U.S. patent application number 09/774295 was filed with the patent office on 2002-01-31 for crossover tree system.
Invention is credited to Baskett, David C., Knerr, Edwin R..
Application Number | 20020011336 09/774295 |
Document ID | / |
Family ID | 22654146 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020011336 |
Kind Code |
A1 |
Baskett, David C. ; et
al. |
January 31, 2002 |
Crossover tree system
Abstract
A subterranean oil or gas well apparatus is provided. The
apparatus includes a single-bore production tubing hanger arranged
concentric with a wellhead. The tubing hanger includes a plurality
of ports and channels arranged about the tubing hanger to give
operators access to the production tubing annulus and provide
chemical injection capability. The ports are closable by a sliding
valve. The apparatus also includes annulus and production
radial-bore stab assemblies between a christmas tree and an
internal crossover assembly. The stab assemblies are extendable and
retractable between the chirstmas tree and the crossover assembly
to allow the retrieval and installation of each independently.
Inventors: |
Baskett, David C.; (Houston,
TX) ; Knerr, Edwin R.; (Houston, TX) |
Correspondence
Address: |
HOWREY SIMON ARNOLD & WHITE LLP
750 BERING DRIVE
HOUSTON
TX
77057
US
|
Family ID: |
22654146 |
Appl. No.: |
09/774295 |
Filed: |
January 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60178845 |
Jan 27, 2000 |
|
|
|
Current U.S.
Class: |
166/368 ;
166/348; 166/86.1; 166/88.4; 166/89.1; 166/90.1; 166/95.1 |
Current CPC
Class: |
E21B 34/02 20130101;
E21B 33/043 20130101; E21B 33/068 20130101; E21B 34/04 20130101;
E21B 33/076 20130101; E21B 33/035 20130101 |
Class at
Publication: |
166/368 ;
166/348; 166/86.1; 166/89.1; 166/88.4; 166/95.1; 166/90.1 |
International
Class: |
E21B 033/043; E21B
033/035; E21B 034/04 |
Claims
What is claimed is:
1. A subterranean oil or gas well assembly comprising: a) a
wellhead; b) a christmas tree coupled to the wellhead; c) a tubing
hanger landed within the wellhead; d) a sliding valve disposed
within the tubing hanger to selectively allow fluid communication
between a first port in the sliding valve and a first port in the
tubing hanger; e) a crossover assembly landed within the tree body,
and; f) a crossover stab disposed within the crossover assembly and
adapted to translate the sliding valve between open and closed
positions.
2. The assembly of claim 1 wherein the tubing hanger is
substantially concentric with the wellhead.
3. The assembly of claim 1 wherein the tubing hanger is a
production tubing hanger with a production tubing suspended
therefrom.
4. The assembly of claim 1 wherein the christmas tree further
comprises a radial annulus bore and a radial production bore.
5. The assembly of claim 4 wherein the Christmas tree further
comprises an integral production bore valve.
6. The assembly of claim 4 wherein the tubing hanger further
comprises an annulus access channel extending between the first
port in the tubing hanger and an annulus, the annulus being defined
between the production tubing and an innermost casing.
7. The assembly of claim 6 further comprising a plurality of
annulus access channels arranged about the tubing hanger and
extending between the annulus and a plurality of first ports.
8. The assembly of claim 7 wherein the plurality of annulus access
channels converge to a common eccentric connector.
9. The assembly of claim 8 wherein the plurality of annulus access
channels reduce in number between the eccentric connector and the
Christmas tree radial annulus bore.
10. The assembly of claim 7 wherein the plurality of annulus access
channels provides an equivalent flow area of at least 1.5
inches.
11. The assembly of claim 6 wherein the crossover stab further
defines the annulus access channel.
12. The assembly of claim 7 wherein the crossover stab further
defines the plurality of annulus access channels.
13. The assembly of claim 1 further comprising a biasing member
disposed between the tubing hanger and the sliding valve.
14. The assembly of claim 13 wherein the biasing member biases the
sliding valve to the closed position.
15. The assembly of claim 11 wherein the crossover assembly further
defines the annulus access channel.
16. The assembly of claim 12 wherein the crossover assembly further
defines the more than one annulus access channel.
17. The assembly of claim 15 wherein the sliding valve facilitates
fluid communication between the annulus access channel defined by
the crossover assembly and the annulus access channel defined by
the crossover stab.
17. The assembly of claim 15 wherein the christmas tree further
defines the annulus access channel.
18. The assembly of claim 4 wherein the crossover assembly further
comprises a radial annulus bore and a radial production bore.
19. The assembly of claim 18 wherein the crossover assembly further
comprises an orientation helix facilitating the alignment of the
crossover radial annulus bore with the tree radial annulus bore and
the crossover radial production bore with the tree radial
production bore.
20. The assembly of claim 19 further comprising an
extendable/retractable production stab, the production stab being
extendable between the tree radial production bore and the
crossover radial production bore.
20a. The assembly of claim 20 wherein both the tree and the
crossover assembly are independently retrievable when the
production stab is retracted.
21. The assembly of claim 20 further comprising an a production
stab mechanism; the mechanism comprising a first shaft, a second
shaft operatively connected to the first shaft by a pair of bevel
gears, and a threaded connection between production stab and the
first shaft.
22. The assembly of claim 21 wherein the mechanism further
comprises an anti-rotation key to prevent the production stab from
rotating with the first shaft.
23. The assembly of claim 19 further comprising an
extendable/retractable annulus stab, the annulus stab being
extendable between the tree radial annulus bore and the crossover
radial annulus bore.
23a. The assembly of claim 23 wherein both the tree and the
crossover assembly are independently retrievable when the annulus
stab is retracted.
24. The assembly of claim 20 further comprising an annulus stab
mechanism; the mechanism comprising a first shaft, a second shaft
operatively connected to the first shaft by a pair of bevel gears,
and a threaded connection between annulus stab and the first
shaft.
25. The assembly of claim 21 wherein the mechanism further
comprises an anti-rotation key to prevent the annulus stab from
rotating with the first shaft.
26. The assembly of claim 4 further comprising a second port in the
sliding valve to selectively allow fluid communication of chemicals
between the second port in the sliding valve and a second port in
the tubing hanger.
27. The assembly of claim 26 wherein the tubing hanger further
comprises a chemical injection channel extending between the second
port in the tubing hanger and a production tubing.
28. The assembly of claim 27 further comprising a plurality of
chemical injection channels arranged about the tubing hanger and
extending between the production tubing and a plurality of second
ports.
29. The assembly of claim 28 wherein the plurality of chemical
injection channels converge to a common eccentric connector.
30. The assembly of claim 29 wherein the plurality of chemical
injection channels reduce in number between the eccentric connector
and a Christmas tree chemical channel.
31. The assembly of claim 28 wherein the plurality of chemical
injection channels provides an equivalent flow area of at least
0.375 inches.
32. The assembly of claim 27 wherein the crossover stab further
defines the chemical injection channel.
33. The assembly of claim 28 wherein the crossover stab further
defines the plurality of chemical injection channels.
34. The assembly of claim 32 wherein the crossover assembly further
defines the chemical injection channel.
35. The assembly of claim 33 wherein the crossover assembly further
defines the one or more chemical injection channels.
36. The assembly of claim 34 wherein the sliding valve facilitates
fluid communication between the chemical injection channel defined
by the crossover assembly and the chemical injection channel
defined by the crossover stab.
37. The assembly of claim 34 wherein the Christmas tree further
defines the chemical injection channel.
38. A subterranean oil or gas well assembly comprising: a) A
wellhead; b) a christmas tree coupled to the wellhead; c) a single
bore tubing hanger landed within the wellhead, the tubing hanger
having a production tubing suspended therefrom; wherein the single
bore tubing hanger further comprises a plurality of first closable
ports therein, the first closable ports facilitating fluid
communication to an annulus defined by the production tubing and an
innermost casing.
39. The assembly of claim 38 wherein the single bore tubing hanger
further comprises a plurality of tubing hanger annulus access
channels extending from at least one of the plurality of first
closable ports to the annulus.
