US2295822A

US2295822A - Apparatus for cementing objects in well bores

Info

Publication number: US2295822A
Application number: US356767A
Authority: US
Inventors: Arthur L Armentrout
Original assignee: ELWIN B HALL; VIRGIL P BAKER
Current assignee: ELWIN B HALL; VIRGIL P BAKER
Priority date: 1940-09-14
Filing date: 1940-09-14
Publication date: 1942-09-15
Anticipated expiration: 1959-09-15

Description

. .7 L? v@ .5 Z5 W 2 Sheets-Sheet 1 A. L. ARMENTROUT Filed Sept. 14, 1940 Ill.. 1

APPARATUS FOR CEMENTING OBJECTS IN WELL BORES sept. 15,1942.

Sept 15, 1942-' A. L. ARMENTRouT 2,295,822

APPARATUS FOR CEMENTING OBJECTS IN WELL BORES Filed Sept. 14, 1940 2 Sheets-Sheet 2 ggf@ @UW/f/ APatented 15, 1942 "UNITED STATES wrrENT- 'or-FICE l, azssszz v APPARATUS FOB CEMNTING OBJECTS IN or of one-third to Elwin B. Bail and one-third to Virgil P. Baker Application September 14, 1940, Serial No. 356,767

14 Claims.

This invention relates to the art of cementing wells and has particular reference to a method and apparatus for cementing casings, liners, and like objects in well bores. A general object of the invention is to provide a rapid, efficient method and a simple, practical apparatus for cementing objects in wells.

Another object of this invention is to provide a practical method for performing multiple'stage cementing operations for the purpose of cementing water strings or casings and for cementing casings and liners at spaced levels to isolate spaced productive zones and to prevent the migration of water and other unwanted fluids to such zones. 4

Another object of this invention is to provide a multiple stage cementing method of the character referred to whereinv each stage or charge of cementslurry is separately and individually delivered to the well and individually placed in the selected portions ofthe annular space be- -tween the wall of the well bore and the lining of a single tubular string which serves to conduct the charges o! cement slurry to their respective places in the well, to carry the circulation iiuid or nushing fluid, to carry the bridgins plugs and packer and to control and support the control means and protective means for the bridging plugs.

' Another object of this inventionis to provide apparatus for carrying on multiple stage cementing operations that is safe and dependable and that is easily controlled. l

Another object of the invention is to provide multiple stage cementing apparatus that-does not require the installation of complicated valves, or the like, on the casing, liner, or other obiect installed in the well.

or well casing. In the method of the present invention the charges or bodies of cement slurry are individually passed down the weil one at a time for separate delivery to their respective places and there is no danger of such charges becoming stalled or blocked in the well. Another object of the invention is to provide a cementing method of the character referred to in which the cement slurry is effectively prevented from passing down in the casing or liner beyond the correct or intended point or points of discharge.

Another object of this invention is to provide a method of the character referred to in which the individual bodies or charges of cement slurry may be as small or as large asbelieved necessary and may be individually increased, as yfound necessary,

Another object-of this invention is to provide a cementing method of the character referred'to in hich the interior of the -well casing or liner an the cementing tool may be flushed free of excessive cement slurry following each stage cementing oper-ation.

Another object of this invention is to provide a cementing method of they character referred to that is particularly adapted to spot" or place bodies of cement slurry around a well liner at spaced levels or depths to isolate spaced productive zones of the well.

Another object of theinvention is to provide a well cementing method of the character re- Another object of this invention is to provide a multiple stage cementing apparatus embodying novel and effective means for "successively latching or locking the bridging plugs at their respective stations in the casing or liner.

Another object of the invention is to providet multiple stage cementing apparatus in which the bridging Plugs and their latches are fully housed and protected by novel means on the cementing string so that they are not worn or fouled when the apparatus is lowered into the well and are controlled so that they are freed for engagement in the casing or liner only upon reaching their respective stations.

