开放体系下干酪根生烃动力学研究

KINETICS STUDY ON HYDROCARBON GENERATION OF KEROGEN IN OPEN-SYSTEM

以生烃动力学方法对烃源岩进行定量评价是近些年发展起来的一种新方法。通过对Ⅰ、Ⅱ型干酪根在开放体系下的热解模拟实验,研究了Ⅰ、Ⅱ型干酪根热解生烃演化特征,获得了Ⅰ、Ⅱ型干酪根的生烃动力学参数。Ⅰ型干酪根生烃的活化能分布范围为230～276kJ.mol-1;Ⅱ型干酪根活化能分布范围为234～276kJ.mol-1。在此基础上,结合专用Kinetics软件,将此动力学参数应用于实际地质中。结果表明,Ⅰ型干酪根主要生烃期在130～180℃(Ro在0.80%～1.63%);Ⅱ型干酪根主生烃期在141～177℃(Ro在0.92%～1.56%)。生烃动力学方法可较好地将实验数据外推到地质实际过程,在烃源岩评价与勘探中具有广泛的应用价值。

Qualitatively evaluating hydrocarbon source rocks by means of hydrocarbon generation dynamics is the latest way developed in recent years.A new method for the quantitative assessment of source rocks by means of the chemical reaction Kinetics is developed gradually over the recent years.In this paper,the characteristics of hydrocarbon generation of KerogenⅠandⅡare studied,and the kinetics parameters of hydrocarbon generation are determined and calibrated in open-system with thermal simulating experiment.The activate energy values of KerogenⅠandⅡrange from 230 to 276kJ·mol-1 and from 234 to 276kJ·mol-1 respectively.The kinetics parameters then are extrapolated to geological condition by using the special kinetics software.The result shows that the main hydrocarbon-generation periods for Kerogen I is from 130℃ to 180℃(Ro between 0.80% and 1.63%),while the main hydrocarbon-generation periods are from 141℃ to 177℃(Ro between 0.92% and 1.56%)for KerogenⅡ.Kinetics of hydrocarbon generation can make experimental data better extrapolate to geological process,thus there is broad prospective in assessment and exploration of source rock.