U.S. patent application number 10/527224 was filed with the patent office on 2005-11-03 for system and method for well workover with horizontal tree.
Invention is credited to Milberger, Lionel J..
Application Number | 20050241821 10/527224 |
Document ID | / |
Family ID | 31994052 |
Filed Date | 2005-11-03 |
United States Patent
Application |
20050241821 |
Kind Code |
A1 |
Milberger, Lionel J. |
November 3, 2005 |
System and method for well workover with horizontal tree
Abstract
A workover system for use with a subsea horizontal tree provides
an economical solution when it is not necessary to pull the
production tubing out of the well and/or when a subsea drilling BOP
is not required. The system utilizes a riser and riser adaptor. An
annulus flow line for connection to the annulus is provided with
the riser. The workover system is adaptable to multiple
configurations for connecting the lower end of the annulus flow
line to the subsea horizontal tree for communication with the
annulus. For instance, the annulus flow line may be connected to
the adapter, or may be connected between the well cap and tubing
hanger, or below the tubing hanger. An isolation sleeve may or may
not be utilized in various embodiments and may be constructed for
sealing and/or latching with different components depending on the
embodiment. One or more control valves for the annulus flow may be
provided in several different/alternative positions including
within the tubing hanger and outside of the subsea horizontal
tree.
Inventors: |
Milberger, Lionel J.;
(Wheelock, TX) |
Correspondence
Address: |
Loren G Helmreich
Browning Bushman
5718 Westheimer
Suite 1800
Houston
TX
77057
US
|
Family ID: |
31994052 |
Appl. No.: |
10/527224 |
Filed: |
March 10, 2005 |
PCT Filed: |
September 12, 2003 |
PCT NO: |
PCT/US03/28876 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60410065 |
Sep 12, 2002 |
|
|
|
Current U.S.
Class: |
166/100 |
Current CPC
Class: |
E21B 33/038 20130101;
E21B 17/01 20130101 |
Class at
Publication: |
166/100 |
International
Class: |
E21B 033/12 |
Claims
What is claimed is:
1. A workover system for a subsea horizontal tree wherein a subsea
drilling BOP is not utilized and a riser extends from the subsea
horizontal tree towards the surface, the subsea horizontal tree
comprising a tubing hanger, the tubing hanger supporting a
production tubing string in a well, the well further comprising a
casing string with an annulus defined between the casing string and
the tubing string, the workover system comprising: an adapter for
connecting the riser with the subsea horizontal tree; an annulus
line for communication with the annulus; a lower end of the annulus
line being connected to a port leading into the subsea horizontal
tree for communication with the annulus; and at least one valve
mounted between the lower end of the annulus line and the annulus
for controlling fluid flow between the annulus line and the
annulus, the at least one valve being mounted in at least one of
either a position external to the subsea horizontal tree or a
position within the tubing hanger.
2. The system as defined in claim 1, further comprising: a
receptacle mounted externally to the subsea horizontal tree for
receiving and guiding a lower end of the annulus line into fluid
communication with the port, the at least one valve being mounted
adjacent to the receptacle.
3. A system as defined in claim 1, further comprising: a tree cap,
and an insertable isolation sleeve insertable through the tree cap,
the isolation sleeve having an end for sealing engagement with the
tubing hanger.
4. The system as defined in claim 3, wherein the port is spaced
axially above the tree cap and communicates with the annulus along
a flow path adjacent to the insertable isolation sleeve through the
tree cap.
5. The system as defined in claim 1, wherein the port is defined
within the adapter.
6. The system as defined in claim 1, further comprising a tree cap,
and wherein the port is defined between the tree cap and the tubing
hanger.
7. The system as defined claim 1, wherein the port is defined below
the tubing hanger.
8. The system as defined in claim 1, further comprising a tree cap,
the tree cap and the tubing hanger being formed as separate
components axially spaced apart with respect to each other.
9. A system as defined in claim 1, further comprising: the tubing
hanger defining a tubing hanger central bore therethrough in
communication with the production tubing string, the tubing hanger
also defining a substantially straight vertical flow path which is
radially offset from the tubing hanger central bore, and the at
least one valve is positioned along the vertical flow path for
controlling fluid flow between the annulus line and the
annulus.