Another object of the invention is to provide a cementing apparatus of the character referred n to that is operable-to accurately spot'or` locate one or more bodies of cement slurry at selected or pre-determined points in the well.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred manner of carrying out the method and a, typical form of apparatus of the invention, throughout which dcription reference is made to the accompnyins drawings, in which:

Fig. 1 is a vertical sectional view of a portion of a well boreswith a` liner arranged therein preparatory to the cementing operation, the liner and other parts being diagrammaticaily shown. Fig. 2 is a viewsimilar to F18. 1 with the cementing apparatus in position in'the liner. Fig. 3 is a view similar to Fig.'2 showing one of the bridging plugs engaged or latched inthe liner and illustrating the packer set so that cement slurry may be discharged under pressure above the set plug for discharge into the well. Fig. 4 is an enlarged fragmentary vertical detailed sectional ferred to that is characterized bythe employment view of the cementing apparatus showing the L joined by threaded couplings I2.

of the bridging plugs in the carrier. Fig.'5i is an enlarged fragmentary vertical detailed sectional view of a portion of the liner showing one of the shoulderedv ported parts and Fig. 6 lis a transverse detailed sectional view taken as indicated by line 6-6 on Fig. 4.

The method and have a wide range of application, being usefu1 in carrying on various well cementing operations. For example, the invention may be employed in the multiple stage cementing of a casing for any required distance, may be employed in the spotting of cement for any purpose, for the repair of leaks in a well casing, for the cementing of a liner, etc. In the following detailed disclosure I will describe the invention employed as illustrated The portion of the well bore illustrated pene-- trates three spaced productive zones A, B and C,

separated by non-productive strata D and E, which may or may not be water bearing. The lower portion of the water string or well casing i@ is cemented in the well at or above the upper end of the productive zone C. The liner L for the open productive portion of the well is a long tubular member or assembly received in the productive part of the well with some clearance to provide or leave an annular space. Theliner L may rest on the bottom of the well bore and the liner may be proportioned to have its upper part protrude into the well casing I0. It is to be understood that the liner L may be'suspended or supported inthe well in any of the well known manners and if desired may be sealed'cr packed off in the casing I0.

The present invention is not primarily concerned with the material or structure of the liner L. However, it will be assumed that the liner L is formed of a readily drillable material such as aluminum, an aluminum alloy or the like, and is made up of several tubular lengths or sections I I The liner L is provided with spaced perforated portions A', B' and C at the productive zones A, B and C respectively, to admit the well uid. A iioat shoe I3 is provided on the lower end of the liner L and has a valve I4 serving to prevent the entrance of duid to the interior of the liner and adapted to permit the outow of uid. The liner L is equipped with other elements which are employed in the cementing operations as will be later described.

The cementing apparatus of the invention may be said to comprise, generally, shouldered and ported parts X and Y on the liner L at or opposite the non-productive zones D and E, a iluid conducting operating string S, an expansible and contractible packer I5carried by the string S to seal with the interior 0f the liner L, a plurality of bridgingplugs X' and Y for latching or locking with the shouldered parts X and Y, respectively, and means I6 on the string S carrying the plugs X and Y to successively enga-ge with the parts X and Y.

'I'he shouldered and pass through what I will term non-productive zones D and E, being connectedor assembled in the liner L to occupy lsuch positions when the liner is naly set or hung in the well. The inapparatus of the inventionl of the parts X and Y in any preferred inanner. In the particular case illustrated each part X and Y isan integral nipple or coupling-like element interposed between and connecting adjacent sections Ii oi the liner L. 'I'he partsX and Y may be screw-threaded with the adjacent sections II of the liner L and may be formed of readily drillable material, for example, they may be formed of the same material as the liner sections. Each part X and Y has a pair of vertically spaced opposing internal shoulders I'I and I8. In practice I prefer to form a groove in the internal surface of each partX and Y and to shape the grooves so that their end walls constitute the shoulders I 'I and I8. Thus the part X is provided lwith an internal groove I9 and the part' Y hasa similar internal groove 20. The grooves the shouldered parts X and Y. Thereis prefer- I9 'and 20 are annular so that the shoulders lland I 8 are continuous. In accordance with the invention the grooves i9 and 2u are graduated in width to be selectively engaged by lock means on the plugs X and Y. In the construction illustrated the groove 20 in the upper part Y is considerably wider than the groove I 9 in the part X.

