US3064734A - Bridge plug - Google Patents

Description

Nov. 20, 1962 L. w. roELKE 3,054,734

BRIDGE PLUG Filed oct. 1s, 195s 5 sheets-sheet s Il 'will' NOV. 20, 1962 L. w. TOELKE 3,064,734

BRIDGE PLUG Filed Oct. 15, 1958 5 Sheets-Sheet 4 INVENTOR. @.Jzefd VV. 7'0 e//fe BY Kama/I Nov. v20, 1962 L. W. TOELKE BRIDGE PLUG Filed Oct. 13. 1958 5 Sheets-Sheet 5 eJef l/V. Toe//ce INVENTOR.

60m. duk BY miie-J A fr0/QMS Ks United States Patent O M 3,064,734 BRIDGE PLUG Lester W. Toelke, Houston, Tex., assigner to Great Lakes Carbon Corporation, New York, NX., a corporation of Delaware Filed Oct. 13, 195%, Ser. No. 766,971 9 Claims. (Cl. 16d-63) The present invention relates to bridge plugs.

Bridge plugs are set in eil, gas and like wells for many reasons. For example, bridge plugs are used for remedial plug back work, as a temporary or permanent bridge for abandonment, cementing, squeezing, acidizing, protecting producing zones, plugging oif zones to produce from other zones, protecting well equipment and for use with testing tools and the like as Well as other uses. Heretofore in setting bridge plugs and in methods of bridging wells or methods utilizing bridging plugs it has been necessary to remove the tubing, kill the well and run a plug of a size just slightly less than the bore in which it is to be set. These plugs are generally known as casing bridge plugs. In pulling the tubing of course, a rig is necessary as well as other work-over tools which is quite expensive and requires many man hours.

It would be highly advantageous to provide a method of bridging a well and a bridge plug therefor and methods utilizing bridging plugs in which it is unnecessary to pull the tubing from the well, kill the well and avoid the use of expensive rig equipment and man hours necessary for that purpose. The present invention is directed to such bridge plugs.

It is therefore an object of the present invention to provide a bridge plug for bridging wells and provide methods utilizing bridge plugs in which it is unnecessary to remove the tubing from the -Well bore or to kill the well with all Itheir inherent disadvantages and expense.

Still a further object of the present invention is the provision of an apparatus for bridging a well and a bridge plug therefor and a method utilizing a bridge plug in which the bridge plug is lowered downwardly in the tubing, set in the casing belov the tubing to providea bridge base for bridging the well and in which suitable bridging materials are placed on top the bridging plug through the tubing, for example, bridging aggregate and then a suitable sealing material such as cement, various plastics, chemical Sealers, resins and the like.

Still a further object of the present invention is the provision of an apparatus for bridging a well in which a bridging base is lowered downwardly through tubing in the well and set in the casing below the tubing and, subsequently, suitable bridging material is placed on top the lbridging base thereby satisfactorily bridging and sealing the well.

Still a further object of the present invention is the provision of a method of bridging a well and of providing a bridge plug for a well in which the bridging operation may be performed by means of an electric conductor cable or a wire line.

Still la further object of the presen-t invention is the provision of a bridging plug which is retractable to the extent that it may easily and readily be lowered by means of a wire line inside t'ne tubing and includes means by which it may be expanded into bridging engagement with the wall of the casing or well below the tubing, which wall is generally of a larger inside diameter than the tub- Yet a further object of the present invention is the provision yof such a bridging plug which carries bridging elements adapted to fall upon the bridging plug as it is being set.

Still a further object of the present invention is the provision of a bridging plug which may be used for a wide 3,054,734 Patented Nov. 20, 1962 ICC Variety of bridging uses, for example, one that may be lowered in the tubing and set in the ,tubing or lowered through the tubing and set in the casing or may be lowered in the casing and set in the casing or in the open hole for any and all of the usual bridging plug purposes.

Yet a further object of the present invention is the provision of a bridging plug of the charter mentioned which is completely drillable.

Still a further object of the present invention is the provision of a bridging tool which is positive and eicient in operation and economical to operate and set.

