Cable assemblies may be used in various types of wellbore applications. Generally, the cable assemblies may be used to transmit power, information, and/or commands through a central conductor with a signaling current. Frequently, the use of cable assemblies may be limited by distance. As signal currents move away from the original source the signal current may attenuate and dissipate over long distances. Materials used within a cable assembly may be designed for protection against a downhole environment, which may not be good conductors and/or do not adequately prevent attenuation. These materials may hinder the movement of the signal current, which may cause signal currents to dissipate and attenuate. Consequently, this effect may result in degraded, noisy, and/or lost signals. This may be of particular concern in certain types of cable assemblies, for example, cable assemblies that may be disposed in deep wellbores that traverse long distances.
Examples of past techniques for addressing these issues may include thicker cables and avoiding long cable assemblies. However, these solutions do not allow for sufficient flexibility with regards to deeper wells as space may be limited for larger cables and attenuation may continue to plague signal current transmission downhole. Furthermore, cost may increase as larger cables may require alternate connections with downhole equipment, which may require alterations to current connections with downhole equipment.
These drawings illustrate certain aspects of some of the embodiments of the present invention, and should not be used to limit or define the invention.
Disclosed are systems, assemblies, and methods that may utilize an extra conductive layer within a cable assembly for the transmission of signal currents. The signal currents may be transmitted downhole and/or uphole. More particularly, systems, assemblies, and methods may be provided for applying an extra conductive layer within the cable assembly and using the cable assembly containing extra conductive layer within wellbore applications. The term “cable,” as used herein, refer to physical structures that guide high frequency signaling currents. The cable may be used in any application requiring the transmission of power and/or information between two locations. A protective covering may be used to protect the cable and its components from external forces and external materials. One of the many potential advantages of the systems, assemblies, and methods described herein is that the cable with extra conductive layer may be able to replace existing cable assemblies used in a completed well without alterations to downhole equipment and/or existing wellbore methods, assemblies, and/or services. The extra conductive layer may provide a reduction in the attenuation of a communication signal, which may allow the cable assembly to be disposed deeper into a wellbore. Additionally, the cable assembly may be used with current downhole equipment and surface controls, which may prevent costs from increasing during deeper wellbore applications.
Any suitable technique may be used for transmitting signals from downhole equipment 110 to surface 112. As illustrated, cable assembly 104 may transmit data from downhole equipment 110 to information handling system 120, disposed on surface 112. Information handling system 120 may include a processing unit 122, a monitor 124, an input device 126 (e.g., keyboard, mouse, etc.), and/or computer media 128 (e.g., optical disks, magnetic disks) that may store code representative of the methods described herein. Information handling system 120 may be disposed on downhole equipment 110 or otherwise positioned on surface 112. Information handling system 120 may act as a data acquisition system and possibly a data processing system that analyzes information from downhole equipment 110. This processing may occur at surface 112 in real-time. Alternatively, the processing may occur at another location after recovery of downhole equipment 110 from wellbore 116 or the processing may be performed by an information handling system 120 in wellbore 116, which may be transmitted in real-time.
Extra conductive layer 138 may comprise copper, brass, bronze, or any other conductive material and in any form such as mesh, strips, and/or tape. In examples, extra conductive layer 138 may be in contact with the inner diameter of outer conductive casing 140 and may act as a ground path for cable assembly 104. The outer conductive casing 140 may be incoloy, inconels, duplex stainless steels, 300 series stainless steels and/or other types of conductive materials. Two extra conductive layers 138 may be pulled together and/or forced together during the manufacturing process. For example, signaling currents may be direct current and/or alternating current. Thus, signaling currents transmitted using direct current may work well when production tubing 5 acts as a ground path. However, signaling currents transmitted using alternating currents may attenuate in production tubing 5 before the signal may be recorded, which may lead to a loss of information. In downhole operations, alternating current may be used, as it may be easier on equipment to transmit information efficiently. Extra conductive layer 138 may be a medium of low resistance, which may allow signaling currents to travel further without attenuating, preventing the loss of information. In examples, where cable 130 without extra conductive layer 138, the skin effect may lead to attenuation of signaling current. The skin effect may be defined as when signaling currents are largely confined to the top most surface layers of a conductor, the proportion of the total current carried by a specified thickness of the conductor may be dependent on the frequency, and the dimension and electrical properties of the conductor.
Signaling currents may be described as a way to delivery data in the form of alternating voltage and current along the cable, where two conductive layers may form a waveguide. To send binary information along cable 130, a certain frequency may be used for ‘0’, while another frequency and/or no modulation may be used for ‘1’. The carrier frequency may be high enough for the cable assembly 104 to be regarded as a waveguide when the wavelength of the alternating signal may be comparable to the cable length. At this conditions, Maxwell equation may be used to apply analysis on electrical and magnetic field for attenuation of the signals. In general, the alternating current signal at this frequency may not use the advantage of a large cross section of the metal outer conductive casing 140, but instead, it may traverse through a very thin layer at the surface (skin effect).
