Patent Application
20150047856
Oilfield tubulars, such as pipes, drill strings, casing, tubing, etc., may be used to transport fluids or to produce water, oil, and/or gas from geologic formations through wellbores. In various applications, a shoulder may be formed on an exterior of the tubular, e.g., for gripping the tubular and/or for connecting tools, such as centralizers, scrapers, cement baskets, etc. to the exterior of the tubular.
A variety of structures are employed to provide such shoulders. In some cases, integral parts of the tubular itself, such as expanded diameter sections, e.g., pipe joints at an end of the tubular, may be employed as the shoulder. In other cases, especially when a shoulder is needed between the ends of the tubular, a separate stop collar is generally fixed in position around the tubular to provide the shoulder. Such stop collars generally include a metal ring, which is either slid over an end of the tubular or hinged so as to receive the tubular laterally.
To fix the position of the stop collar on the tubular, the stop collars generally employ a gripping feature that engages the tubular. Such gripping features often include adhesives and/or marking structures, such as teeth or set screws. However, for some tubulars and/or applications thereof, marking the tubular may not be appropriate, either because marking the tubular damages the tubular or is otherwise incompatible with the application, or because the tubular may be too hard for marking structures to adequately bite into the tubular, resulting in inadequate holding forces. Adhesives, although suitable in a variety of stop collar applications, may lack sufficient durability or bonding strength to alone provide sufficient holding force.
Embodiments of the disclosure may provide a stop collar for a tubular. The stop collar includes a flexible member extending circumferentially around the tubular more than once. A tension force on the flexible member causes the flexible member to apply a radially-inward gripping force on the tubular. The stop collar may also include a shield disposed around at least a portion of the flexible member, to protect the flexible member in a downhole environment.
Embodiments of the disclosure may also provide a method for installing a stop collar on a tubular. The method includes wrapping a flexible member more than once around a tubular, and applying a tension to the flexible member such that the flexible member applies a radially-inward gripping force on the tubular.
Embodiments of the disclosure may further provide an apparatus for securing to a tubular. The apparatus includes a helical flexible member positioned around a tubular, such that the flexible member applies a radially-inward gripping force on the tubular. The flexible member defines a plurality of turns around the tubular that are adjacent in a direction that is parallel to a central axis of the tubular. The apparatus also includes a layer of adhesive interposed between at least a portion of the flexible member and the tubular.
The invention may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. In the drawings:
The following disclosure describes several embodiments for implementing different features, structures, or functions of the invention. Embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference characters (e.g., numerals) and/or letters in the various embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed in the Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the embodiments presented below may be combined in any combination of ways, e.g., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Additionally, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. In addition, unless otherwise provided herein, “or” statements are intended to be non-exclusive; for example, the statement “A or B” should be considered to mean “A, B, or both A and B.”
In particular,
In other embodiments, the shield 104 may be or include a plastic, composite, metallic, etc. member, that may be disposed at least partially around the flexible member 110. The shield 104 may be selected, for example, so as to exhibit material properties suitable for exposure to the downhole environment and running-in along with the tubular 102. Such material properties may include low friction, high strength, and/or the like. Further, the stop collar 100 may have two axial ends 106, 108, which may, in at least one embodiment, be defined by the shield 104, as shown. One or both of the axial ends 106, 108 may extend straight in a radial direction from the tubular 102 and/or may be tapered, beveled, rounded, or otherwise shaped.
Further, the shield 104 may extend entirely over the stop collar 100, as shown, may extend partially thereabout, and/or may or may not extend radially inward into contact with the tubular 102. In some embodiments, a plastic, elastomeric, composite, metallic, etc. sleeve may be positioned over the shield 104, e.g., with the shield 104 providing an adhesive coupling the sleeve to a remainder of the stop collar 100.