Still a further object of the present invention is the provision of a bridge plug assembly in which the bridge plug is made of drillable material but the other parts of the assembly, for example, the setting assembly, are made of a material, such as steel, so that they may be used again and again. v

A still further object of this invention is the provision of a complete bridging and sealing assembly in which a combination bridge plug, setting assembly and sealing assembly are run into the well at the same 'time and coact t0` bridge and seal the well in one trip.

Other and further objects, features and advantages will be apparent from the following description of presently preferred examples of the invention, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings, where like character references desig-v nate like parts throughout the several views, and where; FIGURE 1 is a diagrammatic view, in sectional eleva' tion, of a -bridging plug assembly according to the invenf tion and useful in the method of the invention showny lowered into position below tubing in a well bore for expanding into bridging engagement with the casing.

FIGURE 2 is a view similar to FIGURE 1 lillustrating the bridging plug expanded into bridging engagement with the casing including bridging elements disposed on the bridging plug,

FIGURE 3 is a view similar to that of FIGURES 1 and 2 illustrating dumping of bridging cement on top of the bridging plug and bridging elements,

FIGURE 4A is a sectional elevational view of the upper part of the setting assembly of the bridging plug illustrated in FIGURES l-3, inclusive,

FIGURE 4B is a continuation of FIGURE 4A illus-,- trating an upper intermediate portion of the setting assembly and bridging element assembly,

FIGURE 4C is a continuation of FIGURE 4B illustrating a lower intermediate portion of the setting assembly, bridging element assembly, and bridging plug,

FIGURE 4D is a continuation of FIGURE 4C illustrating the lower portion of the bridging plug,

FIGURE 5A illustrates the upper portion of the setting assembly when it has been actuated to expand the bridging plug into bridging engagement with the casing,

FIGURE 5B is a fragmentary, sectional elevational View illustrating the bridging plug in expanded position,

FIGURE 6 is a cross-sectional View taken along the line 6-6 of FIGURE 5B,

FIGURE 7 is a fragmentary elevation, partly in section illustrating a sealing assembly in combination with the bridge plug assembly,

FIGURE 8 is a View similar to FIGURE 7 illustrating dumping of the sealing material,

FIGURE 9 is a fragmentary elevational View, partly in section, illustrating a method of sealing a formation traversed by the well bore, and

FIGURE l0 is a view similar to FIGURE 9 illustrating the sealing material being washed out of the casing with the formation sealed off.

Referring now to the drawings, and particularly to FIGURES l, 2 and 3, the bridging plug assembly 10 is illustrated as being lowered on the wire line 12 through f. 3 the tubing 14 to be set in the casing 16 in order to seal olfy a depleted oil or gas zone 18 so that production may be obtained from the upper oil or gas zone 20. Ordinarily the packer 15 is provided to seal oil the space between. the tubing `14j and casing 16 although the packer ISn'iaybeV omitted',v if desired. l l

The, illustrations in FIGURES l-'3, inclusive, are of a typical and highly advantageous use of the present invention, however, as previously mentioned, the' bridging'plug may be used forY all`r bridging purposes.

Y Turning no`w to the details of structure of a presently preferred apparatus of the invention as disclosed in FlG- URES 4A-D', inclusive, the bridge plug assembly 10 includes a setting assembly A (FIGUREAA), a bridging element section o r assembly B` (FIGURE 4B), a bridging plug' C v (FIGURES 4CV and 4D) and .a centralizer D (FIGURE, 4D), As will be apparent later, the bridging element section B and centralizer section D may be omitted, however, these are highly advantageous in use.

Referring now to FIGURE 4A, a cable connection 22 is providedY atthe. upper portion of the bodyI 24 of setting assembly' A forr connecting the bridge.. plug asusemblyvl()` to the `wire" lineV` .112, vThe cable connection Y 22may be of anyupreferred type and is here shown as a threaded connection Vto. the upper part of the body V24: althoughit may be secured in other ways, An electric conductor 2,6,is disposedv in.y the. wireline 12, as usual,

which. electric; conductor 2 6V is connectedV to thel electric Contact, 2S-disposed i-nthefiririg chamber 30 in the upper endvof the body 24. TheV electric contact: 28. is, insulatedbymeanso thetubulan insulator 32 threaded onto' th electric contact 28 which isfhere inthe form of` a threaded memberfor ease` of assembly.

