U.S. patent number 3,842,914 [Application Number 05/359,753] was granted by the patent office on 1974-10-22 for safety joint method and apparatus.
This patent grant is currently assigned to Hydril Company. Invention is credited to James D. Mott.
United States Patent |
3,842,914 |
Mott |
October 22, 1974 |
SAFETY JOINT METHOD AND APPARATUS
Abstract
A method and apparatus for a subsurface safety joint connectable
in a well conduit to effect positive separation of the well conduit
when such separation is desired. The safety joint release is
effected alternatingly by a predetermined fluid pressure in the
bore of the well conduit or by rotation of a portion of the well
conduit.
Inventors: |
Mott; James D. (Houston,
TX) |
Assignee: |
Hydril Company (Houston,
TX)
|
Family
ID: |
23415136 |
Appl.
No.: |
05/359,753 |
Filed: |
May 14, 1973 |
Current U.S.
Class: |
166/377; 285/34;
175/320; 285/922 |
Current CPC
Class: |
E21B
17/06 (20130101); Y10S 285/922 (20130101) |
Current International
Class: |
E21B
17/06 (20060101); E21B 17/02 (20060101); E21b
043/00 (); E21c 015/00 () |
Field of
Search: |
;166/315 ;175/320
;285/3,18,33,34,DIG.23,DIG.24 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Attorney, Agent or Firm: Pravel & Wilson
Claims
What is claimed is:
1. A safety joint for well conduits, including:
a. a first tubular member having a bore therethrough adapted for
connection at a first end to a well conduit and having a surface
with a locking recess formed therein;
b. a second tubular member having a bore therethrough adapted for
connection at a first end to another section of the well conduit
with said bores of said first tubular member and said second
tubular member communicating therebetween;
c. lug means mounted with said second tubular member for movement
relative to said second tubular member to an engaging position
within said locking recess for connecting said first and said
second tubular members and to a free position spaced from said
locking recess enabling separation of said first and said second
tubular member;
d. piston means operably connected with said lug means for movement
to a locking position to retain said lug means in said locking
recess and to a release position enabling said lug means to move to
said free position, said piston means moving to the release
position when a predetermined pressure urges thereon; and
e. means operably engaging said lug means for effecting release of
said lug means from said locking recess when said first and said
second tubular members are rotated relative to each other wherein
the safety joint is releasable by relative rotation or the urging
of a predetermined fluid pressure.
2. The apparatus as set forth in claim 1, including: means with
said first tubular member for connecting said first tubular member
with another section of the well conduit after said second tubular
member is released wherein said first tubular member is connectable
to a well conduit.
3. The apparatus as set forth in claim 1 wherein said means for
effecting release of said lug means from said locking recess,
including:
a. a helical groove formed in said first tubular member; and
b. said lug means moving along said groove when said first and said
second tubular member are rotated relative to each other until said
lug means moves from said locking recess wherein the safety joint
is released.
4. The apparatus as set forth in claim 3, wherein:
said helical groove effecting a left-hand engagement with said lug
means wherein relative right-hand rotation between said first and
said second tubular members releases the safety joint.
5. The apparatus as set forth in claim 1, wherein:
said piston means having first pressure responsive surface and
second pressure responsive surface, said piston means moving to the
locking position in response to the pressure urging on said first
pressure responsive surface and moving to the released position in
response to the pressure urging on said second pressure responsive
surface.
6. The apparatus as set forth in claim 5, wherein:
said first pressure responsive surface and said second pressure
responsive surfaces have the same pressure urging thereon to block
movement of said piston means until the predetermined pressure
urges movement of the piston means to the release position.
7. The apparatus as set forth in claim 5, wherein:
a. said piston means is a sleeve concentrically mounted about said
second tubular member and forming a first expansible chamber and a
second expansible chamber therebetween;
b. said first pressure responsive surface forming a portion of said
first expansible chamber for urging movement of said piston sleeve
to the locking position in response to the pressure in said first
chamber; and
c. said second pressure responsive surface forming a portion of
said second expansible chamber for urging movement of said piston
sleeve to the released position in response to the pressure in said
second chamber wherein the piston moves to release the safety joint
when the predetermined pressure is communicated into said second
chamber.
