US1169261A - Cleaning oil-wells. - Google Patents

Description

W. D. HUFF.

CLEANING OIL WELLS.

APPLIQATION FILED APR. 28. 1915.

Patentad Jai1.25,1916.

WILLIAM DANIEIIIEUFF, OF LA FAYETTE, LOUISIANA, ASSIGNOR F THREE-FOURTHS TO LOUISE GUIDRY MOSS, OF NEWIBERIA, LOUISIANA.

CLEANING OIL-WELLS.

Specification of Letters Patent.

Patented Jan. 25, 1916.

Original application filed April 6, 1915, Serial No. 19,607. Divided and this application filed April 28, 1915.

Serial No. 24,463.

To all whom it may concern."

Be it known that 1,.WILLIAM I). Home, a citizen of the United States, residing at La Fayette, in the parish of Lafayette and State of Louisiana, have invented certain new and useful Improvements in Cleaning Oil-Wells; and I do hereby declare the following to be a full, clear, and exact descrip-' tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In my Patent 'No. 1140982, granted May 25, 1915, and entitled improvements in operating oil wells, I have described a process and apparatus for lifting the contents ofthe well by means of the gaseous pressure generated in the well casing'by heating up the liquid contents occurring in the bottom of said casing, and causing the steam and other gases so generated to flow through ejector nozzles provided "in an inner pipe in the well "casing, causing the liquid to flow from the 'bottomof the well upthrough said inner pipe and out atv the surface, as fully described" in the application aforesaid.-

In the same patent. I have described as a part/of the operation of the 'oil well in the manner stated, the use of the apparatus for carrying out the process of cleansing the. well and the well screen; and for thinning the oil and promotingthe flow of the oilfrom the well at such-times as the well and its screen may need cleansing. In this process of cleansing the well 'andits screen, I

temporarily suspend the action of the ejector, and heat up the liquid in the well-to such. atemperature as to generate suflicient gaseous pressure to force the heated liquid through the screen baekinto thetoil-bearing 40 strata of he well. This will heat .up'the strata an will thin the oil, and melt any parafiin, or similar ingredients, which tend to thicken theoil and retard itsflow, and incidentally will also cleanse the screenby causing aflowofhot liquid out through the screen. i t i If a single discharge of heated liquid from the bottom of the well casing out through:

.the screen and into the oil-bearing strata is not suflicient, the pressure may be removed and liquid may be permitted to flow back into the well casing, when the process of heating up the liquid in the well casing and discharging it back into the oil-bearing strata may be repeated a suflicient number of tlmes to insure the thorough cleansing of the well, and incidentally, a thorough cleansing of the screen.-

This process, while described in the patent aforesaid, was not claimed therein, being fora separate invention from the lifting process which was claimed in said application, and is more fully described and claimed herein; this being a division of the application aforesaid.

My invention will be more clearly understood by reference to the accompanying drawings, in which the same parts are indicated by the same reference symbolsthroughout the severalviews.

. Figure 1 shows a section through the well casing and well, with the inner tube in elevation, and the electric heating arrangement shown diagrammatically, parts being broken away; Fig. 2 shows a central vertical section through the ejector, but on a larger scale than in Fig. 1; Fig. 3 shows a section along the line 33 of Fig. 2, and looking The well casing 1 is preferably constructasis well known in the art, may be used if desired.

The top section of the casing is perforated, as at 3, t9 receive the relief pipe 4 carrying the relief valve 4, the pressure gage 5, and a suitable safety valve 6.

The upper end of the casing is screwthreaded, as at 7, to engage the screw cap 8 beneath which is preferably placed a suitable packing 9. This cap is provided'with f ll. suitable stufiing box 10,.through which' passesthe inner/pipe 11, which inner pipe of sections connected together, and the lower section or sections of the pipe are preferably perforated, as at '12, to permit the flowof said liquid into said pipe from the interior of the casing; 1. The upper portion of this inner pipe 11- terminates in a delivery pipe-14'for the liquids is also made up." in the usual way of a series "delivered fromthe well to any desired receptacle, not shown, and this pipe 14 is con- I trolled by a Valve 15;

I provide on the 1 as electric heaters 21, which are preferably cylindrical in shape and surround the inner-- pipe 11, as shown, Any suitable heater, whether electric or of other construction, may be used in this connection; and I do not claim anyfspecial form of heater as part of my invention. The electric heaters shown are supplied with electricity from the individual feed wires" 22, which are bound up .in asuitable insulated cable23, which cable is secured'to' thelnner pipe in any conven ient way, as by the strips 24. This cable passes up through a plug 25 in the well casing and the individual conductors "are con- 1 switchboard 26, each of which switches isnected to separate switches located inthe 1 adapted to make connection withthe main 27 which is "supplied with electricity from any suitable source, as the dynamo 28. The

return main 29 is grounded in any convenientway, preferably by connecting same to 1 the finnerpipe 11, as shown in Fig.1, thus l providinganall-metalliccircuit for the electI'IClty.