Referring now specifically to
In such a helically-wrapped embodiment of the flexible member 110, the flexible member 110 may define turns 112 (e.g., 360 degree increments) around the tubular 102. Successive turns 112 may be adjacent to one another, generally in an axial direction along the tubular 102. In one, some, or all of the turns 112, the flexible member 110 may abut the flexible member 110 contained in at least one adjacent turn 112. As such, the flexible member 110 may form a generally continuous surface that is spaced radially apart from the tubular 102.
The shield 104 may be positioned (e.g., applied) at least partially on the exterior (radial outside, facing away from the tubular 102) of the flexible member 110, so as to protect the flexible member in the downhole environment. When provided as an adhesive coating, for example, the shield 104 may be rolled, brushed, or otherwise applied to the flexible member 110. In some embodiments, the shield 104 may be applied such that it extends axially past the first and last turns 112, so as to form the ends 106, 108, as noted above and shown in
Furthermore, in at least one embodiment, an adhesive, which may or may not be formed from the same material as the shield 104, may be positioned radially between the flexible member 110 and the tubular 102, as will be described in greater detail below. In addition, the shield 104 may extend radially past (or through) the flexible member 110, between the ends 106, 108, and into engagement with the tubular 102. For example, the shield 104 may extend through spaces defined between the turns 112. Additionally or alternatively, holes may be formed in the flexible member 110, so as to allow traversal of the flexible member 110 by the shield 104.
The flexible member 110 may be an elongate member, which may be or include a monolithic or braided cable, wire, ribbon, string, cord, line, rope, band, tape, coil spring, multi-strand wire, wire rope and any member having the flexibility and strength to be wrapped about the outer surface of the tubular 102. For example, the flexible member 110 may constructed from a metal, plastic, composite, or any combination thereof. In one embodiment, the flexible member 110 includes a steel cable, e.g., a stainless steel cable. Further, the flexible member 110 may be one unitary length of material, e.g., a length providing a desired holding force once it is wrapped (and/or adhered) on the oilfield tubular. In other embodiments, the flexible member 110 may include multiple segments that are attached together (e.g., end-on-end).
Further, a layer 208 may be applied to the tubular 102, e.g., at least partially between the inboard sides 204, 206 of the collars 200, 202. The layer 208 may be or include an adhesive, such as an epoxy, glue, resin, polyurethane, cyanoacrylate, acrylic polymer, hot melt adhesive, contact adhesive, reactive adhesive, light curing adhesive, low temperature metal spray, metal spray (such as WEARSOX®), combinations thereof, and/or the like. The layer 208 may be employed to increase the holding force provided by the stop collar 100, avoid the flexible member 110 biting into the tubular 102, and/or the like. The layer 208 may coat the tubular 102 entirely between the installation collars 200, 202 or, in other embodiments, may include axially and/or circumferentially-extending gaps.
Before or after the layer 208 is cured (e.g., when using an adhesive for the layer 208), a first turn 112 of the flexible member 110 may be disposed around the tubular 102, between the installation collars 200, 202, e.g., proximal to the installation collar 200, and on the layer 208. The first turn 112 may include the end 114-1 of the flexible member 110. Further, the end 114-1 may be secured in place, such that it is generally stationary relative to the tubular 102 during installation. For example, the end 114-1 may be held in place, with tension applied to the flexible member 110, and the end 114-1 welded to a second turn 112 of the flexible member 110. In other embodiments, the flexible member 110 may be adhered to itself near the end 114-1, clamped or fastened to itself, or the like. In other embodiments, the end 114-1 of the flexible member 110 may be secured to the installation collar 200, which may be secured against rotation. In other embodiments, a section of the flexible member 110 proximal to the end 114-1 may be turned, e.g., toward an axial direction, and held temporarily in place while one or more additional turns 112 of the flexible member 110 are received over the end 114-1.
