GB2380506A - A liner hanger with a plurality of slips - Google Patents

Abstract

A liner hanger comprises a body, a plurality of slips mounted to individual seats on the body, where the seats are circumferentially spaced from each other creating longitudinal passages (38) outside the body where wellbore fluids may flow. Upon actuation of the slips, load is transferred to the body from each slip through its individual seat.

Description

LINEl;t HANGER 5 The field of this invention relates to liner hangers,

and, more particularly, to the techniques

for securing liner hangers in well bores.

Liner hangers are secured in the well bores by slips. Actuation systems for such slips in the 10 past have employed foil circumference hydraulically actuated pistons to move the slips. These designs presented a pressure rating problem in that the full circumference piston Frequently had a maximum working pressure significantly loiterer Han the mandrel which it surrounded. Thus, this type of design limited the maximum vaporing pressure in He suing to the rating of the cylindrical piston housing assembly. For example, it was not unusual in. prior designs to have mandrels rated 15 for 12,000 PS! while the surrounding cylinder housing for the cylindrical piston to onlyhave a rating of approximately 3,000 PSI. id an effort to improve the shortcoming of this design, another design illustrated in U.S. Patent 5,417,288 was developed. this design the mandrel body received a pair of bores straddling each of the slips. piston assembly vitas mounted in each of the boms with all of the necessary Seals. The application of hydraulic pressure in He mandrel into all the piston bores 2 0 actuated the pistons on either side of each slip through a common sleeve to which all tho slips were attached. This design, ho vevcr, v,ras expensive to manufacture and had many potential leak paws in the Arm of the ring seals on each of the pistons wherein each slip required two pistons, This design, however, did provide for a liigher pressure rating for the liner hanger body, It also used the hydraulic pressure directly to actuate the slips. Necessarily it did not include a locldag feature 2 5 against pIematu:re slip movements due to inadvertently applied pressures. The design in the U.S. Patent 5,417 288 also did not provide for flexibility for changed conditions down-hole which could

require additional force to set the slips. In essence, each application seas designed for a pre-existing set of conditions with field variability not included as a feature of that prior art design.

Slip assemblies in the past have been configured in a variety of ways. 1h one configuration, when the slips am actuated, the load is passed through the slips circumferentially througl, their 5 guides or retainers and transmission of the load to the underlying mandrel is avoided. In other mom traditional designs, the slips are driven along tapered surfaces of a supporting cone and tile loading is placed on the supporting mandrel is in a radial direction toward its center, thus tending to deform the mandrel when setting the slips. Typical of such applications are U.S. Patent& 4,762,177, 4,711,326 and 5,086,845.

10 The design of the liner hanger needs to accommodate circulation of mud and cement, The prior designs, particularly those using a cylindrical piston, obstructed the passages that could have been used for circulating cement and mud.

The apparatu& of the present invention has many objectives. A versatile actuation system for a locking &yStetI1 is provided. The apparatus USES a combination of hydraulic pressure to defeat: a 15 locking mechanism which in turn allows mechanical actuation of the slips. The slips are configured to pass the loading into the slip seat and then into the mandrel in a manner so as not to defonn the rn ndrel. The slips act independently of each other and transfer their load through the surrounding slip seat directly to the mantel. The slip seats are attached to the mandrel without welding because standard setting organizations and well operators have restrictions against connecting parts made of 2 0 certain materials by welding or against welding altogether in down-l1ole tools. The elip seats are spaced imm each other to provide flow channels along the exterior of the liner hanger to facilitate the movement of cement or mud. Those passages Pre continued for the length of the tool. The actuating piston assembly to defeat the lock mechanism is a bolt-on arrangetnent which can be readily interchanged in the field to react to changing down-hole conditions. The actuating piston is

2 5 fully compensated for thennal effects and a system is provided to vent any gases f ram the piston actuation system which is used to defeat the lock. The lock can be in a number of alternative styles.

One of which involves using a dog to hold the parts together for run in and liberating the dog from its groove to allow setting of the slips, which is preferably done by a plurs lity of springs. The parts are also disposed in a preferred spacing to make maximum use of the limited force available from

the piston assembly for releasing the lock, The lock configuration can qIso be in the form of a split dug held together by a yoke which allows relative movement when the yoke is shifted, alloying the split ring to expand. These and other objectives of the present invention will become more apparent to those skilled in the art from a review of the preferred and alternative embodiments described 5 below, A liner hanger assembly has a slip actuation system which is locked for run-in, A piston assembly bolts onto the mandrel in a sealable manner to actuate a mechanical lock, Upon release 10 of the lock, a plurality of springs actuate a sleeve which is in tom attached to Me slips to move them relative to their slip seats, In an alternative embodiment, a plurality of springs can directly move the slips relative to their slip seats, when the springs are released. The slip seats are preferably mounted to the mandrel without welding and have longitudinal spaces for mud or cement flow erebetvveen.

