阅读说明：本技术 取回系统 (Retrieval system ) 是由 R·索默尔 于 2018-07-24 设计创作，主要内容包括：本发明涉及一种取回系统,其用于从具有限位部和顶部的金属井管结构取回井部件如塞子,所述取回系统包括工具管柱,该工具管柱具有纵向延伸方向并包括构造成与井部件连接的连接工具、具有第一部分和能与连接工具连接并能相对于第一部分运动以提供沿纵向延伸方向的轴向力的第二部分的力发生器、具有用于锚固工具管柱的至少一个可突伸元件的锚固区段,其中,取回系统还包括安全单元,其围绕工具管柱并具有至少一个壁部和构造成抵靠限位部的至少一个抵靠表面,所述至少一个可突伸元件抵靠。此外,本发明还涉及一种井下系统和一种井下井部件的取回方法。(The present invention relates to a retrieval system for retrieving a well component, such as a plug, from a well tubular metal structure having a stopper portion and a top portion, the retrieval system comprising a tool string having a longitudinal extension and comprising a connection tool configured to be connected with the well component, a force generator having a first part and a second part connectable with the connection tool and movable relative to the first part for providing an axial force in the longitudinal extension, an anchoring section having at least one projectable element for anchoring the tool string, wherein the retrieval system further comprises a safety unit surrounding the tool string and having at least one wall portion and at least one abutment surface configured to abut against the stopper portion, the at least one projectable element abutting. Furthermore, the invention relates to a downhole system and a method of retrieving a downhole well component.)

1. A retrieval system (100) for retrieving a well component (30), such as a plug, from a well tubular metal structure (31) having a stopper portion (32) and a top portion (33), the retrieval system comprising:

-a tool string (1) having a longitudinal extension direction (10) and comprising:

-a connection tool (2) configured to be connected with the well component;

-a force generator (3) having a first portion (4) and a second portion (5), the second portion being connectable with the connection means and movable relative to the first portion to provide an axial force in the longitudinal extension direction; and

-an anchoring section (6) having at least one projectable element (7) for anchoring the tool string,

wherein the retrieval system further comprises a safety unit (8) surrounding the tool string and having at least one wall portion (9) and at least one abutment surface (11) configured to abut the stop portion, the at least one projectable element abutting the wall portion of the safety unit to anchor the tool string in the safety unit.

2. The retrieval system of claim 1, wherein the tool string is connected to the top portion via a wireline (12).

3. The retrieval system of claim 1 or 2, wherein the safety unit has an Outer Diameter (OD) greater than the tool string_T) Inner Diameter (ID) of_S)。

4. The retrieval system of claim 3, wherein the inner diameter of the safety unit is less than 30% larger than the outer diameter of the tool, preferably less than 20% larger than the outer diameter of the tool, more preferably less than 10% larger than the outer diameter of the tool.

5. The retrieval system of any of the preceding claims, wherein the safety unit has a first unit part (14) and a second unit part (15), the first unit part having the abutment surface, the first unit part having an inner diameter larger than an inner diameter of the second unit part, the at least one projectable element abutting a wall of the second unit part of the safety unit.

6. The retrieval system of any of claims 1-5, wherein the safety unit has a first unit part (14) and a second unit part (15), the first unit part having the abutment surface, the first unit part having an outer diameter larger than an outer diameter of the second unit part, the at least one projectable element abutting a wall of the second unit part of the safety unit.

7. The retrieval system of any of the preceding claims, where the security unit is made of metal.

8. The retrieval system of any of the preceding claims, wherein the connection means may protrude beyond the abutment surface in the longitudinal extension direction.

9. The retrieval system of any one of the preceding claims, wherein the safety unit has a plurality of arms (17), each arm having an end face facing away from the top and constituting the abutment surface.

10. The retrieval system of any of the preceding claims, wherein the anchoring section has at least two projectable elements (7) arranged in a same cross-sectional plane perpendicular to the longitudinal extension direction.

11. The retrieval system of any one of the preceding claims, wherein the tool string has a first end face (18) facing the top, a force being applicable on the first end face to slightly move the tool string relative to the safety unit to release the connection tool from the well component, so that the tool string can be pulled out of the well without retrieving the well component.

12. The retrieval system of any of the preceding claims, wherein the tool string further includes a cleaning tool (19) configured to expel or draw fluid to clean a profile (20) in the well component.

