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Title:
DOWNHOLE TOOL AND METHOD FOR DISPLACING A SLEEVE IN A WELLBORE
Document Type and Number:
WIPO Patent Application WO/2019/182455
Kind Code:
A1
Abstract:
It is described a downhole tool (1) for displacing a slideable sleeve (50) under actuation of a stroker tool (100), the sleeve (50) being provided inside a casing string (501) in a wellbore (500), the casing string having openings (51), and wherein the sleeve (50) has a position relative to the casing (501) whereat it seals the openings (51), wherein the downhole tool (1) comprises: - a telescopic unit (2) comprising an inner telescopic element (21) and an outer telescopic element (22) that are moveable relative to each other over a predefined stroke (23), wherein a part of the stroke (23) has a significantly higher friction between the inner telescopic element (21) and the outer telescopic element (22) than a remainder of the stroke (23); - a tapered actuator (3) arranged at least partially within the inner telescopic element (21) and be-ing at least axially displaceable relative to the inner telescopic element (21), wherein the tapered actuator (3) is actuated by the stroker tool (100), in operational use; - a gripper device (4) mounted in a sidewall of the inner telescopic element (21) and being at least radially displaceable by axial displacement of the tapered actuator (3) relative to the inner telescopic element (21) for gripping the sleeve (50).

Inventors:
ZAMBRANO PUERTA, Mauro Antonio (15819 Copper Spring LN, HOUSTON, Texas, 77084, US)
Application Number:
NO2019/050057
Publication Date:
September 26, 2019
Filing Date:
March 15, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ALTUS INTERVENTION (TECHNOLOGIES) AS (Moseidveien 35, 4033 STAVANGER, 4033, NO)
International Classes:
E21B23/01; E21B34/14
Domestic Patent References:
WO2015115909A12015-08-06
WO2010114383A12010-10-07
WO2015076679A12015-05-28
Foreign References:
US4979561A1990-12-25
US5605366A1997-02-25
Attorney, Agent or Firm:
HÅMSØ PATENTBYRÅ AS (P.O. Box 171, 4301 Sandnes, 4301, NO)
Download PDF:
Claims:
C l a i m s

1 . A downhole tool (1 ) for displacing a slideable sleeve (50) under actuation of a stroker tool (100), the sleeve (50) being provided inside a casing string (501 ) in a wellbore (500), the casing string having openings (51 ), and wherein the sleeve (50) has a position relative to the casing (501 ) whereat it seals the openings (51 ),

c h a r a c t e r i z e d i n that the downhole tool (1 ) comprises:

- a telescopic unit (2) comprising an inner telescopic element (21 ) and an outer telescopic element (22) that are moveable relative to each other over a predefined stroke (23), wherein a part of the stroke (23) has a significantly higher friction between the inner tele scopic element (21 ) and the outer telescopic element (22) than a remainder of the stroke (23);

- a tapered actuator (3) arranged at least partially within the inner telescopic element (21 ) and being at least axially displaceable relative to the inner telescopic element (21 ), wherein the tapered actuator (3) is actuated by the stroker tool (100), in operational use;

- a gripper device (4) mounted in a sidewall of the inner telescopic element (21 ) and be ing at least radially displaceable by axial displacement of the tapered actuator (3) relative to the inner telescopic element (21 ) for gripping the sleeve (50).

2. The downhole tool (1 ) according to claim 1 , wherein the inner and outer telescopic ele ment (21 , 22) are provided with impediments (220) such that the impediments (220) touch each other at a specific position along the stroke to obtain the higher friction.

3. The downhole tool (1 ) according to claim 2, wherein the impediments (220) provides a reducing internal diameter of a portion the outer telescopic element (22).

4. The downhole tool (1 ) according to claim 2 or 3, wherein the impediments (220) provides an increasing outer diameter of a portion of the inner telescopic element (21 ).

5. The downhole tool (1 ) according to any of the preceding claims, wherein the inner tele scopic element (21 ) comprises a plurality of flexible elements (210), the impediments (220) being provided on the flexible elements (210) such that the flexible elements (210) displace at least radially inwards under a force at least equal to the force required to overcome the friction of the section within the stroke.

6. The downhole tool (1 ) according to any of the preceding claims, wherein the tapered ac tuator (3) comprises a groove (31 ) complementary to a guiding element (41 ) on the grip per device (4), the groove (31 ) forming an inclining angle relative to a longitudinal centre axis (10) of the actuator (3).

7. The downhole tool (1 ) according to any of the preceding claims, further comprising a bi asing element (5) acting on the tapered actuator (3), in operational use.

8. The downhole tool (1 ) according to any of the preceding claims, further comprising a locator tool (60) for locating the sleeve (50), wherein the locator tool (60) comprises at least one locator key (62) moveable in the radial direction by means of a spring (67), the at least one locator key (62) being complementary to a recess.

9. The downhole tool (1 ) according to any of the preceding claims, further comprising an end cap (6) connected to a free end portion (1 1 ) of the downhole tool (1 ).