40. The assembly of claim 39 further comprising a plurality of
uphole annulus access channels, wherein the plurality of first
closable ports are correspondingly alignable with the uphole
annulus access channels to facilitate fluid communication between
the uphole annulus access channels and the tubing hanger annulus
access channels.
41. The assembly of claim 40 further comprising a crossover
assembly landed within the tree, wherein the uphole annulus access
channels extend through aligned radial bores in the crossover
assembly and the Christmas tree.
41a. The assembly of claim 41 wherein the uphole annulus access
channels extend longitudinally through the Christmas tree.
42. The assembly of claim 41 wherein the crossover assembly further
comprises a crossover stab and the plurality of first closable
ports further comprises a sliding valve.
43. The assembly of claim 42 wherein the sliding valve is operable
to open and close the first closable ports to selectively allow
fluid communication between the tubing hanger annulus access
channels and the uphole annulus access channels.
45. The assembly of claim 40 wherein the plurality of uphole
annulus access channels converge to a common eccentric connector,
and wherein the number of uphole annulus access channels is reduced
between the eccentric connector and the Christmas tree.
46. The assembly of claim 38 wherein the single bore tubing hanger
further comprises a second plurality of closable ports and a
plurality of tubing hanger chemical injection channels extending
from the second plurality of closable ports, through the tubing
hanger, and to the tubing hanger bore.
47. The assembly of claim 46 further comprising a plurality of
uphole chemical injection channels, wherein the plurality of first
closable ports are correspondingly alignable with the uphole
chemical injection channels to facilitate fluid communication
between the uphole chemical injection channels and the tubing
hanger chemical injection channels.
48. The assembly of claim 47 further comprising a crossover
assembly landed within the tree, wherein the uphole chemical
injection channels extend through aligned longitudinal bores
[define] arranged about the crossover assembly and the Christmas
tree.
49. The assembly of claim 48 wherein the crossover assembly further
comprises a crossover stab and the plurality of second closable
ports further comprises a sliding valve.
50. The assembly of claim 49 wherein the sliding valve is operable
to open and close the second closable ports to selectively allow
fluid communication between the tubing hanger chemical injection
channels and the uphole chemical injection channels.
51. The assembly of claim 46 wherein the plurality of uphole
chemical injection channels converge to a common eccentric
connector, and wherein the number of uphole chemical injection
channels is reduced between the eccentric connector and the
Christmas tree.
52. A method of servicing a subterranean well comprising the steps
of: a) providing a wellhead b) installing a tubing hanger the
wellhead, the tubing hanger comprising: a bore concentric with the
wellhead and a plurality of channels bored longitudinally partially
therethrough, the plurality of channels being spaced around the
circumference of the tubing hanger; C) installing a Christmas tree
with an internal crossover assembly mounted therein onto the
wellhead; wherein the Christmas tree includes an
extendable/retractable stab between radial bores in the crossover
assembly and Christmas tree.
53. The method of claim 52 further comprising the step of
retracting the stab.
54. The method of claim 53 further comprising the step of
retrieving the Christmas tree separately from the tubing
hanger.
55. The method of claim 53 further comprising the step of
retrieving the crossover assembly and the tubing hanger while the
Christmas tree remains connected to the wellhead.
56. The method of claim 52 wherein the tubing hanger further
comprises a plurality of first ports and a plurality of second
ports and a sliding valve for selectively opening and closing the
first and second pluralities of ports.
57. The method of claim 56 further comprising the step of opening
the sliding valve by inserting a crossover stab to position the
sliding valve in an open position.
Description
[0001] This application claims priority of U.S. Provisional
Application No. 60/178,845, filed Jan. 27, 2000, the specification
of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates generally to subsea oil and gas
production methods and apparatus and, more particularly, to a
crossover christmas tree system.
BACKGROUND OF THE INVENTION
[0003] It is conventional practice to complete a subsea well with a
multi bore tubing hanger with tubing suspended below. One bore is a
production bore of between 5 and 10 inches nominal diameter and the
other is a smaller annulus bore of about 2 inches. The tubing
hanger and the associated tubing are run into a subsea wellhead on
a running assembly comprising a tubing hanger running tool and a
multi bore riser until the tubing hanger is landed and sealed in a
wellhead housing. The wellhead carries a blowout preventor (BOP)
stack which is connected to a marine riser through which the tubing
hanger is run.
[0004] This configuration, with the bores side-by-side is typical
because it is relatively simple to seal off the bores in the tubing
hanger. This is done immediately after the tubing hanger has been
landed by running and setting at least one plug into each bore
through the multi bore riser used to install the tubing hanger
using a wireline technique so that the plugs close the bores and
secure the well during the time the tubing hanger is exposed to the
ambient environment.
[0005] Once the plugs are installed, the multi bore riser is
disconnected from the tubing hanger and retrieved to the surface,
after which the BOP stack is disconnected from the subsea wellhead
and retrieved to the surface with the marine riser. At this point,
the tubing hanger is exposed to the ambient environment. The multi
bore riser is re-used to run a Christmas tree which is landed and
locked into the subsea wellhead simultaneously establishing
connections to the tubing hanger. The Christmas tree is installed
using a running assembly comprising the multi bore riser, a safety
package including wireline cutting valves and an emergency
disconnect package which allows the separation of the surface
vessel in the event that it becomes necessary to disconnect the
surface vessel from the wellhead. The multi bore riser leads from
the upper end of the emergency disconnect package to the vessel.
Wirelines can be deployed through the multi bore riser, the safety
package and the Christmas tree in order to retrieve the plugs in
the production bore and the annulus bore. The Christmas tree valves
are then shut while the safety package and the multi bore riser are
retrieved to the surface. The Christmas tree is then capped.
[0006] In deeper water, the viability of such a conventional multi
bore riser is open to question both from structural and commercial
viewpoints. In addition, there are many applications in which a
larger full bore is desirable. Alternatives to multi bore riser
systems utilizing a single bore have been proposed for running and
for operating with a christmas tree but, while they can be used for
plugging the production bore, they suffer from the problem of
providing annulus access with sufficient flow rate capacities to
treat a well--and the lack of annulus flow control.
[0007] Further, in deep water it becomes very difficult to align
side-valve christmas tree ports with the tubing hanger.
[0008] Finally, well drilling and completion operations are very
expensive and often based on per hour rig charges. It is desirable
to complete wells with a few downhole trips as possible to reduce
rig time. In a conventional tubing hanger and christmas tree
assembly, the retrieval of the tubing hanger also requires the
retrieval of the christmas tree. It would be desirable and cost
efficient to find a system that would allow separate retrieval of
the christmas tree and tubing hanger.
[0009] The present invention is directed to eliminating, or at
least reducing the effect of, one or more of the issues raised
above.
SUMMARY OF THE INVENTION
[0010] The invention is directed to a style of Christmas tree
wherein the tubing hanger is landed in the wellhead, and both the
tree and the tubing hanger can be removed independently. This
independent ability to retrieve either the tree or the tubing
hanger, as required, is achieved through the use of a crossover
piece in the tree. When installed, the crossover piece directs the
flow of the production fluid to the production valves outside the
tree, and directs the flow of fluids to or from the tubing annulus.
When the crossover piece is removed, full-bore access through the
tree is available, and the tubing hanger, landed below the tree can
be removed with the tree in place One exemplary embodiment of the
present invention encompasses a subterranean oil or gas well
assembly. Such an embodiment includes: a wellhead; a Christmas tree
coupled to the wellhead; and a tubing hanger landed within the
wellhead. A sliding valve is disposed within the tubing hanger to
selectively allow fluid communication between a first port in the
sliding valve and a first port in the tubing hanger. A crossover
assembly is landed within the tree body, and a crossover stab is
disposed within the crossover assembly and adapted to translate the
sliding valve between open and closed positions.
[0011] A subterranean oil or gas well assembly comprising: a
wellhead; a Christmas tree coupled to the wellhead; and a single
bore tubing hanger landed within the wellhead. The tubing hanger
includes production tubing suspended from it as should be known in
the art. The single bore tubing hanger further includes a plurality
of first closable ports which facilitate fluid communication to an
annulus defined by the production tubing and an innermost
casing.
