Characterizing Fault Damage Zones Using Forward Modeling Within Superdeep Carbonates in Northwest China

By using forward modeling and associated seismic attributes of variance, four fault models of idealized damage-zones are characterized, and the frequency effect is evaluated on the width estimation of fault damage-zones in the subsurface. Main results indicate: (1) The general geometrical pattern of damage-zones could be identified by using simulated amplitude and seismic variance with main frequencies of 10, 25, and 40 Hz; (2) The estimated widths of damage-zones at a low frequency of 10 Hz are larger (up to two-fold) than those at frequencies of 25 and 40 Hz; For large damage-zones (>400 m), the width is best estimated by a frequency of 25 Hz; (3) Scattering noise and diffraction around the fault are found in data at a high frequency of 40 Hz, which results in width overestimation of the damage-zones by ~17%. The internal structures are difficult to distinguish as scattering noise and chaotic reflections dominate seismic signals. More factors that may influence the accuracy of damage-zone width estimation via seismic attributes, include the bedding thickness, fracture density, and velocity.