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. (C) 2017 Elsevier B.V. All rights reserved.