Once an oil or gas well is drilled, it is often necessary for wireline logging tools, perforating devices, cutter tools, etc. to be lowered down the well with the use of a conveyance to perform logging, perforating, cutting, etc. operations.
To conduct these downhole operations, many tools require sufficiently high anchoring force to be generated. With the aid of anchoring devices, radial forces by the anchor pad generates enough friction against a wellbore to prevent sliding at the contact points between the anchor pad and the surface of the wall. Anchoring devices are usually designed to cater to a wide range of well-bore sizes, by radially expanding to accommodate the different pipe sizes during an operation. The current use of a toggle mechanism is a viable solution to most ranges of well-bore sizes. However, such a mechanism imposes a huge challenge when operations involve pipes with small diameters. The mechanical disadvantage arising from the use of a toggle mechanism causes the generation of insufficient anchoring forces, leading to operation failures.
Presently, there are alternative designs to cater to the limitations of a toggle anchor mechanism. One of such examples is based on the use of tapered surfaces known as wedges. This ensures that even at small pipe diameters, sufficiently high anchoring forces can still be achieved to carry out necessary operations. However, a key limitation to this design is the limited range of radial expansion.
Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
In the drawings and descriptions that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. The drawn figures are not necessarily to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of certain elements may not be shown in the interest of clarity and conciseness. The present disclosure may be implemented in embodiments of different forms.
Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results.
Unless otherwise specified, use of the terms “connect,” “engage,” “couple,” “attach,” or any other like term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described.
Unless otherwise specified, use of the terms “up,” “upper,” “upward,” “uphole,” “upstream,” or other like terms shall be construed as generally away from the bottom, terminal end of a well, regardless of the wellbore orientation; likewise, use of the terms “down,” “lower,” “downward,” “downhole,” “downstream,” or other like terms shall be construed as generally toward the bottom, terminal end of a well, regardless of the wellbore orientation. Use of any one or more of the foregoing terms shall not be construed as denoting positions along a perfectly vertical axis. Unless otherwise specified, use of the term “subterranean formation” shall be construed as encompassing both areas below exposed earth and areas below earth covered by water such as ocean or fresh water.
The present disclosure is based, at least in part, on the recognition that traditional toggle based anchoring mechanisms and wedge based anchoring systems each have certain limitations that make them unsuitable for a variety of different wellbore sizes. Accordingly, the present disclosure has developed an improved anchoring mechanism that can provide sufficiently high radial output forces at all wellbore sizes. The present disclosure, in at least one embodiment, describes an anchoring mechanism that integrates the two different principles into one—the wedge and toggle mechanism. At small wellbore sizes, the mechanism adopts the wedge principle, whereby the vectored forces are imparted onto the anchor pad through the direct contact area between the wedge surface and the anchor pad. At larger wellbore sizes, a transition between the two principles occurs, and the toggle mechanism takes over the wedge mechanism. The vectored forces are then imparted on the anchor pad through the linkage arms. By combining the two principles, it is possible to achieve a substantially high radial force at all wellbore sizes, which is a major advantage of the present disclosure and is markedly better than existing counterparts.
In at least one embodiment, the tapered surface engages at (e.g., directly at) the anchor pad. Further to one embodiment of the disclosure, the disclosed anchoring mechanism employing the wedge principle is capable of expanding at least 130% from its fully radially retracted state to is fully radially extended state. In yet another embodiment, the disclosed anchoring mechanism employing the wedge principle is capable of expanding at least 150% from its fully radially retracted state to is fully radially extended state, if not at least 200%, or at least 250%.
The wellbore 130 may be drilled into the subterranean formation 125 using any suitable drilling technique. In the example illustrated in
A wellbore conveyance 140 may be lowered into the wellbore 130 for a variety of drilling, completion, workover, treatment, and/or production processes, amongst others, throughout the life of the wellbore 130. The example shown in
In an example, the wellbore conveyance 140 may include a completion assembly string comprising one or more wellbore tools, which may take various forms. For example, a zonal isolation device may be used to isolate the various zones within the wellbore 130 and may include, but is not limited to, a plug, a valve (e.g., lubricator valve, tubing retrievable safety valve, fluid loss valves, etc.), and/or a packer (e.g., production packer, gravel pack packer, frac-pac packer, etc.). Coupled to the wellbore conveyance 140, in the example illustrated in
In accordance with one embodiment of the disclosure, an anchoring mechanism 160 designed, manufactured and/or operated according to one or more embodiments of the disclosure, engages with the wellbore 130 (e.g., whether directly with the wellbore 130 or the wellbore casing 132). Accordingly, the anchoring mechanism 160 may be used to fix the downhole tool assembly (e.g., perforating gun assembly 150 in the embodiment of
Turning to
Turning to
In at least one embodiment, a first end of the one or more telescoping arms 310 is coupled to one of the wedge hub 350 or the hub 370, a first end of the one or more fixed toggle arms 330 is coupled to the other of the hub 370 or the wedge hub 350, and a second end of the one or more telescoping arms 310 and a second end of the one or more fixed toggle arms 330 are coupled to one another between the first ends of the one or more telescoping arms 310 and fixed toggle arms 330. In the illustrated embodiment, each of the one or more telescopic arms 310 are connected to the one or more fixed toggle arms 330 by a first pivot point 315 (e.g., first pivot pin) on their second ends. The first ends of the one or more telescopic arms 310 are connected to the movable wedge hub 350 by a second pivot point 320 (e.g., second pivot pin). In contrast, the first ends of the one or more fixed toggle arms 330 are connected to the hub 370 by a third pivot point 325 (e.g., third pivot pin). Depending on the function of the anchoring mechanism, other elements, such as an anchor pad 380 can be joined at the first pivot point 315. Similarly, the anchoring mechanism 300 may have one or more connection points 390 (e.g., set screws) for physically coupling the wedge hub 350 to a source of an axial force (Fa), such as a sliding sleeve 395 (e.g., shown in
In at least one embodiment, the one or more telescopic arms 310 include an inner member 310a and an outer member 310b, the inner and outer members 310a, 310b configured to slide (e.g., telescope) relative to one another. In the illustrated embodiment of
Turning now to
At the start of the stroke, as shown in
As the stroke length continues to increase, the anchoring mechanism 300 will also continue to extend radially, causing the one or more telescopic arms 310 to decrease in length (e.g., causing the inner member 310a to slide within the outer member 310b). Once the anchor pad 380 contacts an inner surface that it is to engage (e.g., inner surface of the pipe, wellbore, etc.), axial forces (Fa) on the wedge hub 350 are transmitted through the contact line between the inclined surface and the anchor pad 380, and the upward force exerted by the anchor pad 380 on the surface of the inner surface acts as the anchoring force, (Fr) for the tool. It is important to note that the contact between the inclined surface and the anchor pad can be a point, line or area contact, depending on the design of the anchoring mechanism 300.
