US2781099A

US2781099A - Oil well tool

Info

Publication number: US2781099A
Application number: US421849A
Authority: US
Inventors: John D Chesnut
Original assignee: Aerojet General Corp
Current assignee: Aerojet Rocketdyne Inc
Priority date: 1954-04-08
Filing date: 1954-04-08
Publication date: 1957-02-12
Anticipated expiration: 1974-02-12

Description

Feb 12, 1957 J. DICHESNUT 2,781,099

OIL WELL TOOL 2 Sheets-Sheet 1 Filed April 8, 1954 iNVENTOR. JOHN l2 Clem/v07 Feb. 12, 1957 J. D. CHESNUT 2,781,099

OIL. WELL TOOL Filed April 8, 1954 2 Sheets-Sheet 2 INVENTOR. 7 .JOHN D Cms's/vur United States Fatent 01L WELL TooL Application April 8, 1954, Serial No. 421,849

7 Claims. (Cl. 166-63) This invention relates to dumping and jetting devices for injecting fluids into wells.

An object of the invention is to provide a pressure operated device for the jetting or dumping action.

In the operation of deep wells, particularly oil wells, it is often desired to inject liquids into the formation around the bottom or lower part of the well. For ex-j ample, acid is often injected into limestone formations; or other types of cleaning liquids may be injected to clean out around the bottom of the well. Since the pressure at the bottom of a deep well is often very high, the liquid must be subjected to high enough pressure to eject it.

The invention is carried out by provision in a compact unit of a fluid vaporizing chamber into which is placed the liquid to be injected. A feature of the invention resides in a fuel container in heat-transfer relation ship with a vaporizable liquid. A self-combustible and preferably non-gassing fuel is placed within the fuel con tainer, along with igniter means. By providing such a fuel container the combustion reaction is isolated from the pressure of the volatilized liquid, and also from wellsubmergence pressures. Therefore these pressures can not adversely aifect the combustion reaction. Heat from the reaction of the fuel vaporizes at least some of the liquid to create suflicient pressure to drive fluid out of the chamber and through the well casing against the high pressure which exists there.

An optional feature resides in providing the carrier with en eductor tube which interconnects with the conduit means and opens in the vaporizing chamber above the liquid level therein. Only vapors may then escape from the vaporizing chamber into the well.

These and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, of which:

Fig. 1 is a side elevation, partly in cross-section, of a dumping device according to the invention;

Fig. 2 is a cross-section taken at line 2-2 of Fig. l; and

Fig. 3 is a side elevation, partly in cross-section, of another device according to the invention.

Referring now to the drawings, Fig. 1 shows a device for injecting fluids into a well casing 11. The device is suspended by a line 12 which is payed out from the surface. The device comprises a carrier or housing having a generally cylindrical wall 13 closed at the top and bottom by

plugs

14 and 15 respectively. A plate 16 extends across the inside of the housing so as to divide the interior into two chambers, an upper vaporizing chamber 17, and a lower dumping chamber 18.

Plate 16 has passages 19 leading therethrough which interconnect the two chambers. A spring-loaded check valve 20 permits flow through passages 19 from chamber 17 into chamber 18, but prevents flow in a reverse direction. A raised boss 21 with external threads thereon extends into vaporizing chamber 17 so as to form a base for a heating element 22. This heating element comprises a dome 23 which is threaded to the boss to create a rigid fuel container strong enough to resist the ambient pressure in the well and also pressure developed by volatilizing liquids which may contact it. Within the dome is placed a fuel, of a type which is self combustible, that is, which burns or creates heat without the need of an external oxygen source such as the air. The fuel container thus entirely surrounds the fuel and isolates it from surrounding pressures. The preferable type of reactants for fuel are those which produce heat without emitting substantial gas. A satisfactory combination of materials which react in such a manner is a stoichiometric and intimate mixture of powdered aluminum and finely divided potassium perchlorate. This mixture reacts according to the following equation:

A firing squib 25 is disposed inside the heating element, and an electric lead wire 26 connects with the squib and passes to the outside of the device through a tube 27. Tube 27 passes through the dome 23, the upper plug 14, a stufling box 28, and a threaded stopper 29. The lead wire 26 is connected with a source of electric current (not shown). A quantity .of vaporizable liquid fluid 30 to be dumped into the well is placed in the vaporizing chamber 17.

