3D imaging of fractures in carbonate rocks using X-ray computed tomography technology

摘要

A number of techniques have been developed to detect and study fractures growth in rocks in the past few decades. Among them, the high-resolution X-ray computed tomography (CT) is a useful, rapid and nondestructive way to test and visualize the interiors of rocks in two and three dimensions. The difference in X-ray absorption between the mineral grains and the fractures can create well-contrasted CT images. In this paper, the main objective is to image the fractures in carbonated rock under uniaxial compression and rock fracturing experiments using the CT imaging technique in three dimensions. In the uniaxial compression test, the CT technology is performed to observe the macroscopic fractures in rock after failure. The 3D tomograms indicate that microcracks in rock mutually interconnect and eventually form macroscopic fractures. Then, the rock fracturing experiment is conducted to observe the geometry of induced fractures with the aid of the CT imaging. The 3D tomograms and visualized images show that the induced fracture intersects with the surface of rock sample, indicating that the CT technology can depict the induced fracture accurately. Moreover, the 3D visualized images illustrate that the macroscopic induced fracture in rock is produced with well-developed roughness. The experimental results show that the CT technique is a useful way to observe the fractures in rocks.