Claims
- 1. A system for heating a well tubing comprising,
- a petroleum well having a metal casing and a metal wellhead at the upper end of the casing,
- a metal tubing suspended from said wellhead within said casing and providing with said casing an annular area adjacent to said wellhead, and
- means for generating in said annular area microwaves in at least one mode which naturally occurs in and is transmitted axially along said annulus including a source of microwaves at 2450 MH.sub.z and a wave guide exterior of the well communicating such source with said annular area.
- 2. The system of claim 1 wherein the means for generating microwaves includes
- coupling means for electrically coupling the wave guide to said annulus.
- 3. The system of claim 1 wherein a well pump and sucker rod string therefor are located in the tubing.
- 4. The system of claim 2 wherein
- the wave guide is rectangular with its horizontal dimension greater than its vertical dimension, and
- said coupling means is provided by plural slots extending horizontal through said casing.
- 5. The system of claim 4 wherein said coupling means includes at least three slots.
- 6. The system of claim 4 wherein said slots extend horizontally approximately 2 inches to 2.6 inches in length measured as a chord between the slot ends, and
- the source generates waves at 2450 MH.sub.z.
- 7. The system of claim 6 wherein said slots have a vertical dimension of approximately 1/8".
- 8. The system of claim 4, 5, 6 or 7 wherein a ceramic barrier prevents flow through said slots.
- 9. The system of claim 8 wherein the ceramic barrier is positioned internally of said casing and is sealed thereto and prevents contamination of and fluid flow through said slots.
- 10. The system of claim 4 wherein
- said casing includes a metal pipe coupling through which said slots extend,
- said pipe coupling has a larger inner diameter than the casing immediately there below,
- a ceramic ring is sealingly secured in said pipe coupling and overlying said slots, and
- metal means is carried by said tubing and projects into said annulus opposite said slots.
- 11. The system of claim 1, or 3 wherein
- said wellhead has a threaded port in its side wall immediately below the slip bowl in said wellhead, and
- said means for generating waves is coupled to said annulus through a nipple secured in said port.
- 12. The system of claim 11 wherein
- a rod is supported in said nipple with one end extending toward said tubing,
- said nipple and rod terminating adjacent but not intruding to any substantial degree into said annulus, and
- said rod having an enlargement adjacent to said annulus.
- 13. The system of claim 11 wherein
- a rod is supported in said nipple with one end extending toward said tubing,
- said nipple and rod providing a coaxial wave guide,
- said nipple and rod terminating adjacent but not intruding to any substantial degree into said annulus, and
- said rod having an enlargement adjacent said annulus, said rod having its other end in electrical contact with said nipple.
- 14. The system of claim 13 wherein said enlargement is a disc on the end of said rod.
- 15. The system of claim 13 wherein said enlargement is a rod perpendicular to said first mentioned rod.
- 16. The system of claim 12 wherein said nipple has an inner diameter and said enlargement has a dimension in a direction normal to said rod at least as large as approximately 1/4 wave length of a wave mode possible in said annulus.
- 17. The method of heating the tubing of a well having a metal casing with a metal wellhead at its upper end and a metal tubing suspended from the wellhead to inhibit the formation of solids in the well tubing comprising,
- generating microwaves at 2450 MH.sub.z and transmitting the microwaves through a wave guide exterior of the well to the annulus between the casing and tubing in the area immediately below the wellhead,
- said waves being in at least one mode which naturally occurs in and is transmitted axially along said annulus.
- 18. The system of claim 13, wherein said nipple has an inner diameter and said enlargement has a dimension in a direction normal to said rod at least as large as approximately 1/4 wave length of a wave mode possible in said annulus.
- 19. The system of claim 14, wherein said nipple has an inner diameter and said enlargement has a dimension in a direction normal to said rod at least as large as approximately 1/4 wave length of a wave mode possible in said annulus.
- 20. The system of claim 15, wherein said nipple has an inner diameter and said enlargement has a dimension in a direction normal to said rod at least as large as approximately 1/4 wave length of a wave mode possible in said annulus.
Parent Case Info
This application is a continuation of our copending application Ser. No. 762,697, filed Aug. 5, 1985 now abandoned.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
Country |
Parent |
762697 |
Aug 1985 |
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