US2643722A - Hydraulically inflatable packer - Google Patents

Description

June 30, 1953 J. LYNES ET AL HYDRAULICALLY INFLATABLE PACKER 5 Sheets-Sheet l FIGZ ATTORNEYS FlG.l.

7747 r 7' a mwuw w mix M A m m b. 7 I. Z 6 n rom A M m 5 W June 30, 1953 J. LYNES ET AL 2,643,722

HYDRAULICALLY INFLATABLE PACKER Filed Feb. 26, 1948 6 Sheets-Sheet 2 35 J.D.GARDNER JOHN LYNES cs0. H. ALLEN Z INVENTORS ATTORNEYS June 30, 1953 J. LYNES :1- AL 2,543,722

HYDRAULICALLY INFLATABLE PACKER Filed Feb. 26, 1948 6 Sheets-Sheet 3 FIG.5

JO LYNES ca LEN J.D.GA NER INVENTORS I BY ATTORNEYS J. LYNES ET AL 2,643,722

HYDRAULICALLY INFLATABLE PACKER 6 Sheets-Sheet 4 June 30, 1953 Filed Feb. 26, 1948 JOHN LYNES GEO.H.ALLEN J. D.GARDNER INVENTOI5 ATTORNEYS June 30, 1953 LYNES ET AL HYDRAULICALLY INFLATABLE PACKER 6 Sheets-Sheet 5 Filed Feb. 26, 1948 .vww w w @PMR W Y E N m H A J. LYNES ET AL HYDRAULICALLY INFLATABLEPACKER Jl me 30, 1953 s Sheet-Sheet 6 Filed Feb. .26, 1948 Z w m 4 4 l l 4 4' 1 4 4 6 4 8 Z m S R E EM N N Y DW NHA H OED. GJ

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By 6' caulk ATTORNE Patented June 30, 1953 UNITED STATES PATENT OFF-ICE HYDRAULICALLYHVFLATABLE PACKER John Lynes, George H. Allen, and Jimmy D. Gardner, Houston, Tex., assignors to Lynes, Inc., Houston, Tex., a corporation of Texas Application February 26, 1948, Serial No. 11,214

11Olaims. L1

The invention relates to an inflatable packer which has variousand sundry applications, -but one of the principal-functions .of which is-to;pro vide aiseal-or seals in a well bore.

Thepresent invention is specifically-directed to the --creatin of animpervious reinforcing sheathwhich'forms the-foundation=of .the packer in.=such a mannerthat the inflating'pressure will be confined even-though it may involvetheinflating of the packer with tremendous pressures.

"The invention involves an arrangement for layingwires on a helical lead to create such impervious sheath and'to a -means for anchoring the ends-of thesheath and sealing the .inside thereofisoas torresist not only theinternal inflatingpressure but the :externalpressures which-are beingzpackedso as to-maintainaseal with the earth formation or the pipein which the packer isadisposed.

It isroneiof the .obj ects'of the invention toprovide a hydraulically inflatable packer-made 'up of resilient :material with suitable reinforcing of 'high tensile strength so'that the reinforcing willimaintain animpervious s'heathito confine the resilient material in'resisting the pressures applied.

Another-tobject ofthein'vention is'toaprovide ameiriforcing 'sheath fora hydraulically inflatable packer so that a plurality of layersof rein forcing strands will efiect .relative movement with respectto the strands'in the same'or other Iayers in such:manner that thestrands will remain in strand-to-s'tran'd contact to maintain an impervious sheath in all positions o'f'thepacker from fully deflated to maximum working diameter.

Another object is to construct a packer to provide a sealing characteristic at 'a predetermined diameterby laying the reinforcing strands with a predetermined lead which is afunctionof the-ratio of deflated toinflated-diameters.

Anotherobject'is to determine the inflated diameter at which a hydraulic packer-will provide cylindrical sealing by predetermining the helical lead of the strands of the reinforcing sheath therein.

Another object of the invention is to provide a strand reinforced, hydraulically inflatable packer wherein the components of force tending'to expand the packer are predetermined by the helical lead of the "strands of reinforcing material so that the-maximum effectiveness inmaintaining a sealcan be determined. A

Another 'object of the iinvention is to provide a hydraulically inflatable packer which may be 2 utilized to provide either or both a-cylindrical contact seal or a shoulder contact seal withthe area being packed.