10. A downhole assembly (7) comprising a stroker tool (100) and the downhole tool (1 ) ac cording to any of the preceding claims, c h a r a c t e r i z e d i n that the downhole tool (1 ) being mounted to the stroker tool (100).

1 1 . The downhole assembly (7) according to claim 1 0, wherein the stroker tool (100) com prises a stroker (101 ), the stroker (101 ) being moveable relative to the stroker tool (100).

12. The downhole assembly (7) according to claim 1 0 or 1 1 , wherein the stroker tool (100) is connected to the outer telescopic element (22).

13. The downhole assembly (7) according to any of the claims 10 to 12, wherein the stroker tool (100) comprises an anchor (102).

14. A method of displacing in an upstream direction a slideable sleeve (50) forming a part of a casing string (501 ) in a wellbore (500) using the downhole tool (1 ) according to any of the claims 1 -9, the casing string (501 ) having ports (51 ) that are sealable by the sleeve (50), c h a r a c t e r i z e d i n that the method comprises:

- providing the downhole tool (1 ) in the wellbore (500) at the sleeve (50) to be displaced ;

- gripping the sleeve by actuating a stroker tool (1 00);

- displacing the sleeve in the upstream direction by continuing the actuation to extend the downhole tool (1 ).

15. The method according to claim 14, comprising gripping the sleeve (50) by displacing the gripping device (4) at least radially outwards.

16. The method according to claim 15, comprising displacing the gripping device (4) at least radially outwards by displacing the tapered actuator (3) axially.

17. The method according to any of the claims 14 to 16, comprising extending the downhole tool (1 ) by displacing the inner telescopic element (21 ) relative to the outer telescopic el ement (22).

18. A method of displacing in an downstream direction a slideable sleeve (50) forming a part of a casing string (501 ) in a wellbore (500) using the downhole assembly (7) according to any of the claims 10-13, the casing string (501 ) having ports (51 ) that are sealable by the sleeve (50), c h a r a c t e r i z e d i n that the method comprises:

- providing the downhole assembly (7) in the wellbore (500) at the sleeve (50) to be dis placed;

- anchoring the stroker tool (100) to the sleeve (50);

- gripping the downhole tool (1 ) to the casing string (501 ) closer to a bottom of the well bore than the sleeve by actuating the stroker tool (100);

- displacing the sleeve in the downstream direction by continuing the actuation to extend the downhole tool (1 ).

19. The method according to claim 18, comprising extending the downhole tool (1 ) by dis placing the outer telescopic element (22) relative to inner telescopic element (21 ).

Description:
DOWNHOLE TOOL AND METHOD FOR DISPLACING A SLEEVE IN A WELLBORE

The invention relates to a downhole tool for displacing a sleeve forming a part of a casing string in a wellbore. The invention further relates to a method of displacing in a first direction the sleeve forming a part of the casing string in the wellbore using the downhole tool. The invention also re- lates to a method of displacing in a second direction the sleeve using a downhole assembly com prising the downhole tool and a stroker tool.

Hydrocarbon wells are drilled to ever longer distances and often deviate significantly. As the wells extend over long distances they may cross through various zones in the formation. Some zones may be desirable to produce from, others not. It may also be desirable to control the production from the various zones. Fluid treatment of a formation is often performed during well completion, production and well stimulation.

To enable fluid treatment of the formation, a displaceable sleeve may be employed as part of a casing string. Such a sleeve may be arranged in several locations along the casing, to gain access to the desired formation zones. The sleeve may comprise ports that are selectively opened or closed to obtain fluid communication between the wellbore and the relevant formation zone.

The sleeve may be controlled by means of a downhole tool deployed in the wellbore. The down hole tool may comprise means to engage with the sleeve and displace the sleeve axially, and thus open or close the ports. Fluid may be displaced in the wellbore and through the ports to treat the formation zone. Document WO2017/1 90217 discloses a downhole tool comprising a locator. The locator includes a wellbore coupler which is releasably retained relative to a locate profile in the wellbore. Once the wellbore coupler is aligned with the locate profile, the wellbore coupler engages with the locate profile by means of a locator block to impede relative displacement between the wellbore coupler and the locate profile. Prior to the wellbore coupler engaging with the locate profile, the wellbore coupler is retained by the inner surface of the wellbore.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art. The object is achieved through features, which are specified in the description below and in the claims that follow.

The invention is defined by the independent patent claim. The dependent claims define advanta geous embodiments of the invention. In a first aspect, the invention relates to a downhole tool for displacing a slideable sleeve under actuation of a stroker tool, the sleeve being provided inside a casing string in a wellbore, the casing string having openings, and wherein the sleeve has a position relative to the casing whereat it seals the openings, wherein the downhole tool comprises:

- a telescopic unit comprising an inner telescopic element and an outer telescopic element that are moveable relative to each other over a predefined stroke, wherein a part of the stroke has a signifi cantly higher friction between the inner telescopic element and the outer telescopic element than a remainder of the stroke;

- a tapered actuator arranged at least partially within the inner telescopic element and being at least axially displaceable relative to the inner telescopic element, wherein the tapered actuator is actuated by the stroker tool, in operational use;

- a gripper device mounted in a sidewall of the inner telescopic element and being at least radially displaceable by axial displacement of the tapered actuator relative to the inner telescopic element for gripping the sleeve.

