METHOD FOR LAUNCHING A CLEANING ELEMENT

Abstract

A deformable cleaning element is encased within soluble packaging to maintain deformation. The deformed cleaning element is launched into the bore of a drill pipe/conduit or tubular. Contact with fluids within the bore dissolves the soluble packaging allowing the cleaning element to expand to its original shape.

Claims

1. Apparatus for deforming a cleaning element for launching it into a pipe, the apparatus comprising: a device for mechanically deforming the cleaning element; and soluble packaging that encases the deformed cleaning element to maintain deformation.

2. Apparatus as claimed in claim 1, wherein the soluble packaging is in the form of a film.

3. Apparatus as claimed in claim 1, wherein the soluble packaging is in the form of a rigid container.

4. Apparatus as claimed in claim 1, wherein the solubility of the soluble packaging is optimised for the temperature of the well fluid.

5. Apparatus as claimed in claim 1, wherein the deformed cleaning element is sealed within a watertight container.

6. Apparatus as claimed in claim 1, wherein the watertight container sealing the deformed cleaning element comprises at least one seal and/or at least one endcap.

7. Apparatus as claimed in claim 5, wherein the watertight container contains a moisture absorbing device.

8. Apparatus as claimed in claim 7, wherein the moisture absorbing device is integrated within the watertight container.

9. A cleaning element for cleaning a pipe, the cleaning element comprising a resilient material adapted to be deformed from an expanded resting configuration having a first dimension to a second deformed configuration having a second dimension smaller than the first dimension, the cleaning element being encased with a packaging to maintain deformation of the cleaning element in the deformed configuration, wherein the packaging is soluble.

10. A cleaning element as claimed in claim 9, wherein the packaging is soluble in water.

11. A cleaning element as claimed in claim 9, wherein the packaging is soluble in drilling fluid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the accompanying drawings,

[0040] FIG. 1 is a schematic side view of a roller sequence in a packaging device compressing a cleaning element and wrapping it in a single roll of soluble film;

[0041] FIG. 2 is a schematic side view of a deformed cleaning element encased in soluble film after being compressed in the packaging device of FIG. 1;

[0042] FIG. 3 is a schematic side view of the deformed cleaning element encased in soluble film being launched into a tubular by dropping it into the bore;

[0043] FIG. 4 is a schematic side view of the FIG. 1 deformed cleaning element in situ within the bore, where one side of the element is in contact with fluid and the soluble packaging has dissolved;

[0044] FIG. 5 is a schematic side view of a deformed cleaning element wrapped in soluble film and disposed in a transportation container.

[0045] FIG. 6 is a schematic side view of a transportation container and launching apparatus used for transporting the FIG. 1 deformed cleaning element.

[0046] FIG. 7 is a schematic side view of the deformed cleaning element encased in both soluble film and rigid soluble packaging; and

[0047] FIG. 8 is a schematic view of a deformed cleaning element encased in a rigid soluble container.

DESCRIPTION OF ONE OR MORE EXAMPLES OF THE INVENTION

[0048] FIG. 1 shows a schematic side view of one possible packaging device 5 used to compress a cleaning element 10 into an ovoid shape having approximate symmetry around the long axis, before wrapping the film 12 around the compressed cleaning element 10. The cleaning element 10 optionally comprises a spherical ball of resilient material such as rubber having a larger outer diameter than the pipe in which it is to be used. The ball 10 is encased within flexible soluble film 12, which is wrapped around the outer surface of the ball 10 by the packaging device 5. The film 12 in this example comprises a polyvinyl alcohol material.

[0049] The packaging device 5 comprises a throat 17t having sequence of vertically separated pairs of mechanical rollers 17 which are optionally mounted on horizontal axles and are mutually parallel, and in which each pair of rollers 17 are spaced from one another laterally in the same horizontal plane. The lateral spacing between each pair of rollers 17 is optionally not consistent between different pairs, and the rollers 17u in the pairs at the upper end of the throat (closer to the open end) are optionally spaced apart from one another by a larger spacing than the rollers in the pairs 171 at the lower end of the sequence. The spacing between adjacent pairs gradually decreases along the sequence. The throat 17t is arranged vertically in this example, with the opening of the throat 17t at the upper end, and this helps to feed the cleaning element 10 into the throat 17t but this is not necessary in all examples.

[0050] The cleaning element 10 is passed through the throat 17t in the direction of the arrow A. This can be accomplished by a feed mechanism which pushes the cleaning element 10 through the throat 17t, or the rollers 17 can be driven in rotation in opposite directions around the axles, for example by pneumatic, hydraulic, or electric drivers, and can draw the cleaning element into the throat 17t. As the cleaning element 10 proceeds along the roller sequence in the throat 17t, the diameter of the cleaning element 10 is reduced as the distance between each roller in each sequential pair gradually decreases, thereby increasing the deformation of the cleaning element as it moves down the sequence of rollers lining the throat. Optionally also, the diameter of the rollers 17 changes, e.g. increases along the sequence. Therefore, as the cleaning element 10 moves down the sequence of rollers 17 in the deformation apparatus 5, the cleaning element 10 is deformed from its initial generally spherical shape shown at the upper end of the sequence, to the ellipsoid or ovoid shape shown at the lower end of the sequence.

