AC COILED TUBING RIG WITH AUTOMATED DRILLING SYSTEM

• US 20070246261A1
• Filed: 04/19/2007
• Published: 10/25/2007
• Est. Priority Date: 04/20/2006
• Status: Active Grant

• Current Assignee: Nabors Canada Ulc (Nabors Industries Limited)
• Original Assignee: Nabors Canada Ulc (Nabors Industries Limited)
• Inventors: LOWE, Derek Joseph, ZIEBART, Cory Jason, O'BRIEN, Peter Daniel
• Granted Patent: US 7,677,331 B2
• Time in Patent Office: Days
• US Class Current: 175/26
• CPC Class Codes: E21B 19/22 Handling reeled pipe or rod units, e.g. flexible drilling pipes lifting or hauling appliances using two or more cooperating endless chains B66D3/003
• CPC Class Codes: E21B 44/02 Automatic control of the tool feed E21B44/005, E21B44/10 take precedence

Abstract

A method of automatic drilling of a well with coil tubing or drill pipe tubing utilizes AC motors coupled to variable frequency drives controlled by a programmable logic controller. For example, a coil tube injector is supported in a mast for injecting coil tube from a reel and into a wellbore for drilling the wellbore. The AC motors for the injector are driven for controlling a rate of injection of coil tube by the injector for maintaining at least one drilling parameter such as weight-on-bit, differential mud pressure or rate of penetration. The AC motor for the reel is also controlled for driving the reel and maintaining a relative rate of coil tube supplied from the reel to the injector. Drawworks and a top drive supported by the draworks can also be equipped with AC motors and variable frequency drives for controlling a drilling rate for maintaining at least one of the drilling parameters.

Claims

1. A method of automatic drilling a well comprising:

supporting a coil tube injector in a mast for injecting coil tube from a reel and into a wellbore for drilling the wellbore;

controlling a first variable frequency drive for controlling a first AC motor driving the injector for controlling a rate of injection of coil tube by the injector for maintaining at least one drilling parameter; and

controlling a second variable frequency drive for controlling a second AC motor driving the reel for maintaining a relative rate of coil tube supplied from the reel to the injector.

2. The method of claim 1 wherein the at least one drilling parameter is selected from the group consisting of weight-on-bit (WOB), differential pressure (Δ

P) and rate-of-penetration (ROP).

3. The method of claim 2 wherein the drilling parameter is WOB comprising receiving in-hole and out-hole force at the coil tube and controlling the first VFD for maintaining WOB.

4. The method of claim 3 wherein the in-hole and out-hole force at the coil tube is measured at the injector.

5. The method of claim 3 comprising:

placing a string of coil tube in the well with a drill bit at a bottom of the well;

determining a tare string weight;

setting a desired WOB;

measuring a string weight while drilling;

establishing the difference between the tare string weight and the measured string weight while drilling for establishing the WOB and controlling the first VFD for maintaining the WOP.

6. The method of claim 2 wherein the drilling parameter is Δ

P comprising determining Δ

P and controlling the first VFD for maintaining Δ

P.

7. The method of claim 6 comprising:

placing a drill bit at a bottom of the well;

determining a tare mud pressure;

setting a Δ

P;

measuring a drilling mud pressure while drilling;

establishing the difference between the tare mud pressure and the measured drilling mud pressure for controlling the first VFD for maintaining the Δ

P.

8. The method of automatic drilling of claim 2 wherein the drilling parameter is ROP comprising receiving coil position from the injector and controlling the first VFD for maintaining ROP.

9. The method of automatic drilling of claim 2 further comprising receiving one or more of in-hole and out-hole force at the injector, coil tube position and mud pressure controlling the first VFD and the second VFD for maintaining ROP.

10. The method of claim 1 wherein the controlling of the first VFD and second VFD comprises providing a programmable logic controller for controlling the first VFD and second VFDs.

11. The method of claim 10 further comprising:

measuring one or more measured inputs from string weight, string rate-of-penetration and mud pressure; and

receiving the one or more measured inputs at the programmable logic controller for controlling the at least one drilling parameter.

