Patent Application
20100074583
The present invention relates generally to a cable component having an optical fiber encased therein, and more particularly to such a cable component having a plurality of shaped profiles which combine to form an enclosure for an optical fiber.
In the oil and gas well industry tools are often lowered in a well by a cable (commonly referred to as a wireline or a wireline cable) for the purpose of monitoring or determining characteristics of the well. Once data is collected by the tool, it is sent from the wellbore to the surface of the well through the cable. Recently, it has been discovered that optical fibers are able to transmit data from a wellbore to the surface of a well at a much faster rate than electrical data transmission lines. As such, it is desirable to include optical fibers in oil and gas well wireline cables for the purpose of data transmission. However, several characteristics of optical fibers make them vulnerable to damage in oilfield operations.
For example, exposure to hydrogen at high temperatures results in a “darkening” of optical fibers, which leads to a reduction in data carrying capacity. The difference in linear stretching of optical fibers as compared to the other components of the cable requires additional fiber length to be built in to the optical fiber components, which complicates the manufacturing process. Volatilization of volatile organic compounds (VOCs) in coatings or other polymeric protective layers on the optical fibers releases additional hydrogen which can attack and darken the fibers. Optical fibers are susceptible to hydrolytic attack in the presence of water. A lack of transverse toughness of optical fiber component construction leads to potential point loading and micro-bending issues, which can lead to mechanical failure of the optical fibers and/or increased data attenuation.
One technique used to protect optical fibers from many of the problems listed above is to encase them in a solid metallic tube. However, encasing an optical fiber in a metallic tube has several disadvantages. For example, encasing an optical fiber in a metallic tube is very expensive. End to end welding of metallic tubes, which is necessary to create a wireline cable of a sufficient length, creates difficult-to-detect pinholes. Such welding also produces welding gases, which if trapped inside the tube can lead to deterioration of the optical fibers inside the tube.
In addition, when subjected to torque (which is present in most wireline cables) solid metallic tubes are prone to collapse unless they are excessively thick, as such the tube must be sufficiently thick to prevent collapse under such torque and/or other loads or pressures. However, such added thickness takes up valuable space within the cable core. Also, solid metallic tubes have limited flexibility, and a low fatigue life in dynamic applications; and optical fibers encased in metallic tubes cannot be spliced without over-sizing them. Accordingly, a need exists for an improved method and/or apparatus for encasing an optical fiber in a cable.
In one embodiment, the present invention is a cable that includes at least one optical fiber; and a plurality of shaped profiles having inner and outer surfaces such that the inner surfaces combine to from an enclosure for the at least one optical fiber.
In another embodiment, the present invention is a cable component that includes at least one optical fiber; a soft polymer layer disposed about an outer surface of the at least one optical fiber; a plurality of electrically conductive shaped profiles having inner and outer surfaces such that the inner surfaces combine to from an enclosure for the at least one optical fiber; and an outer insulation layer formed around the outer surfaces of the plurality of shaped profiles, wherein the soft polymer layer over the fiber at least substantially fills an area between the inner surfaces of the plurality of shaped profiles and the outer surface of the at least one optical fiber.
In yet another embodiment, the present invention is a cable component including at least one optical fiber; a core having at least one peripheral groove that extends substantially along the length of the cable component, wherein the at least one peripheral groove receives the at least one optical fiber; and a protective material disposed in surrounding relation to both the at least one optical fiber and the core.
In yet another embodiment, the present invention is a method of manufacturing a cable component that includes forming a plurality of shaped profiles having inner and outer surfaces such that the inner surfaces combine to from an enclosure; and placing at least one optical fiber in said enclosure.
These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
FIGS. 23A-23AJ show various alternative shapes of the core of the cable component of
As shown in
In one embodiment, the shaped profiles 12 are formed by a cold forming process, such as a drawing process, an extrusion process, a rolling process, or any combination thereof, among other appropriate processes. These shaped profiles 12 may be composed of a conductive material, such as a metallic material, for example stainless steel, copper, steel or copper-clad steel, among other appropriate materials. These materials may be in the form of single or stranded wires. Alternatively, the shaped profiles 12 may be composed of any other appropriate material, such as a polymeric material. The shaped profiles 12 provide hoop strength to the cable component 10A. In addition, in embodiments where the shaped profiles 12 are composed of a conductive material, the shaped profiles 12 can be used as electrical conductors to send electrical signals, to transmit power, and/or to transmit data. This can be done in addition to the optical fiber 16 being used to transmit data/and or power.
Within the enclosure 14 formed by the shaped profiles 12 is the optical fiber 16. The optical fiber 16 may be any appropriate single or multi-mode optical fiber. Commercially available optical fibers 16 typically include an outer coating such as an acrylic coating, or silicon followed by a perfluoroalkoxy resin (PFA) coating. As such, unless otherwise specified, the term optical fiber includes this outer coating.