8. The apparatus as set forth in claim 7, wherein:
a. said second tubular member having a first flow port and a second
flow port formed therethrough in spaced relationship to receive a
bridge plug therebetween;
b. said first flow port communicating said first expansible chamber
with said bore of said second tubular member;
c. said second flow port communicating said second expansible
chamber with said bore of said second tubular member; and
d. bridge plug means positioned in said bore of said second tubular
member for communicating the presetermined pressure in said bore of
said second tubular member through said second flow port while
blocking communication of the predetermined pressure through said
first flow port wherein the predetermined pressure urges on said
second pressure responsive surface to release the safety joint.
9. The apparatus as set forth in claim 1, wherein:
movement of said piston means to the released position vents said
predetermined pressure to indicate that positive release has been
effected.
10. The apparatus as set forth in claim 1, wherein said lug means
includes:
a plurality of moveable dogs mounted with said second tubular
member for movement to and from the engaging and free positions
wherein said dogs engage said recess at a plurality of
locations.
11. A method of alternately effecting release of subsurface safety
joint having first and second tubular members for connecting
portions of a well conduit for removing a portion of the well
conduit from the well, including the steps of:
lowering a bridge plug down the well conduit to a location within
the safety joint;
increasing the pressure in the well conduit above the bridge plug
to a predetermined pressure for urging one of the tubular members
to move relative to the other tubular member to effect release of
the safety joint in response to the predetermined pressure; and
rotating one of the tubular members of the safety joint relative to
the other tubular member to selectively effect release of the
safety joint when the urging of the predetermined pressure fails to
effect release of the safety joint wherein the safety joint is
released by rotation when the pressure urging fails to effect
release.
12. The method as set forth in claim 11, wherein the step of
rotating includes:
rotating one of the tubular members in right-hand direction to
selectively effect release of the safety joint when the urging of
the predetermined pressure fails to effect release of the safety
joint.
Description
BACKGROUND OF THE INVENTION
This invention relates to the field of a method and apparatus for a
releasable subsurface safety joint in a well and more particularly
to a safety joint that may be operated either by fluid pressure or
by mechanical movement to effect release of the safety joint.
Some subsurface well tools connectable in a well tubing string have
neither a symmetrical shape nor a concentric relationship with the
tubing string. Such tools often required employment of special
connecting joints, called safety joints, below the tool for
detaching the tool and a portion of the tubing when it was desired
or necessary to retrieve the tool to perform maintenance work
thereon. Some safety joints were released by either right-hand or
left-hand rotation of the portion of the tubing above the safety
joint, while other joints required reciprocation in conjunction
with rotation to effect release. Safety joints requiring rotation
of the well tubing were undesirable because of insufficient
clearance to enable the necessary rotation to operate the joint
which was often not available in plural completion wells and, in
addition, the risk of threadedly disengaging a threaded joint of
the well conduit was great. Other joints utilizing partial rotation
have not been widely received because the torsion deformation of
the tubing made determination of the relative position of the
tubing at the joint from the well surface unreliable.
Still others have employed reciprocation of the tubing to shear a
connecting pin to release the joint, but well pressure may effect
undesired shearing under certain well pressure conditions. Other
safety joints were released by applying fluid pressure in a certain
manner. While these often had the desirable feature of not
requiring rotation to release or separate the tools, they were
rendered inoperative if the tubing string developed a leak. It was
then necessary to pull the entire string to retrieve the tool.
The advent of subsurface safety valve controlled by the use of one
or more small lines run in parallel with the tubing string to
operate the valve has made it even more imperative that reliable
safety joints be provided. The likelihood of damage to the control
lines during the retrieval and setting of the valve rendering the
valve inoperative emphasizes the need for a reliable, non-rotating,
positive release safety joint and apparatus and method.
SUMMARY OF THE INVENTION
A method and apparatus for a subsurface safety joint connectable in
a well conduit to effect desired release of a portion of the well
conduit by either communication of a predetermined fluid pressure
to the joint to free a plurality of connecting latch dogs or by a
left-hand rotation of a portion of the well conduit. Means are
provided with the portion of the safety joint left in the well to
reconnect the well conduit with the safety joint.
