U.S. patent number 3,661,206 [Application Number 05/054,527] was granted by the patent office on 1972-05-09 for underwater completion expanding tubing hanger.
This patent grant is currently assigned to FMC Corporation. Invention is credited to Carl R. Hutchison, Samuel W. Putch.
United States Patent |
3,661,206 |
Putch , et al. |
May 9, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
UNDERWATER COMPLETION EXPANDING TUBING HANGER
Abstract
An apparatus for suspending a string of pipe in an oil or gas
well at the wellhead, and particularly for hanging one or more
tubing strings in the casing head of an offshore underwater well.
Included are an assembly for hanging the tubing strings, a tool
assembly for running and retrieving the tubing hanger assembly, and
a tool assembly for running and retrieving a tubing hanger coupling
and for completing the well. The apparatus facilitates running,
aligning, and landing all the tubing strings, pressure testing the
tubing hanger, and locking the hanger down, all in one trip.
Inventors: |
Putch; Samuel W. (Houston,
TX), Hutchison; Carl R. (Houston, TX) |
Assignee: |
FMC Corporation (San Jose,
CA)
|
Family
ID: |
21991715 |
Appl.
No.: |
05/054,527 |
Filed: |
July 13, 1970 |
Current U.S.
Class: |
166/89.2;
166/208; 166/313; 285/123.2; 166/189; 166/237; 285/315 |
Current CPC
Class: |
E21B
33/047 (20130101); E21B 43/10 (20130101) |
Current International
Class: |
E21B
33/03 (20060101); E21B 33/047 (20060101); E21B
43/10 (20060101); E21B 43/02 (20060101); E21b
033/03 (); E21b 023/00 () |
Field of
Search: |
;166/85,88,89,208,217,237
;285/18,24,27,137,140,141,142,143,315,317,321,322 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Claims
We claim:
1. A well pipe hanger assembly for suspending one or more strings
of pipe in a fluid-producing well, comprising
a. a generally cylindrical hanger body having at least one axial
bore therethrough, said body having upper and lower ends with said
upper end adapted for releasable connection to a well tool;
b. a resilient, self-expandable hanger support ring circumscribing
said hanger body and carried thereon for free radial movement
between contracted and expanded positions;
c. mandrel means for locking said hanger support ring in its
expanded position;
d. mandrel actuator means for moving said mandrel means into its
hanger support ring locking position;
e. means for aligning said hanger assembly;
f. pipe coupling means seated in said hanger body and releasably
secured against upward movement therefrom;
g. fluid seal means between said hanger body and said pipe coupling
means;
h. means in said hanger body for testing the integrity of said seal
means before said hanger assembly is installed in an outer pipe
element; and
i. means in said hanger body for testing the integrity of said seal
means after said hanger assembly is installed in said outer pipe
element.
2. A pipe hanger assembly according to claim 1 wherein said mandrel
actuator sleeve includes means for releasably and non-rotatably
connecting said sleeve to a well tool, and wherein said mandrel
means is moved into its hanger support ring locking position by
rotation of said well tool and said mandrel actuator sleeve.
3. A pipe hanger assembly according to claim 2 wherein rotation of
said well tool also releases its connection to said hanger
body.
4. A pipe hanger assembly according to claim 1 wherein said
aligning means comprises an alignment sleeve circumscribing said
hanger body and an alignment key biased outwardly from said
alignment sleeve, said alignment key cooperating with an outer pipe
element to permit rotation of said hanger assembly in that pipe
element until said assembly is aligned therein, and then to
preclude further rotation of said alignment sleeve and said hanger
body.
5. A pipe hanger assembly according to claim 4 wherein said
alignment sleeve is threadedly connected to said hanger body, and
said mandrel comprises a ring-like body portion and a plurality of
circumferentially-spaced fingers depending therefrom, said fingers
extending between said alignment sleeve and said hanger body in
grooves positioned longitudinally in said hanger body.
6. A pipe hanger assembly according to claim 1 including a
releasable connection between said hanger body and said well took,
said connection comprising a split-ring locking element, a
ring-expanding mandrel, and an annular groove into which said
locking element can be expanded.
7. A pipe hanger assembly according to claim 6 wherein said
split-ring locking element and said ring-expanding mandrel are
components of said well tool, said hanger body includes a centrally
positioned bore in its upper portion, and said annular groove is
located in said centrally positioned bore.
8. A pipe hanger assembly according to claim 1 wherein said mandrel
actuator means comprises a rotatable sleeve circumscribing said
hanger body and threadedly engaging said mandrel means, said sleeve
including at least one slot in its upper end to accommodate a key
fixed to said well tool.
9. A pipe hanger assembly according to claim 1 wherein said
aligning means includes means for accepting and aligning an outer
well completion element with said hanger assembly, and means for
accepting and aligning an inner well completion and servicing
tool.
10. A well tool assembly for running and retrieving a well pipe
hanger assembly, comprising
a. an annular body with an upper section adapted for connection to
a pipe string, a lower section adapted for releasable connection to
said hanger assembly, and an intermediate section with external
threads for moving a circumscribing tool element axially
thereon;
b. an annular clutch and mandrel means circumscribing said body,
said means including internal threads complementary to said
external threads on said body, a mandrel section for preventing
contraction of an annular element against said body, and means for
releasably engaging a rotatable pipe hanger element to cause said
element to rotate in concert with said well tool;
c. an annular resiliently expandable and contractible locking
element surrounding said body; and
d. first and second stop means spaced axially on said body for
restricting axial movement of said clutch and mandrel means on said
body to a predetermined area,
whereby when said clutch and mandrel means is threadedly engaged
with said body and releasably engaged with said pipe hanger
element, rotation of said body will cause said clutch and mandrel
means to move axially on said body, to release said annular locking
element for contraction, and to rotate said pipe hanger
element.
