US007428922B2
`
`(12) United States Patent
`Fripp et a].
`
`(10) Patent N0.2
`(45) Date of Patent:
`
`US 7,428,922 B2
`Sep. 30, 2008
`
`(54) VALVE AND POSITION CONTROL USING
`MAGNETORHEOLOGICAL FLUIDS
`
`(75) IIWBIIIOFSI Michael FriPP, Carrollton, TX (Us);
`Darrell Barlow, Mans?eld, TX (Us);
`
`
`.
`_
`Brandon Solleall, Dallas, , _
`
`(73) Assignee. Halllburton Energy Servlces, Houston,
`TX (US)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154 b b 465 d .
`( ) y
`ays
`
`(21) App1.No.: 10/090,054
`
`(22) Filed:
`
`Mar. 1, 2002
`
`(65)
`
`Prior Publication Data
`US 2003/0166470 A1
`Sep. 4, 2003
`
`(51) Int, Cl,
`(2006.01)
`E21B 43/1185
`(52) us. Cl. ............................... .. 166/665; 251/129.06
`(58) Field of Classi?cation Search .............. .. 166/665,
`166/666, 66.7, 135, 334.1; 137/909; 25l/l29.06,
`251/12908
`See application ?le for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`2,661,596 A 12/1953 Winslow
`4,718,494 A
`1/1988 Meek
`4,785,300 A 11/1988 Chin et al.
`5,012,740 A *
`5/1991 Hardt ....................... .. 102/216
`5,040,155 A
`8/1991 Feld
`5,048,611 A
`9/1991 Cochran
`5,073,877 A 12/1991 Jeter
`5,115,415 A
`5/1992 Mumbyetal.
`5,158,109 A * 10/1992 Hare, Sr. ................ .. 137/5143
`5,168,931 A 12/1992 Caskey et al.
`5,223,665 A
`6/1993 Burleson
`5,284,330 A
`2/1994 Carlson et al.
`5,586,084 A 12/1996 Barron et al.
`
`5,598,908 A *
`5,636,178 A
`5,787,052 A
`6,019,201 A *
`6,036,226 A *
`
`2/1997 York etal. ............... .. 192/215
`6/1997 Ritter
`7/1998 Gardner et a1.
`188/2671
`2/2000 Gordaninejad et a1.
`3/2000 Brown etal. .............. .. 280/736
`
`A 6,219,301 B1
`
`6,257,356 B1
`
`Burris, 4/2001 Moriarty
`
`7/2001 Wassell
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`1236862
`
`90002
`
`(Continued)
`OTHER PUBLICATIONS
`
`Examination Report for UK application No. GB0303599.5.
`C _
`d
`( Ommue )
`Primary Examinerilennifer H Gay
`AssistantExamineriDaniel P Stephenson
`(74) Attorney, Agent, or FirmiMarlin R. Smith
`
`(57)
`
`ABSTRACT
`
`Magnetorheological ?uids, Which solidify in response to a
`magnetic ?eld, offer the ability to simplify many of the valves
`and control systems used doWnhole in the search for and
`production of oil and gas. They lessen the need for moving
`parts, provide solid-state valves, and can provide a differen
`tial movement of ?uid through the valves by varying the
`strength of the magnetic ?eld. Combinations of permanent
`and electro-magnets can improve safety by providing valves
`that fail, When poWer is lost, in either an open or closed
`position, depending on design. A number of examples are
`given.
`
`27 Claims, 14 Drawing Sheets
`
`724
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`US 7,428,922 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`6,280,658
`6,421,298
`6,469,367
`6,514,001
`6,568,470
`6,619,388
`6,926,089
`2003/0019622
`
`8/2001
`7/2002
`10/2002
`2/2003
`5/2003
`9/2003
`8/2005
`1/2003
`
`Atarashi et al.
`Beattie et al.
`Kondo et al.
`
`YeZersky et a1. ....... .. 403/109.1
`Goodson
`DietZ
`Goodson, Jr. et al.
`Goodson, Jr. et al.
`
`GB
`GB
`
`2/2003 Goodson, Jr.
`2003/0037921 A1
`FOREIGN PATENT DOCUMENTS
`2039567 A * 8/1980
`2396178
`6/2004
`OTHER PUBLICATIONS
`Of?cial Action for Norwegian application No. 20030685.
`British Search Report issued for GB Patent Application No.
`06048508 on Jul. 10, 2006 (5 pages).
