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`U.S. UTILITY PATENT APPLICATION
`PATENT DATE
`O.IP.E.
`SCANNED P £A QA. d41 1JAN 3 0 ZD0
`
`SECTOR CLASS
`
`SUBCLASS
`
`ART UNIT
`
`EXAMINER
`
`/ J 7FILED WITH:
`
`DISK (GF) [] FICHE
`(Attaclied in pocket on right inside flap)
`
`PREPARED AND APPROVED FOR ISSUE
`
`ISSUING CLASSIFICATION
`
`CLASS
`
`CROSS REFERENCE(S)
`
`SUBCLASS (ONE SUBCLASS PER BLOCK)
`
`CLASS
`
`I
`
`ORIGINAL
`
`SUBCLASS -
`
`INTERNATIONAL CLASSIFICATION
`
`/ 77 / /i 14/
`2 ,&/'/
`-- --
`/
`--
`/1
`-- --
`-
`1c lq-0z
`11TERMINAL
`U DISCLAIMER
`
`DRAWINGS
`
`-(Assistant Examiner)
`99
`
`FprrnDrawros( htse ) —,_qg 1'fl
`I2-
`
`Sheets Drwg.
`
`I Figs. Drwg. I Print Fig.
`
`Continued on Issue Slip Inside File Jacket
`
`CLAIMS ALLOWED
`Print Claim for 0G.
`
`Total Claims
`
`NOTICE OF ALLOWANCE MAILED
`
`,, (Date)
`
`_ ) a c.9
`
`LII a) The term of this patent
`subsequent to
`has been disclaimed.
`
`(date)
`
`b) The term of this patent shall
`not extend beyond the expiration date
`of U.S Patent. No.
`
`..,,S? ._-.
`
`ISSUE FEEI.)?
`
`Date Paid
`
`Amount Due
`
`(,osao1/7ç"_or)
`
`ISSUE BATCH NUMBER
`
`V V -
`WARNING:
`The information disclosed herein may be restricted. Unauthorized disclosure may be prohibited by the United States Code Title 35, Sections 122, 181 and 368.
`Possession outside the U.S. Patent & Trademark Office Is restdcted to authoflzed employees and contractors only.
`
`of
`c) The terminal
`this patent have been disclaimed.
`
`FRANK ISAY
`PRIMARY E)MINER
`•
`
`(Primary Examiner)
`
`(Date)
`
`struS Examiner) 1' /'te)
`
`Form PTO-436A
`(Rev 10/97)
`
`Format DrawtflgS (_sMS) seL_.
`
`(LABEL AREA)
`
`Fe In File
`
`(FACE)
`
`OSES_000001
`
`Greene’s Energy Group, LLC v. Oil States Energy Services, LLC, IPR2014-00216, Ex. 2019
`
`
`
`INbTLILS
`
`,J
`
`Date received
`(mci. C. of M.)
`or
`Date Mailed
`
`____
`
`PATENT APPLICATiON
`
`jc67e U.S P?O
`U9/3734e
`
`09373418
`
`CONTENTS
`Date received
`(mci. C. of M.)
`or
`Date Mailed
`
`1. ApplicatiOn — papers.
`
`••'J 4)
`
`4.
`
`5.
`
`6.
`
`7.
`
`8.
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`9.
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`10.
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`11.
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`12.
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`13.
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`14. ________________
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`15.
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`16.
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`17. _________________
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`18.
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`19.
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`20.
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`21.
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`22.
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`34.
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`35.
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`36.
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`37.
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`38.
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`39.
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`41.
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`th rI
`_____
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`—
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`____________
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`—
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`____________
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`___________
`_________
`—
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`____________
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`44.
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`46.
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`47.
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`48.
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`49.
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`50.
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`51.
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`52.
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`53.—_
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`54.
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`55.
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`57.
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`60.
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`82.
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`(FRONT)
`
`OSES_000002
`
`
`
`ISSUE SLIP STAPLF 1’ VGA (for additional cross references)
`
`\
`
`
`
`INITIALS
`
`
`POSITION
`
`
`
`
`FEE DETERMINATION “mi-mm
`O-I-P-E- CLASSIFIER ——m_
`v
`m—w
`
`
`
`
`
`INDEX OF CLAIMS
`
`.1 ................................. Rejected
`= ................................. Allowed
`
`N ................................. Non-elected
`I
`................................. Interference
`
`— (Through numeral) Canceled
`+ ................................. Restricted
`
`A ................................. Appeal
`0
`................................. Objected
`
`
`
`
`IEIlI-IIIIII
`IEIIIII-IIII
`lfill-III-III
`IEIIIIIIIIII
`IEIII-II-III
`Ell-III...-
`Ell-III...-
`IEIIIIIIIIII
`IEIIIIIIIIII
`IEIII-II-III
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`IEIIIIIIIIII
`IEIIIIII-III
`IEIIII-IIIII
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`ZEIIIIIIIIII
`31IIIIIIIIII
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`@E-II-IIIII
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`
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`EEK-IIIIIIII
`mEEIIIIII-II
`EEK-IIIIIIII
`Hal-IIIIIIII
`IEIIIIIIIIII
`IEIIII-IIIII
`IflI-IIIII-II
`IEIIII-IIIII
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`IEIIIIIIIIII
`IEII-IIIIIII
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`IHIIIIIIIIII
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`
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`
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`
`
`IE-I-I-I-III Im-I-I-I-I-I IE-Il-I-I-II
`
`If more than 150 claims or 10 actions
`
`staple additional sheet here
`
`(LEFT INSIDE)
`
`OSES_000003
`
`
`
`
`
`OSES_000003
`
`
`
`C'ass
`
`/(
`
`SEARCHED
`
`NOTES
`(INCLUDING SEARCH STRATEGY)
`
`Sub.
