An introduction to this special section: Advanced borehole seismology

Abstract

A few years ago, a number of major oil companies essentially closed their borehole geophysical research groups; many of us thought this was the death knell for crosswell seismic and reverse vertical seismic profiling. But it turned out to indicate a change in the thrust of the efforts — from major oil‐company‐sponsored efforts to private (consortium‐sponsored) efforts and service companies.