Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 1 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 1 of 19
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`EXHIBIT A
`EXHIBIT A
`6:22-cv-1316
`6:22-cv-1316
`
`

`

`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 2 of 19
`eeNTT TAA
`
`US010465445B2
`
`a2) United States Patent
`US 10,465,445 B2
`(10) Patent No.:
`
`(45) Date of Patent: Nov. 5, 2019
`Getzlafet al.
`
`(54)
`
`(71)
`
`(72)
`
`CASING FLOAT TOOL
`
`Applicant: NCS Multistage Inc., Calgary, Alberta
`(CA)
`
`Inventors: Donald Getzlaf, Calgary (CA); Marty
`Stromquist, Calgary (CA); John
`Ravensbergen, DeWinton (CA); David
`Devlin, Calgary (CA); Douglas
`Braden, Calgary (CA); Travis Harris,
`Houston, TX (US)
`
`(73)
`
`Assignee: NCS MULTISTAGE INC., Calgary,
`Alberta (CA)
`
`(*)
`
`Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21)
`
`Appl. No.: 15/919,370
`
`(22)
`
`Filed:
`
`Mar.13, 2018
`
`(65)
`
`(60)
`
`Prior Publication Data
`
`US 2018/0202260 Al
`
`Jul. 19, 2018
`
`Related U.S. Application Data
`
`Continuation of application No. 15/421,222, filed on
`Jan. 31, 2017, which is a division of application No.
`(Continued)
`
`(51)
`
`Int. Cl.
`
`E21B 7/20
`E21B 33/14
`
`(52)
`
`USS. Cl.
`
`(2006.01)
`(2006.01)
`(Continued)
`
`CPC wees E21B 7/20 (2013.01); E21B 17/08
`(2013.01); E21B 17/14 (2013.01); E21B 21/10
`(2013.01);
`
`(58) Field of Classification Search
`CPC wee E21B 7/20; E21B 17/14; E21B 33/146
`See application file for complete search history.
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2,008,818 A
`2,117,318 A
`
`7/1935 Corbett
`5/1938 Hanes
`(Continued)
`
`OTHER PUBLICATIONS
`
`Rogers, H. E., Bolado, D. L., & Sullaway, B. L. (Jan. 1, 1998).
`Buoyancy Assist Extends Casing Reach in Horizontal Wells. Soci-
`ety of Petroleum Engineers. (Year: 1998).*
`
`Primary Examiner — Kristyn A Hall
`Assistant Examiner — Tara E Schimpf
`
`(57)
`
`ABSTRACT
`
`A rupture disc assembly and a float tool incorporating the
`rupture disc assembly is disclosed. The rupture disc assem-
`bly may include a rupture disc assembly comprising a
`rupture disc, an upper tubular portion and a lower tubular
`portion, and a securing mechanism for holding the rupture
`disc between the upper and lowertubular portions. A float
`tool for creating a buoyant chamber in a casing string may
`include the rupture disc assembly and a sealing device for
`sealing the lower end of the casing string, the buoyant,
`sealed chamber may becreated there between. In operation,
`applied fluid pressure causes the rupture disc to move
`downward. The rupture disc may be shattered by contact
`with a surface on the lower tubular portion. Full casing
`internal diameter may be restored in the region where the
`rupture disc formerly sealed the casing.
`
`(Continued)
`
`57 Claims, 7 Drawing Sheets
`
`
` :
`tht SSE<
`
`KO
`
`-58
`
`247227 24°60 *28
`
`$39
`
`~26
`
`t56
`
`“14
`
`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 3 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 3 of 19
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`US 10,465,445 B2
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`Page 2
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`*A
`
`A AAA
`
`*®
`
`Related U.S. Application Data
`
`(56)
`
`13/930,683, filed on Jun. 28, 2013, now Pat. No.
`9,593,542.
`
`(60)
`
`Provisional application No. 61/761,070, filed on Feb.
`5, 2013.
