(12) United States Patent
`Themig et a].
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 7,108,067 B2
`*Sep. 19, 2006
`
`US007108067B2
`
`(54)
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`(75)
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`(73)
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`(*)
`
`METHOD AND APPARATUS FOR
`WELLBORE FLUID TREATMENT
`Inventors: Daniel Jon Themig, Calgary (CA); Jim
`Fehr, Edmonton (CA)
`Assignee: Packers Plus Energy Services Inc.,
`Calgary (CA)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 219 days.
`
`Notice:
`
`This patent is subject to a terminal dis
`claimer.
`
`Appl. No.: 10/604,807
`
`Filed:
`
`Aug. 19, 2003
`
`Prior Publication Data
`
`US 2004/0118564 A1
`
`Jun. 24, 2004
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`6/1977 Sanford .................... .. 166/264
`4,031,957 A *
`7/1978 Hutchison et al. ........ .. 166/191
`4,099,563 A *
`2/1985 Vann ........................ .. 166/297
`4,499,951 A *
`3/1986 Faulkner
`4,577,702 A
`5/1995 Ehlinger et a1.
`5,411,095 A
`7/1996 Surjaatrnadja et a1.
`5,533,571 A
`6,006,838 A 12/1999 Whiteley et al.
`6,065,541 A
`5/2000 Allen
`6,189,619 B1
`2/2001 Wyatt et al.
`6,390,200 B1 *
`5/2002 Allamon et a1. .......... .. 166/376
`6,651,743 B1* 11/2003 SZarka ..................... .. 166/285
`
`OTHER PUBLICATIONS
`
`Information on RockSeal Open Hole Packers, these or similar
`packers believed to be publicly avallable in the US prior to Aug. 19,
`2002.
`
`(21)
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`(22)
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`(65)
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`(60)
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`(51)
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`(52)
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`(58)
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`Related US. Application Data
`
`* cited by examiner
`
`Provisional application No. 60/404,783, ?led on Aug.
`21, 2002.
`
`Int. Cl.
`(2006.01)
`E21B 34/14
`US. Cl. .................... .. 166/317; 166/154; 166/164;
`166/169;166/186;166/194;166/250.17;
`166/332.4; 166/334.4
`Field of Classi?cation Search .............. .. 166/ 154,
`166/164, 169, 250.17, 263, 279, 291, 296,
`166/305.1, 306, 310, 312, 317, 332.4, 334.4,
`166/373, 383, 386
`See application ?le for complete search history.
`
`Primary ExamineriZakiya W. Bates
`(74) Attorney, Agent, or F irmiBennett Jones LLP
`
`(57)
`
`ABSTRACT
`
`A tubing string assembly for ?uid treatment of a Wellbore
`includes substantially pressure holding closures spaced
`along the tubing string, Which each close at least one port
`through the tubing string Wall. The closures are openable by
`a sleeve drivable through the tubing string inner bore.
`
`12 Claims, 6 Drawing Sheets
`
`24d
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`29
`
`to sunace
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`26C
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`1 of 13
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`U.S. Patent
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`Sep. 19,2006
`
`Sheet 1 of 6
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`US 7,108,067 B2
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`‘to surface
`
`21
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`2nu,4.
