Exploring, drilling and completing hydrocarbon and other wells are generally complicated, time consuming, and ultimately very expensive endeavors. In recognition of these expenses, added emphasis has been placed on efficiencies associated with well completions and maintenance over the life of the well. So, for example, enhancing efficiencies in terms of logging, perforating or any number of interventional applications may be of significant benefit, particularly as well depth and complexity continues to increase.
One manner of conveying downhole tools into the well for sake of logging, perforating, or a variety of other interventional applications is to utilize slickline. A slickline is a low profile line or cable of generally limited functionality that is primarily utilized to securely drop the tool or toolstring vertically into the well. However, with an increased focus on efficiency, a slickline may be provided with a measure of power delivering or telemetric capacity. This way, a degree of real-time intelligence and power may be available for running an efficient and effective application. That is, instead of relying on a downhole battery of limited power, a manner of controllably providing power to the tool from oilfield surface equipment is available as is real-time communications between the tool and the surface equipment.
As with a less sophisticated slickline lacking power and communications, a metal wire may be utilized in a slickline equipped with power and communications. However, in the latter case, the metal wire may be configured to relay charge. Thus, in order to ensure functionality and effectiveness of the wire it may be jacketed with a polymer to insulate and prevent exposure of the wire to the environment of the well.
Of course, in order to remain effective, a jacket material may be utilized that is configured to withstand the rigors of a downhole well environment. Along these lines, a jacket material is also utilized that is intended to bond well with the underlying slickline wire. Unfortunately however, inherent challenges exist in adhering a polymer jacket material onto a metal wire. As a result, a loose point, crack or other defect at the interface of the jacket and wire may propagate as the slickline is put to use. For example, an unbonded area at the jacket and wire interface may spread as the slickline is randomly spooled from or onto a drum at the oilfield surface. If not detected ahead of time by the operator, this may lead to a failure in the jacket during use in a downhole application. Depending on the application at hand, this may translate into several hours of lost time and expense followed by a repeated attempt at performing the application.
Efforts have been undertaken to improve the bonding between the polymer jacket and underlying wire. For example, the wire may be heated by several hundred degrees ° F. before compression extruding the polymer onto the wire. In theory, a tight molded delivery of the polymer to the wire may be achieved in this way with improved bonding between the wire and the polymer.
Unfortunately, this type of heated compression extruding presents numerous drawbacks. For example, the bonding between the wire and the polymer jacket material may not always be improved. In fact, due to the different rates of cooling, with the jacket material cooling more slowly than the metal wire, the wire may shrink away from the jacket material and allow air pockets to develop at the interface between the wire and forming jacket. This not only results in a failure of adherence at the location of the air pocket but this is a defect which may propagate and/or become more prone to damage during use of the slickline. Once more, heating the wire in this manner may also reduce its strength and render it less capable in terms of physically delivering itself and heavy tools to significant well depths for a downhole application.
On a related note, extruding of the polymer jacket material as noted above is achieved by tightly and compressibly delivering the material onto the wire. That is, a markedly tight stress is imparted on the wire as the material is delivered. Again, in theory this may promote adherence between the polymer and the underlying wire. Unfortunately, while this may initially be true, compression extruding in this manner may smooth the surface of the wire as the polymer material is delivered. Thus, a long term grip on the wire by the material may be adversely affected due to the increased underlying smoothness of the wire.
Ultimately, to a large degree, efforts which have been undertaken to enhance the bond between the polymer jacket and the underlying wire have been counterproductive. Thus, challenges remain in terms of reliably utilizing a slickline with power and telemetric capacity built thereinto.
A method of manufacturing a jacketed metal line is detailed herein. A metal core may be provided with a roughened surface followed by the application of a jacket polymer thereto by way of a non-compression delivery technique, such as tubing extrusion or the like. Subsequently, the jacketed core may be heated. Thus, shaping rollers may subsequently be utilized to shape the jacket about the underlying core. The shaping roller may also remove any trapped air in the jacket and improve the adhesion of the jacket to the wire surface.
