U.S. patent application number 10/330453 was filed with the patent office on 2003-07-03 for casing hanger annulus monitoring system.
Invention is credited to Buckle, Kevin G., Lovell, Richard, Massie, Alfred, Moore, Harry A., Osborne, John H..
Application Number | 20030121667 10/330453 |
Document ID | / |
Family ID | 26987291 |
Filed Date | 2003-07-03 |
United States Patent
Application |
20030121667 |
Kind Code |
A1 |
Massie, Alfred ; et
al. |
July 3, 2003 |
Casing hanger annulus monitoring system
Abstract
A subsea wellhead assembly has the capabilities of communicating
from a tree assembly mounted on an inner wellhead housing to a
casing annulus. A passage in the wellhead assembly extends within
the bore of the wellhead housing from the casing annulus to the
tree assembly. A portion of the passage is located within a casing
hanger. The passage is opened and closed by a valve. The valve does
not open the passage until the tree assembly is connected to the
wellhead housing and a tubing hanger orientation sleeve lands in
the wellhead assembly. The tubing hanger orientation sleeve
actuates the valve when it lands to open the passage. When the
passage is opened, the casing annulus is in fluid communication
with the interior surface of the wellhead housing, which is in
communication with the tree assembly. The valve can be located in
the casing hanger, or in a bridging hanger
Inventors: |
Massie, Alfred; (Aberdeen,
GB) ; Moore, Harry A.; (Houston, TX) ; Lovell,
Richard; (Aberdeen, GB) ; Buckle, Kevin G.;
(Aberdeen, GB) ; Osborne, John H.; (Aberdeen,
GB) |
Correspondence
Address: |
James E. Bradley
BRACEWELL & PATTERSON , LLP
P.O. Box 61389
Houston
TX
77208-1389
US
|
Family ID: |
26987291 |
Appl. No.: |
10/330453 |
Filed: |
December 27, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60344288 |
Dec 28, 2001 |
|
|
|
Current U.S.
Class: |
166/344 ;
166/368 |
Current CPC
Class: |
E21B 33/035 20130101;
E21B 33/076 20130101 |
Class at
Publication: |
166/344 ;
166/368 |
International
Class: |
E21B 007/12 |
Claims
What is claimed is:
1. A subsea wellhead assembly comprising: a tubular wellhead member
having a bore, the wellhead member being adapted to register with a
tree assembly; a casing hanger adapted to be secured to a string of
casing defining a casing annulus, the casing hanger landing in the
bore of the wellhead member; a passage extending from the casing
annulus into the wellhead member above the casing hanger; a
normally closed valve that opens and closes the passage; and a
lower component of a tubing hanger assembly that lands in the bore
of the wellhead member and engages the valve while the lower
component is landing to move the valve from a closed position to an
open position.
2. The subsea wellhead assembly of claim 1, further comprising a
spring located within the valve that actuates the valve to close
the passage.
3. The subsea wellhead assembly of claim 2, wherein the spring
expands in order to actuate the valve to close the passage, and the
tubing hanger assembly opens the passage when the tubing hanger
assembly engages the valve by compressing the spring.
4. The subsea wellhead assembly of claim 1, further comprising a
seal extending around the casing hanger that engages the bore of
the wellhead member, the seal blocking upward communication from
the casing annulus other than through the passage.
5. The subsea wellhead assembly of claim 1, wherein the passage
extends from the casing annulus through the casing hanger to a bore
of the casing hanger.
6. The subsea wellhead assembly of claim 1, further comprising a
bridging hanger that has a lower portion landing in a bore of the
casing hanger; and wherein the passage has a lower bridging portion
extending through the lower portion of the bridging hanger and
communicating with the wellhead member above the casing hanger.
7. The subsea wellhead assembly of claim 6, wherein the passage has
a casing portion that extends from the casing annulus through the
casing hanger to the bore of the casing hanger, the casing portion
being in communication with the lower bridging portion.
