Communications: electrical – Wellbore telemetering or control – Using a specific transmission medium
Reexamination Certificate
2005-02-01
2005-02-01
Wong, Albert K. (Department: 2635)
Communications: electrical
Wellbore telemetering or control
Using a specific transmission medium
C702S006000, C367S025000, C367S075000, C181S105000, C181S122000, C181S106000
Reexamination Certificate
active
06850168
ABSTRACT:
The logging tool of this invention includes a transmitter conveyed on a drilling collar for exciting a quadrupole signal in a borehole being drilled by a drill bit and a receiver for receiving the signal. The transmitter is operated at a frequency below the cut-off frequency of the quadrupole collar mode. The received signal consists primarily of the formation quadrupole mode which, at low frequencies, has a velocity that approaches the formation shear velocity. The transmitter, in one embodiment, consists of eight equal sectors of a piezoelectric cylinder mounted on the rim of the drilling collar. The value of the cut-off frequency is primarily dependent on the thickness of the drilling collar. Alternatively, the transmitter may be operated to produce both the collar mode and the formation mode and a processor may be used to filter out the collar mode.
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Dubinksy Vladimir
Leggett, III James V.
Patterson Douglas J.
Tang Xiao Ming
Wang Tsili
Baker Hughes Incorporated
Madan Mossman & Sriram P.C.
Wong Albert K.
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