LMI-based control of stick-slip oscillations in drilling

Patent metadata

Field	Value
Publication number	US-10619472-B2
Application number	US-201715456108-A
Country	US
Kind code	B2
Filing date	Mar 10, 2017
Priority date	Sep 11, 2014
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

A control system for controlling stick-slip oscillations in a drilling system is disclosed. The control system includes a processor and a memory communicatively coupled to the processor with computer program instructions stored therein. The instructions are configured to, when executed by the processor, cause the processor to receive a communication including a value of a drilling system parameter, determine based on the value of the drilling system parameter, a value for a torque to be applied to a drill string to reduce the effect of stick-slip oscillations, and transmit to a drive system the value for the torque to be applied by the drive system. The value for the torque to be applied by the drive system is determined by solving a set of linear matrix inequalities including a disturbance minimization linear matrix inequality, a first magnitude constraint linear matrix inequality, and a second magnitude constraint linear matrix inequality.

First claim

What is claimed is:

1. A control system for controlling stick-slip oscillations in a drilling system, comprising:
a processor; and
a memory communicatively coupled to the processor with computer program instructions stored therein, the instructions configured to, when executed by the processor, cause the processor to:
receive a communication including a value of a drilling system parameter;
determine, based on the value of the drilling system parameter, a value for a torque to be applied to a drill string to reduce the effect of stick-slip oscillations, wherein the value for the torque is determined by solving a set of linear matrix inequalities including a disturbance minimization linear matrix inequality, a first magnitude constraint linear matrix inequality, and a second magnitude constraint linear matrix inequality; and
transmit to a drive system the value for the torque to be applied to the drill string by the drive system; wherein the disturbance minimization linear matrix inequality comprises:

[

A
i

⁢
Q

+

Q
T

⁢

A
i
T

+

B
i

⁢
Y

+

Y
T

⁢

B
i
T

+

E
i

⁢

E
i
T

Q
T

⁢

C
T

CQ

-

η
2

⁢
I

]

≤

0
⁢

∀
i

=
1

,
…
⁢

,

p
.

2. The system of claim 1 , wherein the drilling system parameter includes at least one of angular position of a drive system of the drilling system, the rotational speed of the drive system, angular position of the drill string, rotational speed of the drill string, angular position of a drill bit of the drilling system, or rotational speed of the drill bit.

3. The system of claim 1 , wherein the drilling system receives the communication including the value of the drilling system parameter from a drive system of the drilling system, sensors associated with the drill string, or sensors associated with a drill bit of the drilling system.

4. The system of claim 1 , wherein the computer program instructions are configured to, when executed by the processor, cause the processor to solve the set of linear matrix inequalities using interior point methods.

5. A control system for controlling stick-slip oscillations in a drilling system, comprising:
a processor; and
a memory communicatively coupled to the processor with computer program instructions stored therein, the instructions configured to, when executed by the processor, cause the processor to:
receive a communication including a value of a drilling system parameter;
determine, based on the value of the drilling system parameter, a value for a torque to be applied to a drill string to reduce the effect of stick-slip oscillations, wherein the value for the torque is determined by solving a set of linear matrix inequalities including a disturbance minimization linear matrix inequality, a first magnitude constraint linear matrix inequality, and a second magnitude constraint linear matrix inequality; and
transmit to a drive system the value for the torque to be applied to the drill string by the drive system; wherein the first magnitude constraint linear matrix inequality comprises:

[

1

e
⁡

(
0
)

T

e
⁡

(
0
)

Q

]

≥
0.

6. The system of claim 5 , wherein the drilling system parameter includes at least one of angular position of a drive system of the drilling system, the rotational speed of the d

Assignees

• Univ Texas

Inventors

• Harris Matthew W
• Acikmese Behcet
• Van Oort Eric

Classifications

• E21B47/024

  of devices in the borehole (determining slope or direction of the borehole E21B47/022) · CPC title

• G05B2219/45129

  Boring, drilling · CPC title

• G05B19/416

  characterised by control of velocity, acceleration or deceleration (G05B19/19 takes precedence) · CPC title

• E21B44/04 Primary

  in response to the torque of the drive {; Measuring drilling torque (E21B44/06 takes precedence; measuring stresses in a well bore pipe E21B47/007)} · CPC title

• E21B44/00 Primary

  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 · CPC title