Cable, particularly for use downhole, and method for the manufacture of such a cable - Patent application

Abstract

The present disclosure relates to a cable (100) comprising a core (102) and a plurality of reinforcing elements (107) disposed around the core (102) to cover the core (102), each reinforcing element (107) comprising at least a reinforcing fiber bundle including at least one fiber and a thermosetting matrix impregnating the fiber bundle, each reinforcing element (107) being individually tubed with a thermoplastic coating (112).

Description

[Technical field]

[0001] This application claims priority to and the benefit of EP Application No. 19306209.8, entitled "Cable for Downhole Use", filed September 26, 2019, the entire disclosure of which is hereby incorporated by reference into this specification.

[0002] The present disclosure relates to cables, particularly for downhole use, and methods for manufacturing such cables. [Background technology]

[0003] To perform operations in the open hole, downhole tools are currently lowered in the open hole using either slickline cables or wireline cables. Slickline cables include a single metal wire, typically made of steel, with good mechanical properties such as a breaking strength of 300 daN to 1,500 daN, preferably 600 to 1,000 daN, and in some embodiments, coated with an insulating coating. As shown in FIG. 1, a wireline cable 1 is a cable including one or more central conductors 2 (here one conductor), on which are arranged multiple layers (e.g., two layers 3, 4) of a metal armor wire 5, typically made of steel, wound helically around the one or more central conductors, such that, typically, each armor wire contacts two adjacent armor wires. Such cable architectures using metal armor wires provide strength during logging operations.

[0004] However, the density of steel is such that wireline cables, and to a lesser extent slickline cables, are heavy and require a lot of energy to deploy the cables and carry the tools. Furthermore, typical wireline cables with metal armored wires on the outer diameter have high friction with the wellbore, including casings, etc., and use large amounts of energy to overcome the friction. Furthermore, it can be difficult to reach deep wells, as there is a risk that the metal reinforced cable will break under its own weight.

[0005] Therefore, it is an objective of oil and gas fields to reduce the weight of cables for more efficient downhole operations, however the weight reduction must not adversely affect the mechanical properties of the cable and tool operation. Summary of the Invention

[0006] The present disclosure relates to a cable including a core and a plurality of reinforcing elements disposed around and covering the core, each reinforcing element including at least a bundle of reinforcing fibers including at least one fiber and a thermosetting matrix impregnating the bundle of fibers, each reinforcing element being individually tubed with a thermoplastic coating.

[0007] The present disclosure also relates to a drilling equipment including a winch having a drum for winding a cable, a downhole tool configured to be lowered in a wellbore, and a cable according to any of the embodiments described above having a first end wound around the drum and a second end having the downhole tool attached.

[0008] The present disclosure also relates to a method of manufacturing a downhole cable, the method including forming a plurality of reinforcing elements, the plurality of reinforcing elements including impregnating a reinforcing fiber bundle including one or more reinforcing fibers with a thermosetting matrix, and extruding a thermoplastic coating around each of the plurality of reinforcing elements to form a tube around each reinforcing element. The method also includes disposing the plurality of tubed reinforcing elements around a core so as to cover the core, and curing the thermosetting matrix of the tubed reinforcing elements once disposed around the core.

[0009] While the cables according to the present disclosure have sufficient mechanical properties due to the properties of the reinforcing fibers, the cables reduce the density and weight of the cable, allowing for reduced power when operating downhole tools and also allowing new, more economical options for well site equipment.

[0010] The various aspects of the disclosure may be better understood by reading the following detailed description and by referring to the following drawings. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective exploded view of a wired cable according to the prior art. [Figure 2A] FIG. 1 is a schematic diagram of a well site equipment according to an embodiment of the present disclosure. [Figure 2B] FIG. 2B is a detailed view of a portion of the well site equipment of FIG. 2A. [Diagram 3] FIG. 2 is a cross-sectional view of a cable according to one embodiment of the present disclosure. [Figure 4] FIG. 4 is a perspective view of the cable of FIG. 3 when wound on a drum. [Diagram 5] FIG. 4 is a schematic diagram of a detail of the cable of FIG. 3. [Figure 6] FIG. 2 is a cross-sectional view of a cable according to another embodiment of the present disclosure. [Figure 7] FIG. 2 is a perspective view of a portion of a cable according to another embodiment of the present disclosure. [Figure 8] FIG. 2 is a cross-sectional view of a cable according to another embodiment of the present disclosure. [Figure 9] FIG. 2 is a cross-sectional view of a cable according to another embodiment of the present disclosure. [Figure 10] FIG. 2 is a cross-sectional view of a cable according to another embodiment of the present disclosure. [Figure 11] FIG. 2 is a perspective view of a portion of a cable according to an embodiment of the present disclosure. [Figure 12] FIG. 12 is a cross-sectional view of a cable including a portion of FIG. 11 according to an embodiment of the present disclosure. [Figure 13] 4 is a flow chart of a method for manufacturing a cable according to an embodiment of the present disclosure. [Figure 14] 14 is a schematic diagram of a cable production line according to the production method of FIG. 13. [Figure 15] 1 is a schematic diagram of a cable according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] One or more specific embodiments of the present disclosure are described below. The described embodiments are examples of the technology disclosed in the present invention. Moreover, in order to provide a concise description of these embodiments, some features of the actual implementations may not be described herein. As with any engineering or design project, it should be recognized that in the development of any such actual implementation, many implementation-specific decisions may be made to achieve the developer's particular goals, such as compliance with system-related and business-related constraints that may vary from implementation to implementation. Moreover, it should be recognized that such development efforts may be complex and time-consuming, but are nevertheless routine undertakings of design, fabrication, and manufacture for those of ordinary skill in the art having the benefit of this disclosure.

[0013] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," and "the" are intended to mean that there are one or more elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Further, it is to be understood that references to "one embodiment" or "embodiments" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0014] 2 is a schematic diagram of an installation 10 including a cable for use downhole, according to an embodiment of the present disclosure, which is intended to operate at a fluid production site or injection well 12 made in a subsoil 14.

