Seismic Scattering Attributes to Estimate Reservoir Fracture Density: A Numerical Modeling Study

We use a 3-D finite difference numerical model to generate synthetic seismograms from a simple fractured reservoir containing evenly-spaced, discrete, vertical fracture zones. The fracture zones are represented using a single column of anisotropic grid points. In our experiments, we vary the spacing of the fracture zones from 10-meters to 100-meters, corresponding to fracture density values from 0.1- to 0.01-fractures/meter, respectively. The vertical component of velocity is analyzed using integrated amplitude and spectral attributes that focus on time windows around the base reservoir reflection and the scattered wave coda after the base reservoir reflection. Results from a common shot gather show that when the fracture zones are spaced greater than about a quarter wavelength of a P-wave in the reservoir we see 1) significant loss of amplitude and coherence in the base reservoir reflection and 2) a large increase in bulk scattere