AU2009201725A1

AU2009201725A1 - Underwater Pipe Monitoring apparatus

Info

Publication number: AU2009201725A1
Application number: AU2009201725A
Authority: AU
Inventors: Brett Robson Manners
Original assignee: TOTAL MARINE TECHNOLOGY Pty LT
Current assignee: TOTAL MARINE TECHNOLOGY Pty Ltd
Priority date: 2008-04-30
Filing date: 2009-04-30
Publication date: 2009-11-19
Anticipated expiration: 2029-04-30
Also published as: AU2009201725B2; MY181795A

Description

Pool Section 29 Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT application Number: Lodged: Invention Title: Underwater Pipe Monitoring Apparatus The following statement is a full description of this invention, Including the best method of performing it known to us: 1 UNDERWATER PIPE MONITORING APPARATUS FIELD OF THE INVENTION The present invention relates to apparatus which can be employed underwater to monitor the condition of an underwater pipe. The apparatus of the 5 invention is envisaged for remote use, for instance in conjunction with a Remotely Operated Underwater Vehicle (ROV). BACKGROUND TO THE INVENTION Underwater pipes, such as those use for the transfer of oil and gas from off-shore production facilities to on-shore processing facilities, are typically 10 formed from stainless steel. The stainless steel pipes are encased with concrete to provide additional weight. Lengths of pipe are welded together to form a continuous pipeline. The welding takes place during construction of the pipeline at sea, and therefore the resulting welded joints are not encased with concrete. Instead, a 'field joint' is 15 surrounded by a sealant material. Typically, this may include a bitumous layer surrounded by a plastic or foam sealant. Underwater pipes are subject to corrosion. A variety of measures are put in place to alleviate this corrosion, such as the use of sacrificial anodes and of appropriate field joints. Nonetheless, undersea pipelines have a limited life-span. 20 It is highly desirable to determine the degree of corrosion of a pipeline. Such information can allow a determination of the remaining useful life of the pipeline, and can allow corrective action to be taken before a leak forms in the pipeline. Various non-destructive testing techniques have been developed in order to determine the degree of corrosion of the pipeline. These include the use 25 of x-ray technology and of ultra-sound readings. Effective use of these technologies has, to date, required a diver, or a team of divers, to employ sensing equipment about a pipeline. Some pipelines, however, are located at ocean depths so great that they can not be safely accessed by divers. It is thus desirable to have a monitoring 30 device which can be employed remotely, such as by an ROV. The present invention seeks to provide such a device.

