Patent Application
20250215756
The present disclosure relates generally to wellbore operations and, more particularly (although not necessarily exclusively), to a tubing encapsulated conductor with a low-resistance encapsulation layer for supplying power to electrical equipment used in wellbore operations.
A wellbore can be formed in a subterranean formation for extracting produced hydrocarbon or other suitable material or injecting water or other suitable or desirable fluids. Wellbore operations can be performed to extract the produced hydrocarbon material, and may include deployment, completion, and production operations. As part of performing a deployment operation, electrical equipment, such as a sensors, valves, and pumps, may be deployed downhole in the wellbore. Power can be supplied to the electrical equipment during deployment via a control line, such as a Tubing Encapsulated Conductor (TEC). The TEC can be encapsulated by a plastic-like polymer suitable for well conditions. The plastic-like polymer can provide electrical insulation on an outer surface of the TEC. Due to the insulation, both a positive electrical path (e.g., from a power source) and a ground-side electrical path (e.g., returning to the power source from a downhole load) must flow through the TEC during deployment operations. In particular, the positive electrical path can flow from the power source to the electrical equipment via conductors of the TEC, and the ground-side electrical path can flow back to the power source through a metal sheath of the TEC. The metal sheath can exhibit significant electrical resistance causing power requirements for powering the electrical equipment via the TEC to be high during deployment operations. Thus, using the metal sheath as a ground path to the surface may limit or prohibit essential functions of the electrical equipment.
Additionally, after deployment operations, the TEC can be connected to a production tubing hanger, at which point the ground-side electrical path can flow through the production tubing hanger, downhole tubing, or a combination thereof, providing a ground path through the wellbore equipment rather than the metal sheath. The production tubing hanger and the downhole tubing can exhibit significantly less electrical resistance than the metal sheath. Therefore, during well preparations, deployment of the electrical equipment, system integration tests, deck testing, etc. return path resistance through the TEC sheath can become high enough that the voltage left to operate the downhole equipment is insufficient to allow operation of the downhole equipment. This can result in inefficient or inconsistent functioning of the electrical equipment and can limit types of electrical equipment that can be used during wellbore operations.
Certain aspects and examples of the present disclosure relate to a Tubing Encapsulated Conductor (TEC) with a low-resistance ground usable to supply power to downhole electrical equipment used in wellbore operations. The TEC can be a type of electrical control line that includes one or more conductors surrounded by a protective tubing or sheath. In particular, the one or more conductors can be wires made of copper, aluminum, or other suitable materials. Each of the one or more conductors can be surrounded by an insulated tubing for electrical and mechanical protection and isolation. Then a filler material, such as epoxy resin, polyurethane, silicone, polypropylene, polyolefin, fluorinated ethylene propylene (FEP), etc., can be used to fill voids between the one or more conductors and a metal sheath. The filler material can provide mechanical stability and can prevent movement or deformation of the one or more conductors within the TEC. The metal sheath can be another protective barrier that encompasses the one or more conductors and the filler. In particular, the metal sheath can act as a pressure barrier for the one or more conductors and can be compatible with a downhole environment of the wellbore. Additionally, an encapsulation layer with an embedded conductive wire can make up an outermost layer of the TEC. The encapsulation layer can be made of a polymer and can provide some flexibility or deformation for the TEC and shield the metal sheath against abrasion, chemicals, moisture, or other environmental factors of the wellbore. In applying the encapsulation layer to the TEC, the embedded conductive wire may be positioned such that it is encapsulated by the encapsulation layer and in such a way to make direct contact with the metal sheath for at least a portion of the length of the TEC. The encapsulation layer can also act as a buffer between the metal sheath and a tubing or casing positioned in the wellbore to dampen vibrations or prevent other suitable undesirable interactions between the metal sheath and tubing or casing.
The embedded conductive wire can provide a direct conductive path between the metal sheath and a surface of the well. As a result, a ground-side electrical path can is established from a downhole location of the metal sheath to the surface of the well. Due to the embedded conductive wire providing a lower electrical resistance than the metal sheath, the embedded conductive wire embedded in the encapsulation layer can reduce electrical resistance associated with grounding the TEC during testing and deployment operations. In this way, functioning of the electrical equipment can be improved and a variety of electrical equipment can be implemented, functioned, and tested downhole.
Illustrative examples are given to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects, but, like the illustrative aspects, should not be used to limit the present disclosure.
