WO2019016669A1

WO2019016669A1 - Method and vehicle for inspecting pipelines

Info

Publication number: WO2019016669A1
Application number: PCT/IB2018/055235
Authority: WO
Inventors: Dr. Amir ELIEZER; Yshai GABAI
Original assignee: Trymer Ltd.
Priority date: 2017-07-21
Filing date: 2018-07-16
Publication date: 2019-01-24
Also published as: EP3655764A1

Abstract

The invention relates to a method for inspecting pipelines (1), in particular for inspecting oil or gas pipelines. In further, the invention relates to an automatic guided vehicle (2), drone or submarine for inspecting pipelines by using terahertz waves.

Description

Method and Vehicle for Inspecting Pipelines

Description

Field of the Invention

The invention relates to a method for inspecting pipelines, in particular for inspecting oil or gas pipelines. In further, the invention relates to an automatic guided vehicle, drone or submarine for inspecting pipelines.

Background of the Invention Gas or oil pipelines have to be inspected regularly in order to avoid leakages, which can result in severe damages for the infrastructure and for the environment. Pipelines on the ground as well as underwater pipelines are subjected to atmospheric conditions, which may result in degradation, in particular corrosion, of the wall of the pipeline.

An optical inspection of pipelines is very time-consuming. In further, optical inspections are not, in many cases, sufficient since damages to the structure often occur, in particular due to corrosion under a coating which is applied onto the wall of the pipeline.

Object of the Invention Given this background, it is an object of the invention to provide a non-invasive inspection method for a pipeline, which can be carried out quickly, and which also enables the recognition of damages located under the coating of a pipeline that cannot be detected by an optical inspection. The method can relate to the inspection from the inside or the outside of the pipeline.

Summary of the Invention

The object of the invention is achieved by a method for inspecting pipelines, in particular oil and gas pipelines, and by an automatic guided vehicle, drone or submarine according to the subject matter of the independent claims.

Further embodiments and refinements of the invention are subject of the independent claims, the description, and the drawings.

The invention relates to a method for inspecting pipelines, wherein the pipeline is examined by a vehicle, drone or submarine from the outside or from the inside of the pipeline. Preferably, the vehicle, drone or submarine has an automatic guiding system, e.g. comprising a GPS module and/or at least one sensor for measuring the distance to a surface of the pipeline. According to an embodiment of the invention, the pipeline is examined from the inside and from the outside,

preferably simultaneously. This results in an even more reliable inspection of the entire structure of the wall of the pipeline. The pipeline can be embodied as a gas or oil pipeline.

However, the invention can also be used for all kinds of fluid pipelines, in particular water pipelines, sewage pipelines etc.

Depending on the application, the automatic guided vehicle, drone or submarine can also be manned in order to enable the option of manual operation, at least in case of a damage .

If a vehicle is used, it can be driven, according to an embodiment of the invention, on rails, or it can use the pipeline as a rail. According to another embodiment of the invention, the vehicle drives on the ground and comprises sensors for detecting the position of the pipeline, in particular distance sensors. According to the invention, the pipeline is inspected with a terahertz sensor in order to detect anomalies, which might be an indicator for damage, possibly resulting in leakage later. Terahertz waves are suitable also to detect anomalies below one or several layers of coating.

According to an embodiment of the invention, an active terahertz imaging system is used. Anomalies in the wall of the pipeline can be detected, for example, by using an automatic image processing method. In particular, an automatic edge detection can be used to identify anomalies in the structure of the pipeline.

Terahertz radiation is electromagnetic radiation whose frequency lies between the microwave and infrared regions of the spectrum. The region of the electromagnetic spectrum spanning from -100 GHz to ~10 THz, corresponding to the submillimeter wavelength range between 1 mm (high-frequency edge of the microwave band) and 100 mm (long-wavelength edge of far-infrared light) is defined as terahertz radiation .

According to an embodiment of the invention, a terahertz scanner is used, which generates an image by using time domain spectroscopy.

