US2649915A - Apparatus for treating wells - Google Patents

Description

2 Sheets-Sheet l x hh.

L A.. MILLER Y APPARATUS FOR TREATING WELLS Aug. 25, 1953- Filed Dec.. 5. 1946 IRA A.v MILLER INVENTOR.'

BY Z3/M Arme/vn Patented Aug. 25, 1953 APPARATUS FOR. TREATING WELLS Ira A. Miller, Dallas, Ilex., assignor to Otis AEngineering Corporation, Dallas, Tex., a corporation of Texas Application December 3, 1946Seral No. 713,695

(Cl. 16S-2) 8 Claims.

, -This-` invention relates to new and useful improvements in apparatus` for treating wells.

modern oil and `gas well production practice, it is becoming more frequently customary to install packers between the well ow conductor or tubing and thebore of the well or the Well casing, and tovinsert loading fluids, such as columns of water` or mud or the like, in the e annular-space between the well .tubing and casing above the packers to counterbalance ory exceed .the upwardgforce exerted against such packers by the highbottom hole uid pressures, and to prevent application of such high fluid pressures-to thewell casing,ltubing and surface connections. The pressure load of the column ofloading fluids the annular space is frequently considerably in excess of the well formation pressure, and 1 the differentiall pressure increases as the -well formation pressure declines. It would be possible, if an adequatelyl large and heavy `quantityl Yof loading fluids were introduced into the annu- V`lar space,to utilize these loading fluids to kill the well by providing ysuitable means just .above the packer for establishing communication be- -tween the-annular space and the bore of the ow conductor, whereby the loading fluids couldvbe admitted to the flow conductor where they would Vserveto more than counterbalance the natural Aformation pressure and/prevent flow from the Well.

It is, therefore, an importantobject -of this 4invention to provide a; novel apparatus for treating :a ,Well to festablishcommunication `between VVVthe annularspace exteriorly ,ofl arwell-flow con- Aductorabove a packer and the bore of the cono ductor'for admitting loading fluidsffrom such annular space to the-conductor and the` well for- 1 mation with which such conductor` communicates to kill the well.

It is also .-an object of the invention tov provide such an appaiatus-for/treating awell ywherein lthe establishing of communicationbetweenthe .annular space and the bore of the conductoris eiected withoutapplication of-extraneous pressure, without moving or rotating the conductor and without a flexibleline in the conductor Vat the time the communication is established.

A further object of the invention isV to provide an: improved apparatus for treatinga wel1, hav inga ow conductor therein witha packer for sealing off the 'annular space exteriorlyfofthe conductor, wherein aloading fluid is introduced into andL stored inthe. annular space abovexthe packer insufficient volume and oflsufficient consistency-to kill-'or preventffflow from thewelllwhen `2 suchloadingfluid isalso admitted tothe 4bore of the iiow conductor, the loading iiuidgbeing excluded from said flow conductor until it is ,de

`sired to kill the well, whereuponcommunication is established between the annular space andthe kbore of theconductor at a point above the packer by means utilizinguid pressure present inthe wellLandthe loadingviiuid is permitted Lto enter the` conductorto kill the well.

Another object of the invention-is to provide Va novel circulating device 'for a'well'ovw con- .flow conductor abovfefrthe` packer andthe bore of Vvide a circulating device, of the character `described, wherein theclosure means for the circulating ports is designed to withstand-substantially as `great a pressure'from-without the flow conductor as the ow conductoritself will stand, whereby the normaluse and the functioning of the owconductor isnotaffected or decreased' by the provisionA ofthe circulating device therein.

A further object of the invention is to provide a circulating vdevice ofthe character described having a plug for'closingfthe circulation port which is reinforced against displacement inwardly, and wherein the reinforcingr means isrremovvable to permit the closure plug to Vbe displaced from said circulation port.

A particularly important object vof the'invention is to providesin a circulating device, of the Vcharacter described, `a reinforcing sleeve forgprewell to, a. closure, memberadaptedlfbe lowered 3 or dropped into the well conductor and anchored in said sleeve, whereby the closure plug may be displaced from closing position by uid pressure to establish a path of communication between the exterior and interior of the flow conductor.

A still further object of the invention is to DIO- vide, in a well flow conductor having a packer connected therewith, a circulating device which may be opened by the applicationof the well uid pressure to a removable plug lowered or dropped into the well flow conductor and releasably connected to a removable reinforcing sleeve in the circulating device, whereby circulation may be established between the bore of the well ow conductor and the annular space above the packer without moving the well ow conductor.