r I 301 v Q volt-- meter, indicated by V, is preferably provided, and suitable resistance coils and ammetersA may be provided for each switch, as shown in Fig. 1. The electric cdnnectionspare shown diagrammatically in said figure, but the apparatus is intended to provide means for heating each electric v coil, and for regulating the temperature, of v 7 each coil, independently of all the others.

I. provide a suitable ejector for use onthe well known principle of such apparatus,

comprising a short bulbous connection 40 between the adjacent lengths of the inner pipe 11, which connection is .attached tothe convenient'way,,las by the coupling 41; and

upper portion of the inner pipell in any mounted in the upper, endof this bulbous connection 40,.i's the upper nozzle 43 of the ejector, which upper nozzle is provided with a conical-chamber, into which projects .the .upper end of the inlet nozzle 45, as

'Sll0W11 mOSb clearly in Fig. 5. This lower;- nozz le should be preferably steadied in the I i connection 40,1and I have shown a spider 46 used/for this purpose, which spider is preferably made three-legged in order to be f conveniently slipped into place in the connection .40, and may be held in place in any convenientgway, as by the screw bolts 47.

f Anysuitable -mode of mounting the ejec- "tor maybe employed.

.To;'ra1seyand lower'the inner tube in the 'ell, a; sii'table hoist 50 may be attached to hej topggof'f'sald tube; and the raising and llowering may be accomplished by the appaterior of the casing;- sultable heatmg devices such, for instance,

Between the-mains 27 and 29 a suitable ratus (not shown) installed when the well is bored and used in handling the pipes.

In oil wells there is nearly always'more "or lesslwater, and in those wells that require pumping, or. in old or abandoned wells, there-is often considerable water to be removedbefore the well can be caused to. deliver the crude oil properly.

In the operation of the device, thelfirst point is to determine the depth below the XX of the liquid in the well; this may be done by a floating plummet introduced into the well before the cap'is put on, as is well known in the art. Having'determined the depth of'the static head, and incldentally the height the liquid is to be raised above the static head, I submerge the ejector to a pointysuiiiciently below the static hadtozre quire adequatepressure to be generated in therein below the locationof said. ejector, in order to give pressure sufiiclent to cause the ejector to lift the column'of liquid in the-inner tube to the surface of the ground.

Suppose, for instance, the static head .to be 400 feet below the surface of the ground,

' and assuming the casing to be strong enough to stand an internal pressure of say 400 pounds per square inch, the ejector. inlet should preferably be about 1200 feet below the surface of the ground. Then the cap of the w'ell'being closed, and the electric con nections made, electricity is turned on to operate the submerged heaters, with-the result that the liquid in the well casing is heated and steam and hydrocarbon gases are generated, which steam andother-gase's will rise up through the liquid and accumulate in the top of the well casing,,forcing the liquid down in said casing from the level indicated at XX, or static head,

to a point below the inlet opening "of the ejector.

When there 1s only water in the wellfea'sgenerated, and hereinafter "whenever the words gas, or gas pressure, .or gaseous pressure, are used, I mean t'ofinclude inthese generic terms steam and steam the term liquid to include water and such other liquid or semi-liquld composition or mixtures of matter as are found in wells of liquid a be; low the inlet opening 48 of the inlet nozzle .45, there will be a'rush of steam, and genthe character described. When the surface of the surface of the ground of the static head the casing to depress the level of the liquid :ing, steam, of course, will be the only gas pressure;..and'in the same way I" mean by I rapid inrush of gases into the ejector, the steam, and other gases, entering the column of liquid above the nozzle 43 will also tend to promote the upward flow of the column of liquid above the nozzle 43 under the well known principle of the aerial column, as shown, for instance, in the patents to J. G. Pohle, entitled process of elevating liquids, No. 487639, granted December 6, 1892, and No. 532699 for process of-and apparatus for elevating liquids, granted January 15, 1895. Furthermore,the mixture of liquid and gas will be lighter than a similar column of liquid alone, and the pressure required to lift the superposed column in the inner pipe will be materially decreased.