2 SUMMARY OF THE INVENTION In accordance with a first aspect of the present invention there is provided a pipeline monitoring apparatus having a first body portion and a second body portion, each of the first and second body portions having a concave inner side, 5 with a plurality of rolling elements disposed on the inner side, the first and second body portions being hinged together and moveable between an open configuration in which the monitoring apparatus can be brought about a pipe and a closed configuration in which the rolling elements locate about the pipe and permit rotation of the apparatus about the pipe. Advantageously, this can permit 10 measurement tools located on the apparatus to be manoeuvred about the entire pipe circumference. It will be appreciated that the apparatus of the invention allows rotational movement about the pipe of at least 3600. Preferably, the apparatus includes a drive mechanism coupled to at least one of the rolling elements, such that operation of the drive mechanism causes 15 rotation of the apparatus about the pipe. In a preferred embodiment of the invention, the drive mechanism includes a drive shaft which extends along the apparatus in an axial direction, with the drive shaft also acting as the hinge connecting the first and second body portions. Usefully, this simplifies the construction of the apparatus and reduces its weight. 20 Some or all of the rolling elements may be driven by the drive mechanism. In a preferred embodiment, each of the rolling elements is coupled to a sprocket, which is driven by a chain drive connected to a drive sprocket on the drive shaft. This arrangement encourages steady and controllable rotation of the apparatus about the pipe. It also allows for failure of one or more chains to occur whilst still 25 allowing the apparatus to function. Idler rolling elements may be included to reduce the complexity of the drive mechanism. It is preferred that the rolling elements are in the form of wheels located at either side of each body portion. Preferably, the wheels are located such that, on 30 average, each wheel is within 600 of its neighbour (measured about the pipe circumference) when the apparatus is in the closed position. More preferably, each wheel is spaced from its neighbour by an average of about 45*. It will be appreciated that this will require the apparatus to have eight wheels located on 3 either side, or 16 wheels in total. Having wheels relatively closely spaced assists the apparatus to achieve smooth rotation about the pipe, even when the pipe surface is highly irregular. The apparatus includes provision for at least one measuring tool to be 5 mounted thereto. Where X-ray analysis is required, the apparatus may include an X-ray device mounted within the first body portion and an X-ray film receptacle within the second body portion. The film receptacle may be part-cylindrical, to allow an X ray film to be located about a portion of the pipe. The film receptacle is positioned so as to be diametrically spaced from the X-ray device when the 10 apparatus is in the closed configuration. Where ultrasound analysis is required, the apparatus may include an ultrasound site preparation device and an ultrasonic probe. The site preparation device and the probe are preferably angularly displaced from each other about a circumference of the apparatus - that is, are located at the same axial location 15 but are circumferentially spaced. The ultrasound site preparation device includes a scraping tool. Preferably, the scraping tool has a cutting edge which is arranged to rotate about an axis of the scraping tool. The cutting edge may have two cutting portions substantially on either side of the axis, with each of the cutting portions oriented in the same 20 rotational direction. In a preferred form of the invention, one of the cutting portions extends past the axis, to ensure consistent cutting across the centre of a cut circle. The scraping tool and the ultrasonic probe each include respective axial movement drives. Preferably, at least one of the body portions includes an orientation 25 determination device. Preferably, the orientation determination device provides a visual determination of apparatus orientation which can be viewed by an ROV mounted camera. This device may be a weighted pointer which points vertically, set against a set of markings relating to different circumferential positions. In a preferred embodiment, the apparatus includes an axial positioning 30 means for the measuring tool. This enables some adjustment of the axial position of the measuring tool relative to the body portions.