.Still another objectof the invention-is to tprovidea hydraulically inflatable packer which will seal either with a relatively immovable cylindrical surfaceor which may apply such a pressure to asurface to be-sealed so-as todeformsuch surfaoeand provide a shoulder contact for maintaininga seal at the deformedsurface;

Still-another object-of the invention'isitoprovide a =means for laying strands for the reinforcing of a hydraulically inflatable tpacker in such a manner that the strands will -maintain an impervious sheath while expanding from normal to a predetermined expansion which' is -a function of the arrangement of such strands.

:Itis also-an objectto provide-a-packer capable of expansion beyond 'a diameter where the reinforcing strands provide an impervious-sheath.

Still another object of the invention :is 'to provide an anchor :for the ends of :a reinforcing sheath for hydraulically inflatablepackers.

Another object of the-invention-is toprovide a mechanism for anchoring-.a'strandedreinforcing sheath for --a hydraulically inflatable packer wherein a tapered wedge increases :thefrictional grip on-the =sheath when. the strands thereof are subjected ito'tensile stresses.

Still 951110131161 .obj ect of .theinvention is to "provide ;a reinforcing assembly for hydraulically infiata-blepackers wherein a pluralityof layers of strands are laid with a lead 'such'thatupon' expansion .of the packer that 'two contiguous layers of strands'will'remain instrand-to-strand contact while consolidating themselves 'into a single :composite layer made up of alternate strands from such two contiguouslayers.

Another object of the invention is to provide a reinforcing sheath for packers wherein a' pluralityof layers of reinforcing'strands are crosswrapped so as to resist the torque tending to unwrap the sheath upon the inflation of the packer.

Another object is to'provide a built-up inflatable packer for wells-comprising the combination of a supporting sheath with means for anchoring the ends thereof and an inside sealing tube and, an outer sealing covering.

A still further object 'for the detailed fabrication o'f one'form of thepackeris'to providetwo layers of reinforcing strands, each having the sa'm'numberof strands-and laid withthe-same helical :lead in lcombination with two companion layers which are cross-wrapped with respect to the first two layers so that upon expansion of the packer the strands of the first two layers alternate with each other to provide an impervious sheath over which a second composite sheath made up of alternate wires of the second pair of cross-wrapped layers will be provided where such second composite layer may or may not provide an impervious sheath.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accom panying drawings, wherein:

Fig. 1 is a vertical sectional view of a hydraulically inflatable packer and tool assembly therefor with the packer shown in deflated position;

Fig. 2 is a vertical sectional view of a hydraulically inflatable packer and tool assembly therefor with the packer shown in inflated position.

Fig. 3 is a side elevation of the packercon struction with certain parts and layers of reinforcing strands broken away to illustrate the manner of laying the strands.

Fig. 4 is a broken transverse sectional view taken on the line 4-4 of Fig. 1 and illustrating the control pipe and the deflated arrangement of the inner seal tube, reinforcing sheath, and the outer elastic covering.

Fig. 5 is a broken transverse sectional view taken on the line 55 of Fig. 1 and illustrating the arrangement of the control pipe; the inflated liner seal, reinforcing sheath, and the outer elastic covering which may or may not constitute maximum inflation diameter, depending upon the type of fabrication of the packer as to the angle of lead.

Fig. 6 is an enlarged transverse sectional view of the arrangement of the reinforcing strands as seen in Fig. 4.

Fig. '7 is a vertical sectional view illustrating one form of anchor head for retaining the ends of the sheath-construction.

Fig. 8 is a vertical sectional view illustrating one form of anchor head for retaining the ends of the sheath construction utilizing a tapered wedge, frictional grip construction.

Fig. 9 is a broken sectional view of one type of packer expanded against a relatively rigid earth formation.

Fig. 10 is a side elevation of another type of packer expanded against an earth formation which has been crushed or deformed in obtaining and maintaining a seal by a buttress or shoulder seal formed by the expansion of the packer into the formation.

I In Fig. l the mandrel 2 is an extension of the operating pipe by which the packer is lowered into and manipulated in the well bore. The packer assembly 3 is mounted on this mandrel and may be made up by a suitable structure, but is here illustrated as including the upper cap 5 which is in the form of a metal member having an axial bore providing an internal passage 6 therethrough and through which the mandrel 2 extends. The wall of the passage '6 is recessed at I to receive a packing ring 8 which may be in the form of a pressure seal or O rin to maintain a seal between the bore of cap 5 and the mandrel. The cap is internally enlarged at II) and the enlarged bore portion is threaded at H in order to receive the annular head I2. This head has an upstanding threaded annular extension I3 which is engaged with the threads II. This extension is sealed by a packing ring l4 disposed in the recess l5 in the wall of the enlargedarea or chamber H) which bears against 23 'of the packer reinforcing sheath 24 is to be anchored The anchoring of the packer sheath end 23 is importantbecause such anchoring must resist tremendous stresses.

