变形洛伦兹曲线在识别优势渗流通道方面的应用

Deformed Lorenz Curve for identifying preferential seepage channel

常规吸水剖面洛伦兹曲线可表征油藏纵向整体吸水不均匀程度,但无法对单层吸水能力的变化情况进行刻画。研究提出一种变形吸水剖面洛伦兹曲线。该曲线以注水井吸水剖面数据为素材,将各小层按渗透率值大小进行排序,绘制出注水井吸水量累积百分比与厚度累积百分比的关系曲线。定义变形曲线的斜率值为"优势渗流系数",该系数越大表明曲线段所对应小层的相对吸水能力越强。通过分析曲线,可直观、快速地判断注水井在不同阶段各小层相对吸水能力的变化规律,了解油层纵向上优势渗流通道形成历程,进而识别优势通道发育层位。实践表明,变形曲线实用有效、操作简易,适合在矿场推广应用。

Degree of uneven longitudinal water injection in reservoir can be characterized by Lorenz Curve of conventional water injection profile. But the change in water injection capacity of single layer can not be characterized by the curve. It was proposed a deformed Lorenz Curve of water injection profile,in which layers were ranged by the value of permeability and the relationship curve between cumulative percentage of water injection and thickness cumulative percentage was plotted based on water injection profile data. The slope of the deformed curve was defined as preferential seepage factor. The larger the factor is,the higher the relative water injection capacity of the layer corresponding to the curved section is. The Changing law of water injection capacity for each layer at different stages can be diagnosed directly and quickly by analyzing the curve.And then understanding the longitudinal dominant flow path forming and developing process,the preferential seepage channel was identified in reservoir. The practical application indicated that the deformed curve is effective and easy to use.