Suitable heaters may be provided along the length of the inner pipe 11 above the ejector, whereby a high temperature of the liquid, and more especially of the gases cpntained therein, may b secured, with the result that the buoying-up effect of the gases may be materially increased. If there be free'liquid connection between the oil-bearing strata of the well and the screen and bottom of the well casing, as in free flowing wells, the height of the liquid in the inner tube will remain constant, corresponding to the normal static head of the well, irrespectii e of the gas pressure in the well casing, until the gas can get into the ejector nozzle; but should the flow of the well be slow and the gas pressure be suddenly raised there, would be a lifting of the column in the inner tube to balance the excess gas pressure in the casing, which might under certain circumstances be sufficient to cause the liquid to flow out of the top of the inner tube';' bu t this lifting of the inner columnof liquid by pressure alone will have no other effect than the advantageous one of facilitating the starting up of the operation after )the gas gets below the inlet nozzle of the ejector, when the operation into the bottom of the well, It will be obvious that the actual height the liquid'has to be raised is determined by the depth of;

gtime the steam would rush out through the the normal static headof the well below the surface of the ground.

I The operation of the apparatus as hereinbefore described will continue indefinitely as long as the flow of oil continues through 5 the screen, near the lower end of the casing,

and adequate pressure is maintained in the upper end of the casing above the liquid therein. But should the flowof oil through the screen be diminished, due to the thick- 1 ening of the oil in the oil-bearing strata, the clogging up of the screen, or other causes, and it be necessary or advisable to warm and consequently thin the consistency of the oil inthe region surrounding the screen, or to cleanse the screen by sending under the ejector principle becomes continu: ous, and commensurateiwith the flow of oil 0 the level of the hot liquld 1n the casing was Zia a reverse current of hot liquid therethrough,

the valve 15 is closed, and the pressure is permltted to escape from thecasing through the valye 4, permitting the liquid in the casing to assume the normal static head. Then close the valve 4 and heat the column of liquid in the well casing to a temperature high enough to generate suflicient gaseous 212'F.- to secure gaseous pressureenough to force-the level of the liquid down any material distance against the upward pressure due to the-normal static head, and thus the liquid forced out of the well casing back into the oil-bearing strata will be quite hot when it flows outward through the screen.

If a single discharge of the heated liquid in the casing back through the screen and into the oil-bearing strata be not suflicient, this heating process can be repeated until the strata are adequately heated to permit the free flow of the oil in the well again. Of course, the flow of heated liquid outward through the screen will tend to cleanse the screen by washing away the solid particles, muds, etc., that may have accumulated on the outside of the screen, and also will dissolve or liquefy many of the viscous or semi-viscous products ofthe well, such as paraflin, etc., that may have clogged the screen and retarded, or prevented, the free flow of liquid therethrough.

Should the pressure in the well outside the casing 'decrease sufliciently from any cause, the hot water ejected would, of course, liberate large quantities of steam which would penetrate and condense in the crevices in thestrata and rapidly warm same; and a similar result would be secured as soon as forced, by pressure, below the top of the screen, or perforations, in the well, at which openings the side of the well casing and permeate and condense in the earth strata,

rapidly warming the same.

When the oil again flows freely, the valve 15 is opened and process of ejecting the liquid is re's'i ed.

This heating and cleaning of the screen and oil strata may be performed as often as found necessary.

Generally oil wells, especially when they need cleaning, or flow slowly, or not at all, contain more or less water or oil, or both, in the lower part of the casing; and for the purpose of flushing the stratawith heated liquid, and washing the strainer by forcing this heated liquid out therethrough, this normal source of liquid supply will ordinarily suffice. But, under certain conditions, it may be desirable to furnish more liquid, or even a complete supply of water to the well chamber to carry the heat back into the well strata; and this can be done by connecting either the pipe 4 or the pipe 14 to any suitable source of water or oil supply. It is preferable to-use crude oi for. the pur-, pose, as it has substantially-the same specific gravity as the liquid in the well. Thus liquid may be pumped or' allowed to-run by gravity into the well until it rises to the required height in the casing. Then this liquid may be heated, generating steam or other gaseous pressure above same, as before described, and the heated liquid may be forced by. this pressure downthe casing and out through the screen in thesame manner .as

, if the liquid had flowed in from the strata of earth in the usual way.

Itmay be desired, in certain cases, to raise or lower the inlet 48 of the ejector to suit varying conditions of the flow of liquid in the well, such, for instance, as are occasioned by the lowering of the natural static head of the liquid in the well. This may be accomplished in various ways, for'instance, by

using the derrick arrangement, not shown, employed in constructing the well and by attaching the hoist .50 to the inner pipe 11, and thereby raising or lowering said pipe.

