Technical field

The present invention relates to deploying flexible elongate members in water pipelines.

Background and prior art

Pipelines are commonly employed for transmitting fluid, such as water in a domestic water supply network. From time to time, it can be desirable to perform an inspection or survey of an underground water pipeline.

Problems in surveys include: undesired dislodging of rust, scale, or other build-ups of solids material from a wall of the pipeline where doing so may contaminate the water; and insufficient access to sections of the pipeline that may be obstructed by material on the interior wall of the pipeline.

Summary

The inventors have identified a need for solutions that better address the above problems, and an aim of the invention in general is to obviate or at least mitigate one or more drawbacks of prior art.

According to a first aspect of the invention, there is provided apparatus configured to be deployed inside an underground water pipeline, the apparatus comprising: a flexible elongate member; and a block of ice which is coupled to the flexible elongate member.

Preferably, the block of ice is disposed or contained in a structure, e.g. a containing structure, which is coupled to the flexible elongate member. The structure may have one or more holes or apertures for letting melt water out of the structure into the pipeline. The structure may be flexible for contracting around the block of ice upon melting. The structure may comprise a balloon or a bag.

The structure typically comprises walling of flexible material. The flexible material may comprise resilient or elastic material. The resilient or elastic material may be rubber, or comprise another suitable elastomer material. The walling preferably forms a thin membrane around the block of ice. The flexible elongate member typically comprises a rope or a cable, e.g. wireline, slickline, or similar. The elongate member may comprise a flexible rod.

The flexible elongate member may comprise an optical fibre. The optical fibre may be an optical sensing fibre for sensing one or more properties of contents of the pipeline in proximity to the fibre.

The optical sensing fibre may be configured to detect one or more temperatures of contents of the pipeline at a plurality of detection locations along the fibre.

According to a second aspect of the invention, there is provided a method of deploying a flexible elongate member, the method comprising the steps of: providing a block of ice which is coupled to the flexible elongate member; locating the block of ice inside a pipeline, the pipeline transmitting water; urging the block of ice along the inside of the pipeline, to position the flexible elongate member.

The method may further comprise applying a pressure in the pipeline to urge the block of ice along the inside of the pipeline. The pressure applied may be obtained by increasing a pressure upstream.

The method may include inserting the block of ice through a side entrance in the pipeline line wall. The method may include unspooling the flexible elongate member from a storage drum at surface, e.g. conveniently above ground.

The method may be a method of deploying the flexible elongate member in a survey or inspection of a pipeline.

The pipeline may have internal restrictions or deposits of material or corrosion on the internal wall of the pipeline. The method may include allowing the block of ice to melt to reduce in size to allow passage through at least one restriction in the pipeline. The flexible elongate member may be deployed in at least one horizontal or near-horizontal section of the pipeline.

In another aspect, there is provided apparatus configured to be deployed inside a pipeline, the apparatus comprising: a flexible elongate member; and a block of frozen liquid which is coupled to the flexible elongate member. The liquid may be or comprise water. The frozen liquid may comprise ice. In yet another aspect, there is provided a method of deploying a flexible elongate member, the method comprising the steps of: providing a block of frozen liquid which is coupled to the flexible elongate member; locating the block of frozen liquid inside a pipeline, the pipeline transmitting fluid; urging the block along the inside of the pipeline, to position the flexible elongate member. The liquid may be or comprise water. The frozen liquid may comprise ice. The pipeline may transmit water.

Any of the above aspects may further comprise features as described in relation to any other aspect wherever described herein.

Various advantages will be apparent from the application throughout.

Drawings and specific description

The various aspects above will now be described further, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a representation of apparatus to be deployed inside an underground water pipeline;

Figure 2 is a sectional representation of the apparatus of Figure 1 ; and

Figures 3A and 3B are schematic representations of the apparatus, in smaller scale, in use, at different times during deployment.

Referring first to Figures 1 and 2, apparatus 1 includes a flexible elongate member in the form of a rope 2 and a block of ice 3. The block of ice 3 is contained in a containing structure in the form of flexible balloon 4. The balloon 4 has apertures 5 that penetrate through flexible walling 6 of the balloon 4.