The terahertz radiation enters the substrate and is

collected with an appropriate lens mounted on the back of the substrate. The radiation can be detected after

transmission through the sample with an electro-optic crystal, which exhibits birefringence as a result of the incident terahertz radiation. A second time delayed and polarized laser beam will then undergo a polarization change which depends on the size of terahertz electrical and/or magnetic field at the time of incidence. This polarization change is detected with an analyzer. A full image of the sample can be obtained with the help of a CCD camera and/or other visual systems. By tuning the time delay of the second laser beam, the full time dependent terahertz signal can be recovered both in magnitude as well as phase. Terahertz waves offer non-invasive and high-resolution means for inspecting corrosion effects that may be hidden under a dielectric layer such as non-conductive paint. The terahertz radiation is able to penetrate and inspect nonconductive material for defects and is reflected from metallic materials. The radiation also reflects from interfaces that exhibit impedance discontinuities such as inclusions, pits and voids, micro cracks and any other discontinuities or mechanical defects. THz radiation can detect every type of corrosion, in particular also pitting.

According to the invention, the vehicle, drone or submarine further comprises a global positioning system.

Should an anomaly be detected, a signal is relayed to a control station, wherein the signal comprises data

representing the position of the anomaly. The transmitted data preferably also comprises an image, e.g., an image of a terahertz scanner. Based on the image, it can then be decided in a control station located away from the pipeline whether a manual inspection and/or a manual repair is necessary.

The vehicle, drone or submarine preferably comprises means for relaying its position to a control station.

The invention is also suitable for the inspection of a group of pipes. In particular, by using the position data of vehicle, a pipeline with a defect can be identified. According to an embodiment of the invention, in case of an anomaly, the pipeline is examined with X-rays or with ultrasound. Hence, the method comprises a further

inspection method which is, in most cases, not as quick as the inspection using a terahertz scanner, but which enables a more detailed view of the structure in the area of the anomaly . According of a further embodiment of the invention, the vehicle, drone or submarine further comprises a depth analyzer for measuring the thickness of a coating of the pipeline. The depth can be measures, e.g. by using

microwaves or by using a sensor, which measures the

thickness of coatings of a ferrous wall by using magnetic means or a sensors which measures the thickness of coatings of non-ferrous metal walls by using eddy currents.

According to a further embodiment of the invention, the vehicle, drone or submarine comprises means for repairing the wall of the pipeline. In particular, the vehicle, drone or submarine can comprise means for grinding or milling the wall and/or for applying the protective coating. Therefore, in some cases it is possible to perform an automatic repair of a damaged area by using the automatic guided vehicle, drone or submarine.

According to a further embodiment of the invention, the vehicle, drone or submarine comprises an optical camera for making an image or a video sequence, which is relayed to the control station. In particular, in combination with a system for an

automatic repair of the pipeline, especially by using a grinder, this repair can be surveyed by using an optical camera system.

The invention further relates to a method for inspecting pipelines, in particular to a method as described before. According to the invention, the pipeline is examined with at least one terahertz detector by emitting terahertz waves from a multitude of different angles and by measuring the signal strength of the reflected waves. It has been discovered that it is possible in a very simple and quick way to detect anomalies in the wall of the pipeline, which might be a hint for a possible defect due to degradation of the wall material, in particular due to corrosion .

It has been discovered that degradation of the wall results in a significantly weaker signal strength of the reflected wave . In order to get reflected terahertz waves at a multitude of different angles, there is, according to an embodiment of the invention provided a multitude of antennas and/or detectors which are distributed around the inner or the outer surface of the pipeline in a ring-shape fashion. According to this embodiment, preferably at least three, in particular preferred at least five antennas, which emit terahertz waves, are distributed around the surface of the pipeline .