`
`3,779,263
`3,831,680
`
`5,479,986
`5,829,526
`5,924,696
`
`12/1973
`8/1974
`
`1/1996
`11/1998
`7/1999
`
`8/2006
`1/2010
`2/2010
`7/2010
`4/2013
`5/2008
`
`Edwards
`Edwards 0... cee E21B 21/10
`166/311
`
`Gano
`Rogers
`Frazier oo. E21B 34/063
`138/90
`
`Williams
`Vert et al.
`Ammal
`Vert et al.
`Schultz et al.
`Keller wees E21B 34/06
`166/380
`ELvin vice eceeceeeeenees E21B 7/061
`166/382
`
`(51)
`
`Int. Cl.
`
`E21B 21/10
`E21B 17/14
`E21B 34/06
`E21B 17/08
`
`(52)
`
`US. Cl.
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`
`7,090,027
`7,640,984
`7,661,480
`7,757,764
`8,424,605
`2008/0115942
`
`Bl
`B2
`B2
`B2
`Bl
`Al*
`
`2011/0253387
`
`Al*
`
`10/2011
`
`CPC wee £21B 33/14 (2013.01); E21B 33/146
`(2013.01); E21B 34/063 (2013.01)
`
`* cited by examiner
`
`

`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 4 of 19
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`U.S. Patent
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`Nov. 5, 2019
`
`Sheet 1 of 7
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`US 10,465,445 B2
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`
`
`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 5 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page5of 19
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`U.S. Patent
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`Nov. 5, 2019
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`Sheet 2 of 7
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`US 10,465,445 B2
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`16
`
`20
`
`(24729 505527,-44_-18
`
`24s
`
`22~
`
`FIG.2
`
`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 6 of 19
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`U.S. Patent
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`Nov. 5, 2019
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`Sheet 3 of 7
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`US 10,465,445 B2
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`
`
`FIG.3
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`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 7 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 7 of 19
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`U.S. Patent
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`Nov. 5, 2019
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`Sheet 4 of 7
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`US 10,465,445 B2
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`FIG.4C
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`
`
`FIG.4A
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`FIG.4B
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`40
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`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page8of 19
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`U.S. Patent
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`Nov. 5, 2019
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`Sheet 5 of 7
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`US 10,465,445 B2
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`FIG.5
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`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 9 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 9 of 19
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`U.S. Patent
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`Nov. 5, 2019
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`Sheet 6 of 7
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`US 10,465,445 B2
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`

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`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 10 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 10 of 19
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`U.S. Patent
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`Nov. 5, 2019
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`Sheet 7 of 7
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`US 10,465,445 B2
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`FIG.7
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`

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`US 10,465,445 B2
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`2
`BRIEF SUMMARY
`
`1
`CASING FLOAT TOOL
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`This application is a continuation of U.S. application Ser.
`No. 15/421,222 filed on Jan. 31, 2017, which is a division of
`USS. application Ser. No. 13/930,683 filed on Jun. 28, 2013,
`now issued as U.S. Pat. No. 9,593,542 which claims the
`benefit of U.S. Provisional Application No. 61/761,070 filed
`on Feb. 5, 2013,
`the disclosures of which are hereby
`incorporated by reference in their entireties.
`
`FIELD OF THE INVENTION
`
`This invention relates to a method and apparatus for
`sealing well casings.
`
`BACKGROUND
`
`In manywells, it may be difficult to run the casing to great
`depths becausefriction between the wellbore and the casing
`often results in a substantial amount of drag. This is par-
`ticularly true in horizontal and/or deviated wells. In some
`cases, the drag on the casing can exceedthe available weight
`in the vertical section of the wellbore. If there is insufficient
`
`it may be
`weight in the vertical portion of the wellbore,
`difficult or impossible to overcome drag in the wellbore.