One or more ports 2l are provided in each of ably a plurality of circumierentially spaced ports 2i provided in each part X and Y. The ports 2l are spaced some distance above the grooves I9 and 20 and are provided to discharge the cement slurry into the annular space between the wall of the well and the liner L. Each .port 2I is equipped with a suitable inwardly seating check valve 9 to prevent the return of the delivered or discharged cement slurry. It may be desirable or necessary to provide a cement retainer or basket 22 on or adjacent each part X and Y below ,the ports 2i to` limit the downward flow of the cement slurry discharged from the ports. In the drawings I have shown baskets 22 of conventional form secured to the parts X and Y below the ports 2| and designed to seal withthe Wall -of the Well. It is to be understood that where the liner L is drillable all of theelements asf sociated with the liner may be formed of readily drillable material. v

'I'he string S serves as an operating string for the packer I5, the plugs X and Y' and the means I6, and operates as a conduit for delivering the cement slurry and flushing iiuid to the liner L. The string S may be made up of suitable Well pi'pe or tubing connected in the usual way by threaded couplings. The string S is proportioned to be received in the casing I0 and liner L with substantial clearance. It is to beV understood that the string S is tubular and continuous and -that pumps or other means are provided at the upper end `of the well for supplyin fluid under pressure to the string S.

The packer, I5 is operable to seal with the interior of the liner L and is arranged to be manipv ulated and controlled by the -string S. The

`packer I5 as shown in Fig. 4` includes an abut-vA ment or collar 23 xed to the string S, a sleeve 24 shiftable with respect to the string and a body of packing 25 between the collar 23 and the sleeve 24. The collar 23 may be threaded to the lower end of the string S and a mandrel 26 may be threaded in the lower end of the collar 23 to extend downwardly through the packer I5. The mandrel 26 constitutes a downwardly extending continuation of the string S and is tubular to conduct fluid. The lower end of the collar 23 is vention contemplates the v4forming and mounting 75 tapered or sloped upwardly and outwardly. The

shiftable abutment or sleeve 24 is arranged on the mandrel 23 at a point below the collar 23.

The upper end of the sleeve 24 slopes downwardly and outwardly. The packing r25 is arranged on the mandrel 23 between the collar 23 and the sleeve 24 and is an annular or tubular body of resilient compressible material. The upper and lower ends of the packing 25 are concave cups 33 at the upper ends of the plug bodies 35` to receive or cooperate with the tapered ends of the collar 23 and sleeve 24. The tapered When the packing 25 is compressed its periphery is brought into sealing contact with the interior of the liner L.

The packer I further includes a gripping means or slip means for holding the sleeve 24 against downward movement whereby the string' S may be lowered to. actuate or compress the packing 25. The lower portion of the sleege 24 is shaped to constitute a cone 21 and asset of slips 23 is arranged on the cone. Reins 23 depend from theslips 23 and are secured to a ring 33 which freely surrounds the mandrel 23. A second ring'3l is arranged around the mandrel 23 below the ring 33. A series of leaf springs 32 extends between and connects the rings 33 and 3|. The springs 32 are bowed outwardlyto frictionally engage the interior of the lining L and this engagement resists movement of the rings and the slips 23. Latch means is provided to control the slips 23. A hook-like latch 33 is secured to the ring 33 and is engageable with a pin 34 on the mandrel 23. When the latch 33 is in bodies u by pistes u. v 'rne rims or warns. or the cups 33 are ilared to effectively seal with the sur-V rounding internal surface ofthe liner L. The

face upwardly to be actuated or expanded by downwardly directed iluid pressure while the cups 33 at the lower ends of the plug bodies/face downwardly to be expanded by upwardly directed fluid pressure.

Valves 33 control the upper and lower ends of .the openings 31 in the plugs. The valves 33 may be ilapper type valves pivotally supported on the Vplates 33 at 43 to seal against the plates 33 or the ends of the plug bodies 35. Springs 4I are associated with the pivotal ,mountings 40 to urge the valves 33 to their closed positions. The bridging plugs X' and Y and the parts associated therewith are formed of readily drillable material to be drilled up by conventional well drilling tools. It is to-be understood 'that there is a l plug provided to engage in each shouldered part of the liner L and that the apparatus may embody any required number of bridging plugs of the character just described.

