US2942665A - Drillable packer - Google Patents

Description

June 28, 1960 Filed July 2, 1956 R. C. DAVlS ETAL DRILLABLE PACKER 3 Sheets-Sheet 1 INV'ENTORS Ray C Dav/5 Poland 0. (0X Jahn J. Lane ATTORNEYS June 28, 1960 R. c. DAVIS EI'AL 2,942,655

DRILLABLE PACKER Filed July 2, 1956 3 Sheets-Sheet 3 as :i 52

4 29 m INVENTORS Ao/cma 0. Cox

John J. lane United States Patent DRILLABLE PACKER Roy C. Davis, Roland 0. Cox and John J. Lane, Dallas, Tex., assignors, by mesne assignments, to The Guiberson Corporation, Dallas, Tex., a corporation of Texas Filed July 2, 1956, Ser. No. 595,455

3 Claims. (Cl. 166-124) This invention is concerned with a well packer which is employed for closing off a well pipe or for sealing the annular space between a well casing and a tubing or other pipe extending into the casing, for producing .oil or gas from a strata below the packer, or for the purpose of carrying out various well operations, such as cementing, acidizing, or otherwise treating the producing formation or formations of the well.

This invention is particularly concerned with improvements in that type of well packer known as a drillable packer wherein all parts are made of drillable material so that it can be drilled up by the drill bit for removal, but it will be understood that the improvements described and claimed can be employed in any well packer of the type herein described, whether it be drillable or not.

Well packers of the type designed to be run and set in the casing are usually provided with a sleeve of elastic material, such as natural or synthetic rubber, which is slidably mounted on a tubular support or mandrel. Segmented, toothed slips are provided at each end of the packer sleeve which co-act with conical expander heads to expand the slips into engagement with the casing to form an anchor, and to compress and expand the packer to seal the annulus. The conical expander heads are attached to, or are in contact with, the rubber sleeve, and as the lower slips are moved upwardly along the casing wall they push the lower expander head upwardly against the packer sleeve, causing the resilient packer sleeve to be shortened and expanded radially into sealing engagement with the casing wall.

In prior packers of this type the force for expanding the packer sleeve has been applied by upward pull applied to the lower slips, which are carried on a base shoulder attached to the running tool, and such force was indirectly applied to the packer sleeve through the expander head. Such arrangement resulted in a great loss of force by reason of the fact that the greater amount of the force applied was dissipated in dragging the toothed slips along the wall of the casing a sufiicient distance to move the lower expander head upwardly enough to adequately expand the packer sleeve into sealing engagement with the casing. It has been estimated that at least 60% of the force applied by upward pull was dissipated in dragging the slips along the casing wall. This necessitated increased upward movement of the tubing in order to set the packer, which is particularly disadvantageous in deep wells Where the amount of upward movement of the tubing is limited by reason of the stretch of the tubing and in many instances resulted in an insufliciently expanded packer. Such increased pull resulted in added strain on the derrick, pipe and surface equipment, and the operator could never be certain that the packer was sufliciently expanded to form a proper seal.

Another defect in such prior packer devices was that the segmented slips did not move upwardly into engagement with the casing uniformly so that they were not evenly spaced and in peripheral alignment under the packer, causing the packer to be off center, resulting in uneven distribution of the rubber material of the packer in the annulus when expanded, and a poor seal.

Still another problem with such prior packers was that the lower expander head and slips were attached to the mandrel, and prevented from moving upwardly thereon, solely by shear pins, with no positive means to prevent the expander head and slips from being disengaged from the mandrel and allowed to move upwardly while being run, often resulting in premature setting of the packer.

In such prior packers the running tool, is threadedly engaged with the packer mandrel by left hand threads so that after the packer is set the running tool can be disengaged by right hand rotation of the tubing. Heretofore no positive means has been provided for preventing the rotation of the mandrel while the running tool is being unthreaded therefrom.

This invention is intended to overcome the abovementioned problems and others.