13. A downhole system comprising:

-a well tubular metal structure (31) in a borehole of a well, the well tubular metal structure comprising a stopper (30) and a stopper (32); and

-the retrieval system (100) of any one of the preceding claims.

14. A method of retrieving a downhole well component, comprising:

-arranging a tool string (1) of the retrieval system (100) according to any of claims 1-12 within a safety unit (8);

-anchoring the tool string inside the safety unit by projecting a projectable element (7);

-introducing the retrieval system into the well tubular metal structure (31) until the abutment surface (11) rests on the stopper part (32);

-moving the second part (5) of the force generator (3) relative to the first part (4) until the connection tool (2) engages the well component (30); and

-pulling the well member by retracting the second part of the force generator in order to retrieve the well member.

15. A method of retrieving a downhole well component according to claim 14, comprising detecting a malfunction during retrieving the well component (30) and releasing the connection tool (2) by providing a tapping force at an end face (18) of the tool string (1).

Technical Field

The present invention relates to a retrieval system for retrieving a well component, such as a plug, from a well tubular metal structure. Furthermore, the invention relates to a downhole system and a method of retrieving a downhole well component.

Background

When a plug, such as a crown plug, is pulled at the top of the well, the intervention tool is dipped into the well and rests in a stop located at a known distance from the plug to be retrieved. The intervention tool then moves the GS pulling tool or similar connecting tool locked into the plug axially and then pulls the plug by pulling back the connecting tool in an upward direction. However, in the event that the plug becomes stuck, the interventional tool can also become stuck between the plug and the stop and the conventional last method of disconnecting the tool by tapping on the tip of the tool is not effective due to the fact that the tool cannot move down due to the stop.

Disclosure of Invention

It is an object of the present invention to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More particularly, it is an object to provide an improved retrieval system which can be released even in case an interventional tool gets stuck inside the plug.

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 retrieval system for retrieving a well component, such as a plug, from a well tubular metal structure having a resistive portion and a top portion, comprising:

-a tool string having a longitudinal extension direction and comprising:

-a connection tool configured to be connected with the well component;

-a force generator having a first portion and a second portion, the second portion being connectable with the connection means and movable relative to the first portion to provide an axial force in the direction of longitudinal extension; and

an anchoring section having at least one projectable element for anchoring the tool string,

wherein the retrieval system further comprises a safety unit surrounding the tool string and having at least one wall portion and at least one abutment surface configured to abut the stop portion, the at least one projectable element abutting the wall portion of the safety unit to anchor the tool string in the safety unit.

The tool string may be connected to the top via a wireline.

Furthermore, the safety unit may surround the tool string.

Furthermore, the safety unit may be stackable with the tool string, when seen in a cross-section along the longitudinal direction of the tool string.

Furthermore, the safety unit may project in front of the connection tool and extend beyond the tool string.

Furthermore, the outer diameter of the part of the safety unit protruding beyond the tool string may be larger than the outer diameter of the tool string.

Furthermore, the safety unit may overlap the projectable element and project in front of the connection tool and extend beyond the tool string.

Furthermore, the abutment surface may extend beyond the tool string.

Further, the safety unit may have an inner diameter that is larger than an outer diameter of the tool string.

Furthermore, the safety unit may be a tubular sleeve.

Furthermore, the inner diameter of the safety unit may be less than 30% larger than the outer diameter of the tool, preferably less than 20% larger than the outer diameter of the tool, more preferably less than 10% larger than the outer diameter of the tool.

Furthermore, the safety unit may have a first unit part and a second unit part, the first unit part may have an abutment surface and the first unit part may have an inner diameter larger than the inner diameter of the second part, the at least one projectable element abutting a wall of the second unit part of the safety unit.

In this way, the projectable member does not need to project radially to such an extent that the projectable element must abut the wall of the first unit part.

The safety unit may have a first unit part and a second unit part, the first unit part may have an abutment surface and the first unit part may have an outer diameter larger than an outer diameter of the second part, the at least one projectable element abutting a wall of the second unit part of the safety unit.

Furthermore, the safety unit may be made of metal.

Furthermore, the connecting means may project beyond the abutment surface in the longitudinal extension direction.

Furthermore, the safety unit may have a plurality of arms, each arm having an end face facing away from the top and constituting the abutment surface.

Furthermore, the anchoring section may have at least two projectable elements arranged in the same cross-sectional plane perpendicular to the longitudinal extension direction.

Furthermore, the tool string may have a first end face facing the top, on which a force may be applied to slightly move the tool string relative to the safety unit to release the connection tool from the well component, so that the tool string can be pulled out of the well without retrieving the well component.