It will be noted from Fig. '7 that the end 23 of the reinforcing strands 25 of the sheath 24 are securely gripped between the skirt [9 and the sleeve 20 to resist an axial and radial pull and torque on the strands when the packer is expanded, as seen in Fig. 2.

The detailed construction and operation of the sheath 24 will be later described.

It seems obvious that the ends 23 of the strands 25 may be anchored in any suitable manner but as seen 'in Fig. 7 the layers of wire have been inserted into the chamber 22 and then the inner skirt has been subjected to outward radial distortion so as to compress the ends 23 of the wires or strands 25.

One mode of such compression is to provide the internal sleeve 20 of a smaller diameter than shown in Fig. 7 so that the passage 18 through the head as continued through the sleeve 20 will be of smaller diameter. This would create the lower end of the chamber 22 as being of greater radial width than as shown within the bottom of the head portion so that the ends 23 may be inserted in the chamber with ease. The skirt 2!] may then be expanded radially in any desired manner so as to clamp the ends 23 between the skirt [9 and the sleeve 20. It will be noted that the skirt I9 is somewhat heavier than the skirt 2!! so as to serve as a support against which the strands 25 and the skirt 20 may be pressed.

A suitable internal jig or mandrel could be forced by suitable pressure through the skirt 20 to efiect such radial expansion to clamp the strands. A metal ball could be forced through the passage I8 of the head I2 and effect the expansion of the skirt 20 where the sleeve is of smaller internal diameter than the passage 18 as described above.

-The skirt i9 is provided with internal ribs 30 which are spaced axially along the inside Sillface thereof and the external periphery of the skirt 20 is provided with outstanding ribs 3!. These ribs may be arranged in pairs as shown with a slight depression 32 between the ribs of each pair so that the ribs will obtain a greater frictional grip with the strands 25 when the skirt 20 is expanded. The inner skirt 20 is somewhat shorter than the outer skirt 19 so as to avoid any abrupt bending or undue flexing of the various parts which make up the packer sleeve when the packer moves to expanded position. Also notice that the inside lower edge of the outer skirt I9 is beveled at 34 to facilitate such expansion.

An internal sealing tube 35 of resilient or elastic material is arranged to be slipped through the opening is in the head l2 and is of a length to extend into the lower head 40 which is the same as the head-l2 except-that it is inverted so that the-skirts-l9 and 20 are upstanding and, as seen in Fig. 2, this sealing. tube forms the surface 4| against which the inflating pressure will bear so as'to force the tube 35 to expand such tube against the wall of the passages I 8 in the upper and lower heads l2 and! and also against the inside surface of the skirt-2l3 to automatically seal the liner tube 35 in position. v The mandrel 2, asseenin Fig. 1, extends through this. internal sealing tube 35. If desired an adapter liner 36 may be arranged to extend from the end of the skirt 20 on the head l2 throughout-the inside length of the packer sleeve to abut against. the

similar skirt 20 in the lower head 40, as seen in Fig. 1. A bore 42 will be thus provided when the packerisuninflated, as seen in Fig. 1. y

The reinforcing strands 25 makeup asheath 24 of reinforcing mater-ial which will-confine eitherorboth the inner sealing tube 35 andthe adapter liner 36 so as to; confine the pressure used in inflating the. packer.

Thearrangement, fabrication, and positioning of this reinforcing metal sheath 24 will be later described.

An external easing or cover 4.5 encloses the sheath 24 and overlies the skirt 19- terminating in a feather edge 46 on the. bevel 41 ofthe head [2 to provide a smooth external surface. This covering is preferably elastic to such. an .extent that when the packer is deflated that :thecovering will return the parts to the position shown in- Fig. 1.

In order to provide:for;hydraulic. seals for the inner sealing tubal-5. and the :outside casing 45, an equalizing port 48 has :been provided in the head l2 at the junction. of the. skirt [9 and a similar port 49 is provided at. the, junction ofthe skirt 2.0 with the head 12.. Both of these ports are connected intothe chamber 22. beyond the ends 23 of the strands -25.

Particular attention is directed tothe annular groove 50 on the outside of the sleeve underneath the end of.the casing'45 and a similargroove 5} the. Wall of the passage 18 in. the head at the port. 49-.. In'this mannerthe external pressure against the casing 455 and the internal pressure against the. tube 3.51wi1l cause the material. thereof to fit into such grooves 50 and filctoform hydraulic seals. andpre vent any leakage into the chamber 22 and the strands 25 of the sheath 24.