Load is distributed from each slip through its slip seat into the mandrel without interaction from an 15 adjacent slip or slip seat, A rupture disk ensures that a predetenn ned pressure is built up before the piston can actuate to defeat the lock. The lock can come in a variety of conflgoration6. One of which is a sliding sleeve over a dog and another is a yolce over a split nng which, when shifted, allows the split ring to expand, thus unlocking the parts. Yet another venant is a yoke restraining a split ring, The slips can also be configured to allow flow of mud or cement behind them, thus 2 0 reducing We resistance to flow of such materials.

- FIGS. 1A through C are a plan Viesv of the apparatus looking down on the spring housing; FIG. is a rotated view from He view of FIGS. 1A and B showing a plan view of the lock 2 5 housing; FIG, 3 is a section view through lines 3-3 of Em. 2; FIG. 4 is a section of lines 44 of FIG. 2; FIG. 5 is a section through lines 5-5 of FIG. 2; Fl:G, 6 is a section through lines 6-6 of FIG. 2;

PI G. 7A through C me a section view though the lock housing ding the runin position; FIG. 8 is the section view through the piston housing in the set portion when the lock has been defeated.; FIG, 9 illustrates the connection between Me spring housing and We gage nag, 5 FIG 10 illustrates He springs used to set the slips and me guide for each spring in section through either the spring housing or the lock housing.

FIG. 11 is a top view showing the longitudinal passages that facilitate the flow of cement or mud: FIG. 12 is section view through the piston housing retainer bolt shoving the passages 1 0 therethrough, FIG. 13 is a section view through the piston housing showing the passages from Me retainer bolt to the rapture dials location; FIG. 14 is a plan view of one of the slips; PIG. 15 is a perspective view of the same slip shown in FIG. 14, showing the slip in 15 perspective and the sloping end surfaces; FIG. 16 is a plan view of the lock dog retainer; FIG. 17 is a section view Trough lines 17-17 in FIG. 16; FIG. 18 is a section view of the loci; dog; FIG. 19 is a plan view of the lock dog release 2 0 FIG. 20 is a section view through lines 20-20 of FIG. 19: - FIG. 21 is a partial section through the longitudinal interior passage in He loci; housing which in part holds the locking dog; FIG. 22 is a plan view of the lock housing; FIG. 33 is a plan view of He slip seat; 25 FIG. 24 is a section view through lines 24- 4 of FIG. 23; FIG. 25 iB a section view Trough lines 25-25 of FIG. 24 FIG. 26 is a section through the slip seat retainer, FIG. 27 is a plan view of the mandrel; FIG. 2B is a more detailed plan view of the mandrel:

FIG. 29 is a section through lines 2929 of FIG. 28; FIG. 30 is, a section view of an alternative embodiment taken through one of the slips, FIG. 31 is a plan view of the slip shown in FIG. 30 taken along line 31-31 of FIG. 30.

FlG. 32 A through C me the view of FIGS. 30 A through C rotated so show the spring 5 housings; FIGS. 33 A through C are the view of FIGS. 30 A through C rotated to show the spring housings, FIGS. 33 A through C are the view of FIGS. 30 A through C: further rotated to show the locking feature: O FIG. 34 is an elevation view of the snap ring; FIG. 35 is an isometric view of the internal key; PIG. 36 is a view taken along lines 36 - 36 of FIG. 31' FIG. 36a illustrates a longitudinal cross section of the tool Trough He piston assembly, lock mechanism, slip and slip seat, 15 FIG. 37 is a plan view of the tool in the set position.

FIG. 38 is a plan view of the tool in the run-in position.

FIG. 39 is a section view of the piston asseInblg sad lock mechanism in the run-in position.

FIG. 40 is section view of the piston assembly and lock mechanism in Me set position.

FIG. 41 is a section view through FIG. 39, of the piston assembly bolted to We mandrel.

2 0 FIG. 42 is an end view of the lock.

- FIG. 43 is an end view of Me snap ring.