[0015] These operations are applied by the downhole assembly 30 to perform actions and / or measurements at the bottom of the wellbore 12, such as drilling, cutting with a torch, zone isolation operations, impact operations, or further operations to place a tool in place, such as installing a seal gasket or fixing a tool. Such operations may also include formation evaluation, which involves evaluating formation properties with sensors in the downhole assembly. These operations are performed at any point in the wellbore 12, from the surface 16.

[0016] The fluids produced in the well 12 may be, for example, hydrocarbons such as oil or natural gas and / or other output such as steam or water, and the well may be an "injection" well into which liquid or gas is injected. A production conduit may contain one or more different types of fluids.

[0017] The well 12 is formed within a cavity 18 that is located between the earth's surface 16 and a layer of utilized fluid (not shown) that is located deeper within the subsoil 14 formation.

[0018] The well 12 generally comprises an outer tubular duct 20, which is denoted by the term "casing" and is formed, for example, by an assembly of pipes applied to a layer of subsoil 14. The well 12 may also comprise at least one inner tubular duct 22 with a smaller diameter mounted on the outer tubular duct 20. In certain cases, the well 12 is devoid of ducts 20, 22.

[0019] The inner tube duct 22 is generally called the "production conduit". It is formed of a metal assembly of metal tubes. It is pressed inside the outer tube duct 20, for example by a lining 24.

[0020] The wellbore 12 includes a wellhead material at the surface that selectively closes the outer tubular duct 20 and the aforementioned inner tubular duct 22 or each of the inner tubular ducts 22. The wellhead 26 includes a plurality of selective access valves inside the outer tubular duct 20 and inside the inner tubular duct 22.

[0021] The installation 10 includes an intervention and measurement downhole assembly 30 intended to be lowered into the well 12 through the inner tubular duct 22 and a delivery cable 32 for deploying the downhole assembly 30 in the well 12 .

[0022] The intervention facility 10 further includes a sealing and alignment assembly 34 for the cable 32 mounted at the wellhead 26 , an assembly 36 for deploying the cable 32 positioned near the wellhead 26 , and a surface control unit 38 .

[0023] The sealing and alignment assembly 34 may include an airlock 42 mounted to the wellhead 26 to allow for introduction of the downhole assembly 30 into the wellbore 12, and a stuffing box 44 for achieving a seal around the cable 32 and a return wheel 46, each attached to the wellhead 26, for sending the cable 32 back towards the deployment assembly 36.

[0024] The stuffing box 44 may achieve a seal around the smooth outer surface of the cable 32, for example, by means of an annular lining applied around this surface and / or by injecting a fluid between the outer surface and the wall of the stuffing box 44.

[0025] In the so-called "open well" or "open hole" alternative, where there is no casing 20, the assembly 34 is primarily an assembly for aligning the cable and may not include any sealing devices.

[0026] The deployment assembly 36 includes a winch 37A provided with a drum 37B. The winch 37A and its drum 37B are placed on the ground or, optionally, mounted on a vehicle (not shown). A spool sleeve may be fitted around the drum 37B. The winch 37A is capable of winding or unwinding a given length of the cable 32 to control the displacement of the downhole assembly 30 within the well 12 as it moves up or down, respectively. An upper end 41A of the cable may be attached to the drum 37B.

[0027] The surface control unit 38 includes a processor unit 48, a first telemetry unit 50 for communicating with devices located at the well site (e.g., the winder 37B and optionally the downhole assembly 30), and a second telemetry unit 52 for communicating with a computer remote from the well site.

[0028] The downhole assembly 30 includes a hollow case that contains an operating assembly 58, which includes one or more measurement modules and tools, such as impact or drilling tools or sensors. In some embodiments, the downhole assembly can be controlled from the surface by electrical signals transmitted through the cable 32. In this case, the downhole assembly also includes a telemetry module 60 for communicating with the surface control unit 38 via the cable 32 by any communication system.

[0029] The cable 32 extends between an upper end 41A that is attached to the deployment assembly 36, in particular at the surface of the drum 37B, and a lower end 41B that is intended to be introduced into the well 12. The downhole assembly 30 is suspended from the lower end 41B of the cable 32.

[0030] The length of cable 32 taken between end 41A and end 41B can be greater than 1000 m, in particular significantly greater than 1000 m, comprised between 1,000 m and 100,000 m.

[0031] In one embodiment, the cable is a slickline cable, i.e. a cylindrical solid cable with a smooth outer surface 40. In this case, the cable 32 has an outer diameter of less than 8 mm, advantageously less than 6 mm. The central core is formed by a single solid metal cable, denoted by the term "piano wire".

[0032] In another embodiment, cable 32 is a wireline cable including one or more conductors for transmitting downhole power to a downhole assembly.

[0033] Cable embodiments that can be used as facility cable 32 are described below.

[0034] A cable according to a first embodiment of the present disclosure is shown in Figures 3 and 4. As shown in cross section in Figure 3, the cable 100 comprises a core 102, which includes a conductor 104 (at least one of an electrical conductor or an optical conductor, as described in connection with the Background section) and a polymer matrix 106 surrounding the conductor. The core is cylindrical and generally extends several thousand meters along its longitudinal axis L. The core can be an off-the-shelf cable line, a cable line assembly, or a core specially designed for the cable 100.

[0035] The cable 100 also includes two layers of reinforcing elements 107, a first inner layer 108 in contact with the core and a second outer layer 110 in contact with the inner layer 108. Each reinforcing element may include a fiber bundle including one or more reinforcing fibers impregnated with a polymer. In other words, the reinforcing fibers of the fiber bundle may be embedded in a polymer matrix. The reinforcing fibers may be carbon fibers, aramid fibers, basalt fibers, or glass fibers. The polymer may include a thermoset such as an epoxy, benzoxazine, bismaltide, or cyanate ester, and / or a thermoplastic such as a polyketone, including polyetherketone (PEK) or polyetheretherketone (PEEK), polyphenylene sulfide (PPS), or polyetherimide (PEI). The composition of the reinforcing elements 107 may be selected to include 50% to 80% reinforcing fibers and 20% to 50% polymer by volume. The reinforcing element 107 is generally cylindrical with a defined cross section (rectangular, circular, etc.) and, as a core, it is several thousand metres long.