As shown in
Disposed about the outer surface of the shaped profiles 12 is an outer insulation layer 20. The outer insulation layer 20 holds the shaped profiles 12 together and improves the durability and manufacturability of the cable component 10A. In one embodiment, the shaped profiles 12 are “physically independent.” That is, the shaped profiles 12 are separate parts that are not coupled, joined or bonded together, but instead are merely held together by the outer insulation layer 20.
In one embodiment, the outer insulation layer 20 is composed of a polymer having a reasonably high melting temperature such that it does not melt in the high temperature environments of typical oil and gas wells. For example, the outer insulation layer 20 may be composed of a polymeric material or a hard plastic material, for example polyetheretherketone (PEEK), or another fluoropolymer, for example Tefzel®, a perfluoroalkoxy resin (PFA), a fluorinated ethylene propylene copolymer (FEP), tetrafluoroethylene (TFE), perfluoromethylvinylether copolymer (MFA), or among other appropriate polymers and/or fluoropolymers. The insulation layer 20 may have more than one polymer disposed in such a way as to meet stacked di-electric concepts.
Although not shown, the cable component 10A may further include an outer metallic shell. This outer metallic shell may be an extruded metallic shell composed of lead, or an alloy such as tin-zinc, tin-gold, tin-lead, or tin-silver, among other appropriate materials. The metallic shell may be disposed over the outer insulation layer 20 or between the shaped profiles 12 and the outer insulation layer 20.
In one embodiment, the cable component 10A is manufactured by encasing the optical fiber 16 in an insulation layer 18; and placing multiple shaped profiles 12 around the optical fiber 16 and the insulation layer 18 to form an enclosure 14 around the optical fiber 16 and its insulation layer 18. The outer insulation layer 20, such as a layer of a hard plastic material, is then extruded over the shaped profiles 12 to hold or lock the shaped profiles 12 in place over the optical fiber 16.
In one embodiment, prior to placing the shaped profiles 12 about the optical fiber 16 and its insulation layer 18, the insulation layer 18 is in a liquid form such as an uncured silicone. In such a case, when the shaped profiles 12 are placed about the optical fiber 16 and its insulation layer 18, the liquid insulation layer 18 is allowed to fill the enclosure 14 in the area between the inner surfaces of the shaped profiles 12 and the outer surface of the optical fiber 16. The insulation layer 18 can then be hardened by curing to hold its shape between the shaped profiles 12 and the optical fiber 16.
In one embodiment, the wrapped wire 24 is composed of a conductive material, such as a metal for example copper, copper-clad steel, or steel, among other appropriate materials. Alternatively, the wrapped wire 24 may be composed of any other appropriate material, such as a polymeric material or a twisted yarn. However, in embodiments where the wrapped wire 24 is composed of a conductive material, the wrapped wire 24 serves to minimize thermal expansion along the longitudinal axis of the cable component 10C and may serve as an electrical conductor capable of sending electrical signals, to transmitting power, and/or transmitting data. As with the cable component 10B of
Although each of the above cable components 10A-10C includes only one optical fiber 16, any of the cable components according to the present invention, including those described both above and below, may include any appropriate number of optical fibers 16. For example,
For example, in one embodiment prior to placing the shaped profiles 12 about the optical fibers 16D and their insulation layer 18D, the insulation layer 18D is in a liquid form such as an uncured silicone. In such a case, when the shaped profiles 12 are placed about the optical fibers 16D and their insulation layer 18D, the liquid insulation layer 18D is allowed to fill the enclosure 14 in the area between the inner surfaces of the shaped profiles 12 and the outer surface of the optical fibers 16D. The insulation layer 18D can then be hardened by curing to hold its shape between the shaped profiles 12 and the optical fibers 16D. In this way, the insulation layer 18D occupies the entire space between the inner surfaces of the shaped profiles 12 and the outer surface of the optical fibers 16D. In all other respects the cable component 10D of
In each of the above described cable components 10A-10D, the shaped profiles 12 include two semi-circular shaped profiles which together form a hollow cylinder, with a circular shaped enclosure 14 for receiving one or more optical fibers 16.
For example, in the depicted embodiment, the shaped profiles 12F include eight arched pie-shaped profiles 12F. However, in other embodiments any appropriate number of arched pie-shaped profiles 12F may be used, the advantage being the greater the number of shaped profiles 12F, the greater the compression resistance and the greater the flexibility of the cable component 10F. In all other respects the cable component 10F of
In this embodiment, the insulation layer 18G around the optical fiber 16 is circular adjacent to the optical fiber 16 and polygonal adjacent to the inner surfaces of the keystone shaped profiles 12G. This can be achieved by any appropriate method, such as the above described method of filling the area between the inner surfaces of the shaped profiles 12G and the outer surface of the optical fiber 16 with a liquid insulator and curing the insulator in place.