Refemng to FIGS. 1 through 11' the major components of the apparatus in A will now be 25 described. Apparatus A has a mandrel 10 which has a lower end 12. Lower end 12 is shown schematically and 06e skiDed in the win appreciate that He liner Tong is connected at lower end 12. The mandrel 10 has an upper end 14 to which those skillet in the art will appreciate is attached a Dunning string for proper positioning of securing assembly S shown in FIGS. 1A through C, The mandrel 10 has a shoulder 16 which defines a reduced diameter segment 18.

A gage ring 20 is shown in FIGS. 1A and in section in FIG. 3. The gage ring 20 has a split 22 (see FIG. 3) and a draw bolt 24 so as to bung the components of Me gage ring 20 together at split 22 once the gage ring 20 has been advanced beyond the shoulder 16 and onto the reduced diameter seamen: 18. Gage ring 20 has several flats, one of which 26 is shown in interrupted form in FIG. 5 9. FIG. 9 is a section view Trough the gage ring 20 showing the spring housing 28 mounted to it.

By companug FIGS, 1A and 9, it can be seen that the spun" housing as has a tal'30 Which extends into a window 37 in flat 2fi of gage ring 20. In that manner as shown in FIG. 9, the position of the spring housing 28 is initially fixed to the gage nag 20 and that engagement is secured by bolts 34.

FIG. 2 shows rotated view fram FIGS. 1A and B. indicating that the gage ring 20 also 10 supports the loci: housing 36, The number of spring housings 28 can vary without departing fron the spirit of the invention. In the preferred embodiment disclosed, there are three spun" housings 28 and one lock housing 36, generally at 90 degree spacings, thus defining elongated passages 38 therebetween(seeFIG.11), thesepassages 38 shownschematicall',inFIG. 1B allow mudorcement to pass relatively unimpeded.

15 Refemng again to FIG, 2, die look housing 36 is secured to the gage ring 20 by bolts 34 Refemag to FIG. 22, a top view of the lock housing 36 is illustrated. It has a top end 40 adjacent to which are the openings 42 through which the bolts 34 are inserted. Also allows in hidden lines is a downward! fir oriented tab 44 which is placed Trough a corresponding opening or window in Me gage dog 20, similar to the method of attachment shown in FIG. 1A. The lock housing 36 also has 20 an extending arm 46 which is rectangular in cross-section and includes a receptacle 48 for engagement of a slip 50 (see FIG 1B). It should be noted that FIG. 1B illustrates in dashed lines Me movement of receptacle 48 into a second position which reflects the setting of Tic slip 50. Arm 46, shown in FIG. 22 also has an oblong undercut 52 which fits into slot S4 of slip seat retuner S6 (see FIGS. 26 and 1B). that manner the slot 54 acts as a guide to Me longitudinal motion of lock 2 5 housing 36. It also holds aim 46 against centrifugal force created by rotation of the apparatus A at speeds as high as about 250 RPM. The same configuration is found in die spring housing 28 shown in FIGS. 1A through C employing the identical undercut 52 with the same slip seat retainer 56 providing a slot 54 to guide an arty 46 which in turn through receptacle 48 secures yet another slip 50. It should be noted that FIG. 2 is a partial view of the lock housing 36 shown in a rotated

position from the view of FIG, 29 and therefore, it does not show the arm 46 or receptacle 48 at the end of it v, hich is used to co,mect to a slip 50. Refe'Ting again to FTG. 22. the lock housing 36 has a series otblind bores 58, two of which are shown in FIG. 22 in hidden lines. A section through one of the blind bores 58 is seen in FIG. 10. There, a spring 60 surrounds a spnug retainer 62, the 5 me-in position, the spring 60 is. compressed so that when the lock mechanism L is released, Me energy stored in spring 60 is also released allowing upward movement of the gage ring 20 as shown by com,panng PIGS. 7 and 8. Initially, ho,,veve;, each of the spring housings 28 has a plurality of blind bores 58 (see FIG. 1B), each of which has a spnug 60 and a retainer 62 mounted therein, The number of springs and the size of the r.p ing 60 can vary without departing from the spirit of We 10 invention, Those skilled in the art will appreciate that the number of available spring 60 and their size will dictate tile amount of upward force that can be exerted on gage ring an which puns up with it the spnug housing 2B and the lock housing 36, which in turn pull slips 50 relative to slip seat 64, securing assembly S to a tubular in the well bore.: One version of the lock mechanism L will now be described. The lock housing 36 has a 15 multi-dimensional longitudinal opening 66 (see FIG, 22). As shown in E1G 22, the opening 66 extends for a significant length of the piece and then continues as a bore 68 which has a generally rectangular cross-section With a downwardly depending opening 70, shown in hidden lines in FIG, 22 and a subsequent upwardly depending opening 72, These features can be better seen in the section view of the lock housmg 36 illustrated iD FIG. 21, In FIG 21, bore 68 is illustrated who 2 0 an opening 74 for insertion of a breakable pin 16 (see FIG. 7B). Further down bore 68 is another - - opening 78 for the insertion of a guide pin 80 (see FI(:, 7A). 17inslly, Tic downwardly oriented opening 70 and upwardly oriented opening 7Z are illustrated as well as one opening 42 for attachment to We gage nag 20. The downwardly oriented opening 70 accepts a dog 82. Its tapered up-hole and down-hole surfaces 84 and 86 (see EIG. 18) are illustrated to be disposed at preferably 2 5 an 80 degree angle measured from the lower end 88 of dog 83, Dog 82 sits in notch 90 on the riandrel 10 as shown in FIG. 7A, Notch 90 has tapered surfaces conforming to the tapered surfaces 84 and 86 of dog 82, While 80 degrees is preferred, other angles can be used without departing from the spins of the invention, The matching taper angles between the dog 82 and the receptacle 90 facilitate in driving the dog 82 out of receptacle 90. In the run-in position shown in FIG 7A, the