`
`FIG. 1
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`U.S. Patent
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`Sep. 19, 2006
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`Sheet 2 0f 6
`
`US 7,108,067 B2
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`
`
`
`
`D3
`23
`17
`
`29
`
`to surface
`
`26C
`
`17
`
`160
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`20d
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`17
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`XXXXXXXXXXXXXXX
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`FIG. 2
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`U.S. Patent
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`Sep. 19, 2006
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`Sheet 3 6f 6
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`US 7,108,067 B2
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`21b
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`34d
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`20
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`6 N31
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`4 /
`g /-37
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`38
`/ / y/ss
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`FIG. 3
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`U.S. Patent
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`Sep. 19, 2006
`
`Sheet 4 6f 6
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`US 7,108,067 B2
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`217 217 22(0b 217
`FlG.4a
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`220a
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`22Gb
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`U.S. Patent
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`Sep. 19,2006
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`Sheet 5 of 6
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`US 7,108,067 B2
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`6 of 13
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`.35
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`

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`U.S. Patent
`
`Sep. 19,2006
`
`Sheet 6 of 6
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`US 7,108,067 B2
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`
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`
`
`
`'~~322b
`417 I:
`420b
`
`22a
`
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`.3‘ 417
`317
`317 414 4200 22c
`420d
`FIG. 7a
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`412 31732éd
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`4200
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`420d
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`FIG. 7d
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`US 7,108,067 B2
`
`1
`METHOD AND APPARATUS FOR
`WELLBORE FLUID TREATMENT
`
`BACKGROUND OF INVENTION
`
`The invention relates to a method and apparatus for
`Wellbore ?uid treatment and, in particular, to a method and
`apparatus for selective ?oW control to a Wellbore for ?uid
`treatment.
`An oil or gas Well relies on in?oW of petroleum products.
`When drilling an oil or gas Well, an operator may decide to
`leave productive intervals uncased (open hole) to expose
`porosity and permit unrestricted Wellbore in?oW of petro
`leum products. Altemately, the hole may be cased With a
`liner, Which is then perforated to permit in?oW through the
`openings created by perforating.
`When natural in?oW from the Well is not economical, the
`Well may require Wellbore treatment termed stimulation.
`This is accomplished by pumping stimulation ?uids such as
`fracturing ?uids, acid, cleaning chemicals and/or proppant
`laden ?uids to improve Wellbore in?oW.
`In one previous method, the Well is isolated in segments
`and each segment is individually treated so that concentrated
`and controlled ?uid treatment can be provided along the
`Wellbore. Often, in this method a tubing string is used With
`in?atable element packers thereabout Which provide for
`segment isolation. The packers, Which are in?ated With
`pressure using a bladder, are used to isolate segments of the
`Well and the tubing is used to convey treatment ?uids to the
`isolated segment. Such in?atable packers may be limited
`With respect to pressure capabilities as Well as durability
`under high pressure conditions. Generally, the packers are
`run for a Wellbore treatment, but must be moved after each
`treatment if it is desired to isolate other segments of the Well
`for treatment. This process can be expensive and time
`consuming. Furthermore, it may require stimulation pump
`ing equipment to be at the Well site for long periods of time
`or for multiple visits. This method can be very time con
`suming and costly.
`Other procedures for stimulation treatments use tubing
`strings Without packers such that tubing is used to convey
`treatment ?uids to the Wellbore, the ?uid being circulated up
`hole through the annulus betWeen the tubing and the Well
`bore Wall or casing.
`The tubing string, Which conveys the treatment ?uid, can
`include ports or openings for the ?uid to pass therethrough
`into the borehole. Where more concentrated ?uid treatment
`is desired in one position along the Wellbore, a small number
`of larger ports are used. In another method, Where it is
`desired to distribute treatment ?uids over a greater area, a
`perforated tubing string is used having a plurality of spaced
`apart perforations through its Wall. The perforations can be
`distributed along the length of the tube or only at selected
`segments. The open area of each perforation can be pre
`selected to control the volume of ?uid passing from the tube
`during use. When ?uids are pumped into the liner, a pressure
`drop is created across the siZed ports. The pressure drop
`causes approximate equal volumes of ?uid to exit each port
`in order to distribute stimulation ?uids to desired segments
`of the Well.
`In many previous systems, it is necessary to run the tubing
`string into the bore hole With the ports or perforations
`already opened. This is especially true Where a distributed
`application of treatment ?uid is desired such that a plurality
`of ports or perforations must be open at the same time for
`passage therethrough of ?uid. This need to run in a tube
`
`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`2
`already including open perforations can hinder the running
`operation and limit usefulness of the tubing string.