The invention solves the abovementioned challenges by providing a downhole tool that may im- pede the displacement of the telescopic elements from a given position relative to each other, until a firm grip between a gripper device and the sleeve to be displaced is achieved. If a firm grip is not obtained prior to displacing the inner telescopic element relative to the outer telescopic element, the gripper device may move relative to the sleeve and thus not displace the sleeve. A force re quired to displace the telescopic elements relative to each other over the section creating the high- er friction between the telescopic elements may be higher than a force required to obtain a firm grip between the gripper device and the sleeve. As long as the force acting on the tapered actuator to displace the gripper device is lower than the force required to overcome the higher friction between the telescopic elements, the telescopic elements may not move relative to each other. The force acting to displace the actuator may increase until said force exceeds the force required to over- come the friction of the higher friction section. Once the friction of the higher friction section is over come, the telescopic elements may move relative to each other to displace the sleeve. At this point the sleeve is connected to the gripper device such that the sleeve moves axially together with the first telescopic element. In one embodiment, the term significantly higher should be understood as the part of the stroke having a friction that is at least a magnitude of two higher than the friction of the remainder of the stroke. In another embodiment, the term significantly higher should be under stood as the part of the stroke having a friction that is at least a magnitude of five higher than the friction of the remainder of the stroke. In a further embodiment, the term significantly higher should be understood as the part of the stroke having a friction that is at least a magnitude of ten higher than the friction of the remainder of the stroke.

From what is described above it may be understood that the invention provides a downhole tool that may seamlessly grip a sleeve in a wellbore and displace the sleeve. By seamlessly it should be understood that gripping the sleeve and displacing the sleeve may be performed in one contin uous operation, such as operating the stroker tool to deliver an increasing force.

By stroke it should be understood a length or distance over which the telescopic elements may be displaced axially relative to each other.

Another advantage of the invention is that the downhole tool may grip the sleeve to be displaced without depending on an external body or feature to impede displacement of the telescopic ele ments.

In one embodiment, the downhole tool may be used to displace a sleeve to form a fluid communi cation between the wellbore and a formation for performing for example well stimulation or fractur ing. In another embodiment, the downhole tool may be used to displace a sleeve to cut fluid com- munication between the wellbore and the formation after performing for example well stimulation or fracturing.

It should be understood that the downhole tool may be used to displace other elements than a sleeve, for example a valve port or another tool connected to the downhole tool. In one embodi ment, the downhole tool may be used to anchor to a fixed element, for example a casing or a pro- duction tubing.

In one embodiment, the telescopic elements may be provided with impediments such that the im pediments touch each other at a specific position along the stroke to obtain the higher friction. An impediment may be an element restricting the displacement of the telescopic elements relative to each other. The term restricting may be understood as impeding. An impediment may be a protru- sion. The impediments may be arranged on an inner surface of the outer telescopic element. The impediment may be arranged on the outer surface of the first telescopic element. The impediment may be arranged on both the inner surface of the outer telescopic element and the outer surface of the first telescopic element. By inner and outer surface, it is meant a surface that is facing towards and away, respectively, from a longitudinal centre axis of the downhole tool. In one embodiment, the impediment may be a high friction material.

In use, the telescopic elements may move at least axially with little friction relative each other when the impediments are not in contact. The friction may increase when the impediments touch each other. An increase in axial force may be required to displace the telescopic elements relative to each other past the impediments. In one embodiment, the impediments may provide a reducing internal diameter of a portion the outer telescopic element. The impediment may be a protrusion extending from the inner surface of the outer telescopic element. By the term reducing it may be understood that the impediment forms an inclining surface relative to the longitudinal axis of the outer telescopic element. Thus, the inner diameter may increase over the portion defined by the impediment.

In one embodiment, the impediments may provide an increasing outer diameter of a portion of the inner telescopic element. The impediment may be a protrusion extending from the outer surface of the inner telescopic element. By the term increasing it may be understood that the impediment forms an inclining surface relative to the longitudinal axis of the inner telescopic element. Thus, the outer diameter may increase over the portion defined by the impediment. In one embodiment, the protrusion may be arranged on an end portion of the inner telescopic element.