8. The subsea wellhead assembly of claim 1, further comprising a
bridging hanger that lands on the casing hanger; and wherein the
valve is located in the bridging hanger.
9. The subsea wellhead assembly of claim 8, wherein the passage has
a lower bridging portion extending from the casing annulus through
the bridging hanger to the valve, and an upper bridging portion
extending from the valve through the bridging hanger into the
wellhead member above the casing hanger.
10. The subsea wellhead assembly of claim 1, wherein the passage
extends from the casing annulus through the casing hanger to a bore
of the hanger, and the valve is located within the casing
hanger.
11. A subsea wellhead assembly comprising: a tubular wellhead
member having a bore, the wellhead member being adapted to register
with a tree assembly; a casing hanger adapted to be secured to a
string of casing defining a casing annulus and having a bore, the
casing hanger landing the casing hanger landing in the bore of the
wellhead member; a passage extending from the casing annulus to the
wellhead member above the casing hanger; a valve that opens and
closes the passage; and a tubing hanger orientation sleeve that
lands in the bore of the wellhead member and cooperatively engages
the valve to move the valve to an open position.
12. The subsea wellhead assembly of claim 11, further comprising a
spring that closes the valve prior to landing the orientation
sleeve, the orientation sleeve compressing the sleeve to open the
valve while landing.
13. The subsea wellhead assembly of claim 11, wherein the passage
extends through the casing hanger, and the valve is mounted in the
casing hanger.
14. The subsea wellhead assembly of claim 11, further comprising a
bridging hanger that lands in the bore of the casing hanger, at
least a portion of the passage extending through the bridging
hanger, and the valve being mounted in the bridging handger.
15. The subsea wellhead assembly of claim 14, wherein: a portion of
the valve protrudes into a bore of the bridging hanger for
engagement by the orientation sleeve; and the bridging portion of
the passage further comprises a lower bridging portion extending
from the valve that communicates with the casing annulus and an
upper bridging portion extending from the valve that communicates
with the bore of the wellhead member, the upper and lower bridging
portions being in fluid communication when the valve is in a lower
position and not in communication when the valve is in an upper
position.
16. The subsea wellhead assembly of claim 11, wherein: the passage
extends from an exterior of the casing hanger into the bore of the
casing hanger; the valve is mounted in the casing hanger and
spring-biased to a normally closed position; and the orientation
sleeve has a lower portion that lands in the bore of the casing
hanger and contacts the valve.
17. A method for communicating with a casing annulus in a wellhead
assembly comprising the following steps: (a) providing a casing
hanger in a bore of a tubular wellhead member, a casing annulus
formed around a string of casing hanging from the casing hanger,
and a passage that is in fluid communication with the casing
annulus and the bore of the wellhead member; then (b) locating a
valve in the wellhead member and closing the passage with the
valve; then (c) cooperatively landing a lower component of a tubing
hanger assembly in the bore of the wellhead member, engaging the
valve with the lower component, and moving the valve from the
closed position to an open position.
18. The method of claim 17, wherein step (c) comprises connecting a
tubing hanger orientation sleeve to a tree assembly, and landing
the tree assembly on the wellhead member.
19. The method of claim 17, wherein step (b) comprises
spring-biasing the valve to the closed position.
20. The method of claim 17, wherein step (b) comprises: providing a
bridging hanger, the passage having at least a portion in the
bridging hanger; then locating the valve in the bridging hanger;
then landing the bringing hanger in the bore of the wellhead
member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] This invention relates in general to offshore drilling and
production equipment, and in particular to a subsea well system for
monitoring the pressure in a non-producing string of casing through
the completion system.
