Note: Descriptions are shown in the official language in which they were submitted.
20~6470
t BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION: The present invention
relates to subsurface well apparatus and ~ore particularly to
!! the remote operation of subterranean well tools.
2. SUMMARY OF THE PRIOR ART: Subsurface well tools
have been operated in the past by a wide variety of mechanisms.
,IManipulation of the tubing string, ~uch as pu6h and/or pull,
10 l¦ tubular rotation, and the like, i9 one of the more common
~! methods employed, but can be difficult to accurately accomplish
in deep or deviated wells. Other actuation means include u~e Of
! hydraulic/hydrostatic members~ pneumatic elements, as well as
Iradio and other surface and ~ub3urface-initiated electronic
icOmponents.
Typical of ~ubterranean well tools actuated by such
procedures include bridge plugs, packers, perforating guns,
tubing hangers, safety and other v~lve~, test tree~, and the
Illike, all of which are contemplated for use with the present
20 ll invention. Such tools require actuation procedures, such
Ias eetting at correct depth in the well and at a particular
,¦time during the completion operation, unsetting in response to
;ja given well condition or event, re-setting, opening, closing
!lor throttling flow paths, perforating casing, and the like.
25 l¦ In the normal operation of a well wherein the produc-
',tion tubing or work string i~ installed or being installed,
¦and the tools are to be ~ctivated by hydraulic means incorpor-
! atlng fluid and pressure within the production or work string,
'i it i8 very common to provide one or ~ore port~ in the wall of
30 ¦¦ the production tubing or work string, or a component in direct
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1 fluid com~unication therewith, to provide actuating fluid from
the bore of the production tubing to well tool~ to initiate the
desired operation, such a~ the setting of a packer. It ha~
been found that such openings provided in the wall of the
production tubing or work ~tring are highly undesirable because
such openings must be effectively sealed against any leakage of
any fluids subsequently carried through the tubing, such as the
I produced well fluids~ Seals that are employed in and between
, operating components of well tools, such as pistons and hou~ings
therefor, are ~ubject to deterioration, hence leakage, because
of the high temperature, high pressure environment in which
~uch seals are required to operate regardless of whether uch
seals are elasto~eric, metallic, or any other commonly used
8tructureR. ~his i8 particularly true of the seals employed on
actuating piston~ for packers, safety valves or similar downhole
tools wherein an act~ating fluid i8 appliea to one side of the
piston and the other side of the piston i~ exposed to well
fluids, at~ospheric pressure, or the like. Deterioration of
the ~eals on such actuating member expose such components to
undesirable leakage of either actuating fluid or production or
other fluids, depending on the relative pressureR, around the
piston, or other actuating component, thus initially creating a
microannulus therethrough. Such micro-annulus leak path could
be serious enough to ~ubject the well to a blow out.
25 i The utilization of a downhole energy source which can
be transformed into kinetic energy by the provision of a trig- ¦
'gering signal to operats a well tool is dlsclosed in U.S.
! Patent No. 3,233,674. In the illustrated device thereof,
'the downhole source of energy i8 an explosi~e charge which is
30 Idi8charged and the resulting gas i8 applied to a piston which
204647'~ 1
1 I functions to set a hanger in a well casing. The triggering
'~ignals for energizing the downhole circuitry for effecting
Ithe discharge of the explosive charge is produced by a pair
I o~ sonic frequency generators which are located at the surface
and which are transmitted downhole through well flulds or a tubing
,~tring, or can be packaged with a suitable power supply container
¦that is lowered into the well on wireline or cable.
One problem with apparatus con~tructed in accordance
with U.S. Patent No. 3,233,674, is that the acoustical signals
'employed for effecting the triggering of the downhole source of
energy must be coded in order to prevent inadvertent operation
jof the device by the static normally encountered in the trans-
~mission of acou~tic signals either through the well fluids or
through the body of a tubular conduit. The employment of coded
15 ll alternatlng signals necessarily complicates the electronic
" pickup circuitry which must be designed go a~ to distinguish
;Ibetwee~n static signals and the proper coded ~ignal.
