Bottom lock pipe seal assembly

A seal assembly is disclosed including first and second annular members mutually movable longitudinally to effect a first configuration in which the seal assembly is releasably anchored to a cylindrical body circumscribed by the seal assembly, and a second configuration in which the seal assembly is releasably anchored to a surrounding conduit. Sealing members are carried by the seal assembly to engage the enclosed cylindrical body as well as the circumscribing conduit. Operation of the seal assembly for movement between the first and second configurations is accomplished by manipulation of the cylindrical body which, with the seal assembly anchored to the conduit, is permitted limited longitudinal movement relative to the conduit and seal assembly while maintaining sealing engagement with the seal assembly. A disclosed embodiment includes a well seal assembly, or packer, for sealing a pipe string to a well conduit.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to techniques for sealing cylindrical bodies 
to circumscribing conduits. More particularly, the present invention 
relates to seal assemblies for positioning within, and anchoring to, the 
interiors of conduits, and finds particular application to apparatus and 
methods for sealing pipe strings to conduits within wells. 
2. Description of Prior Art 
Sealing apparatus of various kinds are used in several well working 
operations, and in the production of a well. For example, in downhole 
cementing procedures, seal assemblies are used to control the placement of 
cement and the maintenance of pressure to accomplish cementing operations. 
Seal assemblies in the form of packers are known for isolating formations 
for treatment, or for isolating segments of liner or casing for squeeze 
cementing, for example. Packers are routinely used for sealing production 
strings to liner or casing to define flow paths from producing formations 
to the surface. Several packers may be utilized to isolate various 
formations in a multi-zone producing well. Polished bore receptacles are 
used in conjunction with annular seal members to provide sliding seals. 
Particularly in the case of packers, the seal assembly is usually 
positioned within a well by means of a pipe string, and then set in 
sealing and anchoring engagement with the surrounding conduit. The pipe 
string may be released from anchoring engagement with the packer, and be 
movable in the well without disturbing the setting of the packer in 
engagement with the well conduit. The setting operation usually involves 
the movement of multiple components of the packer to expand one or more 
resilient seal members, and to wedge anchoring slips against the 
surrounding well conduit. These operations are controlled from the 
surface, and may be effected either by manipulation of the pipe string 
used to carry the packer into the well, or by application of hydraulic 
pressure through the pipe string to the packer. Retrievable packers are 
known, and may be released from the well conduit by one or more operations 
carried out with the pipe string. 
Inflatable packers are known for use in unlined wells. In the case of 
production packers, the seal assemblies used to isolate formations and 
define flow paths to the surface are set within well casing or liner, 
which is usually made up to include a sequence of tubular members threaded 
together or joined by collars. 
SUMMARY OF THE INVENTION 
Apparatus according to the present includes first and second members 
mutually movable generally longitudinally between a first configuration, 
in which the members are releasably latched to a cylindrical body, and a 
second configuration in which the members are released from latching 
configuration with the cylindrical body and are releasably latched to a 
conduit or tubular body generally circumscribing the members and the 
cylindrical body. The first and second members include a first latch 
mechanism by which the members are latched to the cylindrical body in the 
first configuration. A second latch mechanism as part of the first and 
second members latches the members to the conduit in the second 
configuration. The first and second members may be positioned within the 
conduit by means of the cylindrical body, to which the members are latched 
in the first configuration. Manipulation of the cylindrical body may then 
be used to operate the first and second members to move them to the second 
configuration, in anchoring engagement with the conduit and released from 
anchoring engagement with the cylinder. Further movement of the cylinder 
may operate the first and second members to latch the members to the 
cylinder, and release them from latching engagement with the conduit. A 
detent included with the conduit may engage and hold the first member 
against axial movement to permit the second member to be moved 
longitudinally relative to the first member by means of longitudinal 
movement of the cylinder relative to the conduit to move the members from 
the first configuration to the second configuration. 
