Apparatus and Method for Determining Corrected Weight-On-Bit

• US 20100319992A1
• Filed: 06/19/2009
• Published: 12/23/2010
• Est. Priority Date: 06/19/2009
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Trinh, Tu Tien, Sullivan, Eric
• Granted Patent: US 8,245,793 B2
• Time in Patent Office: Days
• US Class Current: 175/40
• CPC Class Codes: E21B 44/005 Below-ground automatic control systems

Abstract

In one aspect, a method of determining a corrected weight-on-bit is provided, which method, in one embodiment, may include: drilling a wellbore with the drill bit; determining a weight-on-bit while drilling the wellbore; determining a pressure differential across an effective area of the drill bit while drilling the wellbore; and determining the corrected weight-on-bit from the determined weight-on-bit and the determined pressure differential.

Claims

1. A method of determining a corrected weight on a drill bit (weight-on-bit) during drilling of a wellbore, comprising:

determining a first weight-on-bit while a fluid flows through the drill and no applied weight-on-bit, using a sensor in the drill bit;

determining a second weight-on-bit with the sensor in the drill bit while drilling the wellbore using the drill bit; and

determining the corrected weight-on-bit from the determined first weight-on-bit and the second weight-on bit.

2. The method of claim 1, wherein the corrected weight-on-bit is determined by subtracting the first determined weight-on-bit from the second determined weight-on-bit.

3. The method of claim 1, wherein the corrected weight-on-bit is determined by one of:

processing signals from the sensor downhole or on the surface.

4. The method of claim 1, wherein determining the first weight-on-bit comprises:

determining a temperature of the fluid flowing through drill bit;

determining acceleration of the drill bit; and

processing signals from the sensor in the drill to determine the first weight-on-bit when the determined temperature meets a selected criterion and the determined acceleration meets a selected criterion.

5. The method of claim 4 further comprising:

determining the temperature using a temperature sensor in the drill bit; and

determining the acceleration using an accelerometer in the drill bit.

6. A drill bit comprising:

a sensor in the drill bit for determining a weight-on-bit; and

a processor configured to;

determine a first weight-on-bit using the measurements made by the sensor with a fluid flowing through the drill bit and no weight applied to the drill bit;

determine a second weight-on-bit using measurements from the sensor while drilling the wellbore using the drill bit; and

determine a corrected weight-on-bit from the determined first weight-on-bit and the second weight-on bit.

7. The drill bit of claim 6, wherein the sensor is disposed in a shank of the drill bit configured to measure weight-on-bit.

8. The drill bit of claim 7, wherein the processor is configured to determine the corrected weight-on-bit by subtracting the first weight on-bit from the second weight-on-bit.

9. The drill bit of claim 8, wherein the processor is enclosed in a module in the drill bit.

10. The drill bit of claim 9 further comprising a data communication device coupled to the processor and configured to transmit data from the drill bit to a location outside the drill bit.

11. A method of determining a corrected weight on a drill bit (weight-on-bit) during drilling of a wellbore, comprising:

drilling a wellbore with the drill bit;

determining a weight-on-bit while drilling the wellbore;

determining a pressure differential across an effective area of the drill bit while drilling the wellbore; and

determining the corrected weight-on-bit from the determined weight-on-bit and the determined pressure differential.

12. The method of claim 11, wherein determining the pressure differential comprises determining pressure differential between a pressure inside the drill bit and a pressure outside the drill bit.

13. The method of claim 11, wherein determining the pressure differential comprises using a sensor having a first sensing element sensing pressure at the inside of the drill bit and a second sensing element sensing pressure at the outside the drill bit.

14. The method of claim 13, wherein the first and second sensing elements are disposed in a shank of the drill bit.

15. The method of claim 11, wherein determining the corrected-weight-on-bit comprises processing signals from a weight-on-bit sensor and signals from a differential pressure sensor by a processor located at one of:

inside the drill bit and outside the drill bit.

16. An apparatus for use in drilling a wellbore, comprising:

a drill bit body having a fluid passage therethrough;

a first sensor in the drill bit configured to measure weight-on-bit;

a second sensor in the drill bit body configured to measure pressure differential across an effective area of the drill bit; and

a processor configured to;

determine a first weight-on-bit from the measurements of the first sensor and a second weight-on-bit from the measurements of the measurements of the pressure differential; and

determine corrected weight-on-bit using the determined first weight-on-bit and the second weight-on-bit.

17. The apparatus of claim 16, wherein the second sensor comprises a first sensing element configured to measure pressure inside the drill bit and a second sensing element configured to measure pressure outside the drill bit.

18. The apparatus of claim 16 further comprising a memory for storing the corrected weight-on-bit.

19. The drill bit of claim 16 further comprising a communication device coupled to the processor and configured to transmit data from the drill bit to a location outside the drill bit.

20. The apparatus of claim 19, wherein the processor is located at one of:

inside the drill bit; and

outside the drill bit.