¦~,"IJ, . '~ ~ U-S- Patent No. 4,896,722 discloses another approach
41tO energization of a downhole source of energy. In the appar-
20 'latus illustrated in this patent, the hydrostatic pressure
! f well fluids in the well annulus acts on a floating piston
to provide the source of downhole energy. Such energy is
~employed to effect the opening and closing of a test valve which
l i3 normally utilized in the lower end of a string of drill stem
25 ¦ testing tool~. The hydrostatically pressuri~ed oil acts on one
, side of a piston which is opposed on its opposite side by air
~at atmospheric or other low pressure. The piston is prevented
Ifrom movement by a spring until a predetermined hydrostatic
i annulus presqure is obtained. A pair of solenoid controlled
3o ! valve~ control~ the hydrostatic presYure acting on the floating
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1 piston. The two ~olenoid control valve~ are in turn controlled
by a microprocessor which operate~ in response to a pre~sure
tran~ducer which i8 exposed to annulu~ pressure and provide~
lan electrical ~ignal output indicative thereof. Again, however,
;~the signals applied to the pres~ure transducer are in the
nature of a ~eries of low level pre~sure pulses, each having
! a specified duration. Such pulses are applied at the well
! surface to the fluids ~tanding in the well annulus. Thu8,
lthe detection circuitry which picks up the Rignal~ is complicated
¦because it has to be designed to respond to only a specific
series of low level pres~ure pulses.
I The prior art has not providsd an actuating system for
'la downhole well tool which does not require ports in the pro-
duction tu~ing or work string or component in fluid communication
therewith, and which may be reliably controlled from the ~urface
through the utilization of control forces through the wall of
! the production tubing or work string to produce an activating
3ignal for actuating the downhole well tool by a downhole
energy ~ource and to block fluid communication bet~een an
actuating fluid body and a second fluid source within said well
across dynamic seals between actuating member~ of the well tool.
SUMMARY OF T~ INVENTION
..
l The method and apparatu~ of thi~ invention may be
25 1 employed for the actuation of any one or more downhole tool~,
such as packers, safety valvea, te~ting valves, perforating
~ gune, and the like. ~he apparatus employed in the invention
j contemplates a production tubing or work string portion extend-
¦able to a tubular conduit string extending from the earth
j¦~urface down into contact with the well fluid~ existing in the
well. The wall of ~uch production tubing i6 imperforate
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1 'I throughout itR entire length and to ~nd through tlle actuating
! members of the well tool or tools to be actuated. The appar-
atus and method block fluid communication between an activating
,j fluid body and a ~econd fluid ~ource within the well acro~
lldynamic seals between the actuating memberR of the well tool
! during actuation thereof.
¦ The apparatus and method of the present invention also
jlcontemplate incorporation of a signal generating means which
l¦forms a part of the wall of the tubular conduit portion for
¦8electively generating a signal in response tG a predetermined
condition which is detectable on the wall of the conduit qtring
or portion. Actuation means are di~posed exteriorly of the
bore of the production conduit and include an actuating member
l for performing at least one desired function. An activating
body is in direct or indirect communication with the actuating
member. Movement prevention ~2ans selectively resist movement
! of the actuating member. Preferably, releasing means are
responsive to the signal generating means for releasing the
l movement prevention means from the actuating member for perform-
20 ¦ ance of the desired function or functions, and the apparatus~hue prevents direct fluid communication between the activating
fluid and the second fluid source acros~ the seals.
