Patent Publication Number: US-8993889-B2

Title: Oil smelter cable

Description:
FIELD OF THE INVENTION 
     The present application relates to an oil smelter cable for facilitating the transfer of oil to the surface. 
     BACKGROUND OF THE INVENTION 
     Wells are conventionally used to extract oil to the surface. A conventional oil well generally includes wellbores with electrical submersible pumps and production tubing that transfers the oil to the surface where a wellhead is located. A flowline extends from the wellhead for the transmission of the oil. To facilitate flow of the oil up to the surface, a heater cable that extends through the wellhead and down the well along its tubing is often used. U.S. Pat. No. 5,782,301 to Neuroth et al., the subject matter of which is herein incorporated by reference, discloses a conventional heater cable. 
     The components that make up conventional heater cables are often expensive. Therefore, there is a need for an oil smelter cable that is less expensive than the conventional heater cables. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides an oil smelter cable that comprises a plurality of conductor assemblies. Each conductor assembly includes a galvanized steel conductor, an insulation layer that surrounds the galvanized steel conductor, and a metal sheath that surrounds the insulation layer. An armor layer surrounds the plurality of conductor assemblies. 
     The present invention may also provide an oil smelter cable that consists of a first, second and third conductor assemblies. Each conductor assembly consists of a galvanized steel conductor, an insulation layer that surrounds the galvanized steel conductor, and a metal sheath that surrounds the insulation layer. An armor layer surrounds the first, second, and third conductor assemblies. 
     The present invention yet further provides an oil smelter cable that comprises a plurality of conductor assemblies. Each conductor assembly includes a galvanized steel conductor, a polymer insulation layer that surrounds the galvanized steel conductor, and a lead sheath that surrounds the polymer insulation layer. A galvanized steel tape is wrapped around the plurality of conductor assemblies. 
     Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying  FIG. 1 , which is a cross-sectional view of a cable in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Referring to  FIG. 1 , the present invention provides an oil smelter cable  100  that requires less expensive materials and fewer components than the prior art cables. The cable  100  generally includes a plurality of conductor assemblies  102  that each includes a conductor  110 , an insulation layer  120  surrounding the conductor  110 , and a metal sheath  130  surrounding each insulation layer  120 . No other components, such as braids, are needed. The conductors  110  are preferably stranded conductors. The conductor assemblies  102  are arranged in a substantially parallel or side-by-side relationship to one another and an outer armor  140  surrounds the conductor assemblies  102 . The cable  100  is preferably of a flat type and each conductor assembly  102  has a substantially circular cross-sectional shape. In a preferred embodiment, the cable  100  includes three conductor assemblies  102 . 
     The conductors  110  are made of a suitably high electrical resistivity conduct, preferably galvanized steel. The galvanized steel is significantly less expensive than conventional copper conductors. The electrically insulated conductors  110  are connected to a power source, which preferably supplies three-phase electrical current down conductors  110 . 
     The insulation layer  120  surrounding each conductor  110  is preferably a high temperature tolerant electrical insulation. The insulation layer  120  is preferably formed of Ethylene-Propylene-Diene-Monomer (EPDM). Alternately, the insulation layer  120  may be formed of fluorinated ethylene propylene (FEP), polyterrafluoroethylene (PTFE), or polyvinylidine fluoride (PVDF), Fluoroelastomers, TPOs, and the like. 
     The protective metal sheaths  130  are preferably extruded over each insulation layer  120 . The metal sheaths  130  are preferably made of a material which is a good thermal conductor and provides protection against damage to the electrical insulation layers. For example, the metal sheaths  130  may be formed of lead or a lead alloy. To enhance heat conduction, the metal sheaths  130  may be in physical contact with each other. 
     The armor  140  is a metal tape, preferably formed of galvanized steel, that is wrapped around the conductors  102  in a conventional manner for an electric power cable. The armor  140  is a good heat conductor. Heat conduction is also facilitated by metal-to-metal contact with the metal sheaths  130 . 
     In operation, power is supplied to the conductors  110  of the conductor assemblies  102  and heat is generated within conductors  110  because of high current flow and resistivity of conductors. The heat passes through the insulation layers  120  and into the lead sheaths  130 . The heat transmits readily through the lead sheaths  130  and out to the armor  140 . Oil flowing through tubing of the well is therefore heated by the cable  100 . 
     While a particular embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.