Disposed,withinthenring chamber 30 are, the electric r'ing'cap.. 34; and the propellant 36, the cap 34 being eleetr'ic'ally connected.' by theelectric conductors 3S and 40: tothe electricl contact 2.8 by means of the nuts 29 threadedto electric contact 2.78. and. to a threaded ex,- tensicni` of. wire line or cable connection 22 which serves Yas a ground thereby completing the circuit to the cap. 34, Thev purpose of the cap 34 and the propellant 36lis to provide the setting forcefor the setting assembly A. Any preferred eap or squib 34 and. propellant 36 may be 11Std.-

The; lower. par-tof the. body 24 has a reduced diameter portion or piston 441which slidablyextends into an intermediate body portion 4 6., of the setting assembly A, the lower end, 43 or the reduced diameter portion 44 and the inner end G of the intermediate body portion 46 form'ngan'expansion chamber 52 for a purposeY later described. l

A vsetting mandrel 54 is threadedly or otherwise secured to1 thelower end o fA the reduced diameter portion 44 of the body 2 4, which settiugmandrel 54 slidably extends through the intermediate body portion 46.

uDisposed in the body 24 is the duct 56 leading `from the tiring chamber Sil which communicates with the duct 58,Y disposed inV the upper portion of the mandrel 54 and they choke. screw 69, the duct 58 having thelaterally extending ductsA 62 so that expanding gases from the explosive propellant 36 flow through the duct 56, the chokescrew 60, the duct 5S and out the lateral ducts 62 andinto' the expansion chamber 52 for bearing against the shoulders 48 and Si) thereby moving the reduced diameter portion 44 of the body 24 in the intermediate body section 46 outwardly relative to one another.

The choke screw 60 effectively increases the gas velocity and reduces theA pressure build up rate to effectively provide a setting force for the setting section or assembly A. This'is not necessary, however, and the choke screw 60 mayV be omitted. By the use of the choke screw, however, it is unnecessary to use a slow burning powder although a slow burning powder may be used if desired. Thus, it will be understood that any suitable arrangement by which suiiicient setting force is provided may be used.

The intermediate body portion 46 of the setting assembly A terminates at its lower end in a threaded pin 64 which is threadedly connected inthe box e6 of what might be termed the bridging material or junk ring section B of the bridging plug assembly. This last-mentioned` section. includes an upper body portion 68 which serves as a hold down adjustment sleeve for the split junk rings b disposed about the bridging material mandrel 72 whichY is threadedly connected to the lower head member 7 4 of the setting mandrel 5d. The enlarged head' member 7:4 also serves to limit upward movement of the mandrel 54 relative to therouter' body sections of the tool by engaging the lower end 76 of the pin member 64; llf desired, the shock absorber 75 may be added at the upperV end Vof the headinember 74 or it may be omitted.

' As illustrated, a plurality ofv segmental junk rings 7i) are disposed along a substantial length of the bridging material mandrel 72 and a release spacer 78 having an enlarged internal diameteris. provided to` insure release ofY the bridging plug C upon setting ofthe tool as presently described. I-t is notedthat the hold down sleeve drarid the junk rings 7G have the intertting portions l80 and 82,

as does the spacer release element 78, to insure that, the,V

junk ring 74% and the spacer release element 73 are releasf ably secured together when lowering orY otherwise moving the bridge assemblyl in the. tubing or casing, asy may be thecase. k Y

Similarly, the upper bridge plug body section S4 is provided with the upwardly extending peripheral ring 3431 'whichinterts into the peripherally-recessed portion 820i the junk rings 70.

The lower end of the bridging material mandrel 72 is. threadedl'y connected to a spring' or collet type latch 85 which includes the threaded box member 86 from which the springrngers 87- extend downwardly and grip arr'nuud` the enlargement 88 at the upper end of the bridge plug mandrel 90.V The spring lingers4 87 are held tightly about. thel enlargement 88 when conlined within the bore of the upper. bridge plug body section S4, but spring outwardly to'release the enlargement 33 when not so conned. Thus, themandfrel-,Qtlz-is releasably. secured to the lower endof theY bridging material Ymandrel 72 for the purpose of releas-V ing the bridging plug as presently described. t