In this manner any initial-leakage into-the chamber .22 will be equalized. and a seal mai-n tained by the predominant pressure regardless of Whether it is internal or external.

As. seen in. Fig. 1 the internal inflating pressure will be applied. from the surface through the operating pipe. which. is connected to the mandrel 2 so; as to flow through. the openings 52 into the internal chamber 53 formed inside the When the desired inflation and seal hasbeen;

obtained by expanding the packer; the mandrel 2- will be moved tothe position where the opening's 52 are beyond. the seal 8 in the cap so as. to

lock the hydraulic pressure within the. packer chamber 53.

Figs. 1 and 7 show the headand-skirts l9 and 20 as a single support member which has. been found to be satisfactory but other forms may be employed. 1

Fig. 8 shows a modified arrangement of the end support member for anchoring the ends 23 of the strands in the forming of the sheath 24. The head l2 has been modified so that s the skirt 19 has an internall tapered face so as..to provide a tapered bowl Bl. A wedge collar 62 which may have a locking taper has been inserted into thebowl 61 to expand the ends 23 of the strands so as to seat in the bowl 6|. The tapered bowl BI and the wedge 62 form a chamber which is the equivalent of the chamber 22 of Fig. 7. The taper increases the grip due to any pull on the strands.

The extension l3 of Fig. 1 is shown in Fig. 8 as a separate portion threaded at 63 into the head I2 and is so arranged that the lower end 64 thereof will abut the Wedge collar 62 or slips which serve the same purpose as the inner skirt 20 of Fig. 1 to securely clamp the ends 23 of the strands 25. The end 64 and the upper end of the wedge or slips 62 may also be beveled so as to provide the internal groove 5! and notched to obtain the function of the passage 49, in Fig. 7. A collar 10 is disposed about the sheath 24 belowthe end ofthe skirt l9 so as to confine the strands of the sheath and abut against the lower end H of the skirt I9 to form a support for the outer casing 45. This end H may be beveled to form with'the collar 10 the equivalent of the groove 50 in Fig. '7.

The port 48 extends through the skirt I9 so as to equalize the pressure between the chamber 22 and the groove 50 beneath the casing With this construction the Wedge collar 62 may be securel y forced and held in position to anchor the ends of the strands.

The detailed arrangement and the method of fabricating the wires or cables 25 of the reinforcing sheath 24' is best seen in Figs. 3 4, and 5 where the enlarged broken arrangement of the parts shows the casing 45 as having been broken away to reveal the sheath 24 which is made up of the strands 25 whose ends 23 have been anchored as described.

The sheath 24 in the form which will be here described is illustrative only and not a limitation of the construction.

The sheath will be made up of an inside layer A of strands laid side by side with a second layer B of strands thereover, the strands of the layers A and B being laid with the same lead in the same direction. The two layers A and B may have the layers C and D- lai'd thereover with the lead thereof wrapped in a direction counter or oppositeto layers A and B. Thus, if the layers A and B are clockwise, layers C and D will be counter-clockwise, as seen in Fig; 3'. cross wrapping the torque on the packer, due tothe pressure stresses: tending to unwind the strands, will. be balanced. because of the opposite helical leads. 1

The wrappings. of strands in the layers A, B, C, and D will: thus provide a very strong impervioussheath capable of expansion while'resisting both internal and external stresses.

Inside of the layer A. will. be the internal sealing tube 35. The section. on. the line 4-4 of Fig. 3 is seen. in. Fig. 4 where the packer is uninfiated illustrating the arrangement. of the parts With Such just described.' The parts are in order reading from the inside outwardly, the mandrel 2, the inner sealing-tube or liner 35, and then thelayers A, B, C, and D of reinforcing strands, and finally the outer covering or casing 45.

The theory and purpose of the sheath 24 is to form an impervious reinforcing sheath to confine either or both the adapter liner 36 and the inner sealing tube 35 in such manner that the tremendous hydraulic inflating pressure can be sealed andconfined by the sheath 2% because the sheath thus formed will prevent the extrusion of the material of the inner sealing tube or adapter.