In one embodiment, after the keystone shaped profiles 12G are placed around the optical fiber 16 and its insulation layer 18G (and the insulation layer 18G is cured if that method is used), an outer insulation layer 20G, such as a polymeric layer, is compression extruded over the shaped profiles 12G to hold the shaped profiles 12G in place and to create a circular outer profile for the cable component 10G.
In the depicted embodiment, the shaped profiles 12G include six keystone shaped profiles 12G. However, in other embodiments any appropriate number of keystone shaped profiles 12G may be used. Such keystone shaped profiles 12G produce a cable component 10G that is much more flexible and compression resistant that a cable component having an optical fiber encased in a solid metallic tube. In all other respects, the cable component 10G of
In this embodiment, the insulation layer 18H may conform to the area between the inner surface of the shaped profiles 12H and the optical fiber 16 by any appropriate method, such as any of those described above. In addition, the outer insulation layer 20H may conform to the outer surface of the shaped profiles 12H and form a circular outer profile for the cable component 10H by any of the methods described above.
In the depicted embodiment, the shaped profiles 12H include eight triangular shaped profiles 12H. However, in other embodiments any appropriate number of triangular shaped profiles 12H may be used. Such triangular shaped profiles 12H produce a cable component 10H that is much more flexible and compression resistant than a cable component having an optical fiber encased in a solid metallic tube. In all other respects the cable component 10H of
In this embodiment, the insulation layer 18I may conform to the area between the inner surface of the rectangular shaped profiles 12I and the optical fiber 16 by any appropriate method, such as any of those described above. In addition, the outer insulation layer 20I may conform to the outer surface of the rectangular shaped profiles 12I and form a circular outer profile for the cable component 10I by any of the methods described above.
In the depicted embodiment, the shaped profiles 12I include eight rectangular shaped profiles 12I. However in other embodiments any appropriate number of rectangular shaped profiles 12I may be used. Such rectangular shaped profiles 12I produce a cable component 10I that is much more flexible and compression resistant than that of a cable component having an optical fiber encased in a solid metallic tube. In all other respects the cable component 10I of
The embodiment of
The embodiment of
The embodiment of
Note that any of the cable components 10A-10J in any of the embodiments described above with respect to
Each groove 40 in the core 38 receives an optical fiber 16, which is surrounded by a insulation layer 18N. Although three grooves 40, each with one optical fiber 16 disposed therein, are shown. The core 38 may include any appropriate number of grooves 40, and each groove 40 may contain any appropriate number of optical fibers 16 disposed therein.
The optical fiber 16 and the insulation layer 18N may be any of those describe above with respect to
In either method, portions of the insulator 18N that extend past the outer surface of the non-grooved portions of the cable component 10N are removed, as shown in
As shown in
In either event, as shown in
FIGS. 23A-23AJ shows a variety of core shapes 38A-38AJ that may be used in any of the embodiments of the cable component 10N as described with respect to
The cable components in each of the embodiments described above may provide one or more advantages over cable components which incorporate optical fibers encased in a solid metal tube including: decreased expense, increased manufacturability, increased compression resistance, increased crush resistant, smaller cross sectional area, able to completely seal the encased optical fiber(s), able to be sliced while maintaining a relatively small cross sectional area, and increased flexibility.
In addition, any of the cable components 10 may be replaced by an insulated conductor that does not include an optical fiber, such as an insulated copper wire. Such an insulated conductor may be used to send electrical signals, to transmit power, and/or to transmit data.
In one embodiment, the cable 100 is suitable for use in oil exploration such as a seismic cable, a wireline cable, a slickline cable, or a multi-line cable, amount other suitable cables. In the depicted embodiment, the cable components 10 are encased in a first insulation or jacket layer 120 and a second insulation or jacket layer 120′. Sandwiched between the insulation layers is a reinforcement layer 102. The reinforcement layer 102 may be composed of any material appropriate for adding strength to the cable, such as a metallic wire, which may be helically wrapped around the first insulation layer 120.
The first and second insulation layers 120,120′ may be composed of any of the material described above with respect to the outer insulation layer 20 described in
Cables according to the invention may be used with wellbore devices to perform operations in wellbores, penetrating geologic formations that may contain gas and oil reserves. The cables may be used to interconnect well logging tools, such as gamma-ray emitters/receivers, caliper devices, resistivity measuring devices, seismic devices, neutron emitters/receivers, and the like, to one or more power supplies and data logging equipment outside the well. Cables of the invention may also be used in seismic operations, including subsea and subterranean seismic operations, the cables may also be useful as permanent monitoring cables for wellbores.
The preceding description has been presented with reference to presently preferred embodiments of the invention. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, and scope of this invention. Accordingly, 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.
This application claims priority to and is a Divisional of co-pending U.S. patent application Ser. No. 11/461,943, filed on Aug. 2, 2006, which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11461943 | Aug 2006 | US |
| Child | 12623059 | US |
