Heater cable and method for manufacturing
AssigneeBaker Hughes Incorporated
InventorsLarry V. Dalrymple, David H. Neuroth, Phillip R. Wilbourn, Don C. Cox, Thomson H. Wallace
Life of this patent
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Abstract
A method for manufacturing an electrical cable provides an electrical cable suitable for use in heating wells. An elastomeric jacket is extruded over insulated conductors. A stainless steel plate is rolled around the jacket to form a cylindrical coiled tubing having a seam. The seam is welded, then the tubing is swaged down to a lesser diameter to cause the tubing to frictionally grip the jacket. A recess maybe formed in the jacket adjacent the seam to avoid heat damage from the welding process.
Claims19
A method for manufacturing an electrical cable, comprising:
- (a) assembling three insulated conductors in contact with each other and extruding a jacket of unexpanded elastomeric material over the insulated conductors;
- (b) rolling a metal plate around the jacket to form a cylindrical tubing having a seam;
- then
- (c) welding the seam;
- then
- (d) swaging the tubing to a lesser diameter wherein an inner wall of the tubing frictionally grips the jacket.
A method for manufacturing an electrical cable, comprising:
- (a) extruding an elastomeric jacket over at least one insulated conductor;
- (b) rolling a metal plate around the jacket to form a cylindrical tubing having a seam;
- then
- (c) welding the seam;
- then
- (d) swaging the tubing to a lesser diameter wherein an inner wall of the tubing frictionally grips the jacket;
- and wherein:
- step (a) comprises forming a longitudinal recess in the jacket;
- and
- step (b) comprises aligning the seam with the recess.
A method for manufacturing a heater cable for a well, comprising:
- (a) continuously extruding a jacket of a deformable thermoplastic material over a plurality of insulated conductors, and providing the jacket with a cylindrical exterior having a plurality of longitudinally extending grooves;
- (b) continuously rolling a metal plate around the jacket to form a cylindrical tubing having a seam;
- (c) welding the seam;
- then
- (d) swaging the tubing to a lesser diameter, wherein an inner wall of the tubing frictionally grips and deforms the jacket, and the grooves deflect to accommodate portions of the deformed material of the jacket.
A method for applying heat to a well, comprising:
- (a) forming a heater cable by extruding a jacket over a plurality of insulated conductors, rolling a metal plate around the jacket to form a cylindrical tubing having a seam, welding the seam, then swaging the tubing to a lesser diameter, wherein an inner wall of the tubing frictionally grips the jacket;
- (b) electrically joining lower ends of the conductors and deploying the heater cable into the well;
- (c) applying electrical power to the conductors to cause heat to be generate;
- and
- wherein step (a) comprises forming the cylindrical tubing with an initial inner diameter at least 0.030 inch greater than an outer diameter of the jacket.
A method for applying heat to a well, comprising:
- (a) forming a heater cable by extruding a jacket over a plurality of insulated conductors, rolling a metal plate around the jacket to form a cylindrical tubing having a seam, welding the seam, then swaging the tubing to a lesser diameter, wherein an inner wall of the tubing frictionally grips the jacket;
- (b) electrically joining lower ends of the conductors and deploying the heater cable into the well;
- (c) applying electrical power to the conductors to cause heat to be generated;
- and wherein step (b) further comprises
- closing a lower end of the tubing to prevent entry of well fluids into the interior of the tubing.
A method for applying heat to a well, comprising:
- (a) forming a heater cable by extruding a jacket over a plurality of insulated conductors, rolling a metal plate around the jacket to form a cylindrical tubing having a seam, welding the seam, then swaging the tubing to a lesser diameter, wherein an inner wall of the tubing frictionally grips the jacket;
- (b) electrically joining lower ends of the conductors and deploying the heater cable into the well;
- (c) applying electrical power to the conductors to cause heat to be generated;
- and
- wherein step (b) further comprises insulating the lower ends of the conductors from the tubing, and sealing the tubing to prevent entry of well fluids into contact with the conductors.
Dependencies are inferred from the claim text.