A notional source signature of a bubble may be determined. For example, a method for determining a notional source signature of a bubble can include estimating a position of a bubble created by actuation of an impulsive source. A notional source signature of the bubble can be determined based on the estimate.

A system and a computer-implemented include the following. A field dataset of seismic waves is received that is obtained by receivers during a drilling period from a drilling operation at a target well. The drilling period includes drilling and non-drilling phases. The field dataset is analyzed to determine locations of seismic waves. A reconstructed wavefield is determined by applying a passive seismic imaging condition over time and based on locations of the receivers. Using the reconstructed wavefield, a time series is computed for the seismic waves, and a time-frequency transform is applied on the time series. Sources and locations of tube waves resulting from acoustic signatures of the drill bit the drilling phases are determined. Sources and locations of the body waves caused by the tube waves are determined. A petrophysical model of the target well is updated in real-time based on the analyzing and the waves.

A method is described for seismic imaging including receiving a seismic dataset representative of a subsurface volume of interest and an earth model; decomposing the seismic dataset into a set of data sub-sets based on a decomposition function; imaging each data sub-set using the earth model to generate a set of image sub-sets; and combining the set of image sub-sets based on a criterion to create a high resolution seismic image. The method may be executed by a computer system.

Processes and systems are described for generating an image of a subterranean formation from seismic data recorded during a marine survey that employed a moving vibrational source. Processes and systems compute an up-going pressure wavefield from pressure data and vertical velocity data recorded in the marine survey. A direct incident downgoing vertical velocity wavefield that includes Doppler effects created by the moving vibrational source and characterizes a source wavefield and source ghost of the moving vibrational source is computed and deconvolved from the upgoing pressure wavefield to generate a subsurface reflectivity wavefield. The subsurface reflectivity wavefield is effectively free of contamination from the source wavefield, the source ghost, and the Doppler related effects. Processes and systems generate an image of the subterranean formation based on the subsurface reflectivity wavefield, thereby enhancing resolution of the image by attenuating the source-motion effects, source signature, and source ghost of the moving vibration source.

A method is described for modifying an earth model including receiving an earth model containing one or more surfaces with surface geometries, such that at least two surface depth locations exist for some horizontal positions; perturbing elastic properties within the earth model; and generating a modified earth model by modifying the surface geometries within the earth model while preserving seismic travel times of the earth model such that after an initial user parameterization all updates of the surfaces are done without additional user input. The method may be executed by a computer system.

Systems, computer readable, and methods concern receiving seismic data representing a subsurface volume. The method also includes determining, for the seismic data, analysis coordinates as a function of time. One or more of the analysis coordinates may vary in position over time. The method includes performing at least one of an interpolation or regularization process on the seismic data based at least partially on the analysis coordinates. The method also includes outputting a result of the at least one of the interpolation or regularization process.

This invention relates to a method of correcting eccentricity of ultrasonic image profiles, measured along a section of rock, including the steps of measuring emitted amplitude values (A.sub.0) and measuring transit time values (t.sub.) of ultrasonic acoustic pulses emitted at a range of default angles (), where the amplitude measured at each angle (A.sub.) is determined by an amplitude decay model in relation to the transit time (t.sub.) defined by A.sub.=A.sub.0e.sup.t.sup..sup./I.sub. where is the decay correction factor; and I.sub. is the reflection coefficient of the rock wall.

A method is described for seismic imaging including receiving a seismic dataset representative of a subsurface volume of interest and an earth model; decomposing the seismic dataset into a set of data sub-sets based on a decomposition function; imaging each data sub-set using the earth model to generate a set of image sub-sets; and combining the set of image sub-sets based on a criterion to create a high resolution seismic image. The method may be executed by a computer system.

A method of more accurate phase encoding of phase offset vibrators used in simultaneous-multiple-sourcing 3D seismic mapping. The method measures the actual input energy and the proxy energy thereby determining a bulk error and a frequency-dependent error, both to be applied to correct the proxy energy. The corrected proxy energy is then used to perform actual seismic survey, and the inversion is then performed using the corrected proxy energy to source separate each vibe where the error is minimized.

Methods and apparatuses for directional designature in shot domain are provided. Azimuth and take-off angles are calculated for each record in the seismic data. Directional designature is then applied to the seismic data using a source signature dependent on the azimuth and take-off angles.