[0012] These and other features of the present invention are more
fully set forth in the following description of preferred or
illustrative embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The foregoing and other features and aspects of the
invention will become further apparent upon reading the following
detailed description and upon reference to the drawings in
which
[0014] FIG. 1 depicts a crossover tree design in accordance with
one aspect of the invention.
[0015] FIG. 2 depicts the installation/retrieval of the tubing
hanger.
[0016] FIG. 3 depicts the installation/retrieval of the tubing
hanger.
[0017] FIG. 4 depicts the tubing hanger in the wellhead and
temporarily abandoned.
[0018] FIG. 5 depicts running the tree with the tree fully
assembled.
[0019] FIG. 6 depicts a preparation position for retrieving the
tree cap and crossover assembly.
[0020] FIG. 7 depicts the installation/retrieval of the crossover
assembly.
[0021] FIG. 8 depicts full bore access through the tree.
[0022] FIG. 9a-9c depict a view of the alignment mechanism on the
cossover assembly.
[0023] FIG. 10 depicts a hydraulic schematic for the crossover tree
system (CTS) in the production mode.
[0024] FIG. 11 depicts a perspective overview of the CTS.
[0025] FIG. 12 depicts a cross sectional view of the CTS in the
initial sequence positions.
[0026] FIG. 13 depicts a cross sectional view of the CTS in the
retrieve BOP stack/ROV install debris cap sequence.
[0027] FIG. 14 depicts a cross section al view of the CTS in the
tree running sequence.
[0028] FIG. 15a depicts a cross sectional view of the CTS in the
extend the crossover assembly stab into the tubing hanger
sequence.
[0029] FIG. 15b depicts a cross sectional view of the CTS in the
extend the crossover assembly stab into the tubing hanger sequence,
in a second position.
[0030] FIG. 16 depicts a cross sectional view of the CTS in the
retrieve tubing hanger wireline plug/install crossover wireline
plug/retrieve tree running tool/ROV install debris cap
sequences.
[0031] FIG. 17 depicts a cross sectional view of the CTS in the
optional sequence of locking the empty spool body onto the wellhead
with the tree running tool.
[0032] FIG. 18 depicts a cross sectional view of the CTS in the
optional sequences of locking the BOP stack onto the spool body,
running the tubing hanger with a multipurpose running tool, and
installing the tubing hanger wireline plug.
[0033] FIG. 19a depicts a cross sectional view of the CTS in the
optional sequence of running the crossover assembly with the
multi-purpose running tool in a first position.
[0034] FIG. 19b depicts a cross sectional view of the CTS in the
optional sequence of extending the crossover assembly stab into the
tubing hanger in a second position.
[0035] FIG. 20a depicts a cross sectional view of the CTS in the
optional sequence of extending the crossover assembly stab into the
tubing hanger in a first position.
[0036] FIG. 20b depicts a cross sectional view of the CTS in the
optional sequence of extending the crossover assembly stab into the
tubing hanger in a second position.
[0037] FIG. 21 a cross sectional view of the CTS in the optional
sequences of retrieving the tubing hanger plug, installing
crossover plugs, retrieving the BOP stack, and ROV installing the
debris cap.
[0038] FIG. 22 depicts a combination detail of the side stabs.
[0039] FIG. 23 depicts the tubing hanger shuttle valve detail.
[0040] FIG. 24 depicts the tubing hanger shuttle valve detail in
cross section.
[0041] FIGS. 25a-25c depict details of the annulus flow paths.
[0042] FIG. 26 depicts a cross-sectional top view of the CTS.
[0043] FIG. 27 depicts a top view of the CTS and retractable stab
mechanism.
[0044] FIG. 28 depicts a detail of the bevel gears of the
retractable stab mechanism.
[0045] FIG. 29 depicts a perspective view of the apparatus
according to FIG. 27.
[0046] FIG. 30 is an alternative embodiment of the christmas
tree.
[0047] FIG. 31 depicts a cross sectional view of the CTS with a
safety tree.
[0048] FIG. 32 depicts a cross sectional view of the CTS in the
crossover assembly installation sequence.
[0049] FIG. 33 depicts a cross sectional view of the
installation/retrieval of the tree.
[0050] FIGS. 34-35 depict a detail of the crossover assembly/hanger
interface.
[0051] FIG. 36 depicts a perspective view of the annulus stab
mechanism.
[0052] FIGS. 37-38 depict details of the electrical interface
between the crossover assembly and the tubing hanger.
[0053] FIG. 39 depicts a multiple use running tool.
[0054] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof have been shown
by way of example in the drawings and are herein described in
detail. It should be understood, however, that the description
herein of specific embodiments is not intended to limit the
invention to the particular forms disclosed, but on the contrary,
the intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the invention
as defined by the appended claims.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0055] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. It will of
course be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, that will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming, but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure.
[0056] Previous attempts to develop a tree with the advantages of a
crossover tree have resulted in designs wherein a false or dummy
tubing hanger is installed in the tree. U.S. Pat. No. 5,372,199 is
one example of such a design. Similar designs were offered for sale
by National Oilwell prior to the date of the cited patent. However,
such designs were cumbersome and required additional steps to
retrieve specific components. The current invention overcomes this
and other limitations of the prior art trees.
[0057] Turning now to the Figures, and in particular FIG. 1, a
Crossover Christmas tree 2 with a tubing hanger 4 installed within
a wellhead 6 in accordance with one embodiment of the invention is
disclosed. The assembly shown in FIG. 1 represents one embodiment
of the crossover tree system and the associated assembly fully
installed. Tree 2 is connected to a wellhead 6 by a tree connector
3. As shown in FIG. 10, tree connector 3 can be hydraulically
actuated such that a lock down ring 58 mates with an exterior
profile on wellhead 6. Other types of tree connectors generally
known in the art can be adapted to couple the tree 2 to the
wellhead 6.
[0058] The assembly shown in FIG. 1 includes tubing hanger 4, which
is installed substantially concentrically within wellhead 6. In one
embodiment, tubing hanger 4 is a concentric tubing hanger, seven
inches in diameter, but may range in size as required for a
particular field development. Eccentric or dual bore tubing hangers
may be used, in other embodiments not shown. Tubing hanger 4 rests
on a shoulder 8 of wellhead 6, and the annulus between then tubing
hanger 4 and the wellhead 6 is sealed. A tubing hanger lock down
ring 56 helps secure tubing hanger 4 within tree 2. The lower end
of tubing hanger 4 suspends a downhole tubing 7 (shown
schematically in FIG. 10) to facilitate a production flow from
wellbore to surface when the downhole safety valve 9 is open.
[0059] A crossover assembly 10 is disposed within the bore of the
crossover tree 2 such that the assembly bore 11 is substantially
coaxial with the bore 5 in the tubing hanger 4. A crossover stab 12
sealably mates with tubing hanger 4. The annulus between the
crossover assembly 10 and the tree 2 is sealed, for example by
crossover seal 40 disposed between the crossover assembly 10 and
tree 2.
[0060] In the embodiment shown in FIG. 1, crossover assembly 10 and
crossover stab 12 are installed substantially concentrically with
hanger 4, with the distal end of crossover stab 12 extending
partially through the interior of hanger 4. As seen more distinctly
in FIGS. 15A and 15B, a plurality of seals 14 seal between hanger 4
and crossover stab 12. Disposed between crossover stab 12 and
hanger 4 is a sliding valve 16, which may also be called a shuttle
valve. Sliding valve 16 is shown in the down or operating position
in FIG. 1 (the details of sliding valve 16 are discussed below). In
some embodiments a biasing element, such as a compressed spring,
may be disposed in the area labeled 15 in the FIG. 1 embodiment to
bias the sliding valve 16 to a closed (up) position wherein ports
such as 17 and 17a (as shown more clearly in FIGS. 15A and 15B) are
misaligned. In the embodiment shown sliding valve 16 is actuated
between open and closed position by the application of hydraulic
pressure to space 15.