`Some sleeve systems have been proposed for ?oW control
`through tubing ports. HoWever, the ports are generally
`closely positioned such that they can all be covered by the
`sleeve.
`
`SUMMARY OF INVENTION
`
`A method and apparatus has been invented Which pro
`vides for selective communication to a Wellbore for ?uid
`treatment. In one aspect, the method and apparatus provide
`for the running in of a ?uid treatment string, the ?uid
`treatment string having ports substantially closed against the
`passage of ?uid therethrough, but Which are openable When
`desired to permit ?uid ?oW into the Wellbore. The apparatus
`and methods of the present invention can be used in various
`borehole conditions including open holes, lined or cased
`holes, vertical, inclined or horizontal holes, and straight or
`deviated holes.
`In one embodiment, there is provided an apparatus for
`?uid treatment of a borehole, the apparatus comprising a
`tubing string having a long axis, a plurality of closures
`accessible from the inner diameter of the tubing string, each
`closure closing a port opened through the Wall of the tubing
`string and preventing ?uid ?oW through its port, but being
`openable to permit ?uid ?oW through its port and each
`closure openable independently from each other closure and
`a port opening sleeve positioned in the tubing string and
`driveable through the tubing string to actuate the plurality of
`closures to open the ports.
`The sleeve can be driven in any Way to move through the
`tubing string to actuate the plurality of closures. In one
`embodiment, the sleeve is driveable remotely, Without the
`need to trip a Work string such as a tubing string, coiled
`tubing or a Wire line.
`In one embodiment, the sleeve has formed thereon a seat
`and the apparatus includes a sealing device selected to seal
`against the seat, such that ?uid pressure can be applied to
`drive the sleeve and the sealing device can seal against ?uid
`passage past the sleeve. The sealing device can be, for
`example, a plug or a ball, Which can be deployed Without
`connection to surface. This embodiment avoids the need for
`tripping in a Work string for manipulation.
`In one embodiment, the closures each include a cap
`mounted over its port and extending into the tubing string
`inner bore, the cap being openable by the sleeve engaging
`against. The cap, When opened, permits ?uid ?oW through
`the port. The cap can be opened, for example, by action of
`the sleeve breaking open the cap or shearing the cap from its
`position over the port.
`In another embodiment, the closures each include a port
`closure sleeve mounted over at least one port and openable
`by the sleeve engaging and moving the port-closure sleeve
`aWay from its associated at least one port. The port-closure
`sleeve can include, for example, a pro?le on its surface open
`to the tubing string and the port-opening sleeve includes a
`locking dog biased outWardly therefrom and selected to
`engage the pro?le on the port-closure sleeve such that the
`port-closure sleeve is moved by the port opening sleeve. The
`pro?le is formed such that the locking dog can disengage
`therefrom, permitting the sleeve to move along the tubing
`string to a next port-closure sleeve.
`In one embodiment, the apparatus can include a packer
`about the tubing string. The packers can be of any desired
`
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`US 7,108,067 B2
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`3
`type to seal between the Wellbore and the tubing string. For
`example, the packer can be a solid body packer including
`multiple packing elements.
`In vieW of the foregoing there is provided a method for
`?uid treatment of a borehole, the method comprising: pro
`viding an apparatus for Wellbore treatment according to one
`of the various embodiments of the invention; running the
`tubing string into a Wellbore to a position for treating the
`Wellbore; moving the sleeve to open the closures of the ports
`and increasing ?uid pressure to force Wellbore treatment
`?uid out through the ports.
`In one method according to the present invention, the ?uid
`treatment is a borehole stimulation using stimulation ?uids
`such as one or more of acid, gelled acid, gelled Water, gelled
`oil, CO2, nitrogen and any of these ?uids containing prop
`pants, such as for example, sand or bauxite. The method can
`be conducted in an open hole or in a cased hole. In a cased
`hole, the casing may have to be perforated prior to running
`the tubing string into the Wellbore, in order to provide access
`to the formation.
