MANAGING STRAIN ON A DOWNHOLE CABLE

Abstract

Techniques for managing strain on a downhole cable, such as a slickline or wireline, include a wire coupled with a communication line, such as a fiber optic cable or metallic (or non-metallic) conductor. In one example, a downhole cable includes a wire to support a downhole tool string; and a communication line non-linearly coupled with the wire, the communication line sized to communicate instructions, that include at least one of logic or data to the downhole tool, and elongate based on an axial force that acts on the downhole cable.

Description

TECHNICAL BACKGROUND

This disclosure relates to managing strain on a downhole cable.

BACKGROUND

A downhole cable is often used to convey a downhole tool into a wellbore. For example, a downhole cable can be a strong wire (e.g., wireline, slickline, and/or other downhole cable) for withstanding the dynamic and static weight of the downhole tool. The weight includes the dynamic and static tension forces in the downhole cable when the downhole tool accelerates or decelerates. The wire can also communicate telemetric signals with the downhole tool. The dynamic weight of the downhole tool can slightly stretch the downhole cable. Other factors can also change the strain in the downhole cable.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional side view of a well system with an example downhole cable;

FIGS. 2A-2B illustrate cross-sectional views of example embodiments of a downhole cable that manages strain on components of the cable;

FIGS. 3A-3B illustrate cross-sectional views of example embodiments of a downhole cable that manages strain on components of the cable; and

FIG. 4 illustrates an example method performed with a downhole cable.

DETAILED DESCRIPTION

The present disclosure relates to managing strain on a downhole cable, such as a slickline or wireline, that includes a wire coupled with a communication line, such as a fiber optic cable or metallic (or non-metallic) conductor. In a general implementation, a downhole cable includes a wire to support a downhole tool string; and a communication line non-linearly coupled with the wire, the communication line sized to communicate instructions, that include at least one of logic or data to the downhole tool, and to elongate based on an axial force that acts on the downhole cable.

In a first aspect combinable with the general implementation, the communication line includes at least one of a fiber optic line or a metallic conductor.

In a second aspect combinable with any of the previous aspects, the wire includes a composite material.

In a third aspect combinable with any of the previous aspects, the communication line is non-linearly embedded in a matrix of the composite material.

In a fourth aspect combinable with any of the previous aspects, the communication line is non-linearly embedded in the matrix of the composite material in a helical or zig-zag path.

In a fifth aspect combinable with any of the previous aspects, the wire includes a flexible rod, and the communication line is non-linearly wrapped around the flexible rod.

A sixth aspect combinable with any of the previous aspects further includes a coating that at least partially covers the communication line and the flexible rod.

In a seventh aspect combinable with any of the previous aspects, the coating includes polyether ether ketone.

In an eighth aspect combinable with any of the previous aspects, for a particular portion of the downhole cable, a length of the communication line that extends between ends of the particular portion is greater than a length of the wire that extends between the ends of the particular portion.

In a ninth aspect combinable with any of the previous aspects, a value that defines an allowable strain of the wire is greater than a value that defines an allowable strain of the communication line.

In a tenth aspect combinable with any of the previous aspects, a diameter of the downhole cable is about 0.138 inches.

In an eleventh aspect combinable with any of the previous aspects, the composite material includes polyphenylene sulfide.

In a twelfth aspect combinable with any of the previous aspects, the downhole cable includes a slickline, and the wire includes a single solid wire.

In a thirteenth aspect combinable with any of the previous aspects, the downhole cable includes a wireline, and the wire includes a braided wire.

Another general implementation includes a method of managing strain on a downhole cable that includes running a downhole tool coupled to a downhole cable into a wellbore, the downhole cable including a wire and a communication line non-linearly coupled with the wire; operating the downhole tool in the wellbore by transmitting, on the communication line, instructions that include at least one of logic or data between the downhole tool and a terranean surface; receiving a force in an axial direction on the downhole cable; and in response to the received force, elongating the communication line from a substantially non-linear position toward a substantially linear position.

In a first aspect combinable with the general implementation, the communication line includes at least one of a fiber optic line or a metallic conductor.

In a second aspect combinable with any of the previous aspects, the communication line is non-linearly embedded in a matrix of a composite material.