[0061] Referring to FIGS. 23 and 24, sliding valve 16 may include a
body 156 with opposing ports or bores 17 and 19. In the embodiment
of FIG. 1, bore 17 is an annulus access bore or port. Bore or port
19 is shown in the embodiment of FIGS. 23 and 24 as a chemical
injection bore. Body 156 of valve 16 may exhibit flat machined
faces 152 and 154 on the outer diameter of the body at bores 17 and
19. A second annulus port 17a with a sealing face meets flat
machined face 152. Port 17a is attached to a spacer 164 and is in
fluid communication with annulus access bore 18 via a plurality of
holes 166 arranged about the circumference of the spacer. A
plurality of seals (not shown) seal between spacer 164 and second
port 17a.
[0062] Adjacent to spacer 164 opposite the port 17a is an
adjustable plug 168. A plurality of seals (not shown) on adjustable
plug 168 inhibits leakage past the plug. Adjustable plug 168,
spacer 164, and port 17a are arranged within a radial bore 170 in
tree 2. Adjustable plug 168 may have a hex recess 172 to allow an
operator to adjust the compression between machined face 152 on and
the sealing face of port 17a.
[0063] As shown in the figures, valve 16 may include a chemical
injection bore or port 19. Chemical injection port 19 includes a
chemical injection adjustable plug 174 adjacent a chemical
injection spacer 176. Chemical injection spacer 176 includes a
plurality of holes 178 to facilitate fluid communication with a
chemical injection bore 23 in tubing hanger 4. Chemical injection
adjustable plug 174 may include a plurality of seals (not shown) to
inhibit leakage past the plug. Chemical injection spacer 176
attaches to chemical injection second port 19a. Chemical injection
second port 19a includes a sealing face which meets flat machined
surface 154. Chemical injection adjustable plug 174, spacer 176,
and second port 19a are arranged within a second radial bore 178 in
tree 2. Chemical injection adjustable plug 174 may have a hex
recess (not shown) to allow an operator to adjust the compression
between machined face 154 on and the sealing face of second port
162.
[0064] As shown in FIG. 23, shuttle valve 16 is in a first or
closed position. A first plurality of seals 180 inhibit fluid
leakage between body 156 and hanger 4. A second plurality of seals
182 may further inhibit fluid leakage. The seals may include a
primary metal-to-metal seal and secondary elasomer or polymer seal,
with retainers in between. In the first position (shown in FIGS. 23
and 24), annulus access bore 17 is not aligned with second annulus
access port 17a. Likewise, chemical injection bore 19 is not
aligned with second chemical injection port 19a. However, in some
embodiments, one or both of annulus access bore 17 and chemical
injection bore 19 is in fact lined up with its associated second
port (17a and 19a) in the first position.
[0065] Crossover stab 12 includes an annulus access channel 18
facilitating fluid communication to a downhole annulus 21 between
the production tubing 7 and the innermost casing (tubing annulus
not shown). Annulus access channel 18 is substantially longitudinal
through tubing hanger 4, crossover stab 12, crossover assembly 10,
and tree 2. Annulus access channel 18 is typical of a plurality of
annulus access channels 18 shown in cross-section in FIGS. 25a-25d.
In the section shown in FIGS. 25a and 25b, the first portion of
annulus access channels 18 are designated 18a and are arranged
interior to the crossover assembly between the interior wall 200
and the exterior diameter 202. The number and size of annular
access channels 18a is a function of the flow capability desired.
Typically the equivalent flow area of the combination of annulus
access channels 18a is at least 1.5 inches, however this equivalent
flow area may vary according to the particular operation. The
equivalent flow area may be determined by operational standards to
provide sufficient flow to, for example, kill a well with heavy
fluids in the event of an emergency. Annulus access channels 18a
converge to a common eccentric connector 204 which provides for
fluid communication from each of annulus access channels 18a to
continue through another plurality of larger annulus access
channels, for example the three larger annulus access channels 118b
shown in FIGS. 25a , 25c, and 25d. FIG. 25c is a view in the upward
direction of the section shown in FIG. 25a, which is in the
opposite direction of same section shown in FIG. 25b. Annulus
access channels 18a and 18b advantageously provide an equivalent
flow area to operationally manage the well while also allowing for
a single bore tubing hanger. Similar channels may be part of the
crossover tree system to provide for chemical injection downhole,
or to provide communication with downhole equipment such as
pressure and temperature sensors. Those skilled in the art will
appreciate that the disclosure of the annulus communication system
is applicable to many other types of downhole communication. In the
exemplary embodiment shown, chemical channels 23 extend through
crossover assembly 10 to facilitate chemical injection into
production tubing 7 in much the same way as annulus access channels
18. In the embodiment shown, the plurality of chemical channels 23
provide a minimum equivalent flow area of 0.375 inches to provide
adequate flow to the production bore as necessary. It will be
understood by one of skill in the art with the benefit of this
disclosure, however, that other equivalent flow areas deviating
substantially in either direction from 0.375 inches can be obtained
as required for the particular application.
[0066] One or more annulus valves 20 may isolate the sections of
annulus access channel 18 between the tree 2 and the crossover
assembly 10. Annulus valve 20 is shown in FIG. 1 exterior to the
tree body, but it may be located anywhere along annulus access
channel 18. A second annulus valve 21 may also be used as shown in
FIGS. 1 and 16. While the annulus valves and piping are shown with
flanged connections to the tree 2, other types of connections can
be substituted, or portions of the annulus piping or valves may be
integral to the tree body as shown in FIG. 30.
[0067] Annulus access channel 18 extends through a radial bore 32
in tree 2, continues outside the body of tree 2, then re-enters the
body of tree 2 and continues substantially longitudinal with the
proximal end of tree 2. A retractable radially extending annulus
stab assembly 36 extends between radial annulus bore 32 in tree 2
and crossover assembly 10. The retractability of an annulus stab 35
advantageously allows for independent installation and retrieval of
tubing hanger 4, crossover assembly 10, and the tree 2. Annulus
access channel 18 terminates at a proximal annulus port 34 which
facilitates fluid communication between the tubing annulus and the
surface. While annulus port 34 is shown above the crossover
assembly 10, it may be located adjacent or below the crossover
assembly.
[0068] Annulus stab 35 may be operable by hydraulic or electric
actuation, or it may be mechanically operated. In the embodiment
shown, annulus stab 36 is operated mechanically. The details of the
annulus stab assembly 36 are found in FIGS. 26-29. For example,
annulus stab 35 may be operable by ROV (not shown). The ROV may be
a standard remote operated vehicle or it may be any other remotely
operated vehicle. The ROV provides rotational movement to annulus
stab mechanism 210 to extend and/or retract annulus stab 35 between
crossover assembly 10 and tree 2. Annulus stab mechanism 210 shown
in FIGS. 26-29 includes first and second shafts 212 and 214
extending from the annulus stab mechanism. Distal end 216 of second
shaft 214 is adapted to connect to an ROV. Proximal end 218 of
second shaft 214 is operatively connected to a pair of bevel gears
220 and 222 which are approximately 90 degrees out of phase with
one another. Therefore, rotation of second shaft 214 is translated
90 degrees to rotate first shaft 212. In an alternative embodiment,
first shaft 212 is rotated directly without the use of a second
shaft or set of gears. First shaft 212 is threadedly connected to
annulus stab 35. Annulus stab 35 includes an anti-rotation key 224
which prevents the annulus stab from rotating with first shaft 212.
Therefore, as first shaft 212 rotates, the rotational movement is
translated via the threaded connection with annulus stab 35 into
strictly axial movement of the annulus stab. Upon connection
between second shaft 214 and the ROV, rotation of the second shaft
may ultimately accomplish the extension or retraction of annulus
stab 35 into and/or out of engagement with crossover assembly 10.
Alternatively, annulus stab 35 may be hydraulically or electrically
extended and retracted (not shown). FIG. 36 shows in perspective
view the annulus stab mechanism 36.
[0069] Crossover stab 12 also includes a downhole safety valve
control assembly 92 which is in communication with a safety valve
access channel 94 through crossover stab 12. As shown in more
detail in FIG. 15A, gallery seals 14 prevent the flow of hydraulic
fluid associated with safety valve access channel 94 substantially
above or below the channel. When the sliding valve 16 is in the
open or down position as shown in FIG. 15B, channel 94 aligns with
a channel in the tubing hanger 4 (not shown) to provide hydraulic
communication downhole. When the sliding valve 16 is in the closed
or up position as shown in FIG. 15A, channel 94 is not aligned with
the channel in the tubing hanger 4 (not shown) and hydraulic
communication is not present (putting the downhole safety valve
into its fail-closed position). As such, downhole safety valve
control assembly 94 and safety valve access channel 94 allow the
operator to open or close the downhole safety valve 9 (shown in
FIG. 10) as necessary.
