US2444756A - Apparatus for progressively heating oil sands surrounding oil wells - Google Patents

Description

y '6, 148 R. M. STEFFEN 2,444,756 APPARATUS FOR PROGRESSIVELY HEATING OIL SANDS SURROUNDING OIL WELLS I 4 Filed Jan.

Patented July 6, 1948 APPARATUS FOR PROGRESSIVELY HEAT- SURROUNDING OIL IN G OIL SANDS WELLS Ralph M. Steffen, North Hollywood, Calif., assignor to National Secondary Recovery Corporation, Reno, Nevada, a

corporation of Nevada Application January 4, 1946, Serial No. 639,126

6 Claims. (Cl. 16617)" This invention relates to. apparatus for progressively heating oil sands surrounding an oil well.

The primary object of this invention is to provide a novel apparatus for augmenting the yield from oil wells. 1.

An important object of the invention is the provision of apparatus which is applicable to existing wells to renew or increase this output, or which may be employed with equal facility in low yield shale and oil .sands and in fields where normal procedures for development of the .oil deposits are not practicable.

A further important object of the invention is the development of apparatus which shall concurrently condition the oil strata for increased oil flow and effect an increased output from the well.

A still further important object of the invention is the provision of an improved apparatus for efiiciently heating the oil bearing sands from i an immersion type heater which may be adjustably positioned in a Well.

An additional object of the invention is the provision of an apparatus for heating the bottom portion of an oil well provided with a perforated casing and with an oi1 pump whereby the surrounding oil sands are progressively heated radially of the well for facilitating flow of oil from the sands into the Well.

A further object of the invention is the provision of an apparatus for heating the oil sands surrounding an oil well having a perforated casing and an oil pump therein by the ignition of successive charges of combustible gas confined within a tubular heating coil surrounding the pump tubing, whereby heat is radiated from the walls of the coil and is transmitted through the casing and perforations into the surrounding oil sand for progressively heating in successive zones radially of the well for facilitating flow of oil from the sands to the well aswell as to adjoining wells.

A still .further object of the invention is the provision of a relatively simple and effective apparatus for carrying. the method into eifect.

With the above recited and other objects in view, the invention is set forth in thefollowing specification and illustrated in the accompanying drawing, wherein Fig. 1 is a vertical sectional view coaxially of a well and illustrating successive zones of oil sand in surrounding relation to the well;

Fig. 2 is a transverse sectional view substantially in the plane of line 22, Fig. l.

Referring now in detail to the drawing, the numeral Ill designates a well casing which may be provided with perforations II in the lower end portion thereof. A pump delivery tubing I2 is disposed within the well casing I0 coaxially thereof and near its lower end may be provided with a flanged collar, such as indicated at I 3. The pump tubing at its upper exposed end is provided with an oil delivery conduit. I 4 provided with a valve I5. A pump sucker rod I6 extends downwardly within the tubing I2, and at its lower end is connected with the pump I1, and at its upper end is connected with the pump jack I8. By this mechanism, oil is pumped from the bottom of the well, as in usual practice. It frequently occurs, however, that when a well ceases flowing, after pumping, that there still remains a residuum of oil in the strata, which, owing to its viscosity or the temperature of the strata has not heretofore been profitably recoverable. If, however, this strata can be effectively treated with heat, considerable oil can be induced to flow into the well and be reclaimed.

This important desideratum is effected by the novel heating device now to be set forth.

In accordance with the present invention, a tubular coil I9 surrounds the pump tubing I2 below the flange I3 and is supported thereon, and as illustrated the diameter of the coil is suchas to enable it to be lowered into the well and over the flange I3. The coil is preferably double or one which extends downwardly from the flange I3 andthence upwardly to the flange. This arrangement not only avoids terminating the coil below the maximum oil level in the well, but of more importance provides a greater heat radiating surface on the coil.

The coil as formed has two upper ends, one of which terminates above the maximum oil level in the form of a gooseneck I9. To the other end of the coil is suitably secured the lower end of a tube or conduit 20 which is extended at its upper end along the ground surface, preferably by the provision of additional conduit lengths. The conduit 20 above the well is provided with f ."ergized'so asto produce a check valve 2|, and is further provided with a spark plug 22, energized by an ignition circuit, not shown, between the check valve and the top of easing Ill.

In assembly, the coil 19 is lowered into the well by means of conduit 20 which in practice is constructed of readily attached successive sections, thus facilitating the positioning of the coil. It will be here noted that the flange and coil may be progressively lowered or raised in the welltin'nonformity "with archanging'oil level. The coilis. suspended in the well in surrounding relation to the pump tubing 12 and from the flange 13. The tubing from which the coil "I 9 is formed is preferably about .twodnehesdnadiameter, while the diameter of tube qorz-conduitizfl is about one-half inch in diameter, for the pur pose later to appear.