`* cited by examiner
`
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`

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`US. Patent
`
`Sep. 30, 2008
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`US 7,428,922 B2
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`US. Patent
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`Sep. 30, 2008
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`Sheet 2 0f 14
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`US 7,428,922 B2
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`Sep. 30, 2008
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`US. Patent
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`Sep. 30, 2008
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`US. Patent
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`Sep. 30, 2008
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`Sheet 6 0f 14
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`US 7,428,922 B2
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`US. Patent
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`Sep. 30, 2008
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`Sheet 7 0f 14
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`US 7,428,922 B2
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`US. Patent
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`Sep. 30, 2008
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`Sheet 8 0f 14
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`US 7,428,922 B2
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`US. Patent
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`Sep. 30, 2008
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`US. Patent
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`Sep. 30, 2008
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`Sheet 10 0f 14
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`US 7,428,922 B2
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`US. Patent
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`Sep. 30, 2008
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`Sheet 11 0f 14
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`US 7,428,922 B2
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`US. Patent
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`Sep. 30, 2008
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`US. Patent
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`Sep. 30, 2008
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`US 7,428,922 B2
`
`1
`VALVE AND POSITION CONTROL USING
`MAGNETORHEOLOGICAL FLUIDS
`
`TECHNICAL FIELD
`
`The present invention relates to the use of magnetorheo
`logical ?uids in doWnhole equipment to provide solid-state
`controls.
`
`BACKGROUND OF THE INVENTION
`
`Magnetorheological Fluids
`In the 1950s, it Was discovered that ?uids could be created
`Whose resistance to ?oW Were modi?able by subjecting them
`to a magnetic or electric ?eld. This Was disclosed in US. Pat.
`No. 2,661,596, Which is hereby incorporated by reference,
`Where the inventor also disclosed its use in a hydraulic device.
`Those ?uids that are responsive to an electrical ?eld are
`knoWn as electrorheological ?uids While those responsive to
`magnetic ?elds are magnetorheological. Of these tWo, mag
`netorheological ?uids have been the easier to Work With, as
`their electrical counterparts are susceptible to performance
`degrading contamination and require strong electric ?elds,
`Which necessitate complicated, expensive high-voltage
`poWer supplies and complex control systems. In contrast,
`both permanent magnets and electromagnets are inexpensive
`and easy to produce, While the magnetorheological ?uids are
`not as sensitive to contamination.
`Magnetorheological (MR) ?uids can be formed by com
`bining a loW viscosity ?uid, such as a type of oil, With mag
`netic particles to form a slurry. The original patent used par
`ticles of iron on the order of 0.1 to 5 microns, With the
`particles comprising 20% or more by volume of the ?uid.
`More recent Work in MR ?uids can be found, for instance, in
`US. Pat. No. 6,280,658. When a magnetic ?eld passes
`through the ?uid, the magnetic particles align With the ?eld,
`limiting movement of the liquid due to the arrangement of the
`iron particles. As the ?eld increases, the MR ?uid becomes
`increasingly solid, but When the ?eld is removed, the ?uid
`resumes its liquid state again. FIG. 1 is a graph of the ?oW rate
`of an exemplary MR ?uid through 0.4 inch inner diameter
`tubing versus the strength of the magnetic ?eld applied to the
`?uid. In each case, the ?oW rate goes to Zero as the ?eld
`increases. Magnetorheological ?uids have been used in such
`areas as dampers, locks, brakes, and abrasive ?nishing and
`polishing, With over 100 patents issued that utiliZe these ?u
`ids. MR ?uids can be obtained from the Lord Corporation of
`Cary, NC.
`DoWnhole Equipment
`Devices that are used in the development and production of
`hydrocarbon Wells have a number of constraints to Which they
`must adhere. They must be capable of handling the harsh
`environment to Which they are subjected, be controllable
`from the surface, and be siZed to ?t Within the small area of a
`borehole, yet the fact that they can be operating thousands of
`feet underground makes their reliability a high priority. Some
`of the problems encountered in drilling and production of
`hydrocarbons are as folloWs:
`1) It is imperative to reliably be able to trigger an event
`When desired, but not before. For instance, the ?ring of guns
`used to create openings through the casing into a formation
`must release enough energy to fracture through not only the
`casing, but also through damaged sections of the formation.
