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

吴丰 陈学武 赵辉 石祥超 刘建锋

WU Feng CHEN Xuewu ZHAO Hui SHI Xiangchao LIU Jianfeng

西南石油大学 地球科学与技术学院, 成都 610500 中国石油 川庆钻探工程公司 地质勘探开发研究院, 成都 610051 西南石油大学 油气藏地质及开发工程国家重点实验室, 成都 610500 四川大学 水力学与山区河流开发保护国家重点实验室, 成都 610065

School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Research Institute of Geological Exploration and Development, Chuanqing Drilling Engineering Co., LTD., PetroChina, Chengdu, Sichuan 610051, China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China

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。

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.

国家自然科学基金区域创新发展联合基金项目 U20A20266;中国石油—西南石油大学创新联合体科技合作项目 2020CX010303

https://doi.org/10.11781/sysydz2025040882