GB2380507A - Liner hanger with plurality of slips - Google Patents

Abstract

A liner hanger comprises a body, a plurality of slips mounted to individual seats on the body, a lock, retaining the slips in a retracted position during run-in, a release mechanism, preferably including a moveable piston in a housing, where pressure moves the piston against the lock to allow the slips to set and an actuation system to set the slips after the lock has been defeated. The lock may be in the form of at least one dog held to the body by a biased sliding sleeve or a split ring held to the body by a yoke.

Description

: / / h LINER MANGER

5 The field of this invention relates to liner hangers, and' more parti. cularl,r, 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 full circumference hydraulically actuated pistons to moire the slips. These designs presented a pressure rating problem in that the full circumference piston frequently had a maximum worldling pressure si ticantly louver than the navel which it surrounded. Thus, this type of design lifted the maximum working pressure in the skin" to the rating of the cylindrical piston housing assembly. For example, it was not unusual in prior designs to have mandrels rated 5 for 12,000 PSl while the surrounding cylinder housing for the cylindrical piston to only have a rating of approximately 3,000 PSI. an effort to improve the shortcoming of this design, another design illustrated in U,S. Patent 5,417, X8 was developed. In this design Tic mandrel body received a pair of bores straddling each of the slips. A piston assembly was mounted in each of the bows vita: all of the necessary seals. The application of hydraulic pressure in We mandrel into all the piston bores 2 0 actuated the pistons on either side of each slip through acorrunon sleeve to which 1 Tic slips were attached. IPhis design, ho vevcr, vas expensive to manufacture and had many potential leak paths in me form of Me ring seals on each of the pistons wherein each slip required two pistons. This desi,however,did provide for a higher pressure rating for the liner hanger body. It also used the hydraulic pressure directly to actuate the slips. Necessarily it did not include a locidng feature 25 against premature 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

re-, re additional force to set tl e slips' essence' each application v/as designed for a pre-existing set of conditions void field variability not included as a [ea.ture of that prior art design.

Slip assemblies in the past have been configured in a variety of ways. one configuration' - when the slips are actuated, the load is passed through the slips circumferentially through their 5 guides or retainers and ar smission of the load to the underlying mandrel is avoided. In other more traditional designs, the slips are driven along tapered surfaces of a supporting cone and the loading is placed on the supporting mandrel is in a radial direction toward its center, thus tending to defonn the mandrel when setting the slips. Typical of such applications are U.S. Patents 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, obstrocl:ed Me passages that could have been used for circulating cement and mud.

The apparatus of the present invention has many objectives. A versatile actuation system for a locldug system is provided. The apparatus uses a combination of hydraulic pressure to defeat a 15 locking mechanism',v ich in turn allows mechanical actuation of the slips. The slips me configured to pass the loading into the slip seat and then into the mandrel in a manner so as not to deform the mandrel. The slips act independently of each other and transfer their load through We surrounding slip seat directly to Me mandrel. The slip seats ale attached to Tic mandrel without sveldlng 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-hole tools. Ihe slip seats are spaced from each other to provide flow charnels along the exterior of the liner hanger to facilitate the movement of cement or mud. Those passages are continued for the lend of the tool. The actuating piston assembly to defeat the lock mechanism is a bolt-on arrangement which can be readily interchanged in the field to react to changing down- hole conditions. The actuating piston is

2 5 fully compensated for thermal effects and a system is provided to vent any gases from 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 non in and liberating the dog from its groove to allow setting of the slips, which is preferably done by a plurality of springs. The pasts are also disposed in a preferred spacing to make maximum use of the limited force available MOM

tL piston assembly for releasing Me lock The lock configuration can also be in the form of a split - dug held together by a yoke which allows relative moven ent when the yoke is shined, allotting the split ring to expand. These and other objectives of the present invention will become more apparent to those skilled in the art front a review of the preferred and alternative e nbodiments described 5 belong.

