IMPACTS OF VARIOUS TOC DISTRIBUTIONS ON HYDROCARBON GENERATION

This study used numerical basin modeling methods to examine how variou s total organic carbon content (TOC) distributions in formations, with a fixed average TOC, impact the overall oil and gas generation abilit y. Different geological and geochemical conditions, such as thickness and burial depth of the source formation, thermal gradient, organic ri chness, degree of spread, and types of kerogen are considered in this investigation. The results show that there is a significant impact on the overall oil and gas generation capability, especially when the sou rce rocks are in the peak generation windows. The magnitudes of oil an d gas generation rates can vary by up to 5-10 times in some cases. The general rules are that the more dispersion of TOC in the formation, o r the thicker the formation and the greater the thermal gradient, the larger the difference of generation rates between the distributions wh ich favor hydrocarbon generation. Therefore, in addition to the averag e TOC richness, the TOC distribution in a source rock formation must a lso be considered when the petroleum potential of a basin is evaluated .