It is, therefore, a primary object of this invention to provide a well packer wherein substantially all -of the force applied by upward pull on the running tool .is applied directly to the lower expander head and therethrough to the packer sleeve.

Another important object is to provide means ina well packer for uniformly moving the lower slips into engagement with the casing, whereby they are in peripheral alignment under the packer. I i

A further object of this invention is to provide positive means in a well packer for preventing the lower expander head from moving upwardly to prematurely set the packer while the packer is being run.

A still further object is to provide means in a well packer to positively hold the packer mandrel against rotation while the running tool is being rotated free of the mandrel after the packer has been set.

Still another object is to provide positive means in a. well packer to prevent upward movement of the upper expander head of the packer assembly, while the packer is being run, to prevent premature setting of theupper slips.

Another object is to provide a shoulder on the packet mandrel which moves upwardly in the packer sleeve, when expanded, to form a recess between the shoulder and the lower expander head, in which the rubber of the packer sleeve may flow when the packer is expanded, to thereby transfer force, applied from above, directly to the packer, after it is set, to increase the sealing effect thereof.

A still further object is to provide a packer assembly wherein the upper slips are set before the lower slips to provide a firm anchor for setting the lowerslipsand expanding the packer sleeve.

Other and further objects of this invention will become apparent upon reading the following detailed specification, and by referring to the drawings annexed hereto, and made a part hereof.

A preferred embodiment of the invention is shown in the attached drawings in which,

Figures I and II are a partially sectionalized, eleva' tional view of a well packer assembly incorporating the improvements constituting the invention, showing the packer assembly and attached to the running tool as they would be assembled for lowering into the casing on a tubing string.

Figure III is a partially sectionalized, elevational view of the packer assembly after the running tool has been disengaged from the anchor cage and drawn upwardly to set the upper slips.

Figure IV is a partially sectionalized, elevational view of the packer assembly after the running tool has been further drawn upwardly to shear the upper and lower expander heads fiom the mandrel and the lower slips from thelo'wer expander head to permit the spring urged pins underneath the lower slips tomove said' slips up wardly intoengagement with the casing.

V .Figure V is a partially sectionalized, elevational view packersleeve has been expanded intoengagement with the casin V Figure V1 is a partially sectionahzed, elevationalview tfthe packer assembly after the packer sleeve has been fully expanded into sealing engagement with the wall of meaning. i

' a Figure VII isa sectionalized, elevational view of the packer assemblyafter the running tool has been disengaged therefrom and withdrawn.

thebody 32. I The longitudinal movement of therings p Figure VIII is a partially sectionaliz ed,,elevational view 7 of the packer assembly after the running too] has been reinserted subsequent to attaching a' tailpipe, crossover V apparatus or other well producing or treating apparatus.

ln. the drawings numeral references are employed to designate the various parts, and like numerals indicate like pants throughoutthe various figures of the drawings.

flackers of the typeshown herein are customarily lowered into the well casing, .disengageably'attached to a tool which issuspended to a string of pipe, extending from the earths surface.

Figures I and II show the packer assembly, attached to the running tool, as it would be assembled for lowering intothe casing. The packer is relaxed and run' with clearance, except for the drag of the spring urgedfriction pads 34 on theanchor cage 31.

Thesub 10 is interiorly threaded at its. upper end, as

indicated at 11,10 permit the threaded engagement of the sub with a tubing string (not shown), extending'from the earths surface.v upper tubular member 12 'is threadedlylengaged to thesub 16 by righthand'corn p'anion threads 13. Theadaptor coupling 14 is threadedly connected to thetubular member 12 by righthand companion threads 15 and to thepacking tube 16 by fighthand companion threads 17.

