IllllllllllllllllllllllllllIllllllllllllllIllllllllllllllllllllllllllllllll
`U800522454OA
`.
`5,224,540
`[11] Patent Number:
`[19]
`Unlted States Patent
`
`Streich et al.
`[45] Date of Patent:
`Jul. 6, 1993
`
`[75]
`
`[54] DOWNHOLE TOOL APPARATUS WITH
`NON-METALLIC COMPONENTS AND
`METHODS OF DRILLING THEREOF
`Inventors: Steven G. Streich; Donald F.
`Hushbeck; Kevin T. Berscheidt; Rick
`D Jacobi all of Duncan Okla
`'
`'
`’
`’
`[73] Assignee: Halliburton Company, Duncan, Okla.
`[21] Appl- No.: 883,619
`22
`F']
`'
`M 2
`‘ Cd'
`ay 1 t 1992
`
`I
`
`1
`
`4,977,958 12/1940 Miller .................................. 166/205
`
`'
`
`OTHER PUBLICATIONS
`3313:?“ 3:55:22;Eggefigz‘stsafgzgiggfubmhed
`.
`’ pp.
`.
`’
`’
`.
`'
`Halhburton Serv1ces Sales Technical Paper 5—8107
`entitled “Successful Drill Out Of Shoe Joints With
`PDC Bits”, published in Mar., 1939_
`Chapter 4, Fundamentals of DriIIing, by John L.
`Kennedy, PennWell Books, Copyright 1983.
`“Molding Compounds Materials Selection Handbook”,
`ublished b Fiberite Cor oration, Co
`ri ht, 1986.
`y
`p
`py g
`p
`Primary Examiner—Stephen J. Novosad
`Attorne A em or Firm—James R Duzah' Neal R
`y’
`g
`’
`'
`’
`Kennedy
`ABSTRACT
`[57]
`A downhole tool apparatus and methods of drilling the
`apparatus. The apparatus may include, but is not limited
`to, packers and bridge plugs utilizing non-metallic slip
`components. The non-metallic material may include
`engineering grade plastics. In one embodiment, the slips
`d h 1d .
`1
`'
`.
`.
`.
`1
`'
`.
`are separate an
`e
`in pace in an mma posmon
`around the slip wedge by a retainer ring. In another
`embodiment, the slips are integrally formed with a ring
`portion Which holds the slips in the initial position
`.
`.
`.
`.
`.
`.
`you-”‘1 the we'dge’ 1“ ““5 embOd‘me’it’ the ““3 pom.“
`IS made of a fracturable non-metallic material which
`fractures during a setting operation to separate the slips.
`Methods of drilling out the apparatus without signifi-
`cant variations in the drilling speed and weight applied
`to the drill bit may be employed. Alternative drill bit
`-
`-
`tYPCS’ web as p°1y°ry5tanme d‘amond compaCt (PDC)
`b‘“ may 315° be US“
`
`41 Claims. 7 Drawing Sheets
`
`[63]
`
`Related US. Application Data
`,
`,
`,
`Continuation-impartofSer.No.719,740,Jun.21,1991,
`which is a continuation-in-part of Ser. No. 515,019,
`Apr. 26, 1990, abandoned.
`[51] 1m.c1.s ............................................ E213 33/129
`
`[52] US. Cl. ..................
`166/118; 166/123;
`.
`166/123; 166/134; 166/382
`[53] Field or Search --------------- 166/337, 376, 118, 135:
`166/138: 179, 192
`
`6
`[5 ]
`
`R
`
`'
`eferences Cited
`U'S' PATENT DOCUMENTS
`
`6/1936 Armemrout et 31-
`--
`2.043.225
`----- 166/264
`
`5:333:
`3113:?) gag 8: a1. ---------------- 122233
`,
`t
`a
`e a .
`.....
`
`2,589,506
`3/1952 Morrisett
`..... 166/123
`
`9/1962 Allen .......
`3,055,424
`. 166/242 X
`
`......... 166/387
`3,529,667
`9/1970 Malone
`
`3,910,348 10/1975 Pitts ................. 166/134
`
`4.067,358
`1/ 1978 Streich
`137/624.”
`1:382; 1313;? :“ila‘tvayt-"l‘-------- iggjiég
`
`alna 0 e a .
`.
`.....
`,
`,
`
`..... 166/123
`4,708,202 11/1987 Sukup et al.
