煤中有机质二次生烃迟滞性及其反应动力学机制

采用自然成熟度系列与其预热残渣系列样品相结合方式, 通过热解模拟方法, 对煤中有机质二次生烃迟滞性显现特征和化学反应动力学机制进行了探讨.结果表明: 二次生烃起始成熟度增高, 二次生烃峰位成熟度呈规律性后移, 二次生烃作用“死线”位于R_o=4.0 %左右; 二次生烃峰位成熟度与起始成熟度之差随起始成熟度的增高呈抛物线式演化, 二次生烃的绝对迟滞性和相对迟滞性均呈阶段性演化, 由此可对二次生烃迟滞深度进行预测; 二次生烃半峰宽随起始成熟度呈阶段性演化, 暗示二次生烃起始成熟度位于生油高峰附近的烃源岩, 其生烃量可能相对较大.同时, 原始样品平均活化能的演化经历了4个阶段, 它们与热解生烃量及二次生烃迟滞性的阶段性演化特征高度吻合, 揭示出二次生烃作用严格受控于反应动力学的地球化学机制. 

LAGGING AND REACTION KINETIC MECHANISM OF HYDROCARBON REGENERATION FROM ORGANIC MATTERS IN COALS

In this study, the coal sample series are analyzed with both natural and artificial maturity series. Then the pyrolytic simulation method is employed to address the lagging and reaction kinetic mechanism of the hydrocarbon regeneration from the organic matters in coals. This analysis indicates that the initial maturity of the hydrocarbon regeneration increased and the peak maturity of the hydrocarbon regeneration shifted backward in a regular pattern with the "deadline" of this generation standing at about 4.0% (R_o). The difference between the peak and initial maturities of the hydrocarbon regeneration grows in a parabola pattern with the increasing initial maturity. In addition, the absolute and the relative laggings of the hydrocarbon regeneration evolve stage by stage. Therefore, the lagging range of the hydrocarbon regeneration might be forecasted. The stage-like variation of the half-peak width curve of the hydrocarbon regeneration with the initial maturity inferred the location of the initial maturity of the hydrocarbon regeneration in the hydrocarbon source rocks, near the hydrocarbon generation peak, which may yield a relatively great mount of hydrocarbon. At the same time, the mean activation energy of the coal samples with original maturity has evolved through four stages, highly matching the pyrolytic hydrocarbon generation and the stage evolution features of the lagging of the hydrocarbon regeneration. This perfect matching indicates the strict constraint of the geochemical mechanism of the reaction kinetics on the hydrocarbon regeneration.