11. A well tool assembly according to claim 10 wherein rotation of
said body causes said clutch and mandrel means first to move
axially into contact with said second stop means, and then to
rotate with said body.
12. A well tool assembly according to claim 10 wherein said first
stop means comprises an annular shoulder on said body, said second
stop means comprises a snap ring residing in an external annular
groove on said body, and wherein said clutch and mandrel means
includes a pair of keys for engaging complementary slots in said
rotatable pipe hanger element.
13. A well tool assembly, comprising
a. a generally cylindrical body having at least one axial bore
therethrough, said body having upper and lower ends with said lower
end adapted for cooperatively engaging a well pipe hanger
assembly;
b. at least one mandrel sub rotatably extending through a bore in
said body and threadedly engaged therewith;
c. means for releasably connecting said mandrel sub to a pipe
coupling in said pipe hanger assembly and
d. means for selectively releasing said pipe coupling from said
pipe hanger assembly to facilitate removal of said coupling from
said assembly.
14. A well tool assembly according to claim 13 including means for
aligning said well tool assembly with said pipe hanger
assembly.
15. A well tool assembly according to claim 13 wherein said
connecting means comprises a collet with flexible fingers, said
collet circumscribing said mandrel sub and secured to said
body.
16. A well tool assembly according to claim 15 wherein said collet
has enlarged portions on its flexible fingers for engaging an
internal annular groove in said pipe coupling, and said mandrel sub
includes a locking surface for locking said enlarged finger
portions into said pipe coupling's annular groove.
17. A well tool assembly according to claim 13 wherein rotation of
said mandrel sub in said body, when said tool assembly is properly
positioned with said pipe hanger assembly, locks said mandrel sub
to said pipe coupling.
18. A well tool assembly according to claim 13 wherein said
selectively releasing means comprises a ring-like element
circumscribing said mandrel sub and selectively positionable in a
locking and an unlocking location with respect to the pipe
coupling.
19. A tool assembly according to claim 13, including a plurality of
bores through said body, a mandrel sub in at least one of said
bores, a collet for locking said mandrel sub to a pipe coupling,
and a multi-positionable release ring for selectively releasing
said pipe coupling from said pipe hanger assembly.
20. A well tool assembly, comprising
a. a generally cylindrical body having at least one axial bore
therethrough, said body having upper and lower ends with said lower
end adapted for cooperatively engaging a well pipe hanger
assembly;
b. at least one mandrel sub rotatably extending through a bore in
said body and threadedly engaged therewith; and
c. means circumscribing said mandrel sub and secured to said body
for releasably and non-threadedly connecting said mandrel sub to a
pipe coupling in said pipe hanger assembly as said mandrel sub is
rotated.
21. A well tool assembly according to claim 20 including means for
aligning said well tool assembly with said pipe hanger
assembly.
22. A well tool assembly according to claim 20 wherein said
connecting means comprises a collet with flexible fingers.
23. A well tool assembly according to claim 22 wherein said collet
has enlarged portions on its flexible fingers for engaging an
internal annular groove in said pipe coupling, and said mandrel sub
includes a locking surface for locking said enlarged finger
portions into said pipe coupling's annular groove.
24. A well tool assembly according to claim 20 wherein rotation of
said mandrel sub in said body, when said tool assembly is properly
positioned with said pipe hanger assembly, locks said mandrel sub
to said pipe coupling.
25. A well tool assembly according to claim 20 wherein said
selectively releasing means comprises a ring-like element
circumscribing said mandrel sub and selectively positionable in a
locking and an unlocking location with respect to the pipe
coupling.
26. A tool assembly according to claim 20, including a plurality of
bores through said body, a mandrel sub in at least one of said
bores, a collet for locking said mandrel sub to a pipe coupling,
and a multi-positionable release ring for selectively releasing
said pipe coupling from said pipe hanger assembly.
27. A well apparatus comprising, in combination
a. a well pipe hanger assembly;
b. means attachable to said well pipe hanger assembly for running
said assembly into a wellhead element;
c. means secured to said well pipe hanger assembly for aligning
said assembly with said wellhead element;
d. means secured to said well pipe hanger assembly for landing said
assembly in said wellhead element;
e. means secured to said well pipe hanger assembly for locking down
said assembly in said wellhead element; and
f. means in said well pipe hanger assembly for testing the
integrity of fluid-tight seals that are established between said
assembly and well pipe when said well pipe is hung in said
assembly, said well apparatus facilitating running, aligning,
landing, locking down and testing said well pipe hanger assembly in
one trip into the well.
Description
BACKGROUND OF THE INVENTION
The field of art to which this invention pertains includes devices
for suspending pipe in wells or shafts bored into the earth, and
more particularly to such devices for suspending one or more
strings of tubing from the wellhead. In a specific sense, the
invention relates to pipe hangers that include a self-expanding
support ring that is adapted to expand into a predesignated groove
system in an outer tubular member to land and ultimately lock the
hanger to this tubular member, to apparatus for running and
retrieving such pipe hangers, to apparatus for completing the well
through such pipe hangers and, where desired, for running and
retrieving one or more pipe strings through the hanger, and also to
methods for carrying out the foregoing.