`
`Date
`
`Exmr.
`
`Date
`
`Exmr.
`
`775i
`
`fjcP
`
`2- ±
`
`3'Qc3
`
`INTERFERENCE SEARCHED
`Sub.
`Exmr.
`Class
`Date
`
`a
`
`VLQ
`
`%',/,J ?
`
`(RIGHT OUTSIDE)
`
`OSES_000004
`
`
`
`PATENT APPLICATION SERIAL NO.
`
`U.S. DEPARTMENT OF COMMERCE
`PATENT AND TRADEMARK OFFICE
`FEE RECORD SHEET
`
`08/18/1999 HYILLRRI 00000047 09373418
`
`/
`380.00 (P
`63.00(P'
`
`PTO-1556
`
`(5/87)
`
`*U.S. GPO: 1998-433-214/80404
`
`OSES_000005
`
`
`
`SERIAL NUMBER
`
`FILING DATE
`
`CLASS
`
`GROUP ART UNIT
`
`ATTORNEY DOCKET NO.
`
`09/373,418
`
`08/12/99
`
`166
`
`3672
`
`SXA—18
`
`L. MURRAY DALLAS, FAIRVIEW, TX.
`
`I.z
`
`0
`
`* * CONTINUING
`
`DOMESTIC DATA* ***** * ****** ********
`
`,4/c,ne
`
`VER7D
`
`**371 (NAT'L
`
`STAGE) DATA********************
`
`VERID
`
`**FOREIGN APPLICATIONS************
`
`VEIED
`
`IF REQUIRED, FOREIGN FILING LICENSE GRANTED 08/27/99 ** SMALL ENTITY **
`
`Foreign Priority cloimed
`35 USC 119 (a-d) conditions met
`Verified and Acknowledged
`
`DORITY & MANNING
`P0 BOX 1449
`GREENVILLE SC 29602-1449
`
`LOCKDOWN MECHANISM FOR WELL TOOLS REQUIRING FIXED-POINT PACKOFF
`
`(I)
`U,Ui
`0
`
`Ui
`
`(Filing)
`(Processing
`(Issue)
`
`Ext. of time)
`
`All Fees
`1.16 Fees
`1 .17 Fees
`1 .1 Fees
`Other
`Ci&dt
`
`00
`
`FILING FEE
`RECLVED
`
`$443
`
`Authority
`to
`
`FEES:
`No.
`NO.
`
`has been given in Paper
`charge/credit DEPOSIT ACCOUNT
`for the following:
`
`OSES_000006
`
`
`
`ABSTRACT OF THE DISCLOSURE
`
`An apparatus for securing a mandrel of a well
`
`tool in an operative position in which the mandrel is
`
`packed off against a fixed—point in the well is
`
`described. The apparatus includes a mechanical lockdown
`
`mechanism to secure the tool to the welihead and maintain
`
`the mandrel in proximity to the fixed—point for packoff,
`
`and a mechanical or a hydraulic mechanism to move the
`
`mandrel into the operative position while the mechanical
`
`lockdown mechanism is in a lockdown position. A second
`
`mechanical locking mechanism is provided to ensure the
`
`mandrel is maintained in the operative position in the
`
`event that hydraulic pressure is lost.
`
`The invention
`
`provides a mechanism to lock down well tools requiring
`
`fixed-point packoff in a well and advantageously improves
`
`the range of adjustment of the lockdown mechanism so that
`
`the length of a mandrel may be less precisely matched to
`
`a distance from a top of the welihead to the fixed-point
`
`in the well.