An object of the present invention is to provide a new and improved
safety joint apparatus.
Another object of the present invention is to provide a new and
improved method for effecting positive release of a safety
joint.
A further object of the present invention is to provide a new and
improved safety joint having alternate means for effecting release
of the safety joint.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are side views, partially in section, from top to
bottom of the safety joint of the present invention prior to
effecting separation of the safety joint;
FIGS. 2A and 2B are views similar to FIGS. 1A and 1B respectively,
with the safety joint separation effected by left hand
rotation;
FIGS. 3A and 3B, are views also similar to FIG. 1A and 1B,
respectively, with the safety joint separation effected by a
predetermined fluid pressure communicated by the bridge plug
positioned in the bore of the safety joint;
FIG. 4 is a side view, partially in section, illustrating the lower
half of the safety joint reconnected with the well conduit above
the safety joint; and
FIG. 5 is a view taken along line 5--5 of FIG. 1B.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawings, the letter S generally designates the safety joint
of the present invention which is adapted to be connected in and
form a part of a casing, tubing or other well conduit C, whereby
the upper portion of the conduit C can be released from the lower
part of the conduit C. The lower portion of the conduit C is
suitably supported (not illustrated) in the well by a hanger and
the like to remain fixed in position when the safety joint S is
released. As set forth hereinbelow, means are provided with the
safety joint S for reconnecting the well conduit C with the safety
joint S after separation thereof.
As illustrated in FIGS. 1A and 1B, the safety joint S includes a
first or lower tubular member 10 and a second or upper tubular
member 20 having aligned longitudinal bores 10a and 20a,
respectively, formed therethrough. The lower tubular member 10
includes a threaded pin connection 11, formed thereon adjacent the
lower or first end which is adapted for connecting the tubular
member 10 with the well conduit C below the safety joint S. The
upper tubular member 20 has a threaded box connection 21 formed in
the bore 20a adjacent the upper for first end of the tubular member
20 for connecting the tubular member 20 with the well conduit C
(FIG. 2A) above the safety joint S. When connected in the well
conduit C, the safety joint S forms a portion thereof for
communicating the flow through a bore X of the well conduit C and
through the bores 10a and 20a of the tubular members 10 and 20
respectively. The bores 10a and 20a are slightly smaller in
diameter than the box X of the well conduit C for a purpose to be
more fully described hereinafter, but essentially provide a full
opening through the safety joint S for effecting a minimum flow
restriction. The tubular member 10 has a constant diameter inner
surface 10b which defines the flow passge bore 10a an outer
partially threaded surface 10c concentrically spaced from the
surface 10b. The surface 10b extends upwardly adjacent the upper or
second end of the tubular member 10 to an annular shoulder 10d. A
tapered left hand thread 10e forming a continuous helical groove or
recess in the tubular member 10 is formed in the outer surface 10c
adjacent to the shoulder 10d and which also provides a continuous
helical groove or recess below the thread 10e.
The upper tubular member 20 includes an outer sleeve 22 secured by
threads 23 to a concentric inner tubular member 24. Suitable
anti-rotation pins, not illustrated, may be employed to block
rotational disengagement of the sleeves 22 and 24. The sleeve 22
mounts an O-ring 23a adjacent threads 23 to block leakage of fluid
between the sleeve 22 and the sleeve 24.
Sleeve 22 includes a stepped lower inner surface 22a having threads
22b formed therein for releasably securing a cap ring 25 therewith.
The sleeve 22 also includes a downwardly facing annular shoulder
22c connecting the surface 22a and a smaller constant diameter
surface 22d which is concentrically spaced from the sleeve 24. The
sleeve 22 has a port 22e formed therethrough above the annular
shoulder 22c for communicating the annular space between the sleeve
24 and the surface 22d with the area adjacent the exterior surface
22f of the tubular member 22.
The inner sleeve 24 extends from the outer threads 23 to a
downwardly facing annular shoulder 24a adjacent the threads 10f.