`The method can include setting a packer about the tubing
`string to isolate the ?uid treatment to a selected section of
`the Wellbore.
`
`20
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`25
`
`A further, detailed, description of the invention, brie?y
`described above, Will folloW by reference to the folloWing
`draWings of speci?c embodiments of the invention. These
`draWings depict only typical embodiments of the invention
`and are therefore not to be considered limiting of its scope.
`In the draWings:
`FIG. 1 is a sectional vieW through a Wellbore having
`positioned therein a ?uid treatment assembly according to
`the present invention;
`FIG. 2 is a sectional vieW through a Wellbore having
`positioned therein a ?uid treatment assembly according to
`the present invention;
`FIG. 3 is a sectional vieW along the long axis of a packer
`useful in the present invention;
`FIG. 4a is a section through another Wellbore having
`positioned therein another ?uid treatment assembly accord
`ing to the present invention, the ?uid treatment assembly
`being in a ?rst stage of Wellbore treatment;
`FIG. 4b is a section through the Wellbore of FIG. 4a With
`the ?uid treatment assembly in a second stage of Wellbore
`treatment;
`FIG. 40 is a section through the Wellbore of FIG. 4a With
`the ?uid treatment assembly in a third stage of Wellbore
`treatment;
`FIG. 5 is a sectional vieW along the long axis of a tubing
`string according to the present invention containing a sleeve
`and axially spaced ?uid treatment ports;
`FIG. 6 is a sectional vieW along the long axis of a tubing
`string according to the present invention containing a sleeve
`and axially spaced ?uid treatment ports;
`FIG. 7a is a section through a Wellbore having positioned
`therein another ?uid treatment assembly according to the
`present invention, the ?uid treatment assembly being in a
`?rst stage of Wellbore treatment;
`FIG. 7b is a section through the Wellbore of FIG. 7a With
`the ?uid treatment assembly in a second stage of Wellbore
`treatment; and
`FIG. 70 is a section through the Wellbore of FIG. 7a With
`the ?uid treatment assembly in a third stage of Wellbore
`treatment; and
`
`30
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`FIG. 7d is a section through the Wellbore of FIG. 7a With
`the ?uid treatment assembly in a fourth stage of Wellbore
`treatment.
`
`DETAILED DESCRIPTION
`
`Referring to FIG. 1, a Wellbore ?uid treatment assembly
`is shoWn, Which can be used to effect ?uid treatment of a
`formation 10 through a Wellbore 12. The Wellbore assembly
`includes a tubing string 14 having a loWer end 1411 and an
`upper end extending to surface (not shoWn). Tubing string
`14 includes a plurality of spaced apart ports 17 opened
`through the tubing string Wall to permit access betWeen the
`tubing string inner bore 18 and the Wellbore. Each port 17
`includes thereover a closure that can be closed to substan
`tially prevent, and selectively opened to permit, ?uid ?oW
`through the ports.
`A port-opening sleeve 22 is disposed in the tubing string
`to control the opening of the port closures. In this embodi
`ment, sleeve 22 is mounted such that it can move, arroW A,
`from a port closed position, Wherein the sleeve is shoWn in
`phantom, axially through the tubing string inner bore past
`the ports to a open port position, shoWn in solid lines, to
`open the associated closures of the ports alloWing ?uid ?oW
`therethrough. The sliding sleeve is disposed to control the
`opening of the ports through the tubing string and is move
`able from a closed port position to a position Wherein the
`ports have been opened by passing of the sleeve and ?uid
`?oW of, for example, stimulation ?uid is permitted doWn
`through the tubing string, arroWs F, through the ports of the
`ported interval. If ?uid ?oW is continued, the ?uid can return
`to surface through the annulus.
`The tubing string is deployed into the borehole in the
`closed port position and can be positioned doWn hole With
`the ports at a desired location to effect ?uid treatment of the
`borehole.
