页岩储层矿物组分分形特征研究

Fractal features of mineral component in shale reservoir

页岩储层矿物组分的含量及其分布特征是水力压裂的重要参考因素。以中扬子地区下寒武统水井沱组页岩为例,利用ImageJ软件对页岩CT扫描图像进行处理和分析,研究页岩储层中矿物组分的分布特征,并讨论矿物组分含量和分形维数之间的关系。结果表明:页岩CT图像上矿物组分的密度比有机质和孔隙的密度要大得多,可以根据CT图像的灰度值识别矿物组分。页岩中矿物组分含量越多,矿物组分的分形维数也越大。在矿物组分含量相近的情况下,矿物组分结构越复杂,其分形维数也越大。基于灰度CT图像的页岩矿物组分分形特征研究是页岩储层评价的有效补充,可以更好地指导页岩脆性评价。

The mineral component and its distribution characteristics in shale reservoirs are important factors for hy-draulic fracturing. Taking Shuijingtuo Formation of lower Cambrian in the Middle Yangtze area as an example,we used the ImageJ software to process and analyze the shale CT images,study the distribution characteristics of mineral components in shale reservoirs,and discuss the relationship between the content of mineral composition and fractal dimension. The results showed that the density of the shale mineral component in the CT image is much greater than the organic matter and micro pore structure,so the mineral component can be identified by the gray value of CT image;the more the mineral component content is,the bigger the fractal dimension of the mineral component is in shale. The studies showed that the fractal fea-tures of shale mineral components based on the gray value of CT image is an effective supplement for shale reservoir evalu-ation,and also provides a guide for the shale brittleness evaluation.