浅谈储层渗透率变异系数计算方法

Discussion on the variation coefficient calculation method of reservoir permeability

储层的渗透率变异系数、极差、突进系数等是渗透率非均质程度的定量表征。文章探讨了渗透率变异系数的计算方法,认为:变异系数等计算方法与数据分布类型有关,变异系数等参数的计算需根据数据分布特征来选取适合的方法。劳伦兹系数与数据分布类型无关;劳伦兹系数是有界的,分布于0～1之间。尤其是在对数正态分布条件下,劳伦兹曲线、基尼系数完全由标准差σ决定,劳伦兹曲线、基尼系数以及σ这三者间存在着一一对应关系。劳伦兹系数可以用于储层非均质性定量评价。

Variation coefficient, range and dash coefficient of reservoir permeability is the quantitative characterization of heterogeneity of the permeability. This paper discusses the variation coefficient calcula- tion method. The variation coefficient calculation method is related to data distribution type and the prop- er variation coefficient calculation method is selected according to characteristics of data distribution. Lorenz coefficient is independent with data distribution type and is bounded by and distributed in the range of 0 to 1. Especially under condition of logarithmic normal distribution, Lorenz curve and Gini coefficient are completely determined by the standard deviation a. Lorenz curve, Gini coefficient and a have one-to- one correspondence. The Lorenz coefficient can be used in quantitative evaluation of reservoir heterogeneity.