True-Amplitude Pseudoacoustic-Wave Gaussian-Beam Migration in VTI Media with Ocean-Bottom 4C Seismic Data

Summary Ocean-bottom node (OBN) surveys use sensors on the seafloor to collect seismic data with four components (4C). Current imaging methods for 4C data, consisting of both displacement and pressure measurements, either assume that the subsurface medium is isotropic or can only provide imaging results for a single physical quantity (such as velocity, reflection coefficient, or scattering potential) while taking into account anisotropy. These methods cannot simultaneously image geometric structures and accurately recover medium properties in the presence of anisotropy. To solve this problem, in this paper, we present a new method to image anisotropic ocean-bottom 4C data using the qP-wave VTI scattering pattern matrix. Our method combines Gaussian-beam qP-wave true-amplitude migration with multiparameter inversion in VTI media. The recovered parameters include perturbations of the NMO velocity parameter, the anelliptic parameter $\eta$, and Thomsen’s parameter $\delta$. Additionally, the method performs deghosting and qP-wave separation during migration. We showcase the effectiveness of our approach using a synthetic data set for the Gullfaks model in the North Sea, demonstrating its capability to produce clear qP-wave images from 4C data in a weakly anisotropic medium.