A seal mechanism is carried by one or both of the first and second members 
to sealingly engage an exterior, annular seating surface included in the 
cylindrical body. The sealing mechanism also sealingly engages an 
interior, annular seating surface included in the conduit, when the first 
and second members are releasably latched to the conduit. In the latter 
case, the cylindrical member may be moved longitudinally relative to both 
the conduit and the first and second members latched and sealed thereto, 
while maintaining the sealing engagement between the cylindrical body 
seating surface and the sealing mechanism. 
Each of the first and second latching mechanisms may include a plurality of 
latching dogs radially movable between latching configurations with the 
respective cylindrical or conduit body, and release configurations. First 
and second surfaces cooperate with the first and second latching mechanism 
dogs, respectively, to maintain the dogs in latching configuration, 
radially contracted in the case of the first latching mechanism, and 
radially extended in the case of the second latching mechanism. Profiles 
are provided in the exterior surface of the cylindrical member and the 
interior surface of the conduit to receive the first and second latching 
mechanism dogs, respectively. 
A third latching mechnism is included in the first and second members to 
releasably and selectively maintain the members in the first and second 
configurations. The third mechanism may include a plurality of latching 
dogs as part of one of the first and second members, and a pair of 
profiles as part of the other of the two members. The latching dogs are 
resiliently mounted to be engaged in one of the profiles in the first 
configuration of the first and second members, and to be engaged in the 
other of the two profiles in the second configuration. A frangible 
mechanism such as one or more shear screws or pins may connect the first 
and second members in the first configuration to preserve that 
configuration until the members are selectively moved to the second 
configuration. With the first and second members in the second 
configuration, a stop mechanism included in the members prevents further 
mutual longitudinal movement between the members beyond the second 
configuration. 
The second body may include a collet assembly, wherein the first latching 
mechanism dogs are mounted on the ends of collet fingers for radial 
movement. The third latching mechanism dogs may be carried on a plurality 
of collet ribs for radial movement. The second latching mechanism dogs may 
be mounted for radial movement in apertures in the first member. 
In an embodiment described and illustrated, the present invention includes 
a seal assembly releasably latchable to a pipe string for positioning and 
setting within a well conduit. A polished annular seating surface carried 
by the pipe string may be of any length desired to accommodate limited 
movement of the pipe string with the seal assembly anchored to the well 
conduit while maintaining sealing engagement between the seal assembly and 
the pipe string. Such pipe string movement may be employed in various 
procedures in operating on the well, or may result from thermal expansion 
of the pipe string, for example. Longitudinal movement of the pipe string 
relative to the seal assembly latched to the well conduit may latch the 
seal assembly to the pipe string and release the seal assembly from 
anchoring to the well conduit so that the seal assembly may be maneuvered 
relative to the well conduit, and retrieved from the well with the pipe 
string. 
In a method of the invention, a cylindrical body is sealed to a conduit by 
use of an annular seal assembly circumscribing the cylindrical body in 
sealing and releasable anchoring engagement. The cylindrical body is 
maneuvered within the conduit to engage the seal assembly with a stop 
fixed relative to the conduit, and to sealingly engage the seal assembly 
with the conduit. Movement of the cylindrical member longitudinally 
relative to the conduit releases the seal assembly from anchoring 
engagement with the cylinder and releasably anchors the seal assembly to 
the conduit. A method of sealing a pipe string in a well conduit is 
disclosed, in which a seal assembly is sealed and releasably anchored to 
the pipe string. The pipe string is lowered into the well conduit to a 
location where the seal assembly engages a stop provided with the conduit, 
and sealingly engages the conduit. Further lowering of the pipe string 
relative to the well conduit operates the seal assembly to release the 
seal assembly from anchoring with the pipe string and to anchor the seal 
assembly to the conduit. The seal between the pipe string and the conduit 
is maintained though the pipe string may be moved longitudinally relative 
to the conduit and seal assembly. The seal assembly may be operated by 
raising of the pipe string to anchor the seal assembly to the pipe string 
and to release the seal assembly from anchoring engagement with the well 
conduit, thereby permitting the seal assembly to be retrieved from the 
well conduit with the pipe string. 