`
`4,784,226 11/1988 “'yatt .................. 166/376
`
`5/1989 Streich et a1. ........... 166/376
`4,834,184
`...................... 166/153
`4.858.687
`8/1989 \Vatson et a].
`
`
`
`MEGCO EX. 1008
`
`MEGCO Ex. 1008
`
`

`

`US. Patent
`
`July 6, 1993
`
`Sheet 1 of 7
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`5,224,540
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`July 6, 1993
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`US. Patent
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`July 6, 1993
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`US. Patent
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`July 6,1993
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`US. Patent
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`July 6, 1993
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`

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`US. Patent
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`July 6, 1993
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`Sheet 6 of 7
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`5,224,540
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`

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`US. Patent
`
`July 6, 1993
`
`Sheet 7 of 7
`
`5,224,540
`
`”a, 140
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`MEGCO EX. 1008
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`MEGCO Ex. 1008
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`

`

`1
`
`5,224,540
`
`DOWNHOLE TOOL APPARATUS WITH
`NON-METALLIC COMPONENTS AND METHODS
`OF DRILLING THEREOF
`
`This application is a continuation—in-part of co-pend-
`ing application Ser. No. 07/719,740, filed Jun. 21, 1991,
`which was a continuation-in-part of application Ser.
`No. 07/515,019, filed Apr. 26, 1990 and now aban—
`doned.
`
`10
`
`BACKGROUND OF THE INVENTION
`1. Field Of The Invention
`This invention relates to downhole tools for use in
`well bores and methods of drilling such apparatus out of 15
`well bores, and more particularly, to such tools having
`drillable components, such as slips, therein made at least
`partially of non-metallic materials, such as engineering
`grade plastics.
`2. Description Of The Prior Art
`In the drilling or reworking of oil wells, a great vari-
`ety of downhole tools are used. For example, but not by
`way of limitation, it is often desirable to seal tubing or
`other pipe in the casing of the well, such as when it is
`desired to pump cement or other slurry down tubing
`and force the slurry out into a formation. It then be-
`comes necessary to seal the tubing with respect to the
`well casing and to prevent the fluid pressure of the
`slurry from lifting the tubing on of the well. Packers and
`bridge plugs designed for these general purposes are
`well known in the art.
`
`25
`
`30
`
`20
`
`When it is desired to remove many of these downhole
`tools from a well bore, it is frequently simpler and less
`expensive to mill or drill them out rather than to imple-
`ment a complex retrieving Operation. In milling, a mill-
`ing cutter is used to grind the packer or plug, for exam-
`ple, or at least the outer components thereof, out of the
`well bore. Milling is a relatively slow process, but it can
`be used on packers or bridge plugs having relatively
`hard components such as erosion—resistant hard steel.
`One such packer is disclosed in US. Pat. No. 4,151,875
`to Sullaway. assigned to the assignee of the present
`invention and sold under the trademark EZ Disposal
`packer. Other downhole tools in addition to packers
`and bridge plugs may also be drilled out.
`In drilling, a drill bit is used to cut and grind up the
`components of the downhole tool to remove it from the
`well bore. This is a much faster operation than milling,
`but requires the tool to be made out of materials which
`can be accommodated by the drill bit. Typically, soft
`and medium hardness cast iron are used on the pressure
`bearing components, along with some brass and alumi-
`num items. Packers of this type include the Halliburton
`EZ Drill ® and EZ Drill SV ® squeeze packers.
`The EZ Drill SV® squeeze packer, for example,
`includes a lock ring housing, upper slip wedge, lower
`slip wedge, and lower slip support made of soft cast
`iron. These components are mounted on a mandrel
`made of medium hardness cast iron. The EZ Drill®
`squeeze packer is similarly constructed. The Hallibur-
`ton EZ Drill ® bridge plug is also similar, except that it
`does not provide for fluid flow therethrough.
`All of the above-mentioned packers are disclosed in
`Halliburton Services Sales and Service Catalog No. 43,
`pages 2561—2562, and the bridge plug is disclosed in the
`same [catalog on pages 2556—2557.
`The EZ Drill ® packer and bridge plug and the EZ
`Drill SV ® packer are designed for fast removal from
`
`35
`
`4o
`
`45
`
`50
`
`55
`
`65
`
`2
`the well bore by either rotary or cable tool drilling
`methods. Many of the components in these drillable
`packing devices are locked together to prevent their
`spinning while being drilled, and the harder slips are
`grooved so that they will be broken up in small pieces.
