Vibratory source for non-vertical boreholes and method

• US 10,641,913 B2
• Filed: 12/15/2015
• Issued: 05/05/2020
• Est. Priority Date: 03/27/2015
• Status: Active Grant

• Current Assignee: Cgg Services Sas (CGG)
• Original Assignee: Cgg Services Sas (CGG)
• Inventors: Gresillon, Francois-Xavier, Forgues, Eric
• Primary Examiner(s): Phillips, Forrest M
• Application Number:
  US15/552,962
• Publication Number:
  US 20180038972A1
• Time in Patent Office: 1,603 Days
• Field of Search: 181106
• CPC Class Codes: E21B 49/00 Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
• CPC Class Codes: G01V 1/143 using mechanical driving means , e.g. motor driven shaftG01V1/104, G01V1/133 take precedence
• CPC Class Codes: G01V 1/145 by deforming or displacing surfaces , e.g. by mechanically driven vibroseis™
• CPC Class Codes: G01V 1/159 using piezoelectric or magnetostrictive driving means generating mechanical vibrations by using piezoelectric or magnetostrictive effect in general, B06B1/06, B06B1/08
• CPC Class Codes: G01V 1/52 Structural details

Abstract

A reaction mass seismic survey source that is located in an underground casing. The seismic source includes a non-planar base plate; a reaction mass located on the non-planar base plate; and a flextensional element housed in a recess of the reaction mass and configured to vibrate the non-planar base plate when actuated, to generate seismic waves underground.

Claims

1. A reaction mass seismic source configured to advance through and operate in a non-vertical underground casing, the seismic source comprising:

a base plate;

a reaction mass located above the base plate to press the base plate toward a wall of the non-vertical underground casing; and

a flextensional element located between the reaction mass and the base plate and configured to generate seismic waves underground when actuated.

2. The seismic source of claim 1, further comprising:

a guidance piston located between the flextensional element and the base plate.

3. The seismic source of claim 1, wherein the flextensional element comprises:

a piezoelectric element that changes its size when actuated by a voltage; and

an elastic element located around the piezoelectric element and configured to change its shape when the piezoelectric element is actuated.

4. The seismic source of claim 1, further comprising:

support devices located between the reaction mass and the base plate and configured to support a weight of the reaction mass such that the flextensional element is protected from the weight of the reaction mass.

5. The seismic source of claim 1, wherein a weight of the base plate is between 200 and 400 kg.

6. The seismic source of claim 1, wherein the flextensional element includes between one and ten flextensional elements.

7. The seismic source of claim 1, further comprising:

a coupling element configured to be in a retracted state when the seismic source travels through the non-vertical underground casing and to press against the wall of the casing at a location opposite to where the base plate presses the wall when the seismic source is at a shooting location.

8. The seismic source of claim 1, wherein a center of mass of the seismic source is lower than a geometric center so that the base plate remains below the reaction mass when the source travels through the non-vertical underground casing.

9. The seismic source of claim 1, wherein the base plate has end portions along a moving direction to house the reaction mass.

10. A reaction mass seismic source configured to advance through and operate in a non-vertical underground casing, the seismic source comprising:

plural individual source elements connected to each other, each of the source elements comprising;

a base plate;

a reaction mass located above the base plate to press the baseplate toward a wall of the non-vertical underground casing; and

a flextensional element housed in a recess of the reaction mass and configured to vibrate to generate seismic waves when actuated.

11. The seismic source of claim 10, wherein the flextensional element comprises:

a piezoelectric element that changes its size when actuated by a voltage; and

an elastic element located around the piezoelectric element and configured to change its shape when the piezoelectric element is actuated.

12. The seismic source of claim 10, wherein the source element further comprises:

support devices located between the reaction mass and the base plate and configured to support a weight of the reaction mass such that the reaction mass does not touch the base plate.

13. The seismic source of claim 10, wherein flextensional element includes between one and ten flextensional elements.

14. The seismic source of claim 10, wherein the source element further comprises:

a coupling element configured to be in a retracted state when the seismic source element travels through the non-vertical underground casing and to press against the wall of the casing at a location opposite to where the base plate presses with the wall when the seismic source element is at a shooting location.

15. The seismic source of claim 10, wherein a center of mass of each of the seismic source elements is lower than a geometric center so that the base plate is below the reaction mass.

16. The seismic source of claim 10, wherein the base plate has end portions along a moving direction to house the reaction mass.

17. A method for generating seismic waves in a non-vertical borehole, the method comprising:

positioning a source element inside the non-vertical borehole, with a reaction mass of the source element remaining over a base plate thereof;

extending a coupling element to push the base plate against a wall of the borehole;

actuating a flextensional element located in a recess inside the reaction mass, the recess opening toward the base plate; and

generating the seismic waves in the base plate by the actuated flextensional element.

18. The method of claim 17, further comprising:

supporting the reaction mass with a support device so that the reaction mass does not touch the base plate.

19. The method of claim 17, wherein the coupling element is attached to the base plate and extends through the reaction mass.

20. The method of claim 17, further comprising:

retracting the coupling element within the reaction mass; and

moving the source element to a new position within the non-vertical borehole.