`Various attempts have been made to overcome this drag
`and achieve greater well depths and/or to achieve a hori-
`zontal well. For example, techniquesto alter wellbore geom-
`etry are available, but these techniques can be time-consum-
`ing and expensive. Techniques to lighten or “float” the
`casing have been used to extend the depth of well. For
`example, there exists techniques in which the ends of a
`casing string portion are plugged, the plugged portion is
`filled with a low density, miscible fluid to provide a buoyant
`force. After the pluggedportionis placed in the wellbore, the
`plugs mustbe drilled out, and the low density miscible fluid
`is forced out into the wellbore. The extra step of drilling out
`increases completion time. Someflotation devices require a
`packer to seal the casing above the air chamber. In these
`cases, the chamberis sealed at its upper end by a packer. The
`packer may be removed from the casing string using a
`conventional drill-type workstring, for example.
`In manycasing float techniques and devices, it may not be
`possible to achieve full casing ID (Gnside diameter) follow-
`ing the opening ofthe air chamber.It is desirable to achieve
`full casing ID so that downhole tools can be conveyedto this
`region of the casing string and so that operations, such as
`cementing can be easily carried out using conventional
`ball-drop techniques, or other conventional
`techniques.
`Also, many float devices require the use of specialized float
`shoes and/or float collars.
`Tt would be desirable to have a flotation chamber (also
`referred to herein as a “float chamber” or “buoyant cham-
`ber”) which is easy and relatively inexpensive to install on
`a casing string and which can be used with conventional
`float equipment such as float shoes and float collars, and
`with conventional equipment such as landing collars and
`cementing plugs. Further, it would be desirable if the parts
`of the float chamber could be easily removed from the
`wellbore and/or that the removal could result in full casing
`ID so that various downhole operations could be readily
`performed following removal or opening of the buoyant
`chamber.
`
`10
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`20
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`25
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`Generally, this disclosure relates to an improved rupture
`disc assembly and improved rupture disc within the assem-
`bly wherein the rupture disc, when installed in the wellbore,
`can be ruptured by engagement with an impact surface of a
`tubular once a rupturing force is applied to the disc, such as
`by hydraulic fluid under pressure. The disc can be impelled
`to impact against this impact surface, and ruptureas a result.
`For example, the disc may be engaged within the casing
`string by a securing mechanism, which maybea shear ring.
`Whenfreed from the constraints of the securing mechanism,
`the disc shatters against an impact surface within the casing
`string (e.g. a surface of a tubular). Hydraulic pressure does
`not cause rupture ofthe disc all by itself. Rather, hydraulic
`pressure causes disruption or shearing of the securing
`mechanism, such that
`the rupture disc is shattered by
`engagement against an impact surface within the casing
`string. The hydraulic pressure required to cause disruption of
`the securing mechanism is less than the hydraulic pressure
`that would normally be required to break the rupture disc.
`The engagementof the disc against the impact surface (the
`disc being impelled against the impact surface) allows the
`disc to rupture at lower pressure than would generally be
`required if hydraulic pressure alone was the sole mechanism
`for rupturing the disc, thereby allowing less hydraulic pres-
`sure to be required for the disc to be ruptured. Also, as will
`be described below, this allows the disc to be broken into
`suitably-sized pieces that will not affect wellbore equipment
`such as float devices.
`
`There is no need to send weights, sharp objects or other
`devices(e.g. drop bars or sinker bars) downthe casing string
`to break the rupture disc. Nor is there a need for complicated
`tubular arrangements, such as sliding sleeves to break the
`rupture disc. Such sleeves do not tend to break the disc into
`sufficiently small pieces. In the present arrangement, the
`rupture disc and rupture disc assembly can be so arranged
`that the rupture disc gets broken in sufliciently small pieces
`that the disc pieces can be removed by fiuid circulation,
`without damaging the casing string. In addition, full casing
`ID (inside diameter) is restored after the rupture disc is
`broken, so that there is no need to drill out any part of the
`device. This full casing ID is useful for use in ball-drop
`systems. Once the disc has ruptured, normal operations,
`such as cementing, may be performed. The device is
`straight-forward to install, avoids the cost and complexity of
`many known casing flotation methods and devices, and
`decreases completion time.