According to another embodiment of the invention, at least one antenna, which transmits terahertz waves, is rotated around the inner or the outer surface of the pipeline. By simply measuring the signal strength, it is, according to this embodiment of the invention, not necessary to use a terahertz scanner that provides an image of the area of the anomaly . However, according to an embodiment of the invention, in a first step anomalies are quickly detected by simply

measuring the signal strength of reflected terahertz waves. Then, in a second step, the area of the anomaly is examined with an imaging system, in particular with a terahertz scanner or with an X-ray apparatus.

The invention further relates to an preferably automatic guided vehicle, drone or submarine which is in particular suitable for performing the above-described method when inspecting pipelines.

The vehicle comprises a battery, at least one terahertz sensor, in particular a terahertz scanner comprising several antennas, which are arranged around the pipeline, a global positioning system, and a transmitter for relaying data to a control station. According to a preferred embodiment of the invention, the vehicle, drone or submarine comprises an arm with a

terahertz sensor, in particular with several terahertz sensors, which at least partially extends around the pipeline to be examined.

In particular, a number of antennas is arranged around the arm and terahertz waves are emitted from different angles. This makes it possible to collect the maximum amount of information via a decoder in a limited amount of time.

The arm is preferably embodied as a telescopic arm. The arm can be extended and has preferably an annular region, which extends around the pipe at least at an angle of 180°, preferably more than 180°.

Preferably, the arm is driven by a hydraulic systems.

According to an embodiment of the invention, the vehicle, drone or submarine, in particular above-mentioned arm of the vehicle, drone or submarine, comprises a distance senor for measuring the distance to the wall of the pipeline. According to a further embodiment, the vehicle, drone or submarine, in particular the arm, comprises an optical camera and/or an X-ray apparatus.

The invention further relates to a system for inspecting pipelines, which comprises a control station and at least one vehicle, as described before. The vehicle communicates wirelessly with the control station . According to a further embodiment of the invention, the pipeline comprises a docking station for the automatic guided vehicle, drone or submarine. These docking stations can be used to charge the battery of the robot. The docking stations can also be used as a transmitting spot, which is connected to wires, external antennas, sensors and/or further internal or external docking

stations . In further, the docking stations can be used for data exchange .

This embodiment is preferably used for the inspection of underwater or underground pipelines since, in this case, it is not possible to receive a GPS signal when the robot inspects the pipe.

Such a docking station can be used to get the exact

position of the robot and/or in order to transmit data to the control station.

The docking stations are preferably inserted at the joints of two pipes.

Brief description of the drawings The subject of the invention will be described in detail referring to the schematic drawings according to Fig. 1 to Fig. 9. Fig. 1 is a schematic illustration of an automatic guided vehicle according to the invention, which performs a method for inspecting pipelines.

Fig. 2 is a detailed view of the arm of the vehicle, which comprises the antennas and receivers of a terahertz scanner .

Fig. 3 is an alternative embodiment showing the use of a drone instead of a vehicle.

Fig. 4 is an embodiment, wherein a submarine is used as transport vessel for the terahertz scanner.

Fig. 5 is an embodiment, wherein the automatic guided vehicle is a crawler for inspecting the pipeline from on the inside.

Fig. 6 shows an embodiment of an automatic guided vehicle comprising a rotatable antenna for inspecting the pipeline from the inside.

Fig. 7 shows grafts of the received terahertz signal, according to an embodiment of the invention. Fig. 8 is a three-dimensional illustration of the received signal . Fig. 9 is flow chart of the method, according to one embodiment of the invention.

Detailed description of the drawings

Fig. 1 is a schematic illustration of an inspection system for performing the inspection of a pipeline according to the invention.

The system comprises as a robot in this embodiment an automatic guided vehicle 2, which comprises an arm with, in this embodiment, a cantilever 4, which extends around the pipeline 1 and which comprises terahertz antennas.

By using terahertz waves, the structure of the pipeline 1 below any coating can be examined with a high resolution. It is possible to get a clear picture that shows the situation around a defect.

The terahertz scanner transmits from a multitude of antennas, which are arranged at various angles at the arm 3, respectively, in this embodiment, the cantilever 4 of the arm 3.