dog 82 is retained by lock dog retainer 92. As show in FIGS. 7A and B. the lock dog retainer 92 overlays the dog 82 holding it in the notch 9d on mandrel 10, Refemng to FIG. 16 which is a top view of the lock dog retainer 92, an elongated slot 94 accepts the guide pin 80 which extends through the lock housing 36. In that manner, the guide pin 80 limits the down-hole movement of lock dog 5 retainer 92. This concept is illustrated in FIG. 16 by placement of guide pin 80 in the slot 94 to illustrate that only movement up-hole or to the left in FIG. 16 is possible for lock dog retainer 92.

Lock dog retainer 92 has receptacle 96 shown in FI(. 16, As shown in FIGS, 19 and 20, receptacle 96 accommodates tab 98 of lock dog release 100, an important feature, the width of tab 98 is shorter than the length of receptacle 96, thus allowing for the possibility of relative motion 1. O therebetween. For the n n-in position, the lock dog release 100 has a receptacle 102 (see FIGS. 19 and 20) which accepts put 76, which in turn extends through the loci; housing 36. Thus, for run-in, the lock dog release 100 is pinned to the lock housing 3G and has a tab 98 inserted into receptacle g6 of lock dog retainer 92. FIG. 16 shows the maximum down-hole position of lock dog retainer 92 due to the Gavel linutadon of guide pin 80 extending into slot 94, tl e position shown in FIG, 15 16, the tab 98 of lock dog release 100 is so positioned in receptacle 96 so as to be able to move up hole, i.e. toward pin 80 for a limited distance before tandem movement of lock dog Please 100 and lock dog retuner 92 occurs. The significance of the relative movement will be explained later.

Refemug to the section view of the lock dog retainer 92 (FIG. 17), it can also be seen that it has an undercut 104 which is offset from dog 82 in FIGS. 7A and 11. and shifted to coincide with 2 0 dog 82 in FIG. 8. Those skilled in the att will appreciate that when the undercut 104 moves over the dog 82 the dog can be pushed out of notch 90, thus allowing err unlocidug of the lock housing 36 from the mandrel 10. As previously explained, when such unlocl;ing of the lock mechanism L occurs, the VanOUfi spnugs 60 bearing on their respective retainers 62 collectively expand up hole, moving the spring housings as and the lock}lousing 36, along with gage Hug 20 to which longs 2 5 as and 36 are connected, which has the ultimate expect of pulling the slips 50 to set them' order to actuate Me lock mechanism L to unlock and permit setting of the slips 50 a release device is required. In this instance, the release device comprises a piston housing 106 which has internal passages which are best seen in FIG, 13. Passage 108 accepts a bolt 1lO whose details are best shovel in FIG. 12, Bolt 110 is placed over an opening 112 in the mandrel 10. The piston