The bore 20a is partially defined by the surfaces of the sleeve 24
including a full diameter conduit bore upper portion 24b, a bore
restricting upwardly facing annular shoulder 24c and a constant
diameter bore portion 24d having an inwardly projecting annular
collar 24e formed thereon. The collar 24e provides an upwardly
facing annular shoulder 24f for a purpose to be described more
fully hereinafter and a downwardly facing annular shoulder 24g
which is adapted to engage the upwardly facing annular shoulder 10d
of the tubular member 10 for positioning the tubular members 10 and
20 with respect to each other in the connected position.
As illustrated in greater detail in FIG. 5, a plurality of three
windows or apertures 24h are formed through the sleeve 24 adjacent
the thread 10e of the tubular member 10. The inner sleeve 24 mounts
an O-ring 24i for effecting a seal with tubular member 10 between
the annular shoulder 10b and the connecting threads 10e to block
leakage of fluid therebetween. Mounted below the threads 10f is an
O-ring 10g effecting a seal between the lower portion of the sleeve
24 and the tubular member 10 to block passage of fluid
therebetween.
The safety joint S includes a lug means L for connecting the upper
tubular member 20 with the lower tubular member 10. The lug means L
includes a plurality of latch dogs 30 mounted in the corresponding
plurality of windows 24h which are radially moveable between an
inner or engaging position (FIG. 1B) for connecting or securing the
tubular member 20 with the tubular member 10 and to and from an
outer or free position (FIG. 3B) for enabling separation or release
of the tubular member 20 from the tubular member 10. The latch dogs
30 include a tapered threaded segment or portion 30a corresponding
and threadedly engaging the left hand threads 10e.
The safety joint S further includes a piston means P operably
connected with the latch dogs 30 for enabling separation of the
safety joint S when a predetermined pressure urges on the piston
means P. The piston means P includes a piston sleeve 40
concentrically mounted about the sleeve 24, such sleeve 40 being
moveable longitudinally between an upper or locking position (FIG.
2B) for retaining the latch dog threads 30a in engagement with the
threads 10e, and a lower or release position (FIG. 3B) to enable
the latch dogs 30 to move to the free position for effecting
separation of the safety joint S. The piston sleeve 40 has a
constant diameter inner surface 40a which engages a constant
diameter locking outer surface 30b of a plurality of spaced annular
collars 30c formed on the latch dogs 30 when the piston sleeve 40
is in the locking position. When in this position, the piston
sleeve 40 locks the threads 30a of the latch dogs 30 in engagement
with the threads 10e of the tubular member 10 for connecting the
tubular member 10 and the tubular member 20. The inner surface 40a
of the piston sleeve 40 includes a plurality of correspondingly
spaced annular recesses 40b formed therein adapted to receive the
annular collars 30c of the latch dogs 30 therein when the piston
sleeve 40 moves to the release position which enables the latch
dogs 30 to move outwardly for releasing the engagement of the
threads 10e and 30a. The piston 40 carries an O-ring 40c to
slideably seal between the piston sleeve 40 and the sleeve 24
adjacent the lower end of the piston sleeve 40 to block leakage of
fluid therebetween. The sleeve 24 carries an O-ring 24j for
slideably sealing with the piston sleeve 40 to prevent leakage of
fluid therebetween above the recesses 40b.
As illustrated in FIG. 1, the piston sleeve 40 has an upwardly
facing annular shoulder 40d engaging a downwardly facing annular
shoulder 25a of the cap ring 25 to provide a movement stop when the
piston sleeve 40 is in the locking position. The surface 40a of the
piston sleeve 40 has an inwardly projecting annular collar 40e
formed thereon having a downwardly facing annular shoulder 40f and
an upwardly facing annular shoulder 40g. The collar 40e mounts an
O-ring 40h thereon for slideably sealing the collar 40e with the
sleeve 24 to prevent leakage of fluid therebetween.