The dumping chamber 18 may be of about the same diameter as chamber 17, as shown, or it may simply be a conduit of sufiicient size to transmit the fluid to the well. This chamber interconnects with the well through ports 31 in the side of the housing 13.

Fig. 3 shows an embodiment of the invention which is adapted to discharge only vapors. It is substantially the same as the device shown in Fig. 1, having a casing 40, an upper plug 41, lower plug 42, and plate 43. A

heating element similar to element 23 is mounted on the plate and has a firing squib 45 therein.

The plate divides the inside of the carrier into a vaporizing chamber 46 which is substantially filled with a vaporizable liquid 47 for injection into the well. An eductor tube 48 passes through the plate and has an overhanging crook 48a above the surface of the liquid at its upper end. The eductor tube leads downward to the discharge chamber 49. A check valve 50 is mounted between the two chambers so as to permit only unidirectional flow from the vaporizing chamber to the discharge chamber. If desired, the eductor tube may discharge directly from the upper chamber into the well. Ports 52 are drilled in the side of casing 40.

Holes 53' are shown in the wall of the well casing in Figs. 1 and 3. Holes of this type are often created by perforators so that the fluids can enter the well casing. Fluids discharged from the device of this invention may also pass through the well casing via these holes. Such holes might also be provided in the form of a screen.

The operation of these dumping devices will now be described. The unit shown in Fig. l is lowered to the desired depth by line 12. Then an electric current is passed through lead Wires 26 to ignite the squib 25. The squib heats the mixture of aluminum and potassium perchlorate to a temperature at which they undergo a selfsustained exothermic reaction. This reaction, being in an isolated part of the system, is entirely independent of ambient well conditions. The heat from this reaction passes through the dome 23 and vaporizes at least some of the liquid 30, since the liquid makes direct contact with the dome.v This vapor creates a pressure in the vaporizing chamber. As soon as the pressure overcomes the force of the check valve 20, fluid begins to flow into the discharge chamber 18 and then through ports 31 into the well. The check valve prevents backflow of liquids from It will be appreciated that the combustion of the fuel' is independent of the pressures which surround the fuel container. When non-gassing. fuels are used, the reaction is also substantially independent of pressure within 'the fuel container which'may be developed in the combustion process. 7 7 r Y The fluid 30 will generaliy'be vaporizable liquid, and be dumped from the chamber 17 while still at least partly in the liquidstate. It is also possible to provide a mixture of liquids, one having a relatively low, and the other a relatively. high, boiling point, so that the liquid with the lower boiling point is vaporized first, and expels the other liquidin the liquid state. Ineither event, the means for injecting the fluid into the well is the pressure of the vaporin the vaporizing chamber.

While the drawing shows a hole 53 in the casing aligned with a port 31 this is only a desirable coincidence, and

not a necessary condition for the successful operation ofv the device. More or fewer ports 31 may be provided as desired.

sure will be built up in the upper part of vaporizing ehamber.46 and eductor tube 48 to overcome the resistance of check-valve 50. The vapor then is ejected from the tube into the lower chamber 49, and escapes through ports 52 into the casing 51. The eductor tube stands above the liquid level, and therefore only vapors will enter it to be discharged into the well.

As in the embodiment of- Fig. 1, the lower chamber may have any desired size, depending on the amountof vapor expansion desired in that chamber.