In a third aspect combinable with any of the previous aspects, elongating the communication line from a non-linear position toward a linear position includes elongating the communication line from a helical or zig-zag position toward the substantially linear position.

A fourth aspect combinable with any of the previous aspects further includes receiving a second force in the axial direction on the downhole cable that is less than the received force; and in response to the second force, shortening the communication line toward the substantially non-linear position.

In a fifth aspect combinable with any of the previous aspects, the wire includes a flexible rod, and the communication line is non-linearly wrapped around the flexible rod.

In a sixth aspect combinable with any of the previous aspects, the downhole cable further includes a coating that at least partially covers the communication line and the flexible rod.

In a seventh aspect combinable with any of the previous aspects, for a particular portion of the downhole cable, a length of the communication line that extends between ends of the particular portion is greater than a length of the wire that extends between the ends of the particular portion.

In an eighth aspect combinable with any of the previous aspects, the logic or data includes values associated with telemetry data.

Another general implementation includes a downhole conductor that includes a wire that extends a first length between a first end of the downhole conductor and a second end of the downhole conductor, the wire sized to support a downhole tool string in a wellbore; and a data conductor to transmit at least one of logic or data with the downhole tool string and coupled with the wire, the data conductor extending a second length between the first end of the downhole conductor and the second end of the downhole conductor, the second length greater than the first length.

In a first aspect combinable with the general implementation, the data conductor is embedded in a helical path through a composite material of the wire.

In a second aspect combinable with any of the previous aspects, the composite material includes a single homogenous tension member, and the data conductor is wound in a helical path around the member.

A third aspect combinable with any of the previous aspects further includes a protective coating wrapped around the data conductor and the tension member.

In a fourth aspect combinable with any of the previous aspects, the data conductor includes an optical fiber.

In a fifth aspect combinable with any of the previous aspects, each of the wire and the data conductor include respective distal ends that are coterminous with the first end of the downhole conductor and respective proximal ends that are coterminous with the second end of the downhole conductor.

In a sixth aspect combinable with any of the previous aspects, the downhole conductor includes a slickline, and the wire includes a single homogeneous wire, and the data conductor includes a fiber optic conductor.

Various implementations of a downhole cable (e.g., downhole carrier, downhole conveyance, or downhole cable) in accordance with the present disclosure may include one, some, or all of the following features. For example, the communication line may be non-linearly embedded in a downhole cable in a spiral, helical, zig-zag, or sinusoidal path. The communication line can include a fiber optic line and conductor lines, and the communication line can be enclosed in a single line or be twisted using multiple lines. In some implementations, the communication line may be non-linearly wrapped around the composite material including a flexible rod. The non-linear integration of the communication line, either embedded internally or wrapped externally, can relieve excessive strain from the communication line when the composite material extends due to static and dynamic tensile loads, as well as torsional loads and/or temperature variations. Further, in some implementations, a downhole cable according to the present disclosure may decrease linear and torsional strain in the static and dynamic loading of the cable.

FIG. 1 is a schematic cross-sectional side view of a well system 100 with an example downhole cable 110. The well system 100 is provided for convenience of reference only, and it should be appreciated that the concepts herein are applicable to a number of different configurations of well systems. The well system 100 includes a wellbore 108 that extends from a terranean surface 105 through one or more subterranean zones of interest 101. In FIG. 1, the wellbore 108 initially extends vertically and transitions horizontally. In other instances, the wellbore 108 can be of another position, for example, deviates to horizontal in the subterranean zone 101, entirely substantially vertical or slanted, it can deviate in another manner than horizontal, it can be a multi-lateral, and/or it can be of another position.

At least a portion of the illustrated wellbore 108 may be lined with a casing 106, constructed of one or more lengths of tubing, that extends from the terranean surface 105, downhole, toward the bottom of the wellbore 108. The casing 106 provides radial support to the wellbore 108 and seals against unwanted communication of fluids between the wellbore 108 and surrounding formations. Here, the casing 106 ceases at or near the subterranean zone 101 and the remainder of the wellbore 108 is an open hole, e.g., uncased. In other instances, the casing 106 can extend to the bottom of the wellbore 108 or can be provided in another position and in multiple circumferences or thicknesses (e.g., conductor casing or otherwise).