Referring to FIGURES 4C and 4D, the bridging plug C includes. a plurality of bridgingV ribs. or strip likeele'- mentst94 secured to the upper bridge plug body section 5:14

at their upper ends and .to the bridge plug foot member 9?. Y

at their lower ends such as by disposing their upper ends in the annular groove 97 formed bythe head member 96' andjcounterbored portion 99 andtheir lower ends in the annular groove 161 formed in the bridge-plugvfoot member 98. Obviously, the bridging ribs 94 may be secured to orY carried b.y the bridging plug assembly C in any desired manner. The bridging plug mandrel is provided at its upper end with a series of wickers or threads ltlil which are engaged by the spring-like wedge member or latch ltZ disposed within the Vupper body portion 96:

As best seen in FIGURE 6, the spring-like wedge mem` ber 102 isa segmental nut to permit expansion and contraction for engaging and disengaging'the wickers lili) on the bridge plug mandrel 90 so that the head member 96 may automatically be latched and relatched in desired position.

The foot member 98 is restrained from downward movement by the nut 1Go threaded to the threaded lower endV to maintain the entire assembly in a generally centralized position within the tubing and the casing and are exible enough to pass through the tubing when lowering the bridging plug assembly in the tubing yet strong enough to centralize the bridge plug C when in the casing or open hole.

In operation, and referring to FIGURE l, the bridging plug assembly 16 is lowered from the surface, not shown, by means of the wire line 12 through the tubing 14 down into the casing 16 to a point where it is desired to bridge oi the casing, for example and as mentioned previously, to bridge off the lower depleted zone traversed by the casing 16 in order to produce from the upper zone 2Q.

Once the bridging plug assembly is in the desired position, the firing cap 341s electrically exploded which thereby explodes or ignites the explosive propellant 36. As best seen in FIGURE 5A, to which reference is now made, the expanding gases move through the duct S6, are retarded by the choke 69 until considerable pressure is built up in ring chamber 30, then pass through the choke 6%, duet SS and out the lateral passages 62 into the expansion chamber 52 and thus bearing against the shoulders 43 and 50 moving them outwardly relative to one another. This action, of course, moves the mandrel 54 upwardly which in turn moves the bridging material mandrel 72 (FIG- URE 4B) and the bridge plug mandrel 9 (FIGURE 4C) upwardly, the split nut or latch 132 expanding suiciently to permit upward movement of the bridge plug mandrel 90 relative to the upper bridge plug body member 34 of the junk ring section of the tool.

Referring to FIGURE 4C, when the mandrel 72 is moved upwardly suliciently to move the collet or spring type latch 85 upwardly into the release spacers 78, the Spring fingers 87 move outwardly and release the enlargement 38 and thus the bridge plug C.

As best seen in FIGURE 5B, the collet type latch S5 is shown released from the enlargement S3 on the upper end of the bridging plug mandrel 96.

Referring again to FIGURE 4D, as the bridge plug mandrel is moved upwardly relative to the lower body section 84 of the junk ring section of the tool, the ribs or spring bridging members 94 are compressed and expanded due to the lower bridge plug body member or foot 98 being moved upwardly by the nut 105 toward the upper bridge plug member 84 and its counterbored portion 1&9 into which head member 96 (FIGURE 4C) is threadedly secured.

As previously explained, the lock ring 102 expands to permit this upward movement but once the bridge plug mandrel 90 has moved upwardly its full stroke, the lock ring or latch 1%2 engages the wickers 160 and thus maintains the bridge plug in expanded position.

The initially expanded position of the bridge plug is best illustrated in FIGURE 2, to 'which reference is now made. At the same time the bridge plug is being expanded, and once it is released, the junk rings 7G are released and slide downwardly oi the junk ring or bridging material mandrel 72 and provide a coarse bridging material on top of the expanded bridge plug 92. The setting assembly A and bridging material assembly B may then be removed from the well by raising lthe wire line 12.

-ln FIGURE 3, coarse bridging material, for example, gravel, marbles and the like 114 are disposed on top of the junk rings 70 and sand 115 and a short section of sealing material 116, such as cement, Various plastics, resins, chemical Sealers and the like, are provided above the coarse bridging material 114.

