WO2021071362A1

WO2021071362A1 - A slotted tubular remediation tool and method

Info

Publication number: WO2021071362A1
Application number: PCT/NO2020/050228
Authority: WO
Inventors: Morten Lerbrekk; Ove LERBREKK
Original assignee: Tyrfing Innovation As
Priority date: 2019-10-10
Filing date: 2020-09-08
Publication date: 2021-04-15

Abstract

A remediation tool (1) configured for deployment into a downhole slotted liner (10) comprises a body (20) and actuation means (7, 5, 9a,b, 40), and one or more radial displacement members (30) connected to the body and configured to move radially. The displacement members may exert a force on at least a portion of the tubular wall and controllably deform said portion of the tubular wall, whereby the slots are widened.

Description

A slotted tubular remediation tool and method Technical field of the invention

The invention concerns a device for maintaining and remediating slotted tubulars, as set out by the preamble of claim 1, and a method of removing one or more objects from an opening in the wall of a tubular, as set out by the preamble of claim 10.

Background of the invention

So-called slotted liners are commonly used in the completion of subterranean boreholes, for example boreholes in subterranean hydrocarbon wells. They may be installed across the reservoir section for hole stability (well construction) and sand control reasons. A slotted liner may be nested inside a previously installed casing, or may be installed in an open-hole well. The slotted liner is normally gravel-packed and designed to hold back the gravel pack sand, while allowing the formation fines to pass through.

In general, a slotted liner typically comprises a tubular (e.g. a pipe) having a plurality of openings (slots) formed in its wall. The slots are elongated openings (in the liner axial direction), formed for example by saw-cutting, and may be arranged at a number of different orientations and patterns (e.g. straight slots, staggered slots, gang-staggered slots). The slots are dimensioned according to its intended use and anticipated particle size. Typical slot widths may be in the range from 0.3 mm to 1.0 mm, but may be larger or smaller. To avoid initial sand production, slot size (width) is often chosen conservatively, which reduces production potential. Slots may have the same dimensions on the outside and the inside of the liner (i.e. a straight channel through the liner wall) or the slots may be narrower on the outside than on the inside of the liner (i.e. a funnel-shaped channel, referred to as “keystone” shape). Although the latter configuration is less prone to clogging (i.e. plugging), a general problem with all slotted liners is that the slots tend to become plugged by particles (e.g. formation sand). As a slotted liner at the outset has a relatively small inflow area (e.g. 2 - 3%), a further inflow limitation due to slot plugging may significantly reduce the production potential.

Several tools and methods exist for cleaning and remediating (i.e. removing particles plugging the slots) a slotted liner, either mechanically, chemically or hydraulically. The prior art includes US 2464 669, which describes a tool configured for being arranged inside a slotted liner, and having a plurality of blades that may be pivoted and extended through respective slots in the liner. A blade may thus remove particles or other obstacles lodged in the slot, simply by the mechanical action of pushing the particle (or particles) back into the annulus between the liner and the casing. The efficiency of this tool depends on the alignment between a blade and a slot. It is therefore a need for a more efficient mechanical device and method for remediating a slotted liner.

Summary of the invention

The invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention. It is thus provided a slotted tubular remediation tool for deployment into a slotted tubular, said tool comprising a body and actuation means, and characterized by one or more radial displacement members connected to the body and configured to move radially inside the slotted tubular and exert a force on at least a portion of the slotted tubular wall and controllably deform said portion of the tubular wall. The actuation means may comprise at least an axial displacement member, movably arranged in the tool and arranged and dimensioned to exert a radial force on the radial displacement members. The axial displacement member may comprise a frusto-conical shape and be movable on a rod extending along the tool longitudinal axis. The displacement member may be hydraulically actuated. In one embodiment, the radial displacement members are elongated members, secured at a first end to the body, extending along the tool longitudinal axis, and having a second, free, end. The axial displacement member may be arranged adjacent to the radial displacement members’ second, free, end when the tool is in an unactuated state. The axial displacement member may be arranged radially inside of the radial displacement members when the tool is in an actuated state.

The tubular may comprise a plurality of wall openings having a length dimension in the tubular axial direction, and the displacement member movable portion length is greater than the wall opening length. In one embodiment, the displacement member movable portion length is greater than the wall opening length by at least a factor of two. It is also provided a method of removing one or more objects from at least one wall opening in the wall of a tubular, characterized by applying a force, internally in the tubular, to a portion of the wall of the tubular in the region of the opening in order to enlarge the opening. In one embodiment, the force is applied uniformly around the tubular wall circumference. The force may be applied by the invented slotted tubular remediation tool.

