Petroleum Generation and Expulsion Kinetics: A Case Study of the Sahejie Formation Source Rocks from Linnan Sag of Huimin Depression

Key words: 
• source rock

Abstract: This paper has introduced an approach which is based on the kinitics method and the software GOREvaluation for quantitative assessment of petroleum generation and expulsion of source rocks through a case study of Sahejie Formation of Linnan sag, Huimin Depression. The key points of the present approach include: an investigation of petroleum generation kinetics parameters of typical source rocks based on their thermal pyrolysis data carried out in a gold tubeautoclave; an investigation of the petroleum generation amount (Hpm) when oil begins to be expulsed from its source rock by combining the modeling results with the plot of EOM/TOCdepth of the source rocks from the Linnan sag; and an establishment of representative geochemical parameters of different types of source rocks by analyzing the available geochemical data. The petroleum generation and expulsion history of the three sets of source rocks from the Linnan Sag (Es13 dark mudstone, Es233 dark mudstone and Es233 dark shale) were investigated by this approach. The results have shown that the Hpm values of the Es233 dark shale and the Es233 dark mudstone are 150 mg/g 与170 mg/g, respectively. The oil threshed and oil expulsion threshed of the Es233 dark shale from the Well X101 occurred at 20 Ma and 13Ma; the Es233 dark mudstone at 19 Ma and 10 Ma; and the Es13 dark mudstone at 8 M and 2 Ma, respectively. The oil generation threshed of the three types of source rocks all occurs at about 0.55% of Easy Ro, but their oil expulsion threshed varies extensively, from 0.61% to 0.69% of EasyRo. It is believed that the merits of the present approach lie in that it avoids enactment of complicated oil expulsion parameters and explanation for oil expulsion mechanism and the results can be applied to quantitative assessment of petroleum generation and expulsion of source rocks, determination of effective source rocks and prediction of petroleum resources.