Additional objects and advantages of the i11- vention will be readily apparent from a reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

Figure 1 is a schematic view of a well having loading fluid therein, and showing a packer and circulating device being installed in said well.

Figure 2 is a view similar to Figure l showing the packer in sealing position and the loading fluid stored in the annular space between the flow conductor and well casing above the packer,

Figure 3 is a view similar to Figure 1 showing the circulating device opened and the loading fluid admitted to the bore of the flow conductor to prevent ow from the well producing formation,

Figure 4 is a transverse vertical sectional view of a circulation device constructed in accordance with the invention, and showing the same connected in a well ow conductor,

Figure 5 is a view, similar to Figure l, showing the removable closure member releasably anchored in the reinforcing sleeve preparatory t opening the circulating device, and

VFigure 6 is a transverse vertical sectional view of the circulating device in opened position.

In the drawings, the numeral I0 designates an elongate tubular housing having an axial bore Il. External screw threads I2 are provided at each end of the housing, whereby it may be connected in a well now conductor or tubing string T by means of the usual couplings C. The housing is formed with an external annular ange I3, and one or more laterally extending or radial openings or ports I4 are formed centrallyof the ange. The outer portion of each port is enlarged in diameter, whereby an outwardly facing annular shoulder I is provided in the mid-portion of the port.

A closure member 0r plug I6, having an external annular flange I7 formed integral with its outer end, is positioned within the port to close the same. The flange I'I on the plug engages and is pressed tightly against the outwardly facing shoulder I5 in the port by means of a clamping bushing I8 which is screw-threaded into the enlarged portion of the bore of the port, so that the flange is clamped securely in place in the Dort between the shoulder I5 and the inner end 0f the bushing. The bore of the bushing is preferably slightly larger than theexternal diameter of the plug I6 and the reduced inner portion of the port I4.

The lower portion of the bore of the housing I0 is reduced in diameter,y whereby an upwardly facing seat I9 is formed in said bore at a point below the lateral ports I4, and a reinforcing sleeve 2B is slidably inserted into the upper portion of the bore of the housing and supported upon the seat. The bore 2I of the reinforcing sleeve is of substantially the same dimension as the reduced lower portion of the bore of the housing l0, whereby the flow of fluids through the housing is not restricted by the reinforcing sleeve.

One or more lateral recesses 22 are formed in the external surface of the reinforcing sleeve, being so positioned that they align With the lateral ports I4 in the housing. Each recess 22 is of a size corresponding to the size of the inner reduced portion of the port I4, and the inner end of the plug I6 projects into such recess when the sleeve is in place in the housing, as clearly shown in Figures 4 and 5. The recesses 22 extend only a short distance into the wall of the reinforcing sleeve, whereby the wall of the sleeve supports the plug against inward displacement from the port I4. The engagement yof the inner end of the plug with the recess 22 provides a frangible or shearable means releasably retaining the reinforcing sleeve in position in the housing.

Gbviously, since the flange Il is clamped Securely between the shoulder I5 and the bushing I8 and the inner end of the plug I6 is in engagement with the reinforcing sleeve 2t, any pressure uid acting upon the plug from exteriorly of the housing will only urge the plug more tightly against the reinforcing sleeve, and displacement of the plug inwardly of the port is thus positively prevented. However, if the reinforcing sleeve 20 is removed from within the bore of the housing, the application of a sufcient pressure difierential against the plug from exteriorly of the housing will force the plug inwardly of the port and will thus shear or break ofi' that part of the ange ii extending beyond the diameter of the reduced inner portion of the bore of the port and the plug will be displaced completely inwardly from the port to permit the now of fluids therethrough.

By varying the thickness of the iiange on the plug or the material from which the plug is made, or both, it will be seen that the pressure differential required to be exerted across the plug to displace the same may be controlled and predetermined. Therefore, the plug may be secured within the port so as to be displaceable at various predetermined iiuid pressure differentials after the reinforcing sleeve is removed.

In the majority of installations in which the circulating device is used, and in practicing the method herein set forth, the excess pressure will normally be from exterorly of the housing. It is preferable, therefore, that the plug be made of a relatively low shear strength material, such as lead or copper, since the reinforcing sleeve provide adequate support to prevent inward displacement of the plug from the port. Also, it is preferable that the plug be made of a relatively soft material in order that a iiuid tight seal may be obtained to close the port. The seal is secured by the compression of the ange of the plug between the bushing I8 and the outwardly facing seat I5 in the port, and a softer material such as copper or lead will adequately provide such a seal.