While I have shown in this divisional application the complete apparatus described and claimed in my Patent #1,140,982, aforesaid, it will be obvious that this cleansing of the well and its screen by generating pressure therein is not necessarily limited to apparatus in which the liquid is lifted from the well by an ejector; and the herein described process -may be used with other from the well either by the natural pressure,

forms of apparatus, in which the oil escapes Or is pumpedor lifted out by other means than the ejector herein shown, but I prefer to use, in carrying out the herein described process, the apparatus described in my patent aforesaid for the reason, primarily, that the same apparatus which provides the heat and gaseous pressure for operating the ejector,- also provides the heat and gaseous pressure for operating the process hereinafter claimed. While the two processes are in a sense independent of each other, it being impracticable with the same apparatus to carry out the two processes simultaneously, at the same time the processes are closely related in-that the flow of liquid into the well is promoted at one step, and after this flow becomes continuous the same apparatus will generate the gaseous-pressure required to lift the liquid out of the well; but I do not mean to limitmyself to any particular apparatus for carrying out the herein described process.

While I have shown herein the preferred form of apparatus, and have described the method of operating the same, it will be obvious that various modifications, both in the apparatus and in the mode of operation, may be employed which could be used without departing from the spirit of my invention, and I do not intend to limit myself to details of construction and operation, ex-

cept such as are specifically set forth in the claims. Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is the lower end of said casing to generate j therefrom gaseous pressure in said casing, which rising 1n sald caslng above sald heated liquid will force part of the liquid so heated back throughsaid screen into the oil-bearing strata, -thereby warming same and thinning the oil, and incidentally cleansing said screen, in then relieving said pressure and allowing the wellto resume its flow, and finally lifting the liquid flowing from the well into the bottom of said casing by means of .gaseous pressure flowing through said injector, said gaseous pressure being generated by heating part of the liquid contained in said casing, substantially as described. I

' 2. The method of operating oil wells provided with a gas-tight casing having a closed top and a screen in the lower portion thereof, and a central delivery pipevand an injector therein inclosed in said casing, with means for closlng said plpe, which consists in applying suflicient heat to the liquid in 1 the lower end of said casing to generate therefrom gaseous pressure in .said casing, which rising in said casing above said heated liquid will force part of the liquid so heated back through said screen into the oil-bearing strata, thereby warming same and thinning the oil, and incidentally cleansing said screen, and in then relieving said pressure and allowing the well to re- 'sume its flow, and in repeating said operation of heating the liquid in the casing, generating pressure, and causing said pressure to discharge the liquid f from said casing back into the oil-bearing strata until the latter are sufliciently warmed to secure the proper flow of oil therefrom, and finally lifting the liquid flowing from the well into the bottom of said casing by means of gaseous pressure flowing through said injector, said gaseous pressure being generated by heating part of the liquid contained in said 7 casing, substantially as described. I

3; The method of cleansing oil wells provided with a gas-tight casing having open ings in the lower portion thereof, and a closed top, and means for supplying liquid liquid through said top to the interior of said casing, in applying suflicient heat to the closed top, and means for supplying liquid therethrough, which consists in supplying liquid through said top to the interior of said casing, and in applying sufiicient heat to the liquid in the lower end of said'casing to enerate therefrom gaseous pressure in em above said heated liquid will force part of the liquid so heated, and also part of the steam and other. gases so generated, back 7 into the oil-bearing strata, thereby warming same and thinning the oil, and in then relieving said pressure and allowing therethrough; which consists in supplying.

-therethrough which consists casing, which rising in said casingthe well to resume its flow, and in repeating said operation of supplying fresh liquid through the top of said casing, heating the liquid in'the casing, generating pressure, and causing said pressure to discharge the liquid from said casing, and also part of the steam and other gases so generated, back into the oil-bearing strata until the latter are sufliciently warmed to secure the proper flow of oil therefrom, substantially. as described. 1

5. The method of operating oil wells provided with a gas-tight casing having openings in the lower portion thereof, and a closed top, and means for supplying liquid liquid through said top to the interior of said casing in applying sufiicient heat to the liquid in the lower end of said casing to generate therefrom gaseous pressure in said casing, which rising in said casing above said heated liquid will force part of the liquid so heated, and also part of the steam and other gases so generated, back into the oil-bearing strata, thereby warming same and thinning the oil, and in then relieving said pressure and allowing the well to resume its flow, and finally lifting the liquid pp y from said casing after the well resumes its flow, by an injector operated by gas pressure generated from the liquid that has flowed into the well, substantially as described. v I In testimony whereof, I afiix my signature.

WILLIAM DANIEL HUFF.

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