Abstract:
A method for spectral analysis of seismic data obtains imaged seismic data and generates orthogonally shifted imaged seismic data gathers. The orthogonally shifted imaged seismic data gathers are processed to generate a spectrally processed imaged seismic data. Alternatively, the imaged seismic data are obtained using a spectral processing filter that is a function of a magnitude of a total wavenumber of the imaged seismic data in three dimensions and a spatially variable velocity function.
Abstract:
A method for seismic exploration using a full waveform inversion, FWI, the method including receiving an initial velocity model V of the subsurface, receiving recorded data d related to the subsurface, generating synthetic data u related to the subsurface, using the initial velocity model V and a source signature of a source S, transforming the recorded data d and the synthetic data u, with a complex wavelet transform, into complex wavelet transformed recorded data d′ and complex wavelet transformed synthetic data u′, respectively, updating the initial velocity model V using the FWI to generate an updated velocity model, based on a cost function J which depends on the complex wavelet transformed recorded data d′ and the complex wavelet transformed synthetic data u′, and generating an image of a surveyed subsurface formation.
Abstract:
A joint timelapse full waveform inversion (FWI) method for estimating physical properties of a subsurface includes receiving seismic data related to the subsurface, wherein the seismic data includes a baseline dataset dB and a monitor dataset dM, defining an objective function of the FWI method, calculating a baseline gradient gB of the objective function for the baseline dataset dB, and a monitor gradient gM of the objective function for the monitor dataset dM, computing a baseline preconditioner P′B for the baseline dataset dB and a monitor preconditioner P′M for the monitor dataset dM so that each of the baseline preconditioner P′B and the monitor preconditioner P′M reflects similarities and/or differences of geometrical features of the baseline and monitor acquisition surveys, and determining physical properties of the subsurface based on a baseline physical properties update and a monitor physical properties update.
Abstract:
A least-square migration, LSM, based method for generating a 4D image of a subsurface, the method including receiving seismic data d related to the subsurface, the seismic data d including a baseline dataset dB and a monitor dataset dM, calculating a baseline filter B and a monitor filter M based on a same common reflectivity r of the subsurface and corresponding remigrated baseline data mB1 and remigrated monitor data mM1 so that the base filter B applied to the remigrated baseline data mB1 equals the monitor filter M applied to the remigrated monitor data mM1, applying the baseline filter B to raw migrated baseline data mB0 and applying the monitor filter M to raw migrated monitor data mM0 to generate LSM baseline data mB and LSM monitor data mM, and generating the 4D image of the subsurface based on the LSM baseline data mB and the LSM monitor data mM.
Abstract:
Methods and apparatuses for seismic data processing perform a least-squares reverse time migration method in which surface-attribute-independent coefficients for the surface attribute gathers are demigrated to reduce the computational cost.
Abstract:
Multi-vintage energy mapping selects a first seismic survey data and a second seismic survey dataset from a plurality of seismic survey datasets. The first seismic survey dataset includes a set of first energies associated with a first seismic survey geometry, and the second seismic survey dataset includes a set of second energies associated with a second seismic survey geometry. The first set of energies are mapped from the first seismic survey geometry to the second seismic survey geometry, and the second set of energies are mapped from the second seismic survey geometry to the first seismic survey geometry. An updated first seismic dataset and an updated second seismic dataset are generated such that only energies from the first and second seismic datasets associated with changes in a subsurface are preserved in the updated first and second seismic datasets.
Abstract:
A non-blended dataset related to a same surveyed area as a blended dataset is used to deblend the blended dataset. The non-blended dataset may be used to calculate a model dataset emulating the blended dataset, or may be transformed in a model domain and used to derive sparseness weights, model domain masking, scaling or shaping functions used to deblend the blended dataset.
Abstract:
Seismic exploration of an underground formation uses seismic excitations to probe the formation's properties such as reflectivity that can be imaged using reverse time migration. Using an equal area spherical binning at reflection points improves and simplifies RTM imaging together with adaptability to the data acquisition geometry, while overcoming drawbacks of conventional cylindrical binning.