Additionally, the tool string may further include a cleaning tool configured to expel or draw fluid to clean the profile in the well component.

The cleaning tool may be disposed between the connecting tool and the force generator.

The force generator may be hydraulically driven by a pump driven by a motor powered by an electrical cable.

The invention also relates to a downhole system comprising:

-a well tubular metal structure in a borehole of a well, the well tubular metal structure comprising a stopper and a plug; and

-a retrieval system according to any of the preceding claims.

The invention also relates to a method of retrieving a downhole well component, comprising:

-arranging a tool string of the retrieval system according to the invention within a safety unit;

-anchoring the tool string inside the safety unit by projecting the projectable element;

-introducing the retrieval system into the well tubular metal structure until the abutment surface rests on the stop portion;

-moving the second portion of the force generator relative to the first portion until the connection tool engages the well component; and

-pulling the well component by retracting the second part of the force generator in order to retrieve the well component.

The method of retrieving a downhole well component according to the invention may comprise detecting a failure occurring during retrieval of a well component and releasing the connection tool by providing a tapping force at an end face of the tool string.

Drawings

The invention and many of its advantages will be described in more detail below with reference to the accompanying schematic drawings, which show, for purposes of illustration, only some non-limiting embodiments, in which:

FIG. 1 shows a partial cross-sectional view of a retrieval system having a tool string disposed within a sleeve-shaped safety unit for retrieving a plug;

2A-C illustrate a number of different embodiments of a security unit;

FIG. 3 shows a partial cross-sectional view of another retrieval system having a tool string disposed inside a sleeve-shaped safety unit; and

FIG. 3A illustrates a partial cross-sectional view of a portion of the retrieval system of FIG. 3;

all the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary for the elucidation of the invention, other parts being omitted or merely suggested.

Detailed Description

Figure 1 shows a retrieval system 100 for retrieving a well component 30, such as a plug, from a well tubular metal structure 31 having a stopper 32 and a top 33 (shown in figure 3). The stopper portion 31 is disposed at a predetermined distance from the well member 30. The retrieval system comprises a tool string 1 having a longitudinal extension 10 and comprising a connection tool 2 configured to be connected with a well component. The tool string 1 comprises a force generator 3 for providing an axial force in the longitudinal extension direction of the well tubular metal structure. The force generator 3 has a first part 4 and a second part 5, and the second part 5 is fastened to the connection tool 2 and is movable relative to the first part when providing an axial force in the longitudinal extension direction, for example to pull and retrieve a plug from the well tubular metal structure. The tool string 1 further comprises an anchoring section 6 having a plurality of projectable elements 7 for anchoring the tool string when the force generator pulls the plug by retracting the second portion 5 towards the stationary first portion 4. Thus, when to connect the plug, the second part of the force generator 3 moves away from the first part and when connected to the component, i.e. the plug, the second part moves in the opposite direction towards the first part and pulls the plug. The retrieval system further comprises a safety unit 8 surrounding the tool string and having a wall portion 9 and an abutment surface 11 abutting the stop portion 32. The projectable element abuts against a wall of the safety unit to anchor the tool string 1 inside the safety unit 8. The safety unit 8 is a tubular pipe, such as a tubular sleeve, in which the tool string is arranged and anchored, so that the tool string is not directly anchored inside the well tubular metal structure 31. The abutment surface 11 of the safety unit 8 abuts a stop, such as a stop, and the connecting tool engages the profile 20 in the plug 30 when the second part 5 of the force generator 3 is moved away from the first part, and the plug is pulled out of engagement with the well tubular structure 31 when the second part is retracted again. The connection tool may be any type of connection tool, such as a GS tool, a setting tool, a fishing tool, or an overshot capable of engaging a component in a well.

By having the safety unit 8, the connection tool 2 can be released from the plug even in case the plug gets stuck in the well tubular metal structure and thus the tool string gets stuck as well. It is possible to release the connecting tool by simply tapping on the end face 18 of the tool string, and by means of this tapping action the tool string is tapped slightly downwards relative to the safety unit, which remains stationary during the tapping operation. If the retrieval system has no safety unit and is directly anchored to the stopper/well tubular structure, the tool string cannot move relative to the stopper and will get stuck as in prior art solutions. Thus, in the present solution, the tool string may move/slide slightly towards the stopper with the projectable element of the anchoring section sliding along the inner surface of the safety unit 8 relative to the stopper portion when a very high force is applied, e.g. by means of a tap on the end surface 18 of the tool string, and thus the tool string may move relative to the stopper portion. The joining tool 2 is thus released from the component, i.e. the plug, because by moving downwards towards and into the plug, a shear pin or similar in the plug is broken and the joining tool is released from the plug.