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 loclc, a plurality of sptlngs actuate a sleeve which is in turn attached to the slips to move them relative to their slip seats. In an alternative embodiment:, a plu ity of spnugs can directly move We slips relative to their slip seats, when the springs released. The slip ',,eats are preferably mounted to Me mandrel without welding and have longitudinal spaces for mud or cement flow therebet veen.

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

FIGS. 1A through C are a plan View of the apparatus looking down on the spring housing, FIG. is a rotated view from the view of FIGS. PA and B showing a plan view of the lock 2 5 housing, FIG. 3 is a Section View through lines 3-3 of FI(it. 2 FIG. 4 is a section of lines 4-4 of FIG. 2; FIG. 5 is a section through lines 5-5 of FIG. 2, FIG. 6 is a section through lines 6-6 of FIG. 2;

FIG. 7A through C are a section view through the lock housing dunng the niacin position; FIG. is the section view through the piston housing in the set position when the lock has been defeated.; FIG' 9 iIlustrates the connection between the spring housing and the gage ring, 5 FIG. 10 illustrates the springs used to set the slips and the guide for each spring in sechon 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 a secuan 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 the retainer bolt to the rapture dial; location; FIG, 14 is a plan view of one of the slips; FIG. 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 new through 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 Cough Me longitudinal interior passage in We loci; housing which in pan holds Me locking dog; FIG. 22 is a plan view of the lock housing; ElG. 23 is a plan view of the slip seat; 25 FIG. 24 is a section view Trough lines 24 24 of FIG. 23; FIG. 25 is 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. 28 is a more detailed plan view of the mandrel;

BIG. 29 is section through lines 2929 of FIG. 28; FIG 30 is a section view of art 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, FIG, 32 A through C are the view of FIGS. 30 A through C rotated to show the spring 5 housings; FIGS. 33 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 furler 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 prey; FIG. 36 is a view taller along lines 36 - 36 of FIG. 31.

FIG. 36a illustrates a longitudinal cross section of the tool through the piston assembly, loclc mechanism, slip and slip seat, 15 FIG. 31 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.

}?IG. 39 is a section view of Me piston assembler and lock mechanism in the run-in position.

FIG. 40 is a 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 lhe mandrel.

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

FIG. 43 is an end view of We snap ring.

Refening to JIGS. 1 through 11, the major components of the apparatus in A will now be as described. Apparatus A her a mandrel 10 which has a lower end 12. Lower end 12 is shown schematically and those skilled in the art will appreciate that the liner Bring is connected at lower end l2. The mandrel 10 has an upper end 14 to which those sldlled in the art will appreciate is attached a running suing 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 nog 20 has a split 22 (see E1G. 3) and a draw bolt 24 so as to bung the components of the gage ring 20 together at split 22 once the gage ring 20 has been advanced beyond the shoulder 16 and onto Me reduced diameter segment 18. Gage ring 20 has several flats' one of which 26 is shown in interrupted fonn in FIG. 5 9 FIG. 9 is a section view through the gage ring 20 showing the spring housing 28 mounted to it' By comparing FIGS. 1A and 9, it can be seen that the spring housing 28 has a tab 30 which extends into a window 32 in flat 26 of gage nag 20. In that manner as shown in FIG. 9, the position of the spring housing 28 is initially fixed to the gage nng 20 and that engage nent is secured by bolts 34 FIG. 2 shows a rotated view from FIGS. 1A and B. indicating that the gage ring 20 also 10 supports the lock housing 36, The number of spnug housings 38 can vat ithout departing from the spins of the invention. In the preferred embodiment disclosed, there are three spring housings 28 and one lock housing 36, generally at 90 degree spacings, thus defining elongated passages 38 the etween(see FIG. 11), thesepassages 38 shown schematicallyinPIG. 113 allow mud or cement to pass relatively unimpeded.

