基于叠后地震资料方位振幅变化率差异的裂缝预测技术

    A fracture prediction technique based on differences in azimuthal amplitude variations in post-stack seismic data

    • 摘要: 裂缝作为油气储层的重要渗透通道与储集空间,其分布特征(密度、方向)的精准预测对油气勘探开发具有关键意义。现有叠后裂缝预测方法(如相干、曲率等)因无法有效提取方位差异信息,难以满足精细化研究需求。本文提出一种基于叠后地震方位属性差异椭圆拟合的裂缝预测方法:通过构造导向滤波优化原始数据,选取3个及以上特征方位角提取方位属性,利用椭圆拟合、量化属性的各向异性,最终通过椭圆参数(扁率、长轴/短轴方向)反演裂缝密度与方向。某油田实际数据应用结果表明,该方法预测的裂缝密度、方向与钻井实钻结果吻合度高,显著优于传统叠后方法,为缺乏宽方位叠前数据的工区提供了高精度裂缝预测的解决方案。

       

      Abstract: Fractures serve as important seepage channels and storage spaces for hydrocarbon reservoirs. Therefore, the precise prediction of their distribution characteristics (density and orientation) holds critical significance for hydrocarbon exploration and development. However, existing fracture prediction methods using post-stack seismic data (such as coherence and curvature) cannot effectively extract azimuthal differences, thus failing to meet the demand for high-precision fracture prediction. Given this, this paper proposed a fracture prediction method by performing ellipse fitting on azimuthal attribute differences of post-stack seismic data. Specifically, the original data were optimized using structure-oriented filtering, from which three or more characteristic azimuth angles were further selected to extract azimuthal attributes. Then, the extracted attributes were analyzed using ellipse fitting to quantify attribute anisotropy. Ultimately, the fracture density and orientation were inverted using ellipse parameters (the ellipticity and major/minor axis directions). The practical application of this method in an oil field demonstrates a high coincidence between the predicted fracture density and direction and the actual drilling data, achieving superior accuracy compared to conventional fracture prediction methods. This method provides a high-precision fracture prediction solution for areas lacking wide-azimuth pre-stack seismic data.

       

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