Method and device for emitting radial seismic waves in a material medium by electromagnetic induction

摘要

Method and device for emitting radial seismic waves in a material medium by electromagnetic induction, used notably for generating seismic waves in cased or uncased wells or in a water mass. Emission of radial waves is essentially obtained by radially expanding a metal tube (1) under the effect of a magnetic pressure generated by electromagnetic induction, elastic waves being created in the medium under the effect of this expansion. The magnetic pressure is obtained by connecting a coil (2) in line with the tube to a current generator (3): shock generator, variable-frequency generator. The winding pitch of coil (2) can be constant or variable. Tube (1) can for example be added into a well or hole or it can be a tube portion of a cased well. It can also be the lateral wall of a sealed enclosure that is immersed in a water mass so as to produce acoustic or seismic waves therein. Applications: seismic prospecting or monitoring of the subsoil for example.