the lower case 201 at its furthest end has two internal cavities 25 and 302 cavity 25 communicates with the exterior by means of small holes 26 the fluid 18 to be recovered from the well bore region may flow through these small holes 26 into the cavity 25 this fluid once it has filled the internal cavity 25 allows to compensate the pressure in the well bore region with that of the device 20 the internal cavity 302 is flooded with a cooling liquid 29 which acts on an expansible set of bellows 27 which in turn allow the expansion of it into the compensation area 28 of the lower case 201 over the compensation chamber 302 there lies a second chamber 301 named u201c stimulation chamber u201d placed in the stimulation zone 34 of the lower case 201 the stimulation zone 34 has holes 35 which allow to increase the level of transmission of acoustic energy to the formation 12 both chambers 301 and 302 in turn form a great chamber 30 that houses the wave guide or sonotrode comprising a radiator 31 said radiator 31 has a tubular geometric shape with an outer diameter d 0 its nearer end having the shape of a horn.