An annular outwardly extendingflange 18 is formed on the upper end of theadaptor coupling 14, and a resilient sealing ring 19 is disposed about theflange 18 to jform a seal between the inner surface of theupper ex- 3 pander head '49 a d the fla ge i A seal retainingabuttment collar 20 is afiixed' about 7 the packing tube'16 by means of welding, or otherwise,

and an upper'set 21 and alower set 22 of V- type packing rings, which are separated by aspacer ring 23, are disposed between theabutment collar 20 and the'upper end ofthecoupling 24.' Thepacking rings 21 and 22 are turned in Opposite directions, and provide a fluid seal between thepa king mandrel 53 and thepacking tube 16 when the running tool is disposed in the mandrel.

V The coupling .24 is threadedly engaged to'the lower end, of thepacking tube 16 by right hand companion threads 25'and to the upper end of the lower tubular sect on' or shi tinsp uc i no w e v n tools therebelow.

. The anchor .cage assembly 31 includes a tubular body '32, which is threadedly engaged 'to 'the'sub 10 bybuttress threads 33, which are left hand threads, to permit disengagement of thesub 10 from the anchor cage body byright hand rotation of the tubing string.

. Aplurality of spring urgedfriction pads 34 are carried about theanchor cage body 32 and are urged into engage ment with the wall'of thewell 36 by thesprings 35. The

outward movement of thefriction pads 34 is limited'by 7 upper andlower limit rings 37 and 38, disposed about 37 and 38 is limited by the upper andlowerlimit shoulders 39 and 40, provided on the body v32.

A plurality ofupper slip segments 42, havingperipheral teeth 43 thereon, are spaced aboutthe lower end of theanchor cage body 32, saidslip segments 42 being disengageably interlocked with thebody 32 by means of the interlocking shoulders 44 a nd.45, provided on thebody 32 and the slips '42. -A.garter spring 46 is stretched about'the lower ends of the slips'42 to hold the slips in engagement with the upperexpander head '49.

Theslip segments 42 have interior, .taperedsurfaces 47 facing downwardly, which are in contact with, and co-act 'with, a corresponding, upwardly facing, taperedouter surface 50 on theupper expander head 42. Thesurfaces 47 and co-act to move theslip segments 42 outward- .ly'into engagement with the casing, when the expander running tool in the event the shear screws ,52 should become accidentally broken while lowering the packer in the'well casing. .This positively prevents the premature expansion andsetting of theupper slip segments 42;

A' plurality ofshear screws 52 frangibly connect the upperiexpanderhead 49 with thepacker mandrel 53. Thetubular packer mandrel 53 is threadedly connected to theadaptor coupling 14 by means Of buttressthreads 54; Thethreads 54 are left hand threads so that the adaptor coupling may be disconnected fromthemandrel 53 by right hand rotation of the tubing string, andsuch threads 54 are preferably buttress threads sothat they willsupport the axial'load of setting and expanding thepacker by upward pull on the tubingstring; l i

A base ringSS, forming an upwardly facingannular shoulder 79, is threadedly connected to themandrel 53 7 tends into thekey channel 58. Thekey screw 59 is free to move longitudinally'in thekey channel 58 but prevents relative rotation between theexpander head 49 and themandrel 53.

As shown in Figure I, thekey screw 59 is at the upper limit of thekey channel 58, wh'en the packer is assembled in relaxed position for running. 'Thus the key, screw 59 prevents upward movement of theexpander head 49 with relation to the mandrel to further safeguard against premature setting of the upper slips 42, in the event the shear 'screws52 should become accidentally broken while the packer is being run The keyscrew59 also holds themandrel 53 against rotationafter-the upper slips 42 are. set, to permit the threads '54 to be disengaged by right hand rotation of the tubing string, as will be hereinafter explained. Thekey channel 58 is long enough to' permit thekey screw 59 to move downwardly therein sufficient distance to allow the packer sleeve to be fully expanded and set (see Figures VI and VII). i V I Aconventional junk pusher 60 is threadedly engaged to the lower end ofthe'base ring 55 by right handcom panion threads 61. Aresilient sealing ring 62 is disposed between thebase ring 55 and thejunk pusher 60, said resilient sealing ring having a taperedouter face 68 thereon arranged to form a sealing surface for the V tapered sealingface 67 on thefiapper'valve 65.