`Premature ?ring of the guns is both a safety issue (i.e., per
`sonnel can be injured) and an economic issue (equipment can
`be damaged, openings made into undesired strata must be
`repaired or bypassed).
`
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`2
`2) Many pieces of equipment used doWnhole have valves
`that must be opened and closed. In other equipment, the
`relationship betWeen tWo parts must be ?xed at some points in
`time, yet moveable at others, such in a travel joint, Which
`makes up for the movement of a drilling ship as it ?oats on the
`surface of the ocean. Traditional apparatus has relied various
`physical means to operate valves or release a part from a ?xed
`relationship. These can include rotating the drill string to
`release a J-fastener, relying on pressure, either Within the
`string or in the annulus, to rupture a valve or to apply the
`pressure necessary to move a part, and shear pins or similar
`devices. It is desirable to have more reliable means of oper
`ating this equipment more precisely. Additionally, the use of
`moving parts leads to rigorous designs that have redress costs
`and require rig time to trigger the valves. It Would be desirable
`to utiliZe solid-state valves to loWer costs, improve reliability,
`and decrease rig time for activation.
`3) It Would be desirable to provide a simple means for
`performing logical control steps, Without the use of moving
`parts.
`4) Devices such as packers traditionally use hard rubber
`parts to seal betWeen the doWnhole tubing and the casing or
`borehole. The rubber requires high pressures to set, and the
`in?atable packers that have been used Will not hold the large
`differential pressures of those using rubber packers. An alter
`native is desirable that Would not require large amount of
`force to set, but that Would handle large differential pres sures.
`Because of the variety of devices disclosed in the current
`application, speci?c examples of prior art devices are more
`fully discussed before the inventive alternative is disclosed.
`
`SUMMARY OF THE INVENTION
`
`Numerous devices that utiliZe magnetorheological ?uids
`are disclosed for use in oil and gas drilling and/ or production.
`With their ability to act as solid-state valves, MR ?uids can
`serve in areas such as 1) ?uid valving systems for locking and
`safety devices, 2) hydraulic logic systems, 3) position control
`and shock absorption, and 4) acting as a valve for other ?uids.
`In locking and safety devices, it is disclosed to use MR
`?uids as a hydraulic ?uid that controls a piston designed to
`initiate an event. The presence of a magnetic ?eld can prevent
`the piston from moving, acting as a safety lock for critical
`events. Examples are given for tubing conveyed perforation
`(TCP) guns, but are practical for many other locking appli
`cations.
`In hydraulic logic systems, it is disclosed to utiliZe MR
`?uid valves that have a logic value of “0” or “1” depending on
`Whether or not a magnetic ?eld is present. Systems can be
`designed to control doWnhole equipment by logical responses
`to sensor input. Valves can be tied together to create more
`complex logic
`It is further disclosed to control the position of one device
`relative to another device by MR systems. Movement of the
`devices relative to each other is tied to the movement of a
`piston through MR ?uid; by blocking the ?oW of the MR
`?uid, the relative positions of the pieces are ?xed. A magnetic
`?eld that is beloW that necessary to block ?oW can provide a
`time-delay or dampening effect.
`In packers, it is disclosed to utiliZe an MR ?uid in a packer,
`or other device to block the ?oW of other ?uids. By solidifying
`the MR ?uid, the seal can provide a strong barrier to the
`passage of other ?uids, While its ability to have a ?uid phase
`alloWs the MR ?uid to conform to the Walls of damaged
`Wellbores. Little force is require to set the packer, yet it can
`hold large differential pressures.
`
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`US 7,428,922 B2
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`3
`Devices utilizing MR ?uids Will have one or more of the
`following advantages: they are generally simple designs, ?t
`Well into existing systems, have feWer moving parts, and can
`be designed to fail (if electrical connections are lost) in either
`a valve open or valve closed position. The MR ?uid itself is
`relatively inexpensive, easily handled, non-toxic, and its vis
`cosity can be varied by simply changing the magnetic ?eld to
`Which it is subjected. Magnetorheological ?uid devices can
`offer simple, elegant solutions to a number of problems, as
`Will be further discussed.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The novel features believed characteristic of the invention
`are set forth in the appended claims. The invention itself,
`hoWever, as Well as a preferred mode of use, further objects
`and advantages thereof, Will best be understood by reference
`to the folloWing detailed description of an illustrative
`embodiment When read in conjunction With the accompany
`ing draWings, Wherein:
`FIG. 1 shoWs an exemplary graph of the ?oW rate of a
`magnetorheological ?uid versus the ?eld strength of mag
`netic ?eld applied to the ?uid.