`Typically, standard “tri-cone” rotary drill bits are used
`which are rotated at speeds of about 75 to about 120
`rpm. A load of about 5,000 to about 7,000 pounds of
`weight is applied to the bit for initial drilling and in-
`creased as necessary to drill out the remainder of the
`packer or bridge plug, depending upon its size. Drill
`collars may be used as required for weight and bit stabi-
`lization.
`
`Such drillable devices have worked well and provide
`improved operating performance at relatively high tem-
`perature and pressures. The packers and plug men-
`tioned above are designed to withstand pressures of
`about 10,000 psi and temperatures of about 425° F. after
`being set in the well bore. Such pressures and tempera-
`tures require the cast iron components previously dis-
`cussed.
`
`However, drilling out iron components requires cer-
`tain techniques. Ideally, the operator employs varia-
`tions in rotary speed and bit weight to help break up the
`metal parts and reestablish bit penetration should bit
`penetration cease while drilling. A phenomenon known
`as “bit tracking” can occur, wherein the drill bit stays
`on one path and no longer cuts into the downhole tool.
`When this happens, it is necessary to pick up the bit
`above the drilling surface and rapidly recontact the bit
`with the packer or plug and apply weight while con-
`tinuing rotation. This aids in breaking up the established
`bit pattern and helps to reestablish bit penetration. If
`this procedure is used, there are rarely problems. How-
`ever, operators may not apply these techniques or even
`recognize when bit tracking has occurred. The result is
`that drilling times are greatly increased because the bit
`merely wears against the surface of the downhole tool
`rather than cutting into it to break it up.
`While cast iron components may be necessary for the
`high pressures and temperatures for which they are
`designed, it has been determined that many wells expe-
`rience pressures less than 10,000 psi and temperatures
`less than 425° F. This includes most wells cemented. In
`fact, in the majority of wells, the pressure is less than
`about 5,000 psi, and the temperature is less than about
`250° F. Thus, the heavy duty metal construction of the
`previous downhole tools, such as the packers and
`bridge plugs described above, is not necessary for many
`applications, and if cast iron components can be elimi-
`nated or minimized the potential drilling problems re-
`sulting from bit tracking might be avoided as well.
`The downhole tool of the present invention solves
`this problem by providing an apparatus wherein at least
`some of the components, including slips and pressure
`bearing components, are made at least partially of non-
`metallic materials, such as engineering grade plastics.
`Such plastic components are much more easily drilled
`than cast iron, and new drilling methods may be em-
`ployed which use alternative drill bits such as polycrys-
`talline diamond compact bits, or the like, rather than
`standard tri-cone bits.
`
`SUMMARY OF THE INVENTION
`
`The downhole tool apparatus of the present invention
`utilizes non-metallic materials, such as engineering
`grade plastics, to reduce weight, to reduce manufactur-
`ing time and labor, to improve performance through
`
`MEGCO EX. 1008
`
`MEGCO Ex. 1008
`
`

`

`5,224,540
`
`3
`reducing frictional forces of sliding surfaces, to reduce
`costs and to improve drillability of the apparatus when
`drilling is required to remove the apparatus from the
`well bore. Primarily, in this disclosure, the downhole
`tool is characterized by well bore packing apparatus,
`but it is not intended that the invention be limited to
`such packing devices. The non-metallic components in
`the downhole tool apparatus also allow the use of alter-
`native drilling techniques to those previously known.
`In packing apparatus embodiments of the present
`invention, the apparatus may utilize the same general
`geometric configuration of previously known drillable
`packers and bridge plugs while replacing at least some
`of the metal components with non-metallic materials
`which can still withstand the pressures and tempera-
`tures exposed thereto in many well bore applications. In
`other embodiments of the present invention, the appara-
`tus may comprise specific design changes to accommo-
`date the advantages of plastic materials and also to
`allow for the reduced strengths thereof compared to
`metal components.
`.
`In one embodiment of the downhole tool, the inven-
`tion comprises a center mandrel and slip means disposed
`on the mandrel for grippingly engaging the well bore
`when in a set position. In packing embodiments, the
`apparatus further comprises a packing means disposed
`on the mandrel for sealingly engaging the well bore
`when in a set position.
