Segmented bend-limiter for slickline rope sockets and cable-heads

A chain of bend-limiter segments is coupled together. The chain has a first end and a second end. The chain is bendable such that an angle between the first end and the second end is at least N degrees and a radius of curvature of the chain is at least M. A cable is inserted through the chain from the first end to the second end. The chain and the cable are coupled to a tool. The tool is pulled using the cable. The chain maintains a radius of curvature of the cable greater than M and prevents a stress level in the cable from exceeding a yield point.

BACKGROUND

In the oil field, slickline cable is used to introduce a slickline tool into a borehole that may be used for the production of hydrocarbons. The borehole may deviate, such that the borehole may transition, for example, from a vertical region to a horizontal region. Moving the slickline tool from a horizontal orientation to a vertical orientation, for example, without harming (e.g., kinking or breaking) the slickline cable is a challenge.

DETAILED DESCRIPTION

The following detailed description illustrates embodiments of the present disclosure. These embodiments are described in sufficient detail to enable a person of ordinary skill in the art to practice these embodiments without undue experimentation. It should be understood, however, that the embodiments and examples described herein are given by way of illustration only, and not by way of limitation. Various substitutions, modifications, additions, and rearrangements may be made that remain potential applications of the disclosed techniques. Therefore, the description that follows is not to be taken as limiting on the scope of the appended claims. In particular, an element associated with a particular embodiment should not be limited to association with that particular embodiment but should be assumed to be capable of association with any embodiment discussed herein.

While the following disclosure is described in the context of a slickline cable being used in a hydrocarbon well environment, it will be understood that the equipment and techniques described herein are useful in any environment in which it is desired to limit the bend radius of a flexible cable, rope, E-line, fiber optic cable, power cable or similar material. Further, the equipment and techniques described herein may be useful in sea-based production systems, land-based systems, multilateral wells, all types of drilling systems, all types of rigs, measurement while drilling (“MWD”)/logging while drilling (“LWD”) environments, wired drillpipe environments, coiled tubing (wired and unwired) environments, wireline environments, and similar environments.

FIG. 1is an elevation of a slickline system100with a chain of bend-limiter segments105coupled to a tool110deployed into a borehole115. The slickline system100is used to convey the tool110(or tools) into the borehole115, and to retrieve the tool110therefrom, using a slickline cable120. The slickline cable120, may be thin, hard, and rigid, such as the composite slickline described in WO 2014/137335 (entitled “Bonded Slickline and Methods of Use”), which is assigned to the assignee of the present application, however the slickline system100may instead use a wire slickline cable120with different material properties and varied physical dimensions. The slickline cable120may provide a forward path for signals from the tool110to a surface equipment module125located on the surface of the earth, or vice versa, as described in U.S. Pat. No. 8,547,246 (entitled “Telemetry System for slickline enabling real time logging”), which is assigned to the assignee of the present application. The slickline cable120is stored on a draw works or spool130and proceeds through a pulley or system of pulleys135and through a packing assembly (not shown).

The slickline cable120may be electronically and mechanically coupled to the tool110. The coupling between the slickline cable120and the tool110may include a sturdy mechanical connection, capable of sustaining the connection through the entire slickline operation. In one or more embodiments, there is an electronic or optical connection (not shown) between the slickline cable120and the tool110. The tool110may include sensors and actuators, such as probes, pressure sensors, and acoustic sensors.

The chain of bend-limiter segments105may include a plurality of bend-limiter segments140. The chain of bend-limiter segments105may include a first end145and a second end150. The borehole115may bend at a first location155causing the chain of bend-limiter segments105to bend at the first location155. InFIG. 1, the bend is shown to be N degrees, where N can be any practical number between 0 and 360. The bend in the borehole115causes the slickline cable120to bend and undergo stress as the tool traverses the first location155through the bend, or vice versa. That is, the slickline cable120bends as the tool110is inserted into the borehole115and as it is withdrawn from the borehole115. Similarly, the slickline cable120may experience similar stresses when the tool110is picked up using the slickline cable120from a deck on an offshore platform or from the ground at a land-based drilling system. The chain of bend-limiter segments105may assist the slickline cable120transition through restrictions, such as tubing re-entry guides (not shown.)

