Method of testing an unbonded flexible pipe

Patent metadata

Field	Value
Publication number	US-10962148-B2
Application number	US-201615751246-A
Country	US
Kind code	B2
Filing date	Aug 5, 2016
Priority date	Aug 10, 2015
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

The present invention relates to a method of testing an unbonded flexible pipe. The unbonded flexible pipe has a length and a longitudinal axis and comprises, from the inside and out, an internal armour layer, an internal pressure sheath, at least one external amour layer and an outer sheath. At least one of the layers comprises an optical sensor connected to an optical monitoring system and at least one of the armour layers is a metallic and electrically conductive amour layer. The method makes it possible to test an electrical heating system and an optical sensor substantially simultaneously.

First claim

What is claimed is:

1. A method of testing an unbonded flexible pipe having a length and a longitudinal axis and comprising, from the inside and out, an internal armour layer, an internal pressure sheath, at least one external amour layer and an outer sheath, said pipe comprising at least one thermal sensor connected to a monitoring system and at least one of the armour layers is a metallic and electrically conductive armour layer, said method comprises:
connecting the metallic armour layer to an electric power source;
sending an electric current through the metallic armour layer;
measuring the temperature in the flexible pipe by using the thermal sensor and processing the results in the monitoring system to obtain a temperature profile for the pipe; and
comparing the obtained temperature data to a reference temperature profile and determining if the flexible pipe meets the required specifications,

wherein electric power is sent through the metallic armour layer during a first period, followed by a second period wherein the electric power is switched off.

2. The method according to claim 1 where the thermal sensor is based on the measurement of optical properties of a glass fibre.

3. The method according to claim 1 , wherein the internal armour layer on the inside of the internal pressure sheath is a metallic and electrically conductive armour layer.

4. The method according to claim 1 , wherein the current is sent through the internal armour layer on the inside of the pressure sheath.

5. The method according to claim 1 , wherein the external armour layer is a metallic and electrically conductive armour layer and the electric current is returned to the electric power source via the external armour layer in the flexible pipe.

6. The method according to claim 1 , wherein the output from the optical sensor is compared to a reference temperature profile obtained under well-defined operational conditions.

7. The method according to claim 1 , wherein the reference temperature profile is established by calculating the thermal properties of the unbonded flexible pipe.

8. The method according to claim 1 , wherein the unbonded flexible pipe comprises more external armour layers selected from pressure armour layers and tensile armour layers.

9. The method according to claim 1 , wherein the current is returned to the power source via the pressure armour layer, the tensile armour layer, or a combination of both.

10. The method according to claim 1 , wherein the annulus between the internal pressure sheath and the outer sheath is filled with an inert gas.

11. The method according to claim 1 , wherein the annulus between the internal pressure sheath and the outer sheath is filled with a liquid.

12. The method according to claim 1 , wherein the metallic armour layers comprises one or more optical sensors.

13. The method according to claim 1 , wherein the optical sensor is housed in a housing.

14. The method according to claim 1 , wherein the method further comprises:
determining if the function of the thermal sensor and the condition of the metallic armour layers of the flexible pipe meet the required specifications by determining if the obtained temperature profile is within ranges set by the reference temperature profile.

15. A method of testing an unbonded flexible pipe having a length and a longitudinal axis and comprising, from the inside and out, an internal armour layer, an internal pressure sheath, at least one external amour layer and an outer sheath, said pipe comprising at least one thermal sensor connected to a monitoring system and at least one of the armour layers is a metallic and electrically conductive amour layer, said method comprises:
connecting the metallic amour layer to an electric power source;
sending an electric current through the metallic armour layer;
measuring the temperature in the flexible pipe by using the thermal sensor and processing the results in the monitoring system to obtain a temperature profile for the pipe; and
comparing the obtained temperature data to a reference temperature profile and determining if the flexible pipe meets the required specifications, wherein electric power is sent through the metallic armour layer during a first period, followed by a second period wherein the electric power is switched off, preferably the first period is in the range of about 10 minutes to about 10 hours preferably the second period is in the range of about 10 minutes to about 10 hours.

16. A system for testing an unbonded flexible pipe having a length and a longitudinal axis and comprising, from the inside and out, an internal armour layer, an internal pressure sheath, at least one external armour layer and an outer sheath and at least one temperature sensor connected to a monitoring system, and at least one of the armour layers is a metallic and electrically conductive armour layer, said system comprises:
the unbonded flexible pipe, and
an electric power source and the temperature sensor mounted in the unbonded
flexible pipe and connected to the monitoring system,

wherein the metallic armour layer is adapted for connection with the power source for heating the armour layer by sending an electric current through the metallic armour layer, and the monitoring system is adapted for processing measurements from the temperature sensor to obtain a temperature profile for the pipe, comparing the obtained temperature profile to a reference temperature profile obtained from a reference pipe under well-defined operational conditions in a factory where the pipe is manufactured and relating to surrounding temperature, humidity and measured length, and determining if the function of the thermal sensor and the condition of the metallic armour layers of the flexible pipe meet the required specifications by determining if the obtained temperature profile is within ranges set by the reference temperature profile.

17. The system according to claim 16 , wherein the temperature sensor is an optical sensor.

18. The system according to claim 17 , wherein the condition of the metallic armour layer(s) and the function of the optical sensor is determined on the basis of the output from the optical sensor.

19. The system according to claim 16 , wherein the internal armour layer inside the internal pressure sheath is a metallic armour layer connected to the electric power source.

20. The system according to claim 16 , wherein the at least one external armour layer is a metallic armour layer and connected to the electric power source.

21. The system according to claim 16 , wherein the metallic armour layer is cyclically heated and cooled.

22. A system for testing an unbonded flexible pipe having a length and a longitudinal axis and comprising, from the inside and out, an internal armour layer, an internal pressure sheath, at least one external armour layer and an outer sheath and at least one temperature sensor connected to a monitoring system, and at least one of the armour layers is a metallic and electrically conductive armour layer, said system comprises:
the unbonded flexible pipe, and
an electric power source and the temperature sensor mounted in the unbonded
flexible pipe and connected to the monitoring system,

wherein the metallic armour layer is adapted for connection with the power source for heating the armour layer by sending an electric current through the metallic armour layer, and the monitoring system is adapted for processing measurements fro

Assignees

• Nat Oilwell Varco Denmark Is

Inventors

• Glejbol Kristian
• Eilersen Michael
• Straarup Anders
• Cappeln Christian Ditlev

Classifications

• G01M3/002

  by using thermal means · CPC title

• G01M5/0025

  of elongated objects, e.g. pipes, masts, towers or railways (G01M5/0058 takes precedence) · CPC title

• G01M3/38

  by using light (G01M3/02 takes precedence) · CPC title

• F16L53/37

  the heating current flowing directly through the pipe to be heated · CPC title

• F16L11/082 Primary

  two layers · CPC title