Driving forces of hydrocarbon expulsion from carbonate source rocks are mainly hydrothermal pressurization and hydrocarbon generation pressurization due to the early diagenesis-consolidation of carbonates.A numerical relation model between pressurization values and temperatures is built through simulation experiments of temperature-pressure relationship on carbonate source rock samples with various organic carbon contents.Experiment results show that hydrocarbon generation pressurization values are much higher than hydrothermal pressurization values in the process of hydrocarbon generation in carbonate source rocks.The dynamic forces driving hydrocarbon expulsion from carbonate source rocks are mainly influenced by organic matter abundance of the source rocks and temperature.As for the same source rocks

hydrocarbon generation pressurization values increase rapidly along with the increasing thermal evolution level.Hydrocarbon generation pressurization values would be in positive correlation with organic carbon contents of mples when the thermal evolution levels are equivalent.If the organic carbon content of source rocks is too low

hyrocarbon generation pressurization would not be high enough for effectively driving hydrocarbon expulsion from the source rocks.Since water content in carbonate source rocks is generally very low

hydrocarbon generation pressurization

especially gas generation pressurization would be more important to hydrocarbon expulsion.Therefore

carbonate source rocks follow the dynamic pattern of hydrocarbon generation-pressurization-overpressure-pressure release-hydrocarbon expulsion.