The present invention provides a retrievable well packer including a first 
latch mechanism for releasably latching the packer to a pipe string 
whereby the packer may be manipulated within a well conduit, and a second 
latch mechanism for releasably anchoring the packer to the conduit. The 
operations of the first and second latch mechanisms are interconnected so 
that when one of the latch mechanisms is in anchoring configuration the 
other latch mechanism is in release configuration, and at all times one or 
the other of the latch mechanisms is in anchoring configuration. A detent 
mechanism maintains the packer in either the first or the second 
configuration in which the first or second, respectively, latch mechanism 
is in anchoring configuration. The packer carries sealing apparatus for 
sealingly engaging an exterior seating surface of the pipe string and for 
sealingly engaging an interior seating surface of the conduit. A second 
detent mechanism limits longitudinal movement of the packer along the well 
conduit whereby the packer may be positioned within the conduit to effect 
operation of the second detent mechanism by longitudinal movement of the 
pipe string to anchor the packer to the well conduit in the second 
configuration. The pipe string is permitted at least limited longitudinal 
movement with the packer anchored to the conduit and sealing the conduit 
to the pipe string. The packer may be released from anchoring engagement 
with the conduit and reanchored to the pipe string by longitudinal 
movement of the pipe string. 
A well packer according to the present invention may be anchored to a well 
conduit utilizing a profile provided in the conduit for receiving latching 
dogs. With the packer disengaged from anchoring with the pipe string used 
to position and operate the packer, the pipe string may be moved at least 
a limited longitudinal distance relative to the packer and conduit while 
maintaining the seal provided by the packer between the pipe string and 
the conduit.

DESCRIPTION OF PREFERRED EMBODIMENTS 
A well packer or seal apparatus according to the present invention is shown 
generally at 10 in FIGS. 1A and 1B combined, in running in configuration 
supported by a pipe string 12. The pipe string includes a pipe segment in 
the form of a polished nipple 14. A sub 16 is threadedly engaged to the 
bottom of the nipple 14 and carries an assembly of centralizers 18 for 
guiding the pipe string 12. 
The seal assembly 10 includes a first, or outer, annular member shown 
generally at 20 and a second, or inner, annular member shown generally at 
22. 
The first member 20 carries a first, or interior, annular sealing assembly 
shown generally at 24, and a second, or exterior, annular sealing assembly 
shown generally at 26. The first member 20 further includes an annular 
seal body 28 having an interior, elongate annular recess 30 opening toward 
the top of the seal body, and an external, elongate annular recess 32 
opening toward the bottom of the seal body. The interior sealing assembly 
24 is mounted on the seal body 28 within the interior recess 30 and held 
in place by a retainer ring 34 threaded to the top end of the seal body. 
The exterior sealing assembly 26 is mounted on the seal body 28 within the 
exterior recess 32 and held in place by a latch body 36 threaded to the 
bottom end of the seal body. 
The interior sealing assembly 24 is construced to provide sliding, sealing 
engagement between the seal body 28 and the polished exterior surface of 
the nipple 14. Two arrays of resilient, annular seal members 38 and 40 are 
buttressed at their respective longitudinal ends by packing headers 42, 
and further separated by a two-part, split ring 44. Each of the 
semi-circular ring halves has a L-shaped cross section, and lies within an 
appropriate annular grooves 46 within the recess 30. A cover ring 48 
having a complementary L-shaped cross section overlies and maintains in 
position the split ring 44. The positioning, size and construction of the 
elements included in the interior sealing assembly 24 are such that, with 
the retainer ring 34 threaded in place, the arrays of seal members 38 and 
40 extend sufficiently radially to be compressed between the surface of 
the seal body 28 within the recess 30 and the exterior surface of the 
polished nipple 14 to provide a slidable, fluid-tight seal between the 
first member 20 and the nipple. The seal members of the arrays 38 and 40 
may be chevron-type seal elements, for example, or any type seal elements 
capable of providing the sliding, sealing engagement described. 