10. A workover system for a subsea horizontal tree wherein a subsea
drilling BOP is not utilized and a riser extends from the subsea
horizontal tree towards the surface, the subsea horizontal tree
comprising a tubing hanger, the tubing hanger supporting a
production tubing string in a well, the well further comprising a
casing string with an annulus defined between the casing string and
the tubing string, the workover system comprising: an adapter for
connecting the riser with the subsea horizontal tree; a tree cap
defining a central tree cap bore therethrough; an annulus line for
communication with the annulus; the annulus line being connected to
a port for communication with the annulus; and an insertable
isolation sleeve insertable through the tree cap central bore, the
isolation sleeve having an end thereof for sealing engagement with
the tubing hanger.
11. The system as defined in claim 10, wherein the isolation sleeve
seals with the adapter.
12. The system as defined in claim 10, wherein the isolation sleeve
does not seal with the tree cap central bore.
13. The system as defined in claim 10, wherein the isolation sleeve
seals with the tree cap central bore.
14. The system as defined in claim 10, wherein the port is defined
within the adapter.
15. The system as defined in 10, wherein the port is defined
between the tree cap and the tubing hanger.
16. The system as defined claim 10, wherein the port is defined
below the tubing hanger.
17. The system as defined claim 10, wherein the insertable
isolation sleeve insertable through the tree cap central bore is
available but is not utilized or has been removed.
18. A workover system for a subsea horizontal tree wherein a subsea
drilling BOP is not utilized and a riser extends from the subsea
horizontal tree towards the surface, the subsea horizontal tree
comprising a tubing hanger, the tubing hanger supporting a
production tubing string in a well, the well further comprising a
casing string, the casing string and production tubing defining an
annulus therebetween, the system comprising: an adapter for
connecting the riser with the subsea horizontal tree; a tree cap
defining a central tree cap bore therethrough; an annulus line for
communication with the annulus; and the annulus line being
connected to a port for communication with the annulus between the
casing string and the production tubing string, the port being
formed at a position below the tree cap.
19. The workover system of claim 18, wherein the port is defined
below the tubing hanger.
20. A system as defined in claim 18, further comprising: an
insertable isolation sleeve insertable through the tree cap, the
isolation sleeve having an end for sealing engagement with the
tubing hanger.
21. The system of claim 18, further comprising a centrally
positioned tubing hanger flow passageway, and a vertically
extending flow passageway in the tubing hanger radially spaced from
the tubing hanger flow passageway and in communication with the
annulus and the port.
22. The system as defined in claim 18, further comprising a tree
cap, the tree cap and the tubing hanger being formed as separate
components axially spaced apart with respect to each other.
23. A workover system for a subsea horizontal tree wherein a subsea
drilling BOP is not utilized, the subsea horizontal tree comprising
a tubing hanger, the tubing hanger supporting a production tubing
string in a well, the well further comprising a casing string with
an annulus defined between the casing string and the tubing string,
the workover system comprising: an annulus line for communication
with the annulus; a lower end of the annulus line being connected
to a port leading into the subsea horizontal tree for communication
with the annulus; and at least one valve mounted between the lower
end of the annulus line and the annulus for controlling fluid flow
between the annulus line and the annulus, the at least one valve
being mounted in at least one of either a position external to the
subsea horizontal tree or a position within the tubing hanger; and
a riser which extends towards the surface from the subsea
horizontal tree, the riser comprising a smaller internal diameter
than an outer diameter of the tubing hanger.
23. The system as defined in claim 22, further comprising a tree
cap, the tree cap and the tubing hanger being formed as separate
components axially spaced apart with respect to each other.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the techniques for workover
of wells and, more particularly, to a system and method for
workover of a well with a horizontal tree.
BACKGROUND OF THE INVENTION
[0002] While wells have been conventionally completed with trees
wherein the production fluid passes vertically from the well
through the tree, some more recent wells have been completed with a
horizontal tree, wherein the production fluid passes laterally
through a side port in the tree. Because the production fluid from
the well passes laterally, plugs may be installed in the bores of
both a tubing hanger and a tree cap above the side port in the
horizontal tree to provide redundant seals.
[0003] Workover operations on a horizontal tree are conventionally
performed from a floating drilling rig which connects a subsea
drilling BOP to the top of the horizontal tree, with the drilling
riser extending from the surface to the top of the BOP. When a big
bore riser and BOP stack are placed on top of the horizontal tree,
various types of workover operations may be performed, including
pulling and reinstalling a tubing string. However, due to the high
expense and time of installing the subsea drilling BOP and large
diameter riser, especially in deeper water, it is desirable to
avoid that procedure when it is possible to do so. It is frequently
necessary to perform a workover operation which does not require
pulling the tubing, thereby potentially avoiding the significant
expense of installing/removing the subsea drilling BOP and large
diameter riser.