Typically, the slickline cable120has a minimum radius of curvature specification M, where M is measured in any units of length (English units, scientific units, etc.) below which the slickline cable120is susceptible to damage, such as kinking, breaking, or, more generally, experiencing stress that causes the slickline cable120to exceed its yield point (i.e., the point at which stress will cause the slickline cable to deform plastically rather than elastically) and permanently deform due to overstressing caused by subjecting the slickline cable120to a too-tight radius of curvature. Further, the slickline cable120is constrained where it joins to the tool110, making the slickline cable120more susceptible to damage in that area.

To reduce the likelihood of such damage, the chain of bend-limiter segments105is coupled to the slickline cable120and to the tool110to restrict the radius of curvature M of the slickline cable120where it joins the tool110. The chain of bend-limiter segments105may include a sucker rod adaptor160, a fishneck end165and shear pins170to facilitate coupling the chain of bend-limiter segments105to the slickline cable120and the tool110.

As illustrated in the magnified view A ofFIG. 1, each bend-limiter segment140may include a male end175having a male shape. The bend-limiter segment140may include a female end180couplable to the male end175and having a cavity185. The cavity185has a cavity shape that is complementary to the male shape with a restriction in the cavity185, discussed in more detail below, which confines angular movement of the male shape within the cavity185to P degrees from a longitudinal axis through the male end175and the female end180. The total bend allowed by the chain of bend-limiter segments105is P multiplied by the number of bend-limiter segments140in the chain of bend-limiter segments140. For example, if P is 10 degrees and there are 9 bend-limiter segments140, the total bend allowed by the chain of bend-limiter segments105is 90 degrees (9×10).

Each bend limiter segment140may include a channel190having a diameter D through the male end175and the female end180along the longitudinal axis. The chain of bend-limiter segments105may form a passage195from the first end145to the second end150. The combined length of the male end175and the bottom of the cavity185is L. The radius of curvature M is defined by P and L:

M=L2⁢Tan(Pz)(1)
For small values of P (i.e, P<2 degrees), M can be approximated as:

M=LSin⁡(P)(2)
For very small values of P (i.e., P<½ degree), M can be approximated as:
L/P   (3)
As can be seen in the equations, M increases as L increases and decreases as P increases.

FIGS. 2A and 2Bare plan views of a bend-limiter segment140. Each bend-limiter segment140may include two halves205couplable along a longitudinal axis200. The two halves205may be identical. The bend-limiter segment140may also include three or more sections (not shown). The bend-limiter segment140may also be a single apparatus not comprising any sections.

FIG. 2Cis a cross-sectional view of the bend-limiter segment140ofFIG. 2AandFIG. 2B. As illustrated inFIG. 2C, the sections205may be coupled together by bolts210or by other methods (i.e., adhesives, welding). The bolts210may couple the sections205along an axial axis215. The longitudinal axis200may be substantially perpendicular to the axial axis215.

The bend-limiter segment140may be manufactured from a polymer. The bend-limiter segment140may be manufactured from a metal or a similar material.

In order to retrieve the tool110from the borehole115using the slickline cable120while maintaining the minimum radius of curvature M of the slickline cable120, the bend-limiter segment140may be designed and manufactured to meet certain parameters. Those parameters may include the diameter D of the passage195; the length L and width of each bend-limiter segment140; and other parameters of the bend-limiter segments140.

An example of a bend-limiter segment140is illustrated inFIG. 3A, which is a cross-sectional view of a bend-limiter segment140. As previously mentioned, the bend-limiter segment140may have a male end175. The male end175may be positioned along the longitudinal axis200. The male end175may have a ball joint. The male end175may have a conical shape. The male end175may have a bowl shape. The male end175may have a parabolic shape. The male end175may have a tapered shape.

