一种考虑成岩作用的砂岩孔隙度解释方法

针对目前利用声波时差建立砂岩孔隙度解释模型存在的问题,对济阳坳陷第三系砂岩储层声波孔隙度关系进行了统计,分析了成岩演化过程及对岩石结构的控制作用.结果表明,砂岩储层的声波孔隙度的关系及变化取决于岩石结构的差异.因而在利用声波时差计算砂岩储层孔隙度时,可采取分不同成岩带建立解释模型的方法.只有在研究完整的成岩演化系统的目标储层时,砂岩骨架时差才对声波孔隙度的关系有意义.在理论分析的基础上,利用声波地层因素方程将不同成岩带的解释模型有机地统一起来.声波地层因素方程是随成岩演化储层结构与孔隙度发生相应变化的综合体现,从而阐述了声波地层因素方程的岩石学成因意义.在应用声波地层因素方程计算孔隙度时,应明确储层所属的不同成岩阶段,这是系统建立声波孔隙度解释模型的理论基础.

An interpretation method for sandstone porosity based on diagenesis effect

A large amount of statistic results of interval transit time and porosity data of sandstone reservoir in the Tertiary of Jiyang Depression showed that the relation between interval transit time and porosity of sandstone was controlled by rock structure,which was affected by diagenesis.An integrated interpretation method for different diagenesis zones was proposed.It was emphasized that the acoustic time of matrix in sandstone would not be significant to relationship between sandstone porosity and interval transit time,until there was a systematical understanding to the diagenesis evolution of target reservoir.The acoustic formation factor (AFF) equation was adopted to integrate all the interpretation models for the different diagenesis zones.The AFF equation can comprehensively reflect the variation of reservoir structure and porosity in the process of diagenesis evolution.When the AFF equation is used to calculate porosity of sandstone,the diagenesis stage of target reservoir should be considered.This is a theoretical basis for establishing the more accurate porosity interpretation model by means of interval transit time.