housing 106 has a circular groove 114 which accepts a sealing member, such as an O-nng 116 (see PIG. 7B). With bolt 110 securing Me piston housing 106 about the opening 112, thee is a sealed passage from inside We mandrel 10 through the bolt 110, through its passage 118 (see ETG. 12), Passage 118 in bolt 110 is sealingly aligned to passage Lao in piston horsing 106. Passage 120 leads s to passage 122 within which are mounted a rupture disk 174 and a piston assembly 126 (see FIG. 7B). FIG. 7B shows the rupture dials 124 adjacent the piston assembly 126 all within the passage 122 of the piston housing IB6. The purpose of Me rupture disk 1 is to insure that a certain minimum pressure is achieved in the mandrel 10 before internal pressure in mandrel 10 is 10 com uunicatedto thepiston assemblyl26. The piston assembly 126 has acen alpassage 128 which can be sealed by a cap 130 in combination with a seal 132. Externally, the piston assembly 126 has a seal 134 to seal it in passage 122 for reciprocal movement therein. The cap 130 allows proper displacement of air or other gases from passage 122 as tl e piston assembly 126 is inserted into Me passage 122. Upon insertion to the position shown in FILL 7B, the trapped fluids are displaced 15 through passage 1a8 until the desired position of the piston assembly 126 is reached. At that time, the cap 130 is screwed on, sealing off the piston assembly 12G in passage 122. Priorto installing the piston assembly lad, the ntpture disk 124 is inserted, I he piston assembly 126 is thus free to move in opposed directions to compensate for thermal effects or odor effects. As shown in FIG. 7B, there is a space between the piston assembly 126 extending out of the piston housing 106 and Me lock dog 2 0 release 100. This space can also be easily seen in FIG. a. Pose skilled in me art will appreciate that the piston housing lob as well as the piston assembly 126 which is in it, can be easily replaced with a different sized unit to accommodate these specific down hole conditions as they occur. Such replacements can be done in the field without having to send the tool back to the shop. What is

simply done is that the but 110 is loosened and different piston housing 106, having a bigger or 2 5 smaller piston, or with a rupture disk 124 set to break at a different value is easily insertible as a unit in replacement of Me original equipment. Thus the bolt-on [nature of Me piston housing 10G holding the piston assembly 126 adds versatility to the apparatus A of Me present invention and allows for field changes to meet last minute changes in wolf operating conditions where Me apparatus A is to

be Bet. It also facilitate& the presence of passage& 38.

In order to set the slips 50, pressure must be built up sufficiently within Me mandrel lit to break the rupture disk 124. When the rapture disk 124 breaks, pressure is then applied to We piston assembly 126, moving the piston to We left as seen by comparing PIGS. 7B and 8B. The piston assembly 126 first impacts the lock-dog release loo, pushing it up hole. As seen ill FIG. a, the lock 5 dog release 100 has a downwardly oriented tab 136 adjacent to an opening 138. As shown in FIGS. 7A 5z B. the lock dog release 100 is initially retained by a shear pin 76 or similar retaining device.

The impact of the piston assignably 126 on the lock-dog release lDO breaks the shear pin 76 and starts the lock-dog release 100 moving up hole. It should be noted that at this time there is no movement of the lock-dog retuner 92. As previously explained' the receptacle 96 of the lock-dog retainer 92 10 (see FIG. l6) is longer than the width of the tab 98 on lock-dog release loo. As a result, the energy imparted into the piston assembly 126 i s initially Upended solely to break the shear pin 76 Without also, at the same time, having a need to overcome the frictional resistance between We lock-dog retainer 92 and the dog 8Z, Which it sneezes into notch 90. Those skilled in We art will appreciate that Were movements occur almost instantaneously so that after the shear pin 76 is broken and the 15 piston assembly 136 is moving in tandem with lock-dog release 100, We lock-dog retainer 92 is eventually driven up hole as shown In FIG. 8A. This places the undercut 104 (see FIG. 17) in ali0Tument with doll 82. Further movement of locl -dog retainer 92 allows springs 60 to push lock housing 36 which in Am forces tapered surface 84 of dog 8a along its parallel Butte in notch go so that the dog 82 comes out of Hotels 90 to the final position show in FIG. 8A. It should be noted 2 0 that as these movements are occumog, the tab 136 pushes any mud out through opening 138 in lock dog release 100. Si rularly, the uphold movement of lock-dog retainer 92 forces any adjacent mud through the upwardly oriented opening 72 in the lock housing 36.

Win the dog 82 out of notch 9O, Me spring housings 28 and lock housing 36 are no longer held to Me mandrel 10. At that point, the 8pnugs 60 in the various spun" housings 28 and the lock 2 5 housing 36 can push otE against their respective retainers 62, thus moving uphole all of the spring housings 28 and lock housing 3G along with gauge ring 20. This upward movement shown by a comparison of FIGS. 7 & 8 results in a pull update on all of the slips 50 which drives the slips SO outwardly into a gripping engagement with the tubular in the well bore to set the apparatus A.