4 BRIEF DESCRIPTION OF THE DRAWINGS It will be convenient to further describe the invention with reference to the accompanying drawings which illustrate preferred embodiments of the apparatus of the present invention. Other embodiments are possible, and 5 consequently, the particularity of the accompanying drawings is not to be understood as superseding the generality of the preceding description of the invention. In the drawings: Figure 1 is an isometric view of an underwater pipe monitoring apparatus in accordance with the present invention, shown in an open configuration; 10 Figure 2 is an isometric view of the underwater pipe monitoring apparatus of Figure 1, shown in a closed configuration; Figure 3 is a side view of the underwater pipe monitoring apparatus of Figure 1, shown in the closed configuration; Figure 4 is a cross section through the underwater pipe monitoring apparatus as 15 shown in Figure 3; Figure 5 is a side view of the underwater pipe monitoring apparatus of Figure 1, shown in the open configuration during use; Figure 6 is a cross section through the underwater pipe monitoring apparatus as shown in Figure 5; 20 Figure 7 is a side view of the underwater pipe monitoring apparatus of Figure 1, shown in the closed configuration during use; Figure 8 is a cross section through the underwater pipe monitoring apparatus as shown in Figure 7; Figure 9 is an X-ray film cassette for use in conjunction with the underwater pipe 25 monitoring apparatus of Figure 1; Figure 10 is a deployment basket for use in conjunction with the underwater pipe monitoring apparatus of Figure 1; Figure 11 is an exploded view of a scraping tool within the underwater pipe monitoring apparatus of Figure 1; and 30 Figure 12 is a perspective of the scraping tool of Figure 11 when assembled. DESCRIPTION OF PREFERRED EMBODIMENT Referring to the figures, there is shown a pipeline monitoring apparatus 10. The apparatus 10 is composed of a first body portion 12 and a second body portion 5 14. Each of the body portions 12, 14 has a concave inner side 16. The concave inner sides 16 are part cylindrical, and are arranged to locate about a portion of pipe 20. It will be appreciated that the inner sides are provided with the same degree of curvature as the pipe 20 to be monitored. 5 Each of the body portions 12, 14 include a generally part-cylindrical frame 22, bordered at either side by a wheel locating channel 24. Located outside the channel 24 are a plurality of part-cylindrical buoyancy elements 26, which may be formed from a syntactic foam. The first and second body portions 12, 14 are joined by a hinge shaft 28. The 10 hinge shaft 28 extends in a longitudinal direction between respective upper edges of the wheel locating channels 24. At either end of the hinge shaft 28 the wheel locating channel 24 of the first body portion 12 is offset from that of the second body portion 14, allowing the hinge shaft 28 to pass through both body portions 12, 14. The respective frames 22 of the first and second body portions 12, 14 15 have bushes (not shown) located along the hinge shaft 28, which support the hinge shaft 28 whilst allowing it to rotate freely. The first and second body portions 12, 14 are connected by clamping means in the form of hydraulic rams 30 which extend across the hinge shaft 28. The hydraulic rams 30 control relative movement of the first and second body portions 20 12, 14 about the hinge shaft 28. When the rams 30 are in a retracted position, as shown in Figure 1, the first and second body portions 12, 14 are relatively splayed such that the inner sides 16 can readily pass over a pipe 20. This represents an open configuration of the apparatus 10. When the rams 30 are in an extended position, as shown in Figure 2, the first and second body portions 12, 14 are 25 arranged such that the inner sides 16 are substantially coaxial. This represents a closed configuration of the apparatus 10. In the closed configuration, the inner sides 16 form a substantially cylindrical bore which, in use, locates around a pipe 20. Within each of the wheel locating channels 24 are a plurality of rolling elements, 30 in the form of wheels 32 each having a sprocket 34 coaxially mounted thereto. In the preferred embodiment of the drawings, each of the wheel locating channels 24 includes four wheels 32 'spaced circumferentially about the inner side 16. The wheels 32 are arranged so as to be in rolling, frictional contact with the pipe 20 6 when the apparatus 10 is in the closed configuration about the pipe 20. It will be appreciated that, in this condition, the apparatus 10 is supported about the pipe 20 by eight wheels at either side. Each wheel is therefore spaced on average at 450 from its neighbour. It is considered that such spacing will facilitate smooth 5 rotation about the pipe 20. In an alternative embodiment, where each channel 24 includes three wheels, the average space is 600. This may also provide acceptable smoothness of rotation. Each of the sprockets 34 is arranged to be driven by a chain 36. The apparatus 10 includes four chains 36, one for each wheel locating channel 24. The wheel 10 locating channels 24 each include positioning rollers 38 located between each wheel 32 to ensure the chain 36 maintains contact with all four sprockets 34. The hinge shaft 28 includes four drive sockets 40, aligned respectively with the four chains 36. In this way, rotation of the hinge shaft 28 causes rotation of each of the wheels 32. The hinge shaft 28 is thus also a drive shaft. 15 The apparatus 10 includes a drive motor 42 mounted to the hinge shaft 28 by a suitable gearing arrangement. It will be appreciated that the size of the drive sockets 40 can be chosen to provide a suitable gearing effect for driving of the wheels 32. Rotational movement of the hinge shaft 28 by the drive motor 42 is thus 20 translated to the wheels 32 by the chains 36. Each of the wheels is arranged to rotate simultaneously, at the same rate. In the event that one chain 36 fails, four of the wheels 32 will cease being driven and will instead operate as idler wheels. It is envisaged that this will not have a significant impact on the operation of the apparatus 10. 25 The apparatus 10 includes two orientation determination devices in the form of indicators 44. The indicators 44 are mounted to the outside of the buoyancy elements 26 at one end of the apparatus 10, a respective indicator 44 being mounted to each of the first and second body portions 12, 14. In the embodiment of the drawings, the indicators 44 are simply weighted pointers 46 which are 30 oriented by gravity into a vertical position. Noting the angle of the pointers 46 with respect to the body portions 12, 14 provides an indication of the rotational position of the apparatus 10 about the pipe 20. It is envisaged that a camera on an associated ROV will be equipped to view these indicators.