[0070] A crossover seal 38 seals the annulus between crossover
assembly 10 and tree 2 and may serve as a second barrier to any
possible leaks across crossover seal 40 in crossover assembly 10.
Seal 38 may be comprise metal-to-metal sealing elements or may
comprise resilient sealing elements.
[0071] In the embodiment of FIG. 1, a wireline plug 24 is disposed
within crossover assembly 10. A second wireline plug 26 is also
disposed within crossover assembly 10. Wireline plugs 24 and 26
provide a multi seal between the production fluids entering tubing
hanger 4, and cap assembly 42. Plugs 24 and 26 may comprise
mechanical or hydraulic plugs, may be retrievable using wireline,
coiled tubing, or pipe, or may be valves or other closures which
are known in the art. In the embodiments of FIGS. 10 through 21,
both closures are installed in crossover assembly 10.
[0072] At least a portion crossover assembly 10 and tubing hanger 4
are located radially interior to tree 2. Crossover assembly 10 has
associated lock down ring 30 to position the crossover assembly
securely within tree 2 and to prevent dislocation after the
assembly is landed and locked.
[0073] In one embodiment, tree 2 includes a radially extending
production stab assembly 44. Production stab assembly 44 includes a
tree bore 46, which is aligned with a crossover bore 48 in
crossover assembly 10. A production stab 50 extends between
crossover bore 48 and tree bore 46 in the position shown in FIG. 1.
A plurality of production seals 52 seal between the production stab
50 and bores 46 and 48. Production stab 50 is retractable as
described below. One or more production valves, such as valve 54
shown, may be attached to production stab assembly 44 to control
the flow of produced hydrocarbons. FIG. 10 shows a general
arrangement including production master valve (PMV) 54 and
production wing valve (PWV) 99. One or more of valves 54 and 99 may
be flanged and bolted to the tree 2, as is shown for valve 54 in
FIG. 1, or one or more of the valves may be integral to a valve
block or to the tree body as shown in FIG. 30. The embodiment of
FIG. 2 shows production valve 54 adjacent production stab assembly
44, but it will be understood that production valve 54 may be
integral to the production stab assembly as shown in FIG. 30.
[0074] Similar to annulus stab 35, production stab 50 may be
operable by hydraulic or electric actuation, or it may be
mechanically operated. In the embodiment shown, production stab 50
is operated mechanically. For example, production stab 50 may be
operable by an ROV (not shown). The ROV provides rotational
movement to a production stab mechanism 230 to extend and/or
retract production stab 50 between crossover assembly 10 and tree
2. Production stab mechanism 230 shown in FIGS. 26-29 includes
first and second shafts 232 and 234 extending from the production
stab mechanism. Distal end 236 of second shaft 234 is adapted to
connect to an ROV. Proximal end 238 of second shaft 234 is
operatively connected to a pair of bevel gears 220 and 222 which
are approximately 90 degrees out of phase with one another.
Therefore, rotation of second shaft 234 is translated 90 degrees to
rotate first shaft 232. In an alternative embodiment, first shaft
232 is rotated directly without the use of a second shaft or set of
gears. First shaft 232 is threadedly connected to production stab
50. Production stab 50 includes an anti-rotation key 240 which
prevents the production stab from rotating with first shaft 232.
Therefore, as first shaft 232 rotates, the rotational movement is
translated via the threaded connection with production stab 50 into
strictly axial movement of the production stab. Upon connection
between second shaft 234 and the ROV, rotation of the second shaft
may ultimately accomplish the extension or retraction of production
stab 50 into and/or out of engagement with crossover assembly 10.
Alternatively, production stab 50 may be hydraulically or
electrically extended and retracted (not shown). Second shafts 234
and 214 may extend through a standard ROV panel 242, along with an
alignment pin shaft 244. FIG. 35 shows in perspective view the
annulus stab mechanism 36.
[0075] With the assembly as shown in FIG. 1, production fluids may
enter tubing hanger 4 from the wellbore and continue through a
portion of crossover assembly 10. The production fluids are then
directed through crossover bore 48 as wireline plug 26 inhibits
further progression up through crossover assembly 10. Production
fluids continue through tree bore 46 and into the radially
extending production stab assembly 44. When production valve 54 is
open, production fluids then continue into a flow line 246 for
further transportation to a desired location. An operator also has
access, according to the embodiment shown in FIG. 1, to the annulus
of the wellbore tubing through annulus access channel 18. The
access to the annulus may be important, for example, to allow an
operator to circulate fluids, to relieve pressure in the annulus,
or to bullhead the well for example. Should there be any leakage
past either wireline plug 26 or crossover seal 40, a redundant set
of seals on wireline plug 24 and seal 41 prevent further leaking. A
perspective view of the apparatus of FIG. 1 is shown in FIG.
38.
[0076] Referring next to FIGS. 2 and 2b, one of many sequences of
installation, retrieval, or workover that are possible in
accordance with the invention is described. FIGS. 2, 2b and 12
depict the installation and/or retrieval of tubing hanger 4 within
wellhead 6. Generally, tubing hanger 4 is installed while a blowout
preventor (BOP) stack 60 is attached to wellhead 6 or to the tree
2. BOP stack 60 is conventional and well known to one of skill in
the art with the benefit of this disclosure. Referring to FIG. 3,
with BOP stack 60 in place, tubing hanger 4 and crossover stab 12
are inserted into or retrieved from wellhead 6. Crossover stab 12
is in the working or down position as shown in FIGS. 1 and 2b.
Tubing hanger 4 and crossover stab 12 are attached to a multi
purpose running tool 62. Multi purpose running tool 62 is also
shown in FIG. 39. In FIG. 2, however, the christmas tree 2 has also
been installed and only the tubing hanger has been installed
without the crossover stab. In some embodiments tubing hanger 4
includes tubing hanger collet fingers 64, which are engaged with a
collet 66 at the distal end of multi purpose running tool 62 during
installation and/or retrieval of tubing hanger 4. When tubing
hanger 4 is being installed, the hanger continues downhole via
multi purpose running tool 62 until it engages wellhead shoulder 8.
When tubing hanger 4 engages wellhead shoulder 8, tubing hanger
lockdown ring 56 locks the hanger in place and multi purpose
running tool 62 may be returned to surface.
[0077] Referring next to FIGS. 3 and 13, with tubing hanger 4
positioned within wellbore 6, crossover stab 12 is removed,
allowing the sliding valve 16 to be in the closed or up position. A
wireline plug 68 or other closure is set inside the tubing hanger
through BOP stack 60. The BOP stack is then retrieved and a
temporary abandonment/debris cap assembly 42 is installed and
attached to wellhead 6 in the position shown in FIGS. 3 and 13.
Tubing hanger sliding valve 16 is in the up or sealed off position
in this sequence to prevent flow through the annular access or
chemical injection porting, as the assembly awaits the installation
of tree 2.
[0078] Referring next to FIG. 5, the temporary abandonment/debris
cap assembly 42 and wireline plug 68 have been removed and fully
assembled tree 2 is installed. Tree 2 is run on tree running tool
70 with crossover assembly 10, crossover stab 12, and plug 24 in
place inside tubing hanger 4. Crossover stab 12 is in the up or
running position and tubing hanger sliding valve 16 is in the up or
sealed position, which seals off the tubing annulus communication,
as well as other downhole communication such as the safety valve 9
and injection lines at the sliding valve 16. Tree running tool 70
is attached to the exterior of tree body 2 via tree running tool
lock down ring 72. The complete tree assembly 2 is run until tree
connector lock down ring 58 engages with wellbore 6 and the tree is
secured in the position shown in FIG. 5.