The terahertz scanner measures the amplitude from the returning waves by detecting the voltage. For example, terahertz waves with a frequency between 0.1 and 5.0 THz, preferably between 0.2 and 0.5 THz, can emitted from the antennas. By distributing the terahertz antennas at various angles, it is possible to get a picture very quickly.

The vehicle 2 as shown in Fig. 1 can be, depending on the application, be embodied as a manned or unmanned vehicle.

The vehicle 2 comprises wheels 6 and drives in this embodiment on the ground. According to another embodiment of the invention (not shown) , the vehicle 2 drives on the pipeline or on a separate rail.

The vehicle 2 comprises said arm 3 with a cantilever 4, which extends around the pipeline 1. In this embodiment, the arm 3, respectively the cantilever 4, extends around an angle of more than 180° but not around the entire pipe, so that the arm 3 can pass the pillars 5.

The automatic guided vehicle 2 is equipped with a GPS- system 7 in order to transmit the exact position of the vehicle 2 and/or in order to follow the desired path 17 of movement.

The automatic guided vehicle 2 in further comprises a battery 8 and preferably also a battery charger. The vehicle 2 comprises a data analyzer 9, which at least enables an automatic detection of anomalies, e.g. based on an automatic edge detection. The vehicle 2 can further comprise a depth analyzer 11, which can measure the thickness of a coating of the

pipeline 1. The depth analyzer 9 may comprise a sensor, e.g. a microwave sensor or a sensor, which measures the thickness of coatings of a ferrous wall by using magnetic means or a sensor, which measures the thickness of coatings of non-ferrous metal walls by using eddy currents.

The automatic guided vehicle 2 in further comprises a data transmitter 10, which enables a wireless communication with a control station 16.

In case of an automatic detected anomaly, which might be a hint for damage in the structure of the pipeline 1, the vehicle 2 can send an alert to the control station 16.

The vehicle 2 sends its position and a picture of the area of the anomaly to the control station 16. In the control station 16, it can be decided manually whether it is necessary to start a maintenance in the area of the anomaly and whether the maintenance can be performed by the vehicle 2 itself or by a maintenance crew.

The vehicle 2, preferably the arm 3 of the vehicle 2 can comprise distance sensors to hold an exact distance to the pipeline 1 when moving. In further, the vehicle 2 can optionally comprise a

moisture sensor 13, a basic tooling 14, e.g. a grinding and/or milling tooling and/or an X-ray apparatus 15, which enables the examination of a possible defect also with X- rays .

If the vehicle 2 is embodied as a manned vehicle the basic tooling 14 can comprise standard hand guided tools, which are located in a storage (not shown) of the vehicle 2.

If the vehicle is embodied as an unmanned vehicle, the basic tooling can be located on the arm 3 of the vehicle 2.

The pipeline 1 can comprise docking stations 22, which can be used to charge the battery 8 of the vehicle and/or to transmit data to the control station 16, in particular in applications in which a wireless transmission is not possible (e.g. under ground or under water) . The docking stations 22 can also include sensors or can be connected with sensors 24, 25, which are placed on the inner (sensor 25) or the outer (sensor 26) side of the pipeline 1. These sensors 24, 25, e.g. sensors measuring the magnetic field and/or the electric resistance of the hull of the pipeline, can be used additionally to the inspection with terahertz waves to collect data, which are relevant for the condition of the hull of the pipeline 1.

The sensors 24, 25 can be placed upon, below or inside a coating of the pipeline 1. The sensors 24, 25 can also be arranged face to face (not shown), e.g. for measuring the thickness of the wall of the pipeline . Fig. 2 is a detailed view of the cantilever 4 of the arm.

The cantilever 4 comprises an extension 19, which enables that the cantilever 4 covers an area of more than 180°. In further, the cantilever 4 comprises terahertz

antennas/sensors 18, which are distributed around the inner contour of the cantilever 4.

