US2808110A - Oil well heater - Google Patents

Description

s. sPlTz OIL WELL HEATER Oct. 1, 1957 Filed Dec. 27, 1955 ood oooooooo IN V ENTOR.

United States Patent O OIL WELL HEATER Samuel Spitz, Los Angeles, Calif., assignor to Electronic Oil Well Heater Company, Los Angeles, Calif., a limited partnership, consisting of Samuel Spitz, Patrick B. Mc- Carthy and Homer C. Compton Application December 27, 1955, Serial No. 555,381

6 Claims. (Cl. 166-61) The present invention relates generally to heating apparatus and is more particularly concerned with means for the application of heat to a subterraneous passage, such -as in the case of a drilled oil well.

In its broad concept, the present invention seeks to provide an electrically energized heater for use in removing parain and asphalt which has congealed and forms a block for the ow of oil, las well as provide apparatus which may be utilized in so-called stripper wells having low oil content and high water content. The present invention is susceptible of beneficial use in both new wells and old wells. In the case of old wells, where the flow has decreased to such a l-ow value that it is uneconomical to pump the well, the subterraneous application of a sutliciently high temperature Will act to decrease the oil viscosity in the well and also in the adjacent formation and permit greater increased ow of oil. The application of heat to the water in the oil bearing formation, where the oil is particularly heavy and Where the oil sand is so tight as to restrict the oil flow, creates a gas under pressure in the well, which acts to break down the oil sand and aid in the obtaining of oil therefrom, thus increasing the well production.

Heretofore complicated and expensive arrangements utilizing `steam piping as well as electrical heaters have been utilized. In the known electrical heaters, the heater in the Well was fed through cables from the earths surface. This arrangement has been found to be impractical particularly in deep wells, due to voltage loss in the cables and concomitant loss in efficiency of operation. Moreover, these cables had to be Iof large size and were particularly expensive, in order to carry the required amount of current for the heating coil.

The present invention is particularly concerned with an electrical heater for the well, and has for one object the provision of an arrangement which will be simple of conr struction, easy to operate, which will not interferewith the normal pumping operation of the well, and which will overcome the inherent disadvantages of prior electric heaters.

A further object of the invention as herein described is to provide an electric heater with an energizing high current transformer, forming a unitary assembly which may be selectively positioned in the well at a desired point, and wherein conductors energize the transformer from a surface source yof electric power. With such an arrangement, the potential drop in the connecting conductors becomes immaterial and may be compensated for in the transformer design.

A further object of the invention as herein described is to provide novel apparatus which may be readily con- Patented Oct. l, 1957 the accompanying drawings, which are for illustrative purposes only:

Fig. 1 is a sectional view diagrammatically illustrating an oil well embodying the heater apparatus of the present invention; and

Fig. 2 is an enlarged longitudinal section through the heater apparatus, and showing the operative association of the various components thereof.

Referring now to the drawings, for illustrative purposes, there is shown in Fig. l -a typical oil well vof conventional construction including a subterraneous passage or bore 10 in which the usual casing 11 is placed with its upper end terminating at the surface, while the lower portion of the well may or may not contain a liner (not shown).

Conventional tubing 12 is shown as extending from the surface into the well, where its lowermost end is positioned below an oil level 13 of oil from the adjacent oil formation 14, which oil may be floating upon water as indicated at 15 in the well. The water and oil may enter the casing through a perforated liner (not shown) inthe usual manner familiar in the oil Well industry.

The surface end of the casing and tubing will, of course, in practice be connected with a suitable head structure (not shown). Moreover, there is positioned within the tubing 12 a conventional pump 16, which is positioned adjacent the oil well level and arranged to be raised and lowered by means of a suitable sucker rod 17 which is connected with appropriate pumping mechanism at the surface.

Heating apparatus embodying the features of .the present invention are indicated generally at A, the heating apparatus being in the form of a unitary structure which is secured to the tubing 12 so that it may be selectively positioned at the desired location in the well and locate a perforated portion 18 of the tubing 12 in the oil below the level 13. The perforated portion 18 is provided to admit oil to the pump 16 within the tubing 12.

The heating apparatus is located adjacent the perforated portion 18 of the tubing in such -a position that the heating apparatus will heat the water below the oil, and through this heated water may act to further heat the surrounding formation. Thus, the heat acts upon the oil within the casing to decrease its viscosity, and also by heating surrounding formation cause increased ow of oil and water therefrom.

The specific details of the heating apparatus will now be described by reference to Fig. 2. In the particular embodiment disclosed, a transformer structure 19 is sup` ported on a rsection of the tubing 12 by means of a tubing collar 20 which is positioned below concentrically arranged primary winding 21 and secondary winding 22 of the transformer.