[0003] 2. Description of Related Art
[0004] A subsea well that is capable of producing oil or gas will
have a conductor housing secured to a string of conductor pipe
which extends some short depth into the well. A wellhead housing
lands in the conductor housing. The wellhead housing is secured to
an outer or first string of casing, which extends through the
conductor to a deeper depth into the well. Depending on the
particular conditions of the geological strata above the target
zone (typically, either an oil or gas producing zone or a fluid
injection zone), one or more additional casing strings will extend
through the outer string of casing to increasing depths in the well
until the well is cased to the final depth. Each string of casing
is supported at the upper end by a casing hanger. The casing hanger
lands in and is supported by the wellhead.
[0005] In some shallow wells and in some fluid injection wells,
only one string of casing is set within the outer casing. Where
only one string of casing is set within the outer casing, only one
casing hanger, the production casing hanger, is landed in the
wellhead housing.
[0006] The more typical case is where multiple strings of casing
are suspended within the wellhead housing to achieve the structural
support for the well to the depth of the target zone. Where
multiple strings of casing hangers are landed in the wellhead
housing, each casing hanger is above the previous one in the
wellhead housing. Between each casing hanger and the wellhead
housing, a casing hanger packoff is set to isolate each annular
space between strings of casing. The last string of casing extends
into the well to the final depth, this being the production casing.
The strings of casing between the outer casing and the production
casing are intermediate casing strings.
[0007] When drilling and running strings of casing in the well, it
is critical that the operator maintains pressure control of the
well. This is accomplished by establishing a column of fluid with
predetermined fluid density inside the well. During drilling
operations, this fluid is circulated down into the well through the
inside of the drillstring out the bottom of the drillstring and
back to the surface. This column of density-controlled fluid
balances the downhole pressure in the well. When setting casing,
the casing is run into the pressure balanced well. A blowout
preventer system is employed during drilling and running strings of
casing in the well as a further safety system to insure that the
operator maintains pressure control of the well. The blowout
preventer system is located above the wellhead housing by running
it on drilling riser to the wellhead housing.
[0008] When each string of casing hanger is suspended in the
wellhead housing, a cement slurry is flowed through the inside of
the casing, out of the bottom of the casing, and back up the
outside of the casing to a predetermined point. An open fluid
communication passage in the casing hanger leading from the casing
annulus to the casing interior would adversely affect the flow path
of the cement slurry. This could also cause well pressure control
problems for the operator under certain conditions.
[0009] In a subsea well capable of producing oil or gas, the
production fluids flow through perforations made in the production
casing at the producing zone. A string of tubing extends to the
producing zone within the production casing to provide a pressure
controlled conduit through which the well fluids are produced. At
some point above the producing zone, a packer seals the space
between the production casing and the tubing to ensure that the
well fluids flow through the tubing to the surface. The tubing is
supported by a tubing hanger assembly that lands and locks above
the production casing hanger, either in the wellhead housing, in a
tubing hanger spool, or in a horizontal or spool tree, as described
below.
[0010] Subsea wells capable of producing oil or gas can be
completed with various arrangements of the production control
valves in an assembly generally known as a tree. For wells
completed with a conventional tree, the tubing hanger assembly
lands in the wellhead housing above the production casing hanger.
Alternatively, the tubing hanger assembly lands in a tubing hanger
spool that is itself landed and locked to the wellhead housing. For
wells completed with a horizontal or spool tree, the horizontal
tree lands and seals on the wellhead housing. A tubing hanger
assembly lands and seals in the horizontal tree. The tubing hanger
assembly in conventional trees has a flow passage for communication
with the annulus surrounding the tubing. A tubing annulus bypass
extends around the tubing hanger in horizontal trees. These
passages allow for communication between the interior of the
production casing and the interior of the tubing. Virtually all
producing wells are capable of monitoring pressure in the annulus
flow passage between the interior of the production casing and the
interior of the tubing.
[0011] A sealed annulus locates between the production casing and
the next larger string of casing. Normally there should be no
pressure in the annulus between the production casing and the next
larger string of casing because the annular space between the
production casing and the next larger string of casing is
ordinarily cemented at its lower end and sealed with a packoff at
the production casing hanger end. If pressure within this annulus
increases, it would indicate that a leak exists in one of the
strings of casing. The leak could be from several places.