`The slips means comprises a slip wedge positioned
`around the center mandrel, a plurality of slips disposed
`in an initial position around the mandrel and adjacent to
`the wedge, retaining means for holding the slips in the
`initial position, and a slip support on an opposite side of
`the slips from the wedge. In one embodiment, the slips
`are separate and the retaining means is characterized by
`a retaining band extending at least partially around the
`slips. In another embodiment, the retaining means is
`characterized by a ring portion integrally formed with
`the slips. This ring portion is fracturable during a setting
`operation. whereby the slips are separated so that they
`can be moved into gripping engagement with the well
`bore. Hardened inserts may be molded into the slips of
`either embodiment. The inserts may be metallic, such as
`hardened steel, or non-metallic, such as ceramic.
`Any of the mandrel, slips, slip wedges or slip supports
`may be made of the non-metallic material, such as plas-
`tic. Specific plastics include nylon, phenolic materials
`and epoxy resins. The phenolic materials may further
`include any of Fiberite FM40561, Fiberite FM4005 or
`Resinoid 1360. The plastic components may be molded
`or machined.
`One preferred plastic material for at least some of
`these components is a glass reinforced phenolic resin
`having a tensile strength of about 18,000 psi and a com-
`pressive strength of about 40,000 psi, although the in-
`vention is not intended to be limited to this particular
`plastic or a plastic having these specific physical prop-
`erties. The plastic materials are preferably selected such
`that the packing apparatus can withstand well pressures
`less than about 10,000 psi and temperatures less than
`about 425° F. In one preferred embodiment, but not by
`way of limitation, the plastic materials of the packing
`apparatus are selected such that the apparatus can with-
`stand well pressures up to about 5,000 psi and tempera-
`tures up to about 250° F.
`Most of the components of the slip means are sub-
`jected to substantially compressive loading when in a
`sealed operating position in the well bore, although
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
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`
`45
`
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`
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`
`65
`
`4
`some tensile loading may also be experienced. The cen-
`ter mandrel typically ha tensile loading applied thereto
`when setting the packer and when the packer is in its
`operating position.
`One new method of the invention is a well bore pro-
`cess comprising the steps of positioning a downhole tool
`into engagement with the well bore; prior to the step of
`positioning, constructing the tool such that a compo-
`nent thereof is made of a non-metallic material; and then
`drilling the tool out of the well bore. The tool may be
`selected from the group consisting packers and bridge
`plugs, but is not limited to these devices.
`The component made of non-metallic material, may
`be one of several such components. The components
`may be substantially subject to compressive loading.
`Such components in the tool may include lock ring
`housings, slips, slip wedges and slip supports. Some
`components, such as center mandrels of such tools may
`be substantially subjected to tensile loading.
`In another embodiment, the step of drilling is carried
`out using a polycrystalline diamond compact bit. Re-
`gardless of the type of drill bit used, the process may
`further comprise the step of drilling using a drill bit
`without substantially varying the weight applied to the
`drill bit.
`In another method of the invention, a well bore pro-
`cess comprises the steps of positioning and setting a
`packing device in the well bore, a portion of the device
`being made of engineering grade plastic; contacting the
`device with well fluids; and drilling out the device using
`a drill bit having no moving parts such as a polycrystal-
`line diamond compact bit. This or a similar drill bit
`might have been previously used in drilling the well
`bore itself, so the process may be said to further com-
`prise the step of, prior to the step of positioning and
`setting the packer, drilling at least a portion of the well
`bore using a drill bit such as a polycrystalline diamond
`compact bit.
`In one preferred embodiment, the step of contacting
`the packer is at a pressure of less than about 5,000 psi
`and a temperature of less than about 250° F, although
`higher pressures and temperatures may also be encoun-
`tered.
`
`It is an important object of the invention to provide a
`downhole tool apparatus utilizing components, such as
`slip means, made at least partially of non-metallic mate-
`rials and methods of drilling thereof.
`It is another object of the invention to provide a well
`bore packing apparatus using slip means components
`made of engineering grade plastic.
`It is a further object of the invention to provide a
`packing apparatus which may be drilled by alternate
`methods to those using standard rotary drill bits.
`Additional objects and advantages of the invention
`will become apparent as the following detailed descrip-
`tion of the preferred embodiments is read in conjunc-
`tion with the drawings which illustrate such preferred
`embodiments.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 generally illustrates the downhole tool of the
`present invention positioned in a well bore with a drill
`bit disposed thereabove.
