Heater utilizing copper-nickel alloy core
AssigneeShell Oil Company
InventorCornelius F. H. Van Egmond
Life of this patent
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Abstract
An electrical resistance heater is provided which utilizes a copper-nickel alloy heating cable. This metallurgy heating cable is significantly less prone to failure due to localized overheating because the alloy has a low temperature coefficient of resistance. Used as a well heater, the heating cable permits heating of long segments of subterranean earth formation with a power supply of 400 to 1200 volts.
Claims13
A long electrical heater comprising:
- a) at least one electrical heating cable having a heating core, the core comprising about 6 percent by weight nickel and about 94 percent by weight of copper;
- and
- b) a means for supplying electric current through the electrical heating cable.
The heater of claim 9 wherein the heater comprises a core which consists essentially of about 6 percent by weight nickel and about 94 percent by weight copper.
The heater of claim 11 wherein the two cores within the sheath are connected at the bottom.
A well heater comprising:
- a) at least one heating section which
- i) is capable of extending for at least a hundred feet within a well borehole adjacent to an interval of subterranean earth formation to be heated,
- ii) contains at least one electrical heating cable, and
- iii) contains a combination of heating cable core resistance and core cross-sectional areas capable of producing temperatures between about 600.degree. C. and 1000.degree. C. within the subterranean earth formation, wherein the heating cable is an electrical resistance heating cable comprising:
- a core consisting essentially of 6 percent by weight nickel and 94 percent by weight copper;
- electrical insulation surrounding the core;
- and surrounding the electrical insulation, a metal sheath;
- and
- b) a means of supplying electrical power to the heating cable core.
Dependencies are inferred from the claim text.