`FIGS. 2AiE shoW various methods of constructing a mag
`netorheological valve assembly from magnets and/or electro
`magnets.
`FIGS. 3A and 3B shoW less desirable methods of interrupt
`ing the magnetic ?oW.
`FIG. 4 shoWs a conventional pressure-operated ?ring head
`for a perforation gun.
`FIG. 5 shoWs an exemplary ?ring head designed With an
`MR ?uid control
`FIGS. 6A and B shoW an alternate embodiment of ?ring
`head designed With an MR ?uid control before and during
`?ring
`FIGS. 7AiC shoW another example of a ?ring pin With a
`lock and/or time delay feature provided by MR ?uid.
`FIGS. 8AiC shoW a prior art circulating valve.
`FIG. 9A shoWs a three-Way valve such as can be used in a
`circulating valve, While FIGS. 9BiC demonstrates the valves
`in the tubing that can be controlled by the three-Way valve.
`FIGS. 10A*C shoW a prior art travel joint in a drill string,
`in both a locked and an unlocked position.
`FIG. 11 shoWs a partial cutaWay of a travel joint designed
`to utiliZe MR ?uid for position control.
`FIG. 12 shoWs a schematic of a number of doWnhole pieces
`of equipment, each tied to high-pressure and loW-pressure
`control lines and controlled through the use of magnetorheo
`logical valves.
`FIG. 13 shoWs a magnetorheological valve that Would
`re?ect the logical function of an exclusive “OR” applied to the
`tWo inputs.
`FIGS. 14A£ shoW a packer, utiliZing MR ?uid, Which can
`be set With little effort, but Which can Withstand a large
`pressure differential across the packer.
`
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`DETAILED DESCRIPTION OF THE DRAWINGS
`
`Embodiment of the disclosed system Will noW be discussed
`in further detail.
`
`60
`
`OvervieW of Valves Using Magnetorheological Fluid
`It is Well knoWn that if one side of an O-shapedpiece of iron
`is Wrapped With coils of an insulated conductor, an electro
`magnet can be formed. When a direct current is run through
`the coils, the iron underneath the coils is temporarily magne
`tiZed, With the polarity depending on the direction of current.
`
`65
`
`4
`The O-shaped piece of iron acts in a manner analogous to an
`electrical circuit to conduct the magnetic ?eld, or ?ux, around
`the magnetic circuit created, so that the entire piece of iron
`becomes an electromagnet. If, hoWever, a section of the mag
`netic circuit is removed, the magnetic ?eld cannot ?oW, just as
`in an electrical circuit. FIG. 2A shoWs a circuit similar to that
`described above, except that a passageWay 212 containing
`magnetorheological ?uid replaces one section of the
`O-shaped iron 200. When the direct current is passed (shoWn
`by darkened coils) through the coils 210, the iron in the MR
`?uid completes the magnetic circuit. The MR ?uid that is part
`of the circuit thickens or solidi?es (shoWn by the lines of force
`through the ?uid), depending on the strength of the magnetic
`?eld, While portions that are not subjected to the magnetic
`?eld remain liquid. In this embodiment, current is required to
`keep the valve closed, While a lack of current, shoWn in FIG.
`2B, maintains the valve in an open position, With the MR ?uid
`liquid (no lines of force).
`It is also possible to design a valve in Which a lack of
`current closes a valve, While a current opens the valve. FIG.
`2C shoWs an embodiment utiliZing a combination of a per
`manent magnet and an electromagnet. Rather than using an
`O-shapedpiece of iron, as in the previous example, an annular
`magnet 205 is used, With coils 210 Wrapped around one
`section of the magnet 205. Because of the constant magnetic
`?eld created by the permanent magnet (note the lines of
`force), MR ?uid in the passageWay 212 Will remain solidi?ed
`until the ?oW of magnetic force is disrupted. In FIG. 2D, a
`current is supplied to the electromagnet, giving it a polarity
`Which is opposite the polarity of the permanent magnet (note
`the opposing lines of force). The ?eld strength of the electro
`magnet can be adjusted so that the ?eld of the electromagnet
`cancels the ?eld of the permanent magnet and the magnetic
`?ux no longer ?oWs. This alloWs the MR ?uid to liquefy,
`opening the valve. FIG. 2E shoWs an alternate version of the
`valve of FIG. 2D. In this embodiment, it is more ef?cient to
`cancel the magnetic ?eld only in the Working gap (the con
`tainer 212 of MR ?uid) by redirecting the ?ux from the
`permanent magnet to a secondary, higher reluctance gap 220.
