Patent ID: 7463551

Claim:
A method of using an acoustic logging tool conveyed in a borehole in an earth formation on a bottom hole assembly (BHA) for determining a characteristic of the formation, the BHA including a conduit for conveying a drilling fluid from a surface location to a drillbit on the bottom hole assembly, the method comprising: (a) using a primary acoustic source in said BHA for; (I) generating an acoustic signal in a fluid flow path selected from (i) said conduit, and (ii) an annulus between said BHA and said earth formation; and (II) radiating a first acoustic signal into the earth formation; (b) using a secondary acoustic source for producing a radiated second acoustic signal into the earth formation in response to the acoustic signal in the fluid flow path; and (c) recording a signal produced by interaction of said radiated first signal and the radiated second signal with said earth formation.