数字岩心物性数值模拟

针对岩心物性实验周期长且实验结果难以复现等缺点,利用数字岩心对储层岩石物性进行数值模拟。使用计算机断层扫描(CT)技术,获得CT序列图;并由序列图构建三维岩心图像。利用最大内切球方法建立岩心图像的孔隙网络模型,计算岩心渗透性以及岩心中孔喉参数;利用分形维数描述岩心图像的均质性。将数字岩心物性模拟结果和毛管压力曲线数据进行对比,分析了当前物性数值模拟和真实物性实验之间的差距。利用多组岩心样本进行了实验。结果表明,由于成像设备的原因,岩心图像只能表征岩石中的大尺寸孔隙特征;此外,CT图像得到的均质性和物性实验具有很好的一致性,渗透性和物性实验具有一定的出入。

Numerical simulation of digital core physical properties

Aiming at the core petrophysical experiment has shortcomings such as long experiment period and the difficulty to reproduce experimental result, digital core image is utilized to analyze reservoir rock properties. A two-dimensional(2D) image sequence of the core is acquired by using Computed Tomography(CT)technology.The three-dimensional(3D) core image is constructed by the 2D image sequence. Maximum inscribed sphere method is used to establish the pore network model of 3D core image, and calculate the permeability and pore throat parameters. Fractal dimension is utilized to describe the homogeneity of the 3D core image. The results of digital core physical simulation are compared with the data of capillary pressure curve, to analyze the gap between numerical simulation and physical experiment. Experimental results show that mercury injection experiment can measure micro pores, however, due to the imaging equipment, digital core analysis technique can only characterize large size pores. Besides, CT image and physical experiment has a very good consistency about homogeneity, but has a certain discrepancy about permeability.