15 Refemng again to FIG 2, the lock housing 36 is secured to the gage nag 20 by bolts 34 Refemug to FIG. 22, a top view of the loci; 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 shown in hidden lines is a downwardly oriented tab 44 which is placed through a corresponding opening or window in Me gage ring 20, similar to the method of attachment shovm in FIG, 1A. The lock housing 36 also has 20 an extending ann 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 the movement of receptacle 48 into a second position which reflects the setting of the slip SO. Ann 46, shown in FIG. 22 also has an oblong undercut 52 which fits into slot 54 of slip seat retainer 56 (see FIGS. 26 and 1B). that manner the slot 54 acts as a guide to the longitudinal motion of lock 2 5 housing 36. It also holds arzn 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 the spun" housing 28 shown in FIGS. 1A through C c nploying the identical undercut S2 with the same slip seat retainer 56 providing a slot 54 to guide an ann 46 which in tum 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 totaled

pit Lion from the view of FIG. 22 and therefore, it does nor show the artn 46 or receptacle 48 at the end of it which is used to connect to a slip 50. Refemng again to FIG' 22, the lock housing 3G has a series of blind 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 span" reralner 62. the run-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 companng FIGS. 7 and 8. Initially, however, each of the spring housings 28 has a plurality of blind bores 58 (see FIG. 1B)7 each of which has a spnng 60 and a retainer 62 mounted therein. The number of spungs and the size of the spnag 60 Carl vary without departing from Me spirit of We 10 invention, Those skilled in the art will appreciate that the number of available spring 60 and their size will dictate Me amount of upward force that can be exerted on gage ring so which pulls up with it the spring housing 28 and the lock housing 36, which in tom 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 shill now be described. The lock housing 36 has a 15 multi-dimensional longitudinal opening 66 (see FIG. 22). As shown in FIG. 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 dov nvvardly depending opening 7(), shown in hidden lines in FIG. 2;! and a subsequent upwardly depending opening 72. These features can be better seen in the section View of the lock housing 36 illustrated in FIG 21. FIG. 21, bore 68 is illustrated with 2 0 an opening 74 for insertion of a breakable pin 76 (see FIG. 7B). Further down bore 68 is another opening 78 fur the insertion of a guide pin 80 (see FIG 7A). Finally, the downwardly oriented openlug 10 and upwardly onented opening 72 are illustrated as well as one opening 42 for attachment to Me gage hug 20. The downwardly oriented opening 70 accepts a dog 82. Its tapered up-hole and down-hole surfaces 84 and 86 (see FIG. 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 niandrel 10 as shown in FIG. 7A, Notch 90 has tapered surfaces cc nfonning to the tapered sumacs 84 and 86 oidog 82. While 80 degrees is preferred, other angles can be used without deputing 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. the run-in position shown in FIG. 7A, the

d 82 is retained by loclc dog retainer 92. As show in FIGS. 7A and B. the lock dog retainer 92 - overlays the dog 82 holding it in the notch 90 on mandrel 10, Refening to FIG. 16 which is a top view of the lock dog retainer 92, an elo.gated slot 94 accept' the "aide pin 80 which extends through the lock housing 36, that rna,nner, 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 a receptac1e 96 shown in FIG. 16, As shown in FIGS. 19 and Or 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 modon 10 therebetween. For the run-in position, the loci; dog release 100 has a receptacle 102 (see FIGS. 19 and 20) which accepts pin 76, which in turn extends through the loci; housing 36. Thus, for run-in, the lock dog release 100 is pinned to Me lock housing 3G and has a tab 98 inserted into receptacle 96 of lock dog retainer 9Z. FIG. 16 shows the maximum down-hole position of lock dog reralner 92 due to the travel lionization of guide pin 80 extending into slot 94. In the 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 release 100 and lock dog retaper 92 occurs. The significance of the relative movement will be explained later.