The method of secunug the slips S0 to the respective slips seat 64 will now be described, Each of the slip seats 64 can be attached to the reduced dieter segment 18 of the mandrel 10 without welding. This is a distinct advantage to well operators whose requirements preclude welding as well as when certain materials are used allowing the afflxation of the slip seat 64 to the mandrel 5 10 in conhnnance with regulations that prohibit welding, such as those promulgated by the Natione1 Association of Corrosion Engineers ( ACE). The mandrel 10 is shown In more detain in FIGS. 27 through 29. As seen in FIG. 27, each slip seat fi4 is attachable to the mandrel 10 through a series of roves of longitudinal slots 140. Bach individual slot 140 is shown in greater detail in FIG. 28.

At least one opposed pair of slots, shown in FIG 28' has a lateral opening 142, which is designed 10 to accept a tab 144 (see FIG. 25) on the underside of the slip seat 64. ISe various tabs on the underside of the slip seat 64 are aligned with the longitudinal slots 140 and more particular!., the lateral openings 142. The slots 140 have elongated undercuts 146 such that the tab 144 on the underside of Me slip seat 64 can be first inserted into the lateral opening 142 as shown in FIG. 28 and then the slip seat 64 can be moved longitudinally avid respect to mandrel 10 to put the tabs 144 15 in an offset position from lateral opening 142. This position is shown in FIG. 27. A180 shown in FIG. 27 is an opening 148 in the mandrel 10. Opening 148 is in fact a depression in the outer surface of mandrel 10. Referring to FIG. 24, the slip seat 64 has a transverse lug 158 which fits into We opening 148 and mandrel 10. Opening 148 is necessarily larger than the lug 150 so that upon insertion of tabs 144 and lug 150 into respective openings 140 and 148 and translation of the slip seat 2 0 64 with respect to the mandrel 1O, any load transmitted to Me slip seat 64 goes into the mandrel 10 C vi a transverse lug 150 and aligned lugs 144, essence, IUSB 144 takes a hanging load on upper ends of sloes t40 and talce up a radial load on the sides of slots 140 while transverse lug 150 bears on the upper end of opening 148. To finally fix Me Blip seat 64 to the mandrel 10, a slip seat retainer 56 is inserted through an opening 152 in the slip seat 64 and furler into a notch 154 in the mandrel 10 2 5 (see FIGS. 23 & 27) Bach of Be slip seat 64 ate attached to the mandrel 10 which does not deform the mandrel 10 in the identical manner. While a specific non- welding mode of attachment of slip seat 64 to mandrel 10 is disclosed, those skilled in the art will appreciate that over techniques for so joining Bose two components can be utilized without departing from Me spins of the invention.

Another feature of the apparatus A of the present invention is Me manner in which We loading is transferred Tom the slip 50 to the slip seat 64 and into the mandrel 10, leach individual slip 50 transfers loading to Me slip seat 64 which surrounds it, whereupon the loading through the shape of the slip 50 is transferred into the wail of the mandrel 10. There is no interaction between 5 one slip 50 and its slip seat 64 and any other slip seat 64. The loading is t ransfened from each slip 50 into the wall of mandrel 10 through slip seat 64 rather than radially toward the center of mandrel 10, which would be a force that would tend to deform or crush the mandrel 10. preferring specifically to FIGS. 23 and 14 and IS, it can be seen that the edges 156 and 158 are preferably beveled with respect to the plane of the paper and there is a matching slope on surfaces 160 & 162 10 of the slip seat 64, Thus, taking into consideration the strength of the slip seat 64, the edge configuration of each slip 50 along surfaces 1.98 & 1S6 and the conformlag surfaces on the slip seat 64 surfaces IG0 & 162 are such that the resultant force from loading a slip 50 is a force that is merely close to taIIgendal to the vial hick comprises the mandrel 10. In the preferred embodiment, the angle is approximately 80 degrees, putting the greatest component of force closer to the tangential 15 direction into the wall which comprises the mandrel 10 with smaller component directed radially toward the central of the mandrel 10. Such angles can be placed in the slip 50 by repositioning it dunug the machining process. As can beseen in looldug at FIG. 23, when Me upward pull comes to each of the slips 50, they are guided by surfaces 160 & 162 to move radially outwardly to lock the apparatus A downhole, while at the same time, independently transtemng load from each slip to its 2 0 respective slip seat 64 through surfaces 160 162 which are preferably at a slope of about 80 degrees resulting in the largest component of force being transferred into Me mandrel 10 in a near tangential manner.

