【摘要】 根据有机碳质量守恒原理,建立反映有机碳质量变化的有机碳质量补偿系数数学模型;综合考虑有机碳生烃、排烃和岩石失重过程对有机碳含量的影响,建立计算有机碳含量变化的数学模型。采用正演方法,模拟计算不同类型烃源岩在不同演化阶段和不同排烃效率下有机碳质量补偿系数和有机碳含量值。计算结果表明,有机碳质量补偿系数与烃源岩有机质类型、热演化程度和排烃效率有关,Ⅰ型、Ⅱ1型、Ⅱ2型和Ⅲ型有机质烃源岩的有机碳质量补偿系数最大值分别为2.104、1.360、1.169和1.099。不同类型泥质烃源岩都存在排烃效率阀值,Ⅰ型为20%、Ⅱ1型为30%、Ⅱ2型和Ⅲ型为60%,排烃效率小于阀值时,残余有机碳含量普遍大于原始有机碳含量;排烃效率大于阀值时,残余有机碳含量普遍小于原始有机碳含量。在完全排烃条件下,Ⅰ型、Ⅱ1型、Ⅱ2型和Ⅲ型有机质类型泥质烃源岩有机碳含量最大减少幅度大致分别为43%、20%、10%和10%。表5参17更多还原

【Abstract】 According to the mass conservation principle of organic carbon,a mathematical model of organic carbon mass compensation coefficient is established to indicate the variation of organic carbon mass.Considering the influence of organic carbon hydrocarbon generation,hydrocarbon expulsion and rock weight loss,a mathematical model for calculating changes in organic carbon content is also established.Forward method is used to simulate the compensation coefficient of organic carbon mass and the organic carbon content value of source rocks in different evolution stages and hydrocarbon expulsion efficiency.The compensation coefficient variation depends on organic matter type,maturity degree and expulsion efficiency.The maximum compensation coefficients of types Ⅰ,Ⅱ1,Ⅱ2 and Ⅲ organic matter are 2.104,1.360,1.169 and 1.099,respectively.There exists a threshold value in hydrocarbon expulsion efficiency in source rocks,type Ⅰ is 20%,type Ⅱ1 is 30%,type Ⅱ2 and type Ⅲ is 60%.When the expulsion efficiency is less than this threshold value,the residual organic carbon content of the source rock is generally higher than the original organic carbon content;when the expulsion efficiency is greater than the value,the residual organic carbon content is generally lower than the original organic carbon content.Under the conditions of full expulsion,the maximum organic carbon reduction of types Ⅰ,Ⅱ1,Ⅱ2 and Ⅲ muddy source rocks is roughly 43%,20%,10% and 10%.更多还原