The maximum radial extension of the anchoring mechanism 300 using simply the wedge hub 350 is limited by the design constraints imposed on the anchoring mechanism 300. For example, depending on the stroke length, the size of the anchor pad 380, the length of the one or more telescopic arms 310 and one or more fixed toggle arms 330, and the angle and/or length of the inclined surface of the wedge hub 350, a maximum radial extension of the anchoring mechanism 300 using simply the wedge hub 350 is reached once the wedge hub 350 disengages from the anchor pad 380. At the same time, this engages the toggle feature, as illustrated in
As the stroke length continues to increase, the toggle mechanism becomes the principle of operation, as shown in
Turning to
Turning now to
Aspects disclosed herein include:
Aspects A, B, and C may have one or more of the following additional elements in combination: Element 1: wherein the hub is a fixed hub. Element 2: wherein the wedge hub is slidably disposed about the tubular housing. Element 3: further including an anchor pad, wherein the second end of the one or more telescoping arms and the second end of the one or more fixed toggle arms are coupled to one another proximate the anchor pad, the anchor pad configured to engage an inner surface of a wellbore tubular. Element 4: wherein the wedge hub is configured to engage the anchor pad to move the anchor pad to a first radially extended state, wherein the wedge hub is configured to then disengage from the anchor pad and the one or more telescoping arms and one or more fixed toggle arms are configured to move the anchor pad to a second further radially extended state. Element 5: further including a sliding sleeve disposed about the tubular housing, the sliding sleeve coupled with the at least one of the hub or wedge hub slidably disposed about the tubular housing, the sliding sleeve configured to slide to move the anchor pad to the first radially extended state and the second further radially extended state. Element 6: further including one or more connection points for physically coupling the sliding sleeve with the at least one of the hub or wedge hub slidably disposed about the tubular housing. Element 7: wherein the one or more telescoping arms each include an inner member and an outer member, the inner and outer members configured to telescope relative to one another. Element 8: wherein the outer member is coupled to the one of the hub or the wedge hub slidably disposed about the tubular housing and the inner member is coupled to the fixed toggle arm. Element 9: wherein the hub is a fixed hub and the wedge hub is slidably disposed about the tubular housing. Element 10: further including an anchor pad, wherein the second end of the one or more telescoping arms and the second end of the one or more fixed toggle arms are coupled to one another proximate the anchor pad, the anchor pad configured to engage an inner surface of a wellbore tubular, and further wherein sliding the at least one of the hub or wedge hub about the tubular housing causes the anchor pad to engage an inner surface of the wellbore. Element 11: wherein the wedge hub is configured to engage the anchor pad to move the anchor pad to a first radially extended state, wherein the wedge hub is configured to then disengage from the anchor pad and the one or more telescoping arms and one or more fixed toggle arms are configured to move the anchor pad to a second further radially extended state. Element 12: further including a sliding sleeve disposed about the tubular housing, the sliding sleeve coupled with the at least one of the hub or wedge hub slidably disposed about the tubular housing, the sliding sleeve sliding to move the anchor pad to the first radially extended state and the second further radially extended state. Element 13: further including one or more connection points for physically coupling the sliding sleeve with the at least one of the hub or wedge hub slidably disposed about the tubular housing. Element 14: wherein the one or more telescoping arms each include an inner member and an outer member, the inner and outer members configured to telescope relative to one another. Element 15: wherein the outer member is coupled to the one of the hub or the wedge hub slidably disposed about the tubular housing and the inner member is coupled to the fixed toggle arm. Element 16: further including an anchor pad, wherein the second end of the one or more telescoping arms and the second end of the one or more fixed toggle arms are coupled to one another proximate the anchor pad, the anchor pad configured to engage an inner surface of a wellbore tubular. Element 17: wherein the wedge hub is configured to engage the anchor pad to move the anchor pad to a first radially extended state, wherein the wedge hub is configured to then disengage from the anchor pad and the one or more telescoping arms and one or more fixed toggle arms are configured to move the anchor pad to a second further radially extended state.
Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments.
This application claims the benefit of U.S. Provisional Application Ser. No. 63/335,762, filed on Apr. 28, 2022, entitled “DOWNHOLE ANCHOR SYSTEM,” commonly assigned with this application and incorporated herein by reference in its entirety.
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WIPO Written Opinion (Year: 2023). |
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Number | Date | Country | |
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63335762 | Apr 2022 | US |