`According to one aspect, the rupture disc assembly com-
`prises an upper tubular member, and a lower tubular member
`coupled with the upper tubular member. The rupture disc is
`held in sealing engagement between the upper tubular
`memberandthe lower tubular memberby a securing mecha-
`nism. The rupture disc is secured above or within the lower
`tubular member such that the rupture disc can move down-
`ward into a constricted area of the lower tubular member in
`
`response to hydraulic fluid pressure, and rupture as a result
`of the impact against the lower tubular member.
`In one embodiment, the securing mechanism generally
`provides a convenient meansto fluidically seal the rupture
`disc within the casing string, and essentially, to facilitate
`rupturing of the disc, by the mechanisms described herein.
`In one example, the securing mechanism is a shearring, the
`shear ring having a continuous side surface and a circum-
`ferential aperture. The lower circumferential edge of the
`shear ring includes a plurality of tabs inwardly extending
`into the aperture. Generally, the threshold shearing pressure
`
`

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`3
`ofthe tabs is less than the rupture burst pressure of the disc
`(e.g. the pressure at which hydraulic pressure alone causes
`rupture of the disc), so that the tabs are sheared before the
`disc is shattered. The shearing allows sudden or rapid free
`movement of the disc in the direction of the lower tubular
`
`4
`tubing either closer or farther from the wellhead and that
`various embodiments of the present invention may be uti-
`lized in various orientations, such as inclined, deviated,
`horizontal, vertical, etc.
`Float Tool
`
`member, so that the disc can be shattered by impact.
`It is desirable for the rupture disc to be shattered into
`sufficiently small pieces that the shattered pieces do not
`damage the casing string, and so that the pieces do not clog
`equipment(such as the float shoe) within the casing string.
`To accomplish this, various configurations of the rupture
`disc may be employed. For example, the rupture disc may
`have a pattern of grooves etched on the outer surface of the
`dome, the grooves providing lines of weakness to facilitate
`breakageof the disc into suitably-sized pieces. The thickness
`of the rupture disc may also be such as to improve the
`breakability characteristics. The small size of the pieces
`allow the rupture disc assembly to be used with ball-drop
`systems (typically, the smallest ball drop is less than one
`inch).
`According to one embodiment, the float tool may further
`comprise a debris catcher disposed on the casing string
`downhole of the disc to catch the disc pieces after the disc
`has been broken.
`
`10
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`30
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`Referring to the drawings, FIG. 1 shows an embodiment
`of a float tool, generally designated by the numeral 90, after
`the float tool has been run into wellbore 92. Float tool 90 is
`installed within casing string 94. An annulus 110 may be
`defined between the casing and the wellbore 92.
`According to this embodiment, float tool 90 includes a
`rupture disc assembly 10. In the illustrated embodiment,
`rupture disc assembly 10 is installed in the vertical portion
`130 of wellbore 92, proximal to the bend 150 leading to the
`horizontal portion 140 of the wellbore. Variations in the
`placement of the rupture disc assembly are possible. Gen-
`erally, the rupture disc assembly should be installed such to
`maximize vertical weight on the casing string, while mini-
`mizing horizontal weight. Rupture disc assembly 10 forms
`a temporary isolation barrier, isolating a fluid-filled, upper
`section ofthe string 93 from a sealed, buoyant chamber 120
`formed in the string between the rupture disc assembly 10
`and a sealing device, such as a float shoe 96 disposed at the
`lower end ofthe casing string.
`Float shoe 96 forms the lower boundary of buoyant
`Various embodiments include an improved float tool for
`chamber 120. As will be appreciated, an alternative float
`creating a buoyant chamber in a casing string, wherein the
`device, such asafloat collar, may be used as a substitute for
`float tool comprises the above-described rupture disc assem-
`float shoe 96, or may be used in addition to float shoe 96.