¦ A packsr which may be incorporated with this invention
¦may be mounted in surrounding relationship to the production
tubing or work string and actuated by the downhole apparatus of
this invention to ealingly ~ngaqe the bore wall of the well
ca~ing.
l The ~ignaling generating means preferably co~prise a
i strain gauge forming a part of the imperforate wall of the
3o i production tubing, but may al~o be a piezo electric crystal,
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1 1 light beam, sonic vibratory component, or any other non-msgnetic
transducer or electronically activated element which generates
a signal whlch is detectable as hereinafter de~cribe~ and
¦contemplated. The strain gauge, or other element, i6 mounted
l80 as to detect all forms of stress or other phy~ical phenomena
l(hence, strain) detectable on the wall p~rtion.
j~ In the case of a strain gauge, a first ~ignal may
,¦be produced in response to a preselected circumferential tensile
,Istress, a different signal in respon~e to a preselected cir-
10 ll cumferential compressive ~tress, or other signal~ respectively'¦corresponding to the existence of predetermined strain in the
wall portion of the production tubing or work ~tring portion
to which the strain gauge is affixed.
l During the initial run-in of a production tubing and
15 , a packer, it i8 obviously difficult to apply any lasting change
j! in circumferential tension or other stress, in the wal~ of the
Iproduction conduit portion to which the strain gauge iq affixed.
! However, variation of the ~en~ed pressure at the location of the
1! strain gauge to a level ~ub3tantially different than an initial
! pre58ure within the tubular conduit will reYult in a significant
change in the strain, with the corresponding generation of a
~igniicant change in the resistance characteristics between
¦circumferentially spaced contact points of the strain gauge~
llwill be produced, resulting in a significant change in reqictance
25 li between the sa~e circumferentially spaced contact points of the
l ~train gauge.
I On one embodiment of the invention, such changes in
! average value of the re~istance of the ~train gauge are detected
i by a conventional electronic hookup to a microprocessor (shown
30 ¦ only ~chematically in the drawing~ and not forming a part of
1.
` ^ 2046d~7~ (
1 the inventive concept per se). The average value change~ are
amplified to a level sufficient to effect the activation of a
stored or other ener~y actua~ing mechanism which may take a
i variety of for~s, ~uch a~ an explosive charge which is fired to
Igenerate a hig~ pressure gas, a ~pring, or a motor, which is
then employed to shift a piston or other mechanism, to effect
!~ the actuation of a well tool, for example, a packer.
The control signal could also be employed to operate
one or more solenoid valves to derive energy from the hydrostatic
annulus pressure to effect the opening or cloqing of a testing
valve or safety valve.
Lastly, and in accordance with this invention, the
~ control signal can be employed to function as a latch release
! means for a downhole tool actuating piston diRposed in a chamber
formed exteriorly of the production conduit and containing
pressurized gas either generated in-situ, or stored, or explos-
ively created, urging the piston or other activating mechanis~
in a tool operatin~ direction. So long as the latch mechanism
is engaged with the piston, or the like, the tool is not oper-
able, but the control slgnal is applied to a solenoid to releasethe latch, thus releasing the piston for movement to effect the
actuation of the tool.
. A8 will be later deqcribed, such tool may conveniently
,,comprise a packer which i8 set by the release of the latch in
~response to a predetermined change in strain in that portion of
the production conduit on which the strain gauge is mounted.
When the packer is set, other signals may be generated
for various useful purposes. The setting of the packer will,
! for example, effect a substantial reduction in the axial
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1 i!tensile stress existing in the conduit above the packer. If the
train gauge is so located, it will generate a Hignificant
in-citu signal which can be ent to the ~urface by an acoustic
llor radio frequency transmitter to inform the operator that the
5 1I packer or other downhole tool has indeed been set, or activated.
, Alternatively, and particularly when the production
iltubing or work strinq i~ being initially in~talled, the second
" slgnal generated by the strain gauge upon or at any time sub-
llsequent to the setting of the packer, can be utilized to effe t
10 ~;the firing of a perforating gun or other activation of a
l¦second or auxiliary well tool. However, it i8 so~etime~
jidesirable that the perforating gun be fired when the pre~sure
conditions in the production zone below the packer are in a
~Ro-called "underbalanced" condition, where the fluid pre6sure
within the production conduit is significantly less than the
annulus fluid prassure. Thi8 reduction in production tubing
pressure ~ay be conventionally accomplished by running the
production tubing or work string into the well dry by having
Ija closed valve at its lower end, or by swabbing any fluids
20 Ijexisting in the production tubing or work string from the well
~iafter the packer is set. This procedure has many variable~ and
,Isuch procedure and variables are well known to tho~e ~killed in
ithe art. In either event, the resulting change in circumferen-
~¦tial compressive stres~ will result in the ~train gauge producing
25 '¦a distinctive ~ignal which ~ay be employed to effect the firing
¦of the perforating gun.