Regardless of where the leak is coming from, pressure build up in
the annulus between the production casing and the next larger
string of casing could collapse a portion of the production casing,
compromising the structural and pressure integrity of the well. For
this reason, operators monitor the pressure in the annulus between
the production casing and the next larger string of casing in
land-based or above water wells. Monitoring production casing
annulus pressure in a subsea well is more difficult because of lack
of access to the wellhead housing below the production casing
hanger packoff. Patents exist that show different methods for
monitoring the annulus pressure between the production casing and
the next larger casing in subsea wells.
SUMMARY OF THE INVENTION
[0012] In a subsea well assembly a tubular wellhead member or
wellhead housing having a bore registers with a tree assembly. A
casing hanger that has a bore lands in the bore of the wellhead
member. The casing hanger is adapted to be secured to a string of
casing, which defines a casing annulus. A passage extends from the
casing annulus into the wellhead member above the casing hanger.
There is also a valve in the well assembly that selectively opens
and closes the passage. The well assembly also includes a tubing
hanger assembly that lands in the bore of the wellhead member. The
tubing assembly is adapted to be connected to a string of tubing.
The tubing hanger assembly has a portion that engages the valve
while landing to move the valve from a closed position to an open
position
[0013] In the first embodiment, a portion of the passage extends
through a production casing hanger from the exterior of the
production casing hanger below the casing hanger packoff to an
outlet in the interior of the production casing hanger. A port
closure sleeve threads to the interior of the production casing
hanger. The port closure sleeve seals on both sides of the passage
outlet in the interior of the production casing hanger. With the
port closure sleeve as described, the passage between the exterior
of the production casing hanger and the bore of the production
casing is isolated. The port closure sleeve is removed before the
tree assembly is installed. After the removal, a ported production
bridging hanger lands on top of and in the casing hanger. The
ported production bridging hanger mates and seals on its exterior
surface with the interior of the production casing hanger at a
point above and below the passage outlet in the interior of the
production casing hanger. Another portion of the passage extends
through the bridging hanger, between a pair of seals, to an inlet
of the valve for opening and closing the passage.
[0014] The valve is reciprocally mounted in the bridging hanger and
is in a closed position until a tubing hanger assembly is
installed. When the tubing hanger assembly is installed, the base
of the tubing hanger assembly presses against the valve. When the
tubing hanger assembly is in its final position, the springs in the
valve are compressed, thereby opening the passage running through
the bridging hanger. The annulus pressure then communicates through
the passage to the exterior of the tree assembly. A communication
line extends from the tree to monitoring equipment at the surface
for monitoring the pressure in the annulus of the production casing
as described.
[0015] In the second embodiment, the passage includes a valve
passage, a slot, and a port that are located in the casing hanger.
The valve passage leads from the interior edge of the production
casing hanger flowby slot, which in turn opens into the production
casing annulus. The valve passage leads upward into the bore of the
casing hanger. A spring-loaded valve is reciprocally carried in the
valve passage. The valve protrudes into the casing hanger bore
while in a closed position. The casing annulus does not communicate
to the port until the tubing hanger assembly is installed because
the valve remains in a closed position until the tubing hanger
assembly is installed.
[0016] When the tubing hanger assembly is installed, the tubing
hanger assembly comes into contact and presses against the valve.
When the tubing hanger assembly has been installed, the valve moves
downward opening the valve passage. From the port, the annulus
pressure communicates to the tree assembly for monitoring the
pressure in the annulus of the production as described.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is an overall sectional view of an upper portion of a
wellhead assembly in accordance with this invention and shown with
a production casing hanger installed, but before a tree assembly
had been attached.
