The Use of Full-Wave Numerical Simulation for the Investigation of Fractured Zones

Аннотация

In this paper, we describe the stages and results of investigating the features of oil-saturated fractured zones through the analysis of the spatial dynamic wave patterns obtained by supercomputer-aided modeling with the grid-characteristic method. Full-wave modeling is employed in geophysics to construct synthetic seismograms and to solve inverse problems. In this paper, we demonstrate that the analysis of spatial dynamic wave patterns allows us to make conclusions that can later be useful in geophysical surveys. Compared to methods for analysis and interpretation of seismograms, the proposed approach to wave pattern analysis facilitates the investigation of the dynamics of waves of different types, while also being more accurate than the ray-tracing method and geometric approximation. Three types of fractured clusters—solid, intermittent, and chess—are considered. As a result of the investigation, some characteristic regularities are discovered, e.g., the dependence of the seismic wave scattering angle on the source frequency and the geometric arrangement of the fractures in the cluster, and the source frequency dependence of the trajectory and velocity of the point at which the longitudinal head wave separates from the S-wave. These regularities can subsequently be adapted to optimize the seismic prospecting of hydrocarbons and the investigation of fractured zones, e.g., to select the optimal equipment and method for seismic survey. In addition, we discuss the importance of analyzing the spatial dynamic wave patterns when designing and testing numerical methods, as well as interface and boundary conditions, including the absorbing ones. Moreover, we propose an approach to construct a nonlinear scale that enables the simultaneous analysis of the spatial dynamic wave processes whose amplitudes differ by more than two orders of magnitude.