`
`— 43 —
`
`OSES_000007
`
`
`
`PATENT
`
`ATTORNEY DOCKET NO.:
`
`SXA-18
`
`UNITED STATES PATENT APPLICATION
`
`ENTITLED
`
`LOCKDOWN MECHANISM FOR WELL TOOLS
`
`REQUIRING FIXED—POINT PACKOFF
`
`BY
`
`L. MURRAY DALLAS
`
`OSES_000008
`
`
`
`___ -
`
`LOCKDOWN MECHANISM FOR WELL TOOLS REQUIRING
`
`FIXED-POINT PACKOFF
`
`TECHNICAL FIELD
`
`5
`
`The present invention relates to equipment for
`
`servicing oil and gas wells and, in particular, to an
`
`apparatus and method for securing a mandrel of a well
`
`tool in an operative position in which the mandrel is
`
`packed-off against a fixed-point in the well.
`
`10
`
`BACKGROUND OF THE INVENTION
`
`Most oil and gas wells eventually require some
`
`form of stimulation to enhance hydrocarbon flow and make
`
`or keep them economically viable.
`
`The servicing of the
`
`15
`
`oil and gas wells to stimulate production requires the
`
`pumping of fluids under high pressure.
`
`The fluids are
`
`generally corrosive and abrasive because they are
`
`frequently laden with corrosive acids and abrasive
`
`proppants such as sharp sand. Consequently, such fluids
`
`20 can cause irreparable damage to welihead equipment if
`
`they are pumped directly through the spool and the
`
`various valves that make up the wellhead.
`
`To prevent
`
`—1—
`
`OSES_000009
`
`
`
`such damage, wellhead isolation tools have been used and
`
`various configurations are well known in the art.
`
`A general principle of welihead isolation in
`
`the prior art is to insert a mandrel of the tools through
`
`5 the various valves and spools of the wellhead to isolate
`
`those components from the elevated pressures and the
`
`corrosive and abrasive fluids used in the well treatment
`
`to stimulate production. A top end of the mandrel is
`
`connected to one or more high pressure valves through
`
`10
`
`which the stimulation fluids are pumped.
`
`A packoff
`
`assembly is usually provided at a bottom end of the
`
`mandrel for achieving a fluid seal against the inside of
`
`the production tubing or casing so that the wellhead is
`
`completely isolated from the stimulation fluids.
`
`The
`
`15 length of the mandrel need not be precise because the
`
`location of the packoff assembly in the production tubing
`
`or casing is irrimaterial so long as the mandrel is
`
`inserted into the production tubing or casing and a fluid
`
`tight seal is achieved between the production tubing or
`
`20 casing and the packoff assembly.
`
`However, a packoff affixed to a bottom end of
`
`the mandrel which seals against the inside of the
`
`production tubing or casing, limits the internal diameter
`
`—2--
`
`OSES_000010
`
`
`
`of the mandrel and, consequently, the flow rate at which
`
`stimulation fluids may be pumped into the well.
`
`To
`
`overcome this problem, Applicant invented an improved
`
`mandrel for a wellhead isolation tool described in
`
`5
`
`co—pending United States Patent Application Serial No.
`
`08/837,574 which was filed on April 21, 1997 and entitled
`
`APPTUS FOR INCREASING THE TNSFER TE OF PRODUCTION
`
`STIMULATION FLUIDS THROUGH THE WELLHEAD OF A HYDROCARBON
`
`WELL. The apparatus described in that patent application
`
`10 includes a mandrel for a wellhead isolation tool and a
`
`tubing hanger for use in conjunction with the mandrel.
`
`The mandrel includes an annular seal bonded to an outside
`
`wall above the bottom end of the mandrel.
`
`The annular
`
`seal cooperates with a sealing surface in the top end of
`
`15 the tubing hanger to isolate the welihead equipment from
`
`high pressures and corrosive and abrasive materials
`
`pumped into the well during a well treatment to stimulate
`
`production.
`
`The novel construction of the mandrel and
`
`the tubing hanger eliminates the requirement for a
`
`20 packoff assembly attached to the bottom of the mandrel
`
`and thereby permits the mandrel to have a larger internal
`
`diameter for increasing the transfer rate of the
`
`production stimulation fluids through the welihead.
`
`The
`
`—3—
`
`OSES_000011
`
`
`
`axial length of the sealing surface in the tubing hanger
`
`available for packoff is limited and, therefore, the
`
`length of the mandrel is determined, to a large extent,
`
`by a distance from the top of the tubing hanger to the
`
`5
`
`top of the welihead.
`
`Applicant describes another improved mandrel
`
`for a welihead isolation tool in United States Patent
`
`Application Serial No. O4(cid:17)6', 2i1 which was filed on
`
`July 16, 1999 and entitled WELLHEAD ISOLATION TOOL AND
`
`10 METHOD OF USING SANE, which is incorporated herein by
`
`reference.
