APPARATUS AND METHOD FOR DETERMINING THE PHYSICAL CONDITION OF A PIPELINE

Abstract: Apparatus (1) for determining the condition of a pipeline is comprised of a carrier means (2), a gauge plate (3) and a detection means (7). The apparatus (1) is further provided with a transmission means (4) to indicate to a remote location the detection of the presence of physical defects in the pipeline. When the apparatus (1) passes a physical defect in the pipeline, the gauge plate (3) which may be elastomeric, will be deformed or bent. As a result, the detection means will communicate with the transmission means, which in turn will indicate the defect to a remote location. The transmission means may be in the form of an acoustic, electro-magnetic, nucleonic or mechanical system. The apparatus allows the physical condition of a pipeline to be monitored without having to retrieve the pig from the pipeline to visually examine it.

Description: Apparatus and Method for determining the physical condition of a pipeline The present invention relates to a method and apparatus for determining the physical condition of a pipeline. In particular, the present invention relates to a pipeline pig that can be used for such a purpose. The incidence of damage to pipelines results in huge cost to the oil industry in terms of lost production and maintenance. The detection of defects or damage can be done using a number of techniques, for example our co- pending Application 9812422.5 teaches the use of chemical sensors to detect the occurrence and extent of corrosion. This type of sensor is, however, not suitable for detecting physical damage such as a dent or ovality. Currently, the most favoured technique for detecting physical damage is via the use of a pipeline pig on which is mounted an aluminium disc. Typically, the disc is formed from soft aluminium set to a diameter of 95% of the minimum internal diameter of the pipeline. The discs are usually several millimetres thick and may be provided with a series of radial slits to give approximately 6-8 "petals". When the pig is used in a pipeline there are two possible outcomes: 1. The pig emerges from the pipeline undamaged, indicating that the pipeline is undamaged; or 2. The pig emerges from the pipeline with its gauge plate deformed, indicating that there has been damage to the pipeline. There are, however, a number of disadvantages with the use of this type of pig. Firstly, to determine the presence of any damage the pig has to be examined visually which means that it must be recovered from the pipeline. This is unsatisfactory if the pipeline is subsea and several miles in length. In addition, the pig is not provided with means for relaying the precise location of any damage or defects in the pipeline. Furthermore, once the pig has passed one section of damage and part of the plate has been displaced, the pig may be unable to register the presence of any further damage . Damage to a pipeline can, alternatively, be detected by physical inspection of the external surface by an individual such as a diver. Again, however, the dimensions and location of typical pipelines make this method of damage detection unsatisfactory. It would therefore be desirable to be able to use apparatus that is able to detect the occurrence of pipeline damage and send a signal indicating such to a remote centre. It would also be desirable for such apparatus to indicate the location of any damage in the pipeline. This feature would be particularly desirable where the pipeline is several miles in length. It is an object of the present invention to provide apparatus that can be used to accurately detect the presence of one or more pipeline defects, wherein the apparatus does not have to be retrieved from the pipeline or visually examined to detect said faults. It is a further object of the present invention to provide apparatus for detecting the condition of a pipeline wherein the apparatus may be operated and monitored from a remote location. According to a first aspect of the present invention there is provided apparatus for determining the physical condition of a pipeline, wherein the apparatus comprises a gauge plate mounted on a mobile carrier, the gauge plate being provided with detection means for detecting deformation of the gauge plate resultant from physical defects in the pipeline, and the apparatus further comprising transmission means to indicate to a remote location the detection of the presence of physical defects. Optionally the detection means is a mechanical device. Optionally the detection means is a strain gauge. Alternatively the detection means is in the form of a conductive element formed by an electrically or optically conductive material. Preferably the conductive element is applied to or mounted on the rear face of the gauge plate. Optionally the detection means is in the form of an electrical circuit formed