US3190357A

US3190357A - Well tool and method of using same

Info

Publication number: US3190357A
Application number: US192120A
Authority: US
Inventors: Rufus P Kirk
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-05-03
Filing date: 1962-05-03
Publication date: 1965-06-22
Anticipated expiration: 1982-06-22

Description

June 22, 1965 R. P. KIRK WELL TOOL AND METHOD 0F USING SAME 3 Sheets-Sheet 1 iledk May 5, 1962 -w u .a I=. Z lr r r 6 M 6 INVENTOR.

BY/7 ale/ 4 Y M June 22, 1965 Filed May 5, 1962 R. P. KIRK WELL TOOL AND METHOD OF USING SAME 5 Sheets-Sheet 2 /r/fUJ P. /f/r/f INVENTOR.

June 22, 1965 Filed May E, 1962 R. P. KIRK WELL TOOL AND METHOD OF USING SAME 5 Sheets-Sheet 3 INVEN TOR.

3,190,357 WELL TOUL AND METHD 9E' USING SAW Rufus P. Kirk, dessa, Tex.

(1417 Sherwood Lane, @Mahoma City, Okla.) Fiied May 3, 1962, Ser. No. 192,12) 15 `Claims.. (Cl. 16S-44) This invention relates to new and useful improvements in well tools and methods of using same.

An object of this invention is to provide a new and improved valve for a well pipe which is open to provide for the unloading of mud or other fluid in the pipe and which is automatically closed to provide for the tlow of the oil or other well fluid after the unloading.

An important object of this invention is to provide a new and improved method for displacing iiuid in a casing annulus and well tubing by circulating a gas or a liquid lighter than the fluid to be displaced, then closing off such circulation, and producing oil or other well iuid through the tubing.

Another object of this invention is to provide a new and improved method and valve which is adapted to be used in conjunction with one or more gas lift valves for improving the operation of the gas lift valves by providing a lower liquid level in the casing annulus than is normally attained in the absence of such valve.

A particular object of this invention is to provide a new and improved valve adapted to be positioned in a well tubing longitudinally below a lateral opening in the tubing, said valve having a frangible closure which is adapted to be fractured upon an upward movement of the valve in the tubing, whereby the valve closes olf the flow through said lateral opening and opens iiow from said tubing through said valve.

A further object of this invention is to provide a new and improved method and apparatus wherein circulation between a casing annulus and an opening in a well tubing is effected, then such circulation is stopped by closing such opening, and thereafter such opening is opened again by a well tool to permit a killing of the well, further circulation, or similar operations.

The preferred embodiment of this invention will be described hereinafter, together With other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIG. 1 is a schematic view illustrating the first part of the method of this invention wherein the gas is being introduced into the casing annulus for displacing the mud in the annulus and the tubing;

FIG. 2 is a view similar to FG. 1, but showing a further step in the method of `this invention wherein substantially all of the mud in the casing annulus and tubing have been displaced by the gas;

FIG. 3 is a viewsimilar to FIG. 1 and FIG. 2, but illustrating the valve of this invention in a closed position for closing off the lateral opening between the tubing and the casing annulus and the subsequent production of oil or well uid through the tubing to the surface;

FIG. 4 is a schematic view illustrating a modified form of the method of this invention wherein gas lift valves are employed, and wherein a first stage of such method is illustrated with the gas injected into the casing annulus and operating the upper gas lift valve;

FIG. 5 is a view similar to FIG. 4, but illustrating the modified form of the invention of FIG. 4 wherein the next phase is indicated by the displacement of the drilling 3,l9,357 Patented June 22, 1965 mud or other fluid in the annulus and tubing with gas injected from the surface;

FIG. 6 is a view similar to FIGS. 4 and 5 and illustrates the next phase of the method of such modified form of the invention, wherein the lateral opening in the well pipe or tubing is closed by the valve and the gas lift operations are performed by the predetermined gas pressure inthe casing annulus which is introduced through the gas lift valves;

FIG. 7 is a vertical sectional view of the preferred form of the valve of this invention, shown in the position Ifor closing off flow through the valve body while permitting flow through the lateral opening of the well pipe or tubing; and

FIG. 8 is a view similar to FIG. 7, but illustrating the valve in the position closing the lateral port of the Well pipe or tubing and providing an opening through the valve body for the flow of oil or other well fluid upwardly through the valve body and into the tubing or pipe thereabove.