The particular arrangement and construction of the reinforcing sheath forms one of the essential features of the arrangement and may be de scribed as follows:

The layer A made up of strands or wires,.strap or cable 25, will be formed by laying the-strands side by sides on a Suitable support along a helix in such a manner that the strands will contact each other side by side to form a sheath or sleeve. When a complete cylinder is formed of the strands making up the layer A, then the layer B will be laid thereon with the strands of the layer B being laid crest to groove of the strands in layer A with the same number of strands in the layer B as have been laid in the layer A. Thus, the strands of the layer B may not be quite in side-by-side contact because they are laid on a circle whose diameter is greater by the distance center-to-center of the strands of layer A to the strands of layer B disposed in the groove A formed by the adjacent strands of the layer A.

In other words, the diameter of layer B as seen in Fig. 4 is larger, or greater than the diameter of the layer'A, by a distance which is slightly less than twice the diameter of the strand because the strands of layer B are seated in the grooves A as seen in Fig. 4..

The layers C and D will be laid in the same manner as the layers A and B respectively except that the lead will be in a counter direction and in this manner any torque in the packer due to inflation which is tending to unwrap the reinforcing strandsis balanced by the layers A and B, opposing the layers C and D.

It seems obviousthat for instance if the packer had only one layer A of wires and such layer A was inflated from its normal diameter. as seen in Fig. 2, to, say twice its normal diameter, as seen in Fig. 4, that the reinforcing wires of the layer A would be expanded to form a layer of.

much greater diameter than the normal diameter of the layer A as seen in Figs. 1 and 4. For instance, if the inflated diameter were twice the deflated diameter then there would be a space between each of the wires of layer A which would approximate the diameter of one of the wires. The groove A would thus widen to create such space. The inner liner or tube would then be unsupported and might be forced between the adjacent wires into such space or widened groove A and a rupture of the packer might occur. With the present arrangement, however, with the multiple layers A and B, etc. laid in the same direction when the layers begin to expand and the grooves A begin to widen, the wires of layer B, both already laid in the groove A formed by the adjacent wires of layer A, will creep into the groove A as layers A and B expand and the groove A between the wires of layer A enlarges. In other words, the wires of layer B automatically move into the grooves A between adjacent wires in layer A. The B wires are already started in this position by having been laid in the groove A, and due to the fact that there are the same number of wires in layer B as have been provided in layer A.

It seems obvious that as the packer is inflated and the layer A is doubled in diameter that the wires of layer B will have been moved into the grooves or spaces A between the wires of layer'A to form a composite layer of wire made up of alternating wires A and B, forming the first or internal layers of the sheath 24 in expanded position as seen in Fig. 5.

This composite layer indicated at X, as seen in Fig. 5 is made up of alternate A and B wires. The layer X, therefore provides the first layer of the sheath 24 so as to completely confine the internal sealing tube or liner 35 or adapter 36 as the case may be. 3 1 p The layers C and D will be laid with an opposite helical lead as regards the layers A and B and the composite layers X. The desired number of wires will be provided in the layer 0 and the same number in the layer D so that when the packer is expanded the next composite layer Y or the sheath 24, as seen in Fig. 5, will be made up of alternate wires 0 and D in exactly the same manner as described in the creation of the layer X. Of course the layer Y cannot have the wires laying crest to groove with the wires of the layer X because layer Y is of an opposite helical lead;

It is not intended by the foregoing description to limit the invention as to the diameter, size, strength, or number of the various wires and strands. Such features are mechanical expedients which may be in the form of engineering design to accomplish the theory and method heretofore disclosed.

Packers may be fabricated where a composite D. For instance Fig. 6 may be an illustration of an exceptionally strong sheath 24 adapted to" withstand tremendous pressure where thestrandsin the layers A, B, C, and D are each made up of a pro-formed cable such as where the cable 75 is in turn made up of seven smaller cables 16 where each of the smaller cables 16 is inturn made up of seven wires Tl. 'Fig. 6 is intended to illustrate on a. magnified scale the metal-to-metal contact between the strands of the layers A to form the groove A. The strands of the layer B are arranged in crest-to-groove assembly with layer A. The strands of the layers C and D extend along an opposite helical lead overlaying the wires of the layer B. The space between the adjacent wires 11 of the smaller cables 16, or even of the large cable 15 may or may not have the material 18 disposed therebetween. Naturally this flexible material 78 will flow unde pressure as the various strands and cables adapt themselves into contact with the others under pressure.

Broadly, the arrangement of wires hereinabove described contemplates an impervious integrated metal sheath which will confine the internal sealing liner or tubes in order to confine the inflating pressure. The ends of the strands of wires and cables will be anchored as heretofore described so as to resist the tremendous Q internal or external'stresses and pressures applied to thepacker.