`If the coil 210 is off, most of the ?ux from the permanent
`magnet 205 ?oWs through the primary gap 212 and solidi?es
`the MR ?uid, effectively closing the valve. If the coil 210 is
`activated, the electromagnet’s ?ux cancels the ?ux from the
`permanent magnet at the primary gap 212, but doubles the
`?ux at the secondary gap 220. This effectively redirects the
`?ux to the secondary gap and opens the MR valve.
`FIG. 3A shoWs an alternate means of negating the effect of
`the magnet 205 on the MR ?uid in container 212. In this
`embodiment, the magnetic ?eld is shunted through a piece of
`steel 310 that provides a short circuit, alloWing the ?ux to ?oW
`Without going through the section containing the MR ?uid.
`FIG. 3B shoWs a method of interrupting the ?oW of ?ux by
`simply removing a piece 312 of the magnetic circuit, creating
`an open circuit. Both of these tWo embodiments require the
`movement of part of the circuit, to either add or remove a
`conductive piece. This could be done by applying ?uid pres
`sure, hydraulic pressure or mechanical force, but as the aim is
`to simplify the valve, these are much less preferred.
`Building further on the use of MR ?uids, the inventors of
`this application have identi?ed a number of speci?c areas in
`doWnhole drilling and production in Which magnetorheologi
`cal ?uid valves can be useful. These areas generally fall into
`four categories: ?uid valves for locking and safety devices,
`hydraulic control circuits, position control, and blocking the
`?oW of other ?uids and Will be discussed in these four general
`groups. Some applications do not fall easily into these group
`ings, but Will be discussed Where most appropriate.
`
`MEGCO Ex. 1022
`
`

`

`US 7,428,922 B2
`
`5
`Fluid Valves for Locking and Safety Devices
`Locking and safety devices are devices that have a one
`time operation, such that the system cannot be reestablished
`to its original condition. When dealing With the heavy equip
`ment and high pressures inherent in oil?eld Work, safety
`becomes a very important issue, and fail-safe mechanisms are
`mandatory. Locking mechanisms are used to ensure that a
`desired action, such as detonation of a perforation gun, does
`not take place prematurely. Using solid-state magnetorheo
`logical valves as described above, safety devices can be
`locked in an immovable state until a magnetic ?eld is
`removed using an electromagnet.
`In a ?rst application, We Will look at a control system for a
`?ring head in a tubing-conveyed perforation (TCP) gun that is
`operated using MR ?uids. First, let us look closer at the
`problems in this area. Conventionally, a perforating gun is
`actuated through a ?ring head that is responsive either to
`mechanical forces, such as the impact provided by dropping
`a detonating bar through the tubing, or to ?uid pressure, e. g.,
`through hydraulic lines. Additionally, some hybrid systems
`exist. Such ?ring heads, Where the piston is moved in
`response to hydraulic pressure, are believed to enhance the
`safety of the detonating system in that they are unlikely to
`detonate Without a speci?c source of substantial ?uid pres
`sure, Which Would not be expected outside the Wellbore.
`To provide added safety, especially for a mechanically
`actuated ?ring head, detonation interruption devices are also
`used. These devices are typically attached betWeen the ?ring
`head assembly and the perforating gun, and typically contain
`a eutectic alloy that melts at temperatures expected Within a
`Wellbore, but not at the surface, for example 1350 F. In its
`solid form, the eutectic material prevents the detonation sig
`nal from reaching the perforating gun, preventing accidental
`detonation at the surface. When the device is doWnhole, the
`increased heat Will melt the material and alloW detonation.
`HoWever, “normal” drilling conditions vary Widely. Detona
`tion interruption devices are very dif?cult to store in Saudi
`Arabia, for example, as surface temperatures can reach the
`material’s melting point. In areas like Alaska, the opposite
`problem occurs, as doWnhole temperatures may only reach
`70° F., preventing detonation When desired. These operations
`Would typically rely on a pressure-operated ?ring head.