`FIG. 2 illustrates a cross section of one embodiment
`of a drillable packer made in accordance with the inven-
`tion.
`FIGS. 3A and 3B show a cross section of a second
`embodiment of a drillable packer.
`
`MEGCO Ex. 1008
`
`MEGCO Ex. 1008
`
`

`

`5,224,540
`
`5
`FIGS. 4A and 4B show a third drillable packer em-
`bodiment.
`FIGS. 5A and 5B illustrate a fourth embodiment of a
`drillable packer.
`FIGS. 6A and 6B show a fifth drillable packer em-
`bodiment with a poppet valve therein.
`FIG. 7 shows a cross section of one embodiment of a
`drillable bridge plug made in accordance with the pres-
`ent invention.
`FIG. 8 illustrates a second embodiment of a drillable
`bridge plug.
`FIG. 9 is a vertical cross section of one preferred
`embodiment of slips used in the drillable packer and
`bridge plug of the plug of the present invention.
`FIG. 10 is an end view of the slips shown in FIG. 9.
`FIG. 11 is an elevational view taken along lines
`11—11 in FIG. 10.
`FIG. 12 shows a vertical cross section of an alternate
`embodiment of slips used in the drillable packer and
`bridge plug of the present invention.
`FIG. 13 is an end view of the slips of FIG. 12.
`FIG. 14 shows an elevation as seen along lines 14—14
`in FIG. 13.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring now to the drawings, and more particu-
`larly to FIG. 1, the downhole tool apparatus of the
`present invention is shown and generally designated by
`the numeral 10. Apparatus 10, which may include, but is
`not limited to, packers, bridge plugs, or similar devices, _
`is shown in an operating position in a well bore 12.
`Apparatus 10 can be set in this position by any manner
`known in the art such as setting on a tubing string or
`wire line. A drill bit 14 connected to the end of a tool or
`tubing string 16 is shown above apparatus 10 in a posi-
`tion to commence the drilling out of apparatus 10 from
`well bore 12. Methods of drilling will be further dis-
`cussed herein.
`
`First Packer Embodiment
`
`Referring now to FIG. 2, the details of a first squeeze
`packer embodiment 20 of apparatus 10 will be de-
`scribed. The size and configuration of packer 20 is sub-
`stantially the same as the previously mentioned prior art
`EZ Drill SV® squeeze packer. Packer 20 defines a
`generally central opening 21 therein.
`Packer 20 comprises a center mandrel 22 on which
`most of the other components are mounted. A lock ring
`housing 24 is disposed around an upper end of mandrel
`22 and generally encloses a lock ring 26.
`Disposed below lock ring housing 24 and pivotally
`connected thereto are a plurality of upper slips 28 ini-
`tially held in place by a retaining means, such as retain-
`ing band or ring 30. A generally conical upper slip
`wedge is disposed around mandrel 22 adjacent to upper
`slips 30. Upper slip wedge 32 is held in place on mandrel
`22 by a wedge retaining ring 34 and a plurality of
`screws 36.
`
`Adjacent to the lower end of upper slip wedge 32 is
`an upper back-up ring 37 and an upper packer shoe 38
`connected to the upper slip wedge by a pin 39. Below
`upper packer shoe 38 are a pair of end packer elements
`40 separated by center packer element 42. A lower
`packer shoe 44 and lower back-up ring 45 are disposed
`adjacent to the lowermost end packer element 40.
`A generally conical lower slip wedge 46 is positioned
`around mandrel 22 adjacent to lower packer shoe 44,
`
`6
`and a pin 48 connects the lower packer shoe to the
`lower slip wedge.
`'
`Lower slip wedge 46 is initially attached to mandrel
`22 by a plurality of screws 50 and a wedge retaining
`ring 52 in a manner similar to that for upper slip wedge
`32. A plurality of lower slips 54 are disposed adjacent to
`lower slip wedge 46 and are initially held in place by a
`retaining means, such as retaining band or ring 56.
`Lower slips 54 are pivotally connected to the upper end
`of a lower slip support 58. Mandre] 22 is attached to
`lower slip support 58 at threaded connection 60.
`Disposed in mandrel 22 at the upper end thereof is a
`tension sleeve 62 below which is an internal seal 64.
`Tension sleeve 62 is adapted for connection with a
`setting tool (not shown) of a kind known in the art.