In the practice of drilling off shore underwater wells for the
recovery of valuable fluids such as oil and natural gas, it is
customary to support the drilling rig on a floating vessel, or on
the ocean, etc. floor when in shallow water, and to complete the
well ready for production either on a platform at the water surface
or, more modernly, on the bottom or floor of the ocean. Generally
speaking, as the water depth increases the degree of difficulty in
completing the well, including the time required, also increases.
As a result, much effort has been devoted to reducing the time
factor involved in completing underwater wells, improving the
reliability and safety of the equipment used in such completions,
and generally attempting to bring the overall cost factor of
underwater well completions more within the reasonable range of
land-based wells.
An outstanding example of the results of this endeavor is the
Underwater Completion (UWC) system designed and manufactured by the
Oil Center Tool (OCT) Division of FMC Corporation, Houston, Texas.
This system, described in detail in OCT's booklet entitled "Oil
Center Tool Underwater Completion System," involves the following
general procedure. The conductor pipe is driven, drilled, or jetted
into place. In the conductor string is a conductor housing that
attaches to a permanent guide base that rests on the ocean floor.
After drilling the hole to the desired depth, the surface casing is
attached to the bottom of the wellhead body, and is run using the
wellhead body running tool. This surface string is guided into the
conductor pipe by a universal guide arm unit. After cementing the
surface string, the wellhead body running tool is retrieved. The
blowout preventers, which are attached to the top of a "Torus"
connector, are run down the guide cables and connected to the
wellhead body by this connector. The hole is drilled deeper, the
intermediate string is run, cemented, packed off and tested, and
the hole then is drilled to completion depth and the oil string is
run, using the same procedure as used for the intermediate string.
With the blowout preventers in place on the wellhead body, the test
plug is removed, and the tubing hanger and tubing strings are run,
completing the well. The present invention concerns a new type of
tubing hanger for the last phase of this procedure, and the
equipment and techniques involved in utilizing it.
Each of the underwater completion tubing hangers known to the
industry today presents one or more problems in their use. For
example, the very high pressures sometimes encountered in offshore
wells can be destructive of the hanger equipment if it should
escape past the packings or seals. This is particularly true where,
as is customary, the tubing hangers are supported by one or more
casing hangers, which in turn find their support on the wellhead.
Another problem with these prior devices is that they undesirably
restrict the number of tubing strings that can be included in a
given size hanger, thus requiring larger and more expensive
equipment to achieve a result that a smaller hanger should
facilitate. Many of the known hangers require the use of a
considerable number of tools to manipulate them, several trips to
accomplish their installation, and they sometimes fail to provide a
positive lock-down indication. Yet another problem with the use of
prior hangers is their lack of flexibility to accomodate various
numbers of strings, i.e., they are designed for a given number and
only that number can be handled.
SUMMARY OF THE INVENTION
Broadly considered, the present invention includes a pipe or tubing
hanger assembly for a fluid producing well, a tool assembly for
running and retrieving the hanger assembly, a tool assembly for
completing the well and for running and retrieving one or more
tubing hanger couplings and the strings of tubing connected
thereto, and the procedure involved in the foregoing. The tubing
hanger assembly includes facilities to run, align and land all the
tubing strings, pressure testing the hanger, and locking it down
into the wellhead, all during one trip into the well. The tubing
hanger running and retrieving tool assembly includes facilities to
releasably connect the tool to the hanger, land and lock the hanger
into the wellhead, release its connection to the hanger, and for
retrieval from the remotely located well. The completion and tubing
hanger coupling running and retrieving tool assembly includes
facilities to complete the well, to run and retrieve one or more
preselected tubing strings from the surface to the tubing hanger,
and also to retrieve any one or all of the tubing strings suspended
in the well from the hanger.
The tubing hanger includes an inherently self-expandable support
ring that functions to land and lock the hanger into the wellhead,
releasable locking dogs to secure tubing hanger couplings in the
hanger body, and a fluid test passage and port system to determine
the integrity of the fluid seals between the hanger body and the
couplings. The hanger running and retrieving tool assembly includes
a clutch and mandrel nut that functions both to release the tool
from the hanger and to power an actuator sleeve on the hanger to
maintain the self-expanding support ring in its locking position.
The completion and tubing hanger coupling running and retrieving
tool assembly includes collet-type locking mechanisms for securing
the tool to the tubing hanger couplings, rotatable mandrel subs to
secure the collet fingers in their locking position, and
positionable release rings for unlocking the tubing hanger
couplings from the hanger body. The apparatus further includes
alignment elements to properly align the tubing hanger assembly
with the wellhead, the two tool assemblies with the hanger, and the
connector device for coupling blowout preventers and a Christmas
tree to the wellhead in proper position with respect to the tubing
strings.
Accordingly, one object of this invention is to overcome each of
the aforementioned problems associated with the use of prior tubing
hangers apparatus, especially in underwater wells.
Another object of this invention is to provide a new single or
multiple string tubing hanger apparatus that can be installed in
the well in one trip.
Another object of this invention is to provide a new underwater
completion tubing hanger apparatus that involves less parts,
requires less tools and time for installation and removal, and is
more versatile, flexible, and reliable than the presently available
apparatus for this same general purpose.
Still another object of this invention is to provide a tubing
hanger apparatus that, although designed particularly for use in
underwater wells, is more proximate to the cost of land-based
hanger equipment, especially in terms of time required to
manipulate the hanger and the expense involved in its
construction.