`One example of a conventional pressure-operated ?ring
`head is seen in FIG. 4. A perforation gun is ?red When the
`?ring piston 410, poWered by pressure applied through pres
`sure port 418, contacts initiator 412. The pressure system is
`typically hydraulic, Which means that as the Well depth
`increases, the inherent hydraulic pressure in the pressure line
`becomes signi?cant. In order to prevent accidental ?rings,
`shear pins 414, held by shear sleeve 416, hold ?ring piston
`410 in place. To ?re the gun, the pressure through pressure
`ports 418 is increased until shear pins 414 shear off, alloWing
`?ring piston 410 to move and strike initiator 412. As Well
`depths increase, the number of shear pins necessary to hold
`the piston in place increases, With a concomitant rise in the
`pressure necessary to shear the pins. This increase can create
`additional problems depending on formation pressure and
`other completion equipment. The actuating pressures can
`become so high that either other equipment in the Well cannot
`Withstand it, or additional pressure Would result in the Well
`being completed in an over-balanced state as opposed to an
`under-balanced state. Thus, either safety factors are reduced
`or another means of ?ring must be found.
`FIG. 5 shoWs a ?ring head designed With an MR ?uid
`control. In this design, pressure port 518 is initially blocked
`by ?uid piston 520, so that no pressure can be applied to ?ring
`piston 510. As the ?ring gun is loWered into the borehole,
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`20
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`6
`pressure Would build up at pressure ports 518, tending to
`move ?uid piston 520 upWard and opening the pressure ports
`518 to the ?ring piston 510. HoWever, the movement of ?uid
`piston 520 is prevented by the presence of MR ?uid 524, held
`in place by solid MR ?uid 526 betWeen portions of magnetic
`assembly 522. Note that the magnetic assembly Will be
`designed With a permanent magnet, so that the un-poWered
`state of the valve is closed. The ?ring piston is not pressurized
`in this embodiment until the pressure ports are opened, so a
`single shear pin 514 is enough to hold ?ring piston 510 in
`place. To ?re the gun, an electromagnet is actuated to coun
`teract the magnetic ?eld of magnetic assembly 522. Solid MR
`?uid 526 is lique?ed, alloWing MR ?uid 524 to move into the
`?uid reservoir 528. This, in turn alloWs ?uid piston 520 to
`move, opening pres sure port 518, the pres sure then breaks the
`shear pin and alloWs ?ring piston 510 to strike initiator 512.
`Using an MR ?uid controlled safety lock on the TCP gun
`gives a much safer application. The safety is provided by a
`permanent magnet that can prevent movement, and only the
`intentional act of canceling the magnetic ?eld Will alloW the
`gun to ?re.
`An alternate embodiment of the ?ring head is seen in FIG.
`6A. In this embodiment, ?ring piston 610 is held aWay from
`initiator 612, not by shear pins, but by a collet restraint 616.
`When installed, the collet restraint 616 is held in an open
`position by a portion of the ?uid piston 620. In this open
`position, the outside diameter of collet restraint 616 is larger
`than the diameter of the ?ring piston 610 and cannot traverse
`the cylindrical surface 614 that contains the ?ring piston 610.
`Pressure communication ports 618 are in ?uid communica
`tion With the surface 630 of the ?uid piston 620, but are unable
`to move ?uid piston 620, because of the solid MR ?uid
`formed betWeen sections of magnetic assembly 622. FIG. 6B
`shoWs this same embodiment after the magnetic ?ux betWeen
`magnetic assemblies 622 have been cancelled, alloWing solid
`MR ?uid 626 to liquefy. This, in turn, alloWs the ?uid piston
`620 to be pushed aWay from the collet restraint 616, so that the
`collet restraint 616 can collapse inWard, alloWing the ?ring
`piston 610 to strike initiator 612.
`In either of the MR embodiments above, it Would be pos
`sible to add a time-delay feature to the ?ring of the guns by a
`simple means. Rather than entirely canceling the magnetic
`?eld in magnetic assembly 622, the ?eld can be partially
`cancelled, so that the MR ?uid in the gap is in a semi-solid
`state With a given ?oW rate. The chosen ?oW rate Would
`determine the time necessary for the pressure ports 618 to
`open and ?re the guns. Many other embodiments can also be
`designed to enable time delay.