Embodiments are described with reference to certain manufacturing techniques that are applicable to polymer jacketed metal lines. The disclosed embodiments herein focus on polymer jacketed slickline. However, such techniques may also be utilized in the manufacture of jacketed metallic tubes, cladded lines, wire rope, armored cable, coiled tubing, casing, monitoring cables and a variety of other metal line types to be jacketed. As used herein, the term “slickline” is meant to refer to an application that is run over a conveyance line that is substantially below 0.25-0.5 inches in overall outer diameter. However, as indicated, other, potentially larger lines may benefit from the techniques detailed herein. Additionally, the embodiments detailed herein are described with reference to downhole applications, such as logging applications, run over slickline. However, other types of downhole applications and line types may take advantage of jacketed lines manufactured according to techniques detailed herein such as, but not limited to downhole applications such as sampling, fishing, clean-out, setting, stimulation, logging, perforating, mechanical services and a variety of other downhole applications. So long as a non-compression technique such as tubing extrusion is utilized to deliver a polymer to a roughened metal core followed by heating and rolling, appreciable benefit may be realized in the reliability and durability of the line for downhole applications.
Referring specifically now to
Regardless of the particular configuration, as shown in
Unlike compression extrusion, the tubing extrusion process 120 allows for more of a loose transition or tapered interfacing 150 as the polymer 155 is brought about the core 110. Thus, in contrast to compression extruding, this would appear to provide less of a grip by the polymer onto the surface of the core 110. That is, a forcible mode of direct compression is not immediately imparted as the polymer 155 is placed about the core 110. However, this also means that as the polymer 155 is added to the core 110, the polymer 155 is added without measurably affecting the roughened surface of the core 110.
With the roughened surface of the core 110 preserved and a thin layer of polymer 155 thereover, the grip between the core 110 and this initial polymer layer 155 may subsequently be enhanced. Specifically, as shown in
The particular polymer utilized may be determined based on the particular use for the jacketed line. For example, in the embodiment of
For example, where higher strength and temperature resistance is sought, the polymer 155 may be a polyetheretherketone (PEEK) (which may comprise one or more members of the polyetheretherketone family) or similarly pure or amended polymer. These may include a carbon fiber reinforced PEEK short-fiberfilled PolyEtherEtherKetone (SFF-PEEK), polyether ketone, and polyketone, polyaryletherketone. Where resistance to chemical degradation or decomposition (such as a reaction between the polymer 155 and a wellbore fluid) is of most primary concern, the polymer 155 may be a fluoropolymer. Suitable fluoropolymers may include ethylene tetrafluoroethylene, ethylene-fluorinated ethylene propylene and perfluoroalkoxy polymer or any member of the fluoropolymer family. Where a less engineered and more cost-effective material choice is viable, the polymer 155 may be a polyolefin such as high density polyethylene, low density polyethylene, ethylene tetrafluoroethylene or a copolymer thereof or any member of the polyolefin family. Such PEEK, fluoropolymer and polyolefin materials may be available with or without a reinforcing additive such as graphite, carbon, glass, aramid or micron-sized polytetrafluoroethylene.
Of course, a variety of different bonding facilitating polymer additives may be incorporated into the polymer 155 as well. These may include modified polyolefins, modified TPX (a 4-methylpentene-1 based, crystalline polyolefin) or modified fluoropolymers with adhesion promoters incorporated thereinto. These promoters may include unsaturated anhydrides, carboxylic acid, acrylic acid and/or silanes. In the case of modified fluoropolymers in particular, adhesion promoters may also include perfluoropolymer, perfluoroalkoxy polymer, fluoroinated ethylene propylene, ethylene tetrafluoroethylene, and ethylene-fluorinated ethylene propylene. In an embodiment, the bonding facilitating polymer additives noted above may comprise a separate layer, or tie layer, extruded or otherwise placed over the polymer 155. The tie layer may comprise any material that enables and/or promotes bonding between the polymer, such as the polymer 155, and a metal substrate, such as the core 110, and/or enables and/or promotes bonding between layers of polymers.
As indicated above, the polymer 155 is provided to a metal core 110 with a roughened outer surface. Thus, referring now to
With specific reference to
With specific reference to
With particular reference to
In a similar embodiment, an initial jacketing with the polymer 155 as detailed above may take place in the form of a charged powder coating. That is, the core 201 is charged as depicted in
Referring now to
Specifically, as shown in
In one or more embodiments, the slickline can be made by placing an initial polymer layer of SFF-PEEK about a metallic component, and placing a second layer of virgin PEEK about the SFF-PEEK. The SFF-PEEK may contain short fiber filler material. The short fiber material may comprise from 0.5% to 30% of the total volume of the SFF-PEEK. The fiber used may be Carbon, glass, an inorganic fiber or filler, or any other suitable material with a low coefficient of thermal expansion. For example, a single-strand wire that comprises the center of a conductor can have a layer of SFF-PEEK extruded thereabout. The SFF-PEEK can be heated and slightly melt the SFF-PEEK, and a virgin PEEK can be extruded about the SFF-PEEK.
