Anisotropic inversion and imaging of PP and PS reflection data in the North Sea

The technology of ocean-bottom surveys has put mode-converted waves at the forefront of seismic exploration and reservoir characterization. For example, PS-waves proved effective in imaging offshore reservoirs screened by gas clouds that cause high attenuation/scattering of compressional energy (e.g., Thomsen, 1999). Also, information about shear-wave velocities contained in converted modes can be used to separate the effects of saturation and pressure and reduce uncertainty in predicting lithology and fluid saturation. The high sensitivity of PS-wave reflection coefficients to shear-wave velocity and density makes converted-wave AVO analysis potentially powerful for detecting hydrocarbon-saturated rocks.