This invention provides a dumping or jetting device in which the combustion process'for vaporizing the liquid to be dumped'is entirely independent of vapor pressure and of well submergence pressures. Prior devices of this nature have exposed the reactions to such pressures, and it has been found that the combustion process has deteriorated. It will also be appreciated that the combustion process is free of self-generated pressures when a non-gassing mixture is used. When no gas is given off, an increase in pressure in the heating element does not result in an appreciable rise in pressure, and thus the combustion reaction is not deteriorated by pressures within orwithout the heating element.

There are other satisfactory reacting substances in addition to those shown herein, the combination described being given as a single example. The invention is not to be limited to the illustrations shown in the drawings and described in the description, these being given by way of example and not of limitation, but onlyin accordance with the scope of the appended claims.

I claim: Y 1. Apparatus for dumping fluids into well casings comrising a carrier having 'a'vaporizing' chambena heating element comprising a rigid fuel" container -in the vaporizing chamber and a selfcombustible fuel in the fuel clontainer, said fuel container entirely surrounding the fuel and isolating it from. surrounding pressures,,and exhaust means from the vaporizing chamber communicating with the outside of the carrier, whereby fluid to be dumped may be placed'in said vaporizing chamber in contact the heating element, and heat from'the heating element resulting from combustion of the fuel heats the fluid 2. Apparatus for dumping fluids into well casings comprising a carrier having a vaporizing chamber, a heating element comprising a rigid fuel container'in the vaporizing chamber and a self combustible fuel in the fuel container, said fuel container entirely surrounding the fuel and isolating it from surrounding pressures, the carrier having an exhaust passage intercommunicating the lower part of the vaporizing chamber and the outside of the carrier, and check valve means in the exhaust passage,

whereby fluid 'to be dumped may beplacjed inside, said 3. Apparatus according to claim 2 in which the self combustiblefuel is a substantially.stoiehiometric mixture of metallic aluminum and potassiumlperchlorate, whereby the combustion of the fuel is substantially independent of pressures within the fuel container which are developed by the combustionreaction. V V

4. Apparatus for dumping fluids into well casings comprising a carrier having a vaporizing chamber, an exhaust chamber, an exhaust passageintercommunicating the two 1 chambers, and a portfrorn the exhaust chamber to the outside of the carrier, a heating element in the vaporizing chamber. comprising va rigid fuel container and aselfcombustible fuel in the fuel container, said fuel coritainer entirely surrounding the fuel and isolating it froin surrounding pressures, auda check valve in: the exhaust passage for permitting only unidirectional flow through the said exhaust passage, said unidirectional flow passing from the vaporizing chamber into the exhaust chamber, whereby fluid. to be dumped may be placed inside said vaporizing chamber in contact with the heating element, andheat from the heating element resulting from cornbustion of. the fuel vaporizes at least a part of the fluid, 7

thereby creating a vapor pressure which expels fluid from the vaporizing chamber through the exhaust passage, exhaust chamber, and port into the well casing, the combustion of the fuel occurring independentlyo'f pressures surthereby creating a vapor pressure which expels the vaporizing chamber through the exhaust rneans into V the well casing, the combustion "of the fuel occurring use pendently of pressures surrounding the heating element.

roundingthe heating element.

5,. Apparatus according to claim 4 in which the fuel is a substantially stoichiometric mixture of Imetallic alu:

minum and potassium perchlorate, whereby the combus-r tion of the fuel is substantially independento'f pressures,

within the fuel container which combustion reaction. a

6. Apparatus according to claim 4 in which the exhaust passage comprises an eductor tube having its openare developed by the ing' in the vaporizin'g chamber so disposed and arranged a ,vapor andigas is dumped during said substantial portion of said operation, the eductor -tube opcning being dis posed above the surface .of liquid in said vaporizing chamber; 7 7 7. Apparatus according to claim'6 in' which a check valve for permitting only unidirectional flow fromthe vaporizing chamber is placed in the educ'tor tube No references cited.