Refemug to the section view of the lock dog attainer 92 (FIG. 17), it can also be seen that it has an undercut 104 which is offset from dog 82 in FIGS. 7A and B. and shifted to coincide with 2 0 dog 82 in FIG. 8. Those skilled in We an will appreciate that vhen Tic undercut 104 moves over the dog 82 the dog can be pushed out of notch PO, thus allowing an unlocldug of the lock housing 3G from the mandrel 10. As previously explained, when such unlocking of the lock mechanism L occum, the various spnogs 60 bearing on their respective retainers 62 collectively expand up hole' moving the spring housings 28 and the lock housing 36, along with gage nag 20 to which housings 2 5 28 and 36 are connected, which has the ultimate effect of pulling the slips 50 to set them.

In order to actuate the lock mechanism L to unlock and permit setting of the slips 50 a release device is required. this instance7 the release device comprises a piston housing 106 which has internal passages which are best seen in FIG. 13. massage 108 accepts a bolt 110 whose details are best shown in FIG. 12 Bolt 110 is placed over an opening 112 in the mandrel 10 The piston

L.sing 106 has a circular groove 114 Chic} accepts a sealing member, such as an O-ring 116 (see - FIG. 7B). Wi bolt 110 securing the piston housing 106 about the opening 112, thee is a sealed passage from inside the mandrel 10 through the bolt 110, through its passage 118 (see FIG. 12), Passage 118 in bolt 110 is sealingly aligned to passage 120 in piston housing 106. Passage 120 leads 5 to passage 122 within which are mounted a rupture disk 124 and a piston assembly 1:Z6 (see FIG, 7B). FIG. 7;8 shows the Neptune clink 124 adjacent the piston assembly 126 all within Me passage 122 of the piston housing 106. The purpose of We rupture disk 124 is to insure that a certain minimum pressure is achieved in the mandrel 10 before internal pressure in mandrel 10 is 10 communicated to the piston assembly 126. The piston assembly 126 has a central passage 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 the piston assembly 126 is inserted into We passage 122. Opon insertion to the position shown in FIG. 7B, the trapped fluids are displaced 15 through passage 128 until the desired position of the piston assembly 126 is reached. At that time, the cap 130 is screwed on, seating oiT the piston assembly 126 in passage 127. Pnorto installing the piston assembly 126, the rupture disk 124 is inserted The pi tDn assembly 126 is thus free to move in opposed directions to compensate for thermal cifects or other effects. AB shown in FIG. 7B, there is a space between the piston assembly 126 extending out of We piston housing 106 and the lock dog 2 rolea$e 100. This space can also be easily seen in FIG. a. loose skilled in We art will appreciate that the piston housing 106 as well as We piston assembly 126 which is in it, can be easily replaced with a different sized urns 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 bolt 110 is loosened and a different piston housing 106, having a bigger or 2 5 smallerpiston, or with a rupture disk 124 set to brealc at a dimmest value is easily insertible as a unit in replacement of e original equipment. Thus the bolt-on feature of Me piston housing 106 holding the piston assembly 126 adds versatility to the apparatus A of the present invention and allows for field changes to meet last minute changes in well operating conditions where Me apparatus A is to

be set. It also facilitates the presence of passages 38.