Referring now to
In some embodiments, applying the layer 208 and wrapping the flexible member 110 may be an iterative process. For example, a certain width, e.g., less than the distance between the installation collars 200, 202, of the layer 208 may be applied onto the tubular 102, and then the flexible member 110 may be wrapped over that width of the layer 208. Then, another width of the layer 208 may be applied, and then flexible member 110 wrapped over that width. This process may repeat one or more times. In other embodiments, the layer 208 may be applied to the extent needed (e.g., all or a portion of the width between the installation collars 200, 202), and then the flexible member 110 may be wrapped around the tubular 102 continuously.
As shown in
In addition, in at least some embodiments, two or more adjacent turns 112 may be welded, adhered, or otherwise secured together. For example, as shown, several welds 210 may be created, attaching together the turns 112. Such welding (and/or otherwise attaching) together the turns 112 may further serve to retain the position of the flexible member 110.
Referring to
In some embodiments, e.g., due to the helical shape of the flexible member 110, a space may be defined between the ends of the flexible member 110 and the inboard sides 204, 206 of the installation collars 200, 202. This space may be filled with the shield 104, so as to provide the axial ends 106, 108 with a generally annular shape. Further, in some cases, the ends of the flexible member 110 may not contact the collars 200, 202, and thus the shield 104 may extend past the flexible member 110 and define the ends 106, 108, e.g., as shown in
In at least one embodiment, a shell may be placed around the flexible member 110 and/or the shield 104. The shell may have an outer surface that is planar or outwardly-curved (e.g., convex), and the inner surface of the shell may include a plurality of projections, curved ridges, a fish scale pattern, or the like. The shell may be structurally reinforced with a strut, a brace, a rib, or the like that extends between two opposite sides of the shell. The shell may be formed from a composite material (e.g., a fiber-reinforced resin material), which may be surface-treated before molding of the shell. The shell may have at least one inlet configured to receive a liquid material such as a bonding agent. The bonding agent may be used to couple the shell to the outer surface of the tubular and the flexible members. The flexible member may provide support to the shell. Additional details of the shell may be found in PCT Application No. PCT/EP2013/057416, filed Apr. 9, 2013, which is hereby incorporated by reference in its entirety.
Referring to
Although described above with reference to a relatively thin (in axial dimension and relative to the total axial width of the stop collar 100) flexible member 110, it will be appreciated that the flexible member 110 may have a larger axial width, up to a width that equals the axial dimension, from end 106 to end 108, of the stop collar 100. For example, rather than helically wrapping the flexible member 110 around the tubular 102, each turn of the tubular 102 with respect to the flexible member 110 (either the tubular 102 or the flexible member 110 may be moving, as described above) may result in a complete layer of the flexible member 110 being deposited. Thus, as will be described below, multiple layers of the flexible member 110 may be wrapped around the tubular 102, e.g., in concentric layers.
Further, in some embodiments, the first and second layers 401, 402 may have differently-shaped cross-sections. For example, the first layer 401 may have a circular cross-section, while the second layer 402 may have a braided cross-section. Any other combination of cross-sections may be provided for the first and second layers 401, 402, whether the same or different.
In another embodiment, the flexible member 110 may provide both of the first and second layers 401, 402. For example, in an embodiment in which the flexible member 110 is a relatively thin (relative to the axial length of the stop collar 100), helically-wrapped member, the first layer 401 may be constructed by wrapping the flexible member 110 around the tubular 102, and then the wrapping direction may be reversed, with the second layer 402 of the flexible member 110 being wrapped around the first layer 401 thereof. In another embodiment, the flexible member 110 may have the same width as the stop collar, and thus each turn of the tubular 102 may provide an additional layer.
