A method for estimating sonic slowness comprising: obtaining (700) a plurality of sonic waveforms are received by a plurality of receivers of a logging tool after emission of a source sonic wave by a transmitter, obtaining (710) slowness models of the subterranean formation, a slowness model being defined by a at least one cell of constant slowness for at least one wave energy mode, computing (720), for each slowness model, a set of candidate travel times, a candidate travel time of a set of candidate travel times being computed for a wave energy mode and a position of a receiver of the plurality of receivers, computing (730) a relevance indicator for each set of candidate travel times based on the recorded sonic waveforms; searching (740) a match between the sets of candidate travel times and the recorded sonic waveforms by searching a relevance indicator which is optimum, computing (750) a sonic slowness estimate for the subterranean formation from a set of candidate travel times for which the relevance indicator is optimum.

A method to measure borehole Stoneley wave slowness and its associated tool-corrected dispersion curve. The method for measuring borehole Stoneley wave slowness may comprise gathering waveforms, conditioning waveforms, identifying slowness constraints, computing a time-slowness mask, computing a coherence map from differential phase time semblance, processing a two-dimensional time-slowness map, determining slownesses from a one-dimensional variable density log, and tracking time pick from a two-dimensional map. The method may further comprise identifying one or more of coherence, power, instantaneous frequency, signal-to-noise ratio, or error bars from the two-dimensional time-slowness map. The method may further computing a spline interpolation locally around the pick from the one-dimensional variable density log to produce a final data product.

A method is described for full waveform inversion using a b-spline projection that produces an earth model that can be used for seismic imaging. The method may be executed by a computer system.

A method is described for image-domain full waveform inversion. The method may include receiving, at a computer processor, a seismic dataset representative of the subsurface volume of interest and an initial earth model; performing, via the computer processor, an image domain full waveform inversion to generate an updated earth model; and performing, via the computer processor, seismic imaging of the seismic dataset using the updated earth model to generate a seismic image. The method may be executed by a computer system.

A method for seismic data processing can include obtaining seismic data acquired based upon trigger times and not based upon positions of triggered source elements. The seismic data can include near-continuously recorded seismic data in split records. The split records can be spliced together into a single near-continuous record to produce a trace with seismic data from a single acquired line. The seismic data can be processed by performing a spatial shift for each of a number of time samples to correct for motion of a number of seismic receivers.

Method for simultaneously inverting full-wavefield seismic data (51) for multiple classes of physical property parameters (e.g., velocity and anisotropy) by computing the gradient (53), i.e. search direction (54), of an objective function for each class of parameters, then applying (preferably exhaustive) first-pass independent line searches to each parameter class to obtain the corresponding step size (55) along the search direction for each parameter class; then without yet updating the model, using the step sizes to define a relative scaling between gradients of all parameter classes. Next, each scaled search direction is recombined to form a new search direction (56), and a new second-pass line search is performed along the new search direction (57), and all parameters are simultaneously updated with the resulting step size (58). Alternatively to the preceding alternating two-pass embodiment, the model may be updated after each first-pass line search, and no second-pass line search is performed.

A method for seismic data acquisition can include near-continuously recording seismic data received from a number of seismic receivers and triggering a plurality of source elements, based upon time and not based upon position, at a predefined sequence of times relative to a start of a near-continuous recording.

Marine survey data resulting from a first signal comprising a signal representing a flat spectral far-field pressure generated by a marine vibrator source swept over a frequency range according to a time function of motion such that acceleration of the marine vibrator source is a flat function in a frequency domain can be used to improve full waveform inversion. For example, full waveform inversion can be performed using the marine survey data received from the first signal and from a second signal generated by an impulsive seismic source to estimate a physical property of a subsurface location.

A method for seismic data processing can include obtaining seismic data acquired based upon trigger times and not based upon positions of triggered source elements. The seismic data can include near-continuously recorded seismic data in split records. The split records can be spliced together into a single near-continuous record to produce a trace with seismic data from a single acquired line. The seismic data can be processed by performing a spatial shift for each of a number of time samples to correct for motion of a number of seismic receivers.

A method and system for determining an azimuth of a marsquake/moonquake event. The method includes: filtering the original waveform data to obtain filtered waveform data; intercepting filtered waveform data of a set time length to obtain first arrival waveform data of a P wave; performing data analysis on the first arrival waveform data of the P wave, determining the first arrival waveform data of the P wave of an east component as X-column data and the first arrival waveform data of the P wave of a north component as Y-column data; and performing optimal fitting on the X-column data and the Y-column data to obtain a first arrival elliptical locus of the P wave obtained after the optimal fitting, and determining an azimuth of a marsquake/moonquake relative to the single seismic station according to the first arrival elliptical locus of the P wave obtained after the optimal fitting.