Claims
- 1. A drill bit, comprising:a bit body having a plurality of ports therein arranged to provide a flow path between an interior of a drill string and the exterior of the bit body; and at least one flow relief disposed in one of the ports, the at least one flow relief adapted to change a total flow area of the drill bit upon application of a selected fluid flow condition to the drill bits, wherein the at least one flow relief comprises a biased pressure relief valve.
- 2. The drill bit as defined in claim 1 wherein the selected flow condition comprises a predetermined differential pressure across the drill bit.
- 3. The drill bit as defined in claim 1 wherein the selected flow condition comprises a predetermined total flow volume across the drill bit.
- 4. The drill bit as defined in claim 1 wherein the at least one flow relief comprises a rupture disk.
- 5. The drill bit as defined in claim 1 wherein the biased pressure relief valve is adapted to open above a selected differential pressure.
- 6. The drill bit as defined in claim 1 wherein the biased pressure relief valve is adapted to open within a selected range of differential pressure.
- 7. The drill bit as defined in claim 1 wherein the at least one flow relief comprises an orifice in an orifice body having an erodible material disposed therein, the erodible material adapted to be worn away after a selected volume of fluid has passed therethrough.
- 8. The drill bit as defined in claim 7 wherein the erodible material comprises mild steel.
- 9. A method for changing a total flow area of a drill bit, comprising:pumping drilling fluid through the drill bit; and operating a flow relief disposed in the bit to change the total flow area of the bit, wherein the flow relief comprises a biased pressure relief valve.
- 10. The method as defined in claim 9 wherein operating the flow relief comprises increasing a differential pressure across the drill bit to at least a predetermined value.
- 11. The method as defined in claim 9 further comprising decreasing the total flow area of the bit by causing the differential pressure to drop below the predetermined value.
- 12. The method as defined in claim 9 wherein the operating the flow relief comprises maintaining a differential pressure across the drill bit within a predetermined range.
- 13. The method as defined in claim 9 wherein the operating the flow relief comprises causing a selected total volume of fluid to flow through the flow relief.
- 14. A drill bit, comprising:a bit body having a plurality of ports therein arranged to provide a flow path between an interior of a drill string and the exterior of the bit body; at least one cutting element operatively coupled to the bit body and at least one biased pressure relief valve disposed in one of the ports.
- 15. The drill bit as defined in claim 14 wherein the biased pressure relief valve is adapted to open above a selected differential pressure.
- 16. The drill bit as defined in claim 14 wherein the biased pressure relief valve is adapted to open within a selected range of differential pressure.
CROSS-REFERENCE TO RELATED APPLICATIONS
This invention claims priority from U.S. Provisional Application Ser. No. 60/304,555, filed on Jul. 11, 2001.
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A |
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Foreign Referenced Citations (1)
Number |
Date |
Country |
2000-120364 |
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JP |
Non-Patent Literature Citations (1)
Entry |
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Provisional Applications (1)
|
Number |
Date |
Country |
|
60/304555 |
Jul 2001 |
US |