4Each bridging plug X and Y' is equipped with a latch means or lock means for cooperating with its respective shouldered part of the liner L. A i

plurality of spring latching or locking elements 42 is provided on the plug X to engage in the groove I3 of the shouldered part X. The locking elements 42 are spacedl around the plug body 35 and have their lower ends suitably secured to the lower part of the plug body. The spring elements 42V extend upwardly and outwardly and then straight up, each having a substantially straightvertical part 43. The parts 43 form shoes that are adapted to rideon` the internal v surfaces of the casing V I0 and the hner L when cooperation with the pin 34 the slips 23 are ren compression of the packing 25 so that it seals with the interior of the liner L. The packer I5 is such that the packing 25 returns to its initial size when relieved of the compression forces by upward movement of the string S'. Following such retraction of the packing 25 the string S` may be manipulated to release the slips 23 and re-engage the pin 34 with the sleeve 33 to again hold the slips intheir released positions.

The bridging plugs X' and Y' are adapted to form barriers or partitions across the interior of the liner L below the discharge ports 2l so that cement slurry or other fluid under pressure dellvered to the interior of the liner above the plugs is obliged to discharge laterally through the ports. The plugs X' and Y' may be alike in construction.

Each plug X' and Y' comprises an elongate central core or body 35 and sealing cups 33 on the opposite ends of the body, see/Fig. 4. The plug bodies 35 are smaller in diameter than the liner L and have central longitudinal openings 31. The sealing cups 33 of the plugs X' and Y' are arranged on the bodies 35 to seal with the interior of the liner L for the purpose of preventing fluid under pressure from passing the plugs in either direction. The cups 33 have flat central the apparatus is moved through the well. In accordance with the invention the parts 43 are proportioned to enter the groove I9 in the liner part X and the groove 20 or any other like grooves above the part X. The lock elements 42 are shaped to ride downwardly past the grooves I9 and 20 and any other similar grooves and operate to selectively enter their respective groove I9 upon subsequent upward movement. The springlocking elements 42 are shaped to latch or lock in the groove I9 when the shoe parts 43 enter the groove. Each lock element 42 has a downwardly and inwardly turned nose 44 at the upper end of Vits shoe part 43. The walls or shoulders Ilnand I3 of the groove I9 are preferably undercut and the noses 44 are sloped or shaped to lock under the shoulder I1. The engagement of the noses 44 with the shoulder I1 dependably locks the plug X' against upward movement in the liner L.

The bridging plug Y' is provided with a plurality of spring locking elements 45 similar to the above described elements 42. The locking elements 45 are spaced about the body 35 of the plug Y and have their lower ends secured to the lower part of the plug body. The elements 45' slope upwardly and outwardly and have substantially vertical shoes 43 adapted to ride on the internal surface of the casing I0 and the liner L. The shoes 46 are proportioned to readily enter;

the groove 23m the shouldered part Y but their length is such that they cannot enter the groove I 9 or other similar grooves that may be provided in the liner below the groove 20. Downwardly and inwardly directed noses 41 are provided on the upper ends of the shoes 43 to cooperate with the shoulder I1 of the groove 23. The walls or shoulders l1 and I3 of the groove 20 are un- -houses the bridging plugs X and Y'.

dercut and the noses 41 are adapted to engage the undercut shoulder I1 to dependably lock the` plug Y against upward movement in the liner.

'I'he plugs X and Y' are further provided with x means ycooperable with the shouldered parts -X and Y, respectively.- to latch or hold the plugs against downward movement. Each plug X and Y Y' has av number of downwardly and outwardly sloping latch fingers or lock ilngers 48 for cooperating with the shoulders I8. The ngers 48 are spaced between the

lock elements

42 and 45 and are suitably attached to the upper portions of the plug bodies 35. The outer or lower parts of the fingers may be straight or:` substantially ,vertical to better lock with the shoulders I8. The -fingers 48 are adapted to engage with the shoulders I8 of the related parts X and Y to dependably support or hold the plugs X' and Y against' downward movement.

