基于CT扫描与图像处理技术的岩心多尺度裂缝提取方法

Computed tomography and image processing based multi-scale fracture extraction method for core samples

  • 摘要: 裂缝广泛存在于各类岩石中,其特征对于储层评价、油气藏开发和地质灾害预测等领域具有重要意义。现有基于图像处理的裂缝提取技术在微裂缝识别、裂缝细节特征提取、裂缝与孔隙区分等方面存在明显不足。提出了一种多尺度裂缝滤波核叠加降噪方法,采用多个滤波核叠加对岩心CT扫描图像进行滤波降噪,再将滤波结果叠加;提出了一种多尺度信息增强裂缝分割方法,将阈值分割、顶帽分割等图像分割方法与边缘增强技术相结合,以增强微裂缝信息,并针对不同尺度裂缝采取不同的分割策略;分析了图像分割三维体的长度、宽度、表面积、体积、形状因子、平整度和伸长率等形态参数之间的关系。研究结果表明,多尺度裂缝滤波核叠加降噪方法显著降低了岩心CT扫描图像噪声干扰,精准地保留了裂缝细节特征;多尺度信息增强裂缝分割方法提高了多尺度裂缝的提取精确度和稳定性;裂缝形态参数图版能剔除与裂缝相似的孔隙、特殊矿物边界等非裂缝,最终实现多尺度裂缝的准确提取。

     

    Abstract: Fractures are widely present in various kinds of rocks and are critical for reservoir evaluation, deve-lopment, and geological disaster prediction. Existing image-based fracture extraction technologies have noticeable deficiencies in micro-fracture recognition, fracture detail extraction, and fracture and pore differentiation. A multiscale fracture filter kernel superimposition noise reduction method was proposed, which used multiple filter kernels in superimposition to filter and reduce noises in CT scanning images of rock cores, with the filtering results then superimposed. A multiscale information-enhanced fracture segmentation method was also proposed. It combined image segmentation methods such as threshold and top-hat segmentation with edge enhancement to better capture micro-fracture information, applying different strategies for fractures of varying scales. The relationships between morphological parameters such as length, width, surface area, volume, shape factor, flatness, and elongation of the segmented 3D volumes were analyzed. The results showed that the proposed noise reduction method significantly reduced noise interference in CT scanning images of rock cores, and accurately preserved detailed fracture characteristics. This method improves the accuracy and stability of multiscale fracture extraction. The fracture morphological parameter chart effectively eliminates non-fractures such as pores and special mineral boundaries that are similar to fractures, achieving precise extraction of multiscale fractures.

     

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