Double-Acting Shock Damper for a Downhole Assembly

• US 20130168092A1
• Filed: 01/04/2012
• Published: 07/04/2013
• Est. Priority Date: 01/04/2012
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: EVANS, Robert W.
• Granted Patent: US 9,328,567 B2
• Time in Patent Office: Days
• US Class Current: 166/301
• CPC Class Codes: E21B 17/07 Telescoping joints for varying drill string lengths; Shock absorbers
• CPC Class Codes: E21B 31/107 using impact means for releasing stuck parts, e.g. jars
• CPC Class Codes: E21B 47/017 Protecting measuring instruments

Abstract

A downhole assembly, including a downhole tool, a downhole force-creating device, and a shock damper. The shock damper includes a hollow housing including an annular shoulder near each end and extending radially inward from the housing. The damper also includes a mandrel located at least partially inside the housing to form an annulus between the mandrel and the housing, the mandrel including an annular shoulder near each end and extending radially outward from the mandrel. A spring is located in an annular cavity formed by the annulus and between both the housing shoulders and the mandrel shoulders. The mandrel is movable relative to the housing to an expanded position in one direction and to a compressed position in the other direction.

Claims

1. A downhole assembly, including:

a downhole tool;

a downhole force-creating device;

a shock damper for the force generated from the force-creating device, the shock damper including;

a hollow housing including an annular shoulder near each end and extending radially inward from the housing;

a mandrel located at least partially inside the housing to form an annulus between the mandrel and the housing, the mandrel including an annular shoulder near each end and extending radially outward from the mandrel;

a spring located in an annular cavity formed by the annulus and between both the housing shoulders and the mandrel shoulders;

the mandrel being movable relative to the housing to an expanded position in one direction and to a compressed position in the other direction; and

the spring being compressible by a housing shoulder on one end and a mandrel shoulder on the opposite end as the mandrel moves between the expanded and compressed positions, the compression of the spring resisting relative movement between the mandrel and the housing and absorb the force moving the mandrel.

2. The downhole assembly of claim 1, wherein the housing shoulders are formed by shoulder ends attached to each end of the housing, the shoulder ends having a smaller internal dimension than the housing.

3. The downhole assembly of claim 1, wherein one mandrel shoulder is formed on the mandrel itself and the second mandrel shoulder is formed on a mandrel extension attached to the mandrel.

4. The downhole assembly of claim 1, wherein the spring includes a stack of Belleville springs.

5. The downhole assembly of claim 1, further including annular pistons on each end of the spring.

6. The downhole assembly of claim 5, wherein the annular cavity is fluid-filled and a piston includes a port that can control the flow of fluid through the piston into and out of the cavity so as to affect the dynamic response of the spring.

7. The downhole assembly of claim 6, wherein the pressure of the fluid in annular cavity is balanced with hydrostatic pressure.

8. A method of dampening the shock transferred to a downhole assembly, including:

transferring the force from the shock to a mandrel located at least partially inside a hollow housing to move the mandrel relative to the housing between an expanded position in one direction and to a compressed position in the other direction; and

resisting the movement of the mandrel between both the expanded position and the compressed position by compressing a spring to dampen the shock transferred to the downhole assembly.

9. The method of claim 8, wherein the force is created by activating a downhole force-creation device.

10. The method of claim 8, wherein the spring is located in a fluid-filled cavity, the method further including balancing the fluid in the cavity with hydrostatic pressure.

11. The method of claim 10, further comprising controlling the rate of fluid flow into and out of the cavity as the spring compresses to affect the dynamic response of the spring.

12. The method of claim 8, further including transferring the force from actuating a downhole force-creating device.

13. The method of claim 8, further including:

positioning the mandrel and housing coaxially; and

resisting the movement of the mandrel as it moves axially in both directions between the expanded and compressed positions.

14. A shock damper for a downhole force-creating device, the shock damper including

a hollow housing including an annular shoulder near each end and extending radially inward from the housing;

a mandrel located at least partially inside the housing to form an annulus between the mandrel and the housing, the mandrel including an annular shoulder near each end and extending radially outward from the mandrel;

a spring located in an annular cavity formed by the annulus and between both the housing shoulders and the mandrel shoulders;

the mandrel being movable relative to the housing to an expanded position in one direction and to a compressed position in the other direction; and

the spring being compressible by a housing shoulder on one end and a mandrel shoulder on the opposite end as the mandrel moves between the expanded and compressed positions, the compression of the spring resisting relative movement between the mandrel and the housing and absorb the force moving the mandrel.

15. The shock damper of claim 14, wherein the housing shoulders are formed by shoulder ends attached to each end of the housing, the shoulder ends having a smaller internal dimension than the housing.

16. The shock damper of claim 14, wherein one mandrel shoulder is formed on the mandrel itself and the second mandrel shoulder is formed on a mandrel extension attached to the mandrel.

17. The shock damper of claim 14, wherein the spring includes a stack of Belleville springs.

18. The shock damper of claim 14, further including annular pistons on each end of the spring.

19. The shock damper of claim 18, wherein the annular cavity is fluid-filled and a piston includes a port that can control the flow of fluid through the piston into and out of the cavity so as to affect the dynamic response of the spring.

20. The downhole assembly of claim 19, wherein the pressure of the fluid in annular cavity is balanced with hydrostatic pressure.