After the firing of the perforating gun, it i~ com~on
i! to kill the well, unset the packer, retrieve the work string
i~and run into the well a permanent completion hook-up, including,
30 ~for ex~r~ple, ~ ~fety v~lve, ~ packer, ~ production rcreen,
,
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20~6~70
1 ` or ported sub, and the like. The production string is posi-
I tioned in the well 90 as to place the screen, or ported sub,
1, to lie adjacent the newly formed perforations in the casing,
I thus permitting production fluid to flow through the screen
1 or ported sub and into the production tubing.
i If a test valve i8 incorpora~ed in the lower portion
of the production tubing, it can be maintained in a closed
`, position by a spring or other means, and conventional instru-
I mentation disposed within the production tubing can effect a
10 'I mea urement of the formation pressure. An increase in fluid
pressure within the production tubing over the annuluq fluid
presqure will re~ult in a circumferential compre~sive stress
in the strain gauge accompanied by a significant change in the
llresistance of the strain gauge in the circumferential direc-
15 jtion. This signal can be employed to efect the opening of thetesting valve or safety valve as the ca~e may be, by a solenoid
winding disposed in surrounding relation to the production
tubing. Such solenoid operated testing valves and/or safety
! valve~ are well known in the art.
20 I The electrical energy for operating the various
solenoids heretofore referred to i8 preferably supplied by a
jdownhole battery pack which i~ disposed in the annulus sur-
rounding the production tubing string.
I Those skilled in the art will recognize that the
25 j actuation of one or a plurality of downhole well tools by do~n-
hole energy sources in re~ponse to a pre-determined condition
detectable on a portion of the wall of an i~perforate produc-
tion or work tubing string portion provides an unusually
lecono~ical, yet highly reliable system for effecting the remote
operation of downhole well tools and for blocking fluid com~un-
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20~647~ 1
1 ¦ ication between an activating fluid body and a ~econd fluid
,source withln the well across dynamic gealg between actuating
¦me~bers of a well tool during the actuation procedure.
Il Further advantages of the invention will be readily
¦apparent to those skilled in the art from the following detailed
description, taken in conjunction with the annexed sheet~ of
drawings.
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10 1¦ RIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 i~ a schematic, vertical se~tional view of
a well showing a tubing string incorporating a packer, a
¦safety valve, and a perforating gun positioned in the well
sub3equent to setting of the packer in response to ~ignals
¦generated by a strain gauge forming a portion of the wall of
Ithe production conduit.
'¦ Figs. 2A, 2B and 2C collectively repreqent an
¦enlarged scale, vertical sectional view of the unset packer and
¦Ipacker actuating ~echanism, including a schematic showing of
20 ¦ the strain gauge and microprocessor employed for setting the
packer and actuating other well tools.
l Figs. 3A, 3B and 3C respectively correspond to
I Figs. 2A, 2B and 2C but show the position of the packer and
its actuating mechanism after the setting of the packer ha~
1 been accomplished.
25 1
Figs. 4A and 4B schematically illustrate alternative
connections to ~train gauges to detect changes in axial and/or
l circumferential ~tres~es in a production conduit.
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20~6470
1 DESCRIPTION OF THE PREFERRED EMBOI)IMENTS
, Now, with reference to the drawings, and, in part-
j icular, Fig. 1, there is shown schematically at the top thereof
a wellhead 11, conventional in nature, securing a production
conduit 12 extending from the lowermost facial -~ide of the well-
head 11 into a subterranean well 10. The production conduit 12
,I may be production tubing, or a tubular work ~tring, conventional
in nature, and well known to those skilled in the art.