In order to set the slips 50, pressure must be built up sufficiently within the mandrel 10 to break the rupture disk 124. When the rapture disk 124 breaks, pressure is then applied to the piston assembly 126, moving the piston to the left as seen by comparing PIGl3. 7B and 8B. The piston assembly 126 first impacts the lock-dog release 100, pushing it up hole. As seen in FIG. 2, the lock 5 dog release 100 has downwardly oriented tab 136 adjacent to an opening 138. As shown in FIGS. 7A Liz; B. ' the lock dog release 100 is initially retained by a shear pin 76 or similar retaining devices The impact of the piston assembly 126 on Me lock-dog release 100 breaks the shear pin 76 and starts the lock-dog release 100 moving up hole. It should be noted that at this tinge there is no movement of the lock-dog retainer 92. As previously explained, the receptacle 96 of the lock-dog retainer 92 10 (see PIG. 16) is longer than the width of the tab 98 on lock-dog release 100. As a result, the energy imparted into the piston assembly 126 is initially expended solely to break the shear pin 76 without also, at the same time, having a need to overcome the Fictional resistance between the lock-dog retainer 92 and the dog 82' which it squeezes into notch 90. Those skilled in Me art will appreciate that these 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, the lock-dog retainer 92 is eventually driven up hole as shown in FIG. 8A. This places the undercut 104 (see EIG. 17) in aligrunent with dog 82, Further movement of lock-dog retainer 92 allows springs 60 to push lock housing 3G which in rum forces tapered surface 84 of dog 82 along its parallel surface in notch 90 so Mat Me dog 82 comes out of notch 90 to the final position shod in FIG. 8A. It should be noted 2 0 that as these movements are occumug, the tab 136 pushes any mud out through opening 138 in lock dog release 100. Similarly, the uphole 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 9O7 the spnag housings 28 and lock housing 36 are no longer held to the mandrel 10. At that point, Me springs 60 in the various spying housings 28 and the lack 2 5 housing 36 can push ok against their respective retainers 62, thus mooring uphold all of the spring housings 28 and lock housing 36 along with gauge nag 20. This upward movement shorn by a comparison of FIGS. 7 & 8 results in a pull upward on all of the slips 50 which drives the slips 50 outwardly into a gripping engagement with the tubular in the well bore to set the apparatus A

The method of securing the slips SO to the respective slips seat 64 will now be described.

Each of the slip seats 64 can be attached to the reduced diameter 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 affixation of the slip seat 64 to Me mandrel 5 10 in conformance with regulations that prohibit vvelding, such as those promulgated by We National Assocl ion of Corrosion Engineers (NACE), The mandrel 10 is shown in more detain in:FIGS. 27 through 29. As seen in FIG. 27, each slip seat 64 is attachable to the mandrel 10 Trough a series at = 6 of longitudinal slots 140. Each individual slot 140 is shown in greater detail in FIG. 28.

At least one opposed pair of slots, shown in FIG. 28, teas a lateral opening 142, which is designed 10 to accept a tab 144 (see FIG. 25) on the underside of the slip seat 64. The venous tabs on the underside of the slip seat 64 are aligned vvil:h the longitudinal slots 140 and more particularly, the lateral openings 142. The slots 140 have elongated undercuts 146 such that the tab 144 on the underside of me slip seat 64 Carl be first inserted into the lateral opening 142 as shown in FIG 78 and then the slip sew 64 can be moved longitudinally avid respect to mandrel 10 to put the tabs 144 15 in an offset position from lateral operating 142. This Position is shown in TRIG, 37. Also 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 150 which fits into Me 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 0 64 with respect to the mandrel 10, any load transmitted to Me slip seat 64 goes into Me mandrel 10 via transverse lug 150 and aligned lugs 144. essence, lugs 144 take a hanging load on upper ends of slots 140 and take up a racial load on the sides of slots 140 while transverse lug 150 bears on the upper end of opening 148. To finally fix the slip seat 64 to the mandrel 10, a slip seat retainer 56 is inserted through an opening 152 in the slip seat 64 and further into a notch 154 in Me mandrel 10 2 5 (see FIGS. 23 & 27). Each of the slip seat 64 are attached to Me mandrel 10 which does not defonn Me mandrel 10 in the identical manner. While a specific non-welding mode of attachment of slip sew 64 to mandrel 10 is disclosed, those skilled in the art will appreciate that other techniques for so joining those two components can be utilized without departing from the spins of the invention.