In the drawings, the letter C designates a well casing which is of conventional construction and which has a well pipe or tubing T therein, with a casing annulus A therebetween. The well pipe or tubing T has a lateral opening or openings 10 formed therein, the opening and closing of which is controlled by a valve V, the details of which will be explained hereinafter. A packer P of conventional construction is disposed in the casing annulus A below the opening or openings 1t). Briefly, in carrying out the method of this invention using the valve V of this invention, gas or other iiuid G is introduced into the upper end of the casing C so as to force the drilling mud M or other well fluid downwardly in the annulus A, through the opening or openings 1li and upwardly in the well pipe or tubing T. Such circulation of the gas G continues until a pressure differential is developed across the valve V within the tubing T which is sufficient to move the valve V automatically to a closed position (FIG. 3). When the valve V is in the closed position, the well fluid W, generally oil, is produced through the pipe or tubing T for discharge at the surface S, or through any other suitable well head equipment. Also, as will be explained in connection with FIGS. 4-6, the method of this invention may be employed in conjunction with gas lift valves on the well pipe or tubing T. Furthermore, if it is necessary or desirable to open the valve V again after it has been moved to the closed position, such opening can be accomplished by the use of a wire line tool sothat the well can be killed with mud or the like, or othersimilar well operations performed.

Considering now the details of the valve V of this invention, which are shown in FIGS. 7 and 8, such valve V includes a tubular pipe section 12 having the openings 10 formed laterally therethrough. Such section 12 has an adapter 14 threaded or otherwise secured to its upper end and a second adapter 15 threaded or otherwise connected to its lower end. The adapter 14 is connected to a pipe section 16 which extends on upwardly with' the rest of the pipe or tubing T to the surface S. The adapter 15 connects with a tubing section 17 by means of threads or any other suitable connetcing means so that the tubing string T continues on down below the valve V.

The valve V includes a longitudinally movable valve body 20 which has an upper bore 20a and a lower bore 2Gb. The bores 20a and Ztib are of the same internal diameter and it is to be noted that the thickness of the valve body 20 extending from such bores 20a and 20h outwardly, together with the thickness of the valve section 12, are approximately the same as the thicknes of the adapters 14 and 1S and the

normal tubing sections

16 and 17. Therefore, the valve V of this invention provides a full open bore, as will be enlarging the external diameter of the tubing string T. In circumstances where the enlargement of the tubing more fully explained, without string at the valve V is not undesirable, the thicknesses ofv the valve section 12 and thek body 20 may be increased.

The valve body 20 has a lower yannular extension 29C' which ts into an annular slot a atV the upper end of' the adapter 15. lSuitable shearA pins 25 extend through the i valve body 20, as will be more evident hereinafter. Suita,

ble lexternal seal rings 26 at the lower end and 27 Vat the upper end are provided for sealing on both the upper and lower sides of the openings 10 when the valve bodyv isin the positionfor closing such openings 10 (FIG. 8). f v

The body 20 is provided with an annular external recess 20d above the O-rings 27, which recess 20direceive's a split metallic lock ring 30. Such 'ring 30 is confined in a compressed condition when the valve bodyy20 is in the lower position shown in FIG. 7, but is expanded by its own resilience to the position shown in FIG. 8 when the valve body 20 has moved upwardly to closejthe openings or ports 10. Such lock ring 30 retainsthevalve body 20 in the upper position of FIG. 8 even after the well fluid pressure differential has ceased to act in an upward direction on the body 20. A seal ring 28 'which is alsoA of rubber and preferably an,O-ring,is located above the lock ring 30 to reduce the Vamount of corrosive fluids' which might otherwise reach the lock ring30.