The production conduit 12 is shown a~ carrying a safety
valve 13, which may take the form of a ball, flapper, or other ;
valve con truction known to those skilled in the art. A packer
14 i8 schematically illu~trated as being disposed on the pro-
duction conduit 12 below the safety valve 13, with the conduitv
12 extending in the well 10 and within ca~ing 15.
j Actuation controls 16, depicted in more detail in Figs.
2B, 2C, 3B, and 3C, are disposed on the well conduit 12 below
¦the packer 14.
¦ A~ shown, a well production ~creen 17 is shown on
,ithe conduit 12 above a perforating gun 18. It will be appre-
ciated by tho~e skilled in the art that, in lieu of a screen
17, ~ simple ported qub may be utilized for introduction of
¦production fluid~ fro~ the production zone PZ of the well 10
into the annular area between the casing 15 and production
conduit 12, thence interiorly of the conduit 12 to the top
¦of the wellhead 11.
The perforating gun 18 is shown as a tubing-conveyed
l¦perforating gun which i5 well known to those in well completion
! I technology.
.
30 !¦
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20q6470
1 Now, with reference to Figs. 2A, 2n, and 2C, the
~apparatu~ of the present invention is ghown di~posed within
the casing 15 with ~he packer 14 being po~itioned in unset
mode The production conduit 12 extend~ to a conduit member,
or body 142, having thread~ 141 at its uppermo~t end for Becure
ment to companion threads in the lowermost 6ection of the pro-
duction conduit 12 thereabove. I
A securing ring 144 i~ carried around the exterior
of the body 142 for containment of the uppermost end of a series
0 ! of 81ip members 145 having contoured teeth 146 circu~ferentially
subccribed exteriorly therearound for embedding and anchoring
engagement of the packer 14 relative to the casing 15 when the
;,tool i8 shown in the set po~ition, as in Figs. 3A, 3B, and 3C.
The 81ip8 145 have a lower facing beveled slip
Iramp 150 for companion interface with a ramp 149 carried at the
~uppermost end of an upper cone member 148 being carried exter-
iorly around a support member 146, with the upper cone 148
,secured to the ~upport 146 by mean3 of shear pin ~embers 147.
~Thus, the slip~ are ~ecured in retracted po~ition relative to
the cone 148, prior to setting actuation.
Below the cone 148 i8 a serie~ of non-extrusion ~eal
membern whi~h ~ay comprise a combination of metallic and ela~-
;tomeric seal a~emblies, the seal ~y~tem 151 being carried
exteriorly around the cone 148. The sy~em 151 is affixed
25 ,around the exterior of the body 142 and at the uppermost end
of a conventional elastomeric seal element 152 having an upper
inward lip 152a extending interiorly of the seal ~y~tem 151.
At the lowermost ~nd of the seal element 152 i~ a
lower lip 152b of ~imilar construction ~s the lip 152a. Ex-
30 It~riorly of the lip 152b iq a second, or lower, non-extrusion
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204~470
1 I ~eal ~ystem 151 which, in turn, 1~ carried around it~ lowermo~t
end ~n the uppermogt beveled face of the lower cone element 153
~Iwhich is shear ~inned at pin 154 to the body 142.
I~ A lower ramp lSS is carried exteriorly around the
ilcone 153 and contoured interiorly at it~ lowermost tip for
~Icompanion interengagemen~ with a similarly profiled 81ip ramp
,il156 around the uppermost interior surface of the slip element -
157. T~he lower slip 157 has teeth 158 which are ~imilar in
llconstruction to the teeth 146 on the uppermost slip rings or
,elements 145 for interengagement to anchor the device relative-
;to the casing member 15 when the tool is in the set position,
lag ghown in Fig. 3A.
