Mechanical centralizers are used in conjunction with in-ground drilled holes in the underground drilling and geotechnical construction industries. Their role is to ensure that fluids, grouts or other cementitious materials are evenly distributed around a central object. Extant centralizers are one type of centralizer that is mechanically fixed to the object being centralized, typically a drilling stem, hole casing, pipe, or reinforcing element. Extant centralizers may use a mechanical linkage system to either release spring tension or apply stress to some portion of the centralizer to maintain its longitudinal hole position.
There is nevertheless a benefit to improving the designs and configurations of centralizers.
An exemplary in-ground bow spring centralizer device, system, and method of use thereof are disclosed that, once placed in an underground drilled hole, is configured to provide spring tension to resist translation of the centralizer along the axis of that drilled hole, absent external mechanical effort, by applying stress to the exterior walls of the hole and/or penetrating into the soil surrounding the drilled hole. The resistance to translation is especially pronounced opposite the installation direction as a result of the snake-skin-inspired directionally varying surface of the centralizer. This allows the centralizer to remain longitudinally in place without a mechanical connection to the object being centralized, enabling sliding and rotational translation of the centralized object within the centralizer while the latter remains in place.
According to one aspect of the disclosure, an in-ground mechanical bow spring centralizer device is disclosed (e.g., for locating within a drilled hole, or guiding the installation of a tube or tendon in a drilled hole). The centralizer device includes a body collar, a tail collar, a body, and a tail. The body collar extends circumferentially around a central axis and defines a longitudinal channel. The central axis extends from an up-hole direction of the centralizer device towards a downhole direction of the centralizer device. The tail collar extends circumferentially around the central axis to further define the longitudinal channel. The tail collar is spaced apart from the body collar in the up-hole direction of the centralizer device. The body extends between the body collar and the tail collar. The body includes a first portion coupled to the body collar, a second portion coupled to the tail collar, and a bow portion coupled to and between the first portion and the second portion. The bow portion extends radially outward from the central axis to define at least one apex. The body further defines at least one opening. The tail extends (i) longitudinally from the tail collar or the body collar and (ii) radially outward from the central axis. The tail includes a tail tip at a distal end thereof.
In some implementations, the tail extends longitudinally from the tail collar in the up-hole direction. In some implementations, the tail tip extends further radially outward than the at least one apex of the bow portion of the body. In some implementations, the tail tip extends radially outward from the central axis the same distance as the at least one apex of the bow portion of the body extends radially outward from the central axis. In some implementations, the at least one apex of the bow portion of the body extends further radially outward than the tail tip.
In some implementations, the body includes a plurality of body sections, including a first body section and a second body section. In some implementations, the first body section and the second body section are equally circumferentially spaced apart from each other.
In some implementations, the tail includes a plurality of tail sections, including a first tail section and a second tail section that are equally circumferentially spaced apart from each other.
In some implementations, the body and the tail are flexible such that one or both of the body and the tail are radially compressible and expandible during operation.
In some implementations, the tail tip is angled such that (i) during movement of the centralizer device in the downhole direction of a hole (e.g., an insertion operation), the tail tip does not penetrate a surrounding substrate of the hole, and (ii) during movement of the centralizer device in the up-hole direction of the hole (e.g., an extraction operation), the tail tip penetrates the surrounding substrate to resist movement in the up-hole direction.
In some implementations the tail tip is flexible and, when penetrating the surrounding substrate, the tail tip flexes to move (i) radially outward from the central axis and (ii) longitudinally toward the downhole direction with respect to the tail collar.
In some implementations, the centralizer device is configured to allow longitudinal translation and rotational translation of a centralized object that is disposed within the longitudinal channel relative to the centralizer device.
According to another aspect, a system is disclosed, the system including an in-ground mechanical bow spring centralizer device and an installation tube. The in-ground mechanical bow spring centralizer device includes: a body collar extending circumferentially around a central axis and defining a longitudinal channel, the central axis extending from an up-hole direction of the centralizer device towards a downhole direction of the centralizer device; a tail collar extending circumferentially around the central axis to further define the longitudinal channel, the tail collar spaced apart from the body collar in the up-hole direction of the centralizer device; a body extending between the body collar and the tail collar, the body including a first portion coupled to the body collar, a second portion coupled to the tail collar, and a bow portion coupled to and between the first portion and the second portion, the bow portion extending radially outward from the central axis to define at least one apex, wherein the body further defines at least one opening; and a tail extending (i) longitudinally from the tail collar and (ii) radially outward from the central axis, the tail including a tail tip at a distal end thereof. The installation tube includes an outer tube surface and a catch disposed on and protruding from the outer tube surface, wherein the catch engages with one or both of the body collar and the tail collar.