The means I6 serves to support the plugs X and Y' and to house and protect the plugs when the tool or equipment is manipulated in the well. The means I is such that the plugs X' and Y' may be individually released when engaged in their respective shouldered parts X and Y as the stage cementing operations progress. In the' preferred form of the invention the means I5 includes a stem or tube 49 connected with the lower end of the mandrel25 and extending downwardly therefrom. A head or collar member 5I)a may sei-ve` to connect the tube 49with the mandrel 26.

their shouldered parts X and Y. Longitudinally extending slots 53 are provided in the cage 52 to freely receive or pass the outer portions of the

latch elements

42 and 45. 'I'he slots 58 extend tothe lower end of the cage 52 so that the l cage may be moved upwardly from the plugs X' The tube 49 is proportioned to be received in the openings 31 of theplug bodies 35. The plugs X and Y' are arranged on the Atube 49 from its lower end, therplug Y? being arranged above the plug X'. As illustrated in Figs. 2, 3 and 4 of the drawings the tube 49 passing through the openings 31 holds the valves 39 in their open polsitions. The openings 31 shiftably or slidably receive the tube 49 so that the plugs may be successively disengaged from theV tube. The tube 49 serves as a iluid conductor constituting a continuation of the string S and being operable 'to discharge the ushing uid, cement slurry, etc. from the lower end of the tool.

Means are provided for releasably securing the plugs X' and Y' to the tube 49. Shear pins 50 are4 arranged through radial openings in the plug bodies 35 to engage in openings or sockets 5I in 'the wall ofthe tube 49, see Fig. 4. The pins 50 serve to retain the plugs X and Y' in their initial positions on the tube 49 until after the plugs A and Y' as the

lock elements

42 and 45 successively engage in the shouldered liner parts X and Y. The slots 53 expose the shoe parts of the

elements

42 and 45 for free engagement with the internal surface ofthe liner so that the lock elements may engage in the parts X and Y. It will be observed that the cage 52 iullyand eiectively houses the plugs rX and Y' to prevent wearingot the plugs and fouling of the plugs during movement of the apparatus in the well.

The operation of the apparatus and the method o f the invention, employed as illustrated in the drawings, may be said to comprise, generally, the setting or positioning of the'liner L in the well, lthe lowering of. the string S in the' well to bring the packer I5 to a position below the lowermost ports 2|, the actuation of the packer I5, the delivery of cement slurry under pressure through the string S to the lower portion of the liner L for discharge from the vshoe I3, the releasing of the packer I5 and the raising of the apparatus to bring the packer toa position above the part X and to cause the plug X' to latch in the part X, the actuation of the packer I5, the passage of cement slurry under pressure down through the string S for delivery to the ports 2| of the part X, the releasingand raisy ing of the packer I5, the repeating of the cementhave been latched .or locked in their respective `shouldered partsy X and Y of the hner L whereupon the pins may be broken to permit the withdrawal of the tube 49 from the plugs.

The means I8 further includes a housing or cage 52 for the series of plugs X' and Y'. cage 52 is a tubular element whose upper end is iixed to the collar member 50"as by welding. The

cage 52 surrounds thev tube 49 with substantial The clearance leaving a chamber or space which.

I the cups 35 and the latch fingers 48 of the plugs may bear outwardly against its internal surface.

The plus enclosing cage 52 is formed to perdown through the string S to discharge into the mit the engagement of the lock elements 45 with 75 ing operations at the part Y' and at the shouldered liner parts thereabove, followed by the withdrawal ofthestring S and the removal oi the bridging plugs X' and Y'. In addition to these general operations the liner L and the cementing equipment may be flushed or washed preparatory toand following each stage cementing operation.

` Assuming that the liner L is set or positioned in the well and that the liner and well are conditioned for the reception of the cement slurry, the string carrying the cementing equipment is run down in the well to a position such as illustrated in Fig. 2 of the drawings. The string S is lowered to-bringthe packer I5 below the part X and to bring the discharge end of the tube I9 adjacent theshoe I3. If desired or necessary, iiuid may be pumped down through the string S to discharge from the tube 49 to ilush the lower portion of the liner and to clean the cementing apparatus. The string S is turned a short distance and moveddownwardly to release the pin 34 from the latch 33 and subsequent downward movement of the string sets the slips 28 and compresses the packing 25. With the packer I5 set or actuated to seal with the interior oi? the liner L a suitable distance above the shoe I3 a quantity of cement slurry under pressure is pumped liner at or above the. shoe I3. This cement slurry passes through the valve I4 into the well and iiows up around the lower portion of the liner. This body of cement slurry serves to seal o the wellbelow'the'lower productive ,zone A.