The valve body 20 has an annular lateral shoulder 20eV 'Y formed above the bore 20a for receiving a closure disk'31.

The peripheral edges of the disk 31 are in contact with body 20 as shown in FIG. 7. YThe closurefdisk orl plate 31 may be made of any suitableffrangible material such as tempered glass or ceramic material. The material must' be sufficiently strong to withstand the pressureA differential acting thereacross, but at the same time it'must shatter fluid.

Vbelow the bore`12a. 31 are indicated by the designation 31a in FIG. 8 to indif for the ow'of fluid `through the valve body or sleeve 20 to the upper portion of the tubing T. .The lock ring 30 expands to the position shown in FIG. 8 within the enlarged diameter 12a to hold or lock the body or sleeve 20 in the upper position, bythe frictional engagement with the internal surface of the bore 12a, and also by a contact with the inclined annular surface 12b formed The fragments ofk the closure disk cate that suchfragments 31a'are moving with'the well It should be pointed out that the upper surface i31b (FIG. 7.) of the disk 31 is preferably coated with a layer of rubber orsimilar material whichfwill resist Vabrasion or Sandblasting action caused by-thev circulation of mud or other fluid prior to the breaking-,of the disk 31. A similar coating 31C mayr also be providedon the lower Y surface of thevdiskl, although it-'generally is not as desirable or necessary. l i v y v -In carrying out the method of this inventionas particularly illustrated in FIGS; 1 3, the tubing T is initially positioned-in the casing C with Vthe packer P inV position as shown in FIG. l. The valve V is loweredr with the tubing string `T and is Ysecured in its lower position (FIG.` 7) byl means ofthe. shear pins 25. f The shear pins are set atthe-time of assembly so as to shearv or sever i the body 20 andthe closure plate 31.

vao

The pins 25 are of such strength that the pressure of the oil or other well fluidW belowr the valve V, minus'the pressurerof the gas G introducedr into the casing annulus A will sever'br shear suchpins 25.` In order to provide some flexibility in the amount of force necessary toshear the pins V25, they can'berrnade so that they will shear at the pressure kof theV oil or well uid Then, if the gas pressured G is too high so that thepressure differential between the well uid and the gas is not suiiicient to sever .the pins 25, the ygas pressure can be bled olf to as low to small .pieces whenffractured to open flow throughthe valve body 20,7as' will be more fully explained. l In order to provide for the movement of the valvebody 20 downwardly from the positionY closing'the Aports 10" as shown in FIG. 8y to the position opening the ports 10 as shown in FIG. 7, it is desirable to provide a central bore section 20]c of an increased internal diameter as compared to the bore sections 20a and 20h. Such en'- larged bore section 20jc provides for a lower lateral shoulder 20g which is adapted to be contacted byv a con! y thereto as shown in FIG. 2 before thepins 25v shear. Such ventional wire line operated well tool shown" in dotted lines and indicated by the letter R in FIG., 8. e

The valve section 12 is formed with an enlarged internal diameter section 12av at its upper end so that the-split ex-Y pansible ring may` expand outwardly as shown in FIG. 8 to hold or lock the sleeve 20iri` the upper position. v

VThe adapter 14 has a plurality ofv sharp pointed pro- Jecnons 14a which are adapted to contact the closure diskV or plate 31-as the valve body or-sleeve 20 moves upwardly by the action of the fluid pressureY differential withinf the Well. Such projections 14a cause a fracturing ofY as atmospheric pressurein order to create an adequate pressure vdifferential across the body 20 and the closure 31.