The disc-shapedflapper valve 65 is of conventional construction and is spring urged inwardly by a coil spring (not shown) disposed about apivot pin 66, by which the flapper valve is pivotally attached to the junk pusher.

Thetubular member 26, extending through the packer assembly, holds theflapper valve 65 open, while the packer is being run, but when thetubular member 26 is withdrawn, theflapper valve 65 is permitted to close, by spring action, and theconical seating surface 67 thereon comes into contact with the sealingring 62 and closes and seals the axial passage through the packer, thereby confining fluid pressure below the packer. When pushed open, theflapper valve 65 may extend into acircular passage 69 provided in the wall of thejunk pusher 60.

Thejunk pusher 60 has a plurality offlow apertures 64 through the wall thereof to permit displacement of fluid therethrough as the packer is lowered in a column of fluid in the casing. An enlargedlower rim 63 is provided on thejunk pusher 60 to push debris and other obstructions in the well fluid ahead of the packer, as it is lowered into the casing, to prevent such foreign material from coming in contact with the lower slips 75 andexpander head 72, and from becoming lodged about the packer sleeve.

Thelower expander head 72, when assembled, as shown in Figure Ii, is abutted against an external, downwardly facing,annular shoulder 73, formed on themandrel 53.

Thelower expander head 72 has an external, tapered, downwardly facingsurface 74 thereon which is arranged to co-act with corresponding, internal, upwardly facing, tapered surfaces 77 on thelower slip segments 75. The plurality ofslip segments 75 haveperipheral teeth 76 on the outer surfaces thereof arranged to penetratingly engage the wall of thecasing 36 when theslips 75 are expanded by sliding coaction between thetapered surfaces 74 and 77.

The tapered surfaces 74 and 77 on theexpander head 72 and slipsegments 75 are placed in coinciding relationship, with theexpander head 72 abutted against theshoulder 73, and theslip segments 75 abutted against theupper face 79 of thebase ring 55. After being so positioned, theexpander head 72 and slipsegments 75 are frangibly connected together, and to themandrel 53, by shear screws 80. Agarter spring 78 is extending about theslip segments 75 to hold them in engagement with theexpander head 72, afterthe shear screws 80 have been broken, in the manner which will be hereinafter described.

Theshoulder 73 positively prevents the upward movement of theexpander head 72, with relation to the mandrel, while the packer is being lowered, which prohibits the premature expansion of the packer should thelower slip segments 75 become accidentally sheared from theexpander head 72. Theshoulder 73 has another important function which will be hereinafter explained.

Avertical bore 83 is formed in thebase ring 55, under eachslip segment 75, and acoil spring 84 is disposed in each said bore with the lower end thereof resting on the upper face of thejunk pusher 60. Apin 85, having anenlarged head 86 thereon, is movably disposed in each bore 83, and the upper end of said pin slidably extends through aguide hole 87, formed through the upper face of thebase ring 55. Thespring 84 contacts theenlarged head 86, and normally urges thepin 85 upwardly and outwardly of thebase ring 55, but when the packer is assembled thepin 85 is retracted, in thebase ring 55, against thespring 84. Theslip segments 75 are abutted against theupper face 79 of thebase ring 55 and fixed to theexpander head 72,as hereinbefore explained, to thereby retain thepins 85 in retracted position, while the packer is being lowered, as shown in Figure II. Thepins 85 remain in retracted position until the shear screws 89 are broken, at which time thesprings 84 relax and cause thepins 85 to push theslips 75 upwardly into engagement with the casing, as hereinafter explained.

An elongatedtubular packer sleeve 90, which is made of resilient material, such as a natural or synthetic rubber compound, is slidably disposed about themandrel 53, so that it is arranged to slide on the mandrel and be shortened and radially expanded between the expander heads 49 and 72, as thelower expander head 72 is moved upwardly by upward pull on the tubing string, after theslip segments 42 and 75 have been set against the wall of thecasing 36, in the manner hereinafter described.