In event it is desired to arrange a packer ca pable' of withstanding a greater internal and external pressure by providing a sheath capable" of withstanding such greater pressures, additional layers of strands; or strands or a larger diameter or greater strength may be arranged so as'to provide additional composite layers to supplement the layers X and Y.

In order to describe the theory and method of laying the strands as above described to form the-impervious reinforcing sheath, it has beer'i found that the strands should belaid with a helical wrap. This will be generally known as the helical lead and the lead is the actual length of the reinforcing sheath required to make one wrap of strands around the temporary mandrel or support member upon which the sheath is as sembled. This would betaken at the mean di ameter of the layers of reinforcing strands.

Another descriptive term would be "the'angie of lead which would be the angle that the wire would make with a straight line along the Iongitudinal length of the packer on the mean di ameter of the wires.

It has been determined that this angle of lead is animportant factor and has substantial'bear ing upon the characteristics which may be ob=- tained from the packer.

The packers are found to develop a tendency toward-radial expansion due to applied compo= nents of force and such tendency-may be-wziefined in terms of sealing characteristics.

1 The sealing characteristic ofa packer is thus defined as the tendency of the packer to expand or'contract radially when pressure is applied against the initial seal made by inflating the packer against the bore.

A positive sealing characteristic is afurther definition to describe the characteristic obtained when the packer tends to expand radially when pressure is applied against the initial seal.

A negative sealing characteristic is obtained when the packer tends to contract radially when pressureis applied against the initial seal.

There are of course manyvariabi'e: character isticswhich may be fabricatedintothe packer as a function oi the anglejof lead of the strands of the sheath, In general ithas been found thattwo typesof packers embodying different" im portant characteristics can be described asi-llus trative of the range of variable characteristics.

One type of packer isfabricated sothat the internal diameter of the' sheath of the packer must be confin'edatadiameter which approxi mately equalsthesunrof layers of strands which integrate to make upa composite layer; tim'es'; themeandiameter onwhichthe inside layer of strands was fabricated. This is an obvious requirement'in' order toretain an impervious internal sheath and maintain apositive sealing it 1 to nearest composite layer, times the mean di-' ameter on which. the inside Iayer of strands was Iaid at fabrication. This type packer does-net have a positive sealing characteristic at this resultant diameter. Y d The two such, types may be further explained as: V V

first packer meihtaiiise positive sealing characteristic and internal impervious rein forcing sheath. when confined at a diameter which approximately equals the number of layers of strands which integrate to make up a composite raver timesfiie diameter on which the inside layer: of strands was laid at the time of fabricationq L The second typeis where the expansion of the sheathwill' cease when i'inceiifiiied at a iameter which approximately equals the uninfiat'ed jdiemeteror theinside Iay r ofstrands m iitipiied by the number i of layers of strands which integrate to make a composite-layer; thus retaining an inipervious internal reinforcin Sheath having negative Sealing characteristic. H

Of course the maximum sealing efiect' is ob-' tained when the radial component or force: is at its maximum because theii'the radiauy utward force expands the packer to force if against the areas engaged under the greatestpressuie and in this manner Obtain a} maiXit'i'film s dllfig effect.

'It'has been folllldthat 25' tl'l helical Ejliilgle fil creases asthe packer contracts longitudinally upon inflating and the fcrcest'end'ingto expand the packer are reduced, that is, asjthe force inside of the packer due to the i-nfiatir'igfluid automati-' cally resolves itself into. radial-and longitudinal components, the radial component, of force is; reduced as the helical angle increases. If the inflating' action of the packer continues it has been found that the radial and. longitudinal cornponents tend; to balance one another anathewires seemto lock one against" the other, one.

cease radial movement when a diameter is reached where the components are substantially balanced and: there is no further expansion of the pecker beeause of this balancing cf components, irrespective of increasing inflating pressure. V v

The packer'of 9 illustrates an arrangement where the packer hasbe'en expanded to engage a relatively rigid surface such as an impervious formation, or well casing, SO as to prO-' vide' a contact seal between the points and a1 whichis the cylindrical seal at 83.

The expansion of the packer'forins the upper" shoulder. 84 and the lower. shoulder 85 to resist the downward and upward longitudinal loads resp'ectively; Thefluid '81: in the well bore may Y cause such load due to the weight thereof against;

the upper shoulder 84,; or the well pressure may provide the load by. forcing any fluid in the well which flows into the'well' against the lower shoulder85. r

The packer ofjFi g; 101s designed to retainthe the upper external shoulder 81, and-a lower ex--'. .ternal shoulder 88 so as to embraceapart of 75' the exposed shoulders 84 and 85 of the packer as seen in Fig. 9. Thus, the seal with the formationwill be provided not only by the cylindrical sealing surface 83 but by the shoulder surfaces and 81 as well. The packer as seen in Fig. 9, may be of such construction that it is adapted for removal, while the packer as seen in Fig. might be of advantage where the packer is intended to form a part of a permanent or relatively permanent installation, in such a relatively soft formation which could be crushed by the internal pressure applied to the packer.