In further, the cantilever 4 can also comprise at least one distance sensor 12, which enables to keep a constant gap to the pipe. The distance sensor 12 can be embodied as an optical sensor, as an ultrasound sensor and/or as a

capacitive or inductive sensor. Arm 3 and/or cantilever 4 are preferably operated by a hydraulic system (not shown) .

Fig. 3 shows another embodiment of the invention, wherein, instead of an automatic guided vehicle as robot, a drone 20 is used for examining the pipeline 1 with terahertz waves.

In this embodiment, the drone 20 carries the arm 3 with the cantilever 4. In this schematic drawing, the drone 20 is embodied as a quadcopter . The drone 20 can comprise all features, which are described referring to the automatic guided vehicle 2 shown in Fig. 1 (except the wheels) .

Fig. 4 shows further alternative embodiment, wherein instead of an automatic guided vehicle or a drone, a submarine 21 carries a terahertz scanner. In this embodiment, the submarine 21 carries the arm 3 with cantilever 4, which extends around the pipeline 1.

The submarine 21 enables an automatic inspection of

pipelines 1, which are located under the water surface.

The submarine 21 can also comprise all features, which are described referring to the automatic guided vehicle 2 shown in Fig . 1. However, the submarine 21 can be embodied to inspect pipelines also without contact to the control station and/or can be connected with an antenna on the water surface in order to keep contact with the control station 16 and/or in order to receive GPS-signals.

In further, the submarine can comprise a depth sensor (not shown) for measuring the water depth.

When using a submarine 21, the terahertz sensors and antennas should be in direct contact with the wall of the pipeline 1 in order to avoid that radiation is absorbed by the surrounding water.

Fig. 5 is a schematic view of an embodiment, wherein the automatic guided vehicle 2 is embodied as a crawler.

The crawler comprises wheels 6 and automatically drives through the interior of the pipeline. The crawler comprises a multitude of antennas which emit terahertz waves and which are distributed around the inner surface of the pipeline 1.

By using such a crawler, it is possible to inspect the interior hull of the pipeline very quickly.

Fig. 6 is an alternative embodiment of an automatic guided vehicle for inspecting the pipeline 1 from the inside. In this embodiment, the automatic guided vehicle 2, which is also embodied as a crawler with wheels 6, comprises a rotatable antenna, which is, in this embodiment, a

rotatable shield 23. The shield 23 comprises at least one terahertz antenna and at least one terahertz receiver.

The shield 23 is rotated along the inner surface of the pipeline 1. The vehicles shown in Fig. 5 or Fig. 6 can also be combined with the vehicle, drone or submarine according to any of Fig. 1 to Fig. 4, in order to inspect the pipeline from the inside as well as from the outside.

Fig. 7 shows graphs of the received signal according to an embodiment of the invention.

In this embodiment, a pulsed terahertz radiation with a wavelength between 0.2 and 0.5 THz is used. The strength of the reflected waves is measured by using a receiver. The received signal is processed with a sampling rate between 5 and 1 kHz, preferably between 10 and 100 Hz. The graphs show the received signal (in volt) of a

terahertz radiation of a steel surface, which had been immersed into the salt solution for a period of ten days of 0.0, 3.5, 5.0, 7.5 and 10 % . The higher the concentration of the salt, the more

corrosion occurs.

It can be seen that the signal of the surface which had been immersed into water without salt is much higher than the signal of the surfaces which had been immersed in salt water, resulting in increased corrosion.

It can also be seen that it is possible to conclude very quickly the degree of corrosion in order to determine the position of areas that have to be examined in more detail in order to identify a leakage or a pre-leakage. Fig. 8 is a three-dimensional diagram showing the signal strength (in volt) of the reflected terahertz waves in relation to the corrosion of the surface.

As discussed with reference to Fig. 7, steel surfaces having a different degree of corrosion had been produced by immersing the surfaces into a NaCl-solution . Of course, any other electrolyte, which results in an increased corrosion, could be used.

