Turbine Driven Hammer that Oscillates at a Constant Frequency

• US 20100065334A1
• Filed: 11/23/2009
• Published: 03/18/2010
• Est. Priority Date: 11/21/2005
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Hall, David R., Dahlgren, Scott, Marshall, Jonathan
• Granted Patent: US 8,297,378 B2
• Time in Patent Office: Days
• US Class Current: 175/107
• CPC Class Codes: E21B 10/62 characterised by parts, e.g. cutting elements, which are detachable or adjustable E21B10/64 takes precedence; for roller bits E21B10/20; for augers E21B10/44
• CPC Class Codes: E21B 4/14 Fluid operated hammers

Abstract

In one aspect of the present invention a hammer assembly comprises a substantially coaxial jack element with a distal end extending beyond a working face of a drill bit. A porting mechanism within the bore comprises a first and second disc substantially contacting along a flat interface substantially normal to the axis of rotation. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports in the second disc. As the first disc rotates, the sets of ports are adapted to route a drilling fluid into a piston chamber where the porting mechanism causes the jack element to repeatedly extend further beyond the working surface of the drill bit at a constant frequency.

Claims

1. A hammer assembly, comprising;

a jack element substantially coaxial with an axis of rotation of a drill bit, the jack element comprises a distal end extending beyond a working face of the drill bit;

a porting mechanism within the bore comprising a first and second disc substantially contacting along a flat interface substantially normal to the axis of rotation;

the first disc attached to a turbine which is adapted to rotate the first disc with respect to the second disc;

the first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports of the second disc as the first disc rotates, the sets of ports are adapted to route a drilling fluid into a piston chamber;

wherein the porting mechanism causes the jack element to repeatedly extend further beyond the working surface of the drill bit at a constant frequency.

2. The hammer assembly of claim 1, wherein the drilling fluid is routed by the first and second set of ports through a first channel to the proximal end of the piston chamber adjacent to the second disc.

3. The hammer assembly of claim 2, wherein a piston in the piston chamber is in mechanical communication with a jack element at the distal end of the piston chamber.

4. The hammer assembly of claim 3, wherein the mechanical communication comprises a rigid mechanical connection, an intermittent mechanical connection, a hydraulic connection, or a combination thereof.

5. The hammer assembly of claim 1, wherein the drilling fluid passes through a second channel adjacent the aligned first and third set of ports, which leads to the distal end of the piston chamber.

6. The hammer assembly of claim 5, wherein drilling fluid directs the piston towards the proximal end of the chamber.

7. The hammer assembly of claim 2, wherein when drilling fluid is forced out of the piston chamber, the fluid exits the proximal end of the piston chamber through a set of exhaust ports of the first disc.

8. The hammer assembly of claim 7, wherein the set of exhaust ports have the characteristic to absorb energy from redirecting the drilling fluid flow.

9. The hammer assembly of claim 8, wherein the characteristic to absorb energy is dependent on the geometry which may include expanding diameters from entrance to ext, an exit not parallel to the entrance, an exit on the outer diameter of the first disc, or any combination thereof.

10. The hammer assembly of claim 9, wherein the characteristic to absorb energy causes a resistance which increases at a non-linear rate with an increase in drilling fluid flow.

11. The hammer assembly of claim 1, wherein the constant frequency is predetermined by a ratio between impact energy of the jack element and wear on the jack element.

12. The hammer assembly of claim 1, wherein the constant frequency is achieved through a combination of turbine blade geometry and exhaust ports geometry.

13. The hammer assembly of claim 1, wherein the second set of ports comprises a smaller flow area, then the first set of ports.

14. The hammer assembly of claim 1, wherein the hammer assembly comprises a lubrication system.

15. The hammer assembly of claim 15, wherein the lubrication system comprises a shaft that extends from the second disc to a lubricant reservoir adjacent to the turbine.

16. The hammer assembly of claim 15, wherein the lubrication system comprises a bypass channel that is formed adjacent to the turbine and extends to beyond a sealing element located adjacent to the first disc and also extends to the lubricant reservoir.

17. The hammer assembly of claim 17, wherein the bypass channel comprises a set of tortuous paths which limit the amount of drilling fluid allowed to pass.

18. The hammer assembly of claim 17, wherein the drilling fluid directed to the reservoir applies a force to direct the lubricant along the shaft.

19. The hammer assembly of claim 17, wherein the drilling fluid directed to beyond the sealing element creates a pressure balance which limits the amount of lubricant that passes through the sealing element.