by tape such as fracture detection tape or glass break tape. However, any suitable tape may be used. Where a tape is used as the detection means, the tape is fixed to the plate such that a closed circuit is formed while the plate remains undamaged and an open circuit is formed when the plate becomes damaged. The detection means communicates with the transmission means when the gauge plate is deformed. The transmission means is in the form of an acoustic, electromagnetic, nucleonic or mechanical system, and transmits information to a remote location. In addition, the apparatus may be operated from said remote location. The carrier may be, but is not limited to, a pipeline pig- Optionally the gauge plate is made from an elastomeric material. Preferably the plate is provided with a series of radial slits which divide the plate into individual "petals". Preferably the apparatua is propelled throught he pipeline by pipeline fluid. According to second aspect of the present invention there is provided a method of determining the physical condition of a pipeline comprising the steps of: a) passing a carrier through the pipeline, the carrier comprising a gauge plate and detection means for detecting deformation of the gauge plate; and b) transmitting a signal to a remote location upon said detection by the detection means. The data may also be stored on the carrier, and collected and analysed once said carrier has passed through the desired section of pipeline. In order to provide a better understanding of the present invention, an embodiment will now be described by way of example only with reference to the accompanying Figures in which: Figure 1 illustrates a pipeline pig in accordance with the present invention; Figure 2 illustrates a view of a gauge plate that can be mounted on a pipeline pig in accordance with the present invention; and Figure 3 illustrates the pipeline pig of Figure 1 in use in a pipeline. Referring firstly to Figure 1 apparatus for determining the condition of a pipeline is generally depicted at 1 comprising a carrier means 2, a gauge plate 3 and a transmitter 4. The carrier means 2 is further provided with supports 5. Figure 2 illustrates a face view of the gauge plate 3. The gauge plate 3 is provided with a central aperture 6 for connection with the transmitter 4 of Figure 1. In addition the gauge plate 3 is provided with detection means 7, slits 8 and a connector 9. The connector 9 provides a connection between the detection means 7 and the transmitter 4. In one embodiment the gauge plate 3 is made from an elastomeric material. The gauge plate 3 will be deformed upon passing a physical defect in the pipeline. However, as the gauge plate 3 is made from an elastomeric material, it will return to its original shape after passing the physical defect. This is an advantage as the apparatus 1 will not be detrimentally affected upon passing a first defect in the pipeline and will therefore be able to register the presence of other physical defects further along the pipeline. Figure 3 illustrates the apparatus 1 in use in a pipeline 10. In the Figure the apparatus 1 has passed a dent 11 in the wall of the pipeline 10. The gauge plate 3 has been bent at point 12 by the action of the apparatus 1 passing the dent 11. The arrow indicates the direction of movement of the apparatus 1 through the pipeline 10. The apparatus 1 is inserted at one end of the pipeline 10 and propelled forwards, typically by the force of the fluid travelling through the pipeline. The design of the gauge plate 3 is such that the use of external propulsion means has no detrimental effect on the detection means 7. In one preferred embodiment the detection means is formed by an electrically or optically conducting material. For example, the detection means may comprise an electrical circuit which is formed by tape 3, such as fracture detection or glass break tape. The tape 4 forms a closed circuit when the plate 3 is intact, the signal from this circuit being transmitted to a remote centre from the transmitter 4. However, when the apparatus 1 meets a fault one or more of the slits in the gauge plate 3 bends and results in the circuit being broken. The resultant interruption or alteration of the signal can be monitored by the remote centre and the location of the fault can be accurately determined. In a second preferred embodiment the detection means is mechanical. For example, a strain gauge may be incorporated into the gauge plate to detect physical defects in the pipeline. The apparatus may also be provided with data storage means for recording information during a sweep through the pipeline. The information so recorded can be analysed once the sweep has been completed. This is useful as a back up mechanism if for some reason communication between the detection means and transmission means or remote centre is interrupted or detrimentally