NEW APPROACH TO DRILL-STRING ACOUSTIC TELEMETRY.

A new approach to acoustic communication along the drill string employing zero-order torsional acoustic waves is presented. This new approach is introduced because the extensional acoustic waves presently used by the petroleum industry in drill string acoustic telemetry are fundamentally limited to short communication distances along the string, except for extremely low data rates. Two new types of drill string acoustic communication system that are made feasible by the low attenuation of zero-order torsional waves are cited.