In one embodiment, the inner telescopic element may comprise a plurality of flexible elements, the impediments being provided on the flexible elements such that the flexible elements displace at least radially inwards under a force at least equal to the force required to overcome the friction of the section within the stroke. The flexible elements may be configured as a spring, wherein they return its initial position after being influenced by a force sufficient to displace them . In one embod iment, the flexible elements may be arranged to form a circular shape. The flexible elements may be arranged with a gap between each other to allow for the radial displacement without the flexible elements coming into contact with each other. In one embodiment, the tapered actuator may comprise a groove complementary to a guiding ele ment on the gripper device, the groove forming an inclining angle relative to a longitudinal centre axis of the actuator. The tapered actuator and the gripper device may be configured such that the gripper device slides along the tapered actuator when the tapered actuator is displaced. The grip per device may displace radially when the tapered actuator is displaced axially. The groove may partially envelop the guiding element such that the guiding element slides along the groove when the tapered actuator is displaced axially. The groove and the guiding element may be configured such that the gripper device is forced to displace radially when the tapered actuator is displaced axially. For example, this may ensure that the gripper device release from the sleeve when intend ed. In one embodiment, the downhole tool may further comprise a biasing element acting on the ta pered actuator, in operational use. The biasing element may provide a counteracting force on the tapered actuator, the counteracting force increasing with a displacement of the tapered actuator towards the free end of the downhole tool. In one embodiment, the force from the biasing element may increase with an outwards radial displacement of the gripper device. In one embodiment, the biasing element may be a spring. In one embodiment, the biasing element may be any element providing a resilient resistive force, for example a hydraulic cylinder. The biasing element may be in a compressed state when the downhole tool grips the sleeve. The biasing element may provide a means for releasing the gripper device from the sleeve. The biasing element may move the tapered actuator axially to displace the gripper device radially inwards. The biasing element may constitute a fail-safe mechanism, ensuring the downhole tool is released from the sleeve if the stroker tool loses power. In one embodiment, the downhole tool may comprise a locator tool for locating the sleeve, wherein the locator tool comprises at least one locator key moveable in the radial direction by means of springs, the at least one locator key being complementary to a recess. In one embodiment, the locator tool may comprise more than one locator key. In one embodiment, the locator tool may comprise four locator keys. During running in the wellbore, the locator keys are initially disposed in a retracted position as a result of abutting against an inner surface of the wellbore. In the retracted position, the springs are compressed and acting to push the locator keys in an outwardly radial direction.

A stiffness of the springs may be limited to reduce a friction between the locator keys and the inner surface of the wellbore during displacement of the downhole tool in the wellbore. The recess may form an increase in the inner diameter of the wellbore. The recess may be located on the sleeve, or another location in the wellbore, such as on the casing below the sleeve. The sleeve allows the locator keys to displace radially outwards when aligned with the recess. An outwardly radial dis placement of the locator keys may indicate that the downhole tool is in position for shifting the sleeve. Said indication of the downhole tool being in position may be transmitted to an operator of the downhole tool. In one embodiment, the indication may be an increase in a cable pull force in a ca ble connected to the downhole tool. In one embodiment, the locator tool may comprise means, such as a sensor, for signalling that the locator keys displace radially outwards.

The locator keys and the recess may form a tapered surface such that a certain axial load on the downhole tool may cause the locator keys to slide relative to the recess and displace radially in wards, and thus disengage from the recess.

In one embodiment, the downhole tool may comprise an end cap connected to a free end portion of the downhole tool. The end cap may seal the lower end portion of the tool. In one embodiment the end cap may guide the downhole tool in the wellbore. In one embodiment, the end cap may have a rounded shape. In one embodiment, the end cap may centralize the downhole tool in the wellbore.

In one embodiment, a downhole assembly may comprise a stroker tool and the downhole tool ac cording to any of the preceding claims, the downhole tool being mounted to the stroker tool. The stroker tool may create the force required to grip the sleeve and move the sleeve by displacing the telescopic elements relative to each other. The stroker tool is not described in further detail as it is well known from the prior art. In one embodiment, the stroker tool may comprise a stroker, the stroker being moveable relative to the stroker tool. The stroker may be a rod. The stroker may be configured to interact with the ta pered actuator. The stroker may be connected directly or indirectly to the tapered actuator to dis place the tapered actuator axially. In one embodiment, the stroker tool may be connected to the outer telescopic element. Connecting the stroker tool to the outer telescopic element enables the inner telescopic element to be dis placed relative to the stroker tool. The outer telescopic element and the stroker tool may be dis placed relative to the first telescopic element and the stroker.

In one embodiment, the stroker tool may comprise an anchor. In one embodiment, the anchor may connect the stroker tool to a casing, a production tubing or another tubular. The anchor may cen tralize the stroker tool in the wellbore. The anchor may prevent the stroker tool from displacing at least axially.

In a second aspect, the invention relates to a method of displacing in an upstream direction a slideable sleeve forming a part of a casing string in a wellbore using the downhole tool, the casing string having ports that are sealable by the sleeve, wherein the method comprises:

- providing the downhole tool in the wellbore at the sleeve to be displaced;

- gripping the sleeve by actuating an axial force;

- displacing the sleeve in the first direction by increasing the axial force.

The method may enable a seamless operation of displacing the sleeve. The axial force may be provided by means of for example a stroker tool as known from the prior art. The first direction may be understood as a direction to open the sleeve.