The construction and arrangement of the exterior sealing assembly 26 are 
similar to those of the interior sealing assembly 24. Two arrays 50 and 52 
of resilient, annular seal members, buttressed by packing headers 54, are 
separated by an assembly including a two-part split ring 56 of L-shaped 
cross section maintained within an annular groove 58 by a cover ring 60 of 
complementary L-shaped cross section, with the seal elements of the arrays 
50 and 52 maintained, with the aid of the latch body 36, to provide a 
slidable, fluid-tight seal between the surface of the seal body 28 within 
the recess 32 and a polished seating surface 62 on the interior of a 
circumscribing well conduit segment 64. 
The second seal apparatus member 22 is constructed in the form of a collet 
assembly. A plurality of longitudinally oriented collet ribs 66 extend 
between a top base collar 68 and a lower ring 70. Midway its length, each 
rib 66 carries a radially outwardly extending protrusion 72, beveled at 
its upper and lower limits, to serve as a latch dog. A plurality of collet 
fingers 74 extends downwardly from the ring 70. Each collet finger 74 ends 
in an enlarged portion 76, extend radially inwardly and outwardly, 
generally beveled at its upper and lower extremities as shown in FIG. 1B, 
and serving also as a latch dog. It will be appreciated that the latch 
dogs 72 and 76 are generally movable radially inwardly and outwardly with 
the deformation and relaxation of the collet ribs 66 and collet fingers 
74, respectively. In the disposition illustrated in FIG. 1B, the collet 
ribs 66 and collet finbers 74 may be in their respective relaxed states. 
The latch body 36 generally encloses the second member 22, and, in the 
running in configuration of FIGS. 1A-1B, is locked to the second member by 
one or more shear screws or pins 78. The shear screws 78 serve as a 
frangible mechanism for maintaining the relative longitudinal positions of 
the first and second members 20 and 22, respectively, until the members 
are to be selectively moved to another configuration, as described in 
further detail hereinafter. 
The interior surface of the latch body 36 is broken by first and second 
annular grooves or profiles 80 and 82, respectively, mutually axially 
displaced to receive the latch dogs 72. The dogs 72 reside in the first 
profile 80 with the second member positioned relative to the latch body as 
illustrated in FIG. 1B, and reside in the second profile 82 with the 
second member in a second configuration (FIG. 2) as described hereinafter. 
Both of the latch body grooves 80 and 82 have beveled sides to facilitate 
movement of the beveled latch dogs 72 into and out of the profiles as 
selected. 
Below the second profile 82 the interior surface of the latch body 36 
features a downwardly-facing, annular shoulder 84 which, in the running in 
configuration of FIG. 1B, abuts the upper exterior annular edge 86 of the 
collet ring 70. The lower interior annular edge 88 of the collet ring 70 
is, in the configuration of FIG. 1B, in abutment with the top annular 
surface 90 of the centralized sub 16. 
The latch body is further broken by four apertures 92 symmetrically 
positioned about the circumference of the latch body. A latching dog 94 is 
mounted for radial movement within each of the apertures 92. As shown in 
FIG. 5, each of the four latch dogs 94 has beveled arcuate edges and a 
circumferentially extending flange 96 protruding from each end of the dog 
at the radial inner extent of the dog. The four latch dogs 94 are mounted 
within the symmetrically spaced apertures 92 with the flanges 96 
overlapping the circumferential peripheries of the apertures to prevent 
the latch dogs from falling radially outwardly from the latch body 36. The 
disposition of the latch bodies 94 in the running in configuration of FIG. 
