Changing set points in a resonant system

Patent metadata

Field	Value
Publication number	US-10409300-B2
Application number	US-201414899569-A
Country	US
Kind code	B2
Filing date	Jun 26, 2014
Priority date	Jun 27, 2013
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A method for changing a set point of a system where period of a dominant resonance of the system is determined, a change profile for the set point change is processed; a time period for the set point change based on the period of the dominant resonance in order to minimize excitation of the dominant resonance is also processed; and the set point change is actioned according to the processed change profile and the time period.

First claim

The invention claimed is:

1. A method for changing a set point of a system in a borehole, comprising:
determining the period of a dominant resonance of the system;
processing a change profile for the set point change;
determining a time period for the set point change based on the period of the dominant resonance in order to minimize excitation of the dominant resonance; and
performing the set point change according to the change profile and the time period.

2. The method of claim 1 , wherein the time period comprises a multiple of the period of the dominant resonance.

3. The method of claim 2 , wherein the change profile comprises a linear change profile, and the time period is an integer multiple of the period of the dominant resonance.

4. The method of claim 2 , wherein the time derivative of the change profile has a half-period of a sine-wave, and the time period is an integer-plus-a-half multiple of the period of the dominant resonance.

5. The method of claim 1 , wherein the change profile is symmetric about the mid-time of the change.

6. The method of claim 1 , wherein the determination of the time period for the set point change is performed by taking the Fourier transform of the time derivative of the change profile.

7. The method of claim 1 , wherein the borehole system comprises a drillstring.

8. The method of claim 1 , wherein the borehole system comprises a wireline.

9. The method of claim 1 , wherein the borehole system comprises an electro-submersible pump.

10. A control system for changing a set point of a system in a borehole, comprising:
a computer processor configured to:
determine a period of a dominant resonance of the system;
process a change profile for a set point change from sensed properties; and
determine a time period for the set point change based on the period of the dominant resonance in order to minimize excitation of the dominant resonance; and
a controller configured to control the system to perform the set point change according to the change profile and the time period.

11. The control system of claim 10 , further comprising one or more sensors to sense properties of the system and/or the borehole, the determination of the period of the dominant resonance of the system and/or the processing of the change profile being based on the sensed properties.

12. A rig or a tool having the control system of claim 11 .

13. The control system of claim 10 , wherein the system comprises a managed pressure drilling system.

14. The control system of claim 10 , wherein the system comprises a drilling system.

15. An automated system for operating one or more systems in a borehole, wherein the automated system comprises the control system of claim 10 .

Assignees

• Schlumberger Technology Corp

Inventors

• Jeffryes Benjamin Peter
• Cook John
• Gahlings Steven

Classifications

• 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

• G05B15/02

  electric · CPC title

• G05D19/02 Primary

  characterised by the use of electric means · CPC title

• E21B47/0006

  Fixed Constructions · mapped topic

• E21B43/128

  Adaptation of pump systems with down-hole electric drives · CPC title