In normal use, the circulating device is connected in the well tubing string T by means of the couplings C, and is usually installed just above a well packer P which is adapted to ,seal between the conductor T and the well casing-S in the customary manner. It is customary to completely fill Vthe well borewith loading fluid when the-drilling operation-hasA been completed.` The well flow conductor'ortubing T is'I then loweredinto the-well' while the-loading fluid is still inthevbore` of the well, as shown in` Figure l, The packer is then 'set and the' loading vfluid in the tubing and in the -bore of the well-below the packer is then swabbed out in the customary manner. After the packer.' and tubing have been installed, thelcadi'ng uid, suchas water or mud, inthe annular space between-the well casing and the tubing: above the packer is stored or maintained therein for counterbalancingl the pressure of the fluids .from the well'producing formationacting upwardly against the` lower end of the packer. The column of loadingV fluid applies a pressure substantially equal to or in excess of the pressure of 'thelluidsfrom the producing formation; and thus reduces the effective upward force of the formation fluid pressure tendingY to unseal the packer. The plug I6, supported by the reinforcing .sleeve 20, prevents the loading fluid from entering the bore of the tubing through the port` I4, "since the seal created by the bushing clamping the llange l1 against the outwardly facing seatv i in the port prevents the loading fluid from passing lthrough the port. Of course, the loading fluid may be introduced into the annular space above the packer after the packer has been installed, if desired,

In practicing the methodv of this. invention however, the loading fluids'are preferably stored in the annular space between the wellv tubing and casing above the packer in sufficient quantity and of a suniciently heavy consistency to create a load pressure calculated or predetermined to be substantially adequate to completely kill or prevent flow Vof naturalwell fluids fromthe well producing formation if also vadmitted to the bore of the tubing communicating with the formation. These loading fluids are initially excluded from the tubing by the circulating device, but are present and in .constant readiness for admission to the tubing to .prevent flow of fluids from the formation and thereby kill the well. Therefore, it is only necessary to remove the reinforcing sleevey 20 upwardly o-ut of the housing, whereupon the pressure exerted upon the plugs i6 by the loading fluids exteriorly of the housing will force the plugs inwardly from the ports, and the loading fluids will be. admitted to the bore of the tubing to kill the' well. Since the quantity and weight of the loadinglluids create a load pressure considerably; in excess of the natural formation fluid pressure, there will always be a pressure differential acting upon the plugs of the circulating device tending to displace said plugs inwardly; and the strength of the flange on the plugs is sol predetermined that, when the reinforcing sleeve is removed, this differential will be adequate to fracture or shear thev flange yand displace 4the plugs. Thus, the pressures present in the well bore may be utilized to displace theplugs without the necessity of applying additional extraneous pressure at the well surface.

In order to remove the reinforcing'sleeve, the inner ends of the plugs I6 must be. severed or sheared, Vsince the engagement of the4 inner ends of the plugs in the recesses 22 of the reinforcing sleeve retain the reinforcing sleeve in position in the housing. Obviously, any desired. suitable means may be used for causing upward-movement of the reinforcing sleeve.- Hdwever, it is preferable thaty thesleeve-be-displaceable by means utilizing the iluidpressurepresentin the well. Therefore, thev reinforcing sleeve is illus-v trated as having an elongate internal annular locking vrecess 23 formedin the upper portion of to force the sleeve upwardly to shear or sever the inner end of the plugs. While other suitableforms of closure devices may be used, it ispref'erable that a device similar to that illustrated in the patent to Herbert C. Otis, No. 2,144,850, dated January 24, 1939, be used.

As clearly shown'in Figure 5, the retrievable closure device consists of an elongate carrier or mandrel 30- having a cylindrical neck 3l at its;

upper end extending upwardly from a flared or inclined shank 32, which later constitutes an expandingelement. The shank extends upwardly from a cylindrical head 33 from which a reduced stem 34 depends. The head is slightly smaller in` diameter than the bore of the reinforcing sleeve 20, so as to freely slidev thereinto.