With this arrangement'it seem apparent that the packer is capable of supporting tremendous loads of liquid in the well bore without damage or injury to the packer and that the shoulders formed in the formation assist in maintaining the seal and retaining the packer against slippage along the bore.

From the foregoing it should be obvious that one 'in possession of some of the characteristics and circumstances which are present in a well bore should be capable of fabricating a packer to cope with the circumstances encountered by designing a packer to obtain the maximum of expansion for location in a relatively soft formation, open hole, or cavity in the well bore. If Y the well formation or the pipe in the Well at the location where the packer is to be set is of known size or diameter and capable of withstanding the pressures of expansion then the packer will be fabricated to obtain the maximum sealing efiect when the packer reaches such known diameter.

Fig. 5 shows the maximum inflation at which the impervious sheath still exists.

n The sealing characteristics defined above change from positive to negative due to the application of an external pressure against the seal of the packer when the'angle of lead approximates to degrees, and the binding or looking is found to occur when the angle of lead is "1. A hydraulically inflatable packer for pro-" viding a seal in wells comprising, end heads, a

skirt extension on each head, a reinforcing fleX-,

ible, annular sheath between said heads and having its ends bearing against the inside of the skirt of each head, an inner, elastic sealing tube confined by said sheath, a cover of elastic material overlying said sheath and said skirt, and

meansto clamp the ends of said sheath inside said skirt so as to retain said sheath against the inflating pressure comprising a radially tapered collar in each end of said sheath.v

2. A hydraulically inflatable packer for providing a seal in wells comprising, end heads, a skirt extension on each head, a reinforcing, flexible, annular sheath having its ends bearing against the insideof the skirt of each head, a cover of elastic material overlying said sheath and said skirt, means to clamp the ends of said sheath-inside said skirt so as to retain said sheath against the inflating hydraulic liquid pressure, and an elastic internal sealing tube inside of said sheath to be expanded and sealed againstthe inside of said head and said means by the inflating liquid.

sheath comprising a plurality of annular layers 3. A hydraulically inflatable packer for provid-. ing a seal in wells comprising, end heads, a skirt extension on each head, a reinforcing, flexible, annular sheath having its ends bearing against the inside of the skirt of each head, a cover of elastic material overlying said sheath and said skirt, means to clamp the ends of said sheath inside said skirt so as to retain said sheath against the inflating hydraulic pressure, and an elastic internal sealing tube inside of said sheath to be flexed and sealed against said sheath the inside of said heads, said clamp means by the inflating liquid, and an adapter layer of flexible material overlying said liner to abut said sheath.

4. A hydraulically inflatable packer comprising, an elastic tube, a retainer head around each end of said tube, an annular skirt extending from each head in the direction of the opposite end of said tube, an annular member around said tube and Spaced inwardly from said skirt and concentric therewith, a sheath anchored at either end between the annular member and the skirt of the head at that end and terminating short of said head to provide a space adjacent said sheath end, an outer sealing casing around said sheath and overlying said heads, and passage means past each annular member to said space and also passage means from said space through each skirt to said outer casing whereby pressurebetween said casing and said tube is equalized.

5. A hollow cylindrical hydraulically inflatable packer comprising, a flexible annular sheath, an elastic. inner sealing tube, an outer elastic casing over said sheath, and means anchored to the ends of said sheath to confine the ends of said tube and to resist the internal and external stresses on said sheath when the packer is inflated, said sheath comprising a plurality of pairs of layers of multi-strand cables with one pair of layers extending helically around said inner tube in one direction and the pair of layers adjacent thereto extending helically around said inner tube in the opposite direction, said layers being concentric with relation to each other when said packer is deflated and the cables of one layer of each pair moving between the cables of the other layer of said pair as said packer is inflated.

6. A hydraulically inflatable packer comprising an elastic inner sealin tube, a flexible, annular sheath thereover of reinforcing strands, a coverof elastic material overlying said sheath, tubular end heads aflixed to the ends of said sheath between said tube and cover so as to anchor the,

sheath against the internal inflating stresses and against the external pressure being packed, said of strands, each layer having the strands thereof in side-by-side position, the layers being concentrio with relation to each other and the strands of two adjacent layers-fitting crest by groove when, the packer is deflated, so that as the packer in? flates the strands of the outer layer move into the widening grooves between the strands of the inner layer in such a manner that when the circumference of the sheath is doubled the-original inner.

