A method for waveform inversion, the method including receiving observed data d, wherein the observed data d is recorded with sensors and is indicative of a subsurface of the earth; calculating estimated data p, based on a model m of the subsurface; calculating, using a trained neural network, a misfit function J.sub.ML; and calculating an updated model m.sub.t+1 of the subsurface, based on an application of the misfit function J.sub.ML to the observed data d and the estimated data p.

Embodiments provide for a method that utilizes the azimuthally spaced receivers of a sonic logging tool. Signals from monopole and dipole sources are reflected from the geologic interfaces and recorded by arrays of receivers of the same tool. For the incident P-waves from the monopole source, phase arrival times for the azimuthal receivers are compensated for stacking using properties of wave propagation in the borehole, and for the incident SH-waves from the dipole source, signs of waveforms for the receivers are changed for specified azimuths.

Disclosed are methods of marine 3D seismic data acquisition that do not require compensation for winds and currents.

Implementations for monitoring seismic data recorded in a marine survey of a subterranean formation for coverage gaps are described herein. Implementations include computing Fresnel sum operators for Fresnel zones of the subterranean formation based on a Kirchhoff migration impulse response at horizons of a representative plane layer model of a survey area of the subterranean formation. Implementations also include computing an acceptability map of the survey area based on the Fresnel sum operators. The acceptability map reveals coverage gaps in the survey area. Geoscientist may use the acceptability map to infill seismic data in areas of the survey area that correspond to the coverage gaps.

A method may include obtaining a P-wave velocity model and velocity ratio data regarding a geological region of interest. The method may further include generating, based on the P-wave velocity model and the velocity ratio data, an initial S-wave velocity model regarding the geological region of interest. The method may further include determining various velocity boundaries within the initial S-wave velocity model using a trained model. The method may further include updating the initial S-wave velocity model using the velocity boundaries, an automatically-selected cross-correlation lag value based on various seismic migration gathers, and a migration-velocity analysis to produce an updated S-wave velocity model. The method further includes generating a combined velocity model for the geological region of interest using the updated S-wave velocity model and the P-wave velocity model.

A computer-implemented method may include obtaining seismic data acquired in a time-domain for a subterranean region of interest. The method may further include obtaining a property model for the subterranean region of interest. The method may further include determining one or more time shifts using a segment dynamic image warping function based on the seismic data and the property model. The method may further include determining an adjoint source operator using the derived time shift and one-way wave equation. The method may further include updating the property model using a gradient solver in a data-domain reflection traveltime inversion. The method may further include outputting the updated property model for the subterranean region of interest. The method may further include generating a seismic image for the subterranean region of interest using the updated property model.

A method and system for locating a reflector in a formation. The method may comprise broadcasting a sonic waveform as a shear formation body wave or a compressional formation body wave into the formation, recording a reflected wave from a reflector with the one or more receivers as dipole data by the dipole receiver and quadrupole data by the quadrupole receiver, and processing the dipole data and the quadrupole data with an information handling system to determine a location of the reflector from the borehole sonic logging tool. The system may comprise a borehole sonic logging tool and an information handling system. The borehole sonic logging tool may comprise one or more transmitters configured to transmit a sonic waveform into a formation and one or more receivers configured to record a reflected wave as a dipole receiver for dipole data and a quadrupole receiver for quadrupole data.

Reducing migration distortions in migrated images of the Earth's subsurface. Recorded seismic data may be migrated, using a migration velocity model, to generate a migration image comprising ADCIGs with distortions. Synthetic seismic data may be generated, using the migration velocity model, for a grid of point scatterers. The synthetic seismic data may be migrated, using the migration velocity model, to generate impulse responses for the point scatterers. The impulse responses are used as point spread functions (PSFs) which approximate the blurring operator, e.g., the Hessian. An optimal reflectivity model may be selected using image-domain least-squares migration (LSM), based on the PSFs, with regularization of the difference between the migration image and a reflectivity model and a total variation (TV) regularization of the reflectivity model in the spatial and angular domains. An image of the optimal reflectivity model may be generated with reduced migration distortions compared to the original migration image.

A method for seismic processing includes steps of seismic signal forward propagation and seismic data back propagation. The subsurface medium image is created after correlating and summarizing forward and backward propagation results. To address migration footprint and noise due to the incomplete data acquisition aperture and migration approximation in the migration operator, the iteration inversion strategy incorporates tensor flow calculated from seismic image. A regularization operator based on structure tensor of image is applied to seismic image inversion.

The present disclosure belongs to the technical field of seismic exploration imaging, and relates to an interpretive-guided velocity modeling seismic imaging method and system, a medium and a device. The method comprises the following steps: S1. performing first imaging on a given initial velocity model to obtain a first imaging result; S2. performing relative wave impedance inversion on the first imaging result to obtain a relative wave impedance profile; S3. performing Curvelet filtering on the relative wave impedance profile to obtain a first interpretation scheme; S4. superposing the first interpretation scheme and the initial velocity model to obtain a new migration velocity field; S5. performing second imaging on a new migration velocity field to obtain a second imaging result; and S6. repeating steps S2-S4 for the obtained second imaging result until a final seismic imaging result is obtained.