Anupper retainer ring 91, made of relatively soft material, such as lead alloy, is disposed between the upper end of thepacker sleeve 90 and theupper expander head 49, and alower retainer ring 92, made of like material, is disposed between the lower end of thepacker sleeve 90 and thelower expander head 72. Therings 91 and 92 are arranged to expand upon contraction and expansion of the packer sleeve to prevent the resilient material of the packer. sleeve from flowing about the expander heads 49 and 72.

The well packer assembly, illustrated in the drawings, can best be understood by considering the operation and function thereof, which is described as follows:

The packer is assembled and attached to the running tool in the manner illustrated in Figures 1 and II. Thesub 10 is then attached to a tubing section and the tubing string is progressively made up by joining successive joints as the packer assembly, mounted on the running tool, is lowered into thecasing 36.

The running tool is made up of thesub 10, theupper tubular member 12, theanchor cage 31, theadapter coupling 14, the packingtube 16, thecoupling 24 and the lowertubular member 26. The running tool may be disengaged and removed from the packer after the packer is set in the casing.

It will be noted that all parts of the packer assembly are rigidly attached to, and carried by, the running tool as it is lowered into the casing. Thejunk pusher 60 is rigidly attached to themandrel 53, through thebase ring 55, and the mandrel is in turn secured to the run-, ning tool by thethreads 54 on theadaptor coupling 14. Through theadaptor coupling 14, thetubular member 12 and thesub 10, themandrel 53 is secured to the tubing string. Therefore, any impact or drag encountered by thejunk pusher 60, while the packer is being lowered,

will be transmitted to the running tool and therethrough to the tubing string, thereby eliminating the possibility of themandrel 53 moving upwardly to prematurely set the packer.

Thelower slip segments 75 are held in retracted position under theexpander head 72 by means of the shear screws which pass through theslip segments 75 andexpander head 72 into the wall of the mandrel. The shear screws 80 prevent theslip segments 75 from moving upwardly along the outer face of theexpander head 72 and they are prevented from moving downwardly by theupper face 79 of thebase ring 55. As so positioned theslip segments 75 hold the follower pins in retracted position.

The lower expander head 72is held in upward position by the shear screws 80, and is prevented from moving upwardly with relation to themandrel 53 by theannular shoulder 73. Thus there is no possibility of the packer becoming prematurely expanded while being run, because theexpander head 72 cannot move upwardly until the setting tool is released from theanchor cage 31 and pulled upwardly, as will be hereinafter described.

Theupper expander head 49 is held against downward movement by the shear screws 52 and against upward movement by theflange 18, which is in engagement with the upwardly facingshoulder 51, and by thekey screw 59, which is in engagement with the upper end of thekey channel 58.

Theupper slip segments 42 are held in retracted position against theexpander head 49 by thegarter spring 46,

and are held against axial movement with relation to the a to be unscrewed from the mandrel.

packer assembly by the interfitting engagement betweenthejshoulders 44 and 45 on theanchor cage body 32 and theslip segments 42, respectively.

Theanchor cage assembly 31 is'disengageably at tached to the tubing string by means of theleft hand threads 33,. The upper slips '42 cannot be expanded free of theanchor cage 31 and into engagement with the wall of the casing until thesub 10 hasbeen disengaged from the anohor cage by right hand rotation of the tubing string, to permittheupper expanderhead 49 to be raised.

and interact with theslips 42.'

, Therefore, it will be seen that all parts of the packer 7' '73. -Any'jar or-impact on theexpander head 72 will be effectively transferred through theshoulder '73-and absorbed by the running tool and the tubing string.

. When the packer assembly has been runto the desired depth where it is to be set, the tubing string isrotated to the right to disengage .thethreads 33. 'The friction pads 34are pressed against the wall of the casing, and in'frictional engagement therewith, to sufficient extent to hold theanchor'cage body 32 against rotation to permit a thethreads 33 to be disengaged. After disengagement .of j thethreads 33 the tubing string may be pulled upwardly, thus moving ,the running tool upwardly with relation to the anchor-cage 31, thefriction pads 34 serving to hold the anchor cage against upwardmovement.