The apparatus 1 is configured to be deployed inside a water pipeline, as will be described further below. The block of ice can then be located in the pipeline and urged along the pipeline by applied pressure to bring the rope to the desired position. The use of the block of ice can be advantageous because the ice when located in the pipeline melts, allowing it to adapt its size to pass through restrictions. The melt water from the ice is advantageously clean, thereby avoiding contamination of the water being transmitted and supplied by the pipeline. The material of the walling is flexible and comprises resilient rubber material. To produce the block of ice, the containing balloon 4 is filled with water which is then frozen, e.g. by locating it in a freezer chamber. The walling 6 of the balloon 4 expands upon filling and to the volume change of the water as it freezes. A fill tube 8 is provided for filling water into the interior of the balloon 4.

In an alternative, a block of ice is formed separately, then flexible walling is fitted around the block to form the containing structure.

The balloon 4 in the present example is connected to an end portion 2e of the rope. The end portion 2e of the rope 2 is provided with a connector 7 which connects the balloon 4 securely to the rope 2.

The rope 2 in this example has an optical fibre 9 extending along the rope 2. The optical fibre 9 is usable for communication with sensors in different locations along the fibre. In one variant, the optical fibre 9 is an optical sensing fibre for detecting temperature or for detecting acoustic waves in the pipeline. The optical temperature sensing fibre can comprise gratings to allow temperature to be detected at several discrete detection locations along the fibre.

Turning now to additionally refer to Figures 3A and 3B, a system 100 including the apparatus 1 is depicted. The apparatus is being deployed in a section of a water pipeline 104 which is buried under the ground 102. The block of ice 3 in the balloon 4 is located inside the pipeline 104. The rope 2 is spooled out from storage drum 110. The pipeline 104 contains a flow of water, which is being transmitted through the pipeline 104 under pressure differential P1 greater than P2. The block of ice 3 is located in the water in the pipeline 104. The block of ice 103 is urged along the pipeline by the flow of water.

The water in the pipeline 104 exerts at least one component of force against the balloon and the block of ice to urge the apparatus along the pipeline 104. The rope 2 is preferably buoyant in the water to help to keep the rope away from the lower side of the pipeline 104.

In Figure 3A, at an early point in time, the balloon 4 containing the block of ice 3 has a large diameter d1. The upstream pressure P1 urges the block of ice 3 along the pipeline in the direction of the arrow F. The rope 2 simultaneously is moved along the pipeline into desired position. The rope 2 spools out as it advances along the pipeline 104 along with the block of ice 3. In Figure 3B, at a later point in time, the block of ice 3 has partially melted due to exposure to temperature of contents of the pipe 104 well above the freezing temperature. The block of ice 30 has therefore reduced in size, and the melt water from the ice block escapes out of the apertures 5 of the balloon 4 into the flow of water in the pipeline.

The walling of the balloon 4 contracts around the solid block of ice, and the balloon 4 containing the block of ice 3 obtains a much smaller diameter d2. The reduction in diameter from d1 to d2, makes it possible for the ice block 3 and rope 2 to go through the restriction 108 in the pipe, upon further travel along the pipeline in the flow. With the larger diameter d1 , the ice block would be too big to pass through the restriction 108. This facilitates deployment of the rope in pipes that suffer from restrictions 108 and deposits 107. Furthermore, if encountering a restriction during a survey of the pipeline, it is merely a matter of waiting until the ice block has reduced to an appropriate size before it then can progress onward along the pipeline 104. It is not necessary to raise pressure in the pipeline or apply high force against deposits or nodules to drive the rope further into the pipe. The solution is therefore gentler on deposits and structure on the wall of the pipe, and can facilitate performing a survey while keeping the interior intact. This can reduce risk of contamination.

In other variants, other flexible elongate members are used and deployed using a block of ice in similar manner.

In yet other variants, equipment or instruments, such as one or more sensors and tools, are carried into the pipeline on the flexible elongate member. Such equipment or instruments can facilitate performing a survey or inspection of the pipeline, e.g. to detect a presence or location of a leak.

Although the block of ice is contained in a containing structure in the examples above, one can appreciate that the containing structure might not necessarily be required, and could be connected to the rope by other means. The block of ice may also have other forms, e.g. may be ring-shaped and fitted around a core which in turn is connected to the rope.

In any of the above examples, a block of material may be provided instead of the block of ice. This block of material may similarly reduce in diametric size during travel along the pipeline by exposure to the prevailing conditions inside the pipeline. The block of material may be a block of frozen material that may reduce in diametric size by melting. By sufficient reduction in size it may pass through restrictions which otherwise may not be possible.