[0079] Referring next to FIG. 6, tree assembly 2 is shown in
sequence wherein preparation is made for retrieving crossover
assembly 10. The preparation for retrieval of crossover assembly 10
comprises reinstalling BOP stack. In the sequence shown in FIG. 6,
BOP stack 60 is being run in and lock down ring 74 has not yet
engaged tree 2. In FIG. 7, BOP 60 is installed and connected to the
proximal end of tree 2. BOP lock down rings 74 are engaged with
tree 2 at the proximal end of the tree. If any wireline plugs have
been set in the crossover assembly they may be retrieved and
wireline plug 68 inside tubing 4 is set, in preparation for
retrieving crossover assembly 10.
[0080] As shown in FIG. 7, the multi purpose running tool 62 may be
inserted through BOP stack 60 to retrieve crossover assembly 10.
Multi purpose running tool is shown attached to crossover assembly
10. In the embodiment shown in FIG. 7, the attachment between
crossover assembly 10 and multi purpose running tool 62 is
facilitated by an crossover assembly collet finger 76 engaged with
collet 66 of multi purpose running tool 62. Crossover assembly
collet finger 76 may be mounted on an exterior surface of crossover
assembly 10 as shown in the Figures. With the multi purpose running
tool 62 attached to crossover assembly 10, the running tool and
tree cap may be either retrieved or installed. When crossover
assembly 10 is installed, its operational position relative to tree
2 is facilitated by crossover assembly lock down ring 28, which is
engageable with tree 2 as discussed above. In addition, during
installation and retrieval of crossover assembly 10, crossover stab
12 is in the up or installation/retrieval position as shown.
[0081] The engagement of collet fingers 76 and collet 66 constitute
one mechanism of attachment between crossover assembly 10 and
running tool 62. Other alternative attachment mechanism may be
used. During installation and retrieval of crossover assembly 10,
sliding sleeve 16 is in the up or installation/retrieval position
as shown. In addition, production stab 50 and annulus stab 35 are
retracted before installation or retrieval proceeds. The retraction
of the production stab 50 and annulus stab 35 is accomplished by a
mechanical ROV in the preferred embodiment, but other means for
actuation including, but not limited to, hydraulic and/or electric,
may be used. [If a hydraulic system is used, production stab 50 and
annulus stab 35 may be normally biased to the retracted positions
with the extension of each accomplished by hydraulic fluid.
Alternatively, production stab 50 and annulus stab 35 may be
motivated to their respective extended and retracted positions with
hydraulic pressure without a bias. Hydraulic control lines (not
shown) extending to sealed void areas between the stab assembly 44
and the production stab 50, or between the annulus stab 35 and the
annulus piping, are one means of such control. In a preferred
embodiment, one set of hydraulic lines will control both sets of
stabs. Preferrably, production stab 50 and annulus stab 35 may be
actuated by mechanical means such as the production stab mechanism
230. After installation, and after crossover assembly 10 is
positioned in the tree with crossover bore 48 aligned with tree
bore 46, annulus stab 35 and production stab 50 are extended to the
position shown in FIG. 1.
[0082] Referring next to FIG. 8, the tree assembly is shown without
crossover assembly 10. In this configuration, which may be before
installation of crossover assembly 10, or after retrieval of the
same, full bore access to the wellbore through tubing hanger 4 is
available. Full bore access advantageously enables workover of the
well or other repairs and maintenance. Tubing hanger sliding valve
16 is in the up or sealed position in full bore access position to
seal off access to the tubing annulus (not shown). Wireline plug 68
is also in place within tubing hanger 4 in this configuration. In
order to accomplish the installation and/or retrieval of the
crossover assembly, however, the production stab 50 and annulus
stab 35 must first be retracted as shown.
[0083] Referring next to FIG. 31, the crossover assembly 10 is
being installed through BOP 60.
[0084] Referring next to FIG. 32, crossover assembly 10 has been
installed by multi purpose running tool 62 and crossover stab 12
extended to force sliding valve 16 into the open position. Wireline
plugs 24 and 26 may then be set in anticipation of production.
Alternatively, in a retrieval operation, wireline plugs may be
retrieved and crossover assembly 10 and crossover stab 12 may be
retrieved as well.
[0085] Referring next to FIG. 33, an installation/retrieval
sequence for christmas tree 2 is shown. Christmas tree 2 is shown
running on a tree running tool 250. Tree running tool 250 may be
used similarly to retrieve tree 2.
[0086] Referring next to FIGS. 34 and 35, a detail of the interface
between crossover assembly 10 and tubing hanger 4 is shown. The
flow path of annulus access channels 18 are more clearly seen as it
extends through the crossover assembly and to the tubing hanger via
an annulus cavity 252. Likewise, the flow path of the chemical
injection channels 23 are more clearly seen as they extend through
the crossover assembly and to the tubing hanger via a second cavity
254. Sliding valve 16 facilitates and/or prevents the flow of
through all of the annulus access channels 18 and chemical
injection channels 23.
[0087] In some embodiments of the present invention the engagement
between crossover assembly 10 and tubing hanger 4 includes one or
more electrical contacts 260. As shown in FIGS. 37-38, the
electrical contacts may be separated isolated by a number of seals
262.
[0088] Referring next to FIGS. 9a-9c, it can be seen that an
integral orientation helix 82 may be included on crossover assembly
10. Orientation helix 82 shaped such that upon installation of
crossover assembly 10, the assembly is directed into the correct
orientation position with crossover bore 48 aligned with tree bore
46. Orientation helixes and their use are well known in the art.
Alignment pin 270 extending through tree 2 engages helix 82 and
directs the crossover assembly to the desired orientation.
[0089] The present invention thus advantageously facilitates a
horizontal tree and tubing hanger to each be independently
retrievable with full-bore wellhead access.
[0090] Referring next to FIG. 10, a hydraulic schematic for the
crossover tree system (designated CTS in FIGS. 10 through 21) in
accordance with one embodiment of the invention in the production
mode is disclosed. The production system valving may include a
production master valve 54 and optionally a production wing valve
99 to facilitate control of the production fluids from the
wellbore. Access to the tubing annulus may also be facilitated by
the valving scheme shown in FIG. 10. An annulus master valve 20
facilitates primary access to the annulus. An annulus wing valve 21
may allow the flow of annular fluids to an external connection or
may be the means by which annular fluids are introduced through an
external connection. In series with the annular master valve may be
an annulus circulation valve 100 to regulate flow and/or pressure
in the annulus and provide a communication with the longitudinal
throughbore of tree 2. In addition, a crossover valve 102 may allow
the operator to open or close fluid communication between the
production line and the annulus.
[0091] Referring next to FIG. 12, one of a second set of sequences
in accordance with the invention is shown. FIG. 12 depicts the
installation and/or retrieval of tubing hanger 4 within wellhead 6.
Generally, tubing hanger 4 is installed while a blowout preventor
(BOP) stack 60 is attached to wellhead 6. BOP stack 60 is
conventional and well known to one of skill in the art. With BOP
stack 60 in place, tubing hanger 4 and crossover stab 12 are
inserted into or retrieved from wellhead 6. Crossover stab 12 is in
the working or down position as shown in FIGS. 1 and 2. Tubing
hanger 4 and crossover stab 12 are attached to multi purpose
running tool 62. In some embodiments tubing hanger 4 includes
tubing hanger collet fingers 64, which are engaged with a collet 66
at the distal end of multi purpose running tool 62 during
installation and/or retrieval of tubing hanger 4. When tubing
hanger 4 is being installed, the hanger continues downhole via
multi purpose running tool 62 until it engages wellhead shoulder 8.
When tubing hanger 4 engages wellhead shoulder 8, tubing hanger
lockdown ring 56 locks the hanger in place and multi purpose
running tool 62 may be returned to surface. In a preferred
embodiment, tubing hanger 4 is a non-oriented tubing hanger,
although oriented tubing hangers may be provided.
[0092] Referring next to FIG. 13, with tubing hanger 4 positioned
within wellbore 6, crossover stab 12 is removed and a wireline plug
68 or other closure is set inside the tubing hanger through BOP
stack 60. The BOP stack may be retrieved and a temporary
abandonment/debris cap assembly 42 may be installed and attached to
wellhead 6 in the position shown in FIG. 13. Tubing hanger sliding
valve 16 is in the up or sealed off position in this sequence to
prevent flow through the annular access or chemical injection
porting, as the assembly awaits the installation of tree 2.
