BOREHOLE DIGITAL GEOPHONE TOOL

摘要

A method and apparatus for acquiring acoustical data from a borehole and is especially useful in carrying out tomogrphy surveys. The borehole digital geophone (BDG) tool of the present invention is capable of operating from a standard, 7-conductor logging cable with no special cables being required since the individual digital geophone modules (DGM) which form the BDG tool are connected together by short, separate lengths of the same 7-conductor cable. Each DGM acquires, digitizes, stacks, and stores data generated by its own three-component geophone assembly prior to transmitting these signals to the surface over a dedicated conductor in the cable thereby substantially increasing the sample rate of the tool which, in turn, substantially reduces the field time to run a tomography survey.