,As shown in Figure IH, theupward movement of the running tool, and the packer assembly secured there to,

- causestheupper expander head 49 to slidably interact with the upperslip segments 42' and push theslips 42 out- 'wardly into anchoringengagement withthe casing 36. 'The interlocking shoulders.44 and 45 are freed of engagement, permitting theanchor cage 31 to be withdrawn with the running tool.

It will be noted that thethreads 54, which are also "left 'hand threads, are not disengaged by this initial rotation of the tubing string, becausesuch threads 54 cannot be unscreweduntil after thethreads 33 have been disengaged and theupper expander head 49 has been forced mtoftighhfrictional engagement with the ,upper slips 42* j andexpansion ring 91. Until the upper head49is thus heldagainst'rotatiomthere is no force for unscrewing themandrel 53 from theadaptorcoupling 14. After theupper expander head 49 has been secured against rotation,

themandrel 53 is held against rotation by thekey screw '59 and thekey slot 58 olpermit the adaptor coupling 14 'After the upper slips 42 have thus been permanently set against: the wall of .the casing 3 6, further upward movement ofthe tubing string and the running tool will ther raises theslips 75 above the lower end of theexpander head 72 which brings thelower end of theexpander head 72 into direct contact with the upper face of thebase ring 55, as shown in Figure V. This causes further force-of upward pull on the tubing string to be applied directly to theexpander head 72 and therethrough to thepacker sleeve 90; Simultaneously with this operation, thesprings 84 are recompressed to some extent as theslips 75 move upward into anchored engagement with the casing. However, thesprings 84 are strong enough to cause the follower pins 85 to holdthe slip-s 75 upward above the lower end of theexpander head 72 while thehead 72 is moved upwardly on base ring to expand thepacker sleeve 90;'as shown in Figures V and VI.

The resistance of thepacker sleeve 90 causes themandrel 53 to move upwardly with relation to theexpander head 72, thereby causing theshoulder 73 andhead 72 to separate. Theshoulder 73 thus moves upwardly into the body of thepacker sleeve 90, and the resilient material of the packer sleeve flows into the annular recess formed between such shoulder and the upper end of theexpander head 72, as thepacker sleeve is expanded as shown in Figure V.

Thus it will be seen that the entire force applied by upward pull on the tubing string is transmitted directly into expanding the rubber material of the packer sleeve.

' end ofexpander head 72 at all times'as the expander head is moved upwardly to expand the rubber material of the packer sleeve. Thesprings 84 and pins 85 move the lower slips 75 upwardly and maintain themin engagement with both thecasing 36 and thelower expander head 72 as the expander head is moved upwardly, but the slips are not used as a meansof transmitting the setting force to the rubber material of the packer sleeve. In other words, at all times while the compressive force is being applied to the rubber material of the packer sleeve thelower expander head 72 is in direct engagement with thebase ring 55, carried by themandrel 53. Therefore, no force is wasted in dragging. theslips 75 along the casing wall, becausethe slips are moved upwardly and held in engagement with thecasing 36 andexpander head 72 by the resilient force applied through thesprings 84 andpin 85. r r

It has been found that where the lower slips are used as a means of transferring the compressive force to the rubber material of the packer, as in previous packers, there is at least a loss of force by reason of the frictional drag between the slips and the casing wall. For instance, a 20,000 lb. pull on themandrel 53 would resuit in approximately 8,000 lbs. of actual compressive cause the shear screws 52, holding theupper head 49 to themandrel 53, to break. Such upward movement of running tool also causes the shear screws 80, holding the lower slips 75 tolower head 72, and to themandrel 53, to break,,seve ring theslips 75 fromhead 72, andhead 72 frommandrel 53. Thebreaking of the shear screws,