Following the delivery of the iirst body of cement slurry, the string S is manipulated to release the packer I5 an'dto re-engage the pin 34 with the latch 93, whereupon water or flushing uid may be pumped down through the string S to remove excessive cement from the lower part of the liner and to iiush the cementing tool. "The ilushing iluid is free to pass upwardly in the liner around listened plus Y'. The string s is moved ur.

the cage l2 and around the retracted packer ii. v

With the nrst cementing operation completed A`the string S is raised to move the cementing tool the plug X' in the part X and of course resists upward movement of the string'S. This sudden resistance to upward movement of the string S informs the operator that the plug X' has latched in the part X. An upward pull of increased intensity is then placed on the string S to insure the breaking of the shear pin lll so that the continued upward movement of the string S withdraws the tube 40 and the cage 52 from the plug X'. 'I'his frees the latch ngers Il of the plug X' and the fingers engage in the groove I! to prevent downward movement of the plug X' in the liner. The sealing cups 36 of the plug X' are automatically conditioned to seal with the interior of the liner L and the valves l! of the plug X' automatically close when the tube Il passes upwardly from the plug.

`Following the setting or latching ofthe bridging plug. X' the string S is again manipulated to actuate the packer Il so that the packer is made to seal with the interior of the liner L above the plug X'. A quantity of cement slurry under pressure is then passed down through the string S to discharge inthe liner L adjacent and aboveV the bridging plug X'. This cement slurry under pressure is free to discharge through the ports 2| of the part X to surround and seal about the liner in the unproductive zone D. It will be observed that the bridging plus X' and the packer I5 limit or prevent movement of the cement slurry up and down in the liner obliging the cement slurry under pressure to pass out through the ports 2| in the part X. Pressures that may develop in the liner L below, the part X cannot interfere with the cementing operation, the plug X' serv- ,ing to effectively hold back such pressures. If it is believed that additional cement slurry should be delivered to the well the operator may pump such additional cement slurry down through the string S to increase' the volume of cement discharged into the wellat the zone D. The basket 22 associated with the partX limits the down flow of the cement slurry and a body or column of cement slurry builds up around the liner in the stratum or zone D. Following the cementing operation in the zone D the string S is l manipulated to release the packer I5 and wash- `4iiuggiiuid may be pumped down through the string sistance to .upward movement of the string S informing the operator of the engagement of the l plug Y' in the part Y. An increased upward pull is then put on the string S to break the shear wardly to completely free, the tube Il from the plug Y' and is then manipulated to actuate the packer Il.

The apparatus is then ready for the third cementing operation. A selected .quantity of cement slurry is pumped down through the stringrr S to discharge from the tube ll above the plus Y'. The cement slurry under pressure passes out throughthe ports 2| inthepartYtosealoff around the liner in the stratum of none E. Pollowing the cementing operation at the sone E the string S is manipulated to release thepacker Ii and washing i'luid may be pumped down through' the string Sp to wash away excessive cement slurry from the liner and the tool. The string ,S may then be withdrawn from the well. To

condition the liner L for production the frangible 0 or drillable plugs X' .and Y' are removed. The plug X' and Y' may be removed by drilling them out with a suitable drilling tool or by breaking them out. This conditions the well for production Vor for the installation of additional equipment.

When the method and apparatus of the invention are employed to close or repair a leak in a previously set well casing, or the like, the location of the leak is ilrst ascertained. The apparatus of theI invention is assembled to embody a single plug, say the plug X', the plug being proportioned to seal or close the casing. The string S carrying the apparatus is then lowered through the casing to bring the sleeve I2 below the coupling in the casing below and closest to the leak. As well known to tho skilled in the art the couplings of well casings form or have 2 0, above described. When the string S 'been lowered to the position above mentio it is raised until the lock parts Il of the plug X' engage inthe casing coupling below the leak.

r w. lli and the string is moved upwardly to withdraw` the tube 4I and the cage 52 from the An up-pull is then put on. the string S to break the shear pin 50 and the string S is moved upwardly to draw the sleeve 52 upwardly from the plug X'. This allows the spring ngers ll to engage in the casing coupling. The packer II is then set or actuated at a point above the leak in the well casing and cement slurry under pressure is pumped down the string. The plug X' set in the casing below the leak prevents the cement slurry from flowing down the casing and the plug X' and the packer I5 closing oif the casing below and above the leak oblige the cement slurry under pressure to pass out through the leak. The cement slurry thus discharged intothe well at the leak closes or seals the leak. Following .the delivery of the cement slurry the packer i5 is released and the string S is withdrawn from the well. The plug X' is. then ref moved from the well, for example, it may be drilled up by a well drilling tool.' From the above it'will be apparent that the method and appaf those skilled in the art or fall within the scopeA of the following claims:

Having described my invention,-I claim: LYApparatus of the character described comprising an elongate album object te Ime installed in a well and having a plurality of longitudinally spaced ported parts, a bridging plug for each ot lsaid parts having means for locking in the same,

a tubular' well string for conducting iluid into the well and ladapted to be entered into said object and means on the string for simultaneously carrying the several bridging plugs to be successively locked in their respective` ported parts as the string isrnoved in the well.

2; Apparatus of the character described comprising' an elongate tubular object to be installed ,in a well and having a plurality of longitudinally spaced ported parts, a bridging plug foi` each of said parts having means forl locking in the same, -a tubular Well string for conducting iluid into the well, means for detachably securing the plugs to the string to be run into the well thereon and to be successively locked in Atheir respective ported parts as the string is moved upwardly in` ing the plugs on the string for detachment therefrom when the locking means are made operative 2,295,822. 6. In apparatus ofthe character described, a`

tubular object to be installed in a well. said object having a series of longitudinally spaced internal grooves, said grooves being graduated in width from oneend of the series to the other, a tubular well string adapted yto conduct uid into the well, a plurality of plugs for installation in said object, there being a plug for installation in the object at each groove, a lock means on each plug engaging in its respective groove to secure the plug in the object, sealing parts on the plugs for sealing with the interior of the object, means for securing the plugs to .the string releasable by manipulation of the string when the plugs are locked at their respective grooves, and a cage on the string for housing the plugs to protect their sealing parts, the lock means of the plugs being graduated in size and the plugs beingl arranged in order on the string so that the plugs may be successively locked at their respective grooves by longitudinal movement of the string in the object.

'7. In apparatus of the character described, a tubular object to be installed in a Well, said object having a series of longitudinally spaced internal grooves, said grooves being graduated in width from one end of the series to the other, a tubular well string adapted to conduct fluid into the well, a plurality of plugs for installation in said object, there beingva plug for installation in the object at each groove, a lock means on each plug engaging in its respective groove to and supporting the plugs in the order to be l successively locked in their respective parts when the string is moved upwardly in said object, and a releasable packer on the string above the last named means operable by manipulation of the stringto seal with the interior of said object internal grooves, said grooves being graduated in width from one end of the series to the other, a plurality ofplugs ,for installation in said object, there being a plug for installation in the object at each groove, a tubular well string for simultaneously moving the plugs in the object and adapted to conduct iiuid into the well, and a lock means on each plug for engaging with its respective groove, the lock means of the plurality of plugs being graduated in size so that the plugs are successively locked at their respective grooves upon movement of the string in one direction in the object.

5. In apparatus of the character described, a tubular object to be installed in a well, said secure the plug in the object, sealing parts on the plugs for sealing with the interior of the object, means for securing the plugs tothe string releasable by manipulation of the string when the plugs are locked at their respective grooves, a cage on the string for housing the plugs to protect their sealing parts, thelock means of the plugs being graduated in size and the plugs being arranged in order on the string so that they plugs may be successively locked at their respective groovesrby longitudinal movement of object having a series of longitudinally spaced in the object, the lock means of the series of plugs being graduated in size and the plugs being arranged in order on the string so that the plugs maybe successively locked at their respective grooves by longitudinalmovement of the string in one direction.

the string in the object, and means on the string above the cage for sealing with the interior of the object.

8. Apparatus oi the character described for l use in a tubular object in a well having spaced shoulders and a port, the apparatus comprising a tubular well string for conducting fluid into the well, a plug for the object, lock means on the plug for cooperating with the shoulders to lock the plug in the object, means attaching the plug to the string at a point above the lower end of the string, so that the plug may be run into the object on the string and uid may be passed down the string to discharge into the well below the plug and so that the plug -may there after be raised by the string to have its lock means cooperate with the shoulders, the last named means being releasable by manipulation of the string following such locking so that the string may be raised through the locked plug to bring the lower end of the string to a point above the plug, and a packer on the string operable to seal with the interior of the object above the plug whereby fluid passed down the string to discharge therefrom above theplug to flow from l said port cannot ilow upwardly in said object.