[0093] Referring next to FIG. 14, the temporary abandonment/debris
cap assembly 42, wireline plug 68 remains in place, and fully
assembled tree 2 is installed. Tree 2 is run on tree running tool
70 with internal tree cap 22, crossover assembly 10, and crossover
stab 12 inside tree body 2. Plugs 24 and 26 are not installed
inside tree body 2 in this sequence. Crossover stab 12 is in the up
or running position and tubing hanger sliding valve 16 is in the up
or sealed position, which seals off the tubing annulus (not shown)
at the valve. Tree running tool 70 is attached to the exterior of
tree body 2 via tree running tool lock down ring 72. The complete
tree assembly 2 is run until tree lock down ring 58 engages with
wellbore 6 and the tree is secured in the position shown in FIG.
14.
[0094] Referring next to FIGS. 15a and 15b, a detailed view of
crossover stab assembly 12 is shown. In FIG. 15a, crossover stab 12
is in the up or running position and tubing hanger sliding valve 16
is in the up or sealed position, which seals off the tubing annulus
communication, chemical injection lines, and the downhole safety
valve hydraulics as tree 2 is installed.
[0095] For example, FIG. 15a shows that in the up or running
position, first ports 17 (the annulus communication ports) in
sliding valve 16 do not align with first ports 17a in tubing hanger
4. It will be understood to those of skill in the art that port 17a
in the tubing hanger 4 may be one of several ports radially spaced
around the tubing hanger, and extend down through the tubing hanger
body to the tubing annulus. First ports 17a in tubing hanger 4,
which may be arranged about the inner circumference of the tubing
hanger, are preferably arranged equidistantly around the inner
circumference of tubing hanger 4. By sizing the ports properly and
selecting the appropriate number of ports first ports 17a provide a
fluid communication path with sufficient flow area to the tubing
annulus. The number of ports and/or the size of the ports may vary
depending on the use and field characteristics.
[0096] Similarly, second ports 19a may provide a fluid
communication path for chemical injection lines downhole for
facilitating chemical insertions into the production and/or the
formation. It will be appreciated that any number of porting
arrangements and communications downhole may be provided.
[0097] The communications paths facilitated by first ports 17a and
second ports 19a are, however, sealed off from respective first and
second ports 17 and 19 in FIG. 15a. When tree 2 has been set,
crossover stab 12 may be extended into tubing hanger 4 to the
position shown in FIG. 15b until first ports 17 and second ports 19
in valve 16 align with first ports 17a and second ports 19a in
tubing hanger 4, respectively. Alignment is accomplished when the
shoulder 13 of shuttle valve 16 contacts ledge 90 of tubing hanger
4.
[0098] FIG. 16 depicts the next sequence in which the tubing hanger
plug 68 is retrieved on wireline and crossover wireline plugs 24
and 26 are installed as shown. Tree running tool 70 (not shown in
FIG. 16) may then be retrieved and an ROV may install the temporary
abandonment/debris cap 42.
[0099] An optional set of sequences are shown in FIGS. 17-21 and
are described as follows. Referring to FIG. 1, tree 2 may be run
with an empty body on tree running tool 70. In this sequence, the
internal tree cap, crossover assembly 10, crossover stab 12, and
plugs 24 and 26 are not in place inside tree body 2. Tree 2 is
locked onto wellhead 6 as described previously.
[0100] Referring next to FIG. 18, BOP stack 60 is run and locked
onto tree 2 via BOP lockdown ring 74 which mates with matching
profile 95 on tree 2. Tubing hanger 4 may be run in on multi use
running tool 62 as described above. No orientation apparatus is
required with the running of the tubing hanger. A wireline plug 68
may be installed in the tubing hanger (not shown in FIG. 18).
[0101] Referring next to FIGS. 19a and 19b, crossover assembly 10
may be run on multi use running tool 62. Crossover assembly 10
self-orients within tree 2 with the aid of an orientation helix as
described above and shown in FIG. 9. As shown in FIG. 19b, which is
a detail of the multi use running tool 62, the crossover stab 12
(not shown in FIG. 19b) may be replaced by a bore protector
[0102] FIGS. 20a and 20b, similar to FIGS. 15a and 15b, show the
extension of crossover stab 12. In FIG. 20a, crossover stab 12 is
in the up or running position and tubing hanger sliding valve 16 is
in the up or sealed position, which seals off the tubing annulus
(not shown) at the valve as tree 2 is installed. FIG. 20a shows
that in the up or running position, upper ports 17 and lower ports
19 in sliding valve 16 do not align with upper ports 17a and lower
ports 19a in tubing hanger 4. Upper ports 17a in tubing hanger 4,
which may be arranged about the inner circumference of the tubing
hanger, are preferably arranged equidistantly around the inner
circumference of tubing hanger 4. Upper ports 17a provide a fluid
communication path to the tubing annulus (not shown). Lower ports
19a provide a fluid communication path to the downhole tubing (not
shown) for facilitating chemical insertions into the production
formation. The communications paths facilitated by upper ports 17a
and lower ports 19a are, however, sealed off from respective upper
and lower ports 17 and 19 as shown in FIG. 20a. When tree 2 has
been set, crossover stab 12 may be extended to the position shown
in FIG. 20b until upper ports 17 and lower ports 19 in valve 16
align with upper ports 17a and lower ports 19a in tubing hanger 4,
respectively. Alignment is accomplished when the shoulder 13 of
shuttle valve 16 contacts ledge 90 of tubing hanger 4.
[0103] Referring next to FIG. 21, the CTS is shown completely
installed. The optional sequence leading up to FIG. 21 as shown
includes retrieving tubing hanger plug 68 (not shown in FIG. 21),
installing crossover plugs 24 and 26 on wireline, retrieving BOP
stack 60 (not shown in FIG. 21) and installing temporary
abandonment/debris cap 42.
[0104] In view of the above disclosure, one of ordinary skill in
the art should understand and appreciate that one illustrative
embodiment of the present invention includes a subterranean oil or
gas well assembly that includes: a wellhead; a Christmas tree
coupled to the wellhead; and a tubing hanger landed within the
wellhead. A sliding valve is disposed within the tubing hanger to
selectively allow fluid communication between a first port in the
sliding valve and a first port in the tubing hanger. A crossover
assembly is landed within the tree body, and; a crossover stab is
disposed within the crossover assembly and adapted to translate the
sliding valve between open and closed positions. In a preferred
version of the present illustrative embodiment, the tubing hanger
is substantially concentric with the wellhead. Preferably the
tubing hanger is a production tubing hanger with a production
tubing suspended therefrom. The tubing hanger can also include an
annulus access channel extending between the first port in the
tubing hanger and an annulus, the annulus being defined between the
production tubing and an innermost casing. The Christmas tree
preferably includes a radial annulus bore and a radial production
bore. Alternatively the Christmas tree includes an integral
production bore valve. In one embodiment the illustrative assembly
includes a plurality of annulus access channels arranged about the
tubing hanger and extending between the annulus and a plurality of
first ports. Preferably the plurality of annulus access channels
converge to a common eccentric connector. More preferably the
annulus access channels reduce in number between the eccentric
connector and the Christmas tree radial annulus bore. In one
particularly preferred embodiment, the plurality of annulus access
channels provides an equivalent flow area of at least 1.5 inches.
The assembly of the present illustrative embodiment can be designed
such that the crossover stab further defines the annulus access
channel. The crossover stab preferably defines the plurality of
annulus access channels.
[0105] The above described illustrative embodiment can also include
a a biasing member that is disposed between the tubing hanger and
the sliding valve. The biasing member biases the sliding valve to
the closed position. The crossover assembly further defines the
annulus access channel and preferably the crossover assembly
further defines more than one annulus access channel. In one
illustrative embodiment, the sliding valve facilitates fluid
communication between the annulus access channel defined by the
crossover assembly and the annulus access channel defined by the
crossover stab. The illustrative embodiment of the present
invention can alternatively include a Christmas tree that further
defines the annulus access channel. Preferably the crossover
assembly further includes a radial annulus bore and a radial
production bore. More preferably, the crossover assembly further
includes an orientation helix for facilitating the alignment of the
crossover radial annulus bore with the tree radial annulus bore and
the crossover radial production bore with the tree radial
production bore.