7 Within the pipeline monitoring apparatus 10 of the preferred embodiment two distinct monitoring tools are provided. It will be appreciated that alternative tools may be provided in other embodiments. Nonetheless, the arrangement of the tools of the preferred embodiment is considered to introduce additional novel 5 features to the present application. The two monitoring tools provided in the embodiment of the drawings are an X ray photograph tool and an ultrasound analysis tool. The X-ray photograph tool has two elements - an X-ray device 50 and an X-ray film receptacle 52. The X-ray device 50 is mounted centrally within the frame 22 10 of the first body portion 12, and is oriented towards the centre of curvature of the inner side 16 of the first body portion 12, and hence the pipe 20. The X-ray film receptacle 52 is located on the second body portion 14, and is formed between the two wheel locating channels 24 of the second body portion 14. The receptacle 52 includes two curved outer tracks 54, located on either side 15 of the body portion 14, with a curve following that of the wheel locating channels 24, and thus the pipe 20. The receptacle is thus part-cylindrical. The receptacle 52 includes a longitudinal stopping bar 56 which extends along a lower edge of the inner side 16 of the second body portion 14. The receptacle 52 also includes a releasable catch 58 defining an upper 20 boundary of the receptacle 52. The receptacle 52 is arranged to receive a cassette 60 including an X-ray film, and to allow the cassette 60 and thus the film to bend around the circumference of the pipe 20. A suitable cassette 60 is shown in Figure 9. When the apparatus 10 is in the closed configuration, the receptacle 52 is diametrically opposed to the 25 X-ray device 50. The ultrasound analysis tool has two components: an ultrasound site preparation device 66 and an ultrasonic probe 68. The preparation device 66 and the probe 68 are both located on the first body portion 12, near to one of the buoyancy elements 16. The preparation device 66 and the probe 68 have the same axial or 30 longitudinal location, and lie on the same circumference of the apparatus 10, but are angularly or circumferentially spaced by about 720. The site preparation device 66 includes a scraping tool 76 which can both be rotated about its axis and urged in an axial direction. In use, the site preparation 8 device can be used to drill or scrape through a field joint of the pipeline. The scaping tool is made of a suitable quality stainless steel, and operated at a sufficient speed, to enable removal of the field joint but not of damaging the pipe 20. The scraping tool 76 can thus be used to expose a circular inspection site of 5 the pipe 20. A preferred embodiment of the scraping tool 76 is shown in Figures 11 and 12. The scraping tool 76 is formed from two plate members 78. Each of the plate members 78 has a cutting edge 80 located along, and protruding from, an outer surface thereof. The cutting edge 80 of a first plate member 78 extends more 10 than half way along its outer surface. The cutting edge 80 of a second plate member 78 extends less than half way along its outer surface. The arrangement is such that when the two plate members 78 are brought together, as shown in Figure 12, an outer edge of the scraping tool is formed from the two cutting edges 80. The cutting edges 80 are oriented in opposite directions, such that rotation of 15 the scraping tool 76 causes both of the cutting edges 80 to bear against a field joint of the pipe 20. It will be appreciated that the axis of rotation of the scraping tool passes through the cutting edge 80 of the first plate member 78, rather than through a junction of the two cutting edges 80. This is to prevent the creation of a burr at the centre of 20 a scraped circle. The site preparation device 66 may also include a water jet which acts to wash scraped particles away from the inspection site. The ultrasonic probe 68 is arranged to be axially extendable between a retraced position within the frame 22 and an extended position in which it can contact the 25 exposed inspection site of the pipe 20. In an alternative embodiment (not shown), the monitoring tools may be mounted on axial rails of the monitoring apparatus 10, and associated with an axially arranged hydraulic ram. Such an arrangement will allow the axial location of the monitoring tools relative to the body portions 12, 14 to be adjusted in use as 30 required. In use, the apparatus 10 is deployed within a basket 70, as shown in Figure 10. The basket 70 includes a pipe section 72. The apparatus 10 is deployed in its 9 closed configuration, clamped about the pipe section 72. The basket 70 is taken to an appropriate location on the sea bed using an ROV. When in the location, the rams 30 are operated to move the apparatus 10 into the open position. The ROV is then able to lift the apparatus off the pipe section 72, 5 and to lower it over the pipe 20 to be monitored. Operation of the rams 30 moves the apparatus into the closed position, where the wheels 32 are in frictional engagement with the pipe 20. Operation of the drive motor 42 then allows the apparatus 10 to be positioned in a suitable rotational position about the pipe 20. The precise rotational position can 10 be determined by observation of the indicators 44. The X-ray photograph tool of the present invention is arranged to take a series of photographs about the pipe 20 circumference. The basket 70 is preferably arranged with receptacles for five X-ray film cassettes 60. As each X-ray photograph is taken, the ROV arm can be used to exchange film cassettes 60 15 between the basket 70 and the film cassette receptacle 52 of the apparatus 10. The indicators 44 of the embodiment of the drawings have five marks placed at 720 angles. Each of the resulting positions of the pointers 46 correspond to rotational positions of the apparatus 10 in which X-ray photographs should be taken. 20 The ultrasound analysis tool is arranged to be used on a single position of the pipe 20. When the pointers 46 are pointing to one of the indicator 44 marks then the preparation device 66 can be engaged. Once the inspection site is prepared, rotation of the apparatus 10 to the next indicator mark 44 will allow use of the probe 68 at the inspection site. 25 The probe 68 may be employed with a camera to allow precise angular positioning with respect to the inspection site. In use, it is anticipated that movement of the apparatus 10 and of the tools are all effected hydraulically. In development of a prototype, it has been found that the apparatus requires more hydraulic circuits than are readily available. In order to 30 address this problem, early embodiments of the device were provided with a hydraulic switching device (not shown) in the form of a lever which could be manipulated by the ROV arm. The switching device transferred hydraulic flow from the rams 30 to the tools of the apparatus 10, whilst retaining sufficient 10 pressure to maintain the apparatus in the closed position. It will be appreciated that the tools were only used when the apparatus 10 was in the closed position, and therefore the hydraulic circuits could be used for different functions without compromising performance. 5 In later embodiments the device has been fitted with controls to allow direct operation from the surface, rather than via an ROV, which has largely obviated the need for the switching device. Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention. 10