`Referring to FIG. 2, a Wellbore ?uid treatment assembly
`is shoWn, Which can be used to effect ?uid treatment of a
`formation 10 through a Wellbore 12. The Wellbore assembly
`includes a tubing string 14 having a loWer end 1411 and an
`upper end extending to surface (not shoWn). Tubing string
`14 includes a plurality of spaced apart ported intervals 160
`to 16e each including a plurality of ports 17 opened through
`the tubing string Wall to permit access betWeen the tubing
`string inner bore 18 and the Wellbore. The ports are normally
`closed by pressure holding caps 23.
`Packers 20d to 20e are mounted betWeen each pair of
`adjacent ported intervals. In the illustrated embodiment, a
`packer 20f is also mounted beloW the loWer most ported
`interval 16e and loWer end 1411 of the tubing string.
`Although not shoWn herein, a packer can be positioned
`above the upper most ported interval. The packers are
`disposed about the tubing string and selected to seal the
`annulus betWeen the tubing string and the Wellbore Wall,
`When the assembly is disposed in the Wellbore. The packers
`divide the Wellbore into isolated segments Wherein ?uid can
`be applied to one segment of the Well, but is prevented from
`passing through the annulus into adjacent segments. As Will
`be appreciated the packers can be spaced in any Way relative
`to the ported intervals to achieve a desired interval length or
`number of ported intervals per segment. In addition, packer
`20f need not be present in some applications.
`The packers can be, as shoWn, of the solid body-type With
`at least one extrudable packing element, for example,
`formed of rubber. Solid body packers including multiple,
`spaced apart packing elements 21a, 21b on a single packer
`are particularly useful especially for example in open hole
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`5
`(unlined Wellbore) operations. In another embodiment, a
`plurality of packers are positioned in side by side relation on
`the tubing string, rather than using only one packer betWeen
`each ported interval.
`Sliding sleeves 220 to 22e are disposed in the tubing string
`to control the opening of the ports by opening the caps. In
`this embodiment, a sliding sleeve is mounted for each ported
`interval and can be moved axially through the tubing string
`inner bore to open the caps of its interval. In particular, the
`sliding sleeves are disposed to control the opening of their
`ported intervals through the tubing string and are each
`moveable from a closed port position aWay from the ports of
`the ported interval (as shoWn by sleeves 22c and 22d) to a
`position Wherein it has moved past the ports to break open
`the caps and Wherein ?uid ?oW of, for example, stimulation
`?uid is permitted through the ports of the ported interval (as
`shoWn by sleeve 22e).
`The assembly is run in and positioned doWnhole With the
`sliding sleeves each in their closed port position. When the
`tubing string is ready for use in ?uid treatment of the
`Wellbore, the sleeves are moved to their port open positions.
`The sleeves for each isolated interval betWeen adjacent
`packers can be opened individually to permit ?uid ?oW to
`one Wellbore segment at a time, in a staged treatment
`process.
`Preferably, the sliding sleeves are each moveable
`remotely, for example Without having to run in a line or
`string for manipulation thereof, from their closed port posi
`tion to their position permitting through-port ?uid ?oW. In
`one embodiment, the sliding sleeves are actuated by devices,
`such as balls 24d, 24e (as shoWn) or plugs, Which can be
`conveyed by gravity or ?uid ?oW through the tubing string.
`The device engages against the sleeve and causes it to
`move4 through the tubing string. In this case, ball 24e is
`siZed so that it cannot pass through sleeve 22e and is
`engaged in it When pressure is applied through the tubing
`string inner bore 18 from surface, ball 24e seats against and
`plugs ?uid ?oW past the sleeve. Thus, When ?uid pressure is
`applied after the ball has seated in the sleeve, a pressure
`differential is created above and beloW the sleeve Which
`drives the sleeve toWard the loWer pressure side.