In one embodiment, the method may comprise gripping the sleeve by displacing a gripping device at least radially outwards. The gripper device may grip the sleeve such that they are fixed from moving relative to each other. In one embodiment, the method may comprise displacing the gripping device at least radially out wards by axially displacing a tapered actuator. The actuator may be displaced by means of the axial force.

In one embodiment, the method may comprise extending the downhole tool by displacing an inner telescopic element relative to an outer telescopic element. The telescopic elements may displace relative to each other by means of the increased axial force.

In a third aspect, the invention relates to a method of displacing in an downstream direction a slideable sleeve forming a part of a casing string in a wellbore using the downhole assembly, the casing string having ports that are sealable by the sleeve, wherein the method comprises:

- providing the downhole assembly in the wellbore at the sleeve to be displaced; - anchoring the stroker tool to the sleeve;

- gripping the downhole tool to the casing string closer to a bottom of the wellbore than the sleeve by actuating the stroker tool;

- displacing the sleeve in the second direction by continuing the actuation to extend the downhole tool.

The second direction may be understood as a direction to close the sleeve.

In one embodiment, the method may comprise extending the downhole tool by displacing the outer telescopic element relative to inner telescopic element.

In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1 a shows a cross-section of a downhole tool according to one embodiment of the inven tion;

Fig. 1 b shows a cross-section of a downhole assembly according to one embodiment of the invention; Fig. 2 shows, in a perspective view, the downhole assembly in a smaller scale than figure

1 b;

Fig. 3 shows a cross-section of the downhole assembly positioned in a wellbore; Fig. 4 shows several detailed views of an inner telescopic element in a larger scale than figure 1 a; Fig. 5 shows a cross-section of an outer telescopic element in the same scale as figure 4; Fig. 6 shows a cross-section and an end view of a tapered actuator in the same scale as figure 4;

Fig. 7 shows a perspective view of a gripper device in a larger scale than figure 4; Fig. 8 shows, schematically, a method, in three steps (I, II, II), of displacing the sleeve in a first direction;

Fig. 9 shows, schematically, a method, in two steps (IV, V), of displacing the sleeve in a second direction; and

Fig. 10 shows a cross-section of the downhole tool comprising a locator tool. The figures are depicted in a simplified manner, and details that are not relevant to illustrate what is new with the invention may have been excluded from the figures. The different elements in the figures may necessarily not be shown in the correct scale in relation to each other. Equal reference numbers refer to equal or similar elements. In what follows, the reference numeral 1 indicates a downhole tool according to one embodiment of the invention. Figure 1 a shows the downhole tool 1 comprising a telescopic unit 2. The telescopic unit 2 comprises a first telescopic element 21 and a second telescopic element 22. The first tele scopic element 21 is shown to be partially disposed within the second telescopic element 22. The telescopic elements 21 , 22 are shown to be arranged concentrically relative to each other. The downhole tool 1 further comprise a tapered actuator 3. The tapered actuator 3 is shown to the dis posed within the first telescopic element 21 . It should be understood that the tapered actuator 3 may be disposed partly within the first telescopic element 21 . It should also be understood that the tapered actuator 3 may be displaced, in use, from a position within the first telescopic element 21 , to a position outside the first telescopic element 21 . The tapered actuator 3 is shown to be ar- ranged concentrically relative to the first telescopic element 21 .

The downhole tool 1 also comprise a coupling device 4. The coupling device 4 is shown to have a gripping element 40. In the figures the coupling device 4 is shown to have only one gripping ele ment 40. However, it should be understood that the coupling device 4 may comprise a plurality of gripping elements 40. In a preferred embodiment, the coupling device 4 comprise three gripping elements 40. The gripping element 40 extends through a sidewall 21 1 of the first telescopic ele ment 21 . The gripping element 40 is shown in a retracted position. In the retracted position, a max imum outer diameter formed by the coupling device 4 is less than a maximum outer diameter of the downhole tool 1 . This may ensure that the gripping element 40 does not contact a surface of the wellbore 500 or any other objects during lowering into the wellbore 500. The gripping element 40 is also shown to be arranged against the tapered actuator 3 (see also figure 6a and 6b). In use, an axial displacement of the tapered actuator 3 causes the gripping ele ment 40 to slide along the actuator 3. The sliding results in the gripping element 40 displacing radi ally, either outwards or inwards, depending on the direction of the axial displacement of the actua tor 3. The gripping element 40 is restricted from substantially moving in any other direction than radially. The gripping element 40 is shown to be restricted by an opening in the sidewall 21 1 of the first telescopic element 21 , through which the gripping element 40 extends. An interface between the tapered actuator 3 and the gripping element 40 will be discussed in more detail later.