Claims

1. A pipeline monitoring apparatus having a first body portion and a second body portion, each of the first and second body portions having a concave inner side, with a plurality of rolling elements disposed on the inner side, the first and 5 second body portions being hinged together and moveable between an open configuration in which the monitoring apparatus can be brought about a pipe and a closed configuration in which the rolling elements locate about the pipe and permit rotation of the apparatus about the pipe.

2. A pipeline monitoring apparatus as claimed in claim 1, wherein the 10 apparatus includes a drive mechanism coupled to at least one of the rolling elements, such that operation of the drive mechanism causes rotation of the apparatus about the pipe.

3. A pipeline monitoring apparatus as claimed in claim 2, wherein the drive mechanism includes a drive shaft which extends along the apparatus in an axial 15 direction, with the drive shaft also acting as the hinge connecting the first and second body portions.

4. A pipeline monitoring apparatus as claimed in claim 3, wherein each of the rolling elements is coupled to a sprocket, which is driven by a chain drive connected to a drive sprocket on the drive shaft. 20

5. A pipeline monitoring apparatus as claimed in any preceding claim, wherein the rolling elements are in the form of wheels located at either side of each body portion.

6. A pipeline monitoring apparatus as claimed in claim 5, wherein the wheels are located such that, on average, each wheel is within 600 of its neighbour 25 (measured about the pipe circumference) when the apparatus is in the closed position. 12

7. A pipeline monitoring apparatus as claimed in claim 6, wherein each wheel is spaced from its neighbour by an average of about 450*.

8. A pipeline monitoring apparatus as claimed in any preceding claim, wherein the monitoring apparatus includes measuring tools attached thereto, the 5 axial position of the measuring tools relative to the first and second body portions being adjustable.

9. A pipeline monitoring apparatus as claimed in any preceding claim, wherein the apparatus includes an X-ray device mounted within the first body portion and an X-ray film receptacle within the second body portion.

10 10. A pipeline monitoring apparatus as claimed in any preceding claim, wherein the apparatus includes an ultrasound site preparation device and an ultrasonic probe.

11. A pipeline monitoring apparatus as claimed in any preceding claim, wherein at least one of the body portions includes an orientation determination 15 device. TOTAL MARINE TECHNOLOGY PTY LTD WATERMARK PATENT & TRADE MARK ATTORNEYS