The male end175have may have a crown surface310that is substantially parallel to the axial axis215. The crown surface310may have a flat surface. The crown surface310may integrate with a crown rocker315. The crown rocker315may have the shape of a truncated cone with a crown rocker large end320and a crown rocker small end325. The crown rocker small end325may integrate with the crown surface310. The area of the crown rocker large end320is greater than the area of the crown rocker small end325. There may be a sloped surface330between the crown rocker small end325and the crown surface310.

The crown rocker315may be integral with a truncated cone335. The truncated cone335may be substantially positioned along the longitudinal axis200. The outer surface of the truncated cone335may have a conical shape. The outer surface of the curved truncated cone335may have a parabolic shape. The truncated cone335may be truncated at a desired length. The dimensions of the curved truncated cone335may be one of the factors that define the maximum angle P that can be achieved between the longitudinal axis200athrough one of the bend-limiter segments140and the longitudinal axis200bthrough the other bend-limiter segment140.

The curved truncated cone335may have a bottom surface340integral with the crown rocker315and a top surface345integral with a neck350(discussed below). The bottom surface340is opposite the top surface345. The curved truncated cone335may decrease in diameter along the longitudinal axis200starting from the bottom surface340to the top surface345. The short dimension of the curved truncated cone335may be substantially parallel to the longitudinal axis200. The long dimension of the truncated cone335may be substantially parallel to the axial axis215.

The truncated section of the curved truncated cone335may be integral with a neck350. The neck350may be positioned substantially along the longitudinal axis200. The neck350may have substantially the same area as the truncated section of the curved truncated cone335. The neck350may have a substantially cylindrical shape. The neck350may have the shape of a cylinder flared on both ends. The neck350may integrate with a shoulder355.

The shoulder355is substantially positioned along the axial axis215. The shoulder355may have the shape of a truncated cone. The shoulder355integrates with the neck355at one end and with a body360at the other end.

The body360may be cylindrical. The body360may have a cap screw hole365for placing the screw bolts210. The cap screw hole365is bored through the body360. The body360may have a plurality of cap screw holes365. The body360may have a top end370and a bottom end375. The body top end370may be integrated with the shoulder355. The body bottom end375may be integral with the female end180.

The female end180may include a cavity185. The cavity185may be positioned substantially along the longitudinal axis200and opposite the male end175. The cavity185may have a cavity bottom surface380positioned substantially along the axial axis215. The cavity bottom surface380may have substantially the same surface area as the crown rocker large end320.

The cavity185may also include a cavity wall385integrated with the cavity bottom surface380. The cavity wall385may be adjacent the cavity bottom surface380. The cavity wall385may have substantially the same shape as the curved truncated cone335. The cavity185may have a conical shape. The cavity180may have a bowl shape. The cavity180may have a parabolic shape. The cavity180may be tapered.

The cavity180may have a cavity opening390positioned substantially along the axial axis215and opposite the cavity bottom surface380. The cavity opening390may be large enough to allow the male end175to rotate sufficiently in the cavity185to achieve the angle P, as shown inFIG. 3B.

The bend-limiter segment140may include the channel190. The channel190may be positioned substantially along the longitudinal axis200. The channel190may traverse the entire length of the bend-limiter segment140. The channel190may have a diameter at the male end175that gradually reduces as it traverses the body360, and then gradually increases as it exits the female end180.

FIG. 3Bis a cross-sectional view of multiple bend-limiter segments140ofFIG. 2A and 3Bcoupled together. The restriction in the cavity185that restricts movement of bend-limiters140relative to each other is provided by the interaction between the crown rocker surface310, the crown rocker315, the neck345, the cavity bottom surface380, and the cavity wall385.

Another example of the chain of bend-limiter segments105is illustrated inFIGS. 4A-4C.FIG. 4Ais a cross-sectional view of a chain of bend-limiter segments105. The chain of bend-limiter segments105may include an external fishneck165coupled to either end of the chain of bend-limiter segments105. The chain of bend-limiter segments105may include a slickline sucker rod adaptor160coupled to either end of the chain of bend-limiter segments105. The chain of bend-limiter segments105may include a non-metallic hose405(also illustrated in magnified view A ofFIG. 4A). The non-metallic hose405may traverse the entire length of the chain of bend-limiter segments105through the passage created by the channels190.