The downhole tool 1 may comprise a biasing element 5. The biasing element 5 is depicted as a spring. It should be understood that the biasing element 5 may be another element providing a resilient resistive force, for example a hydraulic cylinder. The biasing element 5 is compressed with an axial displacement of the tapered actuator 3 towards a free end portion 1 1 of the downhole tool 1 . As the biasing element 5 is compressed it creates a counterforce acting on the tapered actuator 3. The counterforce increases with a further displacement of the tapered actuator 3 towards the free end portion 1 1 . The counterforce from the biasing element 5 is sufficient to displace the ta pered actuator 3 in an axial direction away from the free end portion 1 1 . Thus, the biasing element 5 may provide a fail-safe mechanism. A fail-safe mechanism should be understood as a mecha- nism that brings the downhole tool 1 to safe state if another element fails. One example may be if the stroker tool 100 fails and thus not manage to disconnect the coupling device 4 from the body 50. The biasing element 5 may then displace the tapered actuator 3 to disconnect the coupling device 4 from the body 50 such that the downhole tool 1 is free to move in the wellbore 500.

Figure 1 b shows the downhole assembly 7 comprising the downhole tool 1 and the stroker tool 100. The downhole tool 1 is shown with a crossover 8 connecting a stroker 101 on the stroker tool

100 to the tapered actuator 3. The crossover 8 may be an interchangeable element to fit different types of strokers 101 . The crossover 8 is provided with an interface portion 82 configured to re ceive the stroker 101 . The interface portion 82 may be different for different crossovers 8 to suits different strokers 101 . The crossover 82 is connectable to the stroker 101 and the tapered actuator 3 such that they move at least axially together. In one embodiment, the crossover 8, the stroker

101 and the tapered actuator 3 may be rotatable relative to each other.

Figure 2 shows that the first telescopic element 21 is provided with openings 213 in a sidewall 21 1 (see figure 1 a). The first telescopic element 21 in the figures is provided with three openings 213 (only two shown). However, it should be understood that the first telescopic element 21 may com- prise less or more openings 213 in another embodiment. The gripping element 40 is provided in one of the openings 213. However, it should be understood that a gripping element 40 may be provided in each of the openings 213 in a preferred embodiment. The gripping element 40 extends through the opening 213. The gripping element 40 is shown in a retracted configuration. In one embodiment, the gripping element 40 may be retracted fully within the first telescopic element 21 . The opening 213 is configured such that the gripping element 40 is restricted from moving in any direction other than substantially radially. The gripping element 40 may abut against a mouth por tion 214 of the opening 213 if the gripping element 40 is rotated and/or displaced axially.

The second telescopic element 22 is shown to have a circumferential element 221 . The circumfer ential element 221 has an outer diameter which is larger than a sidewall 222 of the second tele- scopic element 22. The circumferential element 221 may provide a means for centralizing the downhole tool 1 in the wellbore 500. In another embodiment, the circumferential element 221 may provide a means for positioning the downhole tool 1 a minimum distance from an inner sidewall 502 of the wellbore 500. The inner sidewall 502 may be the inner sidewall 502 of the casing 501 or the sleeve 50. In one embodiment, the circumferential element 221 may prevent the gripping ele- ment 40, in the retracted position, from contacting the sidewall 502 as the downhole tool 1 is run in or out of the wellbore 500. The sleeve 50 may form part of a casing string 501 in a wellbore 500, see figure 3. The casing string 501 may comprise one or several sleeves 50. Only one sleeve 50 is shown in the figures.

The sleeve 50 form a barrier towards ports 51 in the casing 501 . The ports 51 create a channel for fluid communication between the wellbore 500 and a formation 600. By displacing the sleeve 50, the ports 51 may be opened or closed. The ports 51 are shown in a closed position in figure 3.

The casing 501 is provided with a recess 503 over a length. The sleeve 50 is arranged in the re cess 503 such that an inner diameter of the sleeve 50 is equal to an inner diameter of a section of the casing 501 not having the recess 503. Thus, the wellbore 500 form a uniform inner diameter. Uniform may also be understood as flush. The length of the recess 503 is such that it allows suffi- cient displacement of the recess to open the ports 51 , but it restricts excessive displacement.

Figure 4 shows a cross-section A-A, a sideview and a perspective view B of the inner telescopic element 21 . The inner telescopic element 21 is shown with six flexible elements 210. It should be understood that the inner telescopic element 21 may comprise less than or more than six flexible elements 210 in another embodiment. The flexible elements 210 form a circular shape. The flexible elements 210 are arranged with even spacing and a gap 21 1 between each flexible element 210.

In use, the flexible elements 210 may be displaced radially inwards without touching each other.

The inner telescopic element 21 comprise a first end portion 201 and a second end portion 202. The first end portion 201 is shown to have a larger outer diameter, in the following called OD, than an OD of the second end portion 202. A shoulder 203 forms the transition from the larger OD to the smaller OD. In this specific embodiment, the shoulder 203 also forms a displacement restriction. The shoulder 203 restricts the displacement of the inner telescopic elements 21 , 22 relative to each other. The shoulder 203 restricts how far into the outer telescopic element 22 the inner telescopic element 21 may be displaced. In the figures, this is achieved by the OD of the first end portion 201 being larger than an inner diameter, in the following called ID, of a first end portion 221 (see figure 5) of the outer telescopic element 22.