In examples, the degradation of extra conductive layer 138 may be prevented by outer conductive casing 140. Outer conductive casing 140 may protect extra conductive layer 138 from downhole conditions and elements. Outer conductive casing 140, referring to
A method for using a cable assembly 104 in a well may be provided. The method may comprise disposing a cable assembly 104 downhole within a well. In examples, cable assembly 104 may be inserted into completed wells and/or wells being drilled. Cable assembly 104 may be disposed on production tubing 106, casing 108, and/or on a drill string. In examples, cable assembly 104 may attach to any number and/or types of downhole equipment 110 and may provide power and communication to downhole equipment 110 from surface 112. Information and/or commands may be sent through cable 130, traversing center conductor 134 to downhole equipment 110. Information may be sent back to the surface from downhole equipment 110 through extra conductive layer 138. Extra conductive layer 138 may prevent attenuation of signal strength and may allow for information and/or commands to be sent to and from downhole equipment 110 in deeper wells. In contract, cable 130 without conductive layer 138 may require additional downhole devices that may boost signaling currents, which may allow them to travel further downhole. Additionally, signaling currents may attenuate to the point that information may be lost and/or skewed, which may make received information unreliable. Extra conductive layer 138 may comprise copper wound (e.g., copper tape) around insulator 136. Air gaps 142 may prevent components of cable 130 from shearing, deforming, and/or coming out of cable 130 when cable 130 may be bent within a wellbore 116. When bent, air gaps 142 may expand and/or contract, which may allow for components of cable 130 to shift into a void created by air gaps 142. In examples, cable assembly 104 may be permanently disposed within a wellbore and/or removed from wellbore 116 after the used of downhole equipment 110.
A cable assembly may comprise a protective covering and a cable disposed in the protective covering. The cable may comprise a center conductor, an insulator, where the insulator may be disposed about the center conductor, an extra conductive layer, where the extra conductive layer may comprise copper and may be disposed about the insulator. The cable may further comprise an outer conductive casing, wherein the outer conductive casing may be disposed about the conductive layer.
A well system may comprise a cable assembly, which may further comprise a protective covering and a cable. The cable may comprise a center conductor, an insulator, where the insulator may be disposed on the center conductor, an extra conductive layer, where the extra conductive layer may be copper tape and may be disposed on the insulator. The cable may further comprise an outer conductive casing, where the outer conductive casing may be disposed on the conductive layer and a downhole equipment that may be disposed in a wellbore, where the downhole equipment may be connected to the cable assembly.
A method for using a cable assembly in a well may comprise providing the cable assembly, where the cable assembly may comprise a protective covering and a cable, wherein the cable may comprise a center conductor. The cable assembly may further comprise an insulator, where the insulator may be disposed about the center conductor, an extra conductive layer, where the extra conductive layer may comprise copper and may be disposed about the insulator, and an outer conductive casing, where the outer conductive casing may be disposed about the conductive layer. The method may further comprise inserting the cable assembly in the well and sending a signal current through the cable assembly from a surface to a downhole equipment in the well. The cable assembly, well system, and method may include any of the various features of the compositions, methods, and systems disclosed herein, including one or more of the following features in any combination.
The extra conductive layer may further comprises gold, silver, or graphene. The extra conducive layer may be disposed on an inner diameter of the outer conductive casing. The outer conductive casing may comprise incoloy. The extra conductive layer may be in the form of a tape wound around the insulator. The cable assembly may comprise a plurality of cables within the protective covering. A plurality of cable assemblies may be disposed downhole. The cable assembly may be disposed within a tether and the tether may connect a wireline sonde to a hoist. The cable assembly may be used for sending a signal current through a center conductor of the cable from a surface to a downhole equipment in a wellbore. The cable assembly may be used for sending a second signal current from the downhole equipment to the surface through the extra conductive layer of the cable. The cable assembly may be used for sending power from a surface to a downhole equipment through the cable assembly. The extra conductive layer may be in the form of a tape wound around the insulator.
The preceding description provides various embodiments of the systems and methods of use disclosed herein which may contain different method steps and alternative combinations of components. It should be understood that, although individual embodiments may be discussed herein, the present disclosure covers all combinations of the disclosed embodiments, including, without limitation, the different component combinations, method step combinations, and properties of the system.
It should be understood that the compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces.
Therefore, the present embodiments are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual embodiments are discussed, the invention covers all combinations of all those embodiments. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present invention.
Filing Document | Filing Date | Country | Kind |
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PCT/US2016/055568 | 10/5/2016 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2018/067146 | 4/12/2018 | WO | A |
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