FIG. 4Bis a plan view of the bend-limiter segment140shown inFIG. 4A. The bend-limiter segment140may include the male end175. The male end175may include a dome410. The male end175may include a base415. The base415may have the shape of a tapered cylinder flared at one end. The base415may include a base top end420, which may be integrated with the dome410. The base415may include a base bottom end425. The base bottom end425may be flared such that it has a surface area larger than the base top end420. The male end175may include the channel190.

FIG. 4Cis a cross-sectional view of the bend-limiter segment ofFIG. 4B. The bend-limiter segment140may include the female end180. The female end180may include the cavity185. The cavity185may have a cavity bottom surface430. The cavity bottom surface430may have a shape substantially the same shape as the dome410. The cavity185may include a cavity wall435. The cavity wall435may be adjacent to the cavity bottom surface430. The cavity wall435may have substantially the same shape as the base415. The cavity185may include a cavity opening440. The cavity opening440may be opposite the cavity bottom surface430. The cavity opening440may be adjacent the cavity wall435. The cavity opening440may have substantially the same surface area as the base bottom end425.

When two or more bend-limiter segments140are coupled together, as illustrated inFIG. 4A, the restriction in the cavity185that restricts movement of bend-limiters140relative to each other is provided by the interaction of the dome410, the base415, the cavity wall435, and the cavity bottom surface430

Another example of the chain of bend-limiter segments105is illustrated inFIGS. 5A-5C.FIG. 5Ais a cross-sectional view of a chain of bend-limiter segments105. The chain of bend-limiter segments105may include the external fishneck165coupled to either end of the chain of bend-limiter segments105. The chain of bend-limiter segments105may include the slickline sucker rod adaptor160coupled to either end of the bend-segments140. The chain of bend-limiter segments105may include the non-metallic hose405(also illustrated in the magnified view A ofFIG. 5A). The non-metallic hose405may traverse the entire length of the chain of bend-limiter segments105through the passage created by the channel190. The chain of bend-limiter segments105may include snap rings500. The snap rings500may be coupled externally to male end175. The snap rings500may be coupled internally to the cavity185.

FIG. 5Bis a plan view of a bend-limiter segment. The bend-limiter segment140may include the male end175. The male end175may include a convex surface505.

The male end175may include a first truncated cone510. A large end of the first truncated cone510may be integral to the convex surface505. The male end175may include a truncated sphere (not shown). The male end165may include a second truncate cone515. The small end of the first truncated cone510may be integral with a small end of the second truncated cone515.

The male end175may include a neck520. The large end of the second truncated cone515may be integral to the neck520. The neck520may be cylindrical.

The male end175may include a male end link525. The male end link525may be cylindrical. The male end link525may include a link top end530. The link top end530may be integrated with the neck520. The male end link525may include a link bottom end535opposite the link top end530. The link top end530may have a surface area larger than the neck520. The link top end530may have a surface area larger than the link bottom end535.

FIG. 5Cis a cross-sectional view of the bend-limiter segment ofFIG. 5B. The bend-limiter segment140may include the female end180. The female end180may include the cavity185. The cavity185may include a cavity bottom surface540. The cavity bottom surface540may have substantially the same shape as the convex surface505. The cavity bottom surface540may have a concave surface.

The cavity185may include a cavity wall545. The cavity wall545may be adjacent the cavity bottom surface540. The cavity wall545may be substantially perpendicular to the cavity bottom surface540. The cavity wall545may have substantially the same shape as the male end link525.

The cavity185may include a cavity opening550, as illustrated inFIG. 5C. The cavity opening550may have substantially the same surface area as the convex surface505. The cavity375may have an area substantially the same as the male end175.

When two or more bend-limiter segments140are coupled together, as illustrated inFIG. 5A, the restriction in the cavity185that restricts movement of the bend-limiters140relative to each other is provided by the interaction of the convex surface505, the truncated cone neck520, the cavity bottom surface540, and the cavity wall545.

