Claims
- 1. A method for generating a seismic signal in a formation traversed by a borehole having borehole fluid therein to obtain information regarding said formation, and utilizing a borehole tool having formation contact means for coupling the borehole tool to the formation, a motor with a rotating drive shaft, a rotor coupled to the drive shaft, a stator which is stationary relative to the rotor, with the rotor and stator arranged to provide substantially sinusoidal signals in the borehold fluid as the rotor turns relative to the stator, a microprocessor means coupled to the motor for causing the motor to turn the rotor, said method comprising:
- a) coupling said borehole tool to the formation utilizing the formation contact means;
- b) controlling said motor with said microprocessor means so as to turn said rotor such that said substantially sinusoidal signals change in frequency in a frequency sweep over a predetermined frequency range;
- c) imparting a force against said formation via said contact means to produce a seismic signal; and
- d) receiving seismic waveform information relating to said seismic signal with at least one geophone located on or near a surface of said formation.
- 2. A method according to claim 1, wherein said formation contact means is a drill bit or at least one stabilizer blade, step (a) comprising:
- causing the drill bit to contact the bottom of the borehole or causing at least one stabilizer blade to contact a side of the borehole.
Parent Case Info
This is a division of application Ser. No. 08/614,288, filed Mar. 12, 1996, now U.S. Pat. No. 5,901,113.
US Referenced Citations (45)
Foreign Referenced Citations (2)
Number |
Date |
Country |
2 251 686 |
Jul 1992 |
GBX |
WO 9307514 |
Apr 1993 |
WOX |
Non-Patent Literature Citations (2)
Entry |
Solstad, Arne, et al. "MPT Pulser as Seismic Isonic Source", EAEG 55th Meeting and Technical Exhibition, Stavanger, Norway, (Jun. 7-11, 1993), Paper C049. |
Hardage, B., Vertical Seismic Profiling, Geophysical Press, 1985, Chapter 1, pp. 1-5. |
Divisions (1)
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Number |
Date |
Country |
Parent |
614288 |
Mar 1996 |
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