[0018] FIG. 2 is an overall sectional view of the wellhead assembly
of FIG. 1, after the port closure sleeve has been removed and a
ported production bridging hanger has been installed, but before a
tubing hanger assembly has been installed.
[0019] FIG. 3 is an overall sectional view of the wellhead assembly
of FIG. 1, after the tubing hanger assembly has been installed.
[0020] FIG. 4 is a sectional view of the wellhead assembly of a
second embodiment of the invention, after a tubing hanger assembly
has been installed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring to FIG. 1, one configuration for the subsea
wellhead assembly includes a conductor housing 11, which will
locate at the sea floor. Conductor housing 11 is a large tubular
member that is secured to a string of conductor pipe (not shown).
Conductor pipe (not shown) extends to a first depth into the well.
A tubular wellhead member or wellhead housing 13 lands in the
conductor housing 11. Wellhead housing 13 is typically a high
pressure tubular member having an exterior surface 15 and an
interior surface 17. Wellhead housing 13 secures to a first string
of casing, which extends through the conductor pipe (not shown) to
a deeper depth into the well. Normally, the first string of casing
(not shown) is cemented in place.
[0022] Typically, an intermediate casing hanger 19 and intermediate
casing (not shown) are installed in wellhead housing 13 in the
first string of casing. Intermediate casing hanger 19 lands on a
lower shoulder located on interior surface 17 of the wellhead
housing 13. In the preferred embodiment, an intermediate casing
hanger packoff 23 seals intermediate casing hanger 19 with interior
surface 17 of the wellhead housing 13. Intermediate casing hanger
19 secures to a string of intermediate casing (not shown), which is
cemented in place. Intermediate casing (not shown) extends between
the first string of casing (not shown) and production casing 29 to
an intermediate depth.
[0023] In the preferred embodiment, a production casing hanger or
casing hanger 21 having an interior surface and an exterior surface
lands on a shoulder on intermediate casing hanger 19. A production
casing hanger packoff 27 seals casing hanger 21 with interior
surface 17 of wellhead housing 13. A production casing 29 attaches
to a lower portion of casing hanger 21. Production casing 29
extends through the intermediate string of casing (not shown) to a
final depth of the well. Production casing 29 is cemented in
place.
[0024] A production casing annulus or casing annulus 31 is in the
space surrounding the production casing 29. In the preferred
embodiment, casing annulus 31 surrounds casing hanger 21, and
packoff 27 prevents leakage past casing hanger 21. Normally, there
would be only nominal, atmospheric pressure in casing annulus 31.
Preferably, only a lower portion of production casing 29 is exposed
to well pressure, which is through perforations (not shown). Cement
in production annulus 31 blocks communication of formation pressure
from the perforations. In the preferred embodiment, a packer (not
shown) locates in production casing 29 above these perforations to
seal the well pressure within the lower portion of production
casing 29. In the preferred embodiment, pressure other than
atmospheric is in casing annulus 31 only when a leak occurs.
[0025] Casing annulus pressure communicates through a passage. In
the preferred embodiment, there is a casing portion of the passage,
which includes a communication passage or port 33 that extends
laterally through a side of casing hanger 21 from its exterior
surface to its interior surface. In the preferred embodiment, port
33 is located at an axial position between packoffs 23 and 27. Port
33 intersects a flowby for cement return passage or slot 25 in
casing hanger 21. Typically, slot 25 extends from casing annulus 31
to the exterior surface of casing hanger 21 between packoffs 23 and
27. Packoffs 23 and 27 block communication of casing annulus
pressure both up and down interior surface 17 of wellhead housing
13 adjacent slot 25. Port 33 allows fluid communication between the
casing annulus 31 and the interior surface of casing hanger 21.
[0026] While pumping cement down the casing, cement returns through
flowby slots 25 and does not enter the bore of casing hanger 21.