As illustrated, a downhole tool string 120 is coupled to (e.g., supported by) the downhole cable 110, which can be, for example, a wireline, a slickline, an electric line. In the illustrated embodiment, the downhole cable 110 can support a downhole tool string (e.g., one or more downhole tools). In this example, the downhole cable 110 includes a braided (e.g., multiple bound, or intertwined, wires such as wireline or electric line) or solid wire (e.g., a single wire such as slickline) and a communication line. The communication line is coupled with the braided or solid wire such as, for example, embedded in, intertwined with one or more wires, or wrapped around or within one or more wires, in a non-linear (e.g., undulating, helical, zig-zag, or otherwise) configuration.

In the illustrated example, the communication line may have a different Young's modulus than a Young's modulus of the braided or solid wire. In such cases, a maximum strain that the communication line may tolerate (e.g., before failure) may be different than a maximum strain that the braided or solid wire can tolerate (e.g., before failure). In some aspects, for instance, the braided or solid wire may tolerate a higher (e.g., substantially) maximum strain before failure as compared to the communication line.

In some aspects, a particular length (e.g., between two terminating ends) of the downhole cable 110 includes a length of the braided or solid wire and a length of the communication line. In the particular length of the downhole cable 110, the respective lengths of the braided or solid wire and the communication line may also terminate at or close to the terminating ends of the downhole cable 110. In some aspects, the length of the communication line may be greater than (e.g., slightly or substantially) the length of the braided or solid wire because of, for example, the non-linear configuration in which the communication line is coupled with the braided or solid wire.

In one example embodiment (as described more fully with respect to FIGS. 2A-2B and 3A-3B), the downhole cable 110 is a slickline that includes a solid wire and a communication line. The slickline supports tool string 120 and can communicate instructions, data, and/or logic between the tool string 120 and the terranean surface 105 though the communication line (e.g., optical fiber, metallic conductor, or non-metallic conductor). The communication line of the slickline is non-linearly coupled with the solid wire such that strain that exceeds a maximum allowable strain of the communication line, but not a maximum allowable strain of the solid wire, does not cause failure of the communication line or the slickline.

In some implementations, the downhole tool string 120 may communicate with computing systems or other equipment at the surface 105 using the communication capabilities of the downhole cable 110. For example, the downhole tool string 120 may send and receive electrical signals and/or optical signals (e.g., data and/or logic) through respective conductor wire and/or fiber optics of the communication line within the downhole cable 110. In addition, the downhole tool string 120 may be lowered or raised relative to the wellbore 108 by respectively extending or retrieving the downhole cable 110.

During operation, variable tension loading is applied to the downhole cable 110 when the downhole cable 110 lowers or raises the downhole tool string 120. The tension loading is related to the mass, acceleration, and deceleration of the downhole tool string 120. The tension loading can extend the downhole cable 110 axially. The amount of extension is related to the magnitude of the tension loading, the stiffness (e.g., Young's modulus) of the downhole cable 110, and parameters (e.g., diameter) of the downhole cable 110. Because the downhole cable 110 is placed downhole where temperature varies, the downhole cable 110 may also experience thermal expansion or contraction. The thermal expansion or contraction can also contribute to the amount of extension of the downhole cable 110.

When the downhole cable 110 includes two or more different materials, the extension due to tensile loading and thermal effect can be different in the two or more materials. For example, the braided or solid wire of the downhole cable 110 can comprise a composite material, while the communication line can comprise a conductive or fiber optic material (or other data conductor). The braided or solid wire of the cable 110 and the communication line may have different extension limits (e.g., maximum allowable strains without structural damage) and different changes in length when experiencing the same temperature changes (e.g., different coefficient of thermal expansion). Strain values can employ different definitions, for example, engineering strain is the ratio between the total deformation to the original length, e.g., the amount of deformation of unit length.

The different extension limits can impose limitations to the downhole cable 110 if the braided or solid wire and the communication line were integrated linearly (e.g., combined in a one-to-one length ratio). For example, as described, the braided or solid wire can have a higher allowable strain level than the communication line (e.g., made of optical fibers). This can result in a lower tension load rating for the braided or solid wire to prevent failure of the communication line. In some aspects of the present disclosure, failure such as that described above may be presented through the non-linear coupling method to combine the braided or solid wire with the communication line. In some implementations, the diameter of the downhole cable 110 is about 0.138 inches.

