Sensor arrangement, underwater vehicle and method for underwater detection of a leak in fluid carrying body

#This application is a national stage application of International Application No. PCT/NL2018/050196, which was filed on Mar. 29, 2018, which claims priority to Netherlands Application Number 2018637 filed on Apr. 3, 2017, of which is incorporated by reference in its entirety.

#The present invention is directed at a sensor arrangement and a method for underwater detection of a leak in fluid carrying body.

#Although a leak in a container or in an industrial installation may reveal itself by leaving a trace, leaks in fluid conveying pipelines are many times difficult dependent on the circumstances. For example, big leaks may easily be detected by measuring a decreased output from a pipeline where it arrives, and may also directly reveal themselves by a spill at the location of the leak. Small leaks, however, are much more difficult to find. The trace of leaked fluid may be minimal such that it is easily overlooked. Moreover, a small leak may not be characterized by a noticeable pressure drop or decrease of output on the receiving side at the end of a pipeline. In particular if the leak occurs However, obviously even small leaks provide a burden on the environment dependent on the nature of fluid leaked, which therefore can be of great concern to the public and to the owner of the pipeline.

#The invention will further be elucidated by description of some specific embodiments thereof, making reference to the attached drawings. The detailed description provides examples of possible implementations of the invention, but is not to be regarded as describing the only embodiments falling under the scope. The scope of the invention is defined in the claims, and the description is to be regarded as illustrative without being restrictive on the invention. In the drawings:

#FIG. 1 schematically illustrates an underwater vehicle comprising a sensor arrangement in accordance with the present invention;

#FIG. 2 schematically illustrates a sensor arrangement in accordance with the present invention;

#FIG. 1 schematically illustrates an underwater vehicle 10. The underwater vehicle 10 may be an autonomous underwater vehicle (AUV), remotely operated vehicle (ROV) or a different type of vehicle that may be controlled or operated from a survey ship 50 at the surface. In the example of FIG. 1, the remotely operated vehicle 10 is connected to a survey ship by means of a wireline connection 20 comprising a plurality of optical fibers. The optical fibers in wireline connection 20 allow for the exchange of optical signals with the remotely operated vehicle 10. Optionally, additional signal transfer lines, such as electrical connections, may be comprised by the wireline connection 20 dependent on the type of remotely operated vehicle 10 and/or the requirements of the on-board equipment.

#A sensor arrangement 12 comprises a sensor support structure 13 and a mounting structure 11. The sensor arrangement 12 is mounted to the underwater vehicle 10 by means of the mounting structure 11. The sensor support structure 13 comprises a top face 15 and two side faces 16 and 17. The sensor support structure 13, on these faces 15, 16 and 17 comprises a grid of thermal sensors distributed across the surface of the faces 15, 16 and 17. The sensors are facing the pipeline 3. The pipeline 3 runs across the sea bed 5 between two different geographic locations. For example, the pipeline 3 may be transporting oil from a first location to a second location. The remotely operated vehicle 10 having mounted thereon the sensor arrangement 12, moves over the pipeline 3 accurately following the length of the pipeline for detecting any leaks therein. As an example, the pipeline 3 comprises a small leak 6 through which oil bubbles 7 escape, which are rising towards the surface of the sea. As may be appreciated, the sensor arrangement 12 is also suitable for detecting large oil spills, wherein large amounts of oil leak from the pipeline into the ambient water. However, in the present example a small leak 6 is depicted through which only bubbles 7 of oil are released is taken as example, because this type of oil spill is difficult to detect using different technologies.

#Using an underwater vehicle 10 in accordance with the present invention, having mounted thereon a sensor arrangement 12 in accordance with the present invention, the vehicle is moved above the pipeline 3 relative thereto. The plurality of thermal sensors is located on those side of the faces 15, 16 and 17 that are facing the pipeline 3. Any bubble 7 that hits or grazes a thermal sensor, changes the output signal of the thermal sensor enabling detection of a sudden temperature increase. As explained hereinabove, for bubbles of warm oil in the ambient sea water, the temperature increase is detected as a sharp peak in case it directly hits the thermal sensor. A somewhat less intense sharp peak is detected in case the bubble grazes the sensor.