A novel approach of two-dimensional representation of rock fracture network characterization and connectivity analysis

The weak structural planes, such as joints and fractures, are the basic structural features of formation. The effective communication of the fracture network can increase the stimulated reservoir volume. It is necessary to identify and describe the fractures network characterization effectively for improving oil and gas recovery. A numerical approach is presented in this paper to describe the connectivity of natural fracture networks and analyze the two-dimensional geometric features accurately. Based on the theory of the fractal and topological geometry, a fractal description model of the fracture size and fracture number were established. Furthermore, the two-dimensional simulation of the fracture network connectivity is carried out, and the effects of fractal dimension, the number of fracture groups and the angle of fracture group of the network connectivity are also analyzed. From the results, the three conclusions can be drawn. First, the fracture connectivity is sensitive to the fractal dimension, the number of fracture groups and the angle of the fracture group. Second, with the increase of the fractal dimension, the fracture connectivity becomes worse. And with the increase of the number of fracture groups and the angle between fracture groups, the fracture connectivity become better. Third, The threshold of fracture connectivity is controlled by the fractal dimension, the initial quantity and the initial fracture length. From all above, this study provides a numerical approach and theoretical support for the distribution of rock fracture reservoir.