`In the illustrated embodiment, the inner surface of each
`sleeve, Which is the side open to the inner bore of the tubing
`string, de?nes a seat 26e onto Which an associated ball 24e,
`When launched from surface, can land and seal thereagainst.
`When the ball seals against the sleeve seat and pressure is
`applied or increased from surface, a pressure differential is
`set up Which causes the sliding sleeve on Which the ball has
`landed to slide through the tubing string to an port-open
`position until it is stopped by, for example, a no go. When
`the ports of the ported interval 16e are opened, ?uid can ?oW
`therethrough to the annulus betWeen the tubing string and
`the Wellbore and thereafter into contact With formation 10.
`Each of the plurality of sliding sleeves has a different
`diameter seat and, therefore, each accept a different siZed
`ball. In particular, the loWer-most sliding sleeve 22e has the
`smallest diameter D1 seat and accepts the smallest siZed ball
`24e and each sleeve that is progressively closer to surface
`has a larger seat. For example, as shoWn in FIG. 1b, the
`sleeve 220 includes a seat 260 having a diameter D3, sleeve
`22d includes a seat 26d having a diameter D2, Which is less
`than D3 and sleeve 22e includes a seat 26e having a diameter
`D1, Which is less than D2. This provides that the loWest
`sleeve can be actuated to open it ports ?rst by ?rst launching
`the smallest ball 24e, Which can pass though all of the seats
`of the sleeves closer to surface but Which Will land in and
`seal against seat 26e of sleeve 22e. Likewise, penultimate
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`sleeve 22d can be actuated to move through ported interval
`16d by launching a ball 24d Which is siZed to pass through
`all of the seats closer to surface, including seat 260, but
`Which Will land in and seal against seat 26d.
`LoWer end 1411 of the tubing string can be open, closed or
`?tted in various Ways, depending on the operational char
`acteristics of the tubing string Which are desired. In the
`illustrated embodiment, the tubing string includes a pump
`out plug assembly 28. Pump out plug assembly 28 acts to
`close off end 1411 during run in of the tubing string, to
`maintain the inner bore of the tubing string relatively clear.
`HoWever, by application of ?uid pressure, for example at a
`pressure of about 3000 psi, the plug can be bloWn out to
`permit actuation of the loWer most sleeve 22e by generation
`of a pressure di?ferential. As Will be appreciated, an opening
`adjacent end 1411 is only needed Where pressure, as opposed
`to gravity, is needed to convey the ?rst ball to land in the
`loWer-most sleeve. Altemately, the loWer most sleeve can be
`hydraulically actuated, including a ?uid actuated piston
`secured by shear pins, so that the sleeve can be driven along
`the tubing string remotely Without the need to land a ball or
`plug therein.
`In other embodiments, not shoWn, end 1411 can be left
`open or can be closed, for example, by installation of a
`Welded or threaded plug.
`While the illustrated tubing string includes three ported
`intervals, it is to be understood that any number of ported
`intervals could be used. In a ?uid treatment assembly desired
`to be used for staged ?uid treatment, at least tWo openable
`ports from the tubing string inner bore to the Wellbore must
`be provided such as at least tWo ported intervals or an
`openable end and one ported interval. It is also to be
`understood that any number of ports can be used in each
`interval.
`CentraliZer 29 and other tubing string attachments can be
`used, as desired.
`The Wellbore ?uid treatment apparatus, as described With
`respect to FIG. 2, can be used in the ?uid treatment of a
`Wellbore. For selectively treating formation 10 through
`Wellbore 12, the above-described assembly is run into the
`borehole and the packers are set to seal the annulus at each
`location creating a plurality of isolated annulus Zones. Fluids
`can then pumped doWn the tubing string and into a selected
`Zone of the annulus, such as by increasing the pressure to
`pump out plug assembly 28. Alternately, a plurality of open
`ports or an open end can be provided or loWer most sleeve
`can include a piston face for hydraulic actuation thereof.
