生烃潜力法在排烃研究中应注意的几个问题

SOME PROBLEMS ABOUT IMPLICATION OF HYDROCARBON-GENERATION POTENTIAL METHOD ON RESEARCH THE EXPULSION CHARACTERISTICS OF SOURCE ROCKS

讨论了生烃潜力法在研究源岩排烃特征中容易被忽视的几个关键问题。这些问题表现在:第一,源岩中有机质分布具有非均质性,因此需要用同一深度段内生烃潜力指数的平均值来代替该深度的生烃潜力指数;第二,对于存在剥蚀历史的盆地,在建立排烃模式之前要先将剥蚀区采样点的数据进行"深度归位";第三,剥蚀区烃源岩排烃历史过程中其排烃率在抬升剥蚀阶段不是减小的,而是保持不变,需要对其进行校正;第四,在对剥蚀区有效源岩厚度进行统计之前,首先要对该地区的剥蚀厚度进行恢复,然后再进行有效源岩厚度统计。

Based on material balance principle and hydrocarbon expulsion threshold theory,the hydrocarbon expulsion characteristics and history can be studied exactly by using the hydrocarbon-generation potential method.The problems are discussed which can be easily neglected during the process of study by introducing the calculation principle and steps of hydrocarbon-generated potential method.The problems are that firstly,due to the heterogeneous distribution of kerogen in source rocks,an average value of hydrocarbon-generated index is used to stand for hydrocarbon-generation index in the corresponding depth,secondly,the data should be 'Depth homing' before setting up the hydrocarbon expulsion model in a erosion area,thirdly,hydrocarbon expulsion rate of source rocks is kept as a constant value during erosion stage,which needs to be rectified,and lastly,the erosion thickness should be studied before calculating the effective thickness of source rocks.