`bly; a methodthat utilizes the present rupture disc assembly
`Float shoes, float collars and similar devices are herein
`to first seal, and then unseal, a well casing; a method that
`referred to as “float devices”. In the illustrated embodiment,
`utilizes the present rupture disc assembly as part of the
`both a float shoe 96 and float collar 98 are included. Float
`installation of a casing; a method that utilizes the present
`rupture disc assembly as part of the running in of a casing
`string into a wellbore.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`
`VIEWS OF THE DRAWING(S)
`
`FIG.1 is a cross-sectional view of a float tool according
`to one embodiment installed within a casing string in a
`wellbore having both vertical and horizontal portions.
`FIG.2 is a cross-sectional view of a rupture disc assembly
`according to an embodimentthat is adapted for installation
`in a casing string.
`FIG. 3 is schematic, perspective view of a rupture disc
`assembly according to one embodiment.
`FIG. 4A is an end view of a shear ring according to one
`embodiment.
`
`FIG.4Bis a sectional view of a rupture disc holder with
`a shear ring taken through line A-A in FIG. 4A.
`FIG. 4C is an enlarged view of a portion of two tabs on
`the shear ring shown in FIG. 4A.
`FIG.5 is a perspective view of the rupture disc according
`to one embodiment, showing the surface etched in a grid-
`like pattern.
`FIG. 6 is a schematic drawing of an etched rupture disc
`within a shear ring.
`FIG.7 is a perspective view of a debris catcher according
`to one embodimentthat is adapted forinstallation in a casing
`string.
`
`DETAILED DESCRIPTION
`
`In the following description, directional terms such as
`“above”, “below”, “upper”, “lower”, “uphole”, “downhole”,
`etc. are used for convenience in referring to the accompa-
`nying drawings. One of skill in the art will recognize that
`such directional language refers to locations in downhole
`
`35
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`collar 98 may be positioned uphole of the float shoe 96.
`When present, the float collar serves as a redundant fluid
`inflow prevention means. The float collar is similar in
`construction to the float shoe, including a valve (not shown)
`that prevents wellbore fluid from entering the buoyant
`chamber. Similarly, the float shoe generally includes a check
`valve (not shown) that prevents inflow of fluid from the
`wellbore during running in or lowering the casing string into
`the wellbore.
`
`Float shoes are generally knownin the art. For example,
`USS. Pat. Nos. 2,117,318 and 2,008,818 describe float shoes.
`Float shoes may be closed by assistance with a spring. Once
`closed, pressure outside the float shoe may keep the shoe
`closed. In some float shoes, its check valve can be opened
`when fluid flow through the casing string is desired, for
`example, when cementing operations are to begin. In some
`cases,
`the float shoe may be drilled out after run-in is
`complete. Whenpresent, the float collar often has a landing
`surface for a wiper displacementplug. In addition to a float
`shoe and/orfloat collar, a baffle collar and/or guide shoe may
`be present. The present float tool 90, and the rupture disc
`assembly 10 therein, may be adapted to be compatible with
`mostfloat shoes, landing collars and float collars.
`Buoyant chamber 120 in float tool 90 may be created as
`a result of sealing of the lower end of casing string 94 with
`float shoe 96 and sealing of an upper end ofcasing string 94
`with rupture disc assembly 10. Rupture disc assembly 10
`includes a rupture disc 30 that will be ruptured at a subse-
`quentpoint in time, as will be discussed below. Rupture disc
`30 is generally a hemispherical dome, having a convex
`surface 36 oriented in the up-hole direction, and having a
`burst or rupture pressure (e.g. the pressure at which hydrau-
`lic pressure alone can break the disc) greater than the
`hydraulic pressure in the casing string when the casing string
`is being run, so as to avoid premature breakage of the disc.