[0004] U.S. Pat. No. 6,367,551 provides a method of workover in a
well with a horizontal tree. The techniques disclosed in this
patent have several shortcomings which have limited acceptance.
First, the shuttle valve in the tree cap may be prone to sticking
open when the riser is removed. Second, there is no technique to
test the closure of the shuttle valve while the riser is in place
because the riser connection must actually be removed before the
valve closes, thereby raising a potential significant problem if
the valve does stick and/or does not close completely, or develops
leaks, after the riser connection is removed. Third, the flow path
from the annulus line on the riser to the well annulus goes into
the horizontal tree, through the aforementioned shuttle valve, and
then bypasses the tubing hanger by going radially outwardly and
then radially inwardly through the tree housing making for a
complex annulus flow path that may be prone to problems. Further,
the tree cap must seal to both the tubing hanger and the test tree.
With this tree cap/tubing hanger arrangement, the entire tubing
hanger may need to be removed if problems occur with the tree cap,
or with seals between the tree cap and the tubing hanger, and/or
the complicated annulus flow path through the tree cap.
[0005] When it is not necessary to pull the tubing, then all that
may be required for the workover operation is a small diameter
riser, which may be referred to as a slimline OD riser, connected
to the top of the tree, with a small diameter BOP on the surface,
and to establish a communication path to both the tubing bore and
the tubing annulus below the tubing hanger. The bore in the
slimline riser needs to have a sufficient ID to pull and reinstall
the plugs in the tree cap and tubing hanger, and to provide full
bore access to the tubing in the well but does not require an ID
large enough to pull the tubing hanger. Workover operations using a
slimline OD riser are relatively economical, particularly in deep
water applications, because the subsea BOP stack and large OD riser
are not required. Using a slimline riser thus provides considerable
economy to the workover operation, such that these operations are
commonly known as "quickie" workovers.
[0006] Given the time and cost of installing a drilling BOP and
large diameter riser, especially at substantial well depths, the
inventor has determined that it would be highly desirable to
provide a system which is much more likely to require only the less
expensive workover. Those of skill in the art will appreciate the
present invention which provides solutions to the aforementioned
problems and other related problems.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide an
improved horizontal tree workover system for use when a subsea
drilling BOP is not required to be utilized.
[0008] It is yet another object of the present invention to provide
an improved well production system.
[0009] These and other objects, features, and advantages of the
present invention will become apparent from the drawings, the
descriptions given herein, and the appended claims. However, it
will be understood that any listed objects and advantages of the
invention are intended only as an aid in understanding certain
aspects of the invention, are not intended to limit the invention
in any way, and do not form a comprehensive or exclusive list of
objects, features, and advantages.
[0010] In a preferred embodiment of the present invention, a
workover system for a subsea horizontal tree is provided which does
not utilize a subsea drilling BOP. The subsea horizontal tree
comprises a tubing hanger supporting a production tubing string in
a well such as an oil and/or gas well. The well comprises a casing
string wherein an annulus or volume is provided between the casing
string and the tubing string. In one possible embodiment, the
workover system may comprise one or more elements such as, for
instance, a riser extending from the subsea horizontal tree towards
the surface and an adapter for connecting the riser with the subsea
horizontal tree. An annulus line for communication with the annulus
extends upwardly towards the surface with the riser and may be
utilized to establish circulation through the production tubing and
the annulus. A lower end of the annulus line may be connected to a
port such as a side port for communication with the annulus. One or
more valves are preferably mounted between the lower end of the
annulus line and the annulus for controlling fluid flow between the
annulus line and the annulus. In one embodiment, a control valve
may be mounted, for instance, externally to the subsea horizontal
tree. In another embodiment, a valve may be provided for annulus
control at a position within the tubing hanger. In another
embodiment, a receptacle may be mounted to the horizontal tree for
receiving and guiding a lower end of the annulus line into fluid
communication with the side port. One or more annulus control
valves may, for example, be mounted adjacent to the receptacle
external to the horizontal tree.