The sleeve 24 has an annular shoulder 24k formed thereon above the
collar 40e for receiving a ring stop member 41 between the sleeve
22 and the piston sleeve 40. The engagement of the stop ring 41
with the annular shoulder 24k blocks downwardly movement of the
stop ring 41 relative to the inner sleeve 24 and the ring stop
member 41 is fluted at the outer portion 41a where it engages the
piston sleeve 40 to enable communication of the fluid pressure
across the member 41. As illustrated, a gapped radially expansible
detent ring 42 having a tapered upper surface 42a is positioned
immediately above the ring 41 and an annular recess 40i having a
tapered upper portion 40j corresponding to the tapered surface 42a
is formed in the surface 40a of the sleeve 40.
The detent ring 42 engages the tapered portion 40j to block or
resist inadvertent downwardly movement of the piston sleeve 40 from
the locked position to the release position. When the predetermined
pressure for operating the piston sleeve 40 is applied, the tapered
portion 40j will cam or wedge the detent ring 42 from the recess
40i to enable the piston sleeve 40 to move to the release position.
A latch ring 43 is positioned between the piston sleeve 40 and the
tubular member 24 above the stop ring 41 and carries a pair of
O-rings 43a and 43b for slideably sealing the longitudinally
moveable latch ring 43 with the piston sleeve 40 and the sleeve 24,
respectively. The latch ring 43 includes an upwardly facing
pressure responsive annular shoulder surface 43c and a downwardly
facing pressure responsive shoulder surface 43d with the pressure
responsive surface 43c communicating with the pressure adjacent the
exterior surface 22f of the outer sleeve 22 through the port 22e.
The latch ring 43 moves in response to the differential pressure
urgings thereon between a lower position (FIG. 1A) and an upper
position (FIG. 3A). The pressure responsive surface 43d has a
ring-shaped extension 43e extending downwardly therefrom which fits
within the detent ring 42 when the detent ring 42 expands into the
recess 40i to block inadvertent movement of the detent ring 42 from
the recess 40i. The extension 43c has a flow port 43f formed
therethrough to enable communication of fluid pressure to the
pressure responsive surface 43d.
The latch ring 43 includes an annular recess 43g formed adjacent
the cap ring 25 which aligns with a gapped radial expansible snap
ring 44 carried on the surface 22a of the sleeve 22 chich contracts
into the recessed 43f when aligned therewith. The recess 43g and
the snap ring 44 are provided with square shoulders in order that
the snap ring 44 will not be wedged out of the recess 43f to free
the latch ring. By securing the latch ring 43 in the upper position
in this manner, the latch ring 43 will not drop down to re-lock the
detent ring 42 in the recess 40i with the downwardly extending
extension 43e or otherwise interfere with the release of the safety
joint S. The operation of the detent ring 42 and the snap ring 44
block inadvertent release and insure positive release of the safety
joint S, respectively.
The piston sleeve 40, the sleeve 22 and the tubular member 10 are
also secured together by a threaded shear pin 50 to block
inadvertent or undesired separation of the safety joint S.
The concentric spaced relationship of the piston sleeve 40 and the
sleeve 22 adjacent the collar 40e forms a first annular expansible
chamber 60 between the seals effected by the O-rings 40h and 24j
below the downwardly facing annular shoulder 40f. The piston sleeve
40 and the sleeve 22 also form an expansible annular chamber 61 in
the space therebetween sealed by the O-rings 40h, 43a and 43b above
the upwardly facing annular shoulder 40d of the piston sleeve 40.
Fluid pressure in the chamber 60 will urge on the pressure
responsive surface 40f to urge movement of the piston means 40
upwardly to the locking position with the shoulder 40d in
engagement with the cap ring 28. The pressure of the fluid in the
annular expansible chamber 61 urges on the pressure responsive
surface 40g to urge downwardly movement of the piston 40 to the
release position and on the surface 43d of the latch 43 to urge
movement of the latch 43 to the upper position. The inner sleeve 24
has a pair of flow ports, 24m and 24n formed therethrough for
communicating the pressure in the bore 20a into the chambers 60 and
61 respectively. By having the pressure responsive surfaces 40f and
40g of the piston 40 of the same effective surface area, the piston
will have offsetting pressure urging thereon in normal operation
and will remain in the locked position until it is desired to apply
the predetermined pressure for effecting movement of the piston
sleeve 40 to the release position. One skilled in the art may vary
the relative size of these areas without departing from the spirit
of the present invention. The ports 24m and 24n are spaced a
sufficient distance to receive a bridge plug means B therebetween
for communicating a predetermined pressure through the flow port
24n while blocking its communication through the flow port 24m.