Another feature of the apparatus A of the present invention is the manner in which Me loading is transferred Mom the slip 50 to the slip seat 64 and into the mandrel 10. Each individual slip SO transfers loading to Me slip seat 64 which surrounds it, whereupon the loading through the shape of the Blip 50 is transte ed into the wall of the mandrel 10. There i8 no interaction between 5 one slip SO snd its slip sea: 64 and any other slip seat 64. The loading is transferred 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 Me mandrel 10. Referring specifically to FIGS, 23 and 14 and 15, it can be seen that: the edges 156 and 158 are preferably beveled with respect to the pliers of the paper and there is a matching slope on surfaces 160 & 163 10 of the slip seat 64. Thus, taldug into consideration the strength of the slip seat 64, the edge configuration of each slip 50 along surfaces 158 & 156 and the conforming surfaces on the slip seat 64 surfaces 160 & 162 are such that the resultant force from loading a slip 50 is a force that is merely close to tangential to the Wall which compuses the mandrel 10. In the preferred embodiment, the angle is approximately 80 decrees, putting the greatest component of force closer to:he tangential 15 direction into the wall which comprises ache mandrel 10 smith a 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 be seen in looking at FIG. 23, when the upwardpull comes to each of the slips 50, Hey are guided by surfaces 160 & 162 to move mdialIy outwardly to lock the apparatus A downhole, while at the same time, independently transtemug load from each slip co its 2 0 respective slip seat 64 Tough surfaces 160 &; 162 which are preferably at a slope of about 80 degrees resulting in the largest component of force being transferred into the mandrel 10 in a near tangential manner.

Those skilled in Me art will now appreciate that the ove-described preferred embodiment has numerous advantageous over tools in the prior an. The apparatus A employs a mechanical lock 2 5 which prevents premature settings, It uses a bolt-on piston housing 106 which allows for field

replacements to obtain different forces for disabling the mechanical lock. The rupture disk 124 requires pr determlned pressure be applied before the lock mechanism L can release. The use of a bolt-on piston housing JOG also helps reduce the profile of: the lock mechanism L and enables the provision of longitudinal passages 38 for the passage of mud and cement. The slips 50 are secured

[enlip seat 64 which are, in turn, connected to Me mandrel 10 without avenging, Each slip 50 is - configured to direct applied loads into the mandrel 10 in a direction nearly approximating the tangential or into the wall of We 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 distinguished

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

Each slip individually distributes the load applied to it to the mandrel 10 Trough the slip seat 64.

The piston assembly 126 Trough the use of cap 130 allows venting of fluids Tom passage 122 in the piston housing 106. The piston assembly 126 is free to move in both directions to react to thennal end 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 122 as opposed to its nonnal operation where an increase in pressure Awn the mandrel 10 results in breaking of the rupture Disk 124, Maximum use is made of the force generated by the piston assembly 126 through Me lost motion between the lock dog release 100 ant the lock dog retuner 92. Since rotation of Me apparatus A is possible, provisions have been made to retain Me a mh7 46 which are attached l:o Me slips 50 against centrifugal 15 force from such rotation. The slip seat retainer 56 accomplishes this function, Yet another new feature is Me drop-in arrangement for tl e slip seat 64 into the slots 140 and opening 148, 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- atressing the Slip seat 64 while at the same time efficiently communicating loads on each slip 50 into the wall which defines the mandrel 10.

2 0 Refemeg now through FIGS. 30 through 36, an altemadYe embodiment is described. As shown in FIGS. 30 Trough C, a mandrel lC0 has a series of slips 1 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 164 leads from internally of the mandrel 160 to a rupture disk 166, On the over side of the rupture disk 166 is a piston assembly 168. These components operate in the a 5 identical mariner as described for the comparable structure the preferred embodiment. Looking at rl:a. 32B, a spun" housing 170 is locket to the mandrel 160 by virtue of Me fact Rat a split ring 172 extends into a groove 174 in the mandrel 160' The split hug 172 also extends into a recess 176 in spnag housing 170. A spring 178 is shown in FIG. 32B, Those sldlled in the an will appreciate it as one of many spungs 178, each of which i' guided by a guide 180. Referring to FIG. 31, the