12. The method of claim 11 further comprising:

using a proportional/integral/derivative (PID) algorithm for

receiving the one or more measured inputs, and

controlling the first VFD and second VFDs for controlling the speed of the first AC motor and the second AC motor for maintaining the at least one drilling parameter.

13. The method of claim 1 further comprising:

supporting a top drive in the mast and raising and lowering the top drive with drawworks for drilling the wellbore with drill pipe tubing;

controlling a third variable frequency drive for controlling a third AC motor for driving the top drive for at least making and breaking drill pipe connections; and

controlling a fourth variable frequency drive for controlling a fourth AC motor for driving the drawworks for maintaining at least one drilling parameter.

14. The method of claim 13 wherein the at least one drilling parameter is selected from the group consisting of weight-on-bit (WOB), differential pressure (Δ

P) and rate-of-penetration (ROP).

15. The method of claim 14 wherein the drilling parameter is WOB comprising receiving in-hole and out-hole force at the drill pipe and controlling the first VFD for maintaining WOB.

16. The method of claim 15 wherein the in-hole and out-hole force at the drill pipe is measured at the drawworks.

17. The method of claim 15 comprising:

placing a string of drill pipe in the well with a drill bit at a bottom of the well;

determining a tare string weight;

setting a desired WOB;

measuring a string weight while drilling;

establishing the difference between the tare string weight and the measured string weight while drilling for establishing the WOB and controlling the first VFD for maintaining the WOP.

18. The method of claim 14 wherein the drilling parameter is Δ

P comprising determining Δ

P and controlling the first VFD for maintaining Δ

P.

19. The method of claim 18 comprising:

placing a drill bit at a bottom of the well;

determining a tare mud pressure;

setting a Δ

P;

measuring a drilling mud pressure while drilling;

establishing the difference between the tare mud pressure and the measured drilling mud pressure for controlling the first VFD for maintaining the Δ

P.

20. The method of automatic drilling of claim 14 wherein the drilling parameter is ROP comprising receiving coil position from the injector and controlling the first VFD for maintaining ROP.

21. The method of automatic drilling of claim 14 further comprising receiving one or more of in-hole and out-hole force at the drawworks, drill pipe position and mud pressure controlling the first VFD and the second VFD for maintaining ROP.

22. The method of claim 13 wherein the controlling of the first VFD and second VFD comprises providing a programmable logic controller for controlling the first VFD and second VFDs.

23. The method of claim 22 further comprising:

measuring one or more measured inputs from string weight, string rate-of-penetration and mud pressure;

receiving the one or more measured inputs at the programmable logic controller for controlling the at least one drilling parameter.

24. The method of claim 22 further comprising:

using a proportional/integral/derivative (PID) algorithm for

receiving the one or more measured inputs, and

controlling the first VFD and second VFDs for controlling the speed of

the first AC motor and the second AC motor for maintaining the at least one drilling parameter.

25. A drilling rig comprising:

a reel for supplying coil tube;

an injector supported in a mast for injecting the coil tube into a wellbore for drilling therewith;

a first AC motor and a first variable frequency drive for controlling the rate of injection of coil tube by the injector;

a first sensor for establishing measurements of rate of injection; and

a second AC motor and a second variable frequency drive for controlling the rate of coil tube supplied from the reel;

a second sensor for establishing measurements of the rate of coil tube supplied from the reel;

a programmable logic controller (PLC) for controlling the first and second VFD'"'"'s, wherein

the PLC receives at least the rate of injection and controls the first VFD for maintaining at least one drilling parameter, and

the PLC receives at least the reel'"'"'s speed of rotation and controls the second VFD for maintaining rate of coil tube supplied relative to the rate of injection.

26. The drilling rig of claim 25 further comprising:

a top drive supported in the mast,

a drawworks for raising and lowering the top drive for drilling the wellbore with drill pipe;

a third variable frequency drive for controlling a third AC motor for driving the top drive for at least making and breaking drill pipe connections; and

a fourth variable frequency drive for controlling a fourth AC motor for driving the drawworks for maintaining at least one drilling parameter.