The well system 100 has the production tubing system 102, which generally utilizes a production tubing string 118, e.g., to conduct various deployment, drilling, and production operations. As used herein, the term “production tubing string” can include any pipe string that may be deployed in a wellbore 122 including continuous or jointed metal tubulars such as low-alloy carbon-steel tubulars, composite tubulars, capillary tubulars and the like. Additionally, although a production tubing system 102 with production tubing string 118 is depicted, the well system 100 can include any type of tubing. For example, completion tubing may be used in place of the production tubing string 118.
The production tubing string 118 can include an inner annulus or flow bore 119 extending along a length of the tubing string 118. The production tubing system 102 may also include a power source 104 and a command station 106 for controlling wellbore operations. Thus, the production tubing system 102 may be used in this example for servicing a pipe system 128. For purposes of this disclosure, the pipe system 128 may include casing, risers, tubing, drill strings, completion or production strings, subs, heads or any other pipes, tubes or equipment that couples or attaches to the foregoing, such as collars, cleaning tools, and joints, as well as the wellbore 122 itself and laterals in which the pipes, casing and strings may be deployed. In this regard, the pipe system 128 may include one or more casing strings, which may be cemented in wellbore 122. An annulus 132 is formed between the walls of sets of adjacent tubular components, such as concentric casing strings or the exterior of production tubing string 118 and an inside wall of wellbore 122.
A permanent downhole gauge carrier 134 or a series of permanent downhole gauge carriers may be coupled to a downhole end of the production tubing string 118. Disposed downhole of the permanent downhole gauge carrier(s) 134 may be electrical equipment 138, which may include motors, valves, etc. A tubing encapsulated conductor (TEC) 140 can run from a drum 120 located at a surface 116, proximate to the production tubing string 118, and may be electrically coupled to the permanent downhole gauge carrier 134. The TEC 140 may include electrical conductors and may operably couple the permanent downhole gauge carrier 134 to the command station 106. Thus, the TEC 140 may be used as a conduit for electric power.
In an example, the conductors can be one or more interior wires, which can transmit electric power from the power source 104 to the permanent downhole gauge carrier 134, the electrical equipment 138, or a combination thereof. The TEC 140 can further include a metal sheath positioned around the one or more interior wires to act as a pressure barrier. Additionally, the outermost layer of the TEC 140 can be an encapsulation layer. In some examples, cross coupling clamps 108a-b may be used for coupling the TEC 140 to the production tubing string 118.
The TEC 140 can include an interior wire 210 made of a conducting material such as copper, copper alloy, or aluminum. The interior wire 210 can be the central component of the TEC 140, which carries electrical current. The TEC 140 can also include an insulated tubing 208 which can surround the interior wire 210 to provide electrical insulation and protection for the interior wire 210. The insulated tubing 208 can be made of any suitable insulating material including but not limited to polyethylene, polypropylene, FEP, or epoxy resins. The TEC 140 can further include a metal sheath 204, which can further protect the interior wire 210 by providing a pressure barrier between the interior wire and a wellbore environment. The metal sheath 204 may be made of nickel, aluminum, steel, or alloys thereof or of other suitable materials. Additionally, a filling material 206, such as epoxy resin, polyurethane, or polypropylene can fill a void between the insulated tubing 208 and the metal sheath 204 to maintain a position of the interior wire 210 within the TEC 140.
The TEC 140 can further include one or more encapsulation layers 212, which can be an outermost layer of the TEC 140. The encapsulation layer 212 can provide vibration dampening and enable some deformation of the TEC 140. The conductive ground wire 202 may be added to the TEC 140 during the encapsulation process with the encapsulation layer 212. For example, as the conductive ground wire 202 may be positioned adjacent to the sheath 204 while the encapsulation layer 212 is extruded onto the sheath 204. The extrusion of the encapsulation layer 212 may be performed in such a manner that the conductive ground wire 202 is in physical contact with the sheath 204 along a length of at least a portion of the TEC 140. In some examples, the conductive ground wire 202 may be in continuous contact or substantially continuous contact with the sheath 204 upon encapsulation by the encapsulation layer 212. As used herein, the term “substantially continuous” indicates that the conductive ground wire 202 maintains contact with the sheath 204 for at least 80% of the length of the TEC 140. In additional examples, the conductive ground wire 202 may only make contact periodically with the sheath 204 along the length of the TEC 140. Further, while
The conductive ground wire 202 may include any type of conductive wire capable of reducing the resistance provided by the sheath 204 when the sheath 204 is used as the ground path for powering the downhole electrical equipment 138. In some examples, the conductive ground wire 202 may be a 14-gauge to 20-gauge copper wire. Other materials and gauges may also be used. Additionally, the conductive ground wire 202 only needs to maintain its function during a deployment operation of the TEC 140, as once deployment of the completion is concluded, the grounding function may be provided by the completion tubing. For example, the conductive ground wire 202 may be selected with a gauge that would likely fail over the life the well. That is, to save costs associated with the conductive ground wire 202, a smaller gauge may be selected that may stop being functional after a relatively short period of time.