1B may be further appreciated by reference to FIG. 3. The interior surface 
62 of the well conduit 64 is broken by an annular groove or profile 98 for 
receiving the latch dogs 94. In the configuration of FIG. 1B the collet 
ribs 66 between the base collar 68 and the rib-mounted latch dogs 72 are 
positioned radially within the locations of the latch dogs 94. The radial 
extension of the ribs 66 in the instant configuration is insufficient to 
force the latch dogs 94 radially beyond the outer surface of the latch 
body 36. Consequently, in the configuration of FIG. 1B with the collet 
ribs 66 in registration with the latch dogs 94, the later are not 
propelled into the conduit profile 98. 
The outer annular surface 100 of the base collar 68 is of greater diameter 
than the radial extension of the collet ribs 66 in the configuration of 
FIG. 1B. In the configuration illustrated in FIGS. 2 and 4 are discussed 
in detail hereinafter, the base collar 68 is in registration with the 
latch body dogs 94 so that the collar outer surface 100 forces the dogs 94 
to protrude radially outwardly through the apertures 92 and into the 
conduit profile 98, the outward radial movement by the dogs 94 being 
limited by engagement of the flanges 96 with the inner surface of the 
latch body 36 as noted hereinbefore (FIG. 4). Beveling of the sides of the 
conduit groove 98 faciliates the movement of the beveled latch body dogs 
94 into and out of the profile in the operation further described 
hereinafter. 
Aobve the centralizers 18 the sub 16 features on its outer surface a 
beveled, annular groove or profile 102 for receiving the latch dogs 76 
mounted on the collet fingers 74. The interior surface of the latch body 
36 is further structured to manipulate the latch dogs 76. The latch body 
interior surface 104 toward the bottom of the latch body 36 is of 
sufficiently small interior diameter that the surface 104, when in 
registration with the latch dogs 76, maintains the latch dogs residing 
within the sub groove 102 as shown in FIG. 1B. An annular interior surface 
segment 106 of the latch body 36, extending below the lower limit of the 
surface 104 and connected thereto by a frustoconical, downwardly-facing 
surface bevel 108, is of sufficiently large internal diameter to permit 
the latch dogs 76 to be moved radially outwardly out of the sub groove 
102, as illustrated in FIG. 2, for example, The beveled surface of the 
groove 102 facilitates movement of the latch dogs 76 into and out of the 
groove. In the configuration of FIG. 2, the beveled latch body surface 108 
may receive the top bevel of the outer surface of the latch dog 76, with 
the larger interior diameter surface 106 accommodating the radial depth of 
the latch dogs as shown. 
One or more lugs 110 are carried by the latch body 36, mounted in 
appropriate apertures through the wall of the latch body and extending 
radially inwardly beyond the inner surface of the latch body. In the 
configuration of FIG. 2, the lugs 110 abut the lower exterior annular edge 
112 of the collet ring 70 as a stop against further longitudinal movement 
of the second member 22 downwardly relative to the first member 20. During 
assembly of the apparatus, the lugs 110 may be fixed in place relative to 
the latch body 36 after the second member 22 is positioned within the 
latch body. 
The interior seating surface 62 of the well conduit 64 is defined at the 
upper end of the seating surface by an upwardly-facing, frustoconical 
shoulder 114 acting as a stop, or detent, to limit the downward 
longitudinal movement of the first member 20 of seal assembly 10 by 
engaging a generally complementary, downwardly-facing, frustoconical 
shoulder 116 included as part of the seal body 28. 
The well conduit 64 may be provided by any type of tubing previously 
positioned within a well in which the seal assembly 10 is to be utilized. 