FIGS. 2A-2B illustrate an example embodiment of a downhole cable 200 that manages strain on components of the cable 200. In some aspects, the cable 200 can be used as or in place of the cable 110 described in FIG. 1. FIG. 2A is a cross sectional side view of a portion of the downhole cable 110. FIG. 2B is a cross sectional top view of the downhole cable 200. Generally, as with the downhole cable 110, the downhole cable 200 can support a downhole tool string (e.g., one or more downhole tools). The downhole cable 200 includes a braided wire (e.g., multiple bound, or intertwined, wires such as wireline or electric line) or solid wire (e.g., a single wire such as slickline) and a communication line. The communication line is coupled with the braided or solid wire such as, for example, embedded in, intertwined with one or more wires, or wrapped around or within one or more wires, in a non-linear (e.g., undulating, helical, zig-zag, or otherwise) configuration.

In one example of the downhole cable 200, as shown in FIG. 2A, the downhole cable 200 is a slickline that includes a wire 210. The wire 210 can be formed from a metallic or non-metallic material, such as a composite material (e.g., polyphenylene sulfide or other organic polymer, high-performance thermoplastic, or otherwise). The wire 210 is configured to couple to and support a downhole tool string, such as the downhole tool string 120 of FIG. 1. The downhole cable 200 further includes a communication line 220 that is non-linearly coupled with the wire 210. The communication line 220 can be sized to communicate instructions that include logic and/or data to the downhole tool. The communication line 220 can be configured to elongate based on an axial force acting on the cable 200 that relate, for example, to the mass, acceleration, and/or the deceleration of the downhole tool.

In some implementations, the communication line 220 includes at least one of a fiber optic cable or a metallic conductor wire. For example, when communication and/or telemetry with the downhole tool use optical signals, the communication line 220 includes one or more fiber optic cables. When communication and/or telemetry with the downhole tool use electrical signals, the communication line 220 includes one or more metallic conductor wires.

The communication line 220, in the illustrated example, is non-linearly embedded in a matrix of the composite material of the wire 210. For example, the composite material may include metallic alloys, polymers, composites, and/or other materials. In manufacture, the communication line 220 can be continuously fed into the forming of the wire 210, which may be extruded or rolled or otherwise formed. The communication line 220 can be non-linearly embedded in the matrix of the composite material in a helical (or spiral), zig-zag, sinusoidal, or other non-linear path. A helical path may be defined with a constant pitch and radius. A spiral path may be defined with a variable pitch and/or a variable radius. A zig-zag or sinusoidal path may be planar or three-dimensional. Other non-linear path benefiting manufacture or strain management may also be used. As illustrated in FIG. 2A, the communication line 220 is embedded in the wire 210 in a helical path. In FIG. 2B, the helical path is further depicted with a constant or near constant radius.

FIGS. 3A-3B illustrate example embodiments of a downhole cable 300 that manages strain on components of the conduit. In some aspects, the cable 300 can be used as or in place of the cable 110 described in FIG. 1. FIG. 3A is a side view of a portion of the downhole cable 300. FIG. 3B is a compressed cross sectional top view of the downhole cable 300. Generally, as with the downhole cables 110 and 200, the downhole cable 300 can support a downhole tool string (e.g., one or more downhole tools). The downhole cable 300 includes a braided wire (e.g., multiple bound, or intertwined, wires such as wireline or electric line) or solid wire (e.g., a single wire such as slickline) and a communication line. The communication line is coupled with the braided or solid wire such as, for example, embedded in, intertwined with one or more wires, or wrapped around or within one or more wires, in a non-linear (e.g., undulating, helical, zig-zag, or otherwise) configuration.

