CORRELATION A DISTANCE*

The automatic picking of seismic sections becomes delicate with the presence of blind zones breaking up the continuity of horizons. This makes it difficult to establish correlations between reflections coming from above and below these blind zones.

With the help of a certain number of characteristic parameters, a computer capable of storing a great quantity of data makes it possible to identify the horizons bounding a blind zone. Once this investigation has been made, the coherence between these horizons still has to be measured by making a factorial analysis of these different parameters. The statistical decision functions involved in this analysis are well adapted to computer logic. They enable the probability to be given with which the horizons located above and below blind zones correspond.

A program has been worked out to provide the degree of coherence between such horizons.