sediments in the Moesian Platform are very well explored. The study area
is in the Bulgarian territory and covers central part of the South Moesian Platform
Margin and adjoining zone to the north. The Triassic rocks there are characterized by
considerable diversity, thickness and burial depths. Among them Mitrovo Fm. (T2lad-
T3crn) contains mostly silty-argillacious carbonates with a fair to good organic matter
content.

The Pre-Jurassic erosion reached different levels up to Middle Triassic, Lower Triassic
and even Paleozoic rocks. Therefore, the denudation partly or completely cut down the
sediments of Mitrovo Fm. in central and eastern part of the study area. The reduced
thicknesses vary from few ten meters to 130 m.

Maturity indices demonstrate that the Mitrovo Fm. sediments are Late- to Postmature.
The highest values are measured in the border area of the South Moesian Platform
Margin and Forebalkan. Thermal history reconstructions based on constant scenarios
show relatively smooth distribution of the heat flow in the range of 50-55 mW/m2.

The final goals of the paper are to investigate and analyze the lithology and thermal
features of Mitrovo Fm. as important preconditions for a hydrocarbon generation. The
main focus is on a narrow distribution, lithological heterogeneity and higher maturity of
the sediments as hydrocarbon generation limitations.

Keywords: Moesian Platform, Mitrovo Fm., lithological heterogeneity, thermal maturity, hydrocarbon generation limitations.