Another example of the chain of bend-limiter segments105is illustrated inFIGS. 6, and 7A-7C.FIG. 6is an exploded plan view of a chain of bend-limiter segments105. The chain of bend-limiter segments105may include the external fishneck165coupled to either end of the chain of bend-limiter segments105. The chain of bend-limiter segments140may include the slickline sucker rod adaptor160coupled to either end of the chain of bend-segments105.

The chain of bend-limiter segments105may include the male end175. The chain of bend-limiter segments105may include the female end180. The chain of bend-limiter segments105may include a collar605(discussed below in connection withFIGS. 7A-7C). The chain of bend-limiter segments105may include shear pins170(discussed below in connection withFIG. 7A).

FIG. 7Ais a cross-sectional view of a chain of bend-limiter segments105. The shear pins170may be coupled to the slickline sucker rod adaptor145. The shear pins170may be positioned along the longitudinal axis200and /or the axial axis215(not shown). In cases where the tool110is stuck in the borehole115, an operator (not shown) may “jar” the slickline cable120, shearing the shear pins170, and retract the chain of bend-limiter segments105from the borehole115.

FIG. 7Bis an exploded cross-sectional view of a bend-limiter segment105. The bend-limiter segment140may include the male end175. The male end175may include a truncated sphere705. The truncated sphere705may be truncated at a desired length on opposite sides of the truncated sphere705. The truncated sphere705may include a truncated top end710. The truncated sphere705may include a truncated bottom end715.

The bend-limiter segment140may include a shaft720. The shaft720may be coupled to the truncated bottom end715. The shaft720may be a cylindrical. The shaft720may have a threaded end725.

The bend-limiter segment140may include the channel190that traverses the entire length of the male end175. The channel190may have a diameter that decreases as it traverses the truncated sphere705and increases as it exits the shaft720. The channel190may include the non-metallic hose405. The non-metallic hose405may traverse the entire length of the bend-limiter segment140and/or the chain of bend-limiter segments105.

The bend-limiter segment140may include the collar605. The collar605may have a top collar cavity735that has substantially the same shape as the truncated sphere705. The collar730may include a bottom collar cavity740. The bottom collar cavity740has a diameter that is larger than the shaft720to allow the male end to swivel within the bottom collar cavity740and the top collar cavity735. The collar605may include spanner holes745. The spanner holes may allow a spanner wrench to remove the collar730from the female end180.

The collar605may include a collar neck750. The collar neck750may include an irregular exterior. The collar neck750may be threaded. The collar605may include a collar shoulder755. The collar shoulder755may be coupled to the collar neck750. The collar shoulder755may be integral with the collar neck750. The collar shoulder755may have an outside diameter that is greater than the collar neck's750outside diameter.

The bend-limiter segment140may include the female end180. The female end180may include a clasp end760. The clasp end may be threaded. The female end180may include a receptacle end765opposite the clasp end760. The receptacle end765may be threaded. The receptacle end765has an internal shape that is complimentary to the external shape of the collar605.

FIG. 7Cis a cross-sectional view of a bend-limiter segment140. When two or more bend-limiter segments140are coupled together, as illustrated inFIG. 7C, the restriction in the cavity185that restricts movement of bend-limiters140relative to each other is provided by the interaction of the truncated sphere705, the shaft720, the collar605, the female end180.

FIG. 8is a flow chart. A technique for limiting the bend in a cable includes coupling together a chain of bend-limiter segments (such as chain of bend-limiter segments105). The chain has a first end (such as first end145) and a second end (such as second end150). The chain is bendable such that an angle between the first end (such as first end145) and the second end (such as second end150) is at least N degrees and a radius of curvature of the chain is at least M (block805). A cable (such as cable120) may be inserted through the chain (such as chain of bend-limiter segments105) from the first end (such as first end140) to the second end (such as second end150) (block810). A chain (such as chain of bend-limiter segments105) and a cable (such as cable120) may be coupled to a tool (such as tool110) (block815). The tool (such as tool110) may be pulled using the cable (such as cable120), the chain maintaining a radius of curvature of the cable (such as cable120) greater than M and preventing a stress level in the cable (such as cable120) from exceeding a yield point (block820).