Preferably, the sealing material 116 is disposed or placed in position by means of lowering the dump bailer 118 through the tubing 14 by means of the cable 120. While any desired dump bailer may be used, the dump bailer disclosed in my copending application Serial No. 647,383, tiled March 30, 1957 is particularly useful for dumping sealing material, such as cement, through tubing.

Also, the bridging material 114 and 115 may be so placed in position although, if desired, it may be dumped into the tubing 14 at the surface and permitted to fall down the tubing into position.

- Once the well has been bridged, the upper zone may be perforated, as at 21, to produce this zone. Thus, the lower depleted zone 13 previously producing through the perforations 19 is bridged oi and the upper zone is then produced without removing the tubing 14.

While the bridging material section of the tool is highly advantageous in that it reduces the number of trips and the time required for completing the bridging of the well below the casing, it will be understood, that this section may be omitted and that the initial bridging material placed upon the bridging plug may be placed in position separately from the setting of the bridging plug.

Also, it should be noted, that while the explosive cap 34 is detonated electrically, which requires the use of an electric conductor wire line, this may be done mechanically or otherwise, in which event a cable may be used to lower the tool into the well, it only being necessary to drop a go-devil or some other device to engagea striker for striking a percussion type cap to ignite it. Also, if desired, the bridging plug may be set mechanically.

It is also noted, that the bridging plug assembly is suitably packed oi and the wash ports 1'22 (FIGURE 4B) are provided in the body section 63 to permit movement of the head member 74 within the body section 68 even though well fluid is within. Advantageously, the retarding action of the head member 74 serves as a piston driving well fluid out of the wash ports 122.

Preferably, the bridging plug C and centralizer D are made of an easily-drillable material, for example, aluminum. Also, if the bridge plug C fails to set, it merely drops to the bottom of the well and can be easily drilled out. Preferably, the setting tool A and retrievable parts of the bridging material section B are made of a material, such as steel, so that they may be used again.

lt would be advantageous to bridge and seal the well all in one trip in order to avoid the time and expense of separately dumping the sealing material. The present invention includes and contemplates such an apparatus and method.

Referring now to FIGURE 7, where the reference letter a has been added to character numerals to designate like parts of FIGURES l-6, inclusive, the dump bailer 11Sa is combined with the bridging assembly 10a, only a fragment being shown in FIGURE 7, by threadedly securing the threaded lower end 120 of the dump bailer 118:1 into the threaded upper end of the setting section body 24a.

The dump bailer 118i: includes a generally elongate tubular body 122 which includes in its upper portion the chamber 124 for retaining the sealing material 116a, such as cement and the like as previously mentioned, a cup or closure member 126 is releasably secured to the body 122 to form the lower closure of the chamber 124. A shearpin 128 releasably secures the closure or cup-like member 126 to the body 122.

Disposed in the lower portion of the generally tubular body 122 are a plurality of elongate windows 130 through which the sealing material 116e is dumped as later' explained.

While not shown, a cable connection, such as the cable connection 22 (FIGURE 4A) is used to connect the upper end of the body 122 and the electric conductor 26a extends downwardly through the chamber 124, through the packing or seal member 132 and gland nut 134, through the window section 13G and to the electric contact 23 (FIGURE 4A). Thus, the bridge plug is set as previously described.

Means, not shown, are provided to release the closure 126, for example, a ring chamber and arrangement such as utilized in the setting tool A which is actuated on reverse polarity of the electric conductor 26a which applies i downward force against the closure cup 126 shearing the shear pin 128.

Noi more detail of the specic dump bailer is given as any dump bailer having releasable means for dumping they sealing material may be used and the dump bailer, as such and by itself, does not constitute the present invention. For example, my copending application, Serial No. 647,383, previously referred to, discloses details of the dump bailer 118a.

In use, the bridge plug assembly 1i) including the dump bailer. 118:: is lowered on an electric wire line such as indicated at 12 in FIGURES l and 2. rIhe bridge plug C is setas previously described and then the dump bailer 11851 is actuated to release the closure cup 126 so that it falls to the position illustrated in FIGURE 8. The sealing material 116a, such as cement, is thus dumped into the casingV 16a to form aV sealed area such as shown in FIGURE 9. The dump bailer 113e and the setting as sembly A may then be removed from the well. By the combined apparatus the bridging and sealing are advantageously accomplished ina single trip in the well and may be used through tubing for setting in the casing below the tubing, or in the casing without tubing.

