An effective scheme of joint migration inversion in the pseudo-time domain

Traditional full-waveform inversion is a non-linear and ill-posed inversion problem. To reduce the non-linearity of it, joint migration inversion (joint migration inversion) was proposed as an alternative. Joint migration inversion tries to minimize the mismatch between measured and modelled reflection data. One key feature of joint migration...

Ultrasonic Imaging of the Onset and Growth of Fractures Within Partially Saturated Whitby Mudstone Using Coda Wave Decorrelation Inversion

Using active ultrasonic source survey data, coda wave decorrelation (CWD) time-lapse imaging during the triaxial compression of Whitby Mudstone cores provides a 3-D description of the evolution and redistribution of inelastic strain concentrations. Acoustic emissions (AEs) monitoring is also performed between any two consecutive surveys. From...

Imaging blended vertical seismic profiling data using full-wavefield migration in the common-receiver domain

For vertical-seismic-profiling (VSP) measurements, the use of blended acquisition, with time-overlapping shot records, can greatly reduce the downtime and, thereby, provide large cost savings. For directly imaging blended VSP measurements, we have used full-wavefield migration (FWM). FWM is an inversion-based imaging scheme that enables us to...

Multi-objective full waveform inversion in the absence of low frequencies

Least-squares inversion of seismic reflection waveforms can reconstruct remarkably detailed models of the Earth’s subsurface. However, the cycle-skipping associated with the highfrequency waveforms are responsible for spurious local minima in its objective function. Therefore, it is often difficult for descent methods to converge to the true...

Imaging blended VSP data using full wavefield migration

Blended source and/or simultaneous source acquisition for multi-offset and multi-azimuth VSP measurements can prove significantly beneficial in saving expensive borehole down-time. In the last few years, for the case of surface seismic data, it was proposed to redefine imaging and inversion of the blended data to handle the data directly without...

A new optimization approach for source-encoding full-waveform inversion

Waveform inversion is the method of choice for determining a highly heterogeneous subsurface structure. However, conventional waveform inversion requires that the wavefield for each source is computed separately. This makes it very expensive for realistic 3D seismic surveys. Source-encoding waveform inversion, in which the sources are modeled...