[0036] As can be seen in Fig. 3, each of the reinforcing elements 107 is tubular with a coating 112 made of a thermoplastic material. The coating is applied to the outer surface of the reinforcing element, its entire circumference and length. The composition of the coating may include fluorinated polymers or fluorinated elastomers such as perfluoroalkoxy (PFA), polytetrafluoroethylene (PTFE), polyketones, including polyetherketones (PEK) or polyetheretherketones (PEEK), polyphenylene sulfide (PPS) or polyetherimides (PEI), ethylenetetrafluoroethylene (ETFE), etc. As can be seen in Fig. 3, the coating forms a layer of material on the outer surface of the reinforcing element 107 that surrounds the prepared reinforcing element 107. This differs from the impregnation described above, where the entire element is filled with the impregnation material.

[0037] Such a cable is a composite cable, and since the reinforcing elements (made of fibers and polymers) have a lower density than metallic armor wires (e.g. carbon fiber and PEEK are each about one-sixth as dense as steel), it is possible to significantly reduce the weight of the cable. The mechanical properties of the reinforcing fibers of the reinforcing elements 107, and in particular their high strength, make it possible to optimize the mechanical properties of the cable, thereby enabling the cable to perform downhole operations.

[0038] The reinforcing elements 107 are arranged on the cable such that each reinforcing element is capable of moving relative to the core and at least the other reinforcing elements, in particular relative to all other reinforcing elements. In particular, each reinforcing element is capable of moving axially relative to the core and at least the other reinforcing elements. In this embodiment, this is achieved because there are no bonds between adjacent reinforcing elements or between each reinforcing element and the core. The fiber bundles are not embedded in a common polymer matrix that fixes the fiber bundles relative to the core and other fiber bundles that are placed in the common polymer matrix. In particular, in this embodiment, each reinforcing element is an independent part relative to the other reinforcing elements and is not connected to adjacent reinforcing elements or to the core, i.e. each reinforcing element is not connected to another reinforcing element by any material or mechanical bond or connection, including gluing, welding, screwing, etc.

[0039] As can be seen in figure 4, the reinforcing elements 107 of the first layer 108 may each be wound helically around the cable with the same winding angle, arranged so that each reinforcing element of the layer is in contact with two adjacent reinforcing elements as with the core. The winding angle is the angle between the reinforcing element and the longitudinal axis. An example of a winding angle α for a cable of the prior art is shown in figure 1. In the embodiment of figures 3 and 4, the angle may be set between 5° and 30°, in particular below 20°.

[0040] The thermoplastic coating 112 applied to the reinforcing elements 107 is a lubricant that makes it possible to reduce wear and friction caused by movement between the reinforcing elements as well as the overall friction of the cable in the open hole.

[0041] Moreover, reinforcing elements that are able to move relative to each other take advantage of the good properties of their reinforcing fibers (i.e. high strength and low density) without creating a solid cylinder and maintain the ability of each reinforcing element not to be damaged when bent, which is necessary for such cables stored on drums. As can be seen in FIG. 4, since the cable is wound around a cylindrical element and each of the reinforcing elements 107 has one or more degrees of freedom, in particular at least an axial degree of freedom, relative to the other reinforcing elements, the arrangement of the reinforcing elements 107 can be slightly modified to minimize binding when bending the cable. For example, it can be seen in FIG. 4, where the reinforcing elements move away from each other when bent at locations 114 and 116. This arrangement therefore allows the cable to have a longer life and to better maintain its mechanical properties even when not in use and when wound on a drum for long periods of time.

[0042] Moreover, with regard to rapid gas decompression, because the reinforcing elements are not connected together (i.e., embedded in a matrix), gas can come out of the cable fairly quickly as it is pulled out of the hole (and passes from high wellbore pressure to atmospheric pressure) without any sudden damage to the cable occurring. In other words, the cable does not tend to trap gas inside it, and therefore does not experience the phenomenon of rapid gas decompression as it is conveyed out of the hole and undergoes a significant pressure reduction.

[0043] When a cable includes more than one layer, the wrap angle of the reinforcing elements of one layer may be different from the wrap angle of the reinforcing elements of another layer. Furthermore, the wrap direction of the reinforcing elements may be different for each layer, as can be seen in FIG. 4, where the inner layer 108 is visible due to the spread of fibers of the outer layer 110 in zone 116. In other words, the representation of the wrap angle in trigonometric space may be different for the first layer 108 and the second layer 110. In certain embodiments, the wrap angle of the first layer (with respect to the longitudinal axis of the cable) is opposite to the wrap angle of the second layer.

[0044] As shown in Figure 3, the tubed reinforcing elements may conform to match the contact surface (i.e., outer surface) of the core and the contact surface of the adjacent reinforcing elements, particularly for the first layer of fibers 108. In Figure 3, the reinforcing elements of the first layer take a substantially trapezoidal shape in this configuration. Such conformance may be achieved by applying compression to the cable, as will be described in more detail in connection with the manufacturing method of the fibers.