`
`The welihead isolation tool includes a
`
`mandrel that is inserted into a welihead. The mandrel is
`
`seated against an annular step above back pressure valve
`
`threads in a tubing hanger to isolate the pressure
`
`15
`
`sensitive components of the welihead from fluid pressure
`
`used in the well treatment and has a lower section
`
`extending past the back pressure valve threads and tubing
`
`threads into the tubing to protect the threads from
`
`washout. The annular step above the back pressure valve
`
`20 threads in the tubing hanger is a fixed-point for packoff
`
`of the mandrel and, therefore, a length of the mandrel is
`
`determined by the distance from the annular step to the
`
`top of the welihead and a lockdown mechanism for securing
`
`—4-.
`
`OSES_000012
`
`
`
`the wellhead isolation tool to the welihead preferably
`
`provides a range of adjustment to compensate for
`
`variations in the position of the top end of the mandrel
`
`when the mandrel is packed off in different weliheads.
`
`5
`
`Another example of a well tool in an operative
`
`position in which the mandrel of the well tool is
`
`packed-off against a fixed-point in the well is described
`
`in Applicant's United States Patent No. 5,819,851 which
`
`issued on October 13,
`
`1998 and is entitled BLOWOUT
`
`10 PREVENTER PROTECTOR FOR USE DURING HIGH PRESSURE OIL/GAS
`
`WELL STIMULATION.
`
`The blowout preventer protector
`
`described in that patent includes a mandrel that is
`
`forcibly reciprocatable in an annular cavity of a spool.
`
`The mandrel is stroked down through a blowout preventer
`
`15
`
`and packed off at the bottom end against a bit guide that
`
`is attached to a top end of the casing to protect the
`
`blowout preventer from exposure to fluid pressure as well
`
`as abrasive and corrosive well stimulation fluids.
`
`The
`
`bit guide attached to the top end of the casing provides
`
`20 a fixed-point for packoff of the mandrel.
`
`It is apparent from the examples described
`
`above that, as a result of new tools being invented and
`
`new technology being developed, there is a need for a
`
`—5—
`
`OSES_000013
`
`
`
`lockdown mechanism for securing a well tool requiring a
`
`fixed-point packoff in an operative position in the well.
`
`The blowout preventer protector described in
`
`United States Patent No. 5,819,851 includes a mandrel
`
`5
`
`that is integrally incorporated with a hydraulic setting
`
`tool.
`
`The mandrel is not separable from the hydraulic
`
`setting
`
`tool
`
`and the setting tool
`
`is
`
`used to
`
`hydraulically lock the mandrel in an operative position.
`
`The mandrel can be secured at any location within the
`
`10
`
`annular cavity by maintaining the hydraulic pressure in
`
`the annular cavity after the mandrel is packed-off
`
`against the bit guide.
`
`The stroke of the hydraulic
`
`setting tool is used for inserting the mandrel through
`
`the blowout preventer, and also provides compensation for
`
`15 variations in a distance from the bit guide to the top of
`
`the blowout preventer when the mandrel is inserted
`
`through different wellheads.
`
`The blowout preventer
`
`protector is widely accepted in the industry and the
`
`hydraulic setting tool is very convenient for securing a
`
`20 mandrel of a well tool in the operative position
`
`requiring fixed-point packoff in the well.
`
`However, the
`
`setting tool must be fairly long to provide sufficient
`
`stroke.
`
`Furthermore, the setting tool is not removable
`
`—6—
`
`/
`
`OSES_000014
`
`
`
`from the mandrel during a well treatment to stimulate
`
`production.
`
`Consequently,
`
`the
`
`blowout
`
`preventer
`
`protector has a high profile. A well tool with a high
`
`profile is not convenient because access to equipment
`
`5 mounted thereto, such as a high pressure valve, is
`
`impeded by the height of the valve above ground.
`
`In
`
`addition, a hydraulic lockdown mechanism is considered
`
`less secure than a mechanical lockdown mechanism.
`
`The
`
`hydraulic lockdown mechanism is dependent on maintenance
`
`10
`
`of the hydraulic fluid pressure in the setting tool.
`
`Since fluid pressure may be lost for a variety of
`
`reasons, persons in the industry are generally less
`
`inclined to endorse or accept a hydraulic lockdown
`
`mechanism.
`
`15
`
`A mechanical lockdown mechanism having a range
`
`of adjustment is used for the well tools described in
`
`Applicant's co-pending United States patent application
`
`filed on June 23, 1999 and the application filed on
`
`July 16, 1999 referenced above.
`
`The mechanical lockdown
`
`20 mechanism described in the above two patent applications
`
`is for securing a mandrel of well tools in an operative
`
`position requiring fixed-point packoff in the well, and
`
`provides a broad range of adjustment to compensate for
`
`—7—
`
`OSES_000015
`
`
`
`variations in the height of different wellheads to which
`
`the well tool is mounted.
