Downhole tool for cleaning and collecting particles in a well

Abstract

The present invention relates to a downhole tool for cleaning one or more parts of a well used for the production of hydrocarbon-containing substances such as oil and / or gas, wherein the downhole tool has a longitudinal extension and comprises a motor electrically connected to an electrical cable such as a wireline; a pump driven by the motor and having an inlet and an outlet; a chamber having a chamber wall and being in fluid communication with the inlet; a removable filter part arranged in the chamber and provided with a plurality of filter openings, the filter part having an open end and a closed end, wherein the closed end is arranged closest to the pump; and a front end comprising at least one tool inlet connected to the open end of the filter part, the front end forming a conduit, so that fluid with particles or impurities is directed from the tool inlet into the filter part, and the fluid without particles and impurities may leave the filter part through filter openings and in through the pump inlet, wherein the removable filter part is designed as a stiff or rigid filter wall through which the filter openings extend.

Description

[0001] DOWNHOLE TOOL FOR CLEANING AND COLLECTING PARTICLES IN A WELL

[0002] Technical field

[0003] The present invention relates to a downhole tool for cleaning one or more parts of a well used for the production of hydrocarbon-containing substances such as oil and / or gas.

[0004] Background of the invention

[0005] Over the life of a well, it may become clogged with sand and other larger or smaller particles and impurities, requiring the well to be cleaned. Downhole tools for cleaning a well have a pump, which sucks the particle-containing fluid through an attached filter in the downhole tool and collects the particles in a collection chamber inside the downhole tool. In some wells, the volume of particles and impurities is so large that the volume capacity of the downhole tool collection chamber is insufficient to collect the entire volume in the chamber, requiring the downhole tool to be pulled out of the well and the chamber emptied before the downhole tool can be reinserted and the cleaning process resumed. To speed up emptying, so that the downhole tool may quickly resume the cleaning process, some downhole tools known in the art have a removable filter cloth or filter sock, which is removed and a new one inserted . The power consumption of the pump is often measured, so that when the pump requires excessive power for suction, this is an indicator that the chamber or filter is almost full. However, the replaceable filter cloth or filter sock has proven to be problematic as it twists and therefore does not fill completely before the pump's power consumption increases significantly, resulting in a halffilled downhole tool being pulled out of the well. A more efficient solution is therefore needed.

[0006] Brief summary of the invention

[0007] The object of the present invention is to provide a solution, in whole or in part, to the above disadvantages and weaknesses of the prior art. In particular, it is an object to provide an improved downhole tool for cleaning a well, capable of collecting larger amounts of impurities or particles in a fast and efficient manner.

[0008] The above objects and several other objects, advantages and features which will become apparent from the following description, are achieved with a solution according to the present invention by providing a downhole tool for cleaning one

[0009] P2888PC00 or more parts of a well used for the production of hydrocarbon-containing substances such as oil and / or gas, wherein the downhole tool has a longitudinal extension and comprises a motor electrically connected to an electrical cable, such as a wireline; a pump driven by the motor and having an inlet and an outlet; a chamber having a chamber wall and being in fluid communication with the inlet; a removable filter part arranged in the chamber and provided with a plurality of filter openings, the filter part having an open end and a closed end, wherein the closed end is arranged closest to the pump; and a front end comprising at least one tool inlet connected to the open end of the filter part, the front end forming a conduit, so that fluid with particles or impurities is directed from the tool inlet into the filter part, and the fluid without particles and impurities may leave the filter part through filter openings and in through the pump inlet, wherein the removable filter part is designed as a stiff or rigid filter wall through which the filter openings extend.

[0010] The downhole tool may also be a cleaning downhole tool.

[0011] Furthermore, the downhole tool may be a wireline downhole tool.

[0012] The removable filter part may further be more stiff or rigid than a sock made of fabric or similar.

[0013] The removable filter part may also be designed as a stiff or rigid wall, so that the filter part does not collapse when the pump stops sucking.

[0014] Moreover, the removable filter part may be mainly made of metal, such as made from a metal plate e.g. with punched or cut openings, or a metal mesh.

[0015] The removable filter part may also be mainly made of plastic.

[0016] In addition, the filter openings may have an extension perpendicular to the longitudinal direction of the downhole tool.

[0017] Each filter opening may further have an inlet and an outlet, so that the inlet of the filter opening is on the inside of the filter part and the outlet of the filter opening is on the outside of the filter part. The filter opening may have an extension, so that the inlet of the filter opening is arranged closer to the pump than to the front

[0018] P2888PC00 end, and the outlet of the filter opening is arranged closer to the front end than to the pump.