[0045] Such a fit allows the cable to be more easily sealed when in the open hole. Indeed, as explained in connection with FIG. 2, when the cable is lowered in the open hole, it passes through a stuffing box 44 which provides a pressure barrier between the wellbore (high pressure) and the surface (low pressure). The stuffing box is shown in more detail in FIG. 2B. It includes a packer (or packing) 400 which applies high pressure around the entire circumference of the cable, as indicated by the arrows 402. The packer 400 thus compresses the reinforcing elements 107 against the core, so that the reinforcing elements are pressed against the core and / or against each other. This is particularly shown in FIG. 5, which shows diagrammatically the force 120 that each of the tube-equipped reinforcing elements 107 (represented by a trapezoid) exerts on the adjacent elements when it is subjected to compression 122 around its entire circumference. Such compression is maintained in the open hole by the high pressure of the open hole. Considering the trapezoidal shape of the reinforcing elements, the entire periphery of the reinforcing elements of the first layer is in contact with the adjacent elements (core and adjacent reinforcing elements), protecting the barrier between the core and the wellbore fluids and providing sealing, even though the reinforcing elements are not embedded in the polymer matrix.

[0046] Furthermore, such cables do not require any grease injection to obtain air tightness at the wellhead, since the ability of the reinforcing elements to move relative to one another and the ability of the tube around each reinforcing element to deform allows the cable to adapt to the shape of the packer (or packing) when compressed.

[0047] In an alternative embodiment, the coatings 112 of at least two adjacent reinforcing elements 107 may be joined to one another, for example by plastic welding. In particular, the thermoplastic coating of a first tubed reinforcing element is generally joined, at least locally, to the thermoplastic coating of a second tubed reinforcing element adjacent to the first tubed reinforcing element. In this case, the reinforcing elements are still considered to be able to move relative to one another, since the reinforcing elements 107 may be configured to move relative to the coatings 112, in particular to slide within the tube. The coating may in particular comprise a fluorinated polymer or fluorinated elastomer that does not adhere strongly to the reinforcing elements.

[0048] Such relative movements of the reinforcing elements are made possible by the structure of the cable forming a non-uniform matrix, i.e. the non-uniform matrix has non-uniform properties (particularly the stiffness modulus) with a higher stiffness modulus for the reinforcing elements 107 and the core and a lower stiffness modulus for the bonded coating 112. The bonded coating is thus able to damp the axial restraint and allows a relative axial movement between the reinforcing elements 107 without breaking. The materials of the reinforcing elements 107 and the coating 112 can be chosen such that the ratio between the stiffness modulus of the coating and the stiffness modulus of the reinforcing elements is between 0.05 and 0.5, in particular between 0.1 and 0.2. Likewise, such a structure also makes it possible to exploit the good properties of the reinforcing elements (i.e. high strength and low density) while at the same time allowing a relative axial movement of the reinforcing elements without breaking the cable. The relative movements (particularly the relative axial movements) between the reinforcing fibers are about 10 to 100 times higher than when the fiber bundles are embedded in a homogeneous matrix (in particular a homogeneous matrix of a thermosetting material). It should therefore be understood that when it is defined that the reinforcing elements are capable of moving relative to one another, the relative movement of the reinforcing elements, including the bundles of fibers that do not break, is at least twice as high as if the bundles of fibers were embedded in a uniform matrix forming a rigid cylinder. In other words, this construction allows for a compromise between the stiffness and strength required for the cable to withstand harsh downhole conditions, and flexibility, allowing the cable to be wound and unwound on a drum without damage.

[0049] Such an embodiment in which the coatings 112 tubing the reinforcing elements 107 are bonded together is shown in FIG. 15. The cable of FIG. 15 includes a core 102 and a first layer 108 and a second layer 110 of tubed reinforcing elements disposed around the core, as in FIG. 3. As disclosed in connection with the above embodiment, the reinforcing elements 107 tubularized with coatings 112 conform to contact the corresponding surfaces of adjacent reinforcing elements. However, as can be seen in FIG. 15, in order to bond the coatings 112 of adjacent reinforcing elements 107, the space 130 between the tubes of the first adjacent coating and the second adjacent coating 112 is filled with a material 132. In this embodiment, the material 132 fills the entire space, but the space may be partially filled and the coatings 112 of adjacent fibers are locally bonded. The material 132 filling the space can be the material of the coating 112, especially when the cable is heated so that melting of the coating 112 of the adjacent tubes joining both coatings together (i.e. the first coating and the second coating tubing the first reinforcing fiber and the second reinforcing fiber) occurs. In an embodiment, the material filling the space can be a material different from the material of the coating. The cable of FIG. 15 also includes an outer jacket 140, which can be made of a polymer such as a thermoplastic material. The material of the outer jacket 140 can be chosen to have a higher melting point than the thermoplastic coating 112 of the reinforcing element 107. Such a polymer can be of the same type as the polymer of the coating, but with a higher melting point (e.g. at least 10° C. higher). For example, the coating of the reinforcing element can be made of ETFE LMT (i.e. low melting point), while the outer jacket is made of ETFE HMT (high melting point). As will be described later in connection with the manufacturing process, such an embodiment allows for the formation of bonds or cohesion between the coating 112 of the reinforcing element and the outer jacket 140, between the coatings 112 of adjacent reinforcing elements, locally or generally around the entire circumference of the reinforcing element and along the entire length of the reinforcing element, while preventing loss of material. Such an embodiment may allow for a more efficient barrier against gases.

[0050] The present disclosure also includes additional embodiments shown in Figures 6 to 10. Only the differences between these embodiments and the first embodiment are highlighted.

[0051] As shown in the embodiment of FIG. 6, the cable 150 includes a core 152 that includes seven conductors 154. In this embodiment, the cable is a wired hepta cable and the core is a standard core for such cables. Furthermore, in FIG. 6, the reinforcing element 156 is flat and has a rectangular cross section with a length at least five times greater than its width, and is also spirally wrapped around the core and tubed with a thermoplastic coating 158. A reinforcing element 156 with such a cross section allows for a smaller cable radius. However, it should be noted that other cross sections of the reinforcing element (triangular, polygonal, trilobal, etc.) are also part of this disclosure.

[0052] In the embodiment of Figure 6, the cable includes only one layer of reinforcing elements wrapped around the core. Note that the cable may include any number of reinforcing element layers, not just one or two.