`Once that selected Zone is treated, as desired, ball 24e or
`another sealing plug is launched from surface and conveyed
`by gravity or ?uid pressure to seal against seat 26e of the
`loWer most sliding sleeve 22e, this seals off the tubing string
`beloW sleeve 22e and drives the sleeve to open the ports of
`ported interval 16e to alloW the next annulus Zone, the Zone
`betWeen packer 20e and 20], to be treated With ?uid. The
`treating ?uids Will be diverted through the ports of interval
`16e Whose caps have been removed by moving the sliding
`sleeve. The ?uid can then be directed to a speci?c area of the
`formation. Ball 24e is siZed to pass though all of the seats
`closer to surface, including seats 26c, 26d, Without sealing
`thereagainst. When the ?uid treatment through ports 16e is
`complete, a ball 24d is launched, Which is siZed to pass
`through all of the seats, including seat 260 closer to surface,
`and to seat in and move sleeve 22d. This opens the ports of
`ported interval 16d and permits ?uid treatment of the
`annulus betWeen packers 20d and 20e. This process of
`launching progressively larger balls or plugs is repeated
`until all of the Zones are treated. The balls can be launched
`
`10 of 13
`
`Ex. 2005
`IPR2016-00656
`
`

`
`US 7,108,067 B2
`
`7
`Without stopping the ?oW of treating ?uids. After treatment,
`?uids can be shut in or ?oWed back immediately. Once ?uid
`pressure is reduced from surface, any balls seated in sleeve
`seats can be unseated by pressure from beloW to permit ?uid
`?oW upWardly therethrough.
`The apparatus is particularly useful for stimulation of a
`formation, using stimulation ?uids, such as for example,
`acid, gelled acid, gelled Water, gelled oil, CO2, nitrogen
`and/or proppant laden ?uids.
`Referring to FIG. 3, a packer 20 is shoWn Which is useful
`in the present invention. The packer can be set using
`pressure or mechanical forces. Packer 20 includes extrud
`able packing elements 21a, 21b, a hydraulically actuated
`setting mechanism and a mechanical body lock system 31
`including a locking ratchet arrangement. These parts are
`mounted on an inner mandrel 32. Multiple packing elements
`21a, 21b are formed of elastomer, such as for example,
`rubber and include an enlarged cross section to provide
`excellent expansion ratios to set in oversiZed holes. The
`multiple packing elements 21a, 21b can be separated by at
`least 0.3M and preferably 0.8M or more. This arrangement
`of packing elements aid in providing high pressure sealing
`in an open borehole, as the elements load into each other to
`provide additional pack-o?.
`Packing element 21a is mounted betWeen ?xed stop ring
`34a and compressing ring 34b and packing element 21b is
`mounted betWeen ?xed stop ring 340 and compressing ring
`34d. The hydraulically actuated setting mechanism includes
`a port 35 through inner mandrel 32, Which provides ?uid
`access to a hydraulic chamber de?ned by ?rst piston 36a and
`second piston 36b. First piston 36a acts against compressing
`ring 34b to drive compression and, therefore, expansion of
`packing element 21a, While second piston 36b acts against
`compressing ring 34d to drive compression and, therefore,
`expansion of packing element 21b. First piston 36a includes
`a skirt 37, Which encloses the hydraulic chamber betWeen
`the pistons and is telescopically disposed to ride over piston
`36b. Seals 38 seal against the leakage of ?uid betWeen the
`parts. Mechanical body lock system 31, including for
`example a ratchet system, acts betWeen skirt 37 and piston
`36b permitting movement therebetWeen driving pistons 36a,
`36b aWay from each other but locking against reverse
`movement of the pistons toWard each other, thereby locking
`the packing elements into a compressed, expanded con?gu
`ration.