A profile, such as the groove 98, for receiving the latching dogs 94, and 
a detent, such as the shoulder 114, with a seating surface such as 62 
positioned between the detent and profile are all that is required of the 
well conduit to receive and be sealed by the seal assembly 10. As 
illustrated, the well conduit 64 may be included in a well liner assembly, 
which may extend downwardly from the conduit 64 as indicated in phantom by 
the liner segment 117. If such is the case, for example, the conduit 64 
may be located at or near the top of the liner assembly cemented in place 
in the well. For example, the conduit 64 may extend upwardly to include a 
Jay-slot 118, and may be backed by a tie-back sleeve 120 welded to the 
exterior of the conduit to cover the Jay-slot. The liner assembly 
including the conduit 64 may have been previously positioned within the 
well for cementing purposes by a pipe string connected to the assembly by 
means of a pair of Jay-pins (not shown) residing in the Jay-slots 118, and 
fixed to the tie-back sleeve 20 and conduit 64 by a pair of shear screws 
122. In the operation of setting the liner assembly in the well, the shear 
screws 122 are broken to accommodate manipulation of the pipe string 
relative to the liner assembly and the Jay-slots 118 to set a liner 
hanger, for example. Regardless of the nature of the well conduit to which 
the seal assembly 10 is to be engaged, the detent (shoulder 114) and 
profile (groove 98) may be provided as illustrated, or in any other 
suitable manner such as by tubular member end surfaces joined at collar 
joints, for example. The application of the well seal assembly as 
illustrated is not limited to the nature of the well conduit. 
To utilize the seal assembly 10 to provide a seal between a pipe string 12 
and a well conduit 64, the seal assembly is mounted on the polished nipple 
14 in the first configuration illustrated in FIGS. 1A and 1B. The interior 
sealing assembly 24 sealingly engages the outer seating surface of the 
polished nipple 14. The second member 22 is positioned within the first 
member 20 with the collet dogs 72 mounted on the collet ribs 66 received 
within the first latch body profile 80. In this first configuration of the 
first and second members the base collar 68 of the second member 22 is 
axially disposed from the latch body dogs 94, and the latch dogs 76 
positioned at the ends of the collet fingers 74 are within the latch body 
surface 104. The collet-finger mounted dogs 76 are thus maintained within 
the centralizer sub groove 102, latching the seal assembly 10 to the sub 
and the pipe string nipple 14. The shear pins 78 connect the first and 
second members 20 and 22, respectively, to maintain this first 
configuration. 
As the pipe string 12 is made up at the surface, the sub 16 and the 
polished nipple 14, with the seal assembly 10 mounted thereon in 
releasable engagement by means of the latch dogs 76 and sealed to the 
nipple by the interior sealing assembly 24, are lowered within the well 
conduit until the seal assembly shoulder 116 engages the shoulder 114 on 
the well conduit segment 64. Further downward movement of the first seal 
assembly member 20 is thus prevented. If the pipe string 12 is moved 
longitudinally downwardly within the conduit 64 with the shoulders 114 and 
116 in abutting engagement, the shear screws 78 must be broken to permit 
the second member 22, which is held to the sub 16 by the latch dogs 76, to 
move with the pipe string. However, the shear screws 78 may be of 
sufficient shear strength that the well operator may detect the engagement 
of the shoulders 114 and 116 without breaking the shear screws. The 
operator may then raise the pipe string to measure a pipe string stroke to 
be utilized in further operations on the well, for example. 
To set the seal assembly 10 within the well conduit 64, the operator lowers 
the pipe string 12 to engage the shoulders 114 and 116. At that point, the 
exterior sealing assembly 26 is within the longitudinal extent of the well 
conduit polished interior surface 62 to seal the seal assembly 10 to the 
conduit 64. Also, the latch body dogs 94 are in registration with the well 
conduit profile 98. Then, further movement of the pipe string 12 
downwardly relative to the well conduit 64 will pull the second member 22 
downwardly relative to the first member 20, breaking the shear screws 78 
and causing the collet-rib mounted latch dogs 72 to ride out of the first 
latch body profile 80. The radially inward movement of the latch dogs 72 
required to move the dogs out of the groove 80 causes the collet ribs 66 
to flex radially inwardly, the relative diameters of the components 
including the outer surface of the nipple 14 accommodating such radial 
flexing. 
The downward movement of the second member 22 with the pipe string 12 
continues until the latch dogs 76, residing in the groove 102, are pulled 
downwardly beyond the lower limit of the latch body interior surface 104. 