Similar to the embodiment disclosed in FIG. 2A, in FIG. 3A, the downhole cable 300 may be coupled with a downhole tool string. The downhole cable 300, in this example implementation, may be a slickline that includes a wire 310, a communication line 320, and a coating 315. The communication line 320 can be respectively similar to the communication line 220 as discussed in FIGS. 2A-2B. In this example, the wire 210 includes (e.g., is made of) a composite material that forms a flexible rod. The communication line 320 can non-linearly wrap around the flexible rod, such as in a helical manner. In FIG. 3B, the coating 315 can at least partially cover the communication line 320 and the flexible rod and can protect the communication line 320 from damage and/or contamination. The coating 315 may be made of various thermoset, thermoplastic, or other polymer materials. In some implementations, the coating 315 includes polyether ether ketone.

In both configuration embodiments illustrated in FIGS. 2A and 3A, for a particular portion of the downhole cables 200 and/or 300, the length of the communication line 220 or 320 that extends between ends (or generally, two points) of the particular portion can be greater than the length of the wire 210 or 310 (respectively) that extends between the ends (or the two points) of the particular portion. For example, the helical configuration of the communication line 220 or 320 can be straightened during extension without incurring substantial tensile strain. The communication line 220 or 320 may respectively be allowed to move relative to the composite materials of the wire 210 or 310 during extension.

FIG. 4 illustrates an example method performed with a downhole cable. At 402, a downhole tool is run into a wellbore from a terranean. The downhole tool is coupled with the conduit. The downhole cable includes a slickline that includes a composite material, and a communication line non-linearly coupled with the composite material. The communication line can be used to communicate control or data information between the downhole tool and computing systems at the terranean surface. For example, the communication line can include at least one of a fiber optic line, or a metallic conductor.

In some implementations, the communication line is non-linearly embedded in a matrix of the composite material, such as in a helical, spiral, zig-zag, sinusoidal, or other similar non-linear manner. In some implementations, the downhole cable can include composite material that includes a flexible rod; and the communication line is non-linearly wrapped around the flexible rod. The downhole cable can further include a coating that partially covers the communication line and the flexible rod.

At 404, data signals are transmitted on the communication line within the downhole cable. For example, the data signals can include logic or data between the downhole tool and the terranean surface. The logic or data can include values associated with telemetry data. In some implementations, the data signals can be optical signals sent from optical sensors of the downhole tool. In some implementations, the data signals can be electrical signals sent from electronic devices and sensors. The data signals can also include control signals sent from the terranean surface. Close loop control may also be implemented using the communication line.

At 406, the downhole tool can be operated corresponding to the data signals. For example, the downhole tool can perform certain functions based on a control instruction sent from the terranean surface. The operation of the downhole tool may increase or decrease the tension applied to the downhole cable.

At 408, a force is received on the downhole cable. The force is related to the tension in the downhole cable. The force may have been received at the very beginning of the operation. Discussing the force in this step does not indicate its occurrence in timing or order. The force can be a dynamic tensile load related to the mass of the downhole tool and its acceleration/deceleration.

At 409, in response to the received force, the communication line is elongated from a substantially non-linear position toward a substantially linear position. For example, the elongation may include extending the communication line from a helical, zig-zag, sinusoidal, or spiral position toward the substantially linear position. The substantially non-linear position can be the original unloaded position of the communication line with respect to the slickline. The substantially linear position can be the fully extended position in line with the slickline. For a particular portion of the downhole cable, a length of the communication line that extends between ends of the particular portion can be greater than a length of the slickline that extends between the ends of the particular portion.

In some implementations, a second force less than the received force is received (e.g., during deceleration). In response to the second force, the communication line is shortened from the substantially linear position toward the substantially non-linear position.

A number of examples have been described. Nevertheless, it will be understood that various modifications may be made. For example, even though the illustrations in FIGS. 2A and 3A use respective helical embedment and helical wrapping configurations with the slickline composite materials, other configurations are possible, such as zig-zag, spiral, sinusoidal, among others. The composite material may include substance(s) other than polyphenylene sulfide or include a different material. In the embodiment of FIG. 3A, the coating 315 may also include substance(s) other than polyether ether ketone, or include a different material. Accordingly, other examples are within the scope of the following claims.

Claims

1. A downhole cable, comprising:

a wire to support a downhole tool string; and

a communication line non-linearly coupled with the wire, the communication line sized to communicate instructions, that comprise at least one of logic or data to the downhole tool, and elongate based on an axial force that acts on the downhole cable.

