Technical Field
[0001] The present invention relates to a brush assembly for performing a cleaning and/or
brushing operation in a casing downhole, the brush assembly having a longitudinal
axis and comprising at least one brushing element. The brushing element comprises
a centre part and a plurality of arms.
Background
[0002] In a casing downhole, scales may be formed in the well fluid and precipitate onto
the sides of the casing wall or onto other elements comprised in a completion, such
as a valve. Such scales are very rigid and stick easily to the casing wall or valve,
and are thus very difficult to remove without damaging the valve or weakening the
wall.
[0003] Prior art cleaning tools have individual wires fastened to the side of the tool or
a rail in the tool. However, the wires are often too soft to be able to clean scales
off a valve and/or of the sides of a casing wall.
[0004] Furthermore, the brushes often get worn fast. When the brushes get worn, they lose
their brushing effect and need to be replaced or, in some cases, the entire cleaning
tool needs to be substituted by a new tool. Furthermore, replacement of the brushes
in the prior art solutions are very cumbersome.
[0005] Also, the prior art cleaning tools, and especially the brushing elements, are rather
complex, and they are thus not easy to manufacture.
[0006] US 2 517 017, which is considered as the closest prior art, discloses a brush assembly according
to the preamble of claim 1.
Description of the Invention
[0007] It is an object of the present invention to wholly or partly overcome the above disadvantages
and drawbacks of the prior art and to provide an improved cleaning tool able to remove
scales from the inside of a casing, a valve, a sleeve, etc. substantially without
damaging this object.
[0008] The above objects, together with numerous other objects, advantages, and features,
which will become evident from the below description, are accomplished by a solution
in accordance with the present invention by a brush assembly for performing a cleaning
and/or brushing operation in a casing downhole, the brush assembly having a longitudinal
axis and comprising:
- at least one brushing element comprising:
- a centre part, and
- a plurality of arms,
wherein the arms have a rectangular configuration when seen in cross-section.
[0009] A cleaning tool is obtained in which the brushes are strong enough to brush the interior
of a casing downhole, cleaning it free off rigid debris and other precipitated materials,
such as scales and the like.
[0010] Furthermore, the rectangular cross-sectional configuration of the arm may have two
first opposing sides being longer than two second opposing sides.
[0011] By having two first opposing sides longer than two second opposing sides, the arm
is able to bend easier in one direction than in another direction, thus making the
arm more flexible in one direction and more rigid in the other direction.
[0012] The centre part may be a longitudinal element, a winded part, or a disc.
[0013] In addition, the arms may extend through the centre part, be securely connected to
the centre part, or the arms and the centre part is formed as one element.
[0014] In one embodiment, the brushing element may be made from a sheet element.
[0015] Furthermore, a cleaning tool is obtained which is easy to manufacture and which facilitates
maintenance and replacements of brushing elements.
[0016] The sheet element may be made of metal or a reinforced composite material. The metal
may e.g. be spring steel.
[0017] Spring steel is extremely stress resistant and has an inherent flexibility, which
allows the arms of the brushing element to return to their original shape despite
significant bending or twisting.
[0018] In one embodiment, the spring steel may comprise 0.50%-2.50% silicon, 0.20%-2.50%
manganese, and 0.02%-1.50% carbon.
[0019] The arms of the brushing element may extend radially from the centre part and they
may be distributed around the centre part with an even distance and/or an uneven distance
between them. The arms may have a length and a width.
[0020] In one embodiment, part of the arms may be twisted around their length in an angle
θ. Hereby, the arm forms a tapered point end. The angle θ may be between 0-85°, preferable
between 20-65°, more preferably between 30-60°.
[0021] By twisting the arms around the length, a second part of the arm is given an angle
θ in relation to the other first part of the arm. In this way, the second part of
the arm is made flexible in a direction angled by the angle θ in relation to the first
part.
[0022] When the part of the arm is twisted in angle θ, the arm does not substantially damage
the inside wall of the casing or the valve since the arm is able to bend away from
the direction of rotation. If the arm is not twisted, it can only bend in the direction
of rotation which will not happen or in a direction perpendicular thereto. By twisting
the arm, it is easier for the arm to bend when operating the tool.