`A collet-latch sliding valve66 is slidably disposed in
`central opening 21 at the lower end of mandrel 22 adja-
`cent to fluid ports 68 in the mandrel. Fluid ports 68 in
`mandrel 22 are in communication with fluid ports 70 in
`lower slip housing 58. The lower end of lower slip
`support 58 is closed below ports 70.
`Sliding valve 66 defines a plurality of valve ports 72
`which can be aligned with fluid ports 68 in mandrel 22
`when sliding valve 66 is in an open position. Thus, fluid
`can flow through central opening 21.
`On the upper end of sliding valve 66 are a plurality of
`collet fingers 67 which are adapted for latching and
`unlatching with a valve actuation tool (not shown) of a
`kind known in the art. This actuation tool is used to
`open and close sliding valve 66 as further discussed
`herein. As illustrated in FIG. 2, sliding valve 66 is in a
`closed position wherein fluid ports 68 are sealed by
`upper and lower valve seals 74 and 76.
`In prior art drillable packers and bridge plugs of this
`type, mandrel 22 is made of a medium hardness cast
`iron, and lock ring housing 24, upper slip Wedge 32,
`lower slip wedge 46 and lower slip support 58 are made
`of soft cast iron for drillability. Most of the other com-
`ponents are made of aluminum, brass or rubber which,
`of course, are relatively easy to drill. Prior art upper
`and lower slips 28 and 54 are made of hard cast iron, but
`are grooved so that they will easily be broken up in
`small pieces when contacted by the drill bit during a
`drilling operation.
`As previously described, the soft cast iron construc-
`tion of prior art lock ring housings, upper and lower slip
`wedges, and lower slip supports are adapted for rela-
`tively high pressure and temperature conditions, while
`a majority of well applications do not require a design
`for such conditions. Thus, the apparatus of the present
`invention, which is generally designed for pressures
`lower than 10,000 psi and temperatures lower than 425°
`F., utilizes engineering grade plastics for at least some
`of the components. For example, the apparatus may be
`designed for pressures up to about 5,000 psi and temper-
`atures up to about,250° F., although the invention is not
`intended to be limited to these particular conditions.
`In first packer embodiment 20, at least some of the
`previously soft cast iron components of the slip means,
`such as lock ring housing 24, upper and lower slip
`wedges 32 and 46 and lower slip support 58 are made of
`engineering grade plastics. In particular, upper and
`lower slip wedges 32 and 46 are subjected to substan-
`tially compressive loading. Since engineering grade
`plastics exhibit good strength in compression,
`they
`make excellent choices for use in components subjected
`to compressive loading. Lower slip support 58 is also
`subjected to substantially compressive loading and can
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`MEGCO EX. 1008
`
`MEGCO Ex. 1008
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`

`5,224,540
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`7
`be made of engineering grade plastic when packer 20 is
`subjected to relative low pressures and temperatures.
`Lock ring housing 24 is mostly in compression, but
`does exhibit some tensile loading. However,
`in most
`situations, this tensile loading is minimal, and lock ring
`housing 24 may also be made of an engineering grade
`plastic of substantially the same type as upper and lower
`slip wedges 32 and 46 and also lower slip housing 58.
`Upper and lower slips 28 and 54 are illustrated in
`FIG. 2 as having a conventional configuration. How-
`ever, non-metallic materials may be used, and thus
`upper and lower slips 28 and 54 may be made of plastic,
`for example, in some applications. Hardened inserts for
`gripping well bore 12 when packer 20 is set may be
`required as part of the plastic slips. New embodiments
`of slips utilizing such non-metallic materials will be
`described later herein.
`Lock ring housing 24, upper slip wedge 32, lower slip
`wedge 46, and lower slip housing 58 comprise approxi-
`mately 75% of the cast iron of the prior art squeeze
`packers. Thus, replacing these components with similar
`components made of engineering grade plastics will
`enhance the drillability of packer 20 and reduce the time
`and cost required therefor.
`Mandrel 22 is subjected to tensile loading during
`setting and operation, and many plastics will not be
`acceptable materials therefor. However, some engineer-
`ing plastics exhibit good tensile loading characteristics,
`so that construction of mandrel 22 from such plastics is
`possible. Reinforcements may be provided in the plastic
`resin as necessary.