Moreover, as depicted in
Still referring to
Further, ends 1002, 1004 of the mandrel 900 may extend from the sheath 902. In a pre-coiled embodiment, the coil of flexible member 110 may initially have an inner diameter that is larger than the outer diameter of the tubular (e.g., tubular 102), and may thus slide onto the tubular. Upon reaching an installation point, which may or may not include a layer of adhesive, such as the layer 208, a tension force may be applied to the ends 1002, 1004, thereby reducing the diameter of the mandrel 900. In some cases, at least initially, the sheath 902 may move with the mandrel 900, but may become engaged between the mandrel 900 and the tubular. Continued application of force on the ends 1002, 1004 may cause the mandrel 900 to move relative to the sheath 902, and the sheath 902 may be compressed between the tubular and the mandrel 900. In some embodiments, the sheath 902 may be made from a relatively soft material, such as a plastic, elastomer, or relatively soft metal, which may prevent the mandrel 900, which may be made of a harder material, from damaging the tubular during constriction of the mandrel 900.
In other embodiments, the flexible member 110 including the mandrel 900 and the sheath 902 may be wound as it is installed onto the tubular 102, for example, similar to the way in which the flexible member 110 is installed as shown in and described above with reference to
Prior to installing the flexible member 1100 onto the tubular, a torque force may be applied to the flexible member 1100, e.g., to the ends 1102, 1104 thereof. The torque force may serve to expand the flexible member 1100 at least to a second diameter D2, e.g., by reducing the number of turns 112. Such torque may also create spaces between the turns 112, which may cause the length of the flexible member 1100 to increase to a second length L2. The flexible member 1100 in the expanded configuration may be received over a tubular having a diameter that is between the first and second diameters D1, D2 of the flexible member 1100. Upon reaching a desired installation location, the torque force may be removed, causing the flexible member 1100 to contract. In another embodiment, a temporary adhesive may be employed to retain the flexible member 1100 in the expanded configuration for a duration, before breaking down and allowing the flexible member 1100 to contract. Full contraction to the first, natural diameter D1 may be prevented by the flexible member 1100 bearing on the tubular, and thus the flexible member 1100 may apply a spring force on the tubular, which may provide the gripping/holding force.
Further, the heads 1204 may extend radially outwards from the tubular 102, farther than the elongate bodies 1206. The heads 1204 may thus collectively define end rings on either side of the insert 1200, which may be engaged by a tool or another device disposed around the tubular 102, e.g., in the wellbore. For example, the combination of the elongate bodies 1206 and the flexible member 120 may extend to approximately the same radial position as the radial-outside of the heads 1204; however, in other embodiments, the heads 1204 may extend farther outwards than, or not as far outwards as, the flexible member 110 disposed on the elongate bodies 1206.
The segments 1202 may be connected together, e.g., using an elastic band received around the tubular 102. In another embodiment, the segments 1202 may be unitary, glued, snapped, hooked, or otherwise held together circumferentially, so as to facilitate installation around the tubular 102.
In operation, the insert 1200 may, as shown, be sandwiched between the flexible member 110 and the tubular 102. The insert 1200 may be fabricated at least partially from a material that is relatively soft compared to the tubular 102 and the flexible member 110. For example, the insert 1200 may be made from a molded plastic, an elastomer, another plastic, a composite, a relatively soft metal, etc. Thus, the insert 1200 may be compressed when the flexible member 110 is received around the tubular 102, and may provide a buffer between the flexible member 110 and the tubular 102, e.g., to reduce the risk of damaging the tubular 102, to increase holding forces (e.g., by providing a high-friction insert 1200 and/or by including teeth or other marking structures on an inner surface and/or outer surface of the insert 1200), and/or the like.
In at least one embodiment, the insert 1200 may contain an adhesive, which may be released upon compression of the insert 1200 by the flexible member 110. For example, the insert 1200 may include encapsulated pockets of adhesive therein, and may include holes or predetermined rupture locations. When the flexible member 110 provides a radially-inward gripping force, the adhesive may migrate out of the pockets and into contact with the flexible member 110, forming a bond between the flexible member 110 and the tubular 102 and/or the insert 1200.