In any event,'after the tubing T has been positioned as shown in' FIG. yl with theY packer P below the lateral openings 10,l the gas Gy or otherfluid lighter in density than the mud M is introduced at the upperend of the 'c annulus Av through any suitable well head equipment schematically indicated at C. Such gas G displaces the mud downwardly in the annulus-A through the lateral openings 10 and then `upwardly in the tubing T for d ischarge through the surface outlet S; Since the mud is of a greater density than the gaslor other'fluid G, the pressure differential acting across-the valve body 20 and the closure plate 31 is smaller with the'mudnthan with they gas. Preferably, theV gas G fully displa'ces themud M, or atleast the gas/G reaches the level G or one similar pins 25 shear automaticallyr when the pressuref differential actingacross ythe valve Vbody 21V/is sufficient to sever the pins 25. The valve body 20.v is then moved upwardly by the pressure differentiall so that the closure plate or disk 31 hits the projectionsla with a blow orl impact sufficient to crack vor shatter the material of the plate or disk; 31 into small particles 31411116. 8),. vTher well fluid is thus capable of flowing upwardly through the bore of the body 20 intfo'the tubing T thereabove. Inl the usual case, the particles 31a are carried upwardly with the well fluid and are discharged at the upper.v surface outletS.

When the valve body 20. has` moved kupwardly to the closed position, the seal rings 2,6.and 27 span the openings 10. The 'gas G is thus confined in the annulus A, and preferably the inlet line, C is `closed with a valve or other suitable means'X (FIG. 3).

- Y Thus,.. with the method of this invention asY described above and as illustrated in'FIGS. 1-3., the mud or other well fluid-is displaced from the annulus and the tubing after the packer P is set, causing the well to iiow with the oil or other well fluid without the use of swabbing or wire line operations inside the tubing. Also, the dangers inherent in unloading a well before setting the packer are eliminated with this invention.

The gas G is preferably nitrogen or methane, but other gases may be used. Also, a light density uid such as water, which has a lighter density than the usual mud M in the Well, may be used in place of the gas G. So long as the gas or other fluid G has a light enough density to cause a suicient unloading of the mud M to reduce the pressure above the valve V so as to develop a pressure differential across the valve V sufficient to sever the shear pins 25, it will suffice for the purpose of this invention.

In the form of the invention shown in FIGS. 4-6, gas is used as the primary unloading liuid since gas lift valves indicated schematically at F-1, F-2 and F-3 are preferably used with such form of the invention. It will be understood that although only three gas lift valves are illustrated in FIGS. 4-6, additional valves may be ernployed, depending upon the usual spacing and production requirements. Even though the gas lift valves are employed in the modified form of the invention shown in FIGS. 4-6, the method as described in connection with FIGS. 1-3, and the operation of the valve V are basically the same. Thus, the gas G or other uid which is lighter than the mud M is introduced .at the well head connection C to the annulus A for unloading or displacing the mud M from the annulus A and the tubing T. The valve V is in the lower position wherein the ports are opened during such circulating or unloading of the mud M from the tubing T. During such unloading, the gas lift valves may function to introduce or inject gas into the tubing T before the level of the gas G has reached the lateral openings or ports 10, but such action of the gas lift valves is not necessary until after the gas G has completely unloaded the annulus A and has at least partially unloaded the tubing T.

When the pressure differential acting across the valve body and the closure disk or plate 31 reaches the predetermined value necessary to shear the pins 25, the valve body 20 moves upwardly to the position shown in FIG. 8 and closes the ports 10.

With the valve V in the closed position, closing the ports 10 and with the disk 31 shattered to allow the well fluid W to flow upwardly through the body 20 and into the tubing T, the usual production techniques with the gas lift valves are then employed. However, the gas lift valves operate more satisfactorily with the present method and apparatus because the presence of the gas at the point below the lowest of the gas lift valves is assured with the present invention. The present method, when used in con junction with the gas lift valves, makes it possible to work the lowest gas lift valve which is set to open at the gas pressure in the annulus A, and minimizes problems in gas lift production such as improper valve spacing, emulsion formation, and differentials in liquid levels in the tubing and annulus. The pressure of the gas G in the annulus A is maintained for continuous ow lifting or controlled for intermittent or slug lifting through the inlet valve X or other suitable means so that the gas injection into the tubing T is thereby controlled after the valve V has moved to the position shown in FIG. 6.

