RELATIONSHIP BETWEEN COMPOSITION OF KEROGEN AND THEIR ACTIVATION ENERGY DISTRBUTIONS FOR THE GENERATION OF PETROLEUM IN BLOCK NC-X EASTREN SIRTE BASIN - LIBYA

Identifying the kerogen type is essential for the evaluation of the petroleum potential of the sediments dominated by terrestrial organic matter in exploration areas. This will improve the modeling of the generation history of the source rock sediments. Prime objective of this study is to investigate the Upper Cretaceous and Lower Cretaceous potential source rocks in the study area and provide a detailed evaluation of the source rock quality and the maturation levels. The knowledge of the petroleum generation and the characteristics of the source rock sediments is one of the main factors in the exploration success of an area. Cuttings samples were analyzed from the Upper and Lower Cretaceous source rocks sediments (Shale) for total organic carbon content (TOC) and Rock Eval pyrolysis in fourteen (14) wells in the study area Sirte basin. Spore coloration (SC), vitrinite reflectance (Vr) and basin modeling techniques were used in this study. Activation energy (E) distribution and pre exponential factor (A) of forty (40) shale samples of varying composition, rank, age and origin are discussed. The petrography and the rank of the sediments have been correlated to the distribution of activation energy and hydrogen index (HI). Hydrogen index is positively correlated to vitrinite reflectance (Vr) and liptinitic group, in particular, the vitrinite maceral has a strong influence on the hydrogen index HI. Hydrogen Index inertintic group has a negative effect on the HI, the activation energy increase with the increase of thermal maturity. The kinetic parameters are utilized to extrapolate geologic conditions to compare at what temperature ranges oil generation is predicted to occur. The discrete activation energies were used to calculate the oil generation at lab and geologic heating rate. The analyzed samples exhibited principle activation energies of 50 -62 kcal/mole. Shale samples have shown in some cases differences in the derived kinetic parameters.