Projections: an old diagnostic tool revisited

David C. Henley

Many kinds of projections have been used to help analyze seismic data over the history of seismic exploration, probably the most familiar being the CMP stack. We explore here various projections with an eye to adapting them for particular kinds of analysis. We present, as an example, several different projections applied to a 4D (time-lapse) seismic experiment in central Alberta and discuss the diagnostic possibilities of projections in this setting.

While we draw no conclusions in this work, we review the topic of projections in order to stimulate thinking about new ways in which to summarize and analyze multi-dimensional data volumes. In the figure below, from the time-lapse experiment, only projection (a) is a function of surface location; the other projections are raypath-dependent. In projections (b), (c), and (d), anomalies seem slightly more visible than when they are projected along surface location (better seen at higher magnification).