Modeling of geothermal evolution of sedimentary rocks in East Herzegovina based on vitrinite reflectance

Abstract

This paper presents the first results of the geothermal evolution modeling in East Herzegovina based on vitrinite reflectance calculations and measurements. Modeling of burial and geothermal was performed using "SimpleMat" software with well known kinetic model of vitrinite reflectance - EASY % Ro. By fitting the calculated reflectance values with mean measured vitrinite reflectances, it was concluded that there was erosion of some 900 m in the area, and that first possible petroleum generation could have started some 100 Ma ago. According to final calibration model that includes additional thickness and subsequent erosion of Paleogene sequence, the Upper Triassic sediments should have maturity from 0.70 to 1.1 % Rr, Lower Jurassic from 0.62 to 0.70 % Rr, whereas Upper Cretaceous sediments should have values from 0.40 to 0.60 % Rr, which is in accordance with measured vitrinite reflectance in 23 samples. Assuming that beginning of oil window in the East Herzegovina correspond to the vitrinite reflectance of 0.50 % Rr, all analyzed Mesozoic samples are at the initial stage of catagenesis ("oil window"), while Cenozoic sediments are at the stage of diagenesis.

Keywords

• petroleum
• thermal maturity
• geothermal modeling
• vitrinite reflectance
• east herzegovina