Those skilled in the art will now appreciate that the above-described preferred embodiment has numerous advantageous over tools in the prior art, The apparatus A employs a mechanical lock

2 5 which prevents premature settings, It uses a boll:-on piston housing 106 which allows for field

replacements to obtain different forces for disabling the mechanical lock. The rupture disk 1Z4 requires a pre-determlned pressure be applied before the loci; mechanism L can release, The use of a bolt-on piston housing 10G also helps reduce the profile of the look mechanism L and enables the provision of longitudinal passages 38 for the passage of mud and cement. The slips 50 are secured

to slip seat 64 which are, in tom, connected to We mandrel 10 without welding Each slip 50 is configured to direct applied loads into the mandrel 10 in a direction nearly approximating the tangential orinto the wall of the mandrel 10, Thus there is less of a tendency to deform the mandrel as with designs of the prior art which simply move slips Up cones. Additionally, as scin ished

5 from other slip designs of the prior art, there is no interaction in sharing the load among the slips 50.

Each slip individually distributes the load applied to it to the n:. andrel 10 through the slip seat 64, The piston assembly 126 through Me use of cap 130 allows venting of funds from passage 123 it, the piston housing 106. The piston assembly 126 is free to move in both directions to react to vernal and other effects. The rupture disk 124 can be configured so that it ruptures at significantly 10 higher pressures upon an excess of pressure in passage 1:Z] as opposed to its normal operation where an increase in pressure frown the mandrel 10 results in breaking of the rupture disk 124. Maximum use is made of the force generated by the piston assembly t26 through Me lost motion between the lock dog release 100 and the lock dog retuner 92. Since rotation of Me apparatus is possible, provisions have been made to retain Me awns 46 which are attached to the slips 50 against oentufugal 15 force from such rotation. The slip seat retainer 56 accomplishes this function. Yet another new feature is the drop-in arrangement for the slip seat 64 into the slots 140 and opening 1 18. The dove tail arrangement also helps to secure the slip seat 64 to the mandrel 10. The edge slopes on the slips 50 are designed to avoid over stressing the Blip seat C4 while at Me same time efficiently co Tununicating loads on each slip 50 into the wall which defines the mandrel 10.

2 0 Refemng now through FIGS, 30 through 36, an alterna dve embodiment is described As shown in FIGS. 30 A through C, a mandrel lC0 has a series of slips 162 retained in a similar manner as previously described for the slips 50. What is different in the alternative embodiment can be seen in FIG. 33A where a passage IC4 leads from internally of the mandrel 160 to a rupture disk 166, On the other side of the rupture disk 166 is a piston assembly 168. These components operate in the 2 5 identical manner as described for the comparable structure in the preferred embodiment. Looldng at FIG. 32B, a spring housing 170 is looked to the mandrel 160 by virtue of the fact that a split ring 172 extends into a groove 174 in the mandrel lC0. The split nug 172 also extends into a recess 176 in spring housing 170. spring 178 is shown in FIG. 3213. Those skilled in the art will appreciate it as one of many springs 178, each of Which is guided by a guide 180, Refemug to l;lG. 31, the

lower end 182 of the spring housing 170 has a recess 184 which accepts a tab 186 Which is part of Me structure of the slip 162. Accordingly, the span" housing 1lB is operably connected to all the slips 162 and has numerous springs 178 which will drive all the slips 162 upward as the spun" housing 170 moves upwardly once the split ring 172 is moved out of the way, This occurs when the 5 split nag 172 is allowed to expand effectively out of groove 174 thereby no longer restraining Me spnnghousing 110 end thus allowing the force oPall the springs 178 to move the slips 162 upwardly, Gus distributing the load on each of the slips 16;l in the manner previously described for the preferred embodiment. The split ring 172 is shown in FIG. 34. It has a pair of opposed shoulders 188 190 which are tightly squeezed together by a yoke 192 (shown in FIG. 35). Yolk 193 has a 10 pair of opposed surfaces 194 & 196 which engage surfaces 190 188 respectively to hold the position of the split ring 172 to a diameter sufficiently sluall so that it can effectively serve 86 an anchor when fixed in groove 174. The release simply occurs by a pressure buildup in the mandrel 160 which is communicated through passage 164 to break rupture disk 166 which in turn actuates the piston assembly 168. The piston assembly 168 engages a connecting rod 198 which is fixedly 1 S secured to the yoke 192. When the surfaces 194 & 196 on yoke 192 are displaced from the surfaces 190 & 188 on split ring 112, lbe split ring 172 can expand radially outwardly, thus defeating the lock of Me spring housing 170 to Me mandrel 160. When this occurs, the springs 178 can bias We spring housing 170 upwardly, thus taking up all the slips 162 and securing Me apparatus while distributing the load into the mandrel 160 in the manner previously described.