The method of the invention has been touched on in the description. of the operation of presently preferred apparatusA according to the invention in one of its many applicationsY and uses. One aspect of the method of the invention comprises, lowering a bridging plug through tubing, setting the bridging plug in the casing below the tubing, providing bridging material on top of the bridging plug and providing a sealing material such as cement, plastic or other sealing agents on top the bridging material. Preferably, in the method of the invention, a bridging assembly Such as previously described is used. It will bev understood, however, that other bridging plugs or assemblies rnay. be usedin the method of the invention, it only beingy necessary to provide a` bridging plug which is retractable suiiiciently so: that it may be lowered through tubing'and expanded to engage the casing below the tubing. Also, any desired bridging materials may be disposed on the bridging plugand these may be provided either by lowering them or dropping them from the surface or by lowering them through the tubing in a dump bailer.

For added strength, the method contemplates setting the cement column at a location So that it will be in perforations or opposite a collar. locking and sealing properties.

It should be noted that no rig is required for bridging thewell by the present apparatus and method and that` ordinarily only about twenty-four hours cement setting time is required after dumping the cement. Other cementitious materials may be used which require shorter or longer setting times.

The` apparatus and method. of .the invention mayA be used' for other purposes, such as in squeeze cementing an upper formationit is desirable to seal olf a lower formation to protect this lower formation from cement contamination resulting from the squeeze. In the event it is desired to seal olf the formation 2t) and produce from theiformation 18 (FIGURES 1 3), and referring now to .FIGURE 9, theA bridging plug C is set slightly below the formation 20, say about two feet. Bridging material or aggregate such as gravel 114 and finer material 115 is thendumped on top of the bridging plug C and junk ringsv 70`up to about the lowest perforation 21. Cementitious material 116 is run in the dump bailer 118 and dumped so thatonly theperforations 21 in the section of the casing adjacent the formation 20 are covered; The dumpY bailer 118 is then removed or the wire line is packed off aty .the surface. Flow pressure is then applied to the tubing with conventional means at the surface, not shown. This places a pressure squeeze on the cement, which has not yet set, and drives it back into the perforations 21 as shown in FIGURE l0.- This is allowed to` set for a short period of time, say about one This gives improved hour for oil` well cement now in use, and the pressure is then removed. The time allowed is such that the cement is set solidly enough and dehydrated in the perfo-V rations 21 to a point that when the bulk of the cement in the casingl is washed out it will not wash out of the perforations.

Upon removal of the pressure, after completion of the low pressure squeeze, the cement above `the plug is circulated out of the hole, leaving the cement in the perforations in a set high strength condition thus sealing olf the perforated zone 20.

The bridging plug may then be knockedV to bottom with sinker bars or other means or it may be left in place since the oil from formation 18 will ilow through the ribs of the bridging plug. Y

Preferably, when using the bridging plug lfor squeez-V ing, the bridging plug is set in a collar, such as indicated at 17, so that the ribs will bulge out into the collar 17, thus giving greater resistance to slippage. Y

I-f desired, the combined dump bailer bridging assembly illustrated in FIGURES 7 and 8 may be used in connection with this method. Y

Thus, the present apparatus and method maybe used for any and all bridging purposes. Also, the bridging plug may be set in casing Without running throughtubing when desired. It may also be set in an open hole when desired for the purpose of supporting test tools and the like. It is noted that the bridging plug itself holds no fluid pressure from either direction but simply provides a ybridge which serves as a baseV for a column of cementitious or other sealing material to provide the desiredv seal.

The present invention s therefore wellsuit and. adapted to attain the objectsv and ends and has the advantages mentioned as well as others inherent therein.