Yet another object of this invention is to provide a tubing hanger
apparatus that is landed and locked directly to the well's casing
head, rather than to a casing hanger as is the current practice,
thereby transmitting all of the weight of the tubing string or
strings directly to the casing head and providing a more secure
suspension of the tubing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in elevation and in section of the tubing hanger
assembly of this invention, attached to its running and retrieving
tool assembly, and landed in the bore of a casing head constituting
part of an underwater well completion system.
FIG. 2 is an enlarged view of the tubing hanger assembly taken
along the line 2--2 of FIG. 1, showing the alignment dog for
aligning the tubing hanger in the casing head.
FIG. 3 is a view taken along the line 3--3 of FIG. 1, showing the
tubing hanger lockdown dogs in locking position with respect to the
tubing hanger couplings.
FIG. 4 is a view taken along the line 4--4 of FIG. 1, illustrating
the threaded engagement of the tubing hanger body with the
alignment sleeve, and the lower fingered portions of the
mandrel.
FIG. 5 is a view like FIG. 1, showing a portion of the tubing
hanger assembly as it appears following the completion of the first
phase of locking it into the casing head.
FIG. 6 is a view like FIG. 1, showing the tubing hanger assembly
locked into the casing head, and the hanger running and retrieving
tool assembly released from the tubing hanger assembly.
FIG. 7 is a view like FIG. 6, showing the tubing hanger assembly
locked into the casing head, the completion and tubing hanger
coupling running and retrieving tool assembly landed in, but not
yet locked into, the tubing hanger assembly, and the tubing hanger
coupling release rings in the upper or unlocked position.
FIG. 8 is an enlarged view of a portion of the apparatus
illustrated in FIG. 7, showing the completion and tubing hanger
coupling running and retrieving tool assembly locked into the
tubing hanger assembly.
FIG. 9 is a view like FIG. 8, showing the completion and tubing
hanger coupling running and retrieving tool assembly landed in, but
not yet locked into, the tubing hanger assembly, and with the
coupling release rings in the lower or locked position.
FIG. 10 is a view like FIG. 9, showing the completion and tubing
hanger coupling running and retrieving tool assembly locked into
the tubing hanger assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As stated previously, the apparatus of this invention comprises a
tubing hanger assembly, a tubing hanger running and retrieving tool
assembly, and a completion and tubing hanger coupling running and
retrieving tool assembly, these assemblies interrelated such that
the tubing string or strings can be run into the well and locked
and sealed to the well head, and can be retrieved from the well
head, with a minimum of procedural steps and during only one round
trip into the well. The currently preferred form of the apparatus
is illustrated in the drawings, and although the following
description is directed primarily to these drawings it is to be
understood that they are illustrative of but merely one form the
invention can take. For example, instead of a dual tubing
completion system as shown in the drawings, the invention can be
used just as well with single, triple, quadruple or other multiple
completions. Thus, the following description is not to be construed
as limiting the invention to a dual completion system, but rather
as an exemplification of one style of system in which the invention
can be implemented.
FIGS. 1 through 6 illustrate the tubing hanger assembly and the
tubing hanger running and retrieving tool assembly of this
invention, and it is in conjunction with these Figures that these
two assemblies will be described. With reference to FIGS. 1 through
4, the tubing hanger assembly 20 comprises a generally cylindrical
tubing hanger body 22, a resilient self-expandable support ring 24,
and alignment sleeve 26, a mandrel 28, a mandrel actuator sleeve
30, a pair of lockdown dogs 32, and an alignment dog 34. In this
embodiment of the invention, the tubing hanger body 22 has a pair
of bores 22a for receiving and supporting a pair of tubing hanger
couplings 36, 38, the couplings have upper annular shoulders 36a,
38a that land and seat upon the hanger body's upper shoulders 22b,
and lower annular shoulders 36b, 38b that similarly land and seat
upon the hanger body's lower shoulder 22c. The lower ends of the
tubing hanger couplings 36, 38 have internal threads 36c, 38c for
connecting to the upper exteriorly threaded ends of a pair of
tubing strings 40, 42, thereby providing support for these tubing
strings in the tubing hanger body 22.
The upper end of each of the tubing hanger couplings 36, 38 has an
exterior annular groove 36d, 38d for receiving the lower portion of
one of a pair of lockdown dogs 32, when the couplings are seated in
the tubing hanger body 22 and the lockdown dogs are in their
extended or locking position as illustrated in FIGS. 1 and 3. In
this position, the upper portions of the lockdown dogs 32 extend
over the end surface of the tubing hanger couplings 36, 38, thus
ensuring a secure lock of the tubing hanger couplings into the
tubing hanger body 22. Each of the lockdown dogs 32 is biased into
its extended or locking position by a spring assembly 44, which
comprises an outer helical spring 44a surrounding an inner helical
spring 44b, and each of these spring systems 44 is backed up by a
lockdown dog cover 32a that is welded or otherwise fixed to the
tubing hanger body 22.
For purposes of providing a fluid tight seal between the tubing
hanger couplings 36, 38 and the tubing hanger body 22, each of the
couplings is provided with three annular O-rings or similar
packings 46, 48, 50. The lower portion of the tubing hanger body 22
likewise is provided with an annular packing 53 to establish a
fluid tight seal between the tubing hanger body and the adjacent
wellhead, which in this embodiment is the casing head 54. Thus,
when the tubing hanger body 22 and the hanger couplings 36, 38 are
landed, a fluid tight barrier exists between the casing head and
each of these couplings.