The slotted tubular may be a slotted liner and the tool may be used to increase the widths of slots in a slotted lined installed in a subterranean wellbore.

Brief description of the drawings These and other characteristics of the invention will become clear from the following description of an embodiment of the invention, given as a non-restrictive example, with reference to the attached schematic drawings, wherein:

Figure 1 shows two side views of an embodiment of the invented slotted tubular remediation tool in an unactuated state, where figure la is a view in the section A-A along the longitudinal axis CL of figure lb;

Figures 2 and 3 are enlarged views of the areas marked Ei and E₂ in figure 1, respectively;

Figure 4 corresponds to figure 1, but show the invented slotted tubular remediation tool in an actuated state, and where figure 4a is a view in the section B-B along the longitudinal axis CL of figure 4b;

Figures 5 and 6 are enlarged views of the areas marked E₃ and E₄ in figure 1, respectively;

Figures 7 and 8 are enlarged views of a portion of an embodiment of the invented slotted tubular remediation tool arranged inside a tubular liner, in an unactuated state and an actuated state, respectively; and

Figure 9 is a perspective view of a section of a slotted tubular (e.g. a slotted liner), indicating a section of the tubular which has been expanded radially by the invented tool. Detailed description of embodiments of the invention

The following description may use terms such as “horizontal”, “vertical”, “lateral”, “back and forth”, “up and down”, ’’upper”, “lower”, “inner”, “outer”, “forward”, “rear”, etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader’s convenience only and shall not be limiting.

Reference is initially made to figures 1, 2, 3, and 7, which all illustrate an embodiment of the invented slotted tubular remediation tool 1 in an unactuated state, i.e. the state in which the tool is deployed into, and subsequently retrieved from, the downhole liner The tool 1 comprises a generally cylindrical body 20, to which is connected a rod 8 which terminates in an end cap 4. The tool body 20 is configured for connection to a control and deployment device (not shown), via a connection assembly 22. The skilled person will understand that the tool 1 may be deployed, actuated and retrieved by means and methods well known in the art. Arranged around the rod 8 is a cone assembly 40, a cylinder assembly 6, and a cylindrical housing 2, all movable along the rod 8. A piston assembly 5 is fixed to the rod 8 by known means (e.g. screws; not shown). A hydraulic line 7 extends along the rod 8 interior, from a fluid port 21 and to a first chamber 9a on one side (the “body side”) of the piston assembly 5 and to a second chamber 9b on the other side (the “end cap side”) of the piston assembly 5. When a fluid is injected into the first volume 9a, the cone assembly 40, cylinder assembly 6 and the cylindrical housing 2 are displaced as one unit along the rod 8 (which is aligned with the tool longitudinal axis CL) towards the body 20. Conversely, when a fluid is injected into the second volume 9b, the cone assembly 40, cylinder assembly 6 and the cylindrical housing are displaced as one unit along the rod 8 towards the end cap 4. Such configuration, including required control valves and check valves (not shown) is well known, and needs therefore not be described further here. Also, required seals and gaskets are not illustrated, for simplicity of illustration. It should be understood that other axial movements mechanisms may be equally applicable; the cone assembly 40 may for example be moved by a powered jack screw. Referring in particular to figure 2, a plurality of elongated members, hereinafter referred to as “fingers”, 30 are attached to the body 20. The number and widths of fingers may be varied, for example depending on the tool outer diameter. Each finger 30 is attached at one end to the body 20 by known means (e.g. screws) 3. In the illustrated embodiment, the other end of each finger is a free end (not attached) but is bearing against a forward (in the drawing: upper) portion of the cone assembly 40 by virtue of its stiffness. The active (i.e. movable) length of each finger 30 is indicated by reference sign If. The fingers 30 comprise a hard, elastic material, for example a hardened steel.

The cone assembly 40 comprises an outer surface having a frusto -conical shape, with a region of maximum diameter R. The cone region of maximum diameter R is not greater than the tool housing outer diameter OD. The cone and fingers are formed of a material which is harder than the liner material.

Figure 7 illustrates a portion of the invented tool 1 installed in a portion of a slotted tubular (e.g. a liner) 10. Although the slots are not shown in this figure, reference sign l_s indicates the length of a slot. It will be understood that the length of the fingers (see If in figures 2 and 9) is considerably greater than the slot length l_s. This ensures that the force applied by the fingers is distributed over large portion of the tubular wall, whereby the friction between the fingers and the wall is low and stress hotspots are avoided. The finger length k is at least twice the slot length l_s, preferably three times longer than the slot length. The tool outer diameter (OD) is slightly less than the diameter of the slotted tubular 10, such that the tool in the unactuated state fits snugly inside the tubular. Reference is now made to figures 4, 5, 6, and 8, which all illustrate an embodiment of the invented remediation tool 1 in an actuated state, i.e. the state in which the tool 1 is performing its remediation operation to increase the slot dimensions (primarily the widths) in the tubular wall. Here, the cone assembly 40 has been moved towards the body 20 along the rod 8 by injection of a fluid into the second chamber 9b. This axial movement of the cone assembly 40 leads to a radial displacement of the fingers 30. The magnitude of the radial displacement is determined by the diameter at the above- mentioned region of maximum diameter R.