While only presently preferred and representative embodiments of the apparatus Lof the invention have been given for the purpose of disclosure, numerous changes inv details and arrangements of parts` of the apparatus of the invention as well as uses thereof will suggest themselves to those skilled in the art which are Vencompassed within the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. A bridge plug assembly comprising, a bridge plug including a mandrel, a plurality of generally longitudi# nally extending bridging ribsV disposed about the mandrel, a iirst end of each of said ribs secured to the mandrel, the second end of each of saidlbridging ribs slidably disposed about the mandrel, releasable latch means latching the second end of each rib on the mandrel thereby'preventing sliding movement on the mandrel, means Von the mandrel engageable by thek latch means for latching the second ends on movement of said first and secondends toward each other, and setting means including means for moving said iirst ends'toward' said second ends thereby moving the intermediate portions of said ribs outwardly.

2. A bridging plug assembly comprising, a bridge` plug including a bridging plug mandrel, a plurality of generally longitudinally extending bridging ribs disposed about the mandrel, the 4lower end of eachy rib secured to the mandrel, the upper end of each of saidV bridging ribs being slidably disposed on the mandrel, releasable latch meansreleasably latching the upper ends to the mandrel, slip r'neans on the mandrel engageable by the latch means for latching the upper ends on movement of the lower and upper ends toward each other thereby setting the bridging ribs in bridging position; a setting assembly including a bodyv disposed above-the bridge plug, a setting mandrel slidably disposed in the setting body, said body forming a cylinder about a portion of the setting mandrel, aV piston on the setting mandrel and disposed in said cylinder, a iring chamber carried by the piston, a duct leading from the ring chamber into' the cylinder whereby ignition of an explosive in the tiring chamber and expanding gases therefrom serve to move the piston upwardly relative to the body thereby raising the setting mandrel and the bridge plug mandrel; and releasable connecting means connecting the setting mandrel and the bridge plug mandrel constructed and arranged to release the mandrels upon upward movement of the bridge plug mandrel relative to the body.

3. The bridge plug assembly of claim 2 where tne releasable means comprises an enlargement on the upper end of said bridge plug mandrel and includes spring latch elements extending from the setting mandrel disposed about said enlargement and a releasing chamber in the body above said releasable connection whereby upon upward movement of said mandrels said spring latch elements move into the releasing chamber and are released.

4. A bridging plug assembly comprising: a bridge plug including a bridge plug mandrel, a plurality of longitudinally extending bridging ribs disposed about the mandrel, the lower end of each rib secured to the mandrel, the upper end of each rib being slidably disposed on the bridge plug mandrel, releasable latch means latching the upper ends to the mandrel, said latch means arranged to relatch upon upward movement of the mandrel relative to the upper ends thereby setting the bridging plug in bridging position; a setting assembly including an elongate body disposed above the bridging ribs, a setting mandrel slidably disposed through the body, a piston cylinder formed in the body about the setting mandrel, a piston disposed on the setting mandrel in the cylinder, a ring chamber carried by the piston, ducts leading from the tiring chamber into the cylinder whereby ignition of an explosive in the cylinder and formation of expanding gases causes movement of the piston in the cylinder thereby moving said setting mandrel; a bridging element assembly including a bridging element mandrel secured to the setting mandrel, a plurality of bridging elements disposed about the bridging element mandrel, releasable means holding said bridging elements about said mandrel releasable upon release of the bridging element mandrel and the bridge plug mandrel, and a releasable connection connecting the lower end of said bridging element mandrel and the upper end of said bridge plug mandrel, said releasable connection arranged to be released upon upward movement of said mandrels relative to said setting assembly body, whereby upon ignition and expansion of said explosive, the bridging plug is set, the setting assembly and bridging element assembly are released and the bridging elements fall downwardly on to said bridging ribs.

5. The bridging plug assembly of claim 4 in which the releasable connection comprises an enlargement on an end of one of the bridge plug and bridging element mandrels and spring fingers extending from the other of said mandrels disposed about the enlargement, means normally confining said iingers, and a releasing chamber of extended internal diameter whereby upon upward movement of said mandrels and movement of said spring iingers into the releasing chamber permits expansion of said releasing fingers and release of said releasable connection.

6. A bridge plug assembly comprising a bridge plug including a mandrel, a plurality of generally longitudinally extending bridging ribs disposed about the mandrel, a first end of each of the ribs secured to the mandrel, the second end of each of the ribs being slidably disposed about the mandrel, releasable latch means on said mandrel adjacent the second end of said ribs for latching the second ends on the mandrel on axial movement of said second ends toward the rst ends, setting means for moving said rst and second ends of each of the ribs toward each other thereby bending the ribs and moving the intermediate portions of the ribs outwardly, releasable connecting means connecting the mandrel to said setting means, and means releasing said connecting means on a predetermined movement of the mandrel.