Fluid communication between the interior surface and the exterior
surface of casing hanger 21 is not desired when production casing
29 is being installed. In the preferred embodiment, a port closure
sleeve 35 with upper and lower seals 37 seal port 33. Seals 37
extend around closure sleeve 35 and locate above and below port 33.
In the preferred embodiment, port closure sleeve 35 is threadedly
connected to casing hanger 21 before casing hanger 21 is run. Port
closure sleeve 35 has an interior surface and an exterior surface.
A slot 39 in the interior surface of port closure sleeve 35 allows
a tool (not shown) to be lowered from the surface to unscrew the
port closure sleeve 35 from the casing hanger 21 and remove the
port closure sleeve 35 prior to installing a tree assembly (not
shown), prior to running tubing.
[0027] Referring to FIG. 2, a ported production bridging hanger or
bridging hanger 41 is lowered into the well after the port closure
sleeve 35 has been removed, until the base of the bridging hanger
41 lands on casing hanger 21. In the preferred embodiment, there is
a bridging portion of the passage, which includes a lower bridging
passage 43 and an upper bridging passage 59. In the preferred
embodiment, lower bridging passage 43 communicates with port 33 and
extends from an exterior surface of bridging hanger 41 that is
engaging the interior surface of casing hanger 21 to a valve 51
positioned in bridging hanger 41. In the preferred embodiment,
upper bridging passage 59 extends from valve 51 to a surface of
bridging hanger 41 that is in fluid communication with interior
surface 17 of wellhead housing 13. Typically, an interior surface
of bridging hanger is the surface of bridging hanger 41 that is in
fluid communication with interior surface 17 of wellhead housing
13. Lower and upper bridging passages 43, 59 are in fluid
communication when valve 51 is in an open position, and valve 51
blocks communication when in a closed position. Preferrably, port
33 aligns with the entrance to lower bridging passage 43 when
bridging hanger 41 is installed. The inlet to passage 43 may extend
completely around bridging hanger 41 to avoid having to orient
bridging hanger 41. A set of seals 53 sealingly engages the
interior surface of production casing hanger 21 and the exterior
surface of bridging hanger 41 above and below port 33. The casing
annulus pressure communicates from port 33 into the lower bridging
passage 43.
[0028] The annulus pressure communicates vertically through the
lower bridging passage 43 to an inlet 49 of a bridging hanger valve
51. A set of seals 64 located on valve 51 engage bridging hanger
41. As shown in FIG. 2, valve inlet 49 is closed and seals 53 above
and below port 33 prevent upward communication of casing annulus
pressure 31 when valve 51 is in its closed position. As shown in
FIG. 3, the annulus pressure communicates through inlet 49 and
proceeds out a valve outlet 57 into the upper bridging passage 59
when valve 51 is in its open position.
[0029] Valve 51 includes a cylindrical rod 63 that is reciprocally
and sealingly carried in a bore that extends axially downward from
the top of bridging hanger 41. Valve 51 includes a valve spring 61
that is preferably located in the bore that valve 51 is positioned
within, and which applies a force on cylindrical rod 63. The upper
end of rod 63 extends above the interior surface of bridging hanger
41 while in the closed position. Seals 64 located around rod 63
block flow between lower and upper bridging passages 43, 59 while
valve 51 is in its upper position. Valve 51 is in its closed
position in FIG. 2 because valve spring 61 pushes valve 51 to the
closed position until enough force is applied to the top of valve
rod 63 to open valve 51 by compressing valve spring 61. When this
occurs, rod 63 moves downward, positioning seals 64 below the
junction between the communication passages 43 and 59.