[0019] Furthermore, the removable filter part may have a Shore A hardness higher than 40.

[0020] The removable filter part may also have a Shore D hardness higher than 10.

[0021] Moreover, the removable filter part may be less flexible than fabric.

[0022] The removable filter part may additionally be detachably connected to the chamber wall or front end via, e.g., a thread.

[0023] The closed end of the filter part may further consist of an end wall extending perpendicular to the longitudinal direction of the downhole tool.

[0024] The front end may also be detachably connected to the chamber wall.

[0025] Additionally, the filter part may have a filter length, and the downhole tool may have an outer diameter, wherein the filter length is at least 4 times larger than the outer diameter, and preferably at least 6 times larger than the outer diameter.

[0026] The downhole tool may also comprise a control unit arranged between the cable head and the motor.

[0027] The motor may also be an electric motor.

[0028] Furthermore, the pump may suck fluid in through the tool inlet via the filter openings and in through the pump inlet.

[0029] Moreover, the filter wall may have a surface area, and the plurality of filter openings may cover at least 15% of the surface area, preferably 20% of the surface area, and more preferably at least 25% of the surface area.

[0030] In addition, the filter openings may have a diameter of at least 1 mm, preferably at least 2 mm, and more preferably more than 3 mm.

[0031] P2888PC00 The filter part may further comprise a filter cloth arranged on the inside or outside of the filter part.

[0032] Also, the filter wall between the filter openings may be impermeable.

[0033] Additionally, the removable filter part may be detachably connected to the chamber wall.

[0034] Furthermore, the front end may be detachably connected to the chamber wall for removing the filter part.

[0035] In addition, the removable filter part may be detachably connected to the front end via a thread.

[0036] Moreover, the chamber may be formed by the chamber wall, the front end and a face facing the pump and the removable filter part being detachably connected to the face.

[0037] Further, the chamber may be formed by the chamber wall, the front end and a face facing the pump and the removable filter part being detachably connected to the chamber.

[0038] Finally, the chamber may be closed towards the tool inlet. The valve may be a oneway valve such as flapper valve, a ball valve or a similar check valve.

[0039] Brief description of the drawings

[0040] The drawings only serve as explanation of the present invention and should in no way be considered as limiting to the description of the invention. It furthermore applies that shapes and sizes in the drawings of various parts are schematic and intended to provide a better understanding of the invention and should therefore not be used to specifically limit the shapes and sizes of various parts in the present application. Those skilled in this field will be able to select the possible shapes and sizes to implement the invention on the basis of the present application.

[0041] 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 :

[0042] P2888PC00 Fig. 1 shows a partial cross-section of a downhole tool of the present invention for collecting impurities and other particles in a well in a rigid filter, which can be easily removed and emptied before continuing the cleaning process,

[0043] Fig. 2 shows a filter part in perspective,

[0044] Fig. 3 shows a partial cross-section of another embodiment of a downhole tool, and

[0045] Fig. 4 shows a partial cross-section of a downhole tool in a clogged well.

[0046] 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.

[0047] With reference to the accompanying drawings, the present invention will be described in more detail in the following.

[0048] Detailed description of the invention

[0049] Fig. 1 shows a partial cross-section of a downhole tool 1 for cleaning one or more parts of a well used for the production of hydrocarbon-containing substances such as oil and / or gas. The downhole tool 1 has a longitudinal direction L and comprises a motor 2 electrically connected to an electric cable 18 such as a wireline. The downhole tool 1 is thus a cable downhole tool and / or a cleaning downhole tool. The downhole tool 1 comprises a pump 3 driven by the motor 2 and having an inlet 4 and an outlet 5; a chamber 6 having a chamber wall 17 and being in fluid communication with the inlet 4 of the pump 3; and a removable filter part 7 arranged in the chamber 6 for collecting impurities and other larger or smaller particles 22 (shown in Fig. 4). The filter part 7 is provided with a plurality of filter openings 8, the filter part 7 having an open end 11 and a closed end 12, the closed end 12 being arranged closest to the pump 3. The removable filter part 7 is designed as a stiff or rigid filter wall 15 through which the filter openings 8 extend. The downhole tool 1 further comprises a front end 9 furthest away from the cable 18 and comprising at least one tool inlet 10 fluidly connected to the open end 11 of the filter part 7, wherein the front end 9 forms a conduit 14, so that fluid with particles or impurities 22 is directed from the tool inlet 10 into the filter part 7, and the fluid without particles and impurities 22 may leave the filter part 7 through