' and outer layers are combined into a single comsheath thereover of reinforcing strands, a cover of elastic material overlying said sheath, tubular:

end heads affixed to the ends of said sheath between said tube and cover so as to confine the sheath against the internal inflating liquid prcs sure and against the external pressure being packed, said sheath comprising a plurality of annular layers of strands, each layer having the strands thereof in side-by-side position, the layers being concentric with relation to each other and the strands of adjacent layers fitting crest by groove when the packer is uninflated, so that as the packer inflates the strands of one adjacent layer move into the widening grooves between the strands of the other adjacent layer, in such a manner that when the circumference of the sheath is doubled the two adjacent layers are combined into a single integrated layer made up of alternate strands of said adjacent layers, said adjacent layers extending helically in one direction around said inner tube and said sheath including two additional layers extending helically and in the opposite direction around said first mentioned two adjacent layers so as to provide an outer cross-wrapped composite reinforcing layer means about said adjacent layers.

8. A hydraulically inflatable packer comprising an elastic sealing liner, a plurality of pairs of layers of relatively high tensile strength flexible strands with one pair of layers extending helically around said liner in one direction and the pair of layers adjacent thereto extending helically around said liner in the opposite direction, said layers being concentric with relation to each other when said packer is deflated and the strands of one layer of each pair moving between the strands of the other layer of said pair as said packer is inflated, said strands being of a size and being spaced so as to provide an impervious reinforcing sheath in all positions of the packer from deflated to inflated, and means: to anchor the ends of said strands.

9. A hydraulically inflatable packer comprising, an elastic, sealing liner, a plurality of pairs of layers of strands with one pair of layers extending helically around said liner in one direction and the pair of layers adjacent thereto extending helically around said liner in the opposite direction, said layers being concentric with relation to each other when said packer is deflated and the strands of one layer of each pair moving between the strands of the other layer of said pair as said packer is inflated, said strands being of a size and being spaced so as to provide an impervious reinforcing sheath in all positions of the packer from deflated to inflated, and means to anchor the ends of said strands including a pair of concentric members the inner of which is deformable to clamp the strands against the outer member.

10. A hydraulically inflatable packer comprising, an elastic, sealing liner, a plurality of pairs of layers of flexible metal strands with one pair of layers extending helically around said liner in one direction and the pair of layers adjacent thereto extending helically around said liner in the opposite direction, said layers being concentric with relation to each other when said packer is deflated and the strands of one layer of each pair moving between the strands of the other layer of said pair as said packer is inflated, said strands being of a size and being spaced so as to provide an impervious reinforcing sheath of metal in all positions of the packer from deflated to inflated, and means to anchor the ends of said strands, including inner and outer wedge mem here togrip and retain the ends of said strands.

11. A hydraulically inflatable packer comprising, an elastic tube, a retainer head around each end of said tube, each retainer head including, a body, an annular, inwardly corrugated skirt and spaced inwardly thereof and concentric therewith an annular, outwardly corrugated sleeve, both said skirt and said sleeve extending from said body in the direction of the opposite end of said tube, a flexible, metallic sheath anchored at each end between the said skirt and said sleeve on one of said heads and firmly secured by said corrugations, and an outer sealing elastic casing around said sheath and overlying said skirts. 7

JOHN LYNES.

GEORGE H. ALLEN.

JIMMY D. GARDNER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 873,995 Daugherty Dec. 17, 1907 1,190,790 Moser July 11, 1916 1,772,682 Phipps Aug. 12, 1930 1,826,371 Spindler Oct. 6, 1931 1,838,056 Harpfer Dec. 22, 1931 1,896,492 Macready Feb. 7, 1933 2,128,814 Gish Aug. 30, 1938 2,143,106 Freedlander Jan. 10, 1939 2,151,307 Smith Mar. 21, 1939 2,156,899 Pierce May 2, 1939 2,187,635 Stamps s l. Jan. 16, 1940 2,227,729 Lynes Jan. 7, 1941 2,227,730 Lynes Jan. 7, 1941 2,227,731 Lynes Jan. 7, 1941 2,254,060 Crickmer Aug, 26, 1941 2,300,517 Milton Nov. 3, 1942 2,342,884 Moore Feb. 29, 1944 2,449,514 S'coville Sept. 14, 1948

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