Abstract: A chemical kinetic model is developed for calibrating organic matter-generating oil and gas of Sha-3 member shale in Jiyang depression by using data from thermal simulation experiments. The profiles of hydrocarbon generation and expulsion in Chexi sub-sag are analyzed, and the concepts of threshold of oil generation, peak oil generation and threshold of hydrocarbon expulsion are discussed in detail. Based on these, the quantitative evaluation of the history of hydrocarbon generation and expulsion for three possible source rocks in Chexi sub-sag is conducted, indicating that the hydrocarbon expulsion time took place mainly in late or recent period since the deposition of Dongying formation in Chexi Sha-3 member that is the dominant oil sources in buried hill area. This is completely consistent with the period of fluid migration and accumulation determined by inclusion's uniform temperature. Thereby, the cognitions about the periods of hydrocarbon generation, expulsion and accumulation are validated one another.

Key words: Jiyang depression, organic matter, source rock, hydrocarbon expulsion, inclusion