A model to relate P‐wave attenuation to fluid flow in fractured tight gas sands

An important issue in reservoir geophysics is to determine whether attenuation/dispersion measurements can be used to predict fluid filled fractures in tight gas sand reservoirs. To address this issue, we assume that fractures in a poroelastic medium can be represented by the permeability, squirt flow and stiffness constants tensors. We also assume that the principal axis of these tensors is aligned with the horizontal x-axis of symmetry. We construct models based on reservoir parameters from the Almond formation of the Siberia Ridge field, Wyoming. We predict attenuation responses by varying the permeability and squirt flow lengths in the plane of the cracks. We also vary the azimuthal and incident angles to predict the appropriate frequency range for detecting fractures. We analyze the sensitivity of the squirt flow length to attenuation and predict the contribution of fracture permeability in low permeability tight gas sands. The modeling results provide inside for detecting fluid filled fractures using acoustic/or seismic measurements in tight gas sand reservoir environments.