In another embodiment, the slickline can be made by placing SFF-PEEK about a metallic component, and then placing a fluoropolymer/PEEK alloy (Doped PEEK) about the SFF-PEEK, forming a bonded fluoropolymer outer jacket. The Doped PEEK can contain fluoropolymer particles in a matrix of PEEK. The fluoropolymer particles can rise as the material cools to form a bonded fluoropolymer outer skin. For example, a single-strand wire that comprises the center of a conductor can have a layer of SFF-PEEK extruded thereabout. The SFF-PEEK can be heated and slightly melt the SFF-PEEK, and a layer of Doped PEEK can be extruded about the SFF-PEEK. As the Doped PEEK cools, fluoropolymer particles in the Doped PEEK can diffuse to the surface to form an impervious fluoropolymer layer.
In an embodiment, the slickline can be made by placing SFF-PEEK about a metallic component, then placing a fluoropolymer/PEEK alloy (Doped PEEK) about the SFF-PEEK, forming a bonded fluoropolymer outer jacket. An additional layer of pure fluoropolymer, forming a final bonded jacket of pure fluoropolymer. For example, a single-strand wire that comprises the center of a conductor can have a layer of SFF-PEEK extruded thereabout. The SFF-PEEK can be heated and slightly melt the SFF-PEEK, and a layer of Doped PEEK can be extruded about the SFF-PEEK. As the Doped PEEK cures, fluoropolymer particles in the Doped PEEK can diffuse to the surface to form an impervious fluoropolymer skin over the Doped PEEK. The fluoropolymer skin of the Doped PEEK layer can be heated to slightly soften the fluoropolymer skin, and a layer of Virgin Fluoropolymer can be extruded about the outer fluoropolymer skin.
Referring now to
In order to run such a real-time downhole application as described above, the slickline 390 is manufactured in a manner that enhances bonding between jacketing polymer material (e.g. 155, 355) and an underlying metallic core (e.g. 110, 200, 201) as shown in
The improved durability of the slickline 390 may also be of benefit even before accessing the well 480. For example, as shown in
Referring now to
With a thin initial layer of polymer jacket now adhered to the underlying metal core, the bonding may be enhanced by application of heat and shaping rollers as indicated at 560 and 575. Thus, the manner by which the initial polymer jacket is provided does not materially affect the outer surface of the core and/or its bonding capacity relative this first jacket layer.
In some embodiments, processing may be stopped with this initially jacketed core. For example, sufficient insulating and protection may be provided via the initial jacket alone or, in some circumstances, initially jacketed cores may be made and stored as is for later processing and completion according to tailored specifications. Regardless, as indicated at 590, additional jacketing by way of compression extrusion, may take place to bring the slickline up to the full intended profile.
In circumstances where the initially jacketed core had been stored for a period prior to addition of the outer jacket, heat is applied before running the line through such compression extrusion. Additionally, in certain embodiments, addition of the initial jacket or later jacketing may be followed by active or controlled cooling so as to minimize the degree to which the metal core and jacketing materials cool at differing rates. Controlled cooling comprises cooling the jacket and/or jacketing slowly in a controlled manner or environment in order to promote the continuation of the bonding between the various materials. For example, the initially jacketed core may be run through or otherwise exposed to a coolant or conventional heat removal system/refrigeration. Thus, defects from such cooling rate disparity may be reduced.
Referring now to
Continuing with reference to
Embodiments detailed hereinabove include techniques for enhancing bonding between a metal core and a polymer jacketing placed thereover. This is achieved in manners that may provide jacketing while avoiding material changes to the surface of the metal core. Thus, subsequent heat and/or shaping rollers may be used to increase the grip between the polymer and metal. Once more, once this initial polymer grip is established, additional polymer jacketing may take place with polymer to polymer adherence assured. As such, a line may be provided that is of improved long term reliability in terms of power and telemetry due to the enhanced bonding of the insulating jacket about the metal core.
A first tie layer 710 can be located between the initial polymer layer 155 and the metal core 110. A second tie layer 720 can be located between the initial polymer layer 155 and the additional polymer layer 601.
The preceding description has been presented with reference to presently preferred embodiments. Persons skilled in the art and technology to which these embodiments pertain will appreciate that alterations and changes in the described structures and methods of operation may be practiced without meaningfully departing from the principle, and scope of these embodiments. For example, while techniques utilized are directed at jacketing a metal core for an oilfield conveyance or line, these techniques may be modified and applied to other hardware such as metallic tool housings. Regardless, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope.
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Number | Date | Country | |
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20160293298 A1 | Oct 2016 | US |