affected. As the apparatus has storage means, any information gained during a sweep will not be lost if the transmitting function of the pig is detrimentally affected. It will be appreciated, that as one sweep can take a considerable length of time, particularly in long, subsea pipelines, this back-up mechanism ensures that time and expenditure has not been wasted on a run if the transmitting function of the apparatus is affected. The gauge plate may also be adapted to allow for the measurement of subtle defects such as curvature of the pipeline. The transmitting means which transmits the information regarding the physical condition of the pipeline to the remote centre, may be in the form of an acoustic, electro-magnetic, nucleonic or mechanical system, depending on the prevalent conditions in the pipeline and the operator's preference. An advantage of the present invention is that the pipeline pig can be inspected for damage without having to visually examine it. Therefore the physical condition of the pipeline can be monitored without having to retrieve the pig from the pipeline. A further advantage is that there is provided apparatus for detecting physical faults in a pipeline that can be operated from a remote location. A further advantage of the present invention is that any faults that are detected can be repaired within a short period of time and at considerably reduced cost. A yet further advantage of the present invention is that where the gauge plate is made from an elastomeric material, the gauge plate will return to its original shape after passing the defect in the pipeline and can therefore be used to indicate other faults further along the pipeline. The gauge plate may also be provided with a feedback mechanism such that the gauge plate on passing a fault can be reset to its original position allowing for the measurement of a multiple of faults. Further modifications and improvements may be added without departing from the scope of the invention herein intended.

Claims: Claims 1. Apparatus for determining the physical condition of a pipeline, wherein the apparatus comprises a gauge plate mounted on a mobile carrier, the gauge plate being provided with detection means for detecting deformation of the gauge plate resultant from physical defects in the pipeline, and the apparatus further comprising transmission means to indicate to a remote location the detection of the presence of physical defects . 2. Apparatus as claimed in Claim 1 wherein the mobile carrier is a pipeline pig. 3. Apparatus as claimed in any one of the preceding Claims wherein the detection means is a strain gauge. 4. Apparatus as claimed in any one of the preceding Claims wherein the detection means is in the form of a conductive element formed by an electrically or optically conductive material. 5. Apparatus as claimed in Claim 4 wherein the conductive element is applied to or mounted on the rear face of the gauge plate. 6. Apparatus as claimed in any one of the preceding Claims wherein the detection means is an electrical circuit formed by tape. 7. Apparatus as claimed in Claim 6 wherein the tape is fracture detection tape. 8. Apparatus as claimed in Claim 6 wherein the tape is glass break tape. 9. Apparatus as claimed in any one of Claims 6 to 8 wherein the tape is fixed to the plate such that a closed circuit is formed while the plate remains undamaged and an open circuit is formed when the plate becomes damaged. 10. Apparatus as claimed in any one of the preceding Claims wherein the transmission means is an acoustic system. 11. Apparatus as claimed in any one of Claims 1 to 9 wherein the transmission means is an electromagnetic system. 12. Apparatus as claimed in any one of Claims 1 to 9 wherein the transmission means is a nucleonic system. 13. Apparatus as Claimed in any one of Claims 1 to 9 wherein the transmission means is a mechanical system. 14. Apparatus as claimed in any one of the preceding Claims wherein the gauge plate is provided with a series of radial slits which divide the plate. 15. Apparatus as claimed in any one of the preceding Claims wherein the guage plate is made from an elastomeric material. 16. Apparatus as claimed in any one of the preceding Claims wherein the apparatus is propelled through the pipeline by pipeline fluid. 17. Apparatus as claimed in any one of the preceding Claims wherein the carrier is adapted to store data. 18. A method of determining the physical condition of a pipeline comprising the steps of: a) passing a carrier through the pipeline, the carrier comprising a gauge plate and detection means for detecting deformation of the gauge plate; and b) transmitting a signal to a remote location upon said detection by the detection means.

Inventors: YATES ANTHONY, YATES, ANTHONY
Applicants: COPIPE SYSTEMS LIMITED, YATES ANTHONY, YATES, ANTHONY
Application year: 2000
Main classification: B08B
IPC codes: G01B3