[0023] In another embodiment, a second part of the arm furthest away from the centre part
is twisted.
[0024] In addition, the second part is 10-90% of the length of the arm, preferably 30-70%
of the length of the arm, and more preferably 40-60% of the length of the arm.
[0025] The thickness of the sheet element may be between 0.2 and 3.0 mm.
[0026] The brushing element may be arranged on a shaft and the centre part of the brushing
element may comprise locking means adapted to engage with corresponding locking means
of the shaft.
[0027] The purpose of equipping the brushing element with locking means is to hinder the
brushing element from rotating around the shaft.
[0028] In one embodiment, a plurality of brushing elements may be arranged in succession
along the longitudinal axis of the brush assembly, which makes it possible to clean
and brush a greater area.
[0029] The brushing elements may be spaced apart by distance bushes.
[0030] Moreover, the lengths of the arms of the brushing elements may be substantially identical
or the arms of the brushing elements may have different lengths.
[0031] In one embodiment, the length of the arms near a front end of the brush assembly
is shorter than the length of the arms of the subsequent brushing elements. The object
to be cleaned may thus be cleaned very gently, as the shorter arms near the front
end rip up the surface of the elements to be removed before they are removed by the
subsequent, longer arms.
[0032] The brush assembly may comprise a first end piece arranged at the front end of the
assembly and a second end piece arranged at a back end of the assembly. In one embodiment,
the second end piece may be adapted to engage with a rotatable element, allowing the
brushing element to be rotated.
[0033] The invention also relates to a brushing element for use in a brush assembly as described
above and to use of such a brush assembly for cleaning or brushing a variety of different
objects downhole.
[0034] In addition, the invention relates to a downhole tool comprising one or more brush
assemblies as described above. The downhole tool may also comprise an anchor section
for anchoring the tool in a position downhole, e.g. against the inside wall of a casing.
[0035] Finally, the invention also relates to a downhole system comprising such a downhole
tool and a driving unit, such as a downhole tractor.
Brief Description of the Drawings
[0036] The invention and its many advantages will be described in more detail below with
reference to the accompanying schematic drawings, which for the purpose of illustration
show some non-limiting embodiments and in which
Fig. 1 shows a brushing element according to the present invention,
Fig. 2 shows an exploded view of the brush assembly in perspective,
Fig. 3 shows a cross-sectional view of the brush assembly along the longitudinal extension
of the assembly,
Fig. 4 shows a brush assembly with a spindle providing rotation and a translating
movement of the brush assembly,
Fig. 5 shows a downhole tool comprising a brush assembly,
Fig. 6 shows another embodiment of the brushing element according to the invention,
and
Fig. 7 shows the arm when twisted in angle.
[0037] All the figures are highly schematic and not necessarily to scale, and they show
only those parts which are necessary in order to elucidate the invention, other parts
being omitted or merely suggested.
Detailed description of the invention
[0038] The invention relates to a brush assembly 1 for removing scales from e.g. a valve,
a casing wall, or a sleeve and for cleaning the openings in a perforated section of
the casing. The brush assembly 1 comprises at least one brushing element 2 as shown
in Fig. 1. The brushing element 2 is here a plate-shaped element 18, where the brushes
are created when the element is cut out from a metal plate or sheet. The brushing
element 2 is cut into the shape of a flower or a sun, the flower petals or sunbeams
constituting the arms 4 of the brush.
[0039] As shown in Fig. 2, the brush assembly 1 may comprise several brushing elements 2
spaced apart by a distance bush 10. The brushing elements 2 and the distance bushes
10 are arranged on a common shaft 7 and are held together by a first 12 and a second
end piece 13. Each distance bush 10 is in the form of a ring. The thickness of the
distance bushes 10 may vary along the longitudinal axis of the brush assembly 1.
