CA2046470A1

CA2046470A1 - Method and apparatus for actuating a downhole tool

Info

Publication number: CA2046470A1
Application number: CA002046470A
Authority: CA
Inventors: Dan Bangert; Richard Rubbo
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 1990-07-09
Filing date: 1991-07-08
Publication date: 1992-01-10
Also published as: EP0467573A3; BR9102864A; NO912676L; NO912676D0; EP0467573A2

Abstract

ABSTRACT OF THE DISCLOSURE
Method and apparatus for actuating one or more downhole well tools carried by a production or work string conduit having an imperforate wall and for blocking fluid communication between an activating fluid body and a second fluid source within said well across dynamic seals between actuating members of the well tool, by producing selective signals through the conduit wall detectable by a member to produce an activating signal for actuating the downhole well tool by a downhole energy source.

Description

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 I

20~647Q
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 ll il ,. I
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20~B470 1 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
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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 ~, l I~

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, , .;

20~647~ , !

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 30 ;1 i 1.

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, , ., .

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-1, 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.
,j il 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.

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.
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30 !¦

., 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 ~ -13-204~470 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 '; ~

'~0~647~J
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-30 !
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I!

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2046a~70 1 ,, I
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 !
i 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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Claims

1. An apparatus for completing a subterranean well, comprising:
a tubular conduit portion made up within a tubular conduit string of the type having an internal bore and having an imperforate wall extending from a point near the surface of the earth to a remote point downwardly within said well and in contact with a fluid source within said well;
signal generating means forming a part of said imperforate wall for selectively generating a signal in response to a predetermined condition detectable on said imperforate wall;
actuation means disposed exteriorly of said tubular conduit portion, said actuation means including an actuating member for performing at least one desired function;
means responsive to a predetermined change in said signal for activating said actuation means to actuate said actuating member for performing at least one desired function; and wherein said predetermined change of said signal is produced by a predetermined difference between annulus fluid pressure and conduit bore fluid pressure.

2. The apparatus of claim 1, wherein the actuation means includes a fluid pressure chamber located exteriorly of said tubular conduit and said actuating member includes a piston slidably and sealably mounted in said fluid pressure chamber for performing at least one desired function.

3. The apparatus of claim 2, further comprising:
packing means including a packer for sealing the annulus between said tubular conduit string and said well; and wherein said piston is slidably and sealably mounted in said fluid pressure chamber and operatively connected to said packing means to set said packer by axial movement of said piston.

4. An apparatus for completing a subterranean well having an imperforate conduit extending from the well surface downwardly into contact with well fluids, the apparatus comprising:
a tubular body made up within said imperforate conduit in series relation;
packing means surrounding said tubular body;
actuation means including an actuating member for moving said packing means into sealing relation between said body and the well bore;
latch means initially restraining said actuation means in an inoperative condition; and sensing means responsive to a predetermined change in strain in a wall portion of said tubular body for generating a signal to initiate release of said latching means, said predetermined change in strain in the wall portion of said tubular body being produced by a predetermined difference between annulus fluid pressure and conduit bore fluid pressure.

5. An apparatus for completing a subterranean well, comprising:
a tubular conduit portion extendable to a tubular conduit string having an internal bore and having an imperforate wall extending from a point near the surface of the earth to a remote point downwardly within said well and in contact with a fluid source within said well;
electrical signal generating means forming a part of said imperforate wall of said tubular conduit portion for selectively generating a plurality of distinctive electrical signals respectively responding to a plurality of distinctive conditions detectable on said wall;
actuation means disposed exteriorly of said bore of said conduit, said actuation means including an actuating member for performing at least one desired function;
means responsive to a predetermined change in the values of said electrical signals for activating said actuation means to actuate said actuating member for performing at least one desired function;
wherein said electrical signal generating means includes at least one strain gage mounted exteriorly on said imperforate wall and oriented generally transverse to the longitudinal axis of the tubular conduit string for detecting circumferential tension stress and circumferential compression stress in said wall perpendicular to the longitudinal axis of said tubular conduit string; and wherein said predetermined change in the values of said electrical signals are produced by a predetermined difference between annulus fluid pressure and conduit bore fluid pressure as detected by said strain gages.

6. The apparatus of claim 5, wherein the generally rectangular strain gages are mounted in pairs 180 degress apart at selected circumferential locations on said tubular conduit.

7. The apparatus of claim 6, wherein the electrical generating means also includes at least one strain gage mounted exteriorly on said imperforate wall and oriented generally parallel to the longitudinal axis of the tubular conduit string for detecting axial. stress in said wall.

8. The apparatus of claim 7, wherein said at least one strain gage is generally rectangular in configuration, having a first pair and a second pair of electrical connectors connected to the approximate mid-points of each side of the strain gage, said first pair of electrical connectors being adapted to detect changes in resistance due to changes in axial stresses in the tubular conduit and said second pair of electrical connectors being adapted to detect changes in resistance due to changes in circumferential stress in said tubular conduit.

9. A method of operating a downhole tool in a subterranean well having a tubular conduit string with an internal bore and with an imperforate wall extending from the surface to a fluid source within the well, the method comprising the steps of:
making up a tubular conduit portion within the tubular conduit string extending from a point near the surface of the earth to a remote point downwardly within said well and in contact with a fluid source within said well;

providing signal generating means as a part of said imperforate wall of said tubular conduit portion for selectively generating a signal in response to a predetermined condition detectable on said wall;
providing actuation means disposed exteriorly of said bore of said conduit, said actuation means including an actuating member for performing at least one desired function;
providing means responsive to a predetermined change in said signal for activating said actuation means to actuate said actuating member for performing at least one desired function; and wherein said predetermined change of said signal is produced by a predetermined difference between annulus fluid pressure and conduit bore fluid pressure.

10. The method of claim 9, wherein said predetermined condition detectable on said wall of said tubular portion is circumferential tension stress produced by increasing fluid pressure in the conduit bore above fluid pressure in the surrounding well annulus.

11. The method of claim 10, wherein said predetermined condition detectable on said wall of said tubular portion is circumferential compression stress produced by reducing the fluid pressure in the conduit bore relative to the fluid pressure in the well annulus.

12. The method of claim 10, further comprising the steps of:
securing a plurality of strain gages to a wall of said tubular conduit portion to selectively generate electrical signals in response to a change in the value of any one of axial tension, circumferential tension, or circumferential compression in said wall portion of said conduit, the changes in circumferential tension and circumferential compression being produced by increasing fluid pressure in the conduit bore above fluid pressure in the surrounding well annulus, and by reducing the fluid pressure in the eonduit bore relative to the fluid pressure in the well annulus, respectively.

13. The method of claim 12, wherein the string of tubular conduit extending from the well surface is held stationary while the tubing internal bore is pressurized from the surface.