Below the lowermost slip ring 157 i8 a body lock ring
l¦160 which is housea exteriorly of the body 142 and interior of
15 l¦ an outer ring 162 having ratchet threads 159 thereon. The
Ipurpose of the body lock ring 160 and ratchet threads 159 is
Ijto lock the ~etting energy resulting from the ~etting actuation
jof the packer 14 into the upper and lower slip~ 145, 157, and
'¦to thus assure sealing integrity of the ~eal element 152 rela-
20 1! tive to the casing 15. The ratchet teeth 159 are, of course,one way acting, but could be provided in a configuration which
¦would permit resetting of the device subsequent to unsetting.
¦ At the lowermost end of the body element 142 is a
¦~series of threads 143 for securing the body 142 to the tubular
25 ~¦member 19 extending to the actuation controls 16, ~hown in Figs.
¦2B and 2C.
,i Now referring to Figs. 2B and 2C, the actuating sleeve
¦¦162 extends to the outer ring portion 161 at its uppermo~t end
l! and is secured at threads 163 to a pi~ton mandrel 164. The
30 . pi-ton rlendre1 164 haG a GerieG of elaGto~eric or etallic
1, i
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1 !1 8eal member~ 166 to prevent fluid communication between the
Riston mandrel 164 and the member 19.
'I At the lowermost end of the piston mandrel 164 is
ian enlarged piston head 165 having ~eal members 165a thereon.
i~The piston ~andrel 164 is ~ecured at threadq 169 to a lock
~leeve 191 which has at its lowermo~t end (Fig. 2C) a locking
jdog ~ecured in place within a groove 178 profiled in the member
19 to prevent relative movement between the lock sleeve 191
l¦and the member 19 prior to actuation, as di~cussed below.
10 ji Above the piqton head 165 is an atmospheric chamber
68 which extends between the eal members 167 and 165a.
Below the seal member 165a on the piston head 165 i~
a nitrogen chamber 171. Nitrogen is emplaced in the chamber
171 through the ~iller paC~sage 172 which iB capped at 173 sub-
j~equent to the filling procedure which i9 performed prior to
introduction of the apparatus into the well.
A cylinder housing 170 is ~ecured at threads at its
uppermost end to the piston mandrel 164 and at threadY 173 to
lan actuator hou~ing 174 there below. The nitrogen chamber 171
20 ,lis defined between the seals 165a in the piston head 165 and
a series of similar seals 175 in the cylinder housing 170.
! Housed within the cylinder housing 170 at its upper-
,l~08t end and the actuator housing i~ a master control spring 176
!¦carried exteriorly of a ~pring housing 179.
25 I Below the lowermost end of the spring housing 179 is
~,a non-~agnetic ~olenoid member 180, of conventional construction, ¦
! which is 6ecured above a ferro-magnetic core member 181. The
¦solenoid member 180 i~ in co~munication electronically with the
l~train gauge 183 through a microprocessor 185 by means of
circuit lines 182, 183. The strain ga~ge 183 iB secured to the
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2046~71~
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1 outer wall of the member 19, such that the given condition
on the wall of the conduit member 19 i8 sensed by the gauge la3.
Below the strain gauge 183 and communicating therewlth
jby electric lines 182a i8 a microproces~or 185 which may be
~lpre-programmed prior to introduction of the apparatus into the
well to detect and generate instructions relative to the solen-
oid member 180 and the strain gauge 183 in known fa3hion.
A battery 187 provides electrical energy through lines
186 to the microproce~sor 185.
The cylindrical housing 170 is ~ecured at threads
188 to a lower sub 189 which, in turn, i8 secured by threads
,~190 to another 3hort section of production tubing, or the like,
~or may be 8i~ply bull-plugged and thus defining the lowermost
end of`the production conduit 12. Alternatively, an auxiliary
5 ;i! tool may be di~posed below the actuation controls 16, such a~
the perforating gun 18.
