U.S. patent application number 11/760301 was filed with the patent office on 2008-12-11 for subsea intervention riser system.
Invention is credited to David Barnes.
Application Number | 20080302535 11/760301 |
Document ID | / |
Family ID | 40094789 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080302535 |
Kind Code |
A1 |
Barnes; David |
December 11, 2008 |
Subsea Intervention Riser System
Abstract
The invention comprises a multi-component system for subsea
intervention. The system comprises a lower riser component which is
held vertical by a buoyance element and an upper riser system. The
upper riser system is a continuous, enjoined conduit with
sufficient flexibility to absorb the motion of the deployment
vessel without adversely affecting the function of the intervention
system.
Inventors: |
Barnes; David; (Rio de
Janeiro, BR) |
Correspondence
Address: |
FULBRIGHT & JAWORSKI, LLP
1301 MCKINNEY, SUITE 5100
HOUSTON
TX
77010-3095
US
|
Family ID: |
40094789 |
Appl. No.: |
11/760301 |
Filed: |
June 8, 2007 |
Current U.S.
Class: |
166/339 |
Current CPC
Class: |
E21B 19/004 20130101;
E21B 17/015 20130101; E21B 17/01 20130101; E21B 41/04 20130101;
E21B 17/012 20130101 |
Class at
Publication: |
166/339 |
International
Class: |
E21B 7/12 20060101
E21B007/12 |
Claims
1. A subsea intervention system comprising: (a) a lower riser
component; (b) a first buoyancy element attached to the upper end
of said lower riser component; (c) an upper riser component
extending between the upper end of said lower riser component and a
surface vessel, said upper riser component having sufficient
flexibility to absorb the motion of said surface vessel without
adversely affecting the operation of said intervention system; (d)
a second buoyancy element attached to said upper riser system,
wherein said upper riser component comprises continuous un-jointed,
unbonded composite pipe.
2. The intervention system of claim 1 wherein said lower and upper
user components comprise multi bore risers.
3. The intervention system of claim 1 further comprising a
disconnect system between said upper and lower riser
components.
4. The intervention system of claim 1 wherein said lower riser
component is connected to a Xmas tree.
5. The intervention system of claim 4 further comprising a Blowout
Preventer placed between said lower riser component and said Xmas
tree.
6. The intervention system of claim 1 further comprising an
external conduit mounted to said upper and lower riser
components.
7. The intervention system of claim 1 wherein the upper and lower
riser components are lined.
8. The intervention system of claim 1 further comprising a pressure
activated sealing system at the bottom of the upper riser
component.
9. The intervention system of claim 1 further comprising a motion
compensation system located between the upper and lower riser
components.
10. A subsea intervention system comprising: (a) a lower riser
component; (b) an upper riser component extending between said
lower riser component and a surface vessel, said upper riser
component comprising continuous, un-jointed, unbonded composite
pipe;
11. The intervention system of claim 10 wherein the upper riser
component has sufficient flexibility to absorb the motion of said
surface vessel without adversely affecting the operation of said
intervention system.
12. The intervention system of claim 10 wherein the said upper and
lower riser components comprise two or more bores.
13. The intervention system of claim 10 further comprising a
disconnect system located between said upper and lower riser
components.
14. The intervention system of claim 10 further comprising a
disconnect system between said upper and lower riser
components.
15. The intervention system of claim 10 wherein said lower riser
component is connected to a Xmas tree.
16. The intervention system of claim 15 further comprising a
Blowout Preventer placed between said lower riser component and
said Xmas tree.
17. The intervention system of claim 10 further comprising an
external conduit mounted to said upper and lower riser
components.
18. The intervention system of claim 10 wherein the upper and lower
riser components are lined.
19. The intervention system of claim 10 further comprising a
pressure activated sealing system at the bottom of the upper riser
component.
20. The intervention system of claim 10 further comprising a motion
compensation system located between the upper and lower riser
components.
21. The intervention system of claim 10 where in the lower riser
component comprises continuous/un-jointed unbonded composite pipe.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
REFERENCE TO A COMPACT DISK APPENDIX
[0003] Not Applicable.
TECHNICAL FIELD
[0004] The invention relates to a riser system for accessing and
servicing sub-sea oil and gas wells and subsea equipment
installations. The riser system may be used to access an existing
well to carryout intervention operations or for interventions
associated with other subsea installations and equipment such as
subsea Xmas trees/well heads, manifolds, access points, pipelines,
flowlines and umbilicals. Such access is required, for example, to
take further measurements of the reservoir or to make various
maintenance, inspection, and repair operations.
[0005] The invention provides a technique to enable subsea well,
installation and flowline intervention using electric braided
wireline, slick wireline, coiled tubing and numerous intervention
tools required for such intervention. This invention allows vessels
and rigs to quickly and efficiently access subsea wells,
installations and flowlines.