`FIGS. 7AiC provide another example of a ?ring pin With a
`lock and/or time delay feature provided by MR ?uid. In the
`prior art, delayed ?ring could be achieved by a pyrotechnic
`delay element, Which is expensive, or a ?uid delay, Which
`requires a complex spring mechanism and expensive ori?ces
`that are susceptible to clogging and failing. MR ?uid control
`offers an inexpensive, simple alternative. In this example, a
`cylindrical piston 712 moves through a cylinder 714 contain
`ing MR ?uid 716. Fluid that is displaced by the piston travels
`up a tube 718 that goes through the center of the piston, to be
`collected in the region behind the piston. A magnetic assem
`bly 722 can produce a magnetic ?eld through the tube 718, to
`either sloW or stop the progress of the piston through the ?uid.
`When the magnetic ?eld is strong enough to solidify the MR
`?uid, it acts as a lock; When the magnetic ?eld is loWer, a
`semi-solid plug of MR ?uid 724 Will a delay the movement of
`the piston in a predictable manner. This can be used, for
`instance, to provide a fuse in Which the ?ring does not occur
`immediately after the event is triggered, but is delayed for a
`
`MEGCO Ex. 1022
`
`

`

`US 7,428,922 B2
`
`7
`given period of time. The sequence of draWings, FIGS. 7AiC,
`shows the piston as is descends. The time necessary for piston
`712 to descend until ?ring pin 730 contacts explosive initiator
`732 can be varied by varying the strength of the magnetic ?eld
`produced by assembly 722.
`The use of MR ?uid in implementing a TCP gun is only one
`example in Which a safety lock or time-delay feature can be
`implemented using an MR valve. A valve using MR ?uid can
`be used in any tool that relied on a failure mechanism to alloW
`movement, such as vent devices that rely on shear pins, set
`ting packers that rely on brass lugs, valves that rely on rupture
`discs, secondary release mechanisms that rely on shear pins
`or the shear of threads, live Well intervention tools that rely on
`collapsing springs or shear pins, sub-surface safety valves,
`bridge plugs, etc. Many others Will occur to one of ordinary
`skill in the art.
`
`Position Control
`Position control is de?ned in this context as a device that
`can repeatably have multiple positions that include restoring
`the device to its original position. To control the position of a
`part, the part is connected to a piston, Which moves through a
`cylinder ?lled With MR ?uid. Using a magnetic ?eld to
`solidify the MR ?uid in the cylinder prevents movement of
`both the piston and the part, While canceling the magnetic
`?eld alloWs movement. The speed of movement can also be
`controlled by the strength of the magnetic ?eld. TWo speci?c
`examples are a circulating valve and a travel joint.
`A circulating valve can be used to direct the ?oW of ?uids
`in Well tubing to different destinations, for instance, the valve
`can originally be closed, so that ?uids move doWn the tubing,
`later opened to alloW ?uids in the tubing to exit to the annulus,
`and ?nally closed again to halt doWnWard circulation. There
`are many different means of implementing a circulating
`valve, including valves that are operated by a Wireline tool, by
`annulus pres sure, or by internal tubing pressure. One example
`of a prior art circulating value is disclosed in Us. Pat. No.
`5,048,61 l,Which is brie?y discussed here. FIGS. 8AiC shoW
`this earlier circulating valve. Drill pipe 812 is connected to
`valve 810, and together form a continuous passageWay 814
`for ?uid ?oW (see also arroWs). PassageWay 814 has numer
`ous openings 842, Which are isolated from the annulus by
`sliding members 816 and 818. These sliding members 816
`and 818 are held in place by shear pins 820 and 822. In
`addition to openings 842, Which open to pressure area 862,
`openings 838 and 840 open respectively to pressure areas 848
`and 860.As Will be seen, these pressure areas are used to open
`and close valve 810.
`When circulation to the annulus is desired, a ball 880 is
`dropped into valve 810, Which seats at a loWer valve seat
`member 874, closing off the bore of the tubing and permitting
`pressure to rise. This rise in pressure is transmitted, through
`openings 842 (but not through openings 840, Which are sealed
`off) into pressure area 862, Where the pressure forces sliding
`member 818 to move in a doWnWard direction after shearing
`the shear pins 822, opening the valve, as seen in FIG. 8B. To
`stop circulation, shoWn in FIG. 8C, a larger diameter ball 884
`is pumped doWn the pipe to seat on upper valve seat member
`870, alloWing the pressure above ball 884 to rise. This pres
`sure is transmitted, through opening 838, to pressure area
`848, Where the pressure forces sliding member 816 to move
`doWnWard after shearing shear pins 820, once again closing