Other advantages in addition to those enumerated above will occur to those skilled in the art in connection with the use of the present invention in conjunction with the gas lift valves as shown in FIGS. 4-6. It will also be appreciated that this invention may be used in dual production lines.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, `as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. A valve adapted to be mounted in a well pipe having a lateral opening therethrough, comprising:

(a) a tubular valve body mounted in said well pipe for longitudinal movement relative to said pipe,

(b) closure means carried by said body for closing off fluid flow from said pipe through said valve body,

(c) retaining means releasably retaining said valve body in an open position in said pipe permitting uid ow through said lateral opening,

(d) said retaining means being releasable upon the application of a predetermined fluid pressure differential acting on said closure means for moving said body longitudinally in said pipe to close said lateral opening, and

(e) opening means for engaging said closure means upon the longitudinal movement of said valve body for opening said closure means and permitting iow through said body from said pipe.

2. The structure set forth in claim 1, wherein (a) said closure means is frangible into relatively small pieces, and

(b) said opening means for engaging said closure means includes means for fracturing said closure means upon the longitudinal movement of said valve bodyrelative to said pipe.

3. A valve adapted to be mounted in a well pipe having a lateral opening therethrough, comprising:

(b) closure means carried by said body for closing off iiuid dow from said pipe through said valve body,

(c) retaining means releasably retaining said valve body in a position permitting liuid dow through said lateral opening,

(d) said retaining means being releasable upon the application of a predetermined fluid pressure differential acting on said closure means of said valve body for moving said body longitudinally in said pipe to close said lateral opening, and

(e) means for opening said closure means upon the longitudinal movement of the valve body for permiting fluid ow in the well pipe.

4. The structure set forth in claim 1, wherein said retaining means is .a shear pin connecting said valve body to said pipe and adapted to shear when said predetermined fluid pressure differential is developed.

5. The structure set forth in claim 3, wherein said retaining means is a shear pin connecting said valve body to said pipe and adapted to shear when said predetermined fluid pressure differential is developed.

6. The structure set forth in claim 3, including seal means between said valve body and said well pipe for inhibiting fluid ow downwardly around said valve body when said valve body is in said open position, whereby fluid may be circulated between the interior yand exterior of said pipe through said lateral opening above said seal means and said closure means.

7. In combination with a well pipe in a well casing wherein the annulus between the casing and the pipe is packed olf with a packer, and wherein the pipe has a lateral opening therethrough above the packer, the improvement residing in a valve, comprising:

(b) closure means carried by said body for closing off fluid iiow from said pipe through said valve body,

(c) retaining means releasably retaining said valve body in a position permitting uid flow through said lateral opening,

(d) said retaining means being releasable upon the application of la predetermined uid pressure differen-` tial acting on said closure means of said valve body 7 for moving said body longitudinally in said pipetov close said lateral opening, and (e) means for opening said closure means upon the longitudinal movement of the valve body for permitting uid flow in the well pipe. v 8. In combination with `a well pipe in a well casing wherein the annulus between the casing and the pipe is packed o with a packer, and wherein the pipe has a later-al opening therethrough above the packer, the irnprovement residing in -a lv-alve, comprising:

(a) a tubular valve body mounted in said well pipe for longitudinalmovement relative to said pipe, (b) closure means carried by said body for closing oft iiuid ilow from said pipe through said valve body,

(c) retain-ing means releas-ably retaining said valve` body in an open position in said pipe permitting fluid iiow through said 'lateral opening,

(d) said retaining means being releasable upon the application of a predetermined fluid pressure differentialncting on said closure means for movin-gsai-d (a) closing o." fluid tlow downwardly through the tubing below the later-al opening, t

(b) circulating a iluid downY the casing annulus and through said lateral opening lfor now upwardly in said tubing to thereby displace the fluid previously in the annulus and tubing with a lighter density fluid,

(c) developing a predetermined `iluid pressure differential across the closed oi portion of the tubing sui-v cient to effect an opening of the tubing, and (d) closing said lateral opening in response to said iiuidgpressure differential to discontinuelcirculation trom the annulus to the tubing wlhile enabling Well 'fluid .to be produced through the tubing.