lo. end 187 of the spring housing 170 has a recess 184 which accepts a tab 1B6 Rich is part of the structure of the slip 162. Accordingly, the spring housing 170 is operably connected to all the slips 16% and has nu neroLts springs 178 which will drive all the slips 162 up vm1 as the spring housing 170 moves upwardly once the split ring 172 is moved out of the way. This occurs when the 5 split ring 172 is allowed to expand effectively out of groove 174 thereby no longer restraining Me spring housing 170 and thus allowing the force of all the springs 178 to move the slips 162 upwardly, Gus distributing the load on each of the slips 162 in the manner previously described for the preferred embodiment. The split nug 172 is shown in PIG. 34. It has a pair of opposed shoulders 188 & 190 which tightly squeezed together by a yoke 192 (shown in FIG. 35). Yolk 192 has a 10 pair of opposed surfaces 194 & 196 whicl1 engage surfaces 190 & 188 respectively to hold the position of the split ring 172 to a diameter sufficiently Somali so that it can effectively serve as 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 brew rupture disk 166 which in tum actuates the piston assembly 168. The piston assembly 168 engages a connecting rod 198 which iB fixedly 15 scoured to the yoke 192. SVhen the surfaces 194 & 196 on yoke 192 are displaced from the surfaces 190 at 188 on split ring 17Z, late split ring 173 can expand radially outwardly, Gus defeating the loci: of Me spring housing 170 to the mandrel 160. When this occurs, the springs 17B can bias the spring housing 170 upwardly, thus taldug up all the slips 162 and securing the apparatus while distributing the load into the mandrel 160 in Me manner previously descnbed' 2 0 Yet avower feature of the alternative embodiment can be seen from FIGS, 31 36. As shown in FIG. 36, a flow channel 200 on the back side of each slip 162 allows mud or cement flow underneath to pemut circulation of suet materials during Me normal operation of the apparatus A. This is significant in this part icular 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, 2 5 pressure in the mandrel 160 results in defeat of a lock mechanism (in this embodiment the split ring 172). The slips 162 are independently set with the spun" force from spnugs 178. Allis mode of operation is to be contrasted with Mat revealed in U.S. Patent No. 5,417,288 where the pistons actuate a ring which is directly connected to Me slips. Thus, in that design Me hydraulic pressure actually moves the slips whereas in this alternative embodiment, as well as in the preferred

e: adiment, the applied hydraulic pressure, without breaking any components other than a rupture disk such as 124 and shear pin 76, results in the release of a mecha ucal lock which allows Me independent operation of the setting of the slips So. Again, comparing to Me previous technique of U.S, PatentS,417,288, numerous passa sha reto bedrilledin the mandrel. More specifically, two 5 passages were needed for easels slip to operate it. Here7 a single passage is presented through the mandrel 160 to operate the connecting rod 198 so as to release the split ring 173 from the groove 174 thus allowing independent mechanical actuation using spun" force to set the slips 162.

Referring to FIG. 36a, one alternative embodiment of the liner hanger is composed of a mandrel 201 which has a lower end 217, The lower end is shown schematically and those skilled 10 in Me 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 skilled in Me art will appreciate, is attached to a running tool for proper positioning and securing of assembly S shown in FIGS. 36a through 38.

Refemag to FIG. 3Ga, a piston assembly 202 is secured to the mandrel 201 using a bolt 110 previously descnbed, Secured loosely by the piston assembly Z02, is a lock bar 203, which connects 15 lo the snap ring tO4, which extents 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 ring 205 through the t-slot segment 212, which is biased by Me slip 50, which is biased by the spring 60 through the spring guide 62.