`The distance between float shoe 96 and rupture disc assem-
`
`

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`5
`installed. The landing collar is then installed on the casing
`bly 10 is selected to control the force tending to run the
`string. Drilling mud may be added to ensure that the float
`casing into the hole, and to maximize the vertical weight of
`shoe 96 is functioning properly. No fluid is added to the
`the casing string, as noted above.
`casing prior to installing the rupture disc assembly (unless
`Optionally, a debris catcher 70 maybe installed downhole
`that a liquid or a gas other than air is to be used). Once a
`of rupture disc assembly 10, generally in the horizontal
`desired amount of casing is run into the wellbore, rupture
`portion 140 of the wellbore 92. The debris catcher may be
`any suitable means for capturing pieces of the rupture disc,
`disc assembly 10 is installed. The remaining casing is run in,
`
`once shattered. For example,afilter, a baffle, a screen, etc. filling the casing with mud.
`may be usedas the debris catcher. In theillustrated embodi-
`The casing string,
`including float tool 90,
`is run into
`ment, a particular type of debris catcher 70 is shown, with
`wellbore 91 until the friction drag on the casing string 94
`projections on debris catcher 70 facing uphole so as to
`with the walls of wellbore 92 will not allow the casing string
`capture debris from rupture disc 30. The debris catcher can
`to be run to a greater depth. When run to the desired or
`be installed into the casing string by threaded connection,
`maximum depth, float shoe 96 may be located close to the
`between a landing collar 100 and a pup joint (not shown),
`“toe” or bottom of the wellbore 92. Rupture disc assembly
`whenpresent. Furtherillustrative details of debris catcher 70
`10 maybepositionedin the vertical section 130 of the well.
`are presented hereinbelow.
`The vertical weight of the casing string assists in overcom-
`Moreparticularly, landing collar 100 may be positioned
`ing drag on the casing string, allowing the casing string to
`between sealing device 96 and rupture disc assembly 10.
`be positioned to a greater depth, and/or to be movedhori-
`The landing collar may be present on the surface ofthe float
`zontally in the wellbore. The hydrostatic pressure during
`collar, when present. Landing collar 100 may be generally
`run-in mustbe less than the rupture burst pressure of rupture
`used in cementing operations for receiving cementing plugs,
`disc 30, to prevent premature rupture of the disc. Generally,
`such as a wiper plug. Suitable landing collars are known in
`the rupture disc may have a pressure rating of 10,000 to
`the art, and float tool 100 does not require that a particular
`30,000 psi, for example.
`landing collar be used, so long as the landing collar has
`Once the casing has run and landed, circulating equip-
`surface for receiving a plug and so long as the landing collar
`ment may beinstalled. The rupture disc is then burst by
`can be suitably installed on the casing string.
`pressuring the casing from surface. To accomplishthis, fluid
`The region of the casing string between rupture disc
`pressure (e.g., from the surface) is applied through the
`assembly 10 and float shoe 96 has increased buoyancy. The
`casing string 94. Thefluid exerts force on the convex side 36
`casing in this region may beair-filled. Whenthis is the case,
`of rupture disc 30, and on a securing mechanism holding the
`there is no need to fill the casing string with fluid prior to
`rupture disc in place, as discussed in further detail herein-
`running the casing string in, and there is no need to substitute
`below. The force is sufficient to overcome the engagement
`the air in the casing once installed in the well. However,
`function of the securing mechanism, causing the disc to
`fluids of lesser density than the fluid in the upper casing
`suddenly move downward, and shatter against a region of
`string 93 may be used. For example, the buoyant chamber
`the casing string (such as an impact surface on a tubular), as
`maybefilled with a gas such as nitrogen, carbon dioxide or
`will be described in more detail below. Once the rupture disc
`air, and other gases mayalso be suitable. Light liquids may
`has burst, fluid pumping is continued for a short time, and
`also be used. Generally, the buoyant chamber mustbefilled
`then stopped. The rupture of the disc should be evident from
`with fluid that has a lower specific gravity than the well fluid
`the surface by observing both movement and sound. There
`in the wellbore in whichit is run, and generally, the choice
`mayalso be a pressure drop.
