Autodriller bit protection system and method

• US 20050133259A1
• Filed: 12/23/2003
• Published: 06/23/2005
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Varco I/P Incorporated (NOV, Inc.)
• Original Assignee: Varco I/P Incorporated (NOV, Inc.)
• Inventors: Koederitz, William L.
• Granted Patent: US 7,100,708 B2
• Time in Patent Office: Days
• US Class Current: 175/27
• CPC Class Codes: E21B 44/00 Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions

Abstract

A controller provides an automatic bit protection sequence for an autodriller that can be initiated during the initial stage of set down of the bit within the formation. The automatic protection sequence establishes a setpoint for a parameter of interest (such as weight on bit, ROP, torque) associated with operation of the drilling system and then initiates a gradual increase in that parameter in order to achieve the setpoint. The bit protection sequence may be adjustable so that varying degrees of gradualness may be selected. The controller of the autodriller may also be provided with measured data for torque, rate of penetration (ROP) and/or the differential pressure of the mud motor of the drilling system. Each of these parameters is provided with a predetermined setpoint, and each may be selected as the controlling parameter for operation of the autodriller.

Claims

1. A method for controlling the placement of weight on a bit of a drilling assembly during the start of a drilling operation, the method comprising the steps of:

a) establishing a setpoint for a parameter of interest related to the placement of weight on the bit;

b) monitoring the parameter of interest; and

c) increasing actual weight on bit in a gradual manner until the setpoint is reached for the parameter of interest.

2. The method of claim 1 wherein the actual weight on bit is increased in a gradual manner by increasing the actual weight on bit in discrete increments.

3. The method of claim 2 wherein there are increments of time between the additions of discrete increments of weight on bit.

4. The method of claim 1 wherein the actual weight on bit is increased to the setpoint within a target time period.

5. The method of claim 1 wherein the actual weight on bit is increased in a gradual manner by establishing a plurality of intermediate setpoints below the setpoint and sequentially moving the actual weight on bit along the intermediate setpoints.

6. The method of claim 1 wherein the setpoint is a setpoint derived from rate of penetration of the bit.

7. The method of claim 1 wherein the parameter of interest is actual weight on bit and the setpoint is a setpoint fof actual weight on bit.

8. The method of claim 1 wherein the parameter of interest is torque on a drilling string associated with the drilling assembly, and the setpoint is a setpoint for torque on a drilling string associated with the drilling assembly.

9. The method of claim 1 wherein the parameter of interest is differential pressure of a mud motor for supplying drilling mud to the bit, and the setpoint is a setpoint for differential pressure of a mud motor for supplying drilling mud to the bit.

10. The method of claim 1 wherein the setpoint for the parameter of interest is selected from among a plurality of drilling parameter setpoints.

11. The method of claim 10 wherein the setpoint for the parameter of interest is selected from among said plurality of drilling parameter setpoints by a driller.

12. The method of claim 10 wherein the setpoint for the parameter of interest is selected from among said plurality of drilling parameter setpoints by a programmable controller.

13. A system for providing protection to a drill bit in a drilling assembly during the start of a drilling operation, the system comprising:

a) a load sensor for measuring a parameter of interest associated with operation of the drilling assembly;

b) a controller to receive the measured parameter of interest and to compare the measured parameter of interest to a predetermined setpoint for the parameter of interest; and

c) the controller further adjusting the actual weight on bit to reach the setpoint in a gradual manner.

14. The system of claim 13 wherein the controller adjusts the parameter of interest by increasing the weight on bit in discrete increments of weight.

15. The system of claim 14 wherein the controller further adjusts the parameter of interest by separating each discrete increment of weight by a predetermined time period.

16. The system of claim 13 wherein the parameter of interest is the actual rate of penetration of the drill bit.

17. The system of claim 13 wherein the parameter of interest in torque on a drill string associated with the drilling assembly.

18. The system of claim 13 wherein the parameter of interest is actual differential mud pressure for a mud motor associated with the drilling assembly to provide drilling mud to the drill bit.

19. The system of claim 13 wherein the parameter of interest is actual weight on bit.

20. The system of claim 13 wherein the controller selects a control setpoint from among a set of setpoints for drilling parameters consisting of weight on bit, rate of penetration, torque on a bottom hole assembly, and differential mud pressure for a mud motor associated with the system to provide drilling mud to the drill bit.

21. A computer readable medium containing instructions that, when executed, cause a controller to control operation of a drilling assembly according to the following method:

a) establishing a setpoint for control of a parameter of interest associated with operation of the drilling assembly;

b) monitoring the parameter of interest; and

c) increasing the parameter of interest in a gradual manner until the setpoint is reached.

22. The computer readable medium of claim 21 wherein the setpoint is established by selecting from among a set of setpoints for drilling parameters consisting of weight on bit, rate of penetration, torque on a bottom hole assembly, and differential mud pressure for a mud motor associated with the system to provide drilling mud to the drill bit.

23. The computer readable medium of claim 21 wherein the parameter of interest is increased in a gradual manner by increasing the parameter of interest in discrete increments.

24. The computer readable medium of claim 23 wherein there are increments of time between the additions of discrete increments of the parameter of interest.

25. The computer readable medium of claim 21 wherein the parameter of interest is increased to the setpoint within a target time period (max t).

26. The computer readable medium of claim 21 wherein the setpoint is a setpoint for the weight on bit.

27. The computer readable medium of claim 21 wherein the setpoint is a setpoint for rate of penetration of the bit.

28. The computer readable medium of claim 21 wherein the setpoint is a setpoint for torque on a drill string associated with the drilling assembly.

29. The method of claim 21 wherein the setpoint is a setpoint for differential pressure of a mud motor for supplying drilling mud to the bit.

30. The method of claim 22 wherein the setpoint is selected from among said plurality of drilling parameter setpoints by a driller.

31. The method of claim 22 wherein the setpoint is selected from among said plurality of drilling parameter setpoints by a programmable controller.