9., Apparatus 4of the character described for use in a tubular object in a well having spaced shoulders and a port, the apparatus comprising a tubular well string for conducting uids into the well, a plug for the object, lock means on the plug for cooperating with the shoulders to lock the plug in the Yabject, the lock means including a resiliently mounted lock part for engaging one of said shoulders, means attaching the. plug to the string at a point above the lower end of the string, so that the plug may be run into the object on the string and fluid may be passedv down the string to discharge into the well below the plug and so that the plug may thereafter be raised by the string to have its lock means cooperate with the shoulders. the vlast named means being releasable by manipulation of the string following such locking so that the string may be raised through the locked plug to bring the lower end of the string to a point above the plug, and a packer on the string operable to seal with the interior of the object above the plug whereby fluid passed down the string to discharge therefrom adjacent the plug to flow frornsaid port cannot ow upwardly in said object.

10.' Apparatus of the character described for' use in a tubular object in a well having spaced shoulders and a port, the apparatus comprising v A a tubular well string, a plug for the object, lock means on the plug for cooperating with the shoulders vto lock the plug in the object, thelock means comprising a lock part on the plug for engaging upwardly against one shoulder and a lock part for engaging downwardly againstv the other shoulder, means attaching the plug to the string at a point above the lower end of the string, so that the 'plug may be run into the object on the string and uid may be passed down the string .to discharge into the well below the plug and so that the plug may thereafter be raised by the string to have its lock means cooperate with the shoulders,- the last named means being releasable by Lmanipulation of the Y string following such locking so that the string may be raised through the locked plug to bring the lower end of the string to a point above the downwardly engaging part retracted and releasable from the same upon disengagementof the st ring from the plug. A

12. Apparatus of the character described for use in a tubular object in a well having spaced shoulders and a port,A the apparatus comprising a tubular well string for conducting fluid into the well, a plug for the object, loci; means on the plug for cooperating with the shoulders to lock the plug in the prising parts engaging upwardly and downwardly against said shoulders, sealing means on the plug for sealing-with the interior of the object, means for securing the plug to the string and designed t release under an upward strain when said upwardly engaging4 part is in cooperation with its shoulder, and means for holding the downwardly engaging part retracted Vand releasable from the same upon disengagement of the string for conducting fluid into the well, a bridging plug for closing said object, means on the plug for locking with said shouldered part to lock the plug in the object, and releasable means 4attaching the plug to the string at a point above the lower end of the string so that the string may be employed to lower the plug through the object to a point below said part and then used to conduct fluid downwardly for discharge into the object below the plug, and so that the string may thereafter be raised to cause the mst named meansto lock the plug in said shouldered part and release the releasable means whereby `this 4 string may be withdrawn upwardly through the plug, and a packer on'the string operable to seal with the interior of the object above the plug whereby fluid passed down the string to discharge therefrom above the plug to flow from said port cannot ilow upwardly in said object.

l1. Apparatus of the character described for use in a tubular object in a wellhaving spaced shoulders and a port, the apparatus comprising a tubular well string for conducting fluid into the well, a plug for the object, lock means on .end of the string the plug for cooperating with the shoulders to lock the plug in the object. the lock means comprising parts engaging upwardly and downwardly against said shoulders, sealing means on the plugfor sealing with the interior of the object. means for securing the plug to the string and designed to release under an upward strain when said Aupwardlyengaging part is in cooperation with its shoulder,

-parh the last plug to-discharge nuid above the plug.

14. In apparatus vof the character described, a tubular object adapted for installation in a well. a shouldered and ported part on the object. a bridging plug -for closing said object, means on the plug for locking with the shouldered part, a tubular well string adapted t be lowered into said object, releasable means for securing the plug to the string employed to run the have its lock means lock with the shouldered named means being releasable following said locking so that the string may be withdrawnupwardly through the P1118. and .a

packer on thev string for sealing'with the in.-

and means for holding the iii)v terior of said obiect above said part whereby fluid maybe passed down the stringtodischarge from the string above the plug and passentVV through the portof said part.

llamar..

object, the lock means com-A ata.pointabovethelowerv sothat thestringmaybe plus. into said object to