One of the important features of the present invention involves the
apparatus and procedure for aligning, landing, supporting and
locking the tubing hanger body in the casing head 54. This
apparatus includes the tubing hanger assembly's support ring 24,
alignment sleeve 26, mandrel 28, mandrel actuator sleeve 30, and
alignment key 34, all of which are acted upon in some manner by the
tubing hanger running and retrieving tool assembly 60. This tool
assembly 60 comprises a body 62, a clutch and mandrel nut 64, an
annular resiliently expandable and contractable locking ring 66, an
annular snap ring 68, and an annular packing element 70.
The tool body 62 has interior drill pipe threads at its upper end,
these threads providing a means of connection to the end of a drill
pipe 72 that is used to run and retrieve this tool assembly, and
also to rotate it to align the hanger assembly 20, and lock and
unlock the hanger body 22 in the casing head 54. This tool body 62
also is provided with acme threads about its exterior surface that
cooperate with complementary threads 64a in the bore of the clutch
and mandrel nut 64 to move the nut axially along the body 62, as
will be described later in more detail. The tool body 62 has an
upwardly facing, outwardly extending stop shoulder 62b, and the
lower portion of the clutch and mandrel nut 64 has an opposed
downwardly facing stop shoulder 64b, these stop shoulders
functioning to restrict axial movement of the locking ring 66 on
the body 62 when the tool assembly 60 is locked to the tubing
hanger assembly 20 as illustrated in FIG. 1. In this locked
condition, the locking ring 66, which is inherently biased towards
its contracted state, is held in the illustrated expanded state by
the nut's mandrel portion 64c, so that when the tool assembly 60 is
landed in the bore 22m at the upper end of the tubing hanger body
22, the locking ring 66 extends into an inner annular groove 72 in
the bore 22m, thereby locking the running and retrieving tool
assembly 60 to the body 22, and hence also to the tubing hanger
assembly 20. The annular packing 70 provides a fluid tight seal
between the tool assembly body 62 and the tubing hanger body 22, so
that in the locked condition, illustrated in FIG. 1, fluid tight
integrity is established between the casing head 54 and the drill
pipe 72.
The support ring 24 is split axially, is inherently
self-expandable, and is under constant bias towards its expanded
state illustrated in FIG. 1. The support ring 24 includes a
plurality of upwardly extending circumferentially spaced fingers
24a with upper portions 24b and lower portions 24c. Each of the
upper portions 24b includes an outwardly extending, downwardly
facing stop shoulder 24d, and a generally upwardly and outwardly
facing inclined camming surface 24e. The lower portion 24c of the
support ring fingers includes a generally downwardly and outwardly
facing cam surface 24f and a generally upwardly and outwardly
facing cam surface 24g. The casing head 54, or other wellhead
element designed for receiving and supporting the tubing hanger
assembly 20, includes an inner annular groove 54a for receiving the
lower portion 24c of the support ring fingers, and an inwardly
extending, upwardly facing support shoulder 54b providing a seat
for the support shoulder 24d of the support ring.
The support ring 24 is retained in position on the tubing hanger
assembly 20 by an upwardly facing, outwardly extending shoulder 22f
near the lower end of the tubing hanger body 22, and an annular
recess 26a in the lower end of the alignment sleeve 26. As is best
shown in FIG. 4, the alignment sleeve 26 is provided with internal
threads 26b that engage external threads 22g on the tubing hanger
body 22, so that the alignment sleeve and the tubing hanger body
are joined together against relative axial movement. Consequently,
although the support ring 24 is free to expand or contract, it
cannot move axially on the tubing hanger body 22. Thus, when the
tubing hanger assembly 20 is lowered into the casing head 54 until
the support ring 24 is opposite the groove 54a, the ring expands
into the groove, thereby positioning the stop shoulder 24d on the
stop shoulder 54b, and precluding further downward movement of the
ring, and hence the remaining elements of the tubing hanger
assembly 20, in the casing head 54.
Although in the condition shown in FIG. 1 the tubing hanger
assembly 20 is landed in the casing head 54, and thus cannot move
further downwardly therein, the entire assembly 20 can be withdrawn
from the casing head by simply lifting up on the drill pipe 72. As
the assembly 20 begins to move upwardly, the support ring's cam
surface 24g will cam the ring inwardly out of the groove 54a,
freeing the ring and thus the assembly 20 from the casing head.
This camming action will also occur as the surface 24e comes in
contact with any obstructions further up the wellhead or conductor
pipe, such as the lower end of the sealing sleeve 74 in the bore of
the wellhead connector apparatus 76.
In order to lock the tubing hanger assembly 20 into the casing head
54, the support ring 24 is held in its expanded state (FIG. 1) by
the mandrel 28. Looking at FIGS. 1 and 4, it is observed that the
mandrel 28 comprises an upper annular portion 28a from which depend
a plurality of circumferentially spaced fingers 28b that extend
downwardly through axial grooves 22h in the outer surface of the
tubing hanger body 22. The inner surface of the mandrel's annular
portion 28a and approximately the upper half of each of the fingers
28b are provided with right hand acme threads 28c that engage
complementary external acme threads 30a on the lower portion of the
mandrel actuator sleeve 30. The upper end of the mandrel actuator
sleeve includes a pair of diametrically positioned axial slots 30b
that receive a correspondingly positioned pair of keys 64d formed
in the upper portion of the clutch and mandrel nut 64. The mandrel
actuator sleeve's lower end 30c abuts a shoulder 22j on the tubing
hanger body 22, and the upper portion of the mandrel actuator
sleeve has a reduced diameter to provide a stop shoulder 30d which
abuts an inwardly extending, downwardly facing stop shoulder 26d on
the alignment sleeve 26. Thus, in its assembly condition as
illustrated in FIG. 1, the mandrel actuator sleeve is precluded
from axial movement with respect to the tubing hanger body 22.