`
`The mechanical lockdown
`
`mechanism includes a base member that is adapted to be
`
`mounted to a top of the wellhead, the base member having
`
`5
`
`a central passage to permit the insertion and the removal
`
`of the mandrel. The passage is surrounded by an integral
`
`sleeve having an elongated spiral thread for engaging a
`
`lockdown nut that is adapted to secure the mandrel in the
`
`operative position.
`
`The spiral thread on the integral
`
`10
`
`sleeve and the lockdown nut have a length adequate to
`
`ensure
`
`safe
`
`operation
`
`at
`
`well
`
`stimulation
`
`fluid
`
`pressures.
`
`At least one of the spiral threads on the
`
`integral sleeve and the lockdown nut has a length
`
`adequate to provide a significant range of adjustment to
`
`15 compensate for variation in a distance between the top of
`
`the welihead and the fixed-point for packoff in the well
`
`when the tool is mounted to different wellheads.
`
`The
`
`mechanical lockdown mechanism is separated from the
`
`hydraulic setting tool and,
`
`therefore, permits the
`
`20 setting tool to be removed from the well tool after the
`
`mandrel is locked down in the operative position.
`
`The
`
`tools therefore provide a low profile to facilitate well
`
`stimulation operations.
`
`The advantages also include the
`
`—8--
`
`OSES_000016
`
`
`
`security of a mechanical lockdown mechanism.
`
`Therefore,
`
`there exists a need for a lockdown mechanism for securing
`
`a mandrel of a well tool in an operative position
`
`requiring fixed—point packoff in the well which provides
`
`5
`
`a broader range of adjustment while ensuring a secure
`
`mechanical lockdown for maximum security.
`
`SUMMARY OF THE INVENTION
`
`It is a primary object of the invention to
`
`10
`
`provide a lockdown mechanism for securing a mandrel of a
`
`well tool in an operative position in which the mandrel
`
`is packed—off against a fixed-point in the well.
`
`It is another object of the invention to
`
`provide a lockdown mechanism for securing a mandrel of
`
`15
`
`the well tool in an operative position requiring fixed-
`
`point packoff in the well, the lockdown mechanism having
`
`a low profile for easy access to a high pressure valve
`
`during use while the tool is in the operative position.
`
`It is a further object of the invention to
`
`20 provide a lockdown mechanism for securing a mandrel of
`
`the well tool in an operative position requiring
`
`fixed-point packoff in the well which is convenient to
`
`use.
`
`—9—
`
`OSES_000017
`
`
`
`It is yet a further object of the invention to
`
`provide a lockdown mechanism for securing a mandrel of a
`
`well tool in an operative position requiring fixed-point
`
`packoff in the well which combines a hydraulic lockdown
`
`5 mechanism with a mechanical lockdown mechanism.
`
`In accordance with one aspect of the invention,
`
`there is provided an apparatus for securing a mandrel of
`
`a
`
`well tool
`
`in an operative position requiring
`
`fixed-point packoff in the well, comprising a first and a
`
`10
`
`second lockdown mechanism arranged so that the mandrel is
`
`locked in the operative position only when both the first
`
`and the second lockdown mechanisms are in respective
`
`lockdown positions; the first lockdown mechanism adapted
`
`to detachably maintain the mandrel in proximity to the
`
`15 fixed-point packoff when in the lockdown position, the
`
`first lockdown mechanism including a base member for
`
`connection to a welihead of the well and a locking member
`
`for detachably engaging the base member; and the second
`
`lockdown mechanism having a range of adjustment adequate
`
`20
`
`to ensure that the mandrel can be moved into the
`
`operative position and locked down in the operative
`
`position while the first lockdown mechanism is in the
`
`lockdown position.
`
`— 10 —
`
`1/
`
`OSES_000018
`
`
`
`The
`
`second
`
`lockdown
`
`mechanism preferably
`
`comprises a first member connected to the mandrel and a
`
`second member connected to the locking member of the
`
`first lockdown mechanism, the first and second members
`
`5
`
`being linked to permit movement with respect to each
`
`other within the range of adjustment.
`
`In accordance with one embodiment of the
`
`invention, the second member of the second lockdown
`
`mechanism includes at least one threaded bolt connected
`
`10
`
`at a fixed end to the locking member of the first
`
`lockdown mechanism and the first member of the second
`
`lockdown mechanism has at least one bore to permit the at
`
`least one threaded bolt to pass therethrough without
`
`resistance,
`
`the at least one threaded bolt being
`
`15
`
`prevented from being withdrawn from the bore by a lock
`
`nut which is adapted to be rotated from a free end of the
`
`threaded bolt towards the fixed end to lock the second
`
`lockdown mechanism in the lockdown position.
`
`In accordance with another embodiment of the
`
`20 invention, the first member of the second lockdown
`
`mechanism includes a piston fixed to the mandrel and the
`
`second member of the second lockdown mechanism includes a
`
`cylinder connected with the locking member of the first
`
`— 11 —
`I /(4
`
`OSES_000019
`
`
`
`lockdown mechanism, the piston being adapted to be
`
`reciprocated within the cylinder using fluid pressure.