[0011] The system may further comprise a tree cap, and/or an
insertable isolation sleeve insertable through the tree cap. The
isolation sleeve preferably seals with the tubing hanger. In one
embodiment, the side port is spaced axially above the tree cap and
communicates with the annulus along a flow path adjacent to the
insertable isolation sleeve through the tree cap. In another
embodiment, the side port is defined within the adapter. In another
embodiment, the side port is defined between the tree cap and the
tubing hanger. Yet in another embodiment, the side port is defined
below the tubing hanger. In a presently preferred embodiment, the
tree cap and the tubing hanger are formed as separate components
axially spaced apart with respect to each other. In one embodiment,
the tubing hanger defines a tubing hanger central bore therethrough
in communication with the tubing. The tubing hanger may further
define a vertical flow path positioned radially offset from the
tubing hanger central bore. A control valve may also be positioned
along the vertical flow passageway for controlling fluid flow
between the annulus line and the annulus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 discloses one version of a horizontal tree adapted
for a workover operation using a slimline OD riser.
[0013] FIG. 2 is another embodiment of a horizontal tree adapted
for a quickie workover.
[0014] FIG. 3 is a third alternative of a horizontal tree adapted
for a quickie workover.
[0015] FIG. 4 is yet another embodiment of a horizontal tree
workover application using a slimline OD riser.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0016] The system and method of the present invention includes
various embodiments for conducting a quickie workover on a
horizontal tree. The workover operations do not involve the
installation of a subsea BOP stack, and only a slimline OD riser
and an annulus flow line in parallel with the riser are required,
along with ancillary surface equipment, to perform the workover
operation.
[0017] Referring to FIG. 1, the workover system 10 includes a
wellhead W having a conductor casing string CC extending downward
therefrom, and supporting a casing hanger CH from the wellhead,
with a casing string CS extending downward from the casing. hanger.
A production tubing string PTS passes upward through the wellhead W
and into the horizontal spool tree 12, which includes a production
valve 14 for controlling fluid flow through the side port in the
tree which is in communication with the production tubing string
PTS. Production valve 14 may be hydraulically and/or manually
controllable. A slimline OD riser 16 may be run in the well
together with an annulus line umbilical 18 external of the riser
16.
[0018] When the riser 16 is latched on top of the tree 12 using an
adapter 20, the plugs (not shown in FIG. 1--but see FIG. 2) are
pulled from both the tree cap 22 and the tubing .hanger 24. An
isolation sleeve 26 may then be run inside the riser 16 and
mechanically locked into a locking profile on the adapter 20, with
the isolation sleeve 26, at least in this embodiment, being sealed
to both the adapter 20 and the tubing hanger 24 by one or more
seals 28, 30. The bore on the isolation sleeve 26 thus provides
full bore access to the production tubing string PTS.
[0019] Annulus access is achieved utilizing the annulus line
umbilical 18 which passes through a side port 19 in the adapter 20.
In this embodiment, adaptor 20 is utilized above tree cap 22. The
flow path then extends past tree cap 22 by any suitable means such
as a flow path between isolation sleeve 26 and tree cap 22, or
other suitable flow path (not shown), through preferred
substantially vertical flow path 34, and into the annulus of the
tree surrounding the isolation sleeve 26. A ball valve 32 provided
in a vertically extending passageway 34 in the tubing hanger 24
thus provides control between the annulus surrounding the
production tubing string and the annulus line umbilical 18. Thus,
it is possible to establish circulation to circulate fluid through
the production tubing string PTS and then through the annulus. Ball
valve 32 is preferably hydraulically and/or manually operable, like
valve 14. Unlike, the prior art valve system, ball valve 32 can be
tested as desired. Latching dogs 36 or a latching ring may be used
to axially fix the isolation sleeve 26 to the adapter or other
latching means may be utilized. Conventional dogs or locking rings
may be used to secure each of the tree cap 22 and the tubing hanger
24 within the horizontal tree 12, with conventional seals between
the tree cap and the horizontal tree, and between the tubing hanger
10 and the horizontal tree. In one presently preferred embodiment,
significant complexity over the prior art is achieved because no
seal is required between the tree cap 22 and either the adapter 20,
the tubing hanger 24, or the isolation sleeve 26.