As illustrated in FIG. 3A, the bridge plug means B includes a
tubular plug assembly 70 which is properly dimensioned to move
freely through the bore X of the well conduit C and the bore 20a in
the tubular member 20. The tubular assembly 70 has a downwardly
facing annular tapered lower seating surface 70a which engages the
upwardly facing annular shoulder 24f of the collar 24e to operably
position the tubular unit 70 in the bore 20a. The tubular assembly
70 mounts a set of chevron packing 70c to effect a seal with the
surface 24d of the sleeve 24 to block leakage of fluid
therebetween. When the tubular unit 70 is operably positioned by
the seating shoulder 70a, the packing 70c effects the seal with the
surface 24d between the spaced flow ports 24m and 24n. Thus, the
tubular plug assembly 70 when operably positioned in the bore 20a
enables communication of the port 24n with the bore 20a and the
bore X of the conduit C above the assembly 70 while blocking
communication of this area with the port 24m. The tubular unit 70
has a flow port 70d formed therein adjacent the port 24m for
communicating the flow port 24m with a bore 70e of the tubular plug
assembly 70. The flow port 70d enables the venting or exhausting of
the expansible chamber 60 into the bore 20a of the tubular member
20 below the plug assembly 70 when the piston 40 moves to the
release position. The tubular plug assembly 70 includes a fishing
neck 70f moveably secured thereto to enable retrieval of the plug
assembly 70 when desired by a fishing operation. The fishing neck
70f is normally urged by a spring 70g to block communication
through the bore 70e but which moves to vent through the assembly
70 when retrieving the assembly 70 by the fishing operation as is
well known in the art.
As illustrated in FIG. 4, a reconnection tool 80 provides a means
for connecting the tubular member 10 with the well conduit C above
the tubular member 10 after release of the safety joint S is
effected. The reconnection tool 80 is provided with the standard
threaded box connection (not illustrated) for connecting the tool
80 with the well conduit C above the tool 80. The reconnection tool
80 has a positioning skirt 80a properly dimensioned to center the
tool 80 in the well to center and align the tool 80, with the
threads 10f of the tubular member 10. Right-hand rotation of the
conduit C and reconnection tool 80 will then reconnect the well
conduit C by engaging right-hand threads 80b with the threads 10f.
The right-hand rotation to connect is preferred in that it
eliminates the possibility of a threaded well conduit C connection
becoming disengaged during employment of the reconnection tool 80.
The reconnection tool 80 carries an O-ring 80c in a recess formed
therein to seal with the tubular member 10 adjacent the annular
shoulder 10d to block leakage of fluid therebetween when the
threads 80b and 10f are fully engaged. The reconnection tool 80 has
a bore 80d therethrough aligned with the bore X of the well conduit
C and the bore 10a of the tubular member 10 to enable production of
hydrocarbons and the like therethrough.
In the use and operation of the present invention, the safety joint
S is prepared for use in a well by assembling the joint S in the
condition illustrated in the FIGS. 1A and 1B. The piston sleeve 40
is in the dog 30 locking position and secured therein by the detent
ring 43 and the latch ring extension 43e as well as by the shear
pin 50. The threaded portions 30a of the dogs 30 engage the threads
10e of the tubular member to connect the tubular members 10 and 20
of the safety joint S. The safety joint S is connected in the well
conduit C at any desired location using the threaded pin 11 and box
21 connections as is well known in the art. When connected in the
well conduit C, the safety joint enables the flow of hydrocarbons
and the like through the bore X of the well conduit C from a
producing formation to the wall head.