During a wellbore operation, such as a deployment operation, electrical equipment can be deployed downhole in the wellbore. The TEC 140 can electrically couple a power source associated with the wellbore and electrical equipment located downhole within the wellbore during deployment. The power source can be a generator or other suitable power source positioned at a surface of the wellbore. The electrical equipment can be tubing conveyed electrically operated completions equipment or other suitable downhole electrical equipment. Examples of the electrical equipment can include pumps, downhole monitoring tools, or other suitable equipment.
The TEC 140 can include one or more interior wires for transmitting electric power from the power source to the downhole electrical equipment. The TEC 140 can also include a conductive ground wire within the encapsulation layer 212 of the TEC 140 and in contact with the metal sheath. The metal sheath can combine with the conductive ground wire to act as a ground for a circuit that includes the power source, the TEC 140, and the electrical equipment. Because the metal sheath can be characterized by high electrical resistance, which can increase power requirements for supplying power to the electrical equipment via the TEC 140, the conductive ground wire may reduce the resistance on the ground path of the circuit. Thus, a positive electrical path can flow from the power source to the electrical equipment via the one or more interior wires of the TEC 140. Then, a ground-side electrical path can enable current flow from the electrical equipment, through the metal sheath and the conductive ground wire, and to the power source. The electrical resistance of the metal sheath can be greater than the conductive ground wire. Therefore, by electrically coupling the metal sheath and the conductive ground wire within the encapsulation layer 212, the electrical resistance can be reduced, and the electrical equipment can be powered more efficiently during run-in operations of the electrical equipment.
At block 402, the process 400 involves electrically coupling a low-resistance TEC 140 between a power source 104 associated with a wellbore 122 and at least one piece of electrical equipment 138 used downhole within the wellbore 122 during a wellbore operation performed with respect to the wellbore 122. The wellbore operation can be a deployment operation in which the electrical equipment 138 is being deployed into the wellbore 122. The power source 104 can be at a surface of the wellbore 122 and may include a generator, connection to an electrical grid, or another suitable power source. The electrical equipment 138 can include sensors, valves, pumps, or other suitable electrically operated downhole equipment used for wellbore operations.
At block 404, the process 400 involves supplying power to the at least one piece of electrical equipment 138 during the wellbore operation via the low-resistance TEC 140. Current can be transmitted from the power source 104 to the electrical equipment 138 via at least one interior wire of the tubing encapsulated conductor 140. The current can further return to the power source 104 via the conductive ground wire 202 that is in contact with the metal sheath 204 within the encapsulation layer 212 of the TEC 140.
For the current to return via the ground wire 202, the ground wire 202 can be electrically coupled to the metal sheath 204 of the TEC 140 using the encapsulation layer of the TEC 140. For example, the ground wire 202 can be in contact with the metal sheath 204 at one or more locations. The current can be transmitted from the electrical equipment 138 to the metal sheath 204 of the TEC 140. Then, at the locations where the metal sheath 204 is in contact with the ground wire 202, current can flow across the ground path provided by the ground wire 202. In this way, the ground wire 202 can act as a low-resistance ground for the TEC 140 during the deployment operation.
In some aspects, systems, methods, or tubing encapsulated conductors for supplying power to downhole equipment are provided according to one or more of the following examples:
As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”).
Example 1 is a system comprising: a tubing positionable downhole in a wellbore; a tubing encapsulated conductor, wherein at least a portion of the tubing encapsulated conductor is positionable downhole in the wellbore, the tubing encapsulated conductor comprising: at least one interior wire positionable to transmit electric power from a power source associated with the wellbore to at least one piece of electrical equipment during a wellbore operation performed with respect to the wellbore, the at least one piece of electrical equipment positionable downhole in the wellbore; a metal sheath positionable around the at least one interior wire; a ground wire positionable external to the metal sheath; and an encapsulation layer positionable to encoat the metal sheath and the ground wire to facilitate one or more electrical couplings between the metal sheath and the ground wire.