`
`In accordance with another aspect of the
`
`invention, there is provided an apparatus used for
`
`5
`
`securing a mandrel of a well tool in an operative
`
`position in which the mandrel is packed off against a
`
`fixed-point in the well, comprising a mechanical lockdown
`
`mechanism for detachably securing the well tool to a
`
`wellhead of the well and maintaining the mandrel in
`
`10 proximity to the fixed-point for packoff, the mechanical
`
`lockdown mechanism including a base member for connection
`
`of the welihead and a locking member for detachably
`
`engaging the base member; a hydraulic mechanism including
`
`a cylinder and a piston which may be reciprocated within
`
`15
`
`the cylinder using fluid pressure, the cylinder being
`
`connected to the locking member of the mechanical
`
`lockdown mechanism and the piston being fixed to the
`
`mandrel of the tool so that the mandrel may be moved to
`
`and maintained in the operative position by injecting
`
`20
`
`fluid pressure into the cylinder while the mechanical
`
`lockdown mechanism is in a lockdown position.
`
`The
`
`hydraulic mechanism preferably comprises a mechanical
`
`locking mechanism to ensure the mandrel is maintained in
`
`OSES_000020
`
`
`
`the operative position in the event that the fluid
`
`pressure is lost.
`
`The invention provides a lockdown mechanism
`
`with a greater range of adjustment for securing a mandrel
`
`5
`
`of a well tool in an operative position requiring
`
`fixed-point packoff in the well, in comparison with prior
`
`art lockdown mechanisms.
`
`Consequently, the length of a
`
`mandrel may be less precisely matched to a distance from
`
`the fixed-point for packoff to the top of the wellhead.
`
`10
`
`Other features and advantages will become apparent given
`
`the preferred embodiments which are described below.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention will now be further explained by
`
`15 way of example only and with reference to the following
`
`drawings, in which:
`/
`FIGs. 1 to 4 illustrate cross-sectional views
`
`of an apparatus in various working positions
`
`in
`
`accordance with a preferred embodiment of the invention;
`
`20
`
`FIGs. 5 to 7 illustrate cross—sectional views
`
`of an apparatus in various working positions
`
`in
`
`accordance with another preferred embodiment of the
`
`invention;
`
`— 13 —
`
`OSES_000021
`
`
`
`FIG. 8 is a schematic diagram of the apparatus
`
`shown in FIG. 5 mounted to a blowout preventer through
`
`which a mandrel is to be stroked and secured in an
`
`operative posItion in which the mandrel is packed off
`
`5
`
`against a bit guide mounted to a top of a casing of the
`
`well; and
`
`FIG. 9is a schematic diagram of the apparatus
`
`shown in FIG. 1 mounted to a wellhead through which a
`
`mandrel is to be stroked and secured in an operative
`
`10
`
`position in which the mandrel is packed off against an
`
`annular step in a tubing hanger of the wellhead.
`
`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
`
`FIG. 1 shows a cross-sectional view of a first
`
`15 lockdown mechanism 20 for securing a mandrel 22 of a well
`
`tool in an operative position in which the mandrel 22 is
`
`packed off against a fixed-point 24 in the well.
`
`The
`
`fixed-point for packoff may be a bit guide mounted to the
`
`top of a casing, as shown in FIG. 8, an annular step
`
`20 above back pressure valve threads of a tubing hanger, as
`
`shown in FIG.
`
`9,
`
`or any other type of fixed-point
`
`location used for packoff in a wellhead, a casing, a
`
`tubing or a downhole tool.
`
`For the purpose of convenient
`
`— 14 —
`
`OSES_000022
`
`
`
`description, the mandrel is assumed to be packed off
`
`against a fixed packoff point at the bottom of FIGs. 1
`
`through 7.
`
`The apparatus 20 includes a mandrel head 26
`
`5
`
`connected to a top end of the mandrel 22 and a base
`
`plate 28 mounted to a top of the welihead, which is
`
`indicated by line 30.
`
`The mandrel head 26 is separable
`
`from the base plate 28 to permit the mandrel 22, which is
`
`connected to the mandrel head 26, to be inserted through
`
`10
`
`the base plate 28 into the welihead until the mandrel 22
`
`reaches a fixed—point 24 for packoff.
`
`In different
`
`weliheads, a distance "D" from the fixed-point 24 for
`
`packoff to the top of the welihead may vary. Although a
`
`length "L" of the mandrel 22 may be adjusted by the
`
`15 insertion of extension
`
`sections,
`
`as
`
`described in
`
`Applicant's co—pending patent applications, it is not
`
`practical to provide a large number of extension
`
`sections, each having a different length to permit
`
`mandrels to be assembled to precisely match the distance
`
`20
`
`'SD" of each welihead. A distance "d" from a top of the
`
`welihead 30 to a top end of the mandrel 22 is a constant
`
`when the mandrel 22 is locked down to the base plate 28
`
`by a first locking member 38, as shown in FIG. 1.