7. A bridging plug assembly comprising a mandrel, a plurality of generally longitudinally extending bridging ribs disposed about the mandrel, the rst end of each of the ribs secured to the mandrel, the second end of each of the ribs being slidably disposed about the mandrel, releasable latch means latching the second end of each rib on the mandrel, means on the mandrel engageable by the latch means for latching the second ends on movement of said rst and second ends toward each other, a plurality of bridging elements releasab-ly carried by the mandrel above the bridging ribs, setting means for moving said iirst and second ends of the ribs toward each other thereby moving the intermediate portions of the ribs outwardly, releasable connecting means connecting the mandrel to said setting means, and means releasing said connection means, mandrel and bridging elements, on a pre-determined movement of the mandrel.

8. The bridging plug of claim 7 where the bridging elements comprise segmental junk rings.

9. A bridging plug assembly comprising: a bridge plug including a bridge plug mandrel, a plurality of longitudinally extending bridging ribs disposed about the mandrel, one end of each of said ribs secured to the bridging plug mandrel, the second end of each of said ribs slidably disposed on the bridge plug mandrel, releasable latch means latching the second ends to the bridging plug mandrel, said latch means arranged to relatch upon movement of the bridging plug mandrel relative to the second ends thereby setting the bridging plug in bridging position; a setting assembly including an elongate body disposed above the bridging ribs, said body including a cylinder having an open end, a piston disposed in said cylinder, a setting mandrel slidably disposed in the body and connected to the piston, a firing chamber adjacent the piston, a passageway leading from the iiring chamber from one side or the piston to the cylinder on a second side of the piston whereby creation of an expanding gas in the tiring chamber causes movement of the piston in the cylinder thereby moving said setting mandrel until said piston moves out of said open end; a bridging element assembly including a bridging element mandrel secured to the setting mandrel, a plurality of bridging elements disposed about the bridging element mandrel, releasable means holding said bridging elements about said mandrel, said releasable means being releasable upon release of the bridging element mandrel from bridge plug mandrel, and a releasable connection connecting the lower end of said bridging element mandrel and the upper end of said bridge plug mandrel, said releasable connection arranged to be released upon a predetermined upward movement of said bridging element and bridge plug mandrels relative to said setting assembly body whereupon upon expansion of a gas in the tiring chamber the bridging plug is set, the bridging element mandrel and the bridge plug mandrels are released from each other, the bridging elements fall downwardly on the said bridging ribs, and said piston moves out the open end of the cylinder releasing the gas from the firing chamber.

References Cited in the iile of this patent UNTTED STATES PATENTS 1,676,785 Lewis July 10, 1928 1,979,802 Kinley Nov. 6, 1934 2,229,325 Greene Jan. 21, 1941 2,618,345 Tucker Nov. 18, 1952 2,621,744 Toelke Dec. 16, 1952 2,701,615 Riordan et al Feb. 8, 1955 2,708,973 Twining May 24, 1955 2,728,395 Howard Dec. 27, 1955 2,735,496 Wilson Feb. 21, 1956 2,800,185 Teplitz July 23, 1957 2,815,817 Conrad Dec. 10, 1957 2,831,540 Huber Apr. 22, 1958 2,911,048 Dublin et al. Nov. 3, 1959 NETE@ STATES PATENT @FFCE ee'rmmr e: @brew Patent Na, 390641.C 734 November 2()Q 19362 Leser WLv Toelie It is hereby certified 'that error appears n the above numbered patentl requiring correction and that the seid Letters Patent should read as corrected below.

Column i? line 553Q for 9' column 2 column line 74V e met/10e? ef reed line 7D. fer Ueherer afer March 30g Column @Je e@ en eppareue read eebarac'er me; '195W' insert e new ine O beere "me-ans inserer, e

Signed and sealed ibis 2nd day of July i963@ (SEAL) Attest -ERNEST W. SWDER Attesting Officer DAVID L. LADD Commissioner of Patents

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