[0030] Referring to FIG. 3, valve 51 is in the open position. Valve
51 opens when a tubing hanger orientation sleeve 55 is lowered into
wellhead 13, which compresses valve spring 61 until orientation
sleeve 55 lands on the top of bridging hanger 41. Tubing hanger
orientation sleeve 55 is considered herein to be a lower component
of a tubing hanger assembly that also includes, but is not limited
to, a tubing hanger 70 (lower portion shown) and a string of tubing
72. Tubing hanger orientation sleeve 55 is secured to the lower end
of a tree 71 (lower connection portion shown). Tubing hanger
orientation sleeve 55 has an interior helical cam (not shown) and
slot (not shown) that mates with a tubing hanger alignment pin
assembly 74 for aligning tubing hanger 70 with tree 71. Tubing
hanger 70 lands, locks, and seals in tree 71. Tubing hanger 70
rotates to proper orientation by the interaction of pin assembly 74
and the slot on orientation sleeve 55 as tubing hanger 70
lands.
[0031] With valve 51 in the open position, casing annulus 31
communicates through valve 51 and into upper bridging passage 59.
In the preferred embodiment, upper bridging passage 59 extends
above valve 51 substantially vertically through bridging hanger 41
and opens into a space between the interior of the bridging hanger
41 and the exterior of the tubing hanger orientation sleeve 55.
Seals 65 are located between interior of the bridging hanger 41 and
the exterior of the tubing hanger orientation sleeve 55. In the
preferred embodiment, there is a tubing hanger portion of the
passage, which includes a tubing hanger passage 67 that extends
through tubing hanger orientation sleeve 55. In the preferred
embodiment, tubing hanger passage 67 extends from an exterior
surface on its lower portion to the exterior surface on its upper
portion that is in communication with interior surface 17 of
wellhead housing 13. Seals 65 force casing annulus 31 to
communicate with tubing hanger passage 67. In the preferred
embodiment, tubing hanger passage 67 runs substantially vertically
through the tubing hanger orientation sleeve 55 and then turns
toward and opens up at the exterior surface of tubing hanger
orientation sleeve 55. In the preferred embodiment, a communication
line 69 connects to the exterior of tubing hanger orientation
sleeve 55 and is in communication with passage 67. Communication
line 69 proceeds through tree assembly 71 for monitoring in a
manner known by those with skill in the art.
[0032] In operation, the well will be drilled and cased as shown in
FIG. 1. Port closure sleeve 35 blocks casing annulus port 33 during
these operations. A riser and BOP (not shown) connect to the
wellhead housing 13 during these operations. Then a retrieval tool
(not shown) is lowered through the BOP and the riser to latch into
port closure sleeve 35 and remove it, as shown in FIG. 2. The
operator then runs the bridging hanger 41 through the BOP and
riser, and lands the bridging hanger 41 as shown in FIG. 2. Valve
51 will be in the closed position. The operator then removes the
riser and BOP from wellhead 13 and lowers the tree. The tubing
hanger orientation sleeve 55 will be attached to the lower end of
tree 71 as it is being run. Tree 71 lands on and connects to the
wellhead housing 13. At the same time, the tubing hanger
orientation sleeve 55 depresses valve 51, thereby opening
communication passages 43, 59. Any pressure that might exist in
casing annulus 31 is controlled through valves in tree 71 and the
tree running string. Production tubing 72 is then run through the
riser and tree 71, with tubing hanger 70 landing in tree 71. Pin
assembly 74 engages orientation sleeve 55 to rotate tubing hanger
70 to a position with its production outlet aligned with the
production outlet of tree 71.
[0033] In the second embodiment, as shown in FIG. 4, a production
casing hanger 73 lands on an intermediate casing hanger 75 within a
tubular wellhead member or wellhead housing 77. In this embodiment,
the casing hanger portion of the passage includes a valve passage
79, a flowby slot 81, and a port 89. Valve passage 79 is located in
casing hanger 73 and preferably extends diagonally downward from
the interior of casing hanger 73 to an upper portion of flowby slot
81. Flowby slot 81 extends through casing hanger 73 with a lower
portion that opens into a casing annulus 83. The production casing
annulus pressure communicates from the casing annulus 83, through
slot 81, and into the valve passage 79.