The tool string is connected to the top via a cable 12, which may be a slick-line cable, an e-line cable or a conventional cable. The tool string is thus a wireline tool string, but may be connected to the surface by other means.

The safety unit 8 has an outer diameter OD larger than the tool string 1_TID of_S. The inner diameter of the safety unit may be less than 30% larger than the outer diameter of the tool, preferably less than 20% larger than the outer diameter of the tool, more preferably less than 10% larger than the outer diameter of the tool. In this way, the projectable elements of the anchoring section 6 are minimally projected.

In fig. 3, the safety unit 8 has a first unit part 14 and a second unit part 15, wherein the first unit part has said abutment surface and the inner diameter ID of the first unit part_S1Greater than the inner diameter ID of the second portion_S2And the projectable elements of the anchoring section 6 abut against the wall of the second unit part of the safety unit. In this way, the projectable element 7 need not project until abutting against the inner surface of the first unit portion, but only against the smaller second unit portion. Therefore, the temperature of the molten metal is controlled,as shown in FIG. 1, the first unit portion 14 has an abutment surface 11 and an outer diameter OD greater than the second portion_S2Larger outer diameter OD_S1。

Furthermore, by having the safety unit 8, the tool string 1 can be fitted into well tubular metal structures having different inner diameters by merely modifying/replacing the safety unit 8. Thus, the same tool string can be used for plugs pulled in a larger diameter well tubular metal structure, simply by changing the safety unit 8 to a safety unit having a larger outer diameter in the first unit part 14. Thus, the same tool string can be adapted to both larger and smaller well tubular metal structures by simply changing to a safety unit having a smaller or larger first unit part 14. The inner and outer diameters of the second unit part of the safety unit may be larger or smaller.

The safety unit provides a fixed support structure for the pipe string and can be easily modified to change diameters.

In fig. 3, the tool string 1 comprises a connection unit 34 for fastening the tool string within the safety unit 8 when the tool string and the safety unit are lowered into the well. The connection unit secures the safety unit to the tool string 1 in the axial direction and only in the upstream direction, so that when the cable is pulled, the safety unit 8 is pulled out of the well with the tool string. This is due to the fact that in the event that the tool string is unable to pull, for example, a plug, the tool string may be released by applying a strong tap to the end of the tool string closest to the surface and thus moving the tool string slightly downward to break a shear pin or similar member to release the tool string from the plug. The connection unit 34 may be an expandable member or a fixed member such as a stop mounted as part of a tool string. In fig. 3A, the reason the connection unit is fastened to the safety unit 8 is that the safety unit has a smaller inner diameter providing a flange against which the connection unit 34 abuts, and thus, the safety unit 8 is suspended on the connection unit when the tool string is run into or pulled out of the well. When the tool string is located in the well and preferably just before the safety unit 8 abuts the stop 32 or just after the safety unit 8 abuts the stop 32, the projectable elements of the anchoring section project to abut and engage the inner surface of the safety unit. The retrieval operation may then begin.

In another embodiment as shown in fig. 1, the projectable elements of the anchoring section project against and engage the inner surface of the safety unit 8 before running the tool string into the well for retrieving the plug, so that the tool string and the safety unit are firmly connected together when running them into the well without the use of further connecting means. The safety unit 8, once against the stop 32, starts the retrieval operation.

When the abutment surface 11 of the safety unit 8 rests on the stop, the connection tool 2 projects beyond the abutment surface 11 in the longitudinal extension 10 of the tool string until the connection tool is connected to a plug or similar well component 30. When the second part 5 and thus the connection tool 2 and the plug are retracted such that the plug no longer engages the well tubular metal structure, the plug need not be retracted into the first unit part 14 when the tool string and the safety unit are retracted from the well tubular metal structure 31, but may be arranged only outside the safety unit 8.

In fig. 1, each anchoring section is provided with four projectable elements 7 in the same cross-sectional plane in the direction of longitudinal extension and perpendicular to the radially outward direction, so that two of said projectable elements project radially outward in a direction opposite to the direction in which the other two projectable elements project radially outward. In fig. 3, the anchoring section has eight projectable elements 7, whereby four projectable elements 7 are arranged in a first plane and the other four projectable elements 7 are arranged in a second plane perpendicular to the first plane. The projectable element 7 may be a piston that moves in a cylinder in the tool body of the anchoring section and is projectable radially outwards under the action of pressurized fluid from a pump 23 (see fig. 3).