[0050] P2888PC00 filter openings 8 and in through the inlet of the pump 3. The removable filter part 7 is designed as a stiff or rigid wall, so that the filter part 7 does not collapse when the pump 3 stops sucking, which has proven to work well, so that the filter part 7 is completely filled before the power consumption of the pump 3 increases so much that the operator believes that the filter part 7 is full and pulls the tool 1 out of the well. In prior art solutions with a flexible sock, the sock 'ties knots' when the pump is not sucking with even force or briefly stops and interrupts suction. This does not happen when the filter part 7 is designed as a stiff or rigid wall through which the filter openings 8 extend. This is because the removable filter part 7 is more rigid than a fabric sock or similar, so that it does not 'knot' or twist with varying suction power.

[0051] The removable filter part 7 is mainly made of metal such as a metal tube to which an end wall 21 is welded as shown in Fig. 3, and with through-holes forming the filter openings 8. The removable filter part 7 may also be moulded in plastic. The filter openings 8 have an extension perpendicular to the longitudinal direction L of the downhole tool 1, as shown in Fig. 1. This turns the direction of the fluid with impurities 90°, causing the fluid without impurities to flow out through the filter openings 8, while the impurities / particles 22 continue past the filter openings 8 and are collected inside the filter part 7. The filter wall 15 between the filter openings 8 is thus impermeable, so that the fluid flow is directed in through the filter openings 8.

[0052] In another embodiment, each filter opening 8 has an inlet and an outlet, so that the inlet of the filter opening 8 is on the inside of the filter part 7, and the outlet of the filter opening 8 is on the outside of the filter part 7. The filter opening 8 has an extension such that the inlet of the filter opening 8 is arranged closer to the pump 3 than to the front end 9, and the outlet of the filter opening 8 is arranged closer to the front end 9 than to the pump 3.

[0053] It is thus important that the filter part 7 has a certain rigidity, i.e. has an elasticity of more than 2.5 GPa, preferably more than 50 GPa. To withstand particles hitting the filter wall 15 without the filter openings 8 wearing and increasing significantly, the removable filter part 7 has a Shore D hardness higher than 10.

[0054] In Fig. 3, the removable filter part 7 is detachably connected to the chamber wall 17 via e.g. a thread 16, and in Fig. 1, the removable filter part 7 is detachably

[0055] P2888PC00 connected to the front end 9 via, e.g., a thread 16, so that the filter part 7 can easily be unscrewed from the downhole tool 1, emptied and quickly screwed back on, whereafter the downhole tool 1 is re-introduced into the well. As shown in Fig. 1, the front end 9 is similarly detachably connected to the chamber wall 17 via a thread 16B.

[0056] In Fig. 3, the removable filter part 7 is detachably connected to the chamber wall 17 and the chamber wall is connected to the front end. Thus, the front end 9 is detachably connected to the chamber wall for removing the filter part by first unscrewing the front end and the removable filter part 7. In Fig. 1, the removable filter part 7 and the front end are detached from the chamber wall first and the removable filter part 7 is detached from the front end. In Fig. 1, the removable filter part 7 is detachably connected to the front end via a thread 16. As shown in Fig. 1, the chamber is formed by the chamber wall 17, the front end 9 and a face 28 facing the pump, and even though not shown, the removable filter part 7 may be detachably connected to the face so that the front end is firstly detached and the removable filter part 7 is then detached from the face 28. The removable filter part 7 may also be freely arranged inside the chamber and removed by detaching the front end, in the form of a bull nose, from the chamber.

[0057] The removable filter part 7 may be a metal mesh closed in one end by an end part and open in the other end. The metal mesh may be wounded into the shape of a tube and held in place by a ring and the end part and then arranged inside the chamber and the bull nose or front end fastened to the chamber.

[0058] The filter part 7 has a filter length, and the downhole tool 1 has an outer diameter, wherein the filter length is at least 4 times larger than the outer diameter, preferably at least 6 times larger than the outer diameter. The downhole tool 1 further comprises a control unit 19 arranged between the cable head 23 and the motor 2 for converting signals and power sent down the cable 18. The motor 2 is an electric motor which rotates a shaft that drives the pump 3. The pump 3 sucks fluid in through the tool inlet 10 via the filter openings 8 and in through the inlet 4 of pump 3, out through the outlet 5 and back into the well.