[0053] In another embodiment, the reinforcing elements of at least one layer may be arranged as a material including tubular reinforcing elements intertwined in different orientations. For such a material, reinforcing elements with different winding directions cross in some places, but are still able to move relative to each other, especially axially. In an example of such a material, as shown in FIG. 7, the reinforcing element 170 is braided and has reinforcing elements of two different winding orientations 172, 174. In the example of FIG. 7, the percentage of reinforcing elements in each of the orientations 172, 174 is about 50%. However, any other method for intertwining the reinforcing elements is considered part of the present disclosure. For example, the material may include reinforcing elements of three or more orientations, or may have reinforcing elements of each orientation in different proportions. Furthermore, when the cable includes several layers, only one of the layers (e.g., the outer layer) may be made of such a material of intertwined reinforcing elements.

[0054] In another embodiment shown in FIG. 8, the cable 200 includes an outer jacket 202. The outer jacket can be, for example, a thermoplastic jacket made of perfluoroalkoxy (PFA), polytetrafluoroethylene (PTFE), and / or polyketone, including polyetherketone (PEK) or polyetheretherketone (PEEK), and / or fluorinated polymers or fluorinated elastomers, such as polyphenylene sulfide (PPS) and / or polyetherimide (PEI). The outer jacket 202 can be, for example, a thin metal tube crimped over the cable or metal braid. The jacket allows the cable to add protection from wellbore fluids, further reduces friction, and can hold the reinforcing elements together, especially in case of cable damage. In an embodiment, the jacket 202 can be porous to avoid trapping gas within the cable, as described in connection with the rapid gas decompression phenomenon. In the embodiment of FIG. 8, the cable includes four layers 204-210 of flat reinforcement elements, which are represented diagrammatically, although an outer jacket may be placed over a cable having any configuration and any number of layers of reinforcement elements.

[0055] In an additional embodiment shown in FIG. 9, the cable 220 may include at least one or more metal wires 222, e.g., made of copper or aluminum or an alloy containing copper and / or copper and / or aluminum, and one or more optical fibers 224 wrapped around a core 226, such that each of the metal wires 222 or optical fibers 224 can move relative to the core and, in turn, relative to the stiffening element. The optical fibers and / or metal wires 222, 224 may be wrapped around the core in the same layer as the stiffening element 228, as shown here for the metal wire 222. Alternatively, they may be placed in different layers and also helically wrapped around the core, as shown in FIG. 6 for the optical fiber 224. In another configuration, the optical fibers and / or metal wires 222, 224 may extend parallel to the longitudinal axis of the core. The metal wires and / or optical fibers wrapped around the core may form one or more electrical conductors and / or light conductors of the cable.

[0056] Arranging the metal wires or optical fibers in a different layer from the reinforcing elements makes it possible to set the winding angle of each type of element independently, which can be useful, for example, when the mechanical properties of the elements are not the same or when specific requirements apply to one of the elements.

[0057] Furthermore, the optical fibers and / or metal wires are preferably encased in a thermoplastic coating 230 as a reinforcing element to limit friction between the different elements wrapped around the core.

[0058] In the embodiment of FIG. 9, the core does not include any conductor. As explained above, the conductor may actually be wound around the core, in which case the core may have only a mechanical function. The conductor may be provided by one or more metal wires when these metal wires are connected at the surface. In such a case, the metal wires may transmit power and / or communication signals from the surface to the downhole assembly or from the downhole assembly to the surface. However, the metal wires may not be used as conductors, but only as another type of reinforcement. Furthermore, the core may include a conductor and the metal wires may be used as additional conductors.

[0059] In the embodiment of FIG. 9, the core may be made of a material with a high Young's modulus (a polymer associated with carbon fibers with a high Young's modulus or a polymer that includes metal wires in particular). The cable thus comprises a material with a high Young's modulus in the center and a low Young's modulus near the outer surface (such as a polymer associated with carbon fibers with a low Young's modulus), making the center of the cable more flexible. Indeed, such a configuration allows the elements located at the outer diameter of the cable (reinforcing elements or metal wires) to stretch more during bending (i.e. when the cable is stored in the drum) than the core (designed to have a high Young's modulus), since the outer elements are subject to more constraint when bending the cable. A core with a higher Young's modulus is stiffer. Thus, for the same overall cable stiffness, such a configuration allows the cable to resist bending more and to have a longer cable life.

[0060] The possibility of locating the conductors elsewhere than within the core allows for greater flexibility in the design of the core to obtain such configurations. For example, the core may also include one or more reinforcing elements (comprising at least a bundle of reinforcing fibers and optionally a polymer matrix) that are also tubed with a thermoplastic coating. The reinforcing elements (i.e., the number and type of fibers, the type and portion of the polymer matrix (if present)) may be designed to optimize the properties of the core (especially the Young's modulus).

[0061] The optical fiber 226 may enable one or more properties of the cable to be measured in order to predict when maintenance of the cable will be required or one or more properties of the well site and / or formation. To make such measurements, the fiber may be connected to an interrogator and detector to be part of a distributed acoustic system (DAS), for example as described in U.S. Patent No. 8,225,867.

[0062] In the embodiment of Figure 9, the cable also includes an outer liner 232 and a bare metal wire 234 disposed about the liner, as disclosed in connection with Figure 8. Such metal wire 234 provides an efficient electrical ground for the cable, and may either extend in a direction parallel to the longitudinal axis of the cable, or may be wrapped around the outer jacket of the cable.

[0063] In another embodiment shown in Figure 10, a cable 240 includes a core 242 and a tubed reinforcement element 244 that runs all along the length of the core. A jacket 246 covers and holds the reinforcement element together. In this case, the reinforcement element may be positioned such that the core is not located in the center of the cable, but closer to the side of the cable to facilitate access to the core and maintenance and repair of the conductor(s) 248 located within the core.