Accordingly, when the clutch and mandrel nut 64 is rotated to the
left, it carries with it the mandrel actuator sleeve, and this left
hand rotation of the mandrel actuator sleeve causes the mandrel 28
to move downwardly from its position illustrated in FIG. 1 into its
locking position inside or behind the support ring 24, as
illustrated in FIG. 6, thereby preventing contraction of the
support ring and effectively and securely locking the tubing hanger
assembly into the casing head 54.
The foregoing described apparatus is, of course, installed in the
casing head after the hole is drilled to completion depth and the
various casing strings have been run. The following is an example
of the procedure for accomplishing this installation when
completing the well underwater from a drilling rig supported on a
floating vessel, or on the ocean floor such as is commonly the case
when drilling in shallow water. The well packers (not shown) and
the tubing strings 40, 42 are run into the well bore, spaced out,
and hung by slips in the rotary table at the drilling platform. The
tubing hanger assembly 20, without the tubing hanger couplings 36,
38, is stripped over the tubing strings 40, 42. The tubing hanger
couplings 36, 38 are then threaded onto the ends of the tubing
strings 40, 42, and the competion and tubing hanger coupling
running and retrieving tool assembly 100 (FIGS. 7 through 10) is
attached to the tubing hanger couplings 36, 38 by a procedure to be
described later. The slips on each tubing string are then removed,
and the couplings 36, 38 are lowered into the tubing hanger
assembly 20 until the stop shoulders 36b, 38b come to rest on the
tubing hanger body stop shoulders 22c. As this occurs the springs
44 urge the lockdown dogs 32 inwardly into locking engagement with
the couplings as illustrated in FIG. 1, thereby locking the
couplings to the tubing hanger body. The slips are then reset on
each tubing string 40, 42, and the coupling running and retrieving
tool assembly 100 is removed. The pipe plugs 78 in the lower end of
the tubing hanger body 22 are removed, a pressure test gun is
attached to the tubing hanger body, and the pressure is applied to
test the two seals 48, 50. Following the test, the gun is removed
and the pipe plugs are reinstalled. A back pressure valve (not
shown) is then installed in each tubing hanger coupling 36, 38.
The tubing hanger running and retrieving tool assembly 60 is made
up on the drill pipe 72, and with the assembly in the released
condition as shown in FIG. 5, i.e., with the clutch and mandrel nut
64 backed up against the snap ring 68, it is placed in the tubing
hanger body bore 22m with the clutch and mandrel nut keys 64d
engaging the actuator sleeve slots 30b. The tubing hanger running
and retrieving tool assembly body 62 is then rotated to the right,
such as by rotating the drill pipe 72, and because of the left
handed thread system 62a, 64a, the clutch and mandrel nut 64
travels downwardly on the body 62, expanding the locking ring 66
into the groove 72 and thereby locking the tool assembly 60 to the
tubing hanger assembly 20.
The tubing hanger assembly 20 is lowered into the well by the drill
pipe 72 until the support ring's shoulder 24d lands on the casing
head shoulder 54b. The hanger assembly 20 then is picked up
approximately 1 foot (to prevent damaging any portion or part of
the apparatus during alignment) and rotated to the right until the
alignment key 34 springs out in response to its biasing springs 34a
and catches in the groove 76a in the blow out preventer connector
76. The tubing hanger assembly 20 is then lowered until the support
ring shoulder 24d again lands on the casing head shoulder 54b, thus
placing the apparatus in the condition as shown in FIG. 1. The blow
out preventers (not shown) are closed on the drill pipe 72, and the
tubing hanger assembly 20 is tested through the preventers' kill
line (not shown). The primary seals 48 on hanger couplings 36, 38
are again tested since they are exposed to pressure through the
ports 52 in the tubing hanger body 22. The test pressure is then
bled off and the blow out preventer rams are opened.
The drill pipe 72 is then rotated to the left, and since the clutch
and mandrel nut threads 64a are left handed the nut will move up
the running and retrieving tool assembly body 62 until it comes to
rest against the snap ring 68, i.e., into the position as
illustrated in FIG. 5. Since the mandrel actuator sleeve threads
30a are right handed, and since the clutch and mandrel nut keys 64d
are still engaged with the mandrel actuator sleeve slots 30b,
further left hand rotation of the drill pipe 72 causes the mandrel
actuator sleeve 30 to rotate to the left, driving the mandrel 28
down behind the support ring 24, thereby locking the tubing hanger
assembly 20 into the casing head 54 as shown in FIG. 6. Since the
upward migration of the clutch and mandrel nut 64 withdrew its
mandrel portion 64c from behind the locking ring 66, this ring
contracted against the surface of the running and retrieving tool
assembly body 62, thereby releasing the body from the tubing hanger
body 22. Hence, the running and retrieving tool assembly 60 now can
be retrieved by simply lifting up on the drill pipe 72.
