变尺度分析方法在水力压裂压力诊断中的应用

The Application of Variable Metric Method in Pressure Distribution Analysis in Hydraulic Fracturing

变尺度分析方法是目前应用最广泛也最成熟的分形统计方法之一,也是一种分析一维分形变量的有效方法。目前,该方法在测井资料分析、裂缝预测和储层评价等方面都有了较为广泛的应用。压裂施工作业时检测到的压力和时间数据也是一一对应的关系,考虑到压裂施工曲线中压力随时间变化的复杂性,把分形几何中的变尺度分析方法引入到水力压裂压力诊断中,结合现场压裂施工实例分憋压造缝、加砂、压降3个阶段进行了分析,旨在探索压裂施工过程中压力随时间变化是否具有分形特性,是否可以形成一种新颖的压力诊断方法。结果表明,该方法切实可行,能够从新的层面对压裂施工曲线进行分析,对压力变化曲线有了新的解读方法,同时对类似井层的压裂施工有重要的指导意义。

Variable metric method is the most widely used and most mature one among the fractal statistical methods, as well as an effective analytical method for analysis of one-dimensional fractal variable. At present, it is widely used in logging, fracture prediction and reservoir evaluation. The pressure and time data measured during fracturing is a one-to one relationship; therefore the rescaled method of fractal geometry analysis is introduced to analyze the pressure data during fracturing. Three stages, ＂holding pressure to create fracture＂, ＂proppant transport＂ and ＂pressure drop＂ are analyzed combined with field application for the purpose of investigating the fractal properties of pressure and looking for a novel pressure diagnosis method. The results show that this method is practicable and can be able to analyze fracturing curve. A new interpretation of hydraulic fracturing pressure was obtained and this method can guide the fracturing operation in similar wells.