In operation of the structurejdisclosediincarrying the heating method into reflect, 'a--combustible gas is admitted through the check valve 2| into conduit extending. downwardlyiwithin the casing Ill and thence into the coil l9. When a combustible chargehas filled the coil substantially, to the end I9 thereof, the plug 22 is en a spark and the charge thus ignited. q H

The burninggase'swithin the-coil l9 heat-the tube wallsjthereof and the heat-radiated therefrom travels through the surrounding oil medium andithence through-casing l0 and into the oil -sand, asindicated 1 by the arrows having'open fiheads, and as identified in the legend on the drawing. tThegas' is admitted tothe coil and igllitd about'ten;times per minute with the re- .Lsult that. heat is continuously generated and radiatedfromthecoil. As a resu1t,'the zone of the oil sandjlindicated as .Awill become heated and .the heat;will progressively penetrate the zones "B and C .whereby the oil sands will become iheated'fona substantial'distance from the'well, and oil-will; thus be caused'to flowtherefromto- "wardend intothe well, ,as' is indicated by the .;arrows -having solid heads. Furthermore, this ,progressive heating of the oil sands will-result ;in stimulating and-facilitating "the flow "of oil fin'thefield. as a whole to adjacent wells.

While'the zones A, Band-C are indicated as distinct,;.such is for purpose of explanation only,

asthere is of course no clear line of demarcation between" the. successive zones referred to.

As before. stated, the relatively large tube diameterof the coil provides a desirablylargeheat radiating surface, while the substantially Smaller tubeifi, due to its relativesmallsurface; is rapidly .cooledby' thegas entering prior to ignition thereof, 'ther'ebyavoiding an otherwise overheated condition 'occasioning 'pre-ig-nition and "damage ftherfrom. The operation as abovedescr'ibed maybe continuoussince .the plug 22,.may be energizedat regular timed.intervals'.by any suitable: control ..means, and the check valve 2| will admit gas gprior to ignition and .will restrict the-flow immediately .following ignition due to increased pressure in tube zfl'andcoil l9. Upon-reduction of pressure within the, coilafterthe ignition, combustible gas will again be admitted through valveZi which will drive the" burned hotygases 'outthrough the open end l9f of-thecoil thereby 'f-urtherheating the well and'oil sand.

.It shouldbeunderstood here that I-contemplate availing myself "of a variety (if-instrumen- "ztalitiesfm effecting this operation. 'Thecom- *bustible mixturemay be supplied under any desirable pressure, it being evident that I may vary the same during the operation to meet varying local conditions. Further, the top of the well casing may be enclosed, with a controllable vent, whereby a back pressure may be maintained, in certain instances, in the casing and coil, with beneficial influence upon the rate and extent of heat propagation through the concentric zones A, B and C. By reason of the unidirectional flow of the fuel mixture, more even heating and bettersoavenging of the heatingtelementfis'obtained, which are-important advantages, particularly in view Of the frequent extreme depths at which pumping is often required.

:Itriseto-tbeeparticularly observed that the coil "-l'filis ofiaiiengthtto traverse a substantial depth of the sandrand-rdue to its duplex form, a substantially large heat radiating surface is provided.

=Whil-e?l:havefdisclosed the invention in accordance "with "a single specific embodiment thereof; the same'is to be considered as illustrafiYGEDIY,-2&Hdiflr0t restrictive, the scope of the invention being defined in the sub-joined claims.

1. Apparatus for progressively heating successive-zonesof oil'sand-'ra'dially of -a=well having a perforated casing and-a pump supported therein by a tubing extending axially of the well-to a point exteriorly-theredf, =comprising a tubular -coil surrounding the pump tubing, aconduitconnected with an end of the coil and extending upwardlythrough the well'and externally thereof "to point of combustible gas supply, a check "valve in the -'conduit fonadm-itting successive chargesof -combustible-gas to the coil and=means 'fordgriiting theflsuccessive gas'charges whereby *the'coilwall isheated and the heat radiated therefrom through the -'casing perforations and intothe' surroundingoilsand; said coil being suspended 'from a flange on -the pump tubing, the inner diameter "of said cell being greater than the diameter of theilange' to facilitate admission of the coil over the tubing and into the well. f2. Apparatus"for progressively'heat-ing successive zones of ofl san'd radially of 'a we'llhaving "a perforated "casing and -a pump supported therein'by atubing-extending axiallyof the well to a point exteriorly thereof; comprising a tubular-coil-surrounding the pump tubing, a-conduit *connctedwith an end of the-coil and extending upwardly through thewell and externally thereof toa-point of 'combu'stible'gas supply, a check valve in the conduit for admitting successive charges'of combustible gas to the coil'and means for igniting the successive'gas chargeswhereby "the coil wall isheated and" the heat radiated "therefromwhrough the casing perforations and "into the surrounding oil sand, the coil tube be- "ing'of relatively larger diameter'and the conduitof relativelysmaller-diameter.

3. *Apparatus for heating'the oil-sand strata radially of 'an'oil --well I having a pump supported {therein by a tubing extending axially of "the well "to "an exterior point, comprising; a 5 supporting "member-on-said"tubing,"a tubular coil surrounding 'the'tubing and carried'bysaid supporting merfrber, a conduit connected with said-coil and extending ext-eriorly of said well to a source'of "combustible gas; a valvein said conduit for admittingsuccessive charges of combustible gas to the-coil, and-means for ignitingthe'successive gas "charges 'for heating said coil and thereby 'the'surroundingroilsand strata.

4.*The pom-binationof -claim 3 "wherein "said conduit is of less cross-sectionalarea thansaid RALPH M. STEFFEN.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Harris Feb. 19, 1878 Elten Apr. 26, 1910 Breitung et a1. Sept. 7, 1915 Drinkern July 15, 1919 Kreager May 3, 1927 Hixon Sept. 19, 1939 Pick Dec. 7, 1943

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