As is illustrated in FIGS. 1, 4 and 5, the alignment dog 34 is
retained in a socket 80 in the outer surface of the alignment
sleeve 26 by a plurality of roll pins 34b that extend from holes in
the side of the socket into grooves 34c in the side surfaces of the
dog 34. Thus the dog is free to move inwardly until it contacts the
inner surface of the alignment sleeve socket 80, but is prevented
from moving completely out of the socket by engagement of the pins
34b with the inner ends of the grooves 34c.
The alignment sleeve 26 has a vertical groove 26e extending
upwardly from the upper end of the socket 80 to the upper end of
the sleeve, as shown best in FIG. 2. This alignment groove 26e
cooperates with an alignment key in the bore of the Christmas tree
connector (not shown), or other component that is to be installed
on the wellhead after installation of the tubing hanger assembly
20, to align this connector, etc. with the tubing hanger assembly
and its tubing strings. The upper terminal portion of the groove
26e diverges outwardly on either side in order to provide a guide
for the alignment key as the Christmas tree connector, etc. is
rotated to position its alignment key in the groove 26e.
To complete the well following the installation of the tubing
hanger assembly 20, or to service or retrieve one or more of the
tubing strings 40, 42, the completion and tubing hanger coupling
running and retrieving tool assembly 100 is employed. As
illustrated in FIGS. 7 through 10, an assembly 100 for use with a
dual string tubing hanger such as 20 comprises a body 102 with two
axial bores 102e, 102f, an alignment key 104 for cooperation with
an inner vertical groove 26f in the alignment sleeve 26 to align
the body 102 with the sleeve as it is being installed therein,
mandrel subs 106, 108 extending through the bores 102e, 102f for
establishing a connection with each of the tubing hanger couplings
36, 38, mandrel sub stop rings 110, 112 surrounding the mandrel
subs 106, 108 and fitting into first counterbores 102g, 102h near
the lower end of the bores 102e, 102f, collets 114, 116 surrounding
the mandrel subs 106, 108, respectively, and retained in place in
the lower ends of the bores 102e, 102f by retainer rings 118, 120
that reside partially in grooves 102a, 102b in the bores and
partially in grooves 114a, 116a about the upper ends of the
collets, and coupling release rings 122, 124 releasably secured to
the collets 114, 116, respectively, by set screws 126.
The mandrel subs 106, 108 have external threads 106a, 108a that
engage internal threads 102c, 102d, respectively in the bores 102e,
102f, and external annular packings 128 are provided at the lower
ends of the mandrel subs 106, 108 to affect a fluid tight seal
between them and the tubing hanger couplings 36, 38 when they are
installed therein. The upper end of each of the mandrel subs 106,
108 is threaded into a stop coupling 130, 132, respectively, which
couplings are in turn threaded onto surface tubing strings 134, 136
that extend to the drilling or production platform. An O-ring or
other annular packing element 138 is provided between the mandrel
subs 106, 108 and the stop couplings 130, 132 to assure a fluid
tight seal therebetween.
The outer surface of each of the collets 114, 116 has an upper
annular groove 114b, 116b, and a lower annular groove 114c, 116c.
These grooves serve as locking positions for the coupler release
rings 122, 124. As is illustrated in FIGS. 7 and 8, when the
coupling release rings are secured to the upper grooves 114b, 116b,
they rest above the tubing hanger coupling lockdown dogs 32 when
the tool assembly 100 is installed in the tubing hanger 20, and
thus exert no influence on the position of the lockdown dogs.
However, when the release rings are secured to the lower grooves
114c, 116c, as illustrated in FIGS. 9 and 10, when the tool
assembly 100 is installed in the tubing hanger assembly 20 the
release rings are opposite the lockdown dogs 32, and thus hold them
in an outward or retracted position. Since the lockdown dogs 32
provide the only restriction against upper withdrawal of the tubing
hanger couplings 36, 38 from the tubing hanger body 22, when the
release rings are in the lower grooves the tubing hanger couplings,
and of course the tubing strings 40, 42 attached thereto, can be
withdrawn from the tubing hanger body 22. Hence, by selective
positioning of the release rings 122, 124 on the collets, the tool
assembly 100 can be used either to complete the well by locking the
surface tubing strings 134, 136 into the locked couplings 36, 38,
and hence into the tubing strings 40, 42, or to connect the strings
134, 136 to released couplings 36, 38 to withdraw the strings 40,
42 from the well.
To illustrate the foregoing, suppose that for servicing purposes it
is desired to connect the surface tubing strings 134, 136 to the
well tubing strings 40, 42, but not to remove these latter strings
from the well. The tool assembly 100 is made up at the surface with
the mandrel sub stop shoulders 106b, 108b spaced from the stop
rings 110, 112, as shown in FIG. 7, and the release rings 122, 124
in their upper grooves or positions 114b, 116b, respectively. The
tool assembly then is run into the wellhead by the tubing strings
134, 136, and as the enlarged lower ends of the collet fingers
114d, 116d encounter the upper ends of the tubing hanger couplings
36, 38 they are deflected inwardly to permit the continued downward
movement of the tool assembly 100 into its landed position, i.e.,
wherein the bottom end surface of the tool assembly body 102 rests
on the upwardly facing, inwardly extending shoulder 22k of the
tubing hanger body 22. At this position, the collet fingers 114d,
116d are opposite the inner annular grooves 36e, 38e in the tubing
hanger couplings. As the tool assembly 100 is lowered into the
wellhead, the alignment key 104 will either land in the groove 26f
and travel on down in that groove until the tool assembly body 102
comes to rest on the support shoulder 22k, or the key will land on
the annular beveled end surface 26g of the alignment sleeve 26. If
the key lands on the beveled surface 26g, the tool assembly 100 is
rotated, such as by placing a bar between the tubing strings 134,
136 and applying rotational force thereto, until the key falls off
the bevel 26g into the alignment groove 26f.