Ore alternative embodiment of the piston housing 223 can best be seen in FIG. 39 in the run 2 0 in and FIG, 40 in the set position, where the end of the piston housing 223 has been extended co present cover 218 over the lock bar 203 to prevent shifting of the lock bar 203 by means over Mat the piston 126. The lock bar 203 is similar to the broke t92 in that it combines the yoke 192 and the connecting rod 198 from the previous description. The lock bar 203 has a pair of opposed surfaces

at, & 2ao (FIG. 42) which hold the opposed shoulders 212 222 (FIG. 43) respectively of Me 2 5 snap nug 204 and secure Me snap hug 204 in the recess 205 in the mandrel 201. Tbis method demonstrates that the snap nug 204 can be restrained from the top or the bottom Bailout departing frown:he spirit of the invention.

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

The Iternative 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 Trough a collection of pads, against the snap ring 205 and lock bar 203, also demonstrates that the slips SO, can be pushed versus pulled, to set the slips SO without departing from the spoil: of the invention.

Father modifications to the equipment and to the techniques described herein should be apparent from the above description of these preferred embodiments. Although the invention has

thus been described in detail for a preferred embodiment, it should be understood that this explanation is for illustration, and that the invention is not lifted to the described embodiments.

AItemadve equipment and operating techniques will thus be apparent to those skilled in Me art in view of this disclosure. Modifications are thus contemplated and may be made without departing

from the spins of the invention, which is defined by the clumsy

Claims (11)

1. Claims

   5 1. A liner hanger comprising: a body; 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; a lock to retain said slips in a retracted position for run in; and a release mechanism removably mounted to an exterior surface of said body for selective contact with 15 said lock to allow said slips to set.
2. 2. The hanger of claim 1, further comprising: an actuation assembly on said body which selectively applies a force to set said slips after said 20 lock has been defeated by movement of said release mechanism.
3. 3. The hanger of claim 2, wherein: said release mechanism comprises a housing having a 25 passage which communicates with an opening in said body and a movable piston in said housing; whereupon, pressure from said body into said housing moves said piston against said lock to allow said actuation assembly to set said slips.
4. 4. The hanger of claim 3, wherein: said housing is retained by a fastener which is inserted into the opening in said body and has a passage therethrough to allow fluid communication to said 35 piston.
5. 5. The hanger of claim 3, wherein:

   - 18 said piston is free to move in said housing to compensate for thermal effects from surrounding wellbore fluids. 5
6. 6. The hanger of claim 1, wherein: said lock comprises at least one dog retained to said body by a biased sliding sleeve assembly, said sliding sleeve assembly comprises a plurality of components connected to each other to provide for 10 initial relative movement followed by tandem movement when contacted by said release mechanism to release said dog from said body.
7. 7. The hanger of claim 6, wherein: 15 a first component of said sliding sleeve assembly which is initially contacted by said release mechanism is initially secured to said body; whereupon contact of said first component by said release mechanism said secured connection to said body 20 is disconnected while leaving a second component of said sliding sleeve assembly initially undisturbed.
8. 8. The hanger of claim 7, wherein: said body comprises a plurality of openings and 25 each seat comprises tabs to enter respective openings whereupon relative longitudinal movement between said seat and said body moves said seat to a secure position where said seat cannot move away from said body.

   30
9. 9. The hanger of claim 1, wherein: said lock comprises a biased sleeve held to said body by a split ring held together by a yoke, whereupon when said yoke is displaced by said release mechanism said split ring expands to release said sleeve to be 35 biased which in turn moves said slips to a set position.
10. 10. The hanger of claim 3, further comprising:

    - 19 a removable member in said housing which is responsive to applied pressure from said body to ensure pressure buildup to a predetermined level prior to communicating said pressure to said piston.
11. 11. The hanger of claim 1, wherein: said lock comprises a split ring which is held by a yoke to said body, to retain said slips against a bias force, 10 said release mechanism moving said yoke to allow said bias force to set said slips.