地史过程中烃源岩有机质丰度和生烃潜力变化的模拟计算

在同时考察源岩中有机质因生、排烃而损失和无机质因成岩作用而失重的基础上，模拟计算了地史过程中，随有机质类型、初始有机质丰度、成熟度及排烃效率的改变，烃源岩有机质丰度和生烃潜力的变化，探讨了有机碳恢复系数及生烃潜力损失率的可能变化范围。结果表明，地史过程中，有机质生烃潜力和有机质丰度的变化主要取决于源岩的生、排烃效率，对性质偏差的有机质，有机质的实测丰度随演化程度的增高不降反升；而对位于高成熟阶段的优质有机质，有机碳的恢复系数可达2以上；随有机质类型变好和成熟度升高，生烃潜力损失率增高；一般情况下，有机质生烃潜力的恢复幅度比有机质丰度的恢复大得多。

Simulating Calculation of the Variations of Organic Matter Abundance and Hydrocarbon-generating Potential during Geological Processes

Based on the examination of the losing of organic matter due to the generation and expulsion of hydrocarbons and the weight loss of inorganic matter due to diagenesis and water expulsion, this paper presents calculations of the variations of organic matter abundance and hydrocarbon-generating potential along with changes of the organic matter type, the initial organic carbon content, the maturity degree and hydrocarbon expulsion efficiency in the geologic history; and discusses the possible variation ranges of the restoring coefficient of organic carbon and the loss ratio of hydrocarbon potential. The results indicate that the variations of organic matter abundance and hydrocarbon-generating potential during geological processes depend mainly upon the efficiency of hydrocarbon generation and expulsion. For type I organic matter, the measured content of organic matter increases rather than decreases with the deepening of evolution, whereas for type I organic matter, the restoring coefficient of organic carbon can be as high as 2. The loss ratio of hydrocarbon potential increases with meliorating organic type and increasing maturity. Generally speaking, the restoring extent of hydrocarbon potential of organic matter is much higher than that of organic carbon.