SELF-CIRCULATING DRILL BIT

• US 20100319995A1
• Filed: 11/06/2008
• Published: 12/23/2010
• Est. Priority Date: 11/22/2007
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Johnson, Ashley
• Granted Patent: US 8,833,490 B2
• Time in Patent Office: Days
• US Class Current: 175/57
• CPC Class Codes: E21B 10/60 characterised by conduits or nozzles for drilling fluids for roller bits E21B10/18; for percussion drill bits E21B10/38
• CPC Class Codes: E21B 21/12 using drilling pipes with plural fluid passages, e.g. closed circulation systems
• CPC Class Codes: E21B 4/006 Mechanical motion converting means, e.g. reduction gearings E21B4/10 takes precedence

Abstract

A drilling system comprising a drive shaft having a fluid flow conduit extending therethrough; a drill bit mounted for rotation by the drive shaft and having a bit face which, in use, contacts a formation to be drilled, and including a fluid flow passage with an outlet near the center of the bit face; a first fluid flow line extending from the outside of the drive shaft to the flow passage in the drill bit; and a second fluid flow line extending from the outside of the drive shaft to the flow conduit. A method of drilling a well using such a system comprise positioning the system in a borehole; rotating the drive shaft to rotate the bit; urging the bit against the formation to be drilled; and pumping drilling fluid down the borehole so as to pass though the first flow line and to exit the fluid flow passage in the drill bit via the outlet, flow over the bit face and pass into the fluid low conduit via the second fluid flow line.

Claims

1. A drilling system comprising:

a drive shaft having a fluid flow conduit extending therethrough;

a drill bit mounted for rotation by the drive shaft and having a bit face which, in use, contacts a formation to be drilled, and having a fluid flow passage with an outlet near the center of the bit face;

a first fluid flow line extending from the outside of the drive shaft to the flow passage in the drill bit; and

a second fluid flow line extending from the outside of the drive shaft to the flow conduit.

2. The system as claimed in claim 1, wherein, the drive shaft is mounted for rotation in a BHA.

3. The system as claimed in claim 2, wherein the first and second fluid flow lines extend through the BHA to the bit and drive shaft respectively.

4. The system as claimed in claim 3, wherein the fluid flow lines comprise first parts formed in the BHA and second parts formed in the bit or drive shaft respectively.

5. The system as claimed in claim 4, wherein the second part of the second passage comprises one or more holes extending from the conduit.

6. The system as claimed in claim 5, wherein the holes are be angled to the radial direction.

7. The system as claimed in claim 1, wherein a baffle is provided which extends around the periphery of the BHA near the bit, the first fluid line having an inlet which is on the opposite side of the baffle to the drill bit, and the second fluid line having an inlet between the baffle and the drill bit.

8. A method of drilling a well, comprising the steps of:

positioning a drilling system in a borehole, the drilling system comprising;

a drive shaft having a fluid flow conduit extending therethrough;

a drill bit mounted for rotation by the drive shaft and having a bit face which, in use, contacts a formation to be drilled, and having a fluid flow passage with an outlet near the center of the bit face;

a first fluid flow line extending from the outside of the drive shaft to the flow passage in the drill bit; and

a second fluid flow line extending from the outside of the drive shaft to the flow conduit;

rotating the drive shaft to rotate the bit;

urging the bit against the formation to be drilled; and

pumping drilling fluid down the borehole so as to pass though the first flow line and to exit the fluid flow passage in the drill bit via the outlet, flow over the bit face and pass into the fluid low conduit via the second fluid flow line.