In some implementations, the catch is a first catch, the installation tube further including a second catch spaced apart from the first catch. In some implementations, the first catch engages with the up-hole end of the tail collar through a tail opening defined by the tail, and the second catch extends through the at least one opening of the body to engage with the up-hole end of the body collar.
In some implementations, in an advancing configuration, an extent of the second catch engaging the body collar is disposed outside of the longitudinal channel and the installation tube is disposed inside the longitudinal channel radially adjacent to either the tail collar, the body collar, or the body. In some implementations, in a retracting configuration, the second catch is disposed inside the longitudinal channel and does not contact nor engage with the tail collar, the body collar, or the body, wherein the installation tube is free to retract out of the centralizer device.
In some implementations, the installation tube is disposed within the longitudinal channel of the centralizer device, and both the centralizer device and the installation tube are installed in an underground hole. In some implementations, the centralizer device is configured to use spring tension to resist deviation from an axis of the underground hole by applying stress to an exterior wall of the underground hole and/or penetrating a substrate of the underground hole. In some implementations, the catch of the installation tube engaging with the centralizer device applies a downhole force to the centralizer device to facilitate installation.
Additional advantages will be set forth in part in the description which follows or may be learned by practice. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive, as claimed.
Various objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the detailed description taken in conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.
Referring generally to the figures, an in-ground mechanical bow spring centralizer is shown, according to various implementations. Disclosed herein are various implementations of an in-ground mechanical bow spring centralizer which, once placed in an underground drilled hole, uses the spring tension and geometry of its partial bow section to resist translation along the axis of that hole absent external mechanical effort by applying stress to the exterior walls of the hole and/or penetrating into the soil surrounding the drilled hole. The resistance to translation is especially pronounced opposite the installation direction. This allows the centralizer to remain in place without a mechanical connection to the object being centralized, enabling sliding and rotational translation of the centralized object within the centralizer while the latter remains in place.
The centralizer device 100 includes a body collar 110, a tail collar 120, a body 130, and a tail 150. The body collar 110 extends circumferentially around the central axis 101. The body collar 110 includes a first end 112 and a second end 114 opposite and spaced apart from the first end 112. The body collar 110 further includes an inner surface 116 and an outer surface 118 opposite from the inner surface 116. Each of the inner surface 116 and the outer surface 118 extend between the first end 112 and the second end 114 of the body collar 110.
The inner surface 116 of the body collar 110 defines a portion of a longitudinal channel 106. The longitudinal channel 106 extends from near the first end 102 of the centralizer device 100 towards the second end 104 of the centralizer device 100 along the central axis 101.
The tail collar 120 extends circumferentially around the central axis 101. The tail collar 120 includes a first end 122 and a second end 124 opposite and spaced apart from the first end 122. The tail collar 120 further includes an inner surface 126 and an outer surface 128 opposite from the inner surface 126. Each of the inner surface 126 and the outer surface 128 extend between the first end 122 and the second end 124 of the tail collar 120. The inner surface 126 of the tail collar 120 further defines a portion of the longitudinal channel 106.
The body 130 extends between the body collar 110 and the tail collar 120. The body 130 includes a first portion 132 coupled to the body collar 110, a second portion 134 coupled to the tail collar 120, and a bow portion 136 coupled to and extending between the first portion 132 and the second portion 134. Specifically, the first portion 132 is coupled to and extends from the second end 114 of the body collar 110, and the second portion 134 is coupled to and extends from the first end 122 of the tail collar 120. In some implementations, the first portion, second portion, and bow portion are integrally formed with each other and/or with the body collar and the tail collar.
The bow portion 136 extends radially outward from the central axis 101 to define at least one apex 138. As shown in
As shown, the first portion 132 extends away from the body collar 110 both longitudinally towards the tail collar 120 and radially outward from the central axis 101. Similarly, the second portion 134 extends away from the tail collar 120 both longitudinally towards the body collar 110 and radially outward from the central axis 101. Thus, while the bow portion 136 is disposed radially outward from each of the body collar 110, the tail collar 120, and the first portion 132 and the second portion 134 of the body 130, the first and second portions 132, 134 may also have curvature radially outward.
The body 130 shown in
The body 130 shown in
Each opening 140a-140d extends between adjacent body sections 130a-130d and between the body collar 110 and the tail collar 120. Thus, the body collar 110 and the tail collar 120 define the longitudinal margins of the openings 140a-140d.