[0040] When the arms and the centre part is formed as one element, such as the brushing
element 2 being cut from a single metal sheet, the arms 4 of the brush assembly 1
have been made substantially more rigid than in prior art solutions. During a cleaning
operation, the arms 4 may be worn out, or damaged. When the brushing element 2 is
manufactured in one piece, the brush assembly may be easily repaired in that damaged
arms 4 may be replaced quickly by simply replacing the brushing element. Furthermore,
the brushing element 2 is easy to manufacture, avoiding additional mounting processes
for fastening the arms in the centre part 3.
[0041] In Fig. 1, the arms 4 have both a tapering part and a straight part. In Fig. 6, the
tapering part is much smaller so that the arm is substantially straight.
[0042] In the drawings, the brush assembly 1 is shown having seven brushing elements 2;
however, in another embodiment, it may comprise as few as one or even more than seven
brushing elements.
[0043] Even though the centre part 3 is shown in the form of a disc 18, the centre part
may have a variety of shapes, being a longitudinal element, a winded part, or the
like shape. The arms may also extend through the centre part, or be securely connected
to the centre part. By securely connected is meant any form of fastening, such as
by means of welding, glue, screws, rivets or the like fastening means.
[0044] The brushing elements 2 are provided with locking means 8 for hindering the elements
from rotating around the shaft 7. The locking means 8 may be indentations 19 matching
projections 20 on the shaft 7, preventing the brushing element 2 from rotating. The
indentations 19 and projections 20 may have any suitable form and, in another embodiment,
the locking means may be provided with projections matching indentations in the shaft
7 instead.
[0045] The brush assembly 1 may comprise a rotatable element 15, such as a spindle 21 and
a connecting element (not shown) as shown in Fig. 4. The spindle 21 may either slide
in relation to the connecting element, so that the spindle rotates and the connecting
element is fixed, or the connecting element may slide in relation to spindle, so that
the connecting element rotates and the spindle is fixed. The shaft 7 or the second
end piece 13 is connected with the rotating part, whether this is the connecting element
or the spindle 21. Thus, the brushing elements 2 can be moved back and forth while
rotating in order to remove scales from e.g. a valve. The spindle 21 may have any
suitable pattern 22 in order to engage the connecting element and provide rotation.
The spindle is shown as a spindle able to return without having to change the direction
of rotation. In another embodiment, the rotatable element 15 may be a shaft rotated
by means of hydraulics, pneumatics, an electronic motor, or the like.
[0046] When the brush assembly 1 is provided with several brushing elements 2, the length
of the arms 4 may differ between the brushing elements. Accordingly, the arms 4 of
the first brushing element 2 or the first couple of brushing elements situated in
the front end of the brush assembly 1, i.e. the end of the assembly first encountering
the object to be cleaned, may be shorter than the arms of the subsequent brushing
element or elements. Similarly, the arms 4 of these brushing elements 2 may again
be shorter than the arms of the subsequent brushing element or elements.
[0047] In Fig. 1, the brushing element 2 has 20 arms 4 extending radially outwards and the
arms are spaced along the periphery of the centre part 3 at an equal distance. However,
the arms 4 may also be spaced at an uneven distance. Each arm 4 is rectangular in
shape and has a width w and a length L and a thickness which is less than the width,
which again is less than the length. In this embodiment, the arms 4 of all the brushing
elements 2 have substantially the same thickness; however, they may also have different
thicknesses. The arms 4 of the first brushing element 2 may e.g. be thinner than the
arms of the subsequent brushing element or brushing elements. The arms 4 may have
a thickness of 0.2-3.0 mm, preferably 0.3-2.0 mm, and more preferably 0.4-1.0 mm.
[0048] The sheet or plate-shaped element 18 from which the brushing element 2 is manufactured
may made of any substantially rigid material having the flexibility necessary for
the brush to remove the scales without damaging the object to be cleaned.
[0049] The sheet or plate-shaped element 18 may thus be made of a metal sheet or plate or
a reinforced composite material. If metal is used, spring steel is advantageous as
it is both stress resistant and flexible enough to be able to return to its original
shape despite significant bending and twisting. The spring steel may comprise 0.50%-2.50%
silicon, 0.20%-2.50% manganese, and 0.02%-1.50% carbon. The metal sheet may also be
made of austenitic stainless steel.