2. The downhole cable of claim 1, wherein the communication line comprises at least one of a fiber optic line or a metallic conductor.

3. The downhole cable of claim 1, wherein the wire comprises a composite material.

4. The downhole cable of claim 3, wherein the communication line is non-linearly embedded in a matrix of the composite material.

5. The downhole cable of claim 4, wherein the communication line is non-linearly embedded in the matrix of the composite material in a helical or zig-zag path.

6. The downhole cable of claim 1, wherein the wire comprises a flexible rod, and the communication line is non-linearly wrapped around the flexible rod.

7. The downhole cable of claim 6, further comprising a coating that at least partially covers the communication line and the flexible rod.

8. The downhole cable of claim 7, wherein the coating comprises polyether ether ketone.

9. The downhole cable of claim 1, wherein for a particular portion of the downhole cable, a length of the communication line that extends between ends of the particular portion is greater than a length of the wire that extends between the ends of the particular portion.

10. The downhole cable of claim 1, wherein a value that defines an allowable strain of the wire is greater than a value that defines an allowable strain of the communication line.

11. The downhole cable of claim 1, wherein a diameter of the downhole cable is about 0.138 inches.

12. The downhole cable of claim 1, wherein the wire comprises polyphenylene sulfide.

13. The downhole cable of claim 1, wherein the downhole cable comprises a slickline, and the wire is a monofilament wire.

14. The downhole cable of claim 1, wherein the downhole cable comprises a wireline, and the wire comprises a braided wire.

15. A method of managing strain on a downhole cable, comprising:

running a downhole tool coupled to a downhole cable into a wellbore, the downhole cable comprising a wire and a communication line non-linearly coupled with the wire;

operating the downhole tool in the wellbore by transmitting, on the communication line, instructions that comprise at least one of logic or data between the downhole tool and a terranean surface;

receiving a force in an axial direction on the downhole cable; and

in response to the received force, elongating the communication line from a substantially non-linear position toward a substantially linear position.

16. The method of claim 15, wherein the communication line comprises at least one of a fiber optic line or a metallic conductor.

17. The method of claim 15, wherein the communication line is non-linearly embedded in a matrix of a composite material.

18. The method of claim 17, wherein elongating the communication line from a non-linear position toward a linear position comprises elongating the communication line from a helical or zig-zag position toward the substantially linear position.

19. The method of claim 15, further comprising:

receiving a second force in the axial direction on the downhole cable that is less than the received force; and

in response to the second force, shortening the communication line toward the substantially non-linear position.

20. The method of claim 15, wherein the wire comprises a flexible rod, and the communication line is non-linearly wrapped around the flexible rod.

21. The method of claim 20, wherein the downhole cable further comprises a coating that at least partially covers the communication line and the flexible rod.

22. The method of claim 15, wherein for a particular portion of the downhole cable, a length of the communication line that extends between ends of the particular portion is greater than a length of the wire that extends between the ends of the particular portion.

23. The method claim 15, wherein the logic or data comprises values associated with telemetry data.

24. A downhole conductor, comprising:

a wire that extends a first length between a first end of the downhole conductor and a second end of the downhole conductor, the wire sized to support a downhole tool string in a wellbore; and

a data conductor to transmit at least one of logic or data with the downhole tool string and coupled with the wire, the data conductor extending a second length between the first end of the downhole conductor and the second end of the downhole conductor, the second length greater than the first length.

25. The downhole conductor of claim 24, wherein the data conductor is embedded in a helical path through a composite material of the wire.

26. The downhole conductor of claim 25, wherein the composite material comprises a single homogenous tension member, and the data conductor is wound in a helical path around the member.

27. The downhole conductor of claim 26, further comprising a protective coating wrapped around the data conductor and the tension member.

28. The downhole conductor of any one of claims claim 24, wherein the data conductor comprises an optical fiber.

29. The downhole conductor of claim 24, wherein each of the wire and the data conductor comprise respective distal ends that are coterminous with the first end of the downhole conductor and respective proximal ends that are coterminous with the second end of the downhole conductor.

30. The downhole conductor of claim 24, wherein the downhole conductor comprises a slickline, and the wire comprises a single homogeneous wire, and the data conductor comprises a fiber optic conductor.