A method is described for seismic modeling implemented on a computer system including multiple computer nodes, which includes receiving, at a computer processor, a 4D speed of sound in water library and a marine seismic survey geometry; creating, via the computer processor, a full survey 3D Earth model for each seismic shot time based on the 4D speed of sound in water library to generate a set of dynamic 3D Earth models; simulating 4D seismic shots for the set of dynamic 3D Earth models by simulating multiple shots on each node to generate a set of 4D seismic shot gathers; and outputting the 4D seismic shot gathers.

A method and system for estimating a full elastic tensor. The method may comprise taking a measurement for compressional wave sonic data and cross-dipole shear data with a sonic logging tool at a first location as cross-dipole data, processing the compressional wave sonic data to produce a compressional wave slowness (P), and processing the cross-dipole shear data to produce a fast horizontal polarized shear wave slowness (SH) and a slow quazi-vertical shear wave slowness (qSV) as a function of depth. The method may further comprise setting an initial guess for at least five constants of the full elastic tensor for Vertical Transversely Isotropy (VTI) symmetry, determining a modeled slowness surfaces from the full elastic tensor, and comparing the modeled slowness surfaces with measured values of the P, the SH, and the qSV. The method may be performed by a system comprising a sonic logging tool and an information handling system.

Velocity tomography using time lags of wave equation migration is disclosed. Seismic tomography is a technique for imaging the subsurface of the Earth with seismic waves by generated a migration velocity model from a multitude of observations using combinations of source and receiver locations. The migration velocity model may be updated in order to reduce depth differences of reflection events (also called residual depth errors (RDE)). Direct measurement of RDE may be difficult in certain complex subsurface areas. In such areas, the RDE may be reconstructed based on time lags of wave equation migration and then used to update the migration velocity model. In particular, the RDE may be directly reconstructed from the time lags of wave equation migration, such as based on a direct relation between RDE and the time lags.

A method and system for processing a slowness profile. A method may comprise disposing a geophone array into a borehole, positioning the geophone array at a first location within the borehole; discharging a seismic source; positioning the geophone array at a second location within the borehole; discharging the seismic source, wherein the seismic source produces an acoustic wave; recording a vertical seismic profiling dataset, wherein vertical seismic profiling comprises a dataset of recorded acoustic waves by the geophone array at the first location within the borehole and the second location within the borehole; picking a first gap travel time from the vertical seismic profiling dataset; and determining the slowness profile, wherein the slowness profile comprises determining a slowness of the acoustic wave through a formation by the geophone arrays. A well system may comprise a geophone array, comprising a plurality of geophones, and an information handling system.

A method is described for seismic imaging that will produce a seismic image with correctly focused and positioned reflectors. This is accomplished by adding physical geological information to a beam tomography process to generate an updated earth model for the seismic imaging. The method may be executed by a computer system.

The disclosure relates to a method and system for downhole processing of data, such as images, including using a set of downhole sensors to measure parameters relative to the borehole at a plurality of depths and azimuths and detecting predetermined features of the borehole, using a downhole processor, with a trained machine-learning model and extracting characterization data, characterizing the shape and position of the predetermined features that are transmitted to the surface. It also provides a method and system for providing an image of a geological formation at the surface including transmitting a first dataset to the surface that will be used for reconstructing an image at the surface, downhole processing of a second dataset to detect predetermined features and extract characterization data that are transmitted at the surface and displaying a combined image comprising the predetermined features overlaid on the first image.

In one or more embodiments, a system comprises a first (target) wellbore disposed in a formation, the first wellbore having a pressure imbalance therein causing an influx of formation fluids, a second (relief) wellbore disposed in the formation, a drill string disposed in the second wellbore, the drill string comprising a drill bit and a logging tool, and a wellbore ranging module comprising a processor and memory, the wellbore ranging module coupled to the drill string. The logging tool is configured to detect acoustic energy originating from the influx in the first wellbore and generate one or more signals associated with the detected acoustic energy. The wellbore ranging module is configured to receive, from the logging tool, the one or more signals associated with the detected acoustic energy and determine, using the received signals, a direction from the drill bit to the influx of the first wellbore.

A method and system for measuring a compressional and a shear slowness. The method may comprise disposing a downhole tool into a wellbore. The downhole tool may comprise a transmitter, wherein the transmitter is a monopole, and a receiver, wherein the receiver is a monopole receiver. The method may further comprise broadcasting the sonic waveform into the formation penetrated by the wellbore, recording a reflected wave on one or more receivers, wherein the reflected wave is a compressional wave or a shear wave, processing the reflected wave into at least one measurement, and applying a validation scheme to the at least one measurement. The system may be a downhole tool comprising a transmitter configured to transmit a sonic waveform into a formation, wherein the transmitter is a monopole, and a receiver configured to record a reflected wave, wherein the receiver is a monopole receiver.

Methods and systems for identifying a pay zone in a subterranean formation can include: logging a well extending into the subterranean formation including measuring bulk density, compressional wave travel time and shear wave travel time at different depths in the subterranean formation; calculating elastic attributes including acoustic impedance and compressional velocity-shear velocity ratio at different depths in the subterranean formation; and displaying and analyzing the calculated elastic attributes to identify the low resistivity pay zones.

Methods, systems, and computer program products for characterizing materials in a wellbore having multiple casing strings uses well completion data and instantaneous frequency, instantaneous phase, and/or amplitude attributes, including waveform amplitude or instantaneous amplitude, of an acoustic waveform to determine material densities, acoustic velocities and acoustic travel distances for the materials between the various stages of casings.