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
Estimating the term…
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.
Claims23
A cable for deployment in a well, comprising:
- at least one insulated conductor;
- an elastomeric jacket extruded over the insulated conductor, the jacket having a cylindrical exterior that has a longitudinally extending recess formed thereon;
- and
- a metal tubing having a cylindrical inner wall and a longitudinally extending weld seam, the tubing enclosing the jacket with the inner wall in frictional engagement with the cylindrical exterior of the jacket, the seam being located adjacent the recess so as to avoid excessive heat to the jacket while the seam is being welded.
A cable for applying heat to a well, comprising:
- a plurality of insulated conductors;
- a jacket extruded directly over the insulated conductors, the jacket having a cylindrical exterior with a plurality of spaced apart longitudinally extending grooves and a longitudinally extending recess formed thereon, the recess intersecting the cylindrical surface at two point in the range from 50 to 90 degrees apart, the recess having a base that is located a selected distance from the seam, the selected distance divided by a radius of the inner wall of the tubing being the range from 0.15 to 0.35;
- and
- a stainless steel tubing having a cylindrical inner wall and a longitudinally extending weld seam, the tubing having an outer diameter no greater than one inch, the tubing enclosing the jacket with the inner wall in frictional engagement with the jacket and the seam located adjacent the recess so as to avoid excessive heat to the jacket while the seam is being welded.
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.
A method for manufacturing a heater cable for a well, comprising:
- (a) continuously extruding a jacket over a plurality of insulated conductors, and providing the jacket with a cylindrical exterior having a plurality of longitudinally extending grooves and a longitudinally extending recess formed thereon;
- (b) continuously rolling a stainless steel plate around the jacket to form a cylindrical tubing having a seam that is positioned over the recess in the jacket, and providing the tubing with an initial inner diameter that is greater than an outer diameter of the jacket;
- (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 applying heat to a well having a production tubing suspended within casing, defining a tubing annulus between the casing and the production tubing, the method comprising:
- (a) forming a heater cable by extruding a jacket over a plurality of insulated conductors, rolling a stainless steel plate around the jacket to form a cylindrical coiled tubing having a seam and an initial inner diameter that is greater than an outer diameter of the jacket, welding the seam, then swaging the coiled tubing to a lesser diameter, wherein an inner wall of the coiled tubing frictionally grips the jacket;
- (b) electrically joining lower ends of the conductors and deploying the heater cable into the production tubing;
- (c) with a vacuum pump located at the surface of the well, reducing pressure within the tubing annulus to below atmospheric pressure;
- and
- (d) applying electrical power to the conductors to cause heat to be generated.
Dependencies are inferred from the claim text.