When it is desired to remove a portion of the well conduit C, above
the safety joint S, the positive release of the safety joint S may
be effected in either of two alternate ways. The preferable mode is
hydraulic release in that rotation of the well conduit C above the
safety joint S is not required to effect release thereby reducing
the likelihood of damage to non-concentric tools connected in the
well conduit C, and safety valve control lines. To effect hydraulic
release, the tubular plug assembly 70 is positioned in the bore X
of the well conduit C at the surface and allowed to flow, drop,
fall or otherwise move down the bore X of the conduit C until it
engages the seating shoulder 24f of the sleeve 24 with the seating
shoulder 70a to operably position the tubular plug assembly 70 in
the bore 20a. By connecting a pump or other pressure generating
means to the bore X of the well conduit C at the surface, the
pressure in the bore 20a above the plug may be increased to any
desired predetermined value. The plug assembly 70 enables the
pressure in the bore 20a above the plug 70 to be communicated
through the port 24n into the annular expansible chamber 61 while
blocking the communication of this pressure through the flow port
24m into the chamber 60.
The predetermined pressure communicated into the chamber 61 urging
on the surface 43d for urging the latch ring 43 to move upwardly is
greater than the pressure communicated through the port 22e urging
on the surface 43c for urging movement of the latch ring 43
downwardly, hence the latch ring 43 will move to the upper
position. When the recess 43f of the latch ring is aligned with the
snap ring 44, the snap ring will contract into the recess 43f to
maintain the latch ring 43 in the upper position. The upwardly
movement of the latch ring 43 moves the detent locking extension
43e from within the detent ring 42 to release the detent 42. When
the recess 43g of the latch 43 aligns with the snap ring 44, the
snap ring 44 will contract to move into the recess 43g for holding
the latch 43 in the upper position.
The pressure in the chamber 61 also urges downwardly on the
upwardly facing pressure responsive surface 40g of the piston
sleeve 40 for effecting movement of the piston sleeve downwardly to
the release position. Since the increased pressure in the bore 20a
above the plug assembly 70 is not urging upwardly on the pressure
responsive surface 40f for urging the position to move upwardly to
the lock position, downward movement of the piston sleeve 40 to the
released position will be effected by the predetermined pressure.
As the piston sleeve 40 commences to move downwardly, the detent
ring 42 will be wedged inwardly by the tapered edge 40j of the
recess 40i to enable the piston sleeve 40 to move downwardly. The
shear pin 50 will also be sheared by the initial pressure
responsive movement of the piston sleeve 40. The piston sleeve 40
will continue to move downwardly until the O-ring 40h no longer
effects a seal with the sleeve 22 and communication between the
chambers 60 and 61 is thus enabled and which results in an
equalization of pressure about the plug assembly 70. This pressure
equalization effects a pressure drop monitorable at the surface to
indicate to the operator that positive hydraulic release has been
effected by the movement of the piston to the release position.
The movement of the piston sleeve 40 to the release position aligns
the annular recesses 40b with the locking collars 30c of the latch
dogs 30. When the well conduit C above the joint is manipulated by
pulling upwardly, the taper of the engaged threads 30a and 10e will
wedge or cam the latch dogs 30 outwardly to effect a release or
separation of the upper tubular member 20 from the lower tubular
member 10.
Should the hydraulic release not operate for any reason, release of
the safety joint S can still be effected by manipulating the well
conduit C. By rotating the well conduit C in a right-hand
direction, the left-hand engagement of the threads 30a and the
threads 10e will be disengaged. The initial rotation will shear the
shear pin 50 between the sleeve 22 and the tubular member 10. While
the right-hand rotation for release is preferred in that the
threaded well conduit C connections will not be disengaged, the
rotation of the well conduit C may damage the connected well tools
and is thus employed as a back-up only when the hydraulic pressure
release cannot be effected.
After separation of the safety joint S has been accomplished, the
well conduit C may be connected with the upper end of the tubular
member 10 by the use of the tool 80. The tool 80 is secured to the
lower end of the wall conduit C and lowered down the well until the
tool 80 engages the threads 10f of the tubular member 10.
Right-hand rotation of the well conduit C and the reconnection tool
80 will engage the threads 80b and 10f for connecting the tubular
member 10 with the tool 80. Thereafter, the well may be produced
through the aligned and communicating boxes X, 10a and 80d as is
well known in the art.
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the
size, shape, and materials as well as in the details of the
illustrated construction may be made without departing from the
spirit of the invention.
* * * * *