`Thus, the packer is set by pressuring up the tubing string
`such that ?uid enters the hydraulic chamber and acts against
`pistons 36a, 36b to drive them apart, thereby compressing
`the packing elements and extruding them outWardly. This
`movement is permitted by body lock system 31. HoWever,
`body lock system 31 locks the packers against retraction to
`lock the packing elements in their extruded conditions.
`Ring 34a includes shears 38 Which mount the ring to
`mandrel 32. Thus, for release of the packing elements from
`sealing position the tubing string into Which mandrel 32 is
`connected, can be pulled up to release shears 38 and,
`thereby, release the compressing force on the packing ele
`ments.
`FIGS. 4a to 40 shoWs an assembly and method for ?uid
`treatment, termed sprinkling, Wherein ?uid supplied to an
`isolated interval is introduced in a distributed, loW pressure
`fashion along an extended length of that interval. The
`assembly includes a tubing string 212 and ported intervals
`216a, 216b, 2160 each including a plurality of ports 217
`spaced along the long axis of the tubing string. Packers
`220a, 220b are provided betWeen each interval to form an
`isolated segment in the Wellbore 212.
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`While the ports of interval 2160 are open during run in of
`the tubing string, the ports of intervals 216b and 21611, are
`closed during run in and sleeves 222a and 222b are mounted
`Within the tubing string and actuatable to selectively open
`the ports of intervals 216a and 216b, respectively. In par
`ticular, in FIG. 4a, the position of sleeve 222b is shoWn
`When the ports of interval 216b are closed. The ports in any
`of the intervals can be siZe restricted to create a selected
`pressure drop therethrough, permitting distribution of ?uid
`along the entire ported interval.
`Once the tubing string is run into the Well, stage 1 is
`initiated Wherein stimulation ?uids are pumped into the end
`section of the Well to ported interval 2160 to begin the
`stimulation treatment (FIG. 4a). Fluids Will be forced to the
`loWer section of the Well beloW packer 220b. In this illus
`trated embodiment, the ports of interval 2160 are normally
`open siZe restricted ports, Which do not require opening for
`stimulation ?uids to be jetted therethrough. HoWever, it is to
`be understood that the ports can be installed in closed
`con?guration, but opened once the tubing is in place.
`When desired to stimulate another section of the Well
`(FIG. 4b), a ball or plug (not shoWn) is pumped by ?uid
`pressure, arroW P, doWn the Well and Will seat in a selected
`sleeve 222b siZed to accept the ball or plug. The pressure of
`the ?uid behind the ball Will push the cutter sleeve against
`any force or member, such as a shear pin, holding the sleeve
`in position and doWn the tubing string, arroW S. As it moves
`doWn, it Will open the ports of interval 216b as it passes by
`them. Sleeve 222b eventually stops against a stop means.
`Since ?uid pressure Will hold the ball in the sleeve, this
`e?fectively shuts oif the loWer segment of the Well including
`previously treated interval 2160. Treating ?uids Will then be
`forced through the neWly opened ports. Using limited entry
`or a ?oW regulator, a tubing to annulus pressure drop insures
`distribution. The ?uid Will be isolated to treat the formation
`betWeen packers 220a and 220b.
`After the desired volume of stimulation ?uids are
`pumped, a slightly larger second ball or plug is injected into
`the tubing and pumped doWn the Well, and Will seat in sleeve
`22211 which is selected to retain the larger ball or plug. The
`force of the moving ?uid Will push sleeve 222a doWn the
`tubing string and as it moves doWn, it Will open the ports in
`interval 216a. Once the sleeve reaches a desired depth as
`shoWn in FIG. 40, it Will be stopped, e?fectively shutting oif
`the loWer segment of the Well including previously treated
`intervals 216b and 2160. This process can be repeated a
`number of times until most or all of the Wellbore is treated
`in stages, using a sprinkler approach over each individual
`section.
`The above noted method can also be used for Wellbore
`circulation to circulate existing Wellbore ?uids (drilling mud
`for example) out of a Wellbore and to replace