The inner telescopic element 21 may be provided with an impediment 204. The impediment 204 is shown as protrusions extending from an outer surface 205 of the flexible elements 210, the protru- tions 204 being arranged on a free end 2020 of each flexible element 210. It should be understood that the impediment 204 may be any element that increase the friction between the telescopic ele- ments 21 , 22 at the section of the stroke 23, for example a high friction material such as a rubber, a fluid in combination with a pressure relief valve, a gear or magnets. The stroke 23 is defined by arrows in figure 8.

The outer telescopic element 22 may be provided with an impediment 220, see figure 5. The im pediment 204 is shown as an annular protrusion extending from an inner surface 224 of the outer telescopic element 22. Similar to the impediment 204 on the inner telescopic element 21 , it should be understood that the impediment 220 may be any element that increase the friction between the telescopic elements 21 , 22 at the section of the stroke 23, see examples above.

The impediment 204 on the inner telescopic element 21 may form an increasing OD of a portion of the inner telescopic element 21 . By increasing OD of a portion, it should be understood that the OD may increase over a length of the inner telescopic element 21 . Thus, a surface 2040 of the imped iment 204 may form an inclining angle relative to a longitudinal axis 10 of the inner telescopic ele ment 21 . The impediment 220 on the outer telescopic element 22 may form a reducing ID of a por tion of the outer telescopic element 22. By reducing ID of a portion, it should be understood that the ID may reduce over a length of the outer telescopic element 22. Thus, a surface 225 of the imped- iment 204 may form an inclining angle relative to a longitudinal axis 10 of the outer telescopic ele ment 22.

In use, the impediments 204, 220 may contact each other as either or both of the telescopic ele ments 21 , 22 are displaced relative to each other. Thus, the impediments 204, 220 may imped said displacement. The impediments 204, 220 may be configured such that the inclining surfaces 2040, 225 are substantially parallel to each other. With an increasing axial force acting on either or both of the telescopic element 21 , 22, the flexible elements 210 may bend, such that the free end 2020 displace radially inwards at a certain force as the inclining surfaces 2040, 225 slide substantially parallel to each other. At a position where an OD formed by the impediments 204 on the flexible element 210 are substantially equal to or less than the ID formed by the impediments 220 on the outer telescopic element 22, the impediments 204, 220 may slide past each other and the displace of the telescopic elements 21 , 22 may proceed with a reduced axial force. It should be understood that the description above is relevant for axial displacement in two opposite directions. The two directions may be described as mating and separation of the telescopic elements 21 , 22

A position of the telescopic element 21 , 22 where the shoulder 203 is in contact with, or at least close to, a sidewall 223 of the outer telescopic element 22 may correspond to a first end position of a stroke 23 of the telescopic elements 21 , 22 relative to each other. The first end position is illus trated in figure 1 a, 3 and 8 step I and II. A position of the telescopic elements 21 , 22 where the impediments 204 on the inner telescopic element 21 is closer to the first end portion 221 of the outer telescopic element 22 than the impediment 220 on the outer telescopic element 22 may cor- respond to a second end position of the stroke of the telescopic elements 21 , 22 relative to each other. The second end position is illustrated schematically in figure 8 step III.

Figure 6a shows a cross section of the tapered actuator 3 forming a cone shape. The actuator 3 comprise a receiving portion 33. The receiving portion 33 is configured to receive and connect to the crossover 8. The actuator 3 further comprise a groove 31 for receiving the gripper device 40. The actuator 3 is shown to have three grooves 31 , see figure 6b. It should be understood that the number of grooves 31 may be different in another embodiment. In a preferred embodiment, the number of grooves 31 and the number gripper devices 40 are equal. The grooves 31 are comple- mentary to a guiding element 42 on the gripper device 40. The groove 31 may partially envelop the guiding element 42. In use, the groove 31 may ensure the gripper device 40 is pulled radially in wards when disconnecting from the sleeve 50.

Figure 7 shows the gripper device 40 comprising teeth 43 for providing a firm grip against the sleeve 50. In one embodiment, the teeth 43 may be produced from a harder material than the sleeve 50 is produced from. Thus, the teeth 43 may not deform in use. The gripper device 40 is further provided with a base portion 44. The base portion 44 is complementary to a recess 34 in the tapered actuator 3. The base portion 44 provides a stable support against the actuator 3, reducing the possibility for the gripper device 40 to rotate. Figure 8 shows schematically a method of displacing the sleeve 50 in a first direction using the downhole tool 1 . In this particular embodiment, the first direction corresponds to opening for fluid communication. The method is shown to comprise of three steps, I, II and III. Step I shows the downhole tool 1 provided in a wellbore 500 at the sleeve 50 in a pre-set state. Ports 51 for fluid communication between the wellbore 500 and the formation 600 are closed in this step. Step II shows the tapered actuator 3 axially displaced by the stroker 101 on the stroker tool 100. The grip per device 4 is displaced radially by the actuator 4 and is gripping the sleeve 50. At this point the tapered actuator 3 is displaced relative to the inner telescopic element 21 . The telescopic elements 21 , 22 are restricted from displacing by the impediments (not shown). Step III shows the sleeve 50 axially displaced and the ports 51 forming fluid communication between the wellbore 500 and the formation 600. In step III, the force from the stroker 101 exceed the friction force between the tele scopic elements 21 , 22 caused by the impediments. Thus, the inner telescopic element 21 displace relative to the outer telescopic element 22. The actuator 3 and the gripper device 4 move with the inner telescopic element 21 . So does the sleeve 50 as it is connected to the gripper device 4.