7 52 and .80 permits the mandrel 53to move'upwardly with 'head 72 from themandrel 53, thesprings 84 relax, pushing the follower pins 85 upwardly, simultaneously and 1 quickly moving thelower slip segments 75 upwardly along theexpander head 72 into uniform and aligned engagement with thecasing 36, as shown in Figure IV. e

Continued upward movement of the. tubing string,

7 carrying with it themandrel 53, and thebase ring 55, furforce applied to the rubber material: In using the present invention the full force of pull applied to the'tubing string is transmitted directly to the rubber, material of the packer and there is no loss of force, thus resulting in shorten arid radially expand the packer sleeve, thekey channel 58 has moved upwardly with relation tokey screw 59, as shown in Figure VI becauseexpander head 49 is held against upward movement by the set slips 42. Since theupper expander head 49 is now in tight compressive engagement with theupper slip segments 42, it is held against rotation sufiiciently to hold themandrel 53 against rotation through thekey screw 59and'key channel 58, to permit theadaptor ring 14 to be unthre'aded from themandrel 53 to thereby free the running tool from the mandrel, and packing assembly, carried thereon.

The running tool, including theupper tubular member 12, the packingtube 16, with packing thereon, lowertubular member 26 and anchor cage31, may then be raised upwardly on the tubing string, leaving the packer set in the casing (Figure VH), When the lowertubular member 26 is removed theflapper valve 65 is free to move upwardly to closed position as shown in Figure VII, to close and seal the axial passage through the packer assembly, to thereby confine fluid pressure below the packer.

After the running tool has thus been removed from the packer the well may be conditioned by circulation of fluid through the tubing string, if desired.

Various types of production, flow control and well servicing tools can be attached to the lower end of the running tool, either before the packer is initially run into the well, or they can be attached, and run through the packer, after the packer is set. The axial passage through the packer is of such diameter as to permit such tools to freely pass therethrough. These devices may include seating nipple assemblies, tail pipes, perforated and plain production tubes, chokes, lead-in subs, crossover equipment and many others.

The running tool, suspended on a tubing string, and with a well production or well servicing device attached to the lower end thereof, may be re-inserted in the packer as shown in Figure VIII, and provides a flow conduit through the packer which is sealed to the interior wall of themandrel 53 by the sealing rings 21 and 22. The running tool may be held down in the packer against pressure differential from below the packer by weight applied to the tubing string at the surface.

Means could be provided for relatching the running tool in the packer, but same is not illustrated herein as it forms no part of the present invention.

After the running tool has been run back into the packer as shown in Figure VIII, any weight applied to the tubing string will be transmitted from the running tool to themandrel 53 in downward direction, which will cause the mandrel to move downwardly through the rubber material of thepacker sleeve 90. Theshoulder 73, in effect, creates a differential piston which works against the fiowable rubber material, thus causing the downward movement of the mandrel to result in increased pressure in the rubber, which pressure is transmitted through the rubber to form a tighter seal with the casing. Therefore, increased weight applied to the mandrel is utilized in effecting a tighter seal, rather than weakening the seal, as would be the case if theshoulder 73 was not present.

Of course the packer could be used simply as a closure of the casing to confine fluid and pressure below the packer, as shown in Figure VII.

Theslips 42 and 75, theheads 49 and 72, thebase ring 55 andjunk pusher 60, are preferably made of drillable material such as cast iron, and themandrel 53, all screws employed, and theflapper valve 65 are preferably made of drillable material such as brass. Thepacker sleeve 90 is preferably made of canvas reinforced neoprene, which is also drillable. Therefore, all components of the packer assembly, which is anchored in the casing, are made of material which can be readily drilled up by the drill bit when it is desired to remove the packer.

It will thus be seen that there have been provided im provements in a well packer which insures against premature setting of the packer while it is being run, which provides means for applying all setting force directly to the packer sleeve, which assures suflicient expansion of the packer to form a positive seal with less force, which has increased sealing effect upon application of weight from above after setting, which provides a positive and simple means of disengaging the running tool from the packer assembly after it is set, and other advantages hereinbefore mentioned.