[0050] In Fig. 1, the brushing element 2 has twenty straight arms 4. Each arm 4 may be twisted
in order to provide flexibility to the arm in two directions. The arms 4 may be twisted
around their lengths L or have a bended or corrugated shape when seen from one side
or in cross-section along the length.
[0051] In one embodiment, each arm 4 may be partly twisted so that a first part 23 of the
arm closest to the centre part 3 is maintained in the same plane 25 as the original
sheet element from which it was made, whereas a second part 24 of the arm is twisted.
This is illustrated in Fig. 6. The upper plane 26 of the twisted second part 24 is
twisted at an angle θ of approximately 45° to the plane 25 of the first part 23, forming
a tapered point end 5. The angle θmay be between 0-85°, preferably between 20-65°,
more preferably between 30-60°.
[0052] In another embodiment, a second part of the arm furthest away from the centre part
is twisted. In addition, the second part is 10-90% of the length of the arm, preferably
30-70% of the length of the arm, and more preferably 40-60% of the length of the arm.
In Fig. 6, the second part is approximately 50% of the length of the arm so that the
twist is distributed along the middle 6 of the arm.
[0053] By twisting the arms around the length, the second part of the arm is made flexible
in a direction angled by the angle θ in relation to the upper plane 25 of the first
part. When the part of the arm is twisted, the arm does not substantially damage the
inside wall of the casing or the valve since the arm is able to bend away from the
direction of rotation. If the arm is not twisted, it can only bend in the direction
of rotation which will not occur or in a direction perpendicular thereto. By twisting
the arm, it is easier for the arm to bend when operating.
[0054] Fig. 5 shows a downhole tool 16 comprising a brush assembly 1. As shown, the tool
16 may also comprise an anchor section 17 which may be used to anchor the tool to
the inside wall of the casing before the cleaning operation with the brush assembly
1 begins.
[0055] The tool 16 may also have so-called no-gos (not shown), i.e. hindering devices arranged
outside the tool. The devices abut a restriction (not shown) or a bottleneck (not
shown) in the casing preventing the tool 16 from moving any further and the brush
assembly 1 is subsequently moved further into the casing in order to clean the casing
from within.
[0056] The brush assembly 1 can be used for cleaning a variety of different objects downhole.
Due to the stiffness and high yield strength of the brushing elements 2, the brush
assembly 1 is highly suitable for removing even very difficult elements from the object,
such as scales from a valve, without doing any essential damage to the valve preventing
it from functioning properly subsequently.
[0057] In the course of time, scales will inevitably be formed and precipitate, but the
well fluid may also comprise other elements, such as shavings or formation pieces
from a drilling process, which are very difficult to remove unless by means of a brush
assembly 1 according to the present invention.
[0058] By fluid or well fluid is meant any kind of fluid that may be present in oil or gas
wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By gas is
meant any kind of gas composition present in a well, completion, or open hole, and
by oil is meant any kind of oil composition, such as crude oil, an oil-containing
fluid, etc. Gas, oil, and water fluids may thus all comprise other elements or substances
than gas, oil, and/or water, respectively.
[0059] By a casing is meant all kinds of pipes, tubings, tubulars, liners, strings etc.
used downhole in relation to oil or natural gas production.
[0060] In the event that the brush assembly 1 or the tool 16 is not submergible all the
way into the casing, a downhole tractor can be used to push the tools all the way
into position in the well. A downhole tractor is any kind of driving tool capable
of pushing or pulling tools in a well downhole, such as a Well Tractor®.
1. A brushing element for brush assembly (1) for performing a cleaning and/or brushing
operation in a casing downhole, the brush assembly having a longitudinal axis,
the brushing element (2) made from a sheet element and comprising:
- a centre part (3), and
- a plurality of arms (4) each having a length (L) and a width (w),
wherein the arms have a rectangular configuration when seen in cross-section and
characterised in that the arms have a thickness which is less than the width, and the sheet element is
made of metal, such as spring steel.
2. A brushing element according to claim 1, wherein the centre part is a longitudinal
element, a winded part, or a disc.
