High-Resolution Seismic Imaging for Fracture Detection. Past advances in seismic imaging that use surface methods can identify anisotropy, which can be caused by the geologic fabric, as well as fractures. Therefore, an approach is needed to sort out the different effects to identify the fractures controlling fluid flow. In the mixing model, attenuation and velocity depend upon the resonance frequency of gas bubbles in fluid. The mixing model explains the large amplitude drop and small velocity change within fractures.
Seismic resolution depends upon velocity inside of the fracture.
This approach can be used to compute fracture aperture profiles. Compared to examining paper data plots, computerbased seismic analysis software systems allow rapid viewing of seismic lines in a wide variety of versions. Plots flattened on a particular reflection are often useful to show slight thickening of the upper Knox, thinning above a remnant, or to highlight the structural history. On the re-examined old lines, numerous undrilled marginal prospects were identified, including small structures. There also was evidence of a rise of the unconformity level and a small amplitude anomaly.