Seismic vibrator

• US 20090321175A1
• Filed: 06/30/2008
• Published: 12/31/2009
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: PGS Geophysical As (PGS ASA)
• Original Assignee: PGS Geophysical As (PGS ASA)
• Inventors: Tenghamn, Stig Rune Lennart
• Granted Patent: US 7,881,158 B2
• Time in Patent Office: Days
• US Class Current: 181/121
• CPC Class Codes: G01V 1/145 by deforming or displacing surfaces , e.g. by mechanically driven vibroseis™
• CPC Class Codes: G10K 9/121 Flextensional transducers

Abstract

A seismic vibrator includes a transducer, a reactive mass, a base plate to couple motion of the reactive mass to subsurface formations and a linkage system configured to couple motion of the transducer to the reactive mass and the base plate. The linkage system cooperates with the reactive mass and the transducer to define a first resonant frequency and a second resonant frequency within a range of 1 to 300 Hz.

Claims

1. A seismic vibrator comprising:

a substantially elliptically shaped outer spring having a reactive mass coupled thereto;

a transducer having a first end and a second end;

at least one outer driver spring connected between the first end and the second of the transducer;

at least one inner driver spring connected between the first end and the second end of the transducer, the inner driver spring having at least one mass attached thereto;

at least one transmission element connecting the outer spring with the outer spring; and

wherein the springs and the masses in combination determine a first resonance frequency and a second resonance frequency, the first and second resonance frequencies within a frequency range between about 1 Hz and 300 Hz.

2. The apparatus of claim 1 wherein the transducer comprises a magnetostrictive material.

3. The apparatus of claim 2 wherein the magnetostrictive material comprises Terfenol-D.

4. The apparatus of claim 1 wherein the outer driver spring, the transducer and the outer spring together determine a first resonance frequency of the seismic vibrator.

5. The apparatus of claim 4 wherein the inner driver spring, the at least one mass attached thereto and the transducer determine a second resonance frequency of the vibrator.

6. A seismic vibrator, comprising:

a transducer;

a reactive mass;

a base plate to couple motion of the reactive mass to subsurface formations;

a linkage system configured to couple motion of the transducer to the reactive mass and the base plate, the linkage system cooperating with the reactive mass and the transducer to define a first resonant frequency and a second resonant frequency within a range of 1 to 300 Hz.

7. The vibrator of claim 6 wherein the transducer comprises a magnetostrictive material.

8. The vibrator of claim 7 wherein the magnetostrictive material comprises Terfenol-D.

9. The vibrator of claim 6 wherein the transducer comprises a piezoelectric material.

10. The vibrator of claim 6 wherein the linkage system comprises:

a substantially elliptically shaped outer spring having a reactive mass coupled thereto;

at least one outer driver spring connected between a first end and a second end of the transducer;

at least one inner driver spring connected between the first end and the second end of the transducer, the inner driver spring having at least one mass attached thereto; and

at least one transmission element connecting the outer spring with the outer driver spring.

11. A seismic vibrator, comprising:

a transducer;

a reactive mass;

a biasing device;

a base plate to couple motion of the reactive mass to subsurface formations; and

,

at least one transmission element coupling the biasing device to the reactive mass;

wherein the biasing device and the reactive mass in combination determine a first resonance frequency and a second resonance frequency, the first and second resonance frequencies within a frequency range between about 1 Hz and 300 Hz.

12. The vibrator of claim 11 wherein the transducer comprises a magnetostrictive material.

13. The vibrator of claim 12 wherein the magnetostrictive material comprises Terfenol-D.

14. The vibrator of claim 11 wherein the transducer comprises a piezoelectric material.

15. The vibrator of claim 11 wherein the biasing device comprises:

a substantially elliptically shaped outer spring having a reactive mass coupled thereto;

at least one outer driver spring connected between a first end and a end second of the transducer;

at least one inner driver spring connected between the first end and the second end of the transducer, the inner driver spring having at least one mass attached thereto; and

wherein at least one transmission element connects the outer spring with the outer driver spring.