A dog supporting collar 35 has a sliding Afit on the neck 3l and is provided with an undercut annular retrieving flange 36 at its upper end. A plurality of locking dogs 3l having elongate handles 38 are swingably and slidably. suspended from the lower end of the collar. A retaining collar 39 is mounted on the upper endof the neck 3l and limits upward movement of the collar 35 thereon. An annular stop flange 40 surrounds the base of the neck, and the handles of the locking dogs extend upwardly through slots in this flange. The flange is providedv with an annular downwardly facing inclined shoulder 4l which is adapted to engage an upwardly facing inclined annular seat 42 at the upper end of the bore of the reinforcing sleeve 20 to limit downward movement of the carrier or mandrel 30 within the sleeve.

The locking dogs have bosses 43 at their lower ends which are arranged to engage the downwardly facing annular shoulder 23a at the upper end of the locking recess 23 when said dogs are expanded by the flared shank 32 upon which they are slidable. When the dogs are at thev upper end` of the flared shank they are retracted and may enter and be withdrawn from the sleeve 2t, but when they are at the lower end of the shank they are expanded and will engage within the locking recess 23 to prevent displacement of the carrier upwardly out of the sleeve.

On the reduced'stem 34 a plurality of sealing cups 44 are mounted and held in spaced relationship by spacer rings 45. The cups are made of fabric impregnated with rubber, or other suitable composition, and are slightly smaller in diameter than the'bore of the sleeve 20, whereby they may readily enter the same. The well pressure fluid entering the bore of the sleeve expands the cups to sealing engagement with the wall of the bore of the sleeve; Two of thesealing cups are shown in position to seal off fluid pressures from below the device, while the upper sealing cup is turned upwardly and is adapted to seal off pressures from above.

A tubular valve cage 4B is screw-threaded onto the lower end of the stem 34 and confines the cups and spacer rings between its upper end and the lower end of the head 33. A ball valve 49 is resiliently held in seating relationship with the lower end of the stem 34 by a helical spring 5G '48. Openings 5|- permit-well fluid to flow into the bore of the cage to act against the ball valve.

Thus, with the surface iiow controls closed to prevent upward fluid ilow, the closure device P may be dropped or lowered into the well tubing until it is positioned in the reinforcing sleeve with the locking dogs 3l engaging in the recess 23. With the closure device in such position, flow of fluids upwardly through the sleeve is prevented and, when the surface flow controls are opened to permit fluid pressure above the closure device to escape, the full formation pressure is applied against the under side of the closure device to urge the same upwardly. Since the locking dogs are securely engaged against the shoulder 23a at the upper end of the recess 23 in the reinforcing sleeve, any upward force applied to the closure device will be transmitted to the reinforcing sleeve and such sleeve will be urged or forced upwardly by the well formation fluid pressure. As the plugs I6 are of a relatively low shear strength material, they will be sheared or severed when the well fluid pressure is applied with a sucient differential against the under side of the closure device P anchored in the reinforcing sleeve.

Once the reinforcing sleeve has been moved upwardly out of the housing, the loading fluid pressure from exteriorly of the housing will fracture or shear the flange Il on the plugs i6 to permit the plugs to be displaced from within the ports I4, whereupon the ports will be opened, as shown in Figure 6, and the loading fluids may flow through the ports into the bore of the well tubing. Since the loading fluids have been previously trapped or stored in the annular space exteriorly of the tubing with calculated or predetermined sufcient quantity and weight to be 'adequate to kill or prevent flow from the well when admitted to the formation from which flow is conducted through the tubing, it will readily be seen that the loading fluids will flow through the now opened ports to so kill or prevent further flow from the well (see Figure 3). Obviously, if necessary, additional quantities of loading fluids may be introduced into the annular space at the well surface without application of high pump pressure.

The closure device may be lowered into the well tubing by means of a suitable wire line lowering mechanism (not shown), the wire line mechanism being removed after the closure device is anchored in the sleeve and before the surface flow controls are opened. It is particularly desirable that the closure device also be capable of simply being dropped into the tubing, whereby it may be quickly inserted in place in the reinforcing sleeve in case of emergency. In either case, however, the closure device is installed in the reinforcing sleeve and the reinforcing sleeve is forced upwardly out of the housing by the pressure of the well fluid to permit the ports to be opened without movement of the tubing string or application of pressure from the surface.

Further, once the reinforcing sleeve has been removed, the plugs are readily shearable or severable to permit opening of the ports. Since the plugs are preferably formed of a relatively soft low shear strength material, such as lead, the flange Il may be sheared, severed or broken off upon the application of a relatively low fluid pressure differential, whereby opening of the ports is positively assured.