`
`Example
`
`A first embodiment packer 20 was constructed in
`which upper slip wedge 32 and lower slip wedge 46
`were constructed by molding the parts to size from a
`phenolic resin plastic with glass reinforcement. The
`specific material used was Fiberite 4056J manufactured
`by Fiberite Corporation of Winona, Minn. This material
`is classified by the manufacturer as a two stage phenolic
`with glass reinforcement. It has a tensile strength of
`18.000 psi and a compressive strength of 40.000 psi.
`The test packer 20 held to 8,500 psi without failure to
`wedges 32 and 46, more than sufficient for most well
`bore conditions.
`
`Second Packer Embodiment
`
`Referring now to FIGS. 3A and 3B, the details of a
`second squeeze packer embodiment 100 of packing
`apparatus 10 are shown. While first embodiment 20
`incorporates the same configuration and general com-
`ponents as prior art packers made of metal, second
`packer embodiment 100 and the other embodiments
`described herein comprise specific design features to
`accommodate the benefits and problems of using non-
`metallic components, such as plastic.
`Packer 100 comprises a center mandrel 102 on which
`most of the other components are mounted. Mandrel
`102 may be described as a thick cross-sectional mandrel
`having a relatively thicker wall thickness than typical
`packer mandrels, including center mandrel 22 of first
`embodiment 20. A thick cross-sectional mandrel may be
`generally defined as one in which the central opening
`therethrough has a diameter less than about half of the
`outside diameter of the mandrel. That is, mandrel cen-
`tral opening 104 in central mandrel 102 has a diameter
`less than about half the outside of center mandrel 102. It
`is contemplated that a thick cross-sectional mandrel will
`
`8
`be required if it is constructed from a material having
`relatively low physical properties. In particular, such
`materials may include phenolics and similar plastic ma-
`terials.
`
`An upper support 106 is attached to the upper end of
`center mandrel 102 at threaded connection 108. In an
`alternate embodiment, center mandrel 102 and upper
`support 106 are integrally formed and there is no
`threaded connection 108. A spacer ring or upper slip
`support 110 is disposed on the outside of mandrel 102
`just below upper support 106. Spacer ring 110 is initially
`attached to center mandrel 102 by at least one shear pin
`112. A downwardly and inwardly tapered shoulder 114
`is defined on the lower side of spacer ring 110.
`Disposed below spacer ring 110 is an upper slip
`means 115 comprisingslips and a wedge. Referring now
`to FIGS. 9—11, a new embodiment of upper slip means
`115 is characterized as comprising a plurality of sepa-
`rate non-metallic upper slips 116 held in place by a
`retaining means, such as retaining band or ring 117
`extending at least partially around slips 116. Upper slips
`116 may be held in place by other types of retaining
`means as well, such as pins. Slips 116 are preferably
`circumferentially spaced such that a longitudinally ex-
`tending gap 119 is defined therebetween.
`.
`Each slip 116 has a downwardly and inwardly slop-
`ing shoulder 118 forming the upper end thereof. The
`taper of each shoulder 118 conforms to the taper of
`shoulder 114 on spacer ring 110, and slips 116 are
`adapted for sliding engagement with shoulder 114, as
`will be further described herein.
`An upwardly and inwardly facing taper 120 is de-
`fined in the lower end of each slip 116. Each taper 120
`generally faces the outside of center mandrel 102.
`Referring now to FIGS. 12—14, an alternate embodi-
`ment of the slips of upper slip means 115 is shown. In
`this embodiment, a plurality of upper slips 116, are inte-
`grally formed at the upper ends thereof such that a ring
`portion 121 is formed. Ring portion 121 may be consid-
`ered a retaining means for holding upper slips 116' in
`their initial position around center mandrel 102. The
`lower ends of slips 116’ extend from ring portion 121
`and are circumferentially separated by a plurality of
`longitudinally extending gaps 123. That is, in the second
`embodiment upper slip means 115 is a characterized as
`comprising a single piece molded or otherwise formed
`from a non-metallic material, such as plastic.
`Each slip 116’, like each slip 116, has downwardly
`and inwardly sloping shoulder 118 forming the upper
`end thereof and generally defined in ring portion 121.
`Again, the taper of each shoulder 118 conforms to the
`taper of shoulder 114 on spacer ring 110, and slips 116'
`are adapted for sliding engagement with shoulder 114,
`as will be further described herein.
`As with slips 116, an upwardly and inwardly facing
`taper 120 is defined in the lower end of each slip 116’.
`As before, each taper 120 generally faces the outside of
`center mandrel 102.
`
`A plurality of inserts or teeth