10. Incombination with a well pipe in a well casing wherein the :annulus between the casing and the pipe is packed off with laY packer, 'wherein a plurality of longitudinally spaced gas lift valves are mounted on the well pipe in the annulus, and wherein the pipe has a lateral opening at a point below said gas lift valves and above the packer, the improvement residing in a valve, oom-k prising:

(a) a tubular valve body mounted in said well pipe'for longitudinal movement relative to said pipe, (b) closure means carried by said body tor clos-ing oit iiuid tlow from said pipe through said valve body, (c),retaining means .releasabily retaining said |valve body in a position permitting fluid ilow through said lateral opening,

(d) said retaining means being releasableupon the application of la predetermined iluid pressure diiferen-- tial acting on lsaid closure means of said valve body for moving said body longitudinally in said pipe t close s-aid lateral opening, and t (e) means vfor' opening said'closure means upon the longitudinal movement Aof the valve body Ifor permitting uid flow in the well pipe.

11. E1n combination `with a well pipe in a well casing wherein the annulus, between the casing and the'pipe is packed oli with a packer, wherein a plurality of longitudinally spaced gas lift valves are mounted on the vwell pipe in the annulus, and wherein the pipe has a` lateral opening Vvat a point below said gas lift valvesvand above said packer", the improvementresiding ina valve, compris-ing;

(a) a tubular valve body mounted in said wall pipe for longitudinal movement relative to said pipe,

(b) t closure means carried by said bodyfor closing olf fluid ilow from said pipe throughsaid valve body,

(c) retaining means releasably. retaining said valve body inY an open position in said pipe permitting iluid flow through said,v lateral opening,

(d) ,said'retaining meansbeing releasable -upon the application of a predetermined fluid pressure differential acting on'said closurel means for moving said body longitudinally in said pipe to close said lateral opening, and v (e) opening means t'or engaging said closure means upon the longitudinal moi/'ementy of said valve body for opening said closure means Iand permitting llow through said body from said pipe.

i12. A method of producing well `fluid throughr a tubing in a well casing, wherein the annulus between the tubing and the casing is packed oit with a packer, wherein a plurality ot longitudinally spaced gas lift valves are mounted on the well pipe in the annulus, and wherein the pipe'has a later-al opening below said gas'lift valves and above the packer, comprising the steps of:v

(a) closing oit vfluid iiow downwardly through the tubing below the lateral opening,

(b) circulating a gas down the casing annulus and through said lateral opening for tlow upwardly in said tubing Yto thereby displace the gas previously in the annulus and tubing with a lighter :dens-ity gas,

(c) developing a predeterminedl fluid pressure differential across the closed ott portion ofthe tubing suil cient to eiect an opening of the tubing,

(d) thereaftervclosing said Vlateral opening in said tubing to discontinue the circulation ,from the annulus to the tubing, and

(e) then producing oil through said tubing.

'k 13. A method of producing well uid throughfa tubing in a -well easing, wherein the annulus between the tubing and the casing is packed oit with a packer, wherein a plurality of longitudinally spaced gas lift valves are mounted on the well pipe in the annulus, and wherein the pipe has a lateral opening below said ga-s lift val-ves land above the packer, comprising the steps of;

(a) closing off tluid flow downwardly through the tubing below the lateral opening,

l(b) :circula-ting a gas down Ithe casing annulus and through :said lateral opening tor flow upwardly in said tubing to thereby displace ythe gas previously in the :annulus and tubing with a lighter density gas,

(c) developingr a predetermined fluid pressure differential across the closed off portion of the tubing sufii- 1 'cient to effect an opening of the tubing,

(d) ythereafter closing said lateral opening in said tubing to discontinue the circulation from the annulus to the tubing, and Y (e) then producing oil through .said tubing while controllingtthe gas pressure in Said Lannulus for gas injection into s-aid well pipe through said gas lift valves to etect a gas lift ofthe oil. l

14. A valve adaptedto be mounted in a well pipe hav-v ing a lateral opening therethrough, comprising:v

l (a) a tubular valve body mounted insaid well pipe for longitudinal movementrelative to said pipe,.