Examples 2 is the system of example 1, wherein the ground wire comprises a copper wire comprising a 14 gauge to a 20 gauge thickness.
Example 3 is the system of example(s) 1-2, wherein the encapsulation layer is positionable to maintain the metal sheath in contact with the ground wire at a plurality of locations along a length of the metal sheath.
Example 4 is the system of example(s) 1-3, wherein the tubing encapsulated conductor further comprises at least one insulated tubing positionable around each of the at least one interior wire to provide electrical and mechanical isolation for the at least one interior wire.
Example 5 is the system of example(s) 1-4, wherein the tubing encapsulated conductor further comprises a filling material positionable between the at least one interior wire and the metal sheath to maintain a position of the at least one interior wire within the tubing encapsulated conductor.
Example 6 is the system of example(s) 1-5, wherein the wellbore operation is a tubing deployment operation.
Example 7 is the system of example(s) 1-6, wherein the encapsulation layer is extrudable on the metal sheath and the ground wire to maintain the electrical coupling between the metal sheath and the ground wire.
Example 8 is a tubing encapsulated conductor comprising: at least one interior wire positionable to transmit electric power from a power source associated with a wellbore to at least one piece of electrical equipment during a wellbore operation performed with respect to the wellbore, the at least one piece of electrical equipment positionable downhole in the wellbore; a metal sheath positionable around the at least one interior wire; a ground wire positionable external to the metal sheath; and an encapsulation layer positionable to encoat the metal sheath and the ground wire to facilitate one or more electrical couplings between the metal sheath and the ground wire.
Example 9 is the tubing encapsulated conductor of example 8, wherein the metal sheath and the ground wire are in electrical communication with one another to provide a ground path to the power source.
Example 10 is the tubing encapsulated conductor of example(s) 8-9, The tubing encapsulated conductor of claim 8, wherein the ground wire comprises a copper wire comprising a 14 gauge to a 20 gauge thickness.
Example 11 is the tubing encapsulated conductor of example(s) 8-10, wherein the encapsulation layer is positionable to maintain the metal sheath in contact with the ground wire at a plurality of locations along a length of the metal sheath.
Example 12 is the tubing encapsulated conductor of example(s) 8-11, wherein the tubing encapsulated conductor further comprises at least one insulated tubing positionable around each of the at least one interior wire to provide electrical and mechanical isolation for the at least one interior wire.
Example 13 is the tubing encapsulated conductor of example(s) 8-12, wherein the wellbore operation is a tubing deployment operation.
Example 14 is the tubing encapsulated conductor of example(s) 8-13, wherein the encapsulation layer is extrudable on the metal sheath and the ground wire to maintain the electrical coupling between the metal sheath and the ground wire.
Example 15 is a method comprising: electrically coupling a tubing encapsulated conductor between a power source associated with a wellbore and at least one piece of electrical equipment used downhole within the wellbore during a wellbore operation performed with respect to the wellbore; and controlling a supply of power to the at least one piece of electrical equipment during the wellbore operation via the tubing encapsulated conductor, wherein current is transmitted from the power source to the at least one piece of electrical equipment via at least one interior wire of the tubing encapsulated conductor, and wherein the current returns to the power source via a metal sheath of the tubing encapsulated conductor and a ground wire positioned between an encapsulation layer and the metal sheath of the tubing encapsulated conductor.
Example 16 is the method of example 15, wherein the metal sheath and the ground wire are in electrical communication with one another to provide a ground path to the power source.
Example 17 is the method of example(s) 15-16, wherein the ground wire comprises a copper wire comprising a 14 gauge to a 20 gauge thickness.
Example 18 is the method of example(s) 15-17, wherein the tubing encapsulated conductor further comprises at least one insulated tubing positioned around each of the at least one interior wire to provide electrical and mechanical protection for the at least one interior wire.
Example 19 is the method of examples 15-18, wherein the tubing encapsulated conductor further comprises a filling material positioned between the at least one interior wire and the metal sheath to maintain a position of the at least one interior wire within the tubing encapsulated conductor.
Example 20 is the method of examples 15-19, wherein the wellbore operation is a tubing deployment operation.
The foregoing description of certain examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure.