[0064] In another embodiment, metal wires and / or optical fibers can be incorporated into the reinforcing element. Such reinforcing elements can be arranged around the core or can be part of the core. An example of a reinforcing element 250 is shown in FIG. 11. The reinforcing element 250 includes a metal wire 252 (which can be used as a conductor as described in connection with FIG. 9) in its center. A fiber bundle 254 can be arranged around the metal wire and a polymer matrix can be impregnated into the fiber bundle and the conductor. As described in connection with other embodiments, the reinforcing element is tubed by a thermoplastic coating 256. Such a reinforcing element can include any arrangement of metal wires and fiber bundles (e.g., the metal wire is not arranged in the center). When using a metal wire as a conductor, the metal wire can be used to insulate it from other conductors, since the thermoplastic coating and the polymer matrix are insulating materials. The metal wire(s) can be replaced by one or more optical fibers or can be embedded with the optical fibers in the fiber bundle. Such an architecture makes it possible to collect several functions in the reinforcing element (electrical and / or optical functions, as well as mechanical functions) and to optimize the dimensions of the cable.

[0065] An example of a cable 260 including such a reinforcing element is shown in FIG. 12. Such a cable 260 includes a core 262 having a reinforcing element including a fiber bundle of reinforcing fibers and seven conductors 266 made of metal wire embedded in the bundle. The conductors are made of metal wire. The reinforcing elements are tubular with a thermoplastic coating 268. The cable also includes a first layer of reinforcing elements 270, 272 tubular with a thermoplastic coating 276 disposed around the core. The reinforcing elements 272 include optical fibers 274 embedded in the bundle of reinforcing fibers. In this embodiment, the reinforcing elements 262 are of larger dimensions than the reinforcing elements 270, 272 of the layer surrounding the core. More generally, the reinforcing elements of a cable may have different sizes and shapes.

[0066] All the cables according to the above embodiments are described as wireline cables, in particular the armored wires are replaced by fiber, which allows to reduce the cable density and the weight of the cable. However, such cable designs may also be applicable to other downhole cables such as slickline cables, as well as cables with applications on the surface, in well site applications, or in other fields. In this case, the dimensions of the single wires may be smaller compared to current cables, and it is also possible to reduce the cable weight.

[0067] The cables described in this disclosure may also be used for other downhole applications.

[0068] Disclosed below are methods for manufacturing the cable and methods for operating the cable.

[0069] A method 300 for manufacturing a cable is described with reference to Figures 13 and 14. In the flow chart of Figure 10, optional operations are represented by dashed blocks while mandatory operations are represented by solid blocks. Figure 14 shows a portion of an exemplary manufacturing line 350 for a cable according to the present disclosure.

[0070] The method 300 first includes preparing the reinforcing elements (block 302). To perform this operation, each reinforcing element is individually tubed with a thermoplastic coating, generally in an extrusion process (block 306). The fiber bundles of the reinforcing elements may also be impregnated with a polymer matrix before being coated by passing the fibers through a polymer bath (block 304). The reinforcing elements after operation 304 may be called prepregs. During or before impregnation, the fiber bundles may also be conformed so that the prepregs have a predetermined section (such as cylindrical or flat). If the reinforcing elements include metal wires and / or optical fibers, the fiber bundles are placed around the metal wires and / or optical fibers before impregnation. Once the thermoplastic tubes are extruded into the reinforcing elements, such prepared reinforcing elements are stored in drums. When metal wires or optical fibers are included in the cable, they may be prepared using the same tubing operation as described in operation 306 and, once tubed, stored in a drum.

[0071] Next, the manufacturing method includes providing a layer of reinforcing elements on the core (block 308). The core can be prepared separately, for example, if it is composed of several materials, but can be a standard core. If the core includes reinforcing elements, it is prepared according to the same preparation operations described above.

[0072] The manufacturing method includes winding the tubed reinforcing elements around the core, for example using a cable assembly machine such as a planetary assembly machine 352 and a die 354 to helically wind the reinforcing elements (block 310) around the core, resulting in a regular shape for the cable. In the embodiment shown in Figure 14, each and every reinforcing element of the core is unwound from different drums 356, 358 and passes through a planetary machine 352 that allows the reinforcing elements to rotate only while the core translates. Alternatively, the fibers can be braided as described above.

[0073] Once the reinforcing elements are wrapped around the core, the manufacturing method may also include conforming the reinforcing elements to conform to the surfaces of the core and adjacent reinforcing elements (block 312), for example using compression rolls 362 and heaters 360 to facilitate deformation of the polymer matrix (if present) by applying compression to the cable once assembled.

[0074] In this case, high pressure is applied all around the cable, causing the tubular reinforcing elements, which are soft since the polymer matrix of the prepreg is uncured, to deform and conform to and press against adjacent elements (i.e., core and fibers).

[0075] The manufacturing method may also include at least locally joining the thermoplastic coating of the first reinforcing element with tube to the thermoplastic coating of the second reinforcing element with tube, for example by increasing the temperature above the melting point of the thermoplastic coating, so that the coatings of the two adjacent reinforcing elements with tube melt and join in the molten state by plastic welding. This may be done, for example, by using a heated roller. This may be done once the reinforcing elements with tube are fitted or during the fitting of the reinforcing elements with tube. In a variant, a filler material may be provided to join the coating material of the reinforcing elements with tube by plastic welding. In other words, the coatings of the first and second reinforcing elements may be joined by plastic welding with or without the intervening filler material.

[0076] The manufacturing also includes curing the polymer matrix of the reinforcement elements with heater 360 when the reinforcement elements are impregnated, after the reinforcement elements have been assembled on the core and optionally fitted and / or bonded (block 314). Indeed, uncured reinforcement elements assembled on the cable are more flexible and can be assembled and, if necessary, fitted more easily than if the reinforcement elements were individually cured after impregnation. Once the reinforcement elements are cured, they have better mechanical properties than the uncured reinforcement elements. The core and reinforcement elements can be stored in a drum.

