渗透率变异系数的几种计算方法——以麻黄山西区块宁东油田2、3井区为例

渗透率变异系数VK反映样品偏离整体平均值的程度,是评价储层宏观非均质性的最重要参数。介绍了三种渗透率变异系数的计算方法：统计学方法、Dykstra H方法和洛伦兹曲线法,并用三种方法分别计算了宁东油田2、3井区的延8和延9层的渗透率变异系数,比较了三种方法的优缺点和适用范围。实践应用表明,洛伦兹曲线法比较适合本地区的研究,因为它所求出的VK值在0和1之间,具有较强的可比性,能很明确的反应各层位非均质性的程度,而且适合任何分布类型的油藏;统计学方法计算的渗透率变异系数在0~∞之间,用这种方法计算的VK很难建立起该油藏非均质程度的概念;Dykstra H方法适用范围很小,仅适应于渗透率接近于呈对数正态分布的油藏,对本区不太适合。

The calculation methods of permeability variation coefficient --taking Ningdong Oilflied in Mahuangshan west block as an example

Permeability variation coefficient VK is the most important parameter to evaluate reservoir heterogeneity. The article describes three calculation methods of permeability variation coefficient such as statistical method, Dykstra H method and Lorenz curve method which are used to calculate permeability variation coefficient of the Y8 and Y9 layers of No. 2 and No. 3 well area in Ningdong Oilflied. The advantages and disadvantages of the three methods and the scope of application are identified. Practice shows that the Lorenz curve method is more suitable for this area, because the value of VK calculated by it is between 0 and 1 which can reflect the degree of heterogeneity clearly, and is applicable for any type of reservoirs.