Attenuated traveltime tomography method for estimation of seismic attenuation

Due to the viscous-elastic properties of subsurface media, seismic waves experience a loss of amplitude and distortion of phase during propagation. Compared with frequency domain methods, tomography methods are designed to calculate a set of Q values simultaneously. But we have noticed that most existing tomography inversion methods may result in inaccurate Q estimation because of many adverse factors. In addition, these methods can only calculate effective Q between layers. Improved attenuated traveltime (t⁎) tomography is introduced here as a more accurate and efficient method for estimation of true Q distribution, instead of effective Q values. The method updates an initial Q guess to the true Q distribution through inversion. The accuracy of t⁎ is essential for t⁎ tomography. Minute errors of t⁎ can cause unreasonable Q inversion results. A stabilized method is designed to improve the accuracy of t⁎ by statistically selecting the optimum frequency band for regression. Synthetic and field data examples demonstrate the feasibility and effectiveness of this method. Depending on the more accurate Q distribution, seismic resolution can be improved after Q compensation migration.