Figure 8 illustrates the effect of the cone assembly’s axial movement and the fingers’ radial displacement: The wall of the slotted tubular 10 is forced radially outwards, a radial distance e, as indicated in figure 8. This radial expansion of the tubular wall leads to an expansion and enlargement of the slots, for example by between 20% and 100%. hi most cases, the portion of the slotted tubular which is exposed to the finger action is expanded beyond its yield point and thus permanently (plastically) deformed. An elastic (non-permanent) deformation is, however, also conceivable. It should be understood that the cone assembly may be extended and retracted multiple times, if necessary, before the tool is placed in the unactuated state and moved to another location inside the tubular, or retrieved to the surface. Figure 9 illustrates a section of a slotted liner 10, and shows how a section of the liner has been expanded radially by the invented tool 1. The figure shows that the slots 12 in the expanded section are larger (here: wider) than the slots 11 in the original (unexpanded) section. Because the movable length If of each finger 30 is considerably longer than the length l_s of each slot 12, a plurality of slots may be remediated simultaneously.

The invented tool is robust and reliable, and may be activated an unlimited number of times. The tool provides a controlled and predictable slot width increase, as the cone diameter may dimensioned to suit the intended slot width increase.

Although the invention has been described with reference to a slotted liner, it should be understood that the invented remediation tool is useful for expanding also other tubulars.

Although the invention has been described with reference to wall openings in the shape of slots, the invention is equally applicable for use in expanding wall openings having other geometrical shapes, for example, square, oval, polygonal.

In the embodiments described above, various features and details are shown in combination. The fact that several features are described with respect to a particular example should not be construed as implying that those features by necessity have to be included together in all embodiments of the invention. Conversely, features that are described with reference to different embodiments should not be construed as mutually exclusive. As a person skilled in the art readily will understand, embodiments that incorporate any subset of features described herein and that are not expressly interdependent have been contemplated by the inventor and are part of the intended disclosure. However, explicit description of all such embodiments would not contribute to the understanding of the principles of the invention, and consequently some permutations of features have been omitted for the sake of simplicity or brevity.

Claims

1. A slotted tubular remediation tool ( 1 ) for deployment into a slotted tubular (10), comprising a body (20) and actuation means (7, 5, 9a, b, 40), and characterized by one or more radial displacement members (30) connected to the body and configured to move radially inside the tubular and exert a force on at least a portion of the tubular wall and controllably deform said portion of the tubular wall.

2. The tool of claim 1, wherein the actuation means comprises at least an axial displacement member (40), movably arranged in the tool and arranged and dimensioned to exert a radial force on the radial displacement members (30).

3. The tool of claim 2, wherein the axial displacement member (40) comprises a frusto-conical shape and is movable on a rod (8) extending along the tool longitudinal axis (CL).

4. The tool of any one of claims 2-3, wherein the displacement member is hydraulically actuated.

5. The tool of any one of claims 2-4, wherein said one or more radial displacement members (30) are elongated members, secured at a first end to the body (20), extending along the tool longitudinal axis (CL), and having a second, free, end, and a movable portion of a length (If).

6. The tool of claim 5, wherein the axial displacement member (40) is arranged adjacent to the radial displacement members’ (30) second, free, end when the tool is in an unactuated state.

7. The tool of claim 6, wherein the axial displacement member (40) is arranged radially inside of the radial displacement members (30) when the tool is in an actuated state.

8. The tool of any one of claims 5-7, wherein the tubular (10) comprises a plurality of wall openings (11) have a length dimension (l_s) in the tubular axial direction, and the displacement member (30) movable portion length (If) is greater than the wall opening (11) length (l_s).

9. The tool of claim 8, wherein h is greater than l_s by at least a factor of two.

10. A method of removing one or more objects from at least one wall opening (11) in the wall of a tubular (10), characterized by applying a force, internally in the tubular, to a portion of the wall of the tubular in the region of the opening in order to enlarge the opening.

11. The method of claim 10, wherein the force is applied uniformly around the tubular wall circumference.

12. The method of claim 10 or claim 11, wherein the force is applied by the tool as defined by any one of claims 1-9.