Abstract: Example methods and systems for wavefield travel-time inversion using eikonal solver are disclosed. One example method includes obtaining multiple first-arrival times of a seismic wavefield measured at multiple receiver locations. Multiple synthetic first-arrival times corresponding to the multiple measured first-arrival times of the seismic wavefield are determined based on an eikonal solver and a near surface velocity model of the seismic wavefield. The near surface velocity model of the seismic wavefield is updated using a wavefield traveltime inversion (WTI) process and based on the multiple synthetic first-arrival times and the multiple measured first-arrival times. The updated near surface velocity model of the seismic wavefield is provided for well location determination.

Abstract: Systems and methods for noise-robust time-domain multi-scale full waveform inversion using convolved data are disclosed. The methods include obtaining, using a seismic acquisition system, an observed seismic dataset pertaining to a subsurface region of interest; obtaining, using a seismic processor, a seismic velocity model; and iteratively, using the seismic processor, until a stopping criterion is met: selecting a wavelet with a frequency parameter, wherein the frequency parameter increases with each iteration, forming a convolved seismic dataset based on a convolution of the wavelet with the observed seismic dataset, and updating, using a full waveform inversion, the seismic velocity model based, at least in part, on the convolved seismic dataset. The methods further include forming a seismic image of the subsurface region of interest using the updated seismic velocity model.

Abstract: Systems and methods are disclosed. The method includes, for each of a plurality of spatial partial differential equations (sPDEs) within a wave equation, determining a linear system of equations using an approximate solution at a plurality of grid nodes. The linear system of equations includes an inverse matrix, a first vector, and a second vector. The method further includes, for each of the plurality of sPDEs, evaluating the inverse matrix by evaluating a first portion of the inverse matrix using a first deconvolution filter and evaluating a second portion of the inverse matrix using a second deconvolution filter. The method further still includes, for each of the plurality of sPDEs, evaluating the first vector using the evaluated inverse matrix and the second vector as well as determining the wavefield using the evaluated first vector for each of the plurality of sPDEs, a velocity model, and the wave equation.