[0106] It is also contemplated that the assembly of the present
invention includes an extendable/retractable production stab, the
production stab being extendable between the tree radial production
bore and the crossover radial production bore. In one illustrative
embodiment including the extendable/retractable annulus stab, the
annulus stab is extendable between the tree radial annulus bore and
the crossover radial annulus bore. The tree and the crossover
assembly are preferably independently retrievable when the annulus
stab is retracted. In a similar manner it is contemplated that the
tree and the crossover assembly are independently retrievable when
the production stab is retracted. The production stab mechanism
includes a first shaft, a second shaft operatively connected to the
first shaft by a pair of bevel gears, and a threaded connection
between production stab and the first shaft. Preferably the
mechanism further includes an anti-rotation key to prevent the
production stab from rotating with the first shaft. The assembly of
the present invention may also include an annulus stab mechanism in
which the mechanism includes a first shaft, a second shaft
operatively connected to the first shaft by a pair of bevel gears,
and a threaded connection between annulus stab and the first shaft.
In one preferred embodiment, the mechanism further includes an
anti-rotation key to prevent the annulus stab from rotating with
the first shaft. The assembly of the present illustrative
embodiment alternatively includes a second port in the sliding
valve to selectively allow fluid communication of chemicals between
the second port in the sliding valve and a second port in the
tubing hanger. In such an illustrative assembly, the tubing hanger
includes a chemical injection channel extending between the second
port in the tubing hanger and a production tubing. A plurality of
chemical injection channels is contemplated and may be arranged
about the tubing hanger and extending between the production tubing
and a plurality of second ports. In one illustrative embodiment,
the plurality of chemical injection channels converge to a common
eccentric connector. Preferably the plurality of chemical injection
channels reduce in number between the eccentric connector and a
Christmas tree chemical channel and more preferably the plurality
of chemical injection channels provides an equivalent flow area of
at least 0.375 inches. The crossover stab, in one illustrative
embodiment, further defines the chemical injection channel and it
is preferred that it defines a plurality of chemical injection
channels. Alternatively the crossover assembly can define the
chemical injection channel and preferably the crossover assembly
defines the one or more chemical injection channels. In one
illustrative embodiment, the sliding valve facilitates fluid
communication between the chemical injection channel defined by the
crossover assembly and the chemical injection channel defined by
the crossover stab. Alternatively, the Christmas tree can further
define the chemical injection channel.
[0107] As is presently contemplated, the present invention may also
encompass a subterranean oil or gas well assembly that includes: a
wellhead; a Christmas tree coupled to the wellhead; and a single
bore tubing hanger landed within the wellhead. The tubing hanger
has a production tubing suspended from it The single bore tubing
hanger further includes a plurality of first closable ports
therein, the first closable ports facilitating fluid communication
to an annulus defined by the production tubing and an innermost
casing. The single bore tubing hanger further includes a plurality
of tubing hanger annulus access channels extending from at least
one of the plurality of first closable ports to the annulus. The
illustrative assembly optionally includes a plurality of uphole
annulus access channels in which the plurality of first closable
ports are correspondingly alignable with the uphole annulus access
channels to facilitate fluid communication between the uphole
annulus access channels and the tubing hanger annulus access
channels. The illustrative assembly can alternatively include a
crossover assembly landed within the tree, wherein the uphole
annulus access channels extend through aligned radial bores in the
crossover assembly and the Christmas tree. In one such embodiment
the uphole annulus access channels extend longitudinally through
the Christmas tree. The assembly can be embodied such that the
crossover assembly further includes a crossover stab and the
plurality of first closable ports further comprises a sliding
valve. The sliding valve is operable to open and close the first
closable ports to selectively allow fluid communication between the
tubing hanger annulus access channels and the uphole annulus access
channels. Alternatively, the plurality of uphole annulus access
channels can converge to a common eccentric connector, such that
the number of uphole annulus access channels is reduced between the
eccentric connector and the Christmas tree. The present
illustrative assembly can be made such that the single bore tubing
hanger further includes a second plurality of closable ports and a
plurality of tubing hanger chemical injection channels extending
from the second plurality of closable ports, through the tubing
hanger, and to the tubing hanger bore. The assembly may
alternatively be made to include a plurality of uphole chemical
injection channels, in which the plurality of first closable ports
are correspondingly alignable with the uphole chemical injection
channels to facilitate fluid communication between the uphole
chemical injection channels and the tubing hanger chemical
injection channels. The crossover assembly can be landed within the
tree, such that the uphole chemical injection channels extend
through aligned longitudinal bores arranged about the crossover
assembly and the Christmas tree. The crossover assembly can also
include a crossover stab and the plurality of second closable ports
further comprises a sliding valve. In such an illustrative
embodiment, the sliding valve is operable to open and close the
second closable ports to selectively allow fluid communication
between the tubing hanger chemical injection channels and the
uphole chemical injection channels. In another illustrative
embodiment of the present invention, the plurality of uphole
chemical injection channels converge to a common eccentric
connector, and wherein the number of uphole chemical injection
channels is reduced between the eccentric connector and the
Christmas tree.
[0108] The present invention also contemplates a method of
servicing a subterranean well. Such an illustrative method includes
the steps of: providing a wellhead preferably with a BOP stack
mounted onto the wellhead; installing a tubing hanger the wellhead
and installing a christmas tree with an internal crossover assembly
mounted therein onto the wellhead In one embodiment, the tubing
hanger includes: a bore concentric with the wellhead and a
plurality of channels bored longitudinally partially therethrough,
the plurality of channels being spaced around the circumference of
the tubing hanger. In another embodiment, the tubing hanger further
includes a plurality of first ports and a plurality of second ports
and a sliding valve for selectively opening and closing the first
and second pluralities of ports. In another embodiment, the
Christmas tree includes an extendable/retractable stab between
radial bores in the crossover assembly and Christmas tree. The
illustrative method may also include the step of retracting the
stab. Optionally, the method may include the step of retrieving the
Christmas tree separately from the tubing hanger. In another
illustrative embodiment the method includes the step of retrieving
the crossover assembly and the tubing hanger while the Christmas
tree remains connected to the wellhead. In yet another illustratvie
embodiment, the method may include the step of opening the sliding
valve by inserting a crossover stab to position the sliding valve
in an open position.
[0109] One of ordinary skill in the art should also appreciate that
the present invention includes a subsea wellbore production
apparatus with a side-production bore christmas tree, a production
tubing hanger, and an internal crossover assembly. It should be
appreciated that the improvement to such an apparatus includes a
production stab that is retractable into the Christmas tree and
extendable between radial bores in the christmas tree and the
crossover assembly. In such an apparatus, the stab provides a
sealed flow path between the crossover assembly and the christmas
tree. Preferably the production stab further includes an actuation
mechanism. The actuation mechanism includes: a first rotatable
shaft in threaded engagement with the production stab; and a
rotational key lock preventing rotation of the production stab;
such that rotation of the first shaft is translated into axial
movement of the production stab. The apparatus may also include a
second rotatable shaft operatively connected to the first
rotational shaft by gears, wherein rotation of the second rotatable
shaft is translated into rotation of the first rotational shaft.
The illustrative apparatus may optionally include an annulus stab
which is retractable into the Christmas tree and extendable between
second radial bores in the Christmas tree and the crossover
assembly. The apparatus preferably has a plurality of annulus
access channels spaced around the tubing hanger and the crossover
assembly, and wherein the annulus access channels communicate with
a Christmas tree annulus channel. In an alternative embodiment, the
apparatus includes a plurality of chemical injection channels
spaced around the tubing hanger and the crossover assembly, and
wherein the chemical injection channels communicate with a
christmas tree chemical injection channel.
[0110] While the present invention has been particularly shown and
described with reference to a particular illustrative and preferred
embodiments thereof, it will be understood by those skilled in the
art that various changes in form and details may be made without
departing from the scope of the invention. The above-described
embodiments are intended to be merely illustrative, and should not
be considered as limiting the scope of the present invention which
is defined in the following claims.
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