The tail 150 extends from the second end 124 of the tail collar 120, away from the body collar 110 (e.g., in the up-hole direction). Specifically, the tail 150 extends longitudinally from the tail collar 120 and radially outward from the central axis 101. The tail 150 terminates in a tail tip 152 on a distal end of the tail 150. In other implementations, the tail 150 may be coupled to and extend from the body collar 110.
The tail 150 extends radially outward from the central axis 101 to define a tail diameter. In the centralizer device 100 in
Similar to the body 130, the tail 150 includes four tail sections 150a, 150b, 150c, and 150d, each substantially similar to each other. However, in other implementations, the centralizer device 100 may include a single tail section, two tail sections, three tail sections, or a plurality of tail sections greater than four (e.g., 5, 6, 7, 8, 9, 10, 20, 30, 40, or 50 tail sections). The tail sections 150a-150d are equally circumferentially spaced apart from each other. However, in other implementations, the tail sections may be spaced apart unevenly or in a pattern.
In use, the centralizer device 100 may be installed in a hole (e.g., to locate or guide installation of a tube or tendon in a drilled hole). The body 130 and tail 150 are flexible such that one or both of the body and the tail are radially compressible (e.g., to a smaller body diameter and/or tail diameter) and expandable during operation or installation. In other implementations, one or more of the body and the tail are rigid, non-flexible structures which maintain their respective diameters.
The installation tube 10 includes an outer tube surface 12 and a catch 14 disposed on and protruding from the outer tube surface 12. The catch 14 is configured to engage with either the body collar 110 or the tail collar 120 (or both) of the centralizer device 100. As shown in
In the advancing configuration shown in
In the retracting configuration shown in
In the first panel of
The exemplary centralizer may be employed in various applications. One example is in a ground anchor. An example of a ground anchor system is described in PCT Publication Number WO 2021/202944 entitled “Ground Anchoring Apparatus and Method,” which is hereby incorporated by reference in its entirety.
Regarding the drilled holes and the surrounding substrate within which the centralizer device is installed: Passive or “Bearing” resistance of soil and rock is substantially higher and more reliably developed than frictional resistance, which can be quite low and is highly dependent on the exact condition of the interface between materials and presence of lubricants such as water, grouts, and drilling fluids. Thus, a centralizer which relies on passive resistance will be more reliable than one which relies on frictional resistance alone to prevent movement. Since centralizers are used to guarantee the position of an object within a hole, enhanced reliability is inherently valuable. Snakeskin inspired centralizers (e.g., those of this disclosure) develop little or no passive resistance during insertion but an amount sufficient to prevent movement of the centralizer during extraction of centralized objects.
In implementations wherein the tail tip 152 is flexible, when penetrating the surrounding substrate, the tail tip 152 flexes to move (i) radially outward from the central axis 101 and (ii) longitudinally toward the downhole direction with respect to the tail collar 120. In some implementations of the present disclosure, the “tail” of the centralizer device may be replaced by, or supplemented with, a “fin” or “fin array”. For the purposes of the force diagrams of
As a comparison,
In the longitudinal configuration, the flexible body members 332 are expanded such that the first collar 310 is spaced apart from the second collar 320 by a maximum distance. The longitudinal configuration is a minimal diameter condition for the centralizer device 300, and it may be used upon insertion of the centralizer device 300 into a hole.
In the radial configuration, the flexible body members 332 are contracted towards each other and expanded radially outward. The first collar 310 and the second collar 320 are spaced apart by a minimal distance. The radial configuration is a maximal diameter condition for the centralizer device 300, and it may be used to resist extraction of the centralizer device 300 (e.g., once the centralizer device 300 is in place in the hole).
The main body 502 generally defines an internal bladder configured to couple to a fluid source. The centralizer device 500 in
A retaining ring 610 is pre-installed around the tail section 608 to retain the tail section 608 radially inward (e.g., during installation), as shown in
The construction and arrangement of the systems and methods as shown in the various implementations are illustrative only. Although only a few implementations have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative implementations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the implementations without departing from the scope of the present disclosure.
Although the figures show a specific order of method steps, the order of the steps may differ from what is depicted. Also, two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.
It is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or to particular compositions. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting.
As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another implementation includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal implementation. “Such as” is not used in a restrictive sense, but for explanatory purposes.
Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific implementation or combination of implementations of the disclosed methods.
This application claims priority to U.S. Provisional Patent Application No. 63/467,504, filed May 18, 2023, which is incorporated herein by reference in its entirety.
This invention was made with government support under grant no. EEC-1449501 awarded by the National Science Foundation. The government has certain rights in the invention.
Number | Date | Country | |
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63467504 | May 2023 | US |