Step II and III also shows that the biasing element 5 is in a compressed state. In the compressed state, the biasing element 5 exert a force on the actuator 3. This force may displace the actuator 3 to disconnect the gripper device 4 from the sleeve 50 should the stroker tool 100 lose power.

Figure 9 shows schematically a method of displacing the sleeve 50 in a second direction using the downhole apparatus 7. In this particular embodiment, the second direction corresponds to closing for fluid communication between the wellbore 500 and the formation 600. The method is shown to comprise of two steps, IV and V. Step IV shows the downhole assembly 7, wherein the stroker tool 100 is provided at the sleeve 50 and the downhole tool 1 is provided at the casing string 501 past the sleeve 50. First, the stroker tool 100 is anchored to the sleeve 50 by means of an anchor 102. The anchor 102 fixes the position of the stroker tool 100 relative to the sleeve 50. Second, the downhole tool 1 grips the casing 501 similarly to the procedure described under step II above. The stroker 101 is operated similarly as described under step III above. However, in this embodiment, the inner telescopic element 21 is restrained from displacing as the gripper device 4 grips the cas- ing 501 , which is fixed. Thus, the outer telescopic element 22 displace together with the stroker tool 100, and thus the sleeve 50.

The downhole tool 1 may be provided with a locator tool 60, as shown in figure 10. The locator tool 60 is shown to be arranged on the free end portion 1 1 . The locator tool 60 replaces the end cap 6 depicted in for example figure 1 a. However, the locator tool 60 may be provided with an alternative end cap 61 , serving the same purpose as the end cap 6 in figure 1 a.

The locator tool 60 comprises at least one locator key 62. In this particular embodiment, the down hole tool 1 is provided with four locator keys 62 (only two shown). The locator keys 62 are dis placeable in the radial direction relative to the downhole tool 1 within a slot 63. A depth of the slot 63 defines a radial displacement stroke of the locator keys 62. Outwards radial displacement of the locator keys 62 are restricted by projections 64a, 64b on a locator body 66. At a maximum out wards radial displacement, a first end portion 65a and a second end portion 65b of the locator keys 62 abut against the projections 64a, 64b.

The locator keys 62 are biased by springs 67 arranged on an inside of the locator keys 62. The inside should be understood as being closer to the longitudinal axis 10. The springs 67 act to push the locator keys 62 radially outwards. In a preferred embodiment, a stiffness of the springs 67 is sufficient to create a force displacing the locator keys 62 radially outwards, but sufficiently low to avoid excessive friction between the locator keys 62 and an internal surface 502 of the wellbore 500. The locator keys 62 forms a first tapered surface 68a and a second tapered surface 68b. The re cess (not shown) may form a surface being complementary to the locator keys 62. The recess forms an increase in the internal diameter of the wellbore. With the locator keys 62 disposed in the recess, a certain axial load exerted on the downhole tool 1 will displace the locator keys 62 radially inwards as they may slide relative to the recess. During a downwards movement of the downhole tool 1 , the locator keys 62 will engage with the recess when aligned. However, an angle of the first tapered surface 68a relative to the longitudinal axis 10 is such that the locator keys 62 do not substantially restrict a further downwards movement of the downhole tool 1 . The first tapered surface 68a may slide against the surface of the recess and the locator keys 62 displace radially inwards, such that the locator tool 60 may pass the recess with relative ease.

A depth measuring device (not shown) on the downhole tool 1 may tell an operator that the locator tool 60 is positioned past the sleeve 50. Thereafter, the downhole tool 1 may be displaced upwards in the wellbore 500. The locator keys 62 will again displace radially outwards when aligned with the recess. An angle of the second tapered surface 68b relative to the longitudinal axis 10 is higher relative to the first tapered surface 68a. This results in a higher axial force required to shift the loca- tor keys 62 radially inwards and thus disengage the locator keys 62 from the recess, when moving upwards in the wellbore 500. This will cause an increase in a cable pull load that may indicate to the operator that the locator tool 60 is in position.

The operation described in the last to sections may be repeated several times to verify that the locator tool 60 is at the recess, and to ensure that the increase in cable pull load is not a false read ing.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without depart ing from the scope of the appended claims.