Fig. 8 shows that the amplitude of the received terahertz waves is dependent on the degree of corrosion, i.e., the higher the corrosion, the lower the amplitude of the reflected signal. Surfaces with a higher degree of

corrosion result in a lower reflection of terahertz waves.

This enables a very reliable and quick analysis of the condition of the steel surface, also below a coating of the hull material.

Fig. 9 is flow chart of the method of inspecting pipelines, according to an embodiment of the invention. As a first step, anomalies in the condition of the wall material of the pipeline are detected by using terahertz waves .

The inspection is done simply by emitting a terahertz radiation at various angles around the inner or the outer surface of the pipeline. In case of a signal strength below a pre-defined threshold value, the automatic guided vehicle, drone or submarine is stopped and at least the position is transmitted to the control station.

Also, data representing the strength of the signal in the area of the anomaly can be transmitted. As a next step, the area of the anomaly is examined in more detail by using an imaging system. A terahertz scanner can be used as an imaging system or, as it is in this case, an X-ray apparatus. The image is relayed to the control station and in the control station it can be decided manually or automatically whether a repair in the area of the anomaly is necessary.

If a repair is necessary it is, according to one embodiment of the invention, possible to repair the damage

automatically by using a grinder and/or a milling tool which removes the corrosion.

As a last step, the repaired area is protected with a sealing. The sealing can also be applied by the automatic guided vehicle, drone or submarine. List of reference numerals

1. pipeline

2. vehicle

3. arm

4. cantilever

5. pillar

6. wheel

7. GPS

8. battery

9. data analyzer

10. data transmitter

11. depth analyzer

12. distance sensor

13. moisture sensor

14. tooling (grinded and/or milling)

15. X-ray

16. control station

17. path

18. antenna / sensor

19. extension

20. drone

21. submarine

22. docking station

23. shield

24. sensor

25. sensor

Claims

Claims :

1. Method for inspecting pipelines, in particular oil or gas pipelines, wherein the pipeline is examined by an preferably automatic guided vehicle, drone or

submarine from the inside and/or the outside of the pipeline with a terahertz detector; said vehicle, drone or submarine comprising a global positioning system;

and wherein in case of a detected anomaly, a signal is relayed to a control station, wherein said signal comprises data representing the position of the anomaly .

2. Method for inspecting pipelines according to the

preceding claim, wherein, in case of an anomaly, the pipeline is examined with X-rays and/or with

ultrasonic means.

3. Method for inspection pipelines according to any of the preceding claims, wherein, at least in case of an anomaly, an image of the area of the anomaly is relayed to a control station.

4. Method for inspection pipelines according to any of the preceding claims, wherein the vehicle, drone or submarine comprises means for repairing the wall of the pipeline and/or wherein the vehicle, drone or submarine comprises an optical camera and wherein an image or a video sequence at least of the area of the anomaly is relayed to the control station.

Method for inspecting pipelines, in particular method according to any of the preceding claims, wherein the pipeline is examined with a terahertz detector by emitting terahertz waves from a multitude of different angles and by measuring the signal power of the reflected waves.

. Method for inspecting pipelines according to any of the preceding claims, wherein a terahertz radiation with a frequency between 0.1 and 5 THz is emitted.

7. Vehicle, drone or submarine, in particular for

performing a method for inspecting pipelines according to any of the preceding claims, comprising a battery, at least one terahertz sensor, a global positioning system and a transmitter for relaying data to a control station.

8. Vehicle, drone or submarine according to the preceding claim, comprising an arm with terahertz sensors which at least partially extends around a pipeline to be examined, in particular an arm which is embodied as a telescopic arm.

Vehicle, drone or submarine according to any of the preceding claims, further comprising a distance sensor for measuring the distance to the wall of a pipeline, in particular a distance sensor which is located on said arm according to claim 8, an optical camera and/or an X-ray apparatus.

10. System for inspecting pipelines, comprising a control station and at least one vehicle according to any of the preceding claims.