3. A brushing element according to claim 1 or 2, wherein the arms extend through the
centre part, are securely connected to the centre part, or the arms and the centre
part is formed as one element.
4. A brushing element according to any of the preceding claims, wherein the arms extend
radially from the centre part.
5. A brushing element according to any of the preceding claims, wherein part of the arms
is twisted around their length in an angle (θ).
6. A brushing element according to claim 5, wherein the angle θ is between 0-85°, preferably
between 20-65°, more preferably between 30-60°
7. A brushing element accordlng to claim 5 or 6, wherein a second part (24) of the arm
furthest away from the centre part is twisted, and wherein the second part is 10-90%
of the length of the arm, preferably 30-70% of the length of the arm, and more preferably
40-60% of the length of the arm.
8. A brush assembly for performing a cleaning and/or brushing operation in a casing downhole,
comprising a brushing element according to any of claims 1-7.
9. A brush assembly according to claim 8 comprising a first end piece (12) arranged at
the front end of the assembly and a second end piece (13) arranged at a back end (14)
of the assembly, and wherein the second end piece is adapted to engage with a rotatable
element (15) allowing the brushing element to be rotated.
10. Use of a brush assembly according to any of the claims 8 to 9 for cleaning or brushing
a variety of different objects downhole.
11. A downhole tool (16) comprising a brush assembly according to any of the claims 8
to 9.
12. A downhole tool according to claim 11, further comprising an anchor section (17) for
anchoring the tool in a position downhole, e.g. against an inside wall of a casing.
13. A downhole system comprising a downhole tool according to any of claims 11 or 12 and
a driving unit, such as a downhole tractor.
1. Bürstelement für eine Bürstanordnung (1) zum Durchführen eines Säuberns und/oder Bürstens
in einer Verkleidung in einem Bohrloch, wobei die Bürstanordnung eine Längsachse aufweist,
wobei das Bürstelement (2), das aus einem Blattelement gemacht ist, umfasst:
- einen zentralen Teil (3), und
- mehrere Arme (4), von denen jeder eine Länge (L) und eine Breite (w) aufweist, wobei
die Arme eine rechtwinklige Konfiguration aufweisen, wenn sie im Querschnitt gesehen
werden, und dadurch gekennzeichnet, dass die Arme eine Dicke aufweisen, die geringer als die Breite ist, und das Blattelement
aus Metall ist, so wie Federstahl.
2. Bürstelement nach Anspruch 1, bei welchem der zentrale Teil ein längliches Element,
ein gewundenes Teil oder eine Scheibe ist.
3. Bürstelement nach einem der Ansprüche 1 oder 2, bei welchem die Arme sich durch den
zentralen Teil erstrecken, fest mit dem zentralen Teil verbunden sind oder die Arme
und der zentrale Teil als ein Element ausgebildet sind.
4. Bürstelement nach einem der vorstehenden Ansprüche, bei welchem die Arme sich radial
von dem zentralen Teil erstrecken.
5. Bürstelement nach einem der vorstehenden Ansprüche, bei welchem ein Teil der Arme
um ihre Länge in einem Winkel (·) gedreht sind.
6. Bürstelement nach Anspruch 5, bei welchem der Winkel · zwischen 0 und 85° beträgt,
vorzugsweise zwischen 20 und 65°, noch bevorzugter zwischen 30 und 60°.
7. Bürstelement nach einem der Ansprüche 5 oder 6, bei welchem ein zweiter Teil (24)
des Arms, der von dem zentralen Teil am Weitesten entfernt ist, gedreht ist, und wobei
der zweite Teil 10 - 90% der Länge des Arms beträgt, vorzugsweise 30 - 70% der Länge
des Arms, und noch bevorzugter 40 - 60% der Länge des Arms.
8. Bürstanordnung zum Durchführen von Säubern und/oder Bürsten in einer Verkleidung in
einem Bohrloch, umfassend ein Bürstelement nach einem der Ansprüche 1 - 7.