[0077] If there are different layers of fibers on the cable, the same operations are resumed with the cable having the core and the wrapped fibers in the center of the cable assembly machine. When there are several layers of reinforcing elements, the optional fitting and curing operations can be performed only once once all the layers of reinforcing elements have been assembled on the core. The manufacturing method can also include providing an outer jacket on the cable, for example by crimping a metal tube or by extruding a thermoplastic outer layer (block 316). This operation is not represented in the manufacturing line of FIG. 11. Alternatively, the outer jacket can be provided on the cable at once for all layers (if there are several layers) and then the curing and / or fitting operations can be performed.

[0078] In certain embodiments where the outer jacket has a higher melting point than the coating of the strength elements, the manufacturing process for the cable may include the following. in particular by extruding the outer jacket onto the reinforcing elements, since in this case the melting point of the outer jacket is higher than the melting point of the coating of the reinforcements, such extrusion also results in intimate contact between the coating material of each reinforcement and the outer jacket material, at least locally, by means of plastic welding, when the coating material melts during extrusion. - for example, conforming of the cable between rollers at a temperature between the melting point of the coating and the melting point of the outer jacket. During conforming, as explained above, the reinforcing elements deform to conform to the contact surface of the adjacent tubed reinforcing elements, and the tubed coatings around each reinforcing element are joined and bonded to each other at least locally by plastic welding, while the shape of the outer jacket is maintained. In certain embodiments, instead of or in addition to the rollers, high tensions can be used on the cable. Such bonding from one reinforcing element to another allows gas to be blocked more efficiently, at least since the number of gaps between the reinforcing elements is significantly reduced.

[0079] Once the cables have been fitted and / or joined, the matrix of reinforcing elements may be cured as described above.

[0080] As explained in relation to all the above embodiments, the cable according to the present disclosure has mechanical properties adapted for downhole use, in particular with high strength and good resistance to bending stresses, while allowing to reduce the weight of the cable and thus the power required to operate the cable and the footprint of the well site equipment to be significantly reduced. This cable can be used in other technical fields.

[0081] The present disclosure relates to a cable having at least a conductor, the cable including a core and a plurality of reinforcing elements disposed around and covering the core, each reinforcing element including at least a bundle of reinforcing fibers including at least one fiber and a thermosetting matrix impregnating the bundle of fibers, and individually tubed with a thermoplastic coating.

[0082] The present disclosure also relates to a cable including a core and a plurality of reinforcing elements disposed around and covering the core, each reinforcing element including at least a bundle of reinforcing fibers including at least one fiber, each reinforcing element being individually tubed with a thermoplastic coating, the cable being configured such that each reinforcing element is capable of moving relative to the core and at least another reinforcing element.

[0083] The following features may be applied to any of the cables. the reinforcing elements are wound helically around the core. In such an embodiment, the winding angle of the reinforcing elements is less than 30°, preferably 20°, the winding angle being the angle between the longitudinal axis of the core and the fibers. The core includes at least a conductor. At least one conductor is wound around the core, in particular at least one of the conductors is embedded in at least one bundle of reinforcing fibers of the reinforcing element. At least the conductors, in particular each of the conductors, are electrical conductors, such as metal wires, or optical conductors, such as optical fibres. The core comprises at least a reinforcing element. The thermoplastic coating comprises at least one of the following materials: perfluoroalkoxy (PFA), polytetrafluoroethylene (PTFE), polyketones such as polyetherketone (PEK) or polyetheretherketone (PEEK), fluorinated polymers or fluoroelastomers such as polyphenylene sulfide (PPS) or polyetherimide (PEI). Each reinforcing element comprises a polymer (in particular a thermosetting matrix) that impregnates a bundle of fibers. At least the reinforcing fibers may be carbon fibers, glass fibers, aramid fibers, or basalt fibers. The cable comprises a layer comprising tubed reinforcing elements, each reinforcing element of the layer being in contact with two adjacent reinforcing elements and the core. In this embodiment, at least one tubed reinforcing element may be adapted to match the contact surfaces of the core and the adjacent reinforcing elements. For example, at least two adjacent tubed fibers may have a trapezoidal shape. - the cable includes a first layer including a first plurality of reinforcing elements wrapped around a core and a second layer including a second plurality of reinforcing elements wrapped around the first layer, in this embodiment, the wrap angle of the first plurality of reinforcing elements is different from the wrap angle of the second plurality of reinforcing elements. The cable includes an outer jacket covering the plurality of reinforcing elements. The outer jacket may include a thermoplastic layer or a metal tube. The cable may include metal wires or optical fibers embedded in a bundle of reinforcing fibers. Alternatively, the optical fibers or conductors may be tubed with a thermoplastic coating. In this embodiment, the cable may include a first layer including a first plurality of reinforcing elements wrapped around a core and a second layer including a second plurality of reinforcing elements wrapped around the first layer, with the optical fibers or conductors being wrapped as part of the first or second layer. At least a number of the reinforcing elements are flat reinforcing elements. A material of reinforcing elements having multiple orientations is arranged around a core. -The cable is a wireline cable for downhole use. The cable is configured such that each of the tubed reinforcing elements is capable of moving (particularly axially) relative to the core and at least another reinforcing element. The tubular reinforcing elements are independent parts, each of the tubular reinforcing elements is not connected to other reinforcing elements. Alternatively, the thermoplastic coating of the first tubular reinforcing element is at least locally joined to the thermoplastic coating of the second tubular reinforcing element, in particular by plastic welding, with or without the interposition of a filler material. the ratio of the modulus of rigidity of the thermoplastic material attaching the tube to the reinforcing element to the thermosetting material impregnating the fiber bundles of the reinforcing element is comprised between 0.05 and 0.5, preferably between 0.1 and 0.2; The cable comprises an outer jacket surrounding the tubular reinforcing element, in which case at least the thermoplastic coating of the tubular reinforcing element may be at least locally bonded to the outer jacket, the material of the outer jacket having a higher melting point than the material of the coating of the tubular reinforcing element.