It will further be seen that the circulating device is initially closed, but may be readily opened to establish circulation between the bore of the tubing and theannular space exteriorly thereof without manipulation or movement of the tubing, and that such a circulating device is adapted to be installed in the tubing above a packer for establishing circulation between the annular space above the packer and the bore if the tubing.

It will particularly be seen that the circulating device is adapted to be opened by means utilizing the uid pressures present in the well, whereby manipulation of the tubing is eliminated and it is not necessary that any supplemental external operating force be employed to move the sleeve and displace the plugs to establish circulation through the circulating device.

Also, the reinforcing sleeve strengthens the plugs in the circulating device to such an extent that the device will withstand substantially as great a pressure from without the flow conductor as will the ilow conductor itself, whereby normal functioning of the flow conductor is not decreased by the installation of a circulating device. Further, the reinforcing means is releasably held in position and is movable from reinforcing position to permit the closure plugs to be displaced from the port in the circulating device.

It is also manifest that a novel method of treating a well having a flow conductor and a packer therein has been disclosed; wherein a column of loading fluid, in sumcient quantity and of sufficient weight to prevent flow of fluids from the well formation when admitted thereto, is stored in the annular space eXteriorly of the well flow conductor above the packer and initially excluded from admission into the flow conductor, a path of communication is then established between the annular space and the bore of the conductor and the loading iiuid is admitted through such path to the bore of the conductor for preventing uid flow from the well producing formation.

Obviously, the circulating device may be used in installations differing from the type already described, and for different purposes. Thus, it Imay be used for establishing circulation in either :direction through the ports, for circulating loading fluids out of the well, for unloading fluids from above a packer, and for like purposes. rIhe reinforcing sleeve may be removed from reinforcing position and the plug displaced from the port in the manner already described; ory it be so desired, the plug may be displaced outwardly of the port after the sleeve has been removed.

Once the plug has been displaced, the port is open to permit circulation of fluids therethrough between the bore of the tubing and the annular space exteriorly of the housing. The loading fluid in the annular space may then be circulated from the bore of the well in the usual manner, or additional loading fluid may be pumped into the annular space and now downwardly therein and through the ports I4 into the bore of the tubing, if desired.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A circulating device including, a tubular housing having a lateral circulation port formed therein and an internal stop shoulder below said 9 port, a plug fitting said'port initially closing'the same andhaving a shear tip on its inner end,

and a reinforcingsleeve slidable in the bore of formed therein establishing communication between the interior and exterior of said housing, a closure plug closing said port, a restraining member carried by the plug and secured in the portfor resisting displacement of the plug from the port, and a' reinforcing4 sleeve slidable in thehousing and supporting the inner end ofthe plug to prevent displacement of said Aplug inwardly from the port, said reinforcing sleeve having a recess in'its exterior surface receiving the inner end of the plug whereby the sleeve is restrained against movement from supporting position, said plug end being severable upon movement of the reinforcement sleeve upwardly away from supporting position, said sleeve thus being movable from supporting position to uncover the inner end of the plug and permit the plug to be displaced in from` the port, the restraining member being severable upon the application of a predetermined fluid pressure differential to the plug to permit the plug to be displaced from the port.

3. A circulating device including, a tubular housing adapted to be connected in a well flow conductor and having a lateral circulation port formed therein establishing communication between the exterior and interior of said housing, a plug closing said port, releasable means initially restraining said plug against displacement from the port, a reinforcing sleeve slidable in the housing and having a recess in its exterior surface for receiving the inner end of the plug to support the plug against displacement inwardly from the port and for restraining the sleeve against movement from supporting position, and upwardly closable fluid pressure actuated valve means removably positioned in the bore of the reinforcing sleeve for closing the bore of the sleeve whereby the fluid pressure in the well may be exerted against the valve means to move the sleeve upwardly away from supporting position and uncover the inner end of the plug, whereupon the plug may be displaced from the port upon application of a predetermined fluid pressure differential thereto to cause release of the releasable restraining means.