`
`— 15 —
`
`/ I
`
`OSES_000023
`
`
`
`Consequently, a range of adjustment "B" is provided by a
`
`second locking member such that "B" is greater than a
`
`distance "C" between a bottom end of the mandrel 22 and
`
`the fixed packoff point 24 when the mandrel 22 is locked
`
`5
`
`down to the base plate 28, as shown in FIG. 1.
`
`The base plate 28 is preferably a circular disc
`
`which
`
`includes
`
`an
`
`integral
`
`concentric
`
`sleeve 32
`
`perpendicular to the base plate 28. A spiral thread 34
`
`on the exterior of the integral sleeve 32 mates with a
`
`10
`
`complementary spiral thread 36 on an interior surface of
`
`a lockdown nut 38.
`
`The base plate 28 and the integral
`
`sleeve 32 include a central passage 40 to permit the
`
`mandrel 22 to pass through. The lockdown nut 38 includes
`
`a top wall 42 for rotatably retaining a connector 44.
`
`15
`
`The connector 44 is a cylindrical body with an upper
`
`flange 46 and a lower flange 48 which engages the top
`
`wall 42 of the lockdown nut 38.
`
`A central passage 50
`
`through the connector 44 permits the mandrel 22 to fully
`
`pass through.
`
`The mandrel head 26 is a cylindrical body
`
`20 with an upper flange 52 for connection of equipment, such
`
`as a high pressure valve, and a lower flange 54 which is
`
`adjustably linked to the connector 44.
`
`The adjustable
`
`link between the connector 44 and the mandrel head 26 is
`
`— 16 —
`
`(1
`
`OSES_000024
`
`
`
`provided by at least two threaded bolts 56 which extends
`
`through at least two respective bores 58 in the lower
`
`flange 54.
`
`The threaded bolts 56 are connected at their
`
`fixed ends to the upper flange 46 of the connector 44.
`
`5 Nuts 60 at a free end of each bolt 56 prevents the bolt
`
`from being withdrawn from the flange 54. The bore 58 has
`
`an internal diameter slightly larger than an external
`
`diameter of the bolt 56 to permit the bolt 56 to pass
`
`therethrough without resistance.
`
`The threaded bolt 56
`
`10
`
`has an adequate length to permit the range "B" of
`
`movement of the mandrel head 56 relative
`
`to
`
`the
`
`connector 44.
`
`When the lockdown nut 38 is locked to the
`
`integral sleeve 32 by the engagement of threads 34, 36
`
`15
`
`and the mandrel head 26 is moved towards or away from the
`
`connector 44 within the range "B", the mandrel can be
`
`packed off against a fixed-point for packoff. Therefore,
`
`when the mandrel 22 may be used with weliheads having
`
`different configurations and the distance D from the
`
`20
`
`fixed-point 24 for packoff to the top of the wellhead
`
`indicated by line 30 varies by a distance "C" that is not
`
`greater than the range of adjustment "B", that is,
`
`0 < C < B, the apparatus 20 is adapted to be locked down
`
`— 17 -
`I
`
`OSES_000025
`
`
`
`in the operative position in which a bottom end of the
`
`mandrel 22 is packed off against the fixed-point 24 for
`
`packoff.
`
`As will be understood by those skilled in the
`
`5
`
`art, in order to safely restrain fluid pressure during a
`
`well treatment to stimulate production, the number of the
`
`threaded bolts 56, nuts 60 and bores 58 is generally more
`
`than two. The bolts 56 are circumferentially spaced from
`
`each other, the number of each being dictated by the
`
`10 fluid pressures to be restrained and the quality of
`
`materials used. The periphery of the lower flange 54 of
`
`the mandrel head 26 extends beyond the flange 52 of the
`
`mandrel head 26 so that the upper flange 52 does not
`
`interfere with the threaded bolts 56 as the mandrel
`
`15 head 26 is moved towards the connector 44.
`
`The mandrel
`
`head 26 has a central passage 62 in fluid cornrrtunication
`
`with the mandrel 22.
`
`The passage 62 has a diameter not
`
`smaller than the internal diameter of the mandrel 22 for
`
`a full access to the mandrel.
`
`A spiral thread is
`
`20 provided at the lower end of the central passage 62 for
`
`connection of the threaded top end of the mandrel 22. A
`
`sealing mechanism (not shown) is provided in the threaded
`
`connection between the top end of the mandrel 22 and the
`
`— 18 —
`
`OSES_000026
`
`
`
`mandrel head 26 to prevent well fluids from escaping to
`
`atmosphere.