[0084] The present disclosure also relates to a drilling equipment including a winch having a drum for winding a cable, a downhole tool configured to be lowered in a wellbore, and a cable according to any of the embodiments described above having a first end wound around the drum and a second end having the downhole tool attached.

[0085] The present disclosure also relates to a method of manufacturing a downhole cable, the method including extruding a thermoplastic coating around each of a plurality of reinforcing elements of a plurality of reinforcing elements to form a tube around each reinforcing element, each reinforcing element including at least a bundle of reinforcing fibers including one or more reinforcing fibers, and disposing the plurality of tubed reinforcing elements around a core so as to cover the core, whereby each reinforcing element is capable of moving relative to the core and at least another reinforcing element.

[0086] In one embodiment, the manufacturing method includes impregnating a bundle of reinforcing fibers with a polymer before extruding the thermoplastic coating, and curing the tubed reinforcing element after placing the fibers around the core.

[0087] In some embodiments, disposing the reinforcing element includes helically wrapping the reinforcing element around the core.

[0088] The present disclosure also relates to a method of manufacturing a cable comprising: a. forming a plurality of reinforcing elements, each reinforcing element comprising impregnating a bundle of reinforcing fibers comprising one or more reinforcing fibers with a thermosetting matrix; b. extruding a thermoplastic coating around each of the plurality of reinforcing elements to form a tube around each reinforcing element; c. disposing a plurality of tubular reinforcing elements around the core so as to cover the core; d. Curing the thermosetting matrix of the tubular reinforcing element once positioned about the core.

[0089] In one embodiment, the manufacturing method includes applying compression to the cable prior to curing, thereby conforming the reinforcing elements to conform to the surfaces of the core and adjacent reinforcing elements.

[0090] In an embodiment, the manufacturing method comprises at least locally bonding the thermoplastic coating of the first tubular reinforcing element to the thermoplastic coating of the second tubular reinforcing element, in particular during or after fitting, before curing, preferably by heating the cable, but such bonding is carried out before curing.

[0091] In one embodiment, the method includes forming an outer jacket around the tubed reinforcing element, the outer jacket being made of a material having a higher melting point than the thermoplastic coating that attaches the tube to the reinforcing element, and the fitting and / or bonding being performed after forming the outer jacket. In this embodiment, the outer jacket may also be bonded, at least locally, to one or more of the coatings of the reinforcing element.

Claims

1. A cable, A core, a layer including a plurality of reinforcing elements disposed about and in contact with the core; Equipped with Each reinforcing element is one or more metal wires; a plurality of reinforcing fibers disposed about the one or more metal wires; Contains the plurality of reinforcing fibers and the one or more metal wires are impregnated with a thermosetting matrix; Each reinforcing element is individually tubed with a thermoplastic coating A cable characterized by:

2. At least one conductor Further comprising: The at least one conductor is an electrical conductor or a light conductor.

2. The cable according to claim 1 .

3. Each reinforcing element is adapted to match a contact surface of the core and a contact surface of an adjacent reinforcing element.

2. The cable according to claim 1 .

4. A first layer including the plurality of reinforcing elements; a second layer including a second plurality of reinforcing elements disposed about and in contact with the first layer; 4. The cable of claim 3, further comprising:

5. Each reinforcing element is capable of moving axially relative to the core and at least another reinforcing element.

4. The cable according to claim 3.

6. The thermoplastic coating of a first reinforcing element is at least locally bonded to the thermoplastic coating of a second reinforcing element.

6. The cable according to claim 5.

7. The thermoplastic coating of the first reinforcing element and the thermoplastic coating of the second reinforcing element are joined by plastic welding.

7. The cable according to claim 6.

8. The ratio of the modulus of rigidity of the thermoplastic coating to the modulus of rigidity of the thermosetting matrix is ​​0.05 to 0.

5.

2. The cable according to claim 1 .

9. an outer jacket surrounding said layer of said plurality of reinforcing elements; 2. The cable of claim 1, further comprising:

10. The thermoplastic coating of one or more of the reinforcing elements is at least locally bonded to the outer jacket.

10. The cable of claim 9.

11. The outer jacket has a higher melting point than the thermoplastic coating.

10. The cable of claim 9.

12. 1. A drilling installation comprising: a winch having a drum for winding the cable; a downhole tool configured to be lowered into the wellbore; a cable having a first end and a second end; Equipped with the first end of the cable is wrapped around the drum; the downhole tool is attached to the second end of the cable; The cable further comprises: A core, a layer including a plurality of reinforcing elements disposed about and in contact with the core; Including, Each reinforcing element is one or more metal wires; A plurality of reinforcing fibers; Contains the plurality of reinforcing fibers and the one or more metal wires are impregnated with a thermosetting matrix; Each reinforcing element is individually tubed with a thermoplastic coating 1. A drilling facility comprising:

13. 1. A method of manufacturing a cable, comprising the steps of: forming a plurality of reinforcing elements, each reinforcing element comprising: disposing a plurality of reinforcing fibers around one or more metal wires; and impregnating the plurality of reinforcing fibers and the one or more metal wires with a thermosetting matrix; extruding a thermoplastic coating around each reinforcing element of the plurality of reinforcing elements to form a tube around each reinforcing element; disposing the plurality of reinforcing elements around the core so as to contact the core; curing the thermosetting matrix after disposing the plurality of reinforcing elements about the core; 1. A method for manufacturing a cable comprising:

14. before the step of curing the thermosetting matrix, compressing the cable to conform the reinforcing elements to the contact surfaces of the core and adjacent reinforcing elements; 14. The method of claim 13 further comprising:

15. bonding the thermoplastic coating of a first reinforcing element to the thermoplastic coating of a second reinforcing element by heating the cable prior to the step of curing the thermosetting matrix.

15. The method of claim 14 further comprising:

16. forming an outer jacket around the reinforcing element. Further comprising: the outer jacket having a higher melting point than the thermoplastic coating; At least one of the matching step or the bonding step occurs after the outer jacket is formed.

16. A method for manufacturing a cable according to claim 15.

Images