The latch dogs 76 are then in registration with the larger internal 
diameter latch body surface 106 and the beveled surface 108, and may move 
out of the sub profile 102 as illustrated in FIG. 2. The collet-rib 
mounted latch dogs 72 are placed in registration with, and moved into, the 
second, lower profile 82 of the latch body 86. The action of the collet 
ribs 66 drives the latch dogs 72 into the second profile 82 and maintains 
them in the profile to releasably latch the seal assembly 10 in the second 
configuration of FIG. 2. Also, the lower outer edge 112 of the collet ring 
70 is in abutting engagement with the lugs 110. 
As the second body 22 is moved to the second configuration illustrated in 
FIG. 2, the collet base collar 68 is drawn downwardly into registration 
with the latch body dogs 94, the lower beveled surface of the collar and 
the upper interior beveled surface of the dogs 94 facilitating such 
movement. The exterior surface 100 of the collar 68 thus engages the 
interior surfaces of the dogs 94, moving the dogs radially outwardly into 
the well conduit profile 98 and maintaining the dogs therein in latching 
engagement with the well conduit 64. 
The manipulation of the seal assembly 10 from the first configuration of 
FIGS. 1A and 1B to the second configuration of FIG. 2 is accomplished by 
the downward movement of the pipe string 12 relative to the well conduit 
64. In that operation, the seal assembly 10 is released from latching 
engagement with the pipe string 12 as the collet latch dogs 76 are 
permitted to move radially outwardly relative to the sub profile 102, and 
the seal assembly is releasably latched to the well conduit 64 as the 
latch body dogs 94 are forced into the well conduit profile 98. 
Furthermore, the first and second seal assembly members 20 and 22, 
respectively, are releasably latched in the second configuration by the 
collet latch dogs 72 being maintained within the second latch body profile 
82 by the collet ribs 66 maintaining the relaxed state. Additionally, the 
second body 22 is prevented from further downward movement relative to the 
first body 20 from the second configuration of FIG. 2 by the engagement of 
the collet ring edge 112 with the lugs 110. 
During the entire setting operation, the seal assembly 10 maintaines 
sealing engagement with both the pipe string 12, by means of the interior 
sealing mechanism 24, and the well conduit 64, by means of the exterior 
sealing mechanism 26. Furthermore, with the pipe string 12 released from 
latching engagement with the seal assembly 10, the pipe string may be 
moved, to the extent of the polished nipple 14, longitudinally downwardly 
and, to a limited extent, upwardly relative to the seal assembly and the 
well conduit 64 to which the seal assembly is fixed. Such movement by the 
pipe string 12 maintains the sealing engagement between the seal assembly 
10 and the pipe string as long as the polished exterior seating surface of 
the landing nipple 14 is in engagement with the interior sealing assembly 
24. Additionally, the sealing engagement effected between the sealing 
mechanism 24 and the polished nipple 14, as well as the sealing engagement 
effected between the exterior sealing assembly 26 and the polished surface 
62 of the well conduit 64, is maintained in the presence of sliding 
between the seal assembly and the respective surfaces. The ability of the 
collet fingers 74 to be deformed accommodates the latch dogs 76 riding 
over the exterior surface of the sub 16 as shown in FIG. 2. The beveling 
of the interior surfaces of the dogs 76 and that of the sub exterior 
surface facilitates movement of the dogs 76 over the top end of the sub as 
well as in and out of the profile 102. Consequently, the pipe string 12 
may be manipulated longitudinally relative to the well conduit 64 to carry 
out various well working operations, for example, while maintaining the 
pipe string sealed to the well conduit. Additionally, thermal expansion of 
the pipe string 12, accompanied by downward movement of the nipple 14 
relative to the seal assembly 10 anchored to the well conduit 64, will not 
interfere with the integrity of the sealing between the pipe string and 
the well conduit as provided by the seal assembly. 