`of which gas or liquid to use, is dependent on factors such
`After the steps involvedin installing the float tool into the
`as the well conditions and the amount of buoyancy desired.
`wellbore have been performed, and the disc has been shat-
`In ordertofill the casing string with the lighter fluid or gas,
`tered, additional operations can be performed. Fluid flow
`the casing string may be sealed with the float device, the
`through the casing string following rupture mayallow the air
`landing collar installed, and the casing ran into the wellbore
`or other fluid or gas that was in the buoyant chamberto rise
`with air. The air may then be flushed out,andthestring filled
`to the surface and be vented from the casing string, for
`with the gas or liquid from surface, prior to installing the
`example. The cavity can then befilled with other fluid (e.g.
`rupture burst assembly. The buoyancy of the buoyant cham-
`non-flotation fluid). For example, the casing string may be
`ber assists in running the casing string to the desired depth.
`filled with drilling fluid. When float shoe 96 is opened,
`Method of Installing Casing String
`conventional cementing operations can begin.
`It
`is also
`Thefloat tool, and thus rupture disc assembly 10, may be
`possible to use the float tool of the present disclosure in
`used in a method of installing a casing string, and in a
`reverse cementing operations.
`In reverse cementing, a
`method to float a casing. As noted above, running a casing
`cementslurry may be pumped downthe annulus 110, rather
`string in deviated wells and in long horizontal wells can
`than through the casing. When cementing operations are
`result in significantly increased drag forces. A casing string
`performed, a cement plug is delivered through the casing
`may becomestuck before reaching the desired location. This
`string. The cement plug mayassist in sweeping ruptured disc
`is especially true when the weight of the casing in the
`fragments into debris catcher 70. Debris catcher 70 prevents
`wellbore produces more drag forces than the weight tending
`fragments from entering the float shoe and/or float collar.
`to slide the casing down the hole. When too much forceis
`Alternatively, pieces of the shattered disc may be percolated
`applied to push the casing string into the well, this can result
`to the surface. Further, because the casing ID is restored, the
`in damageto the casing string. The present float tool helps
`present method and float tool are ideal for use in ball-drop
`systems.
`to address some ofthese problems.
`In the method of installing a casing string, the casing
`Oncethe disc has been ruptured, the inside diameter of the
`string 94 is initially made up at the surface. For example,
`casing string in the region of the rupture disc assembly 10 is
`when present, the debris catcher 70 is generally connected
`substantially the same as that in the remainderof the casing
`with the float shoe and/or floatcollar (e.g. the debris catcher
`string (e.g. casing ID (inner diameter) is restored following
`70 generally can be threadedly connected to float shoe 96).
`rupture of the disc). One way to accomplish this may be to
`There may be one or more pup joints or similar piping
`have the disc installed in a widened region of the casing
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`

`

`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 14 of 19
`Case 6:22-cv-01316 Document 1-2 Filed 12/30/22 Page 14 of 19
`
`US 10,465,445 B2
`
`7
`string (e.g. within radially expandedportions of one or more
`tubulars, the tubulars being connectable to other tubulars in
`the casing string). In other words, the tubular string can be
`adapted to accommodate the diameter of the rupture disc.
`Theability to restore full casing ID is useful since downhole
`tools andthe like can be deployed withoutrestriction into the
`casing string once the disc has been removed, and since
`further work can be done without the need to remove any
`part of the float tool.
