ИСТИНА

This work demonstrates how analysis of elastic wave velocities can help in solving problems related to recognizing oriented fractures. We consider fractures saturated with different fluids at different scales including core, logging, and seismic scales. To solve this problem, we calculate the elastic wave velocities propagating in different directions in fractured anisotropic rocks and then, compare them with the velocities in solid matrix without fractures in order to estimate the fracture effect. For the analysis we use the three most popular methods of Rock Physics – Hudson’s, Eshelby-Cheng’s, and self-consistent scheme. The results obtained with different methods are compared and applicability of each method for calculating the effective properties of fractured rocks is discussed. Specifically, it is shown that the Eshelby-Cheng method cannot be applied for the low-frequency fluid substitution. A possibility to recognize oriented fractures and estimate their orientation using cross-plots of seismic attributes is demonstrated.