The seal assembly 10 may be released from anchoring engagement with the 
well coduit 64 and releasably latched to the pipe string 12 by sufficient 
upward movement of the pipe string relative to the well conduit. As the 
pipe string 12 is raised, the sub profile 102 is brought into registration 
with the collet latch dogs 76, still residing in registration with the 
large-diameter latch body surface 106. The latch dogs 76 are thus 
permitted to move within the groove 102 upon relaxation of the collet 
fingers 74. The top surface 90 of the centralizer sub 16 is brought into 
abutting engagement with the collet ring surface 88 (FIG. 1B), so that 
further upward movement by the pipe string 12 drives the collet ring 70 
and, therefore, the second member 22 upwardly relative to the well conduit 
64. The first member 20 remains longitudinally fixed relative to the 
conduit 64 as long as the latch body dogs 94 are maintained within the 
conduit profile 98 by the collet base collar surface 100. With the upward 
movement of the second member 22 relative to the first member 20, the 
collet latch dogs 72 are forced out of the second latch body profile 82, 
again flexing the collet ribs 66 radially inwardly. The sub 16 continues 
to move the second body 22 upwardly relative to the well conduit 64, 
driving the base collar 68 upwardly relative to the latch body dogs 94. 
When the second member 22 has been moved to bring the collet latch dogs 72 
into registration with the first latch body profile 80, the collet ribs 66 
move the dogs 72 into the profile 80 and maintain the dogs therein to 
latch the first and second members 20 and 22, respectively, in the first 
configuration of FIGS. 1A and 1B. The outer surface 100 of the base collar 
68 is clear of the latch body dogs 94 in that configuration, and the dogs 
94 are permitted to move radially inwardly, being in registration with the 
collet ribs 66 of lesser outer diameter than the collar surface 100. 
As the second member 22 is moved into the first configuration of FIGS. 1A 
and 1B relative to the first member 20, the collet latch dogs 76 are moved 
into registration with the smaller internal diameter latch body surface 
104, which maintains the latch dogs 76 in the sub profile 102 in 
releasable latching engagement with the pipe string 12. The seal assembly 
10 is thus released from anchoring engagement with the conduit 64, and is 
anchored to the pipe string 12. 
With the seal assembly 10 in the first configuration of FIGS. 1A and 1B, 
the collet ring edge 86 abuts the latch body shoulders 84 to prevent 
further upward movement of the second member 22 relative to the first 
member 20. Consequently, further upward movement of the pipe string 12, to 
which the second member 22 is releasably anchored by the latch dogs 76 
being held in the sub profile 102, raises both the second member and the 
first member 20, the two members being releasably latched together also by 
the latch dogs 72 being maintained by the collet ribs 66 in the first 
latch body profile 80. The seal assembly 10 may then be moved 
longitudinally relative to the well conduit 64, and may be retrieved from 
the well with the pipe string 12. Alternatively, the seal assembly may be 
again lowered on the pipe string 12 to be set in sealing and anchoring 
engagement with the well conduit 64, the setting and releasing operations 
being carried out an indefinite number of times as selected. 
The present invention has a wide range of applications. Further, the seal 
assembly construction of the present invention is relatively inexpensive 
to accomplish, particularly when compared with conventional packers. 
Additionally, the construction and operation of the seal assembly may be 
varied to accommodate the application, or for convenience. For example, 
any number of latching dogs may be utilized to releasably anchor the seal 
assembly in the different configurations, and to the pipe string and the 
well conduit. The construction of the dogs, and their manner of anchoring 
or gripping may also be varied. 
Among the many applications of the present invention is the use of a seal 
assembly so constructed and operated as a production packer, for example. 
The well conduit to which the seal assembly is anchored and sealed in the 
well may be lining or casing cemented in place. The pipe string used to 
position and operate the seal assembly may be a production pipe string so 
that, once the seal assembly is located within and anchored and sealed to 
the well conduit, the same pipe string may be retained in the well and 
used to accommodate fluid flow to the surface. 
The foregoing disclosure and description of the invention is illustrative 
and explanatory thereof, and various changes in the method steps as well 
as in the details of the illustrated apparatus may be made within the 
scope of the appended claims without departing from the spirit of the 
invention.