The downhole signal generating means embodying this
'~invention comprises a strain gauge 400 applied to the wall of
,Ithe production conduit which will change its resistance in
2~ response to significant changes in the stresses existing in
the conduit wall to which it is attached. Strain gauge 400
may be of rectangular configuration as shown in Fig. 4A with
Ijconnnectors 400a, 400b, 400c and 400d respectively connected
;¦to the mid points of each side of the strain gauge 400. Thus
25 ! connector~ 400a and 400c will detect changes in resi~tance due
llto changes in axial tre~s in the conduit. Connectors 400b
,! and 400c will detect changes in resistance due to changes
in circum~erential stress in the conduit. Connectors 400a,
¦400b, 400c and 400d thus provide signal inputs to the micro-
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2046a~70 1
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1 il proce ~or 410 which wlll generate an activating voltage for
operating a downhole tool~ ~uch as the packer 14.
I! The ~econd strain gauge 402 is circumferentially
¦l~ecured to the conduit and has connectors 400b and 400d
l~secured to its opposite ends to indicate axial stre~ses in the
conduit.
Il OPERATION
I
A~ set forth above, the apparatus of the present
invention i8 run into the well interior of the casing 15
¦and below the wellhead 11, with the production conduit 12
icarrying well tools, such as the safety valve 13, packer 14,
~ creen 17 and perforating gun 18. The actuation controls 16
l are ~hown in Fig. 1 positioned below the packer 14 on the pro-
15 ' duction conduit 12. However, it will be appreciated that such! a control 16 may be po~itioned either above or below the packer
14, or other well tool on the production conduit 12.
When it is desirea to set the well packer 14, the
! production conduit 12 may either be set down, picked up, or
20 ' rotated, either clockwise or counterclockwise. The micro-
processor 185 has been pre-programmed to detect a predetermined
, sequence of strain caused thereby, which is, in turn, detected by
! the strain gauge 183. The battesy 187 delivers energy power
l through line 186 to the microprocessor 185 which, in turn,
¦¦governs the strain gauge 183.
A~ the strain gauge 183 detects the stresses defined
¦through the production conduit, a signal iB 6ent through line 182
l to the ~agnetic solenoid member 180 which, in turn, actuateq a
i trigger to shift the spring housing 179 ~uch that the locking dog
30 ~ 177 ~ay be removed froo the groove 178 of the lock sleeYe 191
which, in turn, permit~ the control spring 176 to act a~ a boo~ter
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204~470 1
1 'up~n the piston head 165. Accordingly, the energy in the nitroqen
chamber 171 moves the pi~ton head 165 again~t the Atmospheric
! chamber 168 to urge the piston mandrel 164 upwardly and move
llthe sleeve 162 upwardly such that the lower ~lip 157 moves on
~Ithe ramp 155 to urga the teeth 158 of the lower slip 157 out
into biting engagement with the internal wall of the casing 15.
'¦Contemporaneously with such movement, the energy transmitted
~Ithrough the actuation of the piston head 165 i8 transmitted
Isuch that the upper cone 148 moves relative to the upper slips
10 ,l145 to permit the teeth 146 of the upper slip 145 to engage the
! casing 15. Correspondingly, the seal element 152 i8 compressed
'and the Yeals 151, 152 move into sealing engagement with the
,¦interior wall of the casing 15. Contemporaneously, the lock ring
1160 ratchet~ relative to the thread~ 159 and the outer ring 161
'to secure the packer actuation in place,
It will be appreciated that the actuation controls 16
have a member 19 thereon which i~ not ported, such that the
Idynamic ~eals 165a, 166 do not come into fluid communication with
.¦the fluid either in the atmospheric chamber 168 or in the interior
20 ¦f the production conduit 12, nor do ~uch ~eals contact or
communicate directly with fluid in the annulus between the casing
¦15 and the production conduit 12.
~¦ Although the invention ha~ been described in terms of
,Ispecified embodiment~ which are set forth in detail, it should
25 ! be under8tood that thiq ie by illu5tration only and that the
.linvention i8 not necessarily limited thereto, since alternative
'lembodiments and operating techniques will become apparent to
¦those skilled in the art in view of the disclosure~ According-
llly, modification~ are contemplated which can be made without
30 1! departing from the 8pirit of the descri~ed invention.
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