[0051] Optionally, the packaging device 5 incorporates a wrapping device. The deformed cleaning element 10 is optionally also wrapped in the throat 17t of the packaging device 5 by at least one layer of soluble film 18 as the deformed cleaning element 10 is passed between a pair of narrowly spaced rollers 17w located at an optional wrapping device optionally at the lower end of the sequence in this example, but could be arranged at any location in the sequence, optionally after the cleaning element has started to deform at least partially. The wrapping device comprises at least one roll of film 12 held on at least one spool 19 adjacent the rollers 17w.

[0052] As the deformed cleaning element 10 passes between the rollers 17w, the spool 19 unwinds a length of film 12 and encases the deformed ovoid cleaning element 10 in at least one layer of the soluble film 12. In this example, only one layer of soluble film 12 is wrapped around the deformed cleaning element 10, but in other examples, more than one layer of film can be wrapped at this stage. Optionally subsequent layers can be wrapped from the same roll of film, but also in other examples, additional sets of rollers 19 and additional rolls of soluble film 12 can be provided for the extra layers of film wrapped around the compressed cleaning element such that the deformed cleaning element 11 is encased in more than one layer of soluble film 12.

[0053] Optionally, the wrapping device also folds the layer of soluble film 12 around the compressed deformed cleaning element 10 while it is in the deformed configuration. Optionally the wrapping device incorporates a securing element which secures the soluble film around the deformed cleaning element 10 in order to maintain the deformed configuration of the cleaning element 10, and to resist radial expansion of the deformed cleaning element out of the ovoid configuration. Optionally the securing element seals the film around the compressed deformed cleaning element 10. Optionally, the sealing element comprises a heating element, which heat seals at least one seam of the film 12 to create a barrier around the cleaning element. Optionally, the sealing element hermetically seals the film 12 around the deformed cleaning element 10, and resists passage of air through the sealed film 12. However, in some other examples, the deformed cleaning element need not be hermetically sealed, and it is sufficient that, for example, a band of film 12 is wrapped around at least a portion of the outer circumference of the cleaning element in order to maintain at least some deformation of the cleaning element, sufficient to allow passage of the deformed cleaning element into the bore of the pipe to be cleaned.

[0054] While in the resting uncompressed configuration, the cleaning element 10 was substantially spherical (see initial sequence in FIG. 1), but it has been compressed into an ovoid configuration shown in FIG. 2, which is maintained by the wrapping of the flexible soluble film 12. The encasement by the flexible soluble film 12 maintains deformation of the cleaning element 10 in the ovoid configuration until the soluble film 12 comes into contact with fluid that is capable of dissolving the soluble film 12 as will be explained below.

[0055] FIG. 3 shows a side view of a deformed, encased cleaning element 10 in the ovoid configuration that has been generated by the packaging device 5 being launched into the box end 13 of a tubular T having an inner wall Tw to be cleaned. The element 10 is dropped into the box end 13 such that it is axially aligned with the bore 14 of the tubular T. This can optionally be accomplished by simply dropping the deformed encased cleaning element 10 into the wide diameter bore of the box end 13. Note that the outer diameter of the ovoid configuration of the cleaning element 10 is slightly narrower than the bore 14 of the tubular T, so held in the ovoid configuration by the film 12 can pass relatively easily into the bore 14 of the tubular T without requiring excessive force to deform the cleaning element 10 much further. Note that in certain examples of the invention, it is acceptable for the outer diameter of the cleaning element tend to be slightly more than the inner diameter of the bore 14 of the tubular T, and as long as the deformed encased cleaning element 10 can be dropped satisfactorily into the wide diameter of the box end 13, it can be flushed into the bore 14 by a fluid pressure differential.

[0056] Once the deformed encased cleaning element 10 has been flushed into the bore 14 by fluid F (which in this example is water), the fluid F within the bore 14 that contacts the film 12 on the outer surface of the deformed encased cleaning element 10 will start to dissolve the film 12 and reduce its integrity to the extent that it no longer maintains the deformed ovoid configuration, and eventually gives way to allow unrestrained radial expansion of the cleaning element 10 within the bore 14 under the force of its own natural resilience that was being restrained by the film 12 prior to loss of film integrity. FIG. 4 is a side view of the deformed cleaning element 10 encased in soluble film 12, in situ in a bore 14. The upper end of the deformed cleaning element 10 is in contact with the flushing fluid F and the soluble film 12 on the side of the deformed cleaning element 10 that is in contact with the fluid F has dissolved, and the upper end of the cleaning element 10 has resiliently expanded to fill the bore and press the outer diameter of the cleaning element 10 against the inner surface of the wall Tw of the tubular T. The resilience of the cleaning element 10 exert a radial force against the inner surface of the wall Tw, and as the cleaning element 10 travels axially within the bore 14 through the pressure of the flushing fluid F, the inner surface of the wall Tw is cleaned of debris.