(b) closure means carriedby said body for closing oit iluid ilow from said pipe through said yalve body,

(c) retaining means releasably retaining said ,-valve body in a position permit-ting duid ilow through said lat-eral opening,

(d) said retaining means being releasable upon the application of a predetermined uid 'pressure differential acting on said closure means of saidvalve body for moving said body longitudinally in said'pipe to close said lateral opening, Y

(e) means on said lbody engageable by a tool lowered E in said pipe for effecting a longitudinal movement of said body to `open said lateral opening, `and (f) means for opening said closure means upon the longitudinal movement of the valve body for permitting lluid ow in the well pipe.

15. A method of producing Well fluid `through a tubing in a Well casing, wherein the iannulus between the tubing and the `casing is picked yoff with `a packer and wherein the tubing has a lateral open-ing above the packer, comprising the steps of:

a) closing 01T uid flow downwardly through the tubing below the lateral opening,

(b) circulating :a uid down the casing annulus and through said later-a1 opening for flow upwardly in said tubing to thereby displace the uid previously in the annulus and tub-ing with a lighter density lluid,

(c) developing a predetermined duid pressure differential across the closed `off portion of the tubing sufficient :to eifect an opening of the tubing,

(d) thereafter closing said lateral opening in said tub- 2 ing to discontinue the circulation from the annulus to the tubing,

(e) then producing well iluid through vsaid tubing, and (if) subsequently again opening said lateral Opening for killing the well and similar operations.

References (Jited by the Examiner UNITED STATES PATENTS 7/25 5/30 lll/36 8/4() 1/43 2/44 9/60 2/62' 4/62 1/63 6/63 3/64 Arbon 166-45 X Sawyer 166-44 Wells 166-68 X Brown 166-224 Baylor 166-67 Lloyd 166-45 X Garrett 166-45 X Tausch 166-44 X Moller 166-224 Murr-ay 166-224 X Alley 166-224 X Graham 166-224 X CHARLES E. OCONNELL, Primary Examiner.

Claims

9. A METHOD OF PRODUCING WELL FLUID THROUGH A TUBING IN A WELL CASING, WHEREIN THE ANNULUS BETWEEN THE TUBING AND THE CASING IS PACKED OFF WITH A PACKER AND WHEREIN THE TUBING HAS A LATERAL OPENING ABOVE THE PACKER, COMPRISING THE STEPS OF: (A) CLOSING OFF FLUID FLOW DOWNWARDLY THROUGH THE TUBING BELOW THE LATERAL OPENING, (B) CIRCULATING A FLUID DOWN THE CASING ANNULUS AND THROUGH SAID LATERAL OPENING FOR FLOW UPWARDLY IN SAID TUBING TO THEREBY DISPLACE THE FLUID PREVIOUSLY IN THE ANNULUS AND TUBING WITH A LIGHTER DENSITY FLUID, (C) DEVELOPING A PREDETERMINED FLUID PRESSURE DIFFERENTIAL ACROSS THE CLOSED OFF PORTION OF THE TUBING SUFFICIENT TO EFFECT AN OPENING OF THE TUBING, AND (D) CLOSING SAID LATERAL OPENING IN RESPONSE TO SAID FLUID PRESSURE DIFFERENTAIL TO DISCONTINUE CIRCULATION FROM THE ANNULUS TO THE TUBING WHILE ENABLING WELL FLUID TO BE PRODUCED THROUGH THE TUBING.