Accordingly, the engaging ring 1300 may provide a generally uniform, radially-extending surface against which tools, etc., may engage and push toward the flexible member 110. The engaging ring 1300 may thus be sandwiched between the flexible member 110 and the force-applying member (e.g., tool, component, etc.). As such, the flexible member 110 may continue providing the holding force, while the engaging ring 1300 may prevent the force-applying member from damage caused by engaging the end 114-1 of the helical, flexible member 110.
It will be appreciated that a second engaging ring may be provided, e.g., adjacent to the opposite axial side 1304 of the flexible member 110, e.g., to provide for engagement with a force-applying member in an opposite direction.
The profiled inner surfaces 1404, 1406 may thus define a shoulder 1408, 1410 at the starting points thereof. The shoulders 1408, 1410 may be configured to receive the ends 114-1, 114-2, respectively, of the flexible member 110, and the profiled inner surfaces 1404, 1406 may be configured to engage a maximum surface area of the flexible member 110 along the proximal turn 112.
As shown, the end collars 1502, 1504 may be disposed on opposite axial sides of the stop collar 100, i.e., in a “straddled” configuration. In this embodiment, the ribs 1506 extend over the stop collar 100. In addition, engaging members may be coupled with one or both of the end collars 1502, 1504 and the stop collar 100. In other embodiments, one or more stop collars 100 may be disposed on the outboard axial ends of the end collars 1502, 1504.
The end collars 1502, 1504 may bear on the stop collar 100, e.g., when passing through a wellbore restriction or otherwise experiencing axially-directed (e.g., drag) forces. The stop collar 100 may provide a holding force, which may retain the axial position of the centralizer 1500 with respect to the tubular 102.
The method 1600 may include positioning installation rings on a tubular, as at 1602. Positioning the installation rings may occur by sliding the installation rings over an end of the tubular, or by opening or decoupling segments of the installation rings, so as to position the installation rings around the tubular. It will be appreciated that at least block 1602 (and at least blocks similarly indicated by dashed lines) are optional and may be omitted from embodiments of the method 1600.
The method 1600 may proceed to applying a layer of adhesive to the tubular, for example, between the installation rings (where provided), as at 1604. Further, in an embodiment, an insert, such as a spline, may be disposed on the tubular, as at 1606. At this point, a flexible member may be prepared for disposing around the tubular. In an embodiment, the flexible member may be radially expanded, for example, in embodiments in which the flexible member includes a helical spring, as at 1607.
The flexible member may be wrapped more than once around the tubular, as at 1608. For example, the flexible member may be helically wrapped around the tubular such that the flexible member defines a plurality of axially-adjacent turns, as at 1610. In such helical wrapping, an end of the flexible member may be fixed in position relative to the tubular, as at 1611, for example, the end of the flexible member (or a portion thereof proximal to the end) may be fixed to another portion of the flexible member. In an embodiment, the flexible member may be heated, such that it shrinks, during or after the winding process. In an embodiment, the flexible member may be concentrically wrapped around the tubular, as at 1612. Such helical and concentric embodiments may provide one or more radially adjacent layers of the flexible member.
The method 1600 may also include applying a tension to the flexible member such that the flexible member applies a radially-inward gripping force on the tubular, as at 1618. For example, the method 1600 may include applying the tension to the flexible member while wrapping the flexible member around the tubular, as at 1620. In another example, the method 1600 may include applying a tension to ends of a mandrel of the flexible member disposed within a sheath of the flexible member, such that the mandrel moves relative to the sheath, as at 1622. In another example, the method 1600 may include radially contracting the flexible member, as at 1623. The method 1600 may then proceed to applying a shield (e.g., a coating) to the flexible member, as at 1624, and removing the installation rings, as at 1626.
The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
This application claims priority to U.S. Provisional patent application having Ser. No. 61/867,023, which was filed on Aug. 17, 2013. The entirety of this provisional application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61867023 | Aug 2013 | US |
