数字岩心建模方法研究现状及展望

Review of digital core modeling methods

数字岩心是进行岩石物理数值模拟实验的重要平台,可以广泛地应用于固体力学、声学、电学、流体力学及流固耦合等数值模拟实验,但进行各种数值模拟实验的前提是要建立一个准确的三维数字岩心模型.通过系统调研国内外数字岩心建模方法,将数字岩心建模方法划分为三大类:物理实验法、数值重建法和混合法.在简要介绍不同建模方法的基本原理和优缺点的基础上,对今后建模方法的发展进行了展望.研究结果表明:序列切片成像法与聚焦离子束等技术相结合将会是研究致密岩石孔喉结构特征的重要手段;X射线CT扫描法具有快速、精确、无损的优点,它会是最主要的建模方法,更适用于常规和低渗透岩心.随机模拟法具有成本低效率高的优势,在所建模型准确性较高的前提下,它将是重要的建模方法;过程法模拟了沉积岩石的形成过程,具有独特的建模优势,适用于成岩作用简单的岩石;混合法结合多种建模方法的优点,是建立双孔隙网络或含裂缝等复杂数字岩心模型的最佳选择.

Digital core model is an important platform for simulating rock petrophysics experiments, which can be widely used for studying various petrophysics properties and transport processes,such as solid mechanics,transport of acoustics,electricity and fluid and fluid-solid coupling. However,the premise of carrying out all the numerical simulation experiments is constructing an accurate 3 D digital rock model. To date the methods of reconstructing digital core models can be divided into three groups： physical experiment method, numerical reconstruction method and hybrid method through systematic investigation in digital core modeling methods at home and abroad. Based on the brief introduction of the core principles and the discussion of advantages and disadvantages of each method,the future development of modeling methods is given.The research results show,the technique of combining the serial sections tomography method and focused ion beam technology will be a significant method for studying the characteristics of pore throat structures for tight rocks. X-ray Computer Tomography Scanning method has the merits of accuracy and non-destruction,so it will be the most vital method among these techniques of building digital rock models and is suitable for conventional and low-permeability rocks. The stochastic simulation method has the advantages of low cost and high efficiency,and it will be an essential method as long as the high accuracy of the reconstructed models is ensured. The process-based method simulates the formation process of sedimentary rocks, and has the unique advantages compared with other stochastic methods, and it is suitable for rocks that underwent simple diageneses. The hybrid method combines the advantages of multiple methods,which is the best choice for establishing complex digital core models which contain dual pore networks or fractures.