With the tool assembly 100 landed in the tubing hanger assembly 20
as illustrated in FIG. 7, each surface tubing string 134, 136 is
rotated to the right, thereby also rotating the corresponding
mandrel sub to which the string is attached. As the mandrel subs
rotate, their threaded engagement with the bores 102e, 102f causes
them to migrate upwardly until their stop shoulders 106b, 108b come
to rest against the stop rings 110, 112. This upward migration of
the mandrel subs 106, 108 positions their collet locking surfaces
106c, 108c behind the enlarged ends of the collet fingers 114d,
116d, thereby locking the fingers in the grooves 36e, 38e of the
tubing hanger couplings, as shown in FIG. 8. In this condition,
since the collet fingers preclude movement of the mandrel subs'
stop shoulders 106d, 108d upwardly past their enlarged lower ends,
the mandrel subs are effectively locked to the tubing hanger
couplings, and hence the surface tubing strings 134, 136 are
securely connected to the tubing strings 40, 42.
Once this connection has been achieved, the back pressure valves
(not shown) can be removed from the tubing hanger couplings in
order to set the packers and do whatever work is necessary on the
well. The back pressure valves are then reinstalled in the
couplings, and the tubing strings 134, 136 are rotated to the left,
causing the mandrel subs to move downwardly in the tool assembly
body 102 and the hanger couplings 36, 38 until the surfaces 106c,
108c are not longer behind the lower ends of the collet fingers
114d, 116d. This frees the collet fingers to move inwardly out of
the grooves 36e, 38e of the tubing hanger couplings, and the entire
tool assembly 100 can then be removed from the wellhead merely by
lifting on the surface tubing strings 134, 136.
As has been previously mentioned, it is also possible to retrieve
the lower tubing strings 40, 42 from the well with the tool
assembly 100, merely by positioning the coupling release rings 122,
124 in the lower grooves 114c, 116c on the collets 114, 116,
respectively. This position change is facilitated by releasing the
set screws 126, sliding the rings into the other position, and
retightening the screws. Again referring to FIGS. 9 and 10, with
the release rings secured to the lower position or grooves, as the
completion tool assembly body 102 approaches the support surface
22k the rings cam the lockdown dogs radially outwardly, thereby
unlocking the hanger couplings from the tubing hanger assembly body
22. Thus, when the mandrel subs have been rotated into their locked
position with respect to the tubing hanger couplings (FIG. 10), the
tubing strings can be retrieved from the well by lifting up on the
completion tool assembly 100.
As will be readily apparent, the apparatus of this invention
facilitates running and retrieving a single tubing string as well
as a plurality of strings. Depending upon which string or strings
in a multiple string system is to be connected into, the
corresponding surface tubing string is connected to the tool
assembly 100. Furthermore, in the multiple string system it is of
course not necessary to couple or connect all of the several
surface tubing strings to the lower tubing strings, if such is not
desired.
As will be appreciated from the foregoing description, the
apparatus of this invention provides many advantages. For example,
there are no threads to be stabbed together and made up under
water, thereby increasing reliability and reducing damage
susceptibility of the hanger and running tools, all of which saves
valuable rig time. Another advantage lies in the fact that since
the expanding hanger lands on its own seat in the head, the tubing
load and test pressure load is applied to the head directly rather
than to the casing hangers or pack-offs below these hangers. This
eliminates adding an additional load on the critical lower support
shoulder in the bottom of the head.
Another advantage with the apparatus of this invention is that
multiple strings of tubing may be run simultaneously on drill pipe
in one trip. Furthermore, the complete hanger assembly can be run,
aligned, packed off, tested and locked down all during this single
trip.
Since each tubing string is on its own individual tubing hanger
coupling, and each coupling is individually locked down in the
tubing hanger body, running and/or retrieving individual tubing
strings is possible, as well as individually locking and unlocking
of the coupling for testing purposes. Since there are no threads in
the top of the couplings to be damaged, reliability also is
enhanced with the apparatus of this invention.
When all of the tubing strings are run at one time, the primary
seals on each tubing hanger coupling can be tested at the surface.
This is a very important feature of the present invention, since it
not only indicates what seal is leaking on which tubing hanger
coupling, but it also saves at least one trip into the hole with
the hanger if the seal is leaking.
The use of the completion tool assembly 100 with the tubing hanger
assembly 20 saves many valuable hours of rig time, since it allows
removal and installation of the back pressure valves, setting of
the packers, washing out the well, and any of the work required in
each tubing string. Furthermore, each of the different pay zones
may be flowed through this tool assembly. All information and
condition of each pay zone can be determined, and if there are any
problems they can be worked out before the Christmas tree is run
and the flow lines connected.
Another important feature of this invention is that all functions
performed by the tubing hanger assembly 20 and the other tools are
mechanical, and are independent of up and down motion of the
drilling or production platform. The apparatus of this invention is
economical to manufacture, is of comparatively simple design, and
is ruggedly built to withstand the hammer effect of this up and
down movement, particularly while landing the tubing and the tools.
All of this increases the reliability of the equipment and reduces
the damage thereto, thus saving valuable rig time.
Although the best mode contemplated for carrying out the present
invention has been herein shown and described, it will be apparent
that modification and variation may be made without departing from
what is regarded to be the subject matter of the invention.
* * * * *