[0020] In FIGS. 2, 3, and 4, the same numerals are used to depict
similar components. In FIG. 2, the slimline OD riser 16 is also run
in with an annulus line umbilical 18 positioned alongside the
riser. The riser again is latched to the top of the tree 12 with
connector 52, which is a simplified adapter. In the system 40, the
lower end of the annulus line 18 is stabbed into a receptacle 42
positioned on or about the tree spool. One or more valves 43 are
positioned on the receptacle, exterior of the receptacle, or
between the receptacle and the tree spool 12 to control fluid flow
from the umbilical line 18 to the annulus surrounding the
production tubing string. Plugs 46, 48 are pulled from the tree cap
and the tubing hanger to allow access to the inside of the
production tubing string in the well. Annulus access is achieved by
providing a connection from the umbilical 18 to the annulus at a
position below the tubing hanger thereby bypassing the need to
circulate fluid through the preferably vertical flow path in tubing
hanger 24. Therefore, one advantage of the system 40 as shown in
FIG. 2 is that the annulus valve 32 in the tubing hanger does not
have to be operated by opening and/or closing during the quickie
workover operation. FIG. 2 shows the plugs 46, 48 still in the tree
cap and the tubing hanger, respectively. Because flow from the
annulus is already isolated by the seals of tubing hanger 24, this
embodiment does not require the use of an isolation sleeve as
shown. However, if desired, the isolation sleeve or a protection
sleeve may be utilized.
[0021] In FIG. 3, the slimline OD riser 16 is run with the annulus
line umbilical 18 alongside. The riser 16 is latched to the top of
the tree spool 12 with connector 52. The lower end of the annulus
line 18 is stabbed into receptacle 42 positioned on or about the
tree spool. In the system 50, valve 54 thus controls fluid flow
between the annulus line 18 and the annulus about the isolation
sleeve 26. The plugs are then pulled from the tree cap and the
tubing hanger, and the isolation sleeve 26 is run in through the
riser and locked into the tree cap by connector 36. The isolation
sleeve 26 may be sealed to the tree cap 22 (instead of adaptor 20
as in FIG. 1) and to the tubing hanger 24. The bore through the
isolation sleeve 26 again provides full bore access from the riser
ID to the production tubing string PTS for fluid flow or, if
desired, for running a wireline tool or a coiled tubing string into
the production tubing string, or other purposes. The annulus access
is obtained from a line 18 for connection to the region below the
tree cap 22 and above the tubing hanger 24 through port 55 in the
tree spool 12. The annulus path continues through the annulus valve
32, through the preferably vertical passageway in the tubing hanger
24 to the annulus between CS and PTS below the tubing hanger 24.
Valve 55 is preferably hydraulically or manually controllable.
[0022] In FIG. 4, the slimline OD riser is run with the annulus
line umbilical 18, and the riser 16 may be latched to the top of
the tree with adapter 20. The lower end of the annulus line is then
stabbed into a receptacle 42 on or about the tree spool below
tubing hanger 24 to provide direct access to the annulus between
the production tubing string PTS and the casing string CS. The
plugs are pulled from the tree cap and the tubing hanger, and an
isolation sleeve 26 is run inside the riser and locked into a
profile in the adapter 20 by connector 36, with the isolation
sleeve being sealed to both the adapter and the tubing hanger. The
bore in the isolation sleeve again provides full access to the
production tubing string PTS. Annulus access is achieved from the
line 18 to the tubing annulus below the production tubing hanger
24. Suitable controllable valves for annulus line 18 may be
provided, such as in the general mounting stabbing structure 42.
Note that the isolation sleeve and arrangement shown in FIG. 2
might be utilized, if desired, to avoid the need for adaptor
20.
[0023] Note that the use of separate wellhead cap 22 and tubing
hanger 24 result in redundant seals for more safely sealing off the
well. In this embodiment, no additional seals are therefore
required between wellhead cap 22 and tubing hanger 24. The
resulting structure is simpler and therefore more reliable. As
well, if desired, the well head cap 22 could be pulled without
requiring pulling out the tubing hanger 24. This arrangement also
lends itself to much more flexibility in positioning the annulus
port in the well spool, such as above both well head cap 22 and
tubing hanger 24, between well head cap 22 and tubing hanger 24, or
below tubing hanger 24. Different types of isolation sleeves 26 may
be utilized and different connections to the risers, such as
connector 20, may be utilized. The valves for controlling annulus
flow do not require a special physical connection between the
annulus valve and the connection to the riser, such as that shown
in the prior art wherein in one embodiment the weight of the
connection opens the valve. Thus, the present invention provides a
simpler, more reliable, and much more flexible system and methods
for well workovers with horizontal tree.
[0024] The foregoing disclosure and description of the invention is
illustrative and explanatory of preferred embodiments. It would be
appreciated by those skilled in the art that various changes in the
size, shape of materials, as well in the details of the illustrated
construction or combination of features discussed herein may be
made without departing from the spirit of the invention, which is
defined by the following claims.
* * * * *