Patent ID: 6915875
Filing Date: 2005-07-12
Classification: G01V

Abstract:
1. An apparatus for performing acoustic investigations while drilling a borehole subsurface geological formation, comprising: (a) a longitudinally extending body conveyed in said borehole on a drilling tubular, said body and said drilling tubular having a drilling fluid flowing therethrough; (b) an acoustic transmitter supported by the body, said transmitter generating acoustic signals in the body, the borehole and the subsurface formation; (c) an acoustic receiver spaced apart from the transmitter and supported by the body for receiving said acoustic signals; and (d) an attenuator located on a substantially cylindrical portion of the body between said acoustic transmitter and said acoustic receiver for attenuating said acoustic signals in the body within a predetermined frequency range; wherein said attenuator comprises a plurality of spaced-apart masses having a predetermined spacing, mass and length firmly attached to an external surface of an outer wall of the cylindrical portion of the body.