The rock cores of low permeability reservoirs have special pore structures, which are the essential factors to determine the seepage capacity and oil displacement efficiency and directly affect oil and gas reserves and oil well productivity. This paper studies 16 digital rock core samples. Based on the fractal theory for porous media, we carried out the fractal characterization of the pore structure of the samples by an approach combined with binarized CT images and fractal theory. The computing software based on the Box-counting method was used to measure and calculate the fractal dimension and porosity of the samples, and the calculated results were compared with the binarized CT data from the laboratory. It was found that among the tested samples, the results of 12 rock core samples were in good agreement with the experimental data, indicating that the fractal theory is effective in the measurement of fractal dimension and in the calculation of porosity of digital rock core samples. For the results with larger errors compared to laboratory data, we also analyzed and elaborated the reasons from the relevant binarized images and pore distribution images of samples. It is also found that the minimum pore size has a significant impact on the results when the fractal theory was applied to analyze the digital rock core samples. Finally, a standard or criterion is established whether the pore/particle size distribution in a digit rock core/porous medium is fractal or non-fractal.

中文翻译：

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数字岩心的分形分析

低渗透油藏岩心具有特殊的孔隙结构，是决定渗流能力和驱油效率的重要因素，直接影响油气储量和油井产能。本文研究了 16 个数字岩心样本。基于多孔介质分形理论，采用二值化CT图像和分形理论相结合的方法，对样品的孔隙结构进行了分形表征。采用基于Box-counting法的计算软件对样品的分形维数和孔隙率进行测量计算，并将计算结果与实验室二值化CT数据进行对比。发现在测试样品中，12个岩心样品的结果与实验数据吻合较好，表明分形理论在分形维数测量和数字岩心样品孔隙度计算中是有效的。对于与实验室数据相比误差较大的结果，我们还从相关的二值化图像和样品孔隙分布图像中分析阐述了原因。还发现，在应用分形理论分析数字岩心样品时，最小孔径对结果有显着影响。最后，建立一个标准或准则，即数字岩芯/多孔介质中的孔隙/粒度分布是分形的还是非分形的。我们还从相关二值化图像和样品孔隙分布图像分析阐述了原因。还发现，在应用分形理论分析数字岩心样品时，最小孔径对结果有显着影响。最后，建立一个标准或准则，即数字岩芯/多孔介质中的孔隙/粒度分布是分形的还是非分形的。我们还从相关二值化图像和样品孔隙分布图像分析阐述了原因。还发现，在应用分形理论分析数字岩心样品时，最小孔径对结果有显着影响。最后，建立一个标准或准则，即数字岩芯/多孔介质中的孔隙/粒度分布是分形的还是非分形的。