[0057] Optionally, the deformed encased cleaning element 10 can be transported to the well within a transport container, which can optionally be sealed in order to avoid degradation of the soluble film 12 as a result of moisture ingress into the transport container. In FIG. 5, there is schematically shown one example of a transport container in the form of a plastic tube 20, which can optionally have removable end caps 21, which can be secured by threaded connections between the end caps 21 on the ends of the tube 20, or can be secured by a simple push fit. Optionally, the end caps 21 are sealed to avoid moisture ingress into the tube 20 during transport. The end caps 21 can be removed from the tube 20 before launching of the deformed encased cleaning element 10 into the well. Optionally, the tube 20 can include moisture absorbing device 22, optionally in the form of a silica pad, which binds moisture within the sealed tube 20, and reduces the risks of premature expansion of the cleaning element 10 by loss of integrity of the film 12 as a result of moisture ingress during transport.

[0058] FIG. 6 is a schematic side view of a launching apparatus 23. The apparatus 23 comprises a transportation container 20, within which the encased deformed cleaning element 10 is contained. The transportation container 20 optionally encloses the encased deformed cleaning element 10 by removable sealed endcaps 21 and also comprises a moisture absorbing device 22.

[0059] The launching apparatus 23 also includes a launcher 24 to launch the element 10 from the tube 20. The launcher 24 in this example takes the form of a small diameter tube, optionally having closed ends, that fits within the inner diameter of the tube 20 of the transportation container. By optionally removing the upper and lower endcaps 21 and pressing the closed ended launcher 24 into the bore of the tube 20 of the transportation container, the encased deformed cleaning element 10 is pushed out of the opposite end of the tube 20 and into the tubular. Since the film 12 restrains the deformed encased cleaning element 10 against radial expansion within the tube 20, the force required to push the cleaning element 10 from the tube 20 for launch is not excessive. Optionally, in this example, the tube 20 is formed of plastics material, which is resistant to the permeation of water, and which maintains a dry environment within the bore of the tube 20, to avoid premature activation of the cleaning element 10.

[0060] In a modified example, shown in FIG. 7, the deformed cleaning element 10 can be encased in soluble film 12 and then further encased in rigid soluble packaging 32. This element 10 can be launched into a tubular either using a launching device or by axially aligning the encased element with a bore and dropping the element into the bore. The rigid soluble packaging can optionally comprise a tube of sugar glass or polyvinyl alcohol. The rigid sugar glass or polyvinyl alcohol tube maintains a consistent outer diameter, which can be controlled to a dimension that is less than the inner diameter of the bore of the pipe to be cleaned. The rigid tube is dissolved in the same manner as the soluble film in the previous example by contact with the fluid within the bore of the pipe being cleaned. Once the structural integrity of the rigid soluble packaging and the wrapped film 12 has been degraded to a sufficient extent, the cleaning element 10 expands radially to fill the bore as previously described, and is flushed down the bore by a pressure differential in the fluid.

[0061] In a further modified example, FIG. 8 shows a schematic side view of a deformed cleaning element 30 encased within a rigid soluble housing 32. The encasement maintains deformation of the cleaning element 30 until the rigid soluble housing 32 comes into contact with fluid. The rigid soluble packaging can optionally comprise a generally tubular structure of sugar glass or polyvinyl alcohol. The rigid sugar glass or polyvinyl alcohol housing 32 maintains a consistent outer diameter, which can be controlled to a dimension that is less than the inner diameter of the bore of the pipe to be cleaned. The rigid soluble housing 32 is dissolved in the same manner as the soluble film in the previous example by the fluid within the bore of the pipe being cleaned. Once the structural integrity of the rigid soluble housing 32 has been degraded by the fluid in the bore to a sufficient extent, the cleaning element 30 expands radially to fill the bore as previously described, and is flushed down the bore in its expanded state by pressure differential in the fluid across the cleaning element 30.

[0062] Optionally, in this example, the cleaning element 30 can be compressed into the deformed configuration before application of the housing 32. Optionally, the housing 32 can be pre-formed in the tubular shape, but in this example, the cleaning element is optionally compressed into the deformed configuration by a cage or similar structure which surrounds the cleaning element 30 on some of its external surface, but not all of it, and maintains the deformed configuration while the housing is formed around the external surface of the deformed cleaning element 30. This can optionally be done in some examples by liquefying material forming the housing, and pouring or spraying the liquefied material onto the deformed cleaning element held by the cage. In some examples, the liquefied material can comprise polyvinyl alcohol, or sugar glass, which can be poured in liquid form over the caged compressed cleaning element and can be left to set into a solid state in order to constrain the deformed configuration of the cleaning element 30 and resist its radial expansion. Optionally, the cage can be removed, leaving the set housing 32 in place. Thus, the housing 32 and deformed compressed cleaning element 30 can be launched into the bore of the pipe, which is wider than the outer diameter of the tubular housing 32, and the resilient cleaning element 30 can expand radially within the bore of the pipe as previously described upon contact with fluid within the bore.

[0063] Further modifications and improvements may be made to the embodiments hereinbefore described without departing from the scope of the invention.