[0034] A valve 85 is reciprocally mounted in the annulus valve
passage 79. Valve 85 comprises a rod 86 having seals 87 that
sealingly engage the surface of valve passage 79 and a spring 88
that urges rod 86 upward. While in a closed position (not shown in
FIG. 4), rod 86 extends into the interior of the production casing
hanger 73. Valve 85 is closed because seals 87 on the exterior of
the base of the valve 85 are in contact with the walls of the
annulus valve passage 79. Port 89 extends from annulus valve
passage 79 to the interior surface of casing hanger 73. In the
preferred embodiment, port 89 extends from the interior of annulus
valve passage 79 for a short distance, then turns and extends
substantially alongside annulus valve passage 79, and opens into an
annular space 91 around a tubing hanger orientation sleeve 93.
Annular space 91 is in fluid communication with the interior
surface of wellhead housing 77. When orientation sleeve 93 lands in
the bore of casing hanger 73, orientation sleeve 93 moves valve 85
to the open position.
[0035] Port 89 connects to valve passage 79 farther away from slot
81 than the surface of valve passage that seals 87 engage when in
the closed position. Therefore, when valve 85 is closed, the
production casing annulus pressure does not communicate beyond
seals 87. But when valve 85 is open, as shown in FIG. 4, the
production casing annulus pressure communicates through flowby slot
81, into annulus valve passage 79, around seals 87, through port
89, and into annular space 91 that is in fluid communication with
the interior surface of wellhead housing 77. The tree in this
embodiment has monitors the casing annulus pressure from the
interior surface of wellhead housing 77.
[0036] In operation of the second embodiment, production casing
hanger 73 is installed onto intermediate casing hanger 75 inside of
wellhead housing 77. As installed, valve 85 is in a closed
position, blocking communication from casing annulus 31. Unlike the
first embodiment where port closure sleeve 35 (FIG. 1) must be
removed, valve 85 is automatically opened when the exterior of
tubing hanger orientation sleeve 93 is installed and pushes down
against valve 85, so that seals 87 are no longer in contact with
the interior surface valve passage 79. Orientation sleeve 93 is
installed as in the first embodiment, by attaching it to the lower
end of the tree and landing the tree on the wellhead housing 77. An
advantage of the second embodiment is that there is no need to
retrieve a closure sleeve and install a bridging hanger before
running the tree because valve 85 in the production casing hanger
73 is opened automatically by the tubing hanger orientation sleeve
93 pushing open valve 85 during installation. An advantage of the
first embodiment is the protection provided to the casing hanger
bore by closure sleeve 35 prior to removing it.
[0037] In both embodiments, the casing annulus is at all times
under safety control. In the first embodiment, when closure sleeve
35 (FIG. 1) is removed and prior to landing ported bridging hanger
41 (FIG. 2), the casing annulus monitoring passage is open.
However, the BOP and riser will be in place during this time for
safety, since bridging hanger 41 is run through the BOP and riser
prior to running the tree. In the second embodiment, the casing
annulus monitoring passage opens only when the tree and orientation
sleeve lands.
[0038] Further modifications and alternative embodiments of various
aspects of the invention will be apparent to those skilled in the
art in view of this description. Accordingly, this description is
to be construed as illustrative only and is for the purpose of
teaching those skilled in the art the general manner of carrying
out the invention. It is to be understood that the forms of the
invention shown and described herein are to be taken as the
presently preferred embodiments. Elements and materials may be
substituted for those illustrated and described herein, parts and
processes may be reversed, and certain features of the invention
may be utilized independently, all as would be apparent to one
skilled in the art after having the benefit of this description of
the invention. Changes may be made in the elements described herein
or in the steps or in the sequence of steps of the methods
described herein without departing from the spirit and the scope of
the invention as described. For example, although both embodiments
disclose a tubing hanger that lands in a production tree, the
invention would also work with tubing hangers that land in the
wellhead housing on in a tubing spool above the wellhead
housing.
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