Time-lapse seismic data are widely used for monitoring timevariant subsurface changes. Conventional analysis provides qualitative information by comparing results from consecutive surveys, whereas waveform inversion can retrieve quantitative estimates of reservoir properties through seismic waveform fitting. The quantitative evaluation of the physical parameters obtained by waveform inversion a...

Time-lapse (4D) seismic data sets have proven to be extremely useful for reservoir monitoring. Seismic-derived impedance estimates are commonly used as a 4D attribute to constrain updates to reservoir fluid flow models. However, 4D seismic estimates of P-wave impedance can contain significant errors associated with the effects of seismic noise and the inherent instability of inverse methods. Th...

We collected SH-wave seismic reflection data over a shallow aquifer in southwestern British Columbia to investigate the use of such data in hydrogeologic applications. We used this data set in developing a methodology that uses cone penetrometer data as an integral part of the inversion and interpretation of the seismic data. A Bayesian inversion technique converts the seismic amplitude variati...

An ever present goal of seismic processing and inversion is to extract meaningful geology information from seismic data. The simplest possibility is to invert for seismic impedances, or, considering density constant, invert for velocities. Here I use a micro genetic algorithm program to achieve this goal. I use a real sonic log to compute a synthetic seismic trace and then use that trace as inp...

Wave-equation, finite-frequency imaging and inversion still faces considerable challenges in addressing the inversion of highly complex velocity models as well as in dealing with nonlinear imaging (e.g., migration of multiples, amplitudepreserving migration). Extended images (EI’s), as we present here, are particularly important for designing image-domain objective functions aimed at addressing...

In this tutorial, I present an overview of the techniques that are in use for prestack seismic amplitude analysis, current and historical. I show that these techniques can be classified as being based on the computation and analysis of either some type of seismic reflection coefficient series or seismic impedance. Those techniques that are based on the seismic reflection coefficient series, or ...

Seismic waveform inversion aims at obtaining detailed estimates of subsurface medium parameters, such as the spatial distribution of soundspeed, from multi-experiment seismic data. A formulation of this inverse problem in the frequency-domain leads to an optimization problem constrained by a Helmholtz equation with many right-hand-sides. Application of this technique to industry-scale problem f...

Identifying facies for classification for a seismic inversion project is an important step where one balances computational effort and the quality of the results. We propose a new measure to quantify the suitability of a given facies partition based on information theory. The results depend on a user-selected cutoff, and we propose a reasonable value for this constant. We also show the analysis...

Velocity model estimation from seismic data using prestack depth migration is an un-derdetermined problem: there are many subtly diierent models which are not kinematically equivalent. As these models can give rise to dramatically diierent interpretations and decisions there is a clear need for a selection criterion in order to choose the "best" (i.e. geologically most plausible) one. Interpret...

Accurate earthquake source parameters such as fault mechanism, depth, and moment magnitude are not only important in seismic-hazard assessment, but also are crucial to studies of earthquake rupture processes and seismotectonics. Although large earthquakes (Mw 7+) may cause substantial damage, they occur less frequently. In contrast, moderate earthquakes (Mw 5.0–6.5) occur with much higher frequ...