`
`The central passage 40 through the base
`
`plate 28 has a recessed lower region for receiving a
`
`steel
`
`spacei 64
`
`and
`
`packing
`
`rings 66
`
`preferably
`
`5
`
`constructed of brass, rubber and fabric.
`
`The steel
`
`spacer 64 and packing rings 66 define a passage of the
`
`same diameter as the periphery of the mandrel 22.
`
`The
`
`steel spacer 64 and the packing rings 66 are removable
`
`and may be interchanged to accommodate different sizes of
`
`10 mandrel 22. The steel spacer 64 and the packing rings 66
`
`are retained in the recessed region by a retainer nut 68.
`
`The combination of the steel spacer 64, packing rings 66
`
`and the retainer nut 68 provide a fluid seal to prevent
`
`the passage to atmosphere of well fluids between the
`
`15 exterior of the mandrel 22 and the interior of the
`
`welihead when the mandrel 22 is inserted into the
`
`wellhead.
`
`FIG. 2 shows a cross—sectional view of the
`
`apparatus 20 in a working position in which the nuts 60
`
`20
`
`are at the free end of the threaded bolts 56 and the
`
`lockdown nut 38 is disengaged from the base plate 28.
`
`In
`
`this condition, the base plate 28 can be mounted on the
`
`top of the welihead while the other parts of the
`
`— 19 —
`
`OSES_000027
`
`
`
`apparatus 20 are connected to the top end of mandrel 22
`
`and are moved with the mandrel 22 when the mandrel 22 is
`
`inserted into the welihead by a setting tool, which will
`
`be described in more detail with reference to FIGs. 8
`
`5 and 9.
`
`When the apparatus 20, except for the base
`
`plate 28,
`
`is moved downwardly as the mandrel 22 is
`
`inserted through the wellhead, the upper flange 46 of the
`
`connector 44 is spaced from the lower flange 54 of the
`
`mandrel head 26, as shown in FIG. 2. For safe engagement
`
`10
`
`to restrain the high fluid pressures during a well
`
`treatment to stimulate production, threads 34-36 are
`
`engaged a distance "A" by rotating the lockdown nut 38.
`
`At this stage, the bottom end of the mandrel 22 is still
`
`above the fixed—point 24 for packoff by the distance "C",
`
`15 as shown in FIG. 1.
`
`After the lockdown nut 38 is fully
`
`engaged as shown in FIG. 3, the mandrel 22 is further
`
`stroked down until the bottom end of the mandrel 22 packs
`
`off against the fixed-point 24.
`
`The nuts 60 are then
`
`rotated down against the lower flange 54 of the mandrel
`
`20 head 26 to prevent a fluid seal on the lower end of
`
`mandrel 22 (not shown) from being forced away from the
`
`fixed-point 24 for packoff after the setting tool is
`
`— 20 —
`
`OSES_000028
`
`
`
`removed from the wellhead and pressurized fluids are
`
`injected into the well.
`
`Alternatively, the mandrel 22 with connected
`
`mandrel head 26 may be stroked downwardly without
`
`5
`
`engaging the lockdown nut 38 with the base plate 28 as
`
`shown in FIG. 4 until the bottom end of the mandrel 22 is
`
`packed off in an operative position against the
`
`fixed-point 24 for packoff. The lockdown nut 38 is then
`
`rotated to engage the threads 34 on the integral
`
`10
`
`sleeve 32.
`
`The final locked position is the same as
`
`shown in FIG. 3.
`
`Therefore, the nuts 60 are turned down
`
`against the lower flange 54 of the mandrel head 26 to
`
`lock the apparatus 20 in the operative position.
`
`FIG.
`
`5
`
`is a cross—sectional view of an
`
`15 apparatus 70
`
`in
`
`accordance with another
`
`preferred
`
`embodiment of the invention. The apparatus 70 includes a
`
`mandrel head 26 threadedly connected to a top end of the
`
`mandrel 72 and a base plate 28 adapted to be mounted to
`
`the top of the welihead, indicated by line 30.
`
`The
`
`20 mandrel head 26, base plate 28 and other parts indicated
`
`by reference numerals corresponding to those shown in
`
`FIG. 1 are respectively identical to the corresponding
`
`parts of the apparatus 70.
`
`The principal difference is
`
`— 21 —
`
`OSES_000029
`
`
`
`that the apparatus 70 includes an integral hydraulic
`
`cylinder 74 in place of
`
`the connector 44
`
`of the
`
`apparatus 20.
`
`The hydraulic cylinder 74 includes upper
`
`and lower walls 76, 78 which respectively surround the
`
`5 mandrel 72.
`
`The
`
`cylinder 74
`
`further
`
`includes
`
`sidewall 80 which defines an annular cavity 82.
`
`a
`
`A
`
`piston 84 is fixed to the mandrel 72.
`
`0-rin