有机质生烃动力学模型对比

摘要

依据23块烃源岩样品生烃热模拟试验数据,建立不同动力学模型(总包反应、正态分布模型、韦布分布模型、离散分布模型)并对模型参数进行优化,对比分析优化效果和不同类型有机质生烃动力学参数特征.结果表明:高斯分布模型拟合效果最差,其次是总包反应模型和韦布分布模型,离散分布模型拟合效果最好;随着指前因子的增加,表观活化能呈增加趋势,且不同类型干酪根的表观活化能按EⅡ2-Ⅲ>EⅠ>EⅡ1的顺序排列;在应用生烃动力学方法评价油气资源量、研究生烃动力学特征以及同位素分馏动力学时推荐采用活化能符合离散分布的平行一级动力学模型.%Different kinetic models including overall reaction model, normal distribution model, Weibull distribution model and discrete distribution model were established, and kinetic parameters were optimized based on systematic research of hydrocarbon generation kinetics experiment for twenty-three source rocks.Then the optimized results and hydrocarbon generation kinetic characteristics of different type kerogen were compared.The results show that Gaussian distribution model has the worst fitting effect, followed by overall reaction model and Weibull distribution model, and the discrete distribution model has the best fitting effect.Apparent activation energy increases gradually with the pre-exponential factors increasing, and the apparent activation energy of type Ⅱ2-Ⅲ kerogen is larger than that of type Ⅰ, and that of type Ⅲ is the smallest.It is recommend the parallel first-order kinetic model with a discrete distribution activation energies be used when the hydrocarbon generation kinetic method is applied to appraise oil-gas resources and to study hydrocarbon generation kinetic characteristics and the isotope fractionation kinetics.