In one aspect, a method features coupling together a chain of bend-limiter segments, the chain having a first end and a second end, the chain being bendable such that an angle between the first end and the second end is at least N degrees and a radius of curvature of the chain is at least M. A cable is inserted through the chain from the first end to the second end. The chain and the cable are coupled to a tool. The tool is pulled using the cable. The chain maintains a radius of curvature of the cable greater than M and prevents a stress level in the cable from exceeding a yield point.

Implementations may include one or more of the following. The cable may be coupled to a surface equipment. The chain of bend-limiter segments, the tool, and the cable may be deployed into a borehole, past a first location where the borehole deviates. Pulling the tool using the cable may include retrieving the tool from the deviated borehole when the tool passes through the first location. Pulling the tool using the cable may include lifting the tool from a first orientation to a second orientation different from the first orientation using the cable. Coupling together a chain of bend-limiter segments may include coupling two or more bend-limiter segments. Coupling together a chain of bend-limiter segments may include dividing the bend limiter segments into two or more halves. Coupling together a chain of bend-limiter segments may include mounting the two or more halves about the cable. Coupling together a chain of bend-limiter segments may include securing the two or more halves to the cable.

In one aspect, an apparatus features a chain of bend-limiter segments, the chain of bend-limiter segments having a first end and a second end. The chain of bend-limiter segments is bendable such that an angle between a first end and a second end is at least N degrees. A radius of curvature of the chain of bend-limiter segments is M when the angle between the first end and the second end is N degrees. N and M are determined by parameters of the bend-limiter segments. The bend-limiter segments have channels such that the chain of bend-limiter segments has a passage from the first end to the second end.

Implementations may include one or more of the following. The bend-limiter segments may include a male end having a male shape. A female end may be coupled to the male end. The female end may have a cavity with a cavity shape that is complementary to the male shape with a restriction in the cavity that confines angular movement of the male shape within the cavity to P degrees from a longitudinal axis through the male end and the female end. The bend-limiter segments may include a channel having a diameter D through the male end and the female end along the longitudinal axis.

In one aspect, a system features a surface equipment located on a surface of the earth. The system includes a tool coupled to the cable. The system includes a bend-limiter coupled to the cable adjacent the tool. The bend-limiter includes a chain of bend-limiter segments, the chain of bend-limiter segments having a first end and a second end. The chain of bend-limiter segments is bendable such that an angle between the first end and the second end is at least N degrees. A radius of curvature of the chain of bend-limiter segments is M when the angle between the first end and the second end is N degrees. N and M are determined by parameters of the bend-limiter segments. The bend-limiter segments have channels such that the chain of bend-limiter segments has a passage from the first end to the second end.

Implementations may include one or more of the following. The chain of bend-limiter segments may include a first end and a second end. The chain of bend-limiter segments may be bendable such that an angle between a first end and a second end is at least N degrees. A radius of curvature of the chain of bend-limiter segments may be M when the angle between the first end and the second end is N degrees. N and M may be determined by parameters of the bend-limiter segments. The bend-limiter segments may include a male end having a male shape. The bend-limiter segment may include a female end coupled to the male end and having a cavity with a cavity shape that is complementary to the male shape with a restriction in the cavity that confines angular movement of the male shape within the cavity to P degrees from a longitudinal axis through the male end and the female end. The bend-limiter segment may include a channel having a diameter D through the male end and the female end along the longitudinal axis.

The operations of the flow diagrams are described with references to the systems/apparatus shown in the block diagrams. However, it should be understood that the operations of the flow diagrams could be performed by embodiments of systems and apparatus other than those discussed with reference to the block diagrams, and embodiments discussed with reference to the systems/apparatus could perform operations different than those discussed with reference to the flow diagrams.

The word “coupled” herein means a direct connection or an indirect connection.

The text above describes one or more specific embodiments of a broader invention. The invention also is carried out in a variety of alternate embodiments and thus is not limited to those described here. The foregoing description of an embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.