4. A circulating device adapted to be connected in a well flow conductor above a packer for establishing circulation between the interior and exterior of the flow conductor above the packer and including, a tubular housing having an axial bore and a lateral port establishing a flow passage between the bore and the exterior of said housing, a closure plug for said port having a shear member secured within the port to initially restrain the plug against displacement fromy the port, and a reinforcing sleeve slidable in the bore of the housing and having a recess in its exterior surface for receiving a portion of the inner end of the plug to support the plug -against upward displacement from the port and for restraining the sleeve against movement from supporting position, Isaid plug end portion being severable -upon upward-move- -Q ment of the sleeve awayjfrom supportingv position to uncover the innervend-of the plug and permit fluid pressure to be applied against the` plug to shear the shear member and displace the vplug from the port to establish communication between the bore-of the conductor andthe exterior thereof fabove the packer.

5. In -a-well flow conductor, acirculating device including, ahousing having a lateral circulation port formed therein, a closure plugclosingjsaid port and -having a reduced inner end portion, means on saidhousing engaging said plug initially restraining saidplug against dis-- placement outwardly from said port, aY reinforcing sleeve slidable in the housing and havinga recess in its exterior surface receivinga portion of the reduced inner end of the closure plug for restraining the sleeve against upward movement out of the housing and initially supporting the plug against displacement inwardly from the port, a-fluid pressure actuatable. closure member; -within the bore of the reinforcing sleeve, said reinforcing sleevehavingvalveseat means adapted to receive said closure member whereby the bore of the sleeve is closed against upward uid iiow and the fluid pressure in the well may be utilized to sever the plug end portion and move the sleeve upwardly away from supporting position to uncover the inner end of the plug and permit the plug to be displaced from the port in the housing, whereby communication may be established between the interior and exterior of the flow conductor at the circulating device.

6. A circulating device including, a tubular walled body member having a passageway extending from the interior to the exterior of said body member wall and forming a. flow port therein, a closure plug closing the port and having a reduced inner end portion, means on the body member engaging said plug whereby said plug is releasably secured against outward displacement from said port, a tubular reinforcing member movably carried by the body member in slidable engagement with the inner surface of the tubular walls of said body member, said reinforcing member having a recess in its exterior surface for receiving a portion of the reduced inner end of said plug and supporting the plug against displacement from the port in an inward direction, said plug end portion restraining the reinforcing member against longitudinal movement in the walled body member from supporting position, Isaid reduced plug end portion being severable to permit the reinforcing member to move from supporting position to uncover the inner end of the plug to permit displacement of the plug from the port, and upwardly closable fluid pressure actuated valve means removably positioned within the bore of the tubular reinforcing member closable by fluid pressure from below for moving the reinforcing member from plug supporting position to uncover the inner end of the plug.

7. A circulating device including, a tubular housing adapted to be connected in a well flow conductor and having a lateral passageway formed therein establishing communication between the exterior and the interior of said housing and providing a circulation port, the outer portion of said port being enlarged to Il provide an outwardly facing shoulder in the port, a closure plug for said port having an annular shear ange fitting in the port with the ange in engagement Vwith the shoulder, a bushing releasably secured in the outer portion of the port securely clamping the shear ange against the shoulder in said port to restrain displacement of the plug from the port and to prevent fluid leakage therethrough, a reinforcing sleeve slidable in the bore of the housing and provided with a recess in its exterior surface adapted to receive a portion of the inner end of the closure plug whereby the sleeve initially supports the plug against displacement inwardly from the port and the end portion restrains the sleeve against displacement from supporting position, said reinforcing sleeve bore having valve seating means, a uid pressure actuated closure member in said sleeve bore engageable with said valve seating means for closing the bore of the sleeve against upward low whereby the uid pressure in the well may be utilized to move the sleeve upwardly away from supporting position, said closure plug end portion being severable to permit the sleeve to be moved from such supporting position and to uncover the inner end of the plug, whereupon the shear ange on t-he 12 plug may be sheared upon the application of a predetermined fluid pressure differential to the plug end to permit the plug tov be displaced from the port.

8. A circulating device of the character set forth in claim 7, wherein the housing is provided with a plurality of radially spaced lateral circulation ports and plugs and the reinforcing sleeve is provided with a recess in its exterior surface for receiving the inner end portion of each of said plugs.

IRA A. MILLER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name v Date 1,579,141 Pierce Mar. 30, 1926 1,912,578 Halliburton June 6, 1933 2,058,825 Rallet et al. Oct. 27, 1936 2,144,850 Otis Jan. 24, 1939 2,185,522 Rollins Jan. 2, 1940 2,307,662 Baylor Jan. 5, 1943 2,343,076 Otis et al Feb. 29, 1944 2,393,404 Otis Jan. 22, 1946 2,397,473 Crowell Apr. 2, 1946

Images