`The rupture happens almost instantaneously or rapidly,
`and since full casing ID is restored, maximum flow rates can
`be quickly achieved. Moreover, because the debris is small,
`there is little danger to the casing string from the ruptured
`pieces, and the potential for clogging is minimal. Compared
`to manyprior art devices, the present float tool is inexpen-
`sive to manufacture. The rupture disc is ruptured by engage-
`ment against a region ofthe casing string (hydraulic pressure
`shears the engagementofthe rupture disc within the one or
`more tubular, allowing the disc to move downward and
`shatter). There is no need to drop a weight into the casing
`string to break the disc, for example. Moreover, there can be
`various configurationsof the rupture disc (grooved or etched
`disc, disc of thinner thickness) to improvethe breakability of
`the disc. This allows the disc to break into suitably sized
`pieces that will not impair wellbore function. Generally, it
`has been observed,
`that using the various methods and
`devices disclosed herein, the fragments of the rupture disc
`may be smaller than about one inch, or less.
`Rupture Disc Assembly
`FIG. 2 shows anillustrative implementation of rupture
`disc assembly 10, suitable for installation into the float tool
`of FIG. 1. The rupture disc assembly 10 may consist of an
`upper tubular member 16 defining an upper fluid passage-
`way 12 through its interior, coupled to a lower tubular
`member18 defining a lower fluid passageway 14 throughits
`interior, and a rupture disc 30 sealingly engaged between
`upper tubular member 16 and lower tubular member 18.
`Upper tubular member 16 may be coupled with lower
`tubular member in such a way that the outer wall of lower
`tubular member 18 overlaps at least a portion of the outer
`wall of upper tubular member 16. In the illustrated embodi-
`ment, upper tubular member 16 and lower tubular member
`18 may be mechanically joined together at 20, which may be
`a threaded connection. Various other interconnecting means
`that would be known to a person skilled in the art are
`possible. A fluid seal between upper tubular member16 and
`the lower tubular member 18 may be provided by one or
`more seals. In the illustrated embodiment, the fluid seal is
`created by an O-ring seal 22, with flanking back-up seals 24.
`Lower
`tubular member 18 may include a radially
`expandedregion 25 with a tapered internal surface 58, which
`maybe a frusto-conical surface (e.g. lead-in chamfer). The
`radially expanded region 25 is continuous with a constricted
`opening (represented by dash line 27), continuous with
`passageway 14 in lower tubular member 18. As will be
`discussed below, various surfaces on lower tubular member
`18—most notably surface 58—can form impact surfaces for
`shattering the rupture disc. Although not shown in the
`Figure, inner surface 54 of upper tubular member 16 may be
`threaded for connection to other members of the casing
`string, and outer surface 56 of lower tubular member 18 may
`also be threaded for connection to other members of the
`
`casing string (not shown). These other members of the
`casing string may have an ID similar to the diameter of the
`constricted opening 27 of lower tubular member 18. It is
`noted that the tubulars may be connectedto the casing string
`
`10
`
`20
`
`30
`
`40
`
`45
`
`55
`
`8
`using various means of connection. Upper tubular member
`16 also has a radially expanded portion 29 to help accom-
`modate disc 30.
`
`Rupture disc 30 may be sealingly engaged between upper
`tubular member 16 and lower tubular member 18, concen-
`trically disposed traverse to the longitudinal axis of the
`upper and lower tubular members. In the illustrated embodi-
`ment, a portion 32 of rupture disc 30 is a hollow, hemi-
`spherical dome, with a concave surface 38 that faces down-
`hole and a convex surface 36 that is oriented in the up-hole
`direction. Hemispherical portion 32 is continuous with
`cylindrical portion 34 which terminates in a circumferential
`edge 39 ‘having a diameter that
`is similar to the inner
`diameter of the radially expanded region 25 of lower tubular
`member18 at shoulder 26.
`The upper and lower tubulars can be understood to more
`generally constitute upper and lowerportions of the overall
`assembly 10.
`In the illustrated embodiment, the diameter of disc 30 at
`edge 39 may be 4.8 inches, for example. The diameterof the
`top of the radially expanded region 25 of lower tubular
`member 18 may be similar. The diameter of constricted
`opening 27 of lower tubular member 18 may be 4.5 inches
`(which is a common ID for