It will be understood that only a preferred embodiment of the invention has been disclosed herein and that other and further forms and embodiments may be made and still remain within the spirit and scope of the appended claims.

We claim:

1. In a well packer, a mandrel; a base member carried by the mandrel; a plurality of lower slips abutting against the base member; a lower expander head; frangible means connecting the lower expander head to the lower slips and to the mandrel, the lower slips and expander head having contacting tapered surfaces thereon arranged to slidably co-act to move the slips into engagement with a well casing; a resilient packer sleeve disposed about the mandrel above the lower expander head; an upper expander head; frangible means connecting the upper expander head to the mandrel above the packer sleeve; a plurality of upper slips; the upper slips and upper expander head having contacting tapered surfaces thereon arranged to co-act to move the slips into engagement with a well casing; a running tool extending through the mandrel and being threadedly engaged therewith; an anchor cage threadedly engaged to the upper end of the running tool and being disengageably interlocked with the upper slips; the said upper slips being movable radially out of engagement with the anchor cage by co-action with the upper expander head upon unthreading the running tool from the anchor cage and moving same upwardly therethrough; an elongated vertical key channel in the outer wall of the mandrel; and a key attached to the upper expander head and slidably disposed in the channel to hold the mandrel against rotation with respect to the expander head.

2. In a well packer, a mandrel; a base member carried by the mandrel; a plurality of lower slips abutting against the base member; a lower expander head; frangible means connecting the lower expander head to the lower slips and to the mandrel, the lower slips and expander head having contacting tapered surfaces thereon arranged to slidably co-act to move the slips into engagement with a well casing; a resilient packer sleeve disposed about the mandrel above the lower expander head; and external, downwardly facing, annular shoulder on the mandrel initially positioned against the lower expander head but arranged to move upwardly in the packer sleeve to provide an annular recess between the expander head and the shoulder in which the resilient material of the packer sleeve may flow when the mandrel is moved upwardly to expand the resilient packer sleeve; the said mandrel being free to move downwardly with relation to the lower expander head after the packer sleeve is expanded; an upper expander head; frangible means connecting the upper expander head to the mandrel above the packer sleeve; a plurality of upper slips; the upper slips and upper expander head having contacting tapered surfaces thereon arranged to co-act to move the slips into engagement with a well casing.

3. In a well packer, a mandrel; a base member carried by the mandrel; a plurality of spring urged members carried by the base, and being normally urged upwardly thereof; a plurality of lower slips abutting against the base member and holding the spring urged members in retracted position; a lower expander head; frangible means connecting the lower expander head to the lower slips and to the mandrel, the lower slips and expander head having contacting tapered surfaces thereon arranged to slidably co-act to move the slips into engagement with a well casing; a packer sleeve made of resilient material disposed about the mandrel above the lower expander head; an external annular shoulder on the mandrel initially positioned against the lower expander head but arranged to move upwardly in the packer sleeve to provide an annular recess between the expander head and the shoulder in which the resilient material of the packer sleevemay flow when themandrelis moved upwardly to expand the packer sleeve; said mandrel'being free to move j downwardly with relation to'the lower expander head after after :the packer sleeve is expanded; an upper expander headrfrangible means connecting vthe upper 'ex- 7 pander head to the mandrel abovelthe packerlsleeve; a

plurality of npper slips; the upper slips and upper ex? pander head having-contacting tapered surfaces thereon arranged to co-act to move-the slips into engagement with a well easing; the said spring iirg'edmembers being are R'eferencesCited in the file of this patent UNITED STATES PATENTS Baker et a1 May 17, 1938 Ian; 16, 1940 Burt Boyd et al. s Ian. 14, 1941 Bonner V ,May 1, 1951 Burns Mar. 18,1952, Morrisett V.. Mar. 18, 1952 Baker'et al. V May 27, 1952 Bream; June 17, 1952 Lee June 15, 1954 Ragan et a1. i Nov. 23, 1954 Baker V V June '19, 1956 luhvi

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