2 0 Yet another feature of the alternative embodiment can be seen from FIGS, 31 &: 36. As ::. i shown in FIG. 36, a flow channel 200 on the back side of each slip 162 allows mud or cement flow underneath to permit circulation of such materials dunug Me normal operation of the apparatus A. This is significant in this particular design because it does not have the feature of the longitudinal passages 38 as in the preferred embodiment. However, in common with the preferred embodiment, 5 pressure in the mandrel Leo results in defeat of a look mechanism (in this embodiment the split rug 172). The slips 162 are independently set with the spring force from spnugs 178. This mode of operation is to be contrasted with Mat revealed in U.S. Patent No. 5,417,288 where the pistons acetate a ring which is directly connected to We slips. Thus, in that design tile hydraulic pressure actually moves the slips whereas in this alternative embodiment, as well as in the preferred

- embodiment, the applied hydraulic pressure, without breaking any components other than a rupture disk such as 1Z4 and shear pin 76, results in the release of a mechanical lock which allows Me independent operation of He setting of the slips 50. Again, comparing to the previous technique of U.S, Patent 5,417,288, numerous passages have to be drilledin the mandrel. More specifically, two 5 passages were needed for eacll slip to operate it. Here, a single passage is presented through the mandrel 160 to operate the connecting rod I98 so as to release He split ring 173 mom He groove 174 thus allowing independent mechanical actuation using spring force to set the slips 162.

Referring to FIG, 36a, one alten lve embodiment of the liner hanger is composed of a mantel 201 which has a lower end 217, The lower end is shown schematically and those slrilled 10 in He art will appreciate that the liner string is connected at the lower end 217. The mandrel 201 has an upper end 216 which, to those sldlled in the art will appreciate, is attached to a running tool for proper positioning and securing of assembly S shown in FIGS. 3Sa through 38.

Referring to FIG. Ma, a piston assembly 202 is secured to the mandrel 201 using a bolt 110 previously described. Secured loosely by the piston assembl r282'is a lockbar 203. which connects 15 to the snap ring 304, which extends into a recess 205 (FIGS. 39 and 40) on the mandrel 201, and is retained in place by a breakable pin 206. The pusher sleeve 207 is biased against the snap hug 205 through the t-slot segment 212, which is biased by the slip 50, which is biased by the spring 60 though the spring guide 62.

One alternative embodiment of He piston housing 223 can best be seen in FIG 39 in He run 2 0 in and FIG 40 in He set position, where He end of the piston housing 223 has been extended to present a cover Il8 over the lock bar 203 to prevent shifting of the lock bar 2 03 by means over that the piston 126. The lock bar 203 is similar to the yoke 192 in that it combines the yoke 192 slid the connecting rod 198 Tom the previous description. The lock bar 203 has a pair of opposed surfaces

219 & 220 GIG. 42) which hold the opposed shoulders 212 222 (FIG. 43) respectively of the 35 snap ring 204 and secure He snap dug 204 in the recess 205 in the mandrel 201. This method demonstrates that He snap nag 204 can be restrained Mom the top or the bottom Bailout departing from Me spirit of the invention.

Another alternative embodiment of tile piston housing 223 is that it can be mounted on milled flat FIG. 41 on the mandrel, verses mounting on a curved surface FIG. 6 of the mandrel 201 &:10 without departing from the spins of the invention.

The alternative embodiment of the slip seat 209, where the springs 60 are contained in the 5 slip seat 209 and bias the slips from the bottom, indirectly Cough a collection of puts against the snap ring 205 and lock bar 203, also demonstrates that the slips 50, can be pushed versus pulled, to set the slips SO without departing from the spirit of the invention.

Further modifications to the equipment and to the techniques described herein should be apparent Ford the above description of these preferred en bodirnents. Although the invention has

Gus been described in detail for a prefe:Ted embodiment, it should be understood that this explanation is for illustration, and that the invention is not limited to Me described embodiments.

Alternative equipment and operating techniques will Gus be apparent to those sldlled in Me art in view of this disclose. Modifications are thus contemplated and may be made without deponing from the Spirit of the invention, which is defined by the claims.

i,. !. ':

Claims (1)

1. - 17 74088002.361

   Claims

   5 1. A liner hanger comprising: a bodyi a plurality of slips mounted to individual seats on said body such that upon actuation of said slips load is transferred to said body from each slip through its 10 individual seat; wherein said seats are circumferentially spaced from each other creating longitudinal passages outside said body where wellbore fluids can flow.