The transformer is designedwith asecondary winding having a low voltage high current output from which it is possible to obtain heating currents of the order of 1000 amperes. The primary winding is arranged to be supplied through suitable conducting cables 23 from an electric source at the surface, this source being of 110, 220 or other suitable potential as currently available at the well. This is a departure from the conventional methods heretofore utilized in which the current was furnished directly through conductors to a heating coil in the well. In those arrangements, it was necessary to have large expensive conductors for carrying the heavy current, and moreover the drop in potential, particularly in deep Wells, materially affected the efficiency of the heating coil. In the present arrangement, the loss of potential in the conductors 23 may be compensated for in the design of the high current output transformer, so that a more eflicient device is obtained.

As shown, there is adjacently connected to the output of the secondary winding, a heating element 24, this heating element being spiralled in the present instance to form a heating coil around the associated tubing section and positioned above the transformer windings so as to lie between the transformer and the perforated tubing portion 18. In order to protect the heating coil, there is provided a surrounding shield 25 which is perforated to permit passage of oil and Water. The shield 25 is suitably supported at its lowermost end on the transformer, and at its upper end is held in position by a spider 26 so that a unitary assembly is obtained.

The apparatus of the invention is particularly easy to handle and locate at the desired position in the well, and by connecting the conductors 23 through an appropriate switch or circuit breaker Z7, the energization and deenergization of the transformer with its connected heating coil may be readily controlled from the surface. The supply conductors are connected in conventional manner with a voltmeter 28, and ammeter 29 from which it is possible to determine the operating condition of the heater.

From the foregoing description, it will be realized that other modifications may suggest themselves to those skilled in the art Without departing from the spirit of my invention, and, hence, I do not wish to be restricted to the specific form or forms shown or uses mentioned, except to the extent indicated in the appended claims.

I claim:

l. Heating apparatus for a well, comprising: a tubular member having a perforated wall portion; a transformer carried by said member, said transformer being spaced from said perforated portion and having a primary winding and secondary winding in inductively coupled concentric relation, the primary winding being adapted for connection with an electric supply source, and the secondary winding having a low voltage high current output; and a separate heating element closely positioned to said transformer and connected to the output of said secondary.

2. Heating apparatus for a well, comprising: a tubular member having a perforated wall portion; a transformer carried by said member, said transformer being spaced from said perforated portion and having a multiple turn primary winding and a multiple turn secondary winding in close magnetic coupled relation, the primary winding being adapted for connection with an electric supply source, and the secondary winding having a low voltage high current output; and a separate heating coil connected to the output of said secondary, and surrounding said tubular member at a position closely adjacent to said transformer, but substantially unaffected by the magnetic ilux coupling said windings.

3. Heating apparatus for a well, comprising: a tubular member having a perforated wall portion; a transformer carried by said member, said transformer being spaced from said perforated portion and having a primary multiple turn winding and secondary multiple turn winding in concentric relation surrounding said tubular member, the primary winding being adapted for connection with an electric supply source, and the secondary winding having a low voltage high current output; and a separate heating coil closely positioned in end-to-end relation to said transformer windings and connected to the output of said secondary winding, whereby the heating effect is concentrated in said heating coil and not in the transformer windings.

4. Heating apparatus for a Well, comprising: a tubular member having a perforated wall portion; a transformer carried by said member, said transformer being spaced from said perforated portion and having a primary multiple turn winding and secondary multiple turn winding in concentric relation surrounding said tubular member, the primary winding being adapted for connection with an electric supply source, and the secondary winding having a low voltage high current output; and a separate heating coil connected to the output of said secondary Winding, said coil having spaced apart turns surrounding said tubular member at a position axially spaced from said transformer windings, whereby well fluid is free to flow around the coil turns of the heating coil.

5. Heating apparatus for a well, comprising: a tubular v member having a perforated wall portion; a transformer carried by said member, said transformer being spaced from said perforated portion and having a primary Winding and secondary winding in concentric relation surrounding said tubular member, the primary winding being adapted for connection with an electric supply source, and the secondary winding having a low voltage high current output; a heating coil connected to the output of said secondary Winding surrounding said tubular member at a position closely adjacent to said transformer; and a shield having openings therein, said shield surrounding said member and heating coil, and being positioned at a location between said transformer and the perforated wall portion of the tubular member.

6. Apparatus for heating a liquid in an oil well, comprising: a tubular member having a perforated wall portion; a transformer carried by said member, said transformer having a primary winding adapted for connection with an electric supply source, and a secondary winding having a high current output; a heating element positioned adjacent said perforated wall portion connected to the output of said secondary winding; and a perforated shield surrounding said tubular member and heating coil.

References Cited in the file of this patent UNITED STATES PATENTS 522,737 Lucock July 10, 1894 806,039 Williamson et al Nov. 28, 1905 1,354,757 Popcke et al Oct. 5, 1920 2,302,774 Jarvis Nov. 24, 1942

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