9. Bürstanordnung nach Anspruch 8, umfassend ein erstes Endstück (12), das an dem vorderen
Ende der Anordnung angeordnet ist, und ein zweites Endstück (13), das an einem hinteren
Ende (14) der Anordnung angeordnet ist, und wobei das zweite Endstück ausgestaltet
ist, mit einem drehbaren Element (15) in Eingriff zu kommen, was dem Bürstelement
gestattet, gedreht zu werden.
10. Verwendung einer Bürstanordnung gemäß einem der Ansprüche 8 bis 9 zum Säubern oder
Bürsten einer Vielfalt von unterschiedlichen Objekten in einem Bohrloch.
11. Bohrlochwerkzeug (16) umfassend eine Bürstanordnung gemäß einem der Ansprüche 8 bis
9.
12. Bohrlochwerkzeug nach Anspruch 11, des Weiteren umfassend einen Ankerabschnitt (17)
zum Ankern des Werkzeugs in einer Position in einem Bohrloch, z.B. gegen eine Innenwand
einer Verkleidung.
13. Bohrlochsystem umfassend ein Bohrlochwerkzeug nach einem der Ansprüche 11 oder 12
und eine Antriebseinheit, so wie eine Bohrlochzugmaschine.
1. Elément de brossage pour un ensemble de brosse (1) pour réaliser une opération de
nettoyage et/ou de brossage dans un coffrage de forage, l'ensemble de brosse ayant
un axe longitudinal, l'élément de brossage (2) étant fait d'un élément de tôle comprenant
:
une partie centrale (3), et
une pluralité de bras (4) ayant chacun une longueur (L) et une largeur (w), dans lequel
les bras ont une configuration rectangulaire quand ils sont vus en section transversale,
et caractérisé en ce que les bras ont une épaisseur qui est inférieure à la largeur, et l'élément de tôle
est fait de métal, comme un acier à ressorts.
2. Elément de brossage selon la revendication 1, dans lequel la partie centrale est un
élément longitudinal, une partie torsadée, ou un disque.
3. Elément de brossage selon la revendication 1 ou 2, dans lequel les bras s'étendent
à travers la partie centrale, sont fixés solidement sur la partie centrale, ou les
bras et la partie centrale sont formés comme un seul élément.
4. Elément de brossage selon l'une quelconque des revendications précédentes, dans lequel
les bras s'étendent radialement depuis la partie centrale.
5. Elément de brossage selon l'une quelconque des revendications précédentes, dans lequel
une partie des bras est tordue autour de leur longueur avec un angle (6).
6. Elément de brossage selon la revendication 5, dans lequel l'angle 6 est de 0-85°,
de préférence de 20-65°, plus préférablement de 30-60°.
7. Elément de brossage selon la revendication 5 ou 6, dans lequel une seconde partie
(24) du bras encore plus éloignée de la partie centrale est tordue, et dans lequel
la seconde partie est de 10-90% de la longueur du bras, de préférence 30-70% de la
longueur du bras, et plus préférablement 40-60% de la longueur du bras.
8. Ensemble de brossage pour réaliser une opération de nettoyage et/ou de brossage dans
un coffrage de forage, comprenant un élément de brossage selon l'une quelconque des
revendications 1-7.
9. Ensemble de brossage selon la revendication 8, comprenant une première pièce d'extrémité
(12) agencée au niveau de l'extrémité avant de l'assemblage et une seconde pièce d'extrémité
(13) agencée au niveau d'une extrémité arrière (14) de l'assemblage, et dans lequel
la seconde pièce d'extrémité est adaptée pour venir en prise avec un élément tournant
(15) permettant à l'élément de brossage d'être mis en rotation.
10. Utilisation d'un assemblage de brosse selon l'une quelconque des revendications 8
à 9 pour nettoyer ou brosser une variété d'objets différents dans un forage.
11. Outil de forage (16) comprenant un ensemble de brosse selon l'une quelconque des revendications
8 à 9.
12. Outil de forage selon la revendication 11, comprenant en outre une section d'ancrage
(17) pour ancrer l'outil dans une position dans le forage, par exemple contre une
paroi intérieure d'un coffrage.
13. Système de forage comprenant un outil de forage selon l'une quelconque des revendications
11 ou 12 et une unité d'entraînement, comme un tracteur de forage.