In fig. 2A, the safety unit 8 is a tubular sleeve having the same inner diameter and the same outer diameter along the sleeve. In fig. 2B, the safety unit 8 is also tubular and it is divided into a plurality of arms 17, each having an end face 21 facing away from the top and constituting an abutment surface. A first unit partThe inner diameter of 14 is larger than the inner diameter of the second unit portion 15, and the outer diameter of the first unit portion 14 is larger than the outer diameter of the second unit portion 15. In fig. 2C, the safety unit 8 is tubular in shape, which is a tube structure having a square cross-sectional shape with an inscribed circle representing the inner diameter, and thus, the inner diameter ID of the first unit portion 14_SLarger than the inner diameter of the second unit portion 15.

The tool string 1 may also include a cleaning tool 19 configured to expel or draw fluid to clean the contours 20 in the well member, as shown in fig. 3. The cleaning tool is arranged between the connecting tool, also called GS pulling tool, and the force generator 3 and sucks or discharges fluid via a fluid channel 22 in the connecting tool. The force generator is hydraulically driven by a pump 23 driven by a motor 24, which is powered by the cable 12 via an electrical section 25. The pump provides pressurized fluid to the anchoring section 6 and the force generator 3. The cleaning tool 19 is driven by electricity via the anchoring section 6 and the force generator 3. The cleaning tool may have a motor and a pump for pumping or discharging fluid. In another aspect of the invention, the cleaning tool is directly driven by a pump 23 that provides pressurized fluid to the anchoring section 6 and the force generator 3. Instead of having a fluid passage in the connecting means, the cleaning means 19 can also drain or suck fluid via an opening in the housing of the cleaning means.

The safety unit is made of metal or similar material with a strength to withstand the force generated by the force generator for pulling the plug without it bulging. The force generator is an axial force generator and the safety unit must have sufficient strength in the axial direction in the direction of longitudinal extension to withstand high compressive forces.

The invention also relates to a downhole system comprising a retrieval system as described above and a well tubular metal structure 31 in a borehole of a well, wherein the well tubular metal structure comprises a stopper 32 and a plug 30. The tool string of the retrieval system is arranged inside the safety unit and the tool string is secured inside the safety unit by projecting the projectable element before the retrieval system is introduced into the well tubular metal structure until the abutment surface rests on the stop. Thereafter, the second portion of the force generator is moved relative to the first portion until the connection tool engages the well component, and then the well component is pulled by retracting the second portion of the force generator to retrieve the well component. The system may further comprise a detection unit for detecting a malfunction during retrieval of the well component and thereby releasing the connection tool by providing a tapping force at the end face of the tool string.

The force generator may be a stroking tool, which is a tool that provides an axial force. The stroking means comprises an electric motor 24 for driving a pump 23. The pump pumps fluid into a piston housing in the force generator to move a piston within the piston housing. The piston is arranged in a stroke rod 26 (see fig. 3). The pump may pump fluid into the piston housing on one side and simultaneously suck fluid out on the other side of the piston to move the stroke rod or the housing of the stroke tool.

Fluid or wellbore fluid refers to any type of fluid present downhole in an oil or gas well, such as natural gas, oil-based mud, crude oil, water, and the like. Gas refers to any type of gas component present in a well, completion, or open hole, and oil refers to any type of oil component, such as crude oil, oleaginous fluids, and the like. The gas, oil and water fluids may thus each comprise other elements or substances than gas, oil and/or water, respectively.

By a casing or well tubular metal structure is meant any type of pipe, tubing, tubular structure, liner, string etc. used downhole in connection with oil or gas production.

In the event that the tool is not fully submerged in the casing, a drive unit such as a downhole tractor may be used to push the tool fully into position in the well. Downhole tractors may also be used as the anchoring section. The downhole tractor may have projectable arms with wheels, wherein the wheels contact an inner surface of the casing for advancing the tractor and the tool within the casing. Downhole tractors are any type of driving tool capable of pushing or pulling a tool downhole, e.g. Well

Although the invention has been described above in connection with preferred embodiments thereof, several variations will be apparent to those skilled in the art which may be made without departing from the invention as defined in the following claims.