[0059] The filter wall 15 has a surface area, and the plurality of filter openings 8 cover at least 1% of the surface area, preferably 5% of the surface area, and more preferably at least 10% of the surface area, depending on which

[0060] P2888PC00 impurities / particles 22 are to be collected in the well. The filter openings have a diameter of at least 1 mm, preferably at least 2 mm, and more preferably more than 3 mm. The downhole tool 1 may further comprise a filter cloth (not shown) arranged on the outside of the filter part 7, so that the filter part 7 keeps the filter cloth extended to prevent it from 'knotting' under varying pumping force, at the same time making the filter part 7 is easy to replace or empty. The filter cloth may be attached to the outside of the filter part 7, so that the filter cloth overlaps and covers the filter openings 8, and so that the filter cloth is included when the filter part 7 is removed from the chamber 6 at the surface.

[0061] The removable filter part may be mainly made of metal, such as made from a metal plate e.g. with punched or cut openings, or from a metal mesh.

[0062] In Fig. 2, the removable filter part 7 is made as a solid wall, such as a tube, with openings 8.

[0063] As shown in Fig. 1, the chamber is closed towards the tool inlet by means of a oneway valve 29. The valve 29 is a one-way valve such as flapper valve, a ball valve or a similar check valve.

[0064] Although the invention has been described above in connection with preferred embodiments of the invention, it will be evident to a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.

[0065] P2888PC00

Claims

9Claims1. A downhole tool (1) for cleaning one or more parts of a well used for the production of hydrocarbon-containing substances, such as oil and / or gas, wherein the downhole tool has a longitudinal extension (L) and comprises:- a motor (2) electrically connected to an electrical cable (18), such as a wireline,- a pump (3) driven by the motor and having an inlet (4) and an outlet (5),- a chamber (6) having a chamber wall (17) and being in fluid communication with the inlet,- a removable filter part (7) arranged in the chamber and provided with a plurality of filter openings (8), the filter part (7) having an open end (11) and a closed end (12), the closed end (12) being arranged closest to the pump, and- a front end (9) comprising at least one tool inlet (10) fluidly connected to the open end of the filter part, wherein the front end forms a conduit (14), so that fluid with particles or impurities is directed from the tool inlet into the filter part, and the fluid without particles and impurities (22) may leave the filter part through filter openings and in through the inlet of the pump, wherein the removable filter part is designed as a stiff filter wall (15) through which the filter openings extend.

2. A downhole tool according to claim 1, wherein the removable filter part is mainly made of metal.

3. A downhole tool according to claim 1 or 2, wherein the filter openings have an extension perpendicular to the longitudinal direction of the downhole tool.

4. A downhole tool according to claim 1 or 2, wherein the removable filter part has a Shore D hardness higher than 10.

5. A downhole tool according to any of the preceding claims, wherein the removable filter part is detachably connected to the chamber wall or front end via, e.g., a thread (16).

6. A downhole tool according to any of the preceding claims, wherein the closed end of the filter part is constituted by an end wall (21) extending perpendicular to the longitudinal direction of the downhole tool.P2888PC007. A downhole tool according to any of the preceding claims, wherein the filter part has a filter length, and the downhole tool has an outer diameter, wherein the filter length is at least 4 times larger than the outer diameter, preferably at least 6 times larger than the outer diameter.

8. A downhole tool according to any of the preceding claims, wherein the filter wall has a surface area, and the plurality of filter openings cover at least 15% of the surface area, preferably 20% of the surface area, and more preferably at least 25% of the surface area.

9. A downhole tool according to any of the preceding claims, wherein the filter openings have a diameter of at least 1 mm, preferably at least 2 mm, and more preferably more than 3 mm.

10. A downhole tool according to any of the preceding claims, wherein the filter wall between the filter openings is impermeable.

11. A downhole tool according to any of the preceding claims, wherein the removable filter part (7) is detachably connected to the chamber wall (17).

12. A downhole tool according to any of the preceding claims, wherein the front end (9) is detachably connected to the chamber wall for removing the filter part.

13. A downhole tool according to any of the preceding claims, wherein the removable filter part (7) is detachably connected to the front end via a thread (16).

14. A downhole tool according to any of the preceding claims, wherein the chamber is formed by the chamber wall (17), the front end (9) and a face (28) facing the pump and the removable filter part (7) is detachably connected to the face.

15. A downhole tool according to any of the preceding claims, wherein the chamber is formed by the chamber wall (17), the front end (9) and a face (28) facing the pump and the removable filter part (7) is detachably connected to the chamber.P2888PC00

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