Downhole radial flow steam generator for oil wells

• US 5,623,576 A
• Filed: 07/26/1994
• Issued: 04/22/1997
• Est. Priority Date: 07/26/1993
• Status: Expired due to Term

• Current Assignee: Meshekow Oil Recovery Corporation
• Original Assignee: Meshekow Oil Recovery Corporation
• Inventors: Deans, Harry A.
• Primary Examiner(s): Jeffery, John A.
• Application Number:
  US08/280,739
• Time in Patent Office: 1,001 Days
• Field of Search: 392/301, 392/303, 392/305, 392/306, 166/60, 166/302
• US Class Current: 392/303
• CPC Class Codes: E21B 36/04 using electrical heaters
• CPC Class Codes: E21B 43/2401 by means of electricity
• CPC Class Codes: F22B 1/30 Electrode boilers
• CPC Class Codes: H05B 3/0004 Devices wherein the heating current flows through the material to be heated Circuit arrangements for heating by passing the current directly across the material to be heated H05B3/0023; granular, powdered or fluid material H05B3/60

Abstract

A downhole radial flow steam generator for oil wells that includes an annular casing and a water passage extending therethrough with a porous medium between the casing and passage with electrode means within the generator to heat the water into steam or hot water wherein the fluid is directed radially through the medium and the annular casing into a preselected earth strata to heat oil therein and reduce its viscosity for pumping to the surface.

Claims

1. A downhole radial flow steam generator for oil wells that is adapted to be inserted into an annular well casing having openings therethrough, said generator adapted to be suspended from a flexible cable that carries water and electricity to said generator from above ground comprising:

an outer casing of a diameter less than interior diameter of aid annular well casing and having a construction to allow steam generated therein to radially pass therethrough and through said well casing;

at least two spaced apart electrodes adapted to be chargeable from said flexible cable forming a part of said generator, to convert water therebetween supplied from said flexible cable to steam; and

a non-conductive porous medium packed in said outer casing between electrodes and of such a construction adapted to allow steam and brine to pass through said outer casing, said medium is of such a configuration as to provide circuitous passages to allow flow resistance to water and steam and said medium is capable of receiving water to wet, said medium allowing a path for electric current while also allowing steam to pass therethrough.

2. A downhole radial flow steam generator system as defined in claim 1 wherein:

said flexible suspension cable includes one or more electrical conductors extending to said generator; and

a reinforcing member is included within the cable extending the depth that said cable may be used.

3. A downhole radial flow steam generator system as defined in claim 1 wherein:

there is a pre-heating channel to receive water from said water passage before being converted to steam.

4. A downhole radial flow steam generator for oil wells as defined in claim 1 wherein:

said electrodes are made of a sintered metal which is adapted to allow indirect passage of water and steam therethrough.

5. A downhole radial flow steam generator for oil wells as defined in claim 1 wherein:

said outer casing is annular, and

said electrodes are annular disks that fit within said casing and engage the casing therearound with one disk spaced from the other; and

said disks are adapted to indirectly channel water therethrough into said porous medium where steam may be forced radially out from said generator.

6. A downhole radial flow steam generator for oil wells as defined in claim 5 wherein:

there are three electrodes fitted within said casing with said porous medium packed therebetween.

7. A downhole radial flow steam generator for oil wells as defined in claim 5 wherein:

each of said annular disk electrodes include a top and bottom surface generally parallel with each other, and

each disk includes at least one packing channel passing through from said top and bottom surface to allow said porous medium to pass therethrough to fill chambers therebelow.

8. A downhole radial flow steam generator for oil wells as defined in claim 1, wherein:

said porous medium is ceramic beads of such a configuration as to provide circuitous passages for said steam passing therethrough.

9. A downhole radial flow steam generator unit wherein a plurality of steam generators, each defined as in claim 1, are fixed together for simultaneous steam production.

10. A downhole radial flow steam generator unit for oil wells as defined in claim 9 wherein:

each generator includes top and bottom coupling means adapted to carry electricity and water from one generator to the other.

11. A downhole radial flow generator system comprising at least one downhole radial flow generator, said system capable of creating steam or hot water and said generator is adapted for insertion into a bore, said generator suspended from a flexible cable that carries conductive salt water and high voltage current to said generator from above ground, said generator comprising:

an outer casing of a diameter less than the interior diameter of said annular bore;

an inner electrically non-conductive casing abutting said outer casing;

a pair of annular porous electrodes one high voltage and one ground each spaced one from the other in said inner casing forming top and bottom porous cap elements to allow water to indirectly percolate therethrough and said high voltage current passes to said electrodes from a position at least adjacent to the inner annular casing and said electric current passes to conductive brine passing therethrough;

at least one water passage from said flexible cable extending into said generator at least adjacent to said inner annular casing;

a porous non conductive non heat transferring medium packed into said inner casing between said electrodes having connected voids therethrough whereby fluid is capable of circuitously passing through; and

said brine will wet said medium to assure a conductive path for electric current while providing for a passage of steam through said medium; and

a donut shaped bottom retainer ring having an interior void adjacent said ground electrode wherein either said steam or hot water generated will pass through said void in said retainer ring and radially outwardly therefrom into earth to be treated.

12. A downhole radial flow generator system as defined in claim 11 wherein:

there are a set of three generators arranged in a three-phase y configuration for simultaneously creating steam or hot water, said generators arranged in vertically spaced relationship;

said generators each include separate passage means at least adjacent to said inner casing to carry said hot water and said high voltage to each of said generators; and

an elongated annular sleeve surrounding said generators, said sleeve include vertical slots therein in the area between said generators to allow said steam or hot brine to radially escape into an appropriate earth formation.

13. A downhole radial flow generator system as defined in claim 12 wherein:

there is a separate water passage and high voltage passages to each set of generators.

14. A downhole radial flow generator system of claim 11 wherein:

a feedwater preheat channel connects to said water passage projecting upward at least adjacent to said casing; and

a water passage over said top positive electrode is adapted to feed preheated water to said top positive electrode.

15. A downhole radial flow generator as defined in claim 11 wherein;

said electrodes are permeable carbon material which is adapted to allow percolation passage or water or steam therethrough.

16. A downhole radial flow generator as defined in claim 11 wherein:

a high voltage wire is provided carrying current from said flexible cable and said water passages are formed in said annular inner casing.

17. A downhole radial flow generator as defined in claim 11 wherein said inner electrically non-conductive casing is formed of ceramic.

18. A downhole radial flow generator as defined in claim 11 wherein said at least one water passage is at least one tube mounted inwardly of said inner electrically non-conductive casing.

19. A downhole radial flow generator as defined in claim 11 wherein:

an insulated high voltage wire carrying current from said flexible cable is mounted within said inner electrically non-conductive casing.

20. A downhole radial flow generator as defined in claim 11 wherein:

said porous non-conductive medium is a plurality of ceramic beads packed together.