BACKGROUND OF THE INVENTION
[0006] Subsea wells and fields are being developed in order to
produce hydrocarbon based fluids from subsea environments. In order
to develop such fields and wells, it is necessary to drill subsea
well and install equipment on the seabed to enable production and
fluid movement. During the production life of a subsea oil and gas
field, there is a compelling case to perform interventions in order
to maintain optimal production levels of desired fluids. Following
equipment installation, subsea wells and seabed equipment
installations periodically require maintenance, repair, inspection,
further equipment additions, modification and development making it
necessary to perform service related intervention work. In fields
where access to wells can be performed from surface, multiple
interventions are normally made to sustain optimal hydrocarbon
production. For subsea wells and in particular where water depths
become increased, the cost of performing simple or basic
interventions become extremely high and also have significant
associated potential risk.
[0007] In order to perform subsea intervention related service
work, it is necessary to overcome several technical and operational
hurdles. The industry would normally perform subsea well
intervention using a drilling rig or similar heavy intervention
vessel. Such intervention operations are very costly to mobilize
and take several days to mobilize and demobilize for intervention
operations. The industry has therefore pursued several alternate
techniques for subsea well intervention work, mainly in shallow
water depths with very special subsea intervention equipment
including open water braided electric wireline, slick wireline,
coiled tubing, lubricators, heave compensating cranes and pressure
containing equipment. Such operations are normally also supported
by remotely operated vehicles and divers.
BRIEF SUMMARY OF THE INVENTION
[0008] The dual riser system will consist of two main elements, a
lower and a surface riser systems. The lower riser system will be
connected to the well, equipment installation, pipes, other risers
or flow line at the seabed level. At the top of the lower riser
system, buoyancy will be fitted to preferably maintain the lower
riser system in tension and thus in a near vertical orientation at
some intermediate depth below the splash zone of the sea, typically
from 100 m to about 300m, and with due consideration for depth
allowance required to permit the surface riser system to absorb the
vessel motion without damaging or impeding the operation of the
intervention systems. Whilst it will be preferable to utilize a
riser tube of un-jointed flexible unbonded composite pipe which
could be positively buoyant and will preferably be complex bore,
single bore steel, titanium or other composite material riser could
also be utilized. Having positive buoyancy on the fully deployed
lower riser system will help to keep riser under tension and near
vertical. The internal bores of the riser systems will be made from
composites or extrusions and will maintain position within the
riser systems using spacers allowing interventions systems such as
coiled tubing, wireline, slickline to move efficiently inside the
riser system. The buoyancy provided on the lower riser system will
incorporate a remotely operated vehicle (ROV) operable connector
system that will allow the surface riser system to connect to the
buoy and subsequently to the lower riser system. To assist in this
task the buoy will be fitted with a ROV alignment system to ensure
efficient connection process.
[0009] The surface riser system will also comprise preferably of
riser tube fabricated from flexible unbonded continuous un-jointed
composite pipe which would be positively buoyant and will
preferably be complex bore. Single bore steel, titanium or other
composite material riser could also be utilized. The bores in the
riser system will allow for the deployment and free movement of
fluids, coiled tubing, wireline or slickline within the riser
system. The primary purpose of the surface riser system will be to
absorb vessel motion without damaging or impeding the operation of
the intervention systems. The surface riser system will be deployed
with additional over length to create a sag bend to absorb vessel
motion and thus avoid the high cost to have heave compensation
incorporated in the deployment of surface intervention hardware.
Access to the surface riser system will be vertical. The surface
riser system can be disconnected from the riser in any abandonment
situation e.g. for reasons of weather, drive off. The surface riser
system preferably will also incorporate a disconnect system which
will include sealing, disconnecting and cutting capability.
[0010] The foregoing has outlined rather broadly the features and
technical advantages of the present invention in order that the
detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention
will be described hereinafter which form the subject of the claims
of the invention. It should be appreciated by those skilled in the
art that the conception and specific embodiment disclosed may be
readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent constructions do not depart from the spirit
and scope of the invention as set forth in the appended claims. The
novel features which are believed to be characteristic of the
invention, both as to its organization and method of operation,
together with further objects and advantages will be better
understood from the following description when considered in
connection with the accompanying figures. It is to be expressly
understood, however, that each of the figures is provided for the
purpose of illustration and description only and is not intended as
a definition of the limits of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of the present invention,
reference is now made to the following descriptions taken in
conjunction with the accompanying drawing, in which:
[0012] FIG. 1 is an elevation view of a two-component riser system
of the invention connected in a typical well intervention
configuration;
[0013] FIG. 2 is a is an elevation view of a two-component riser
system of the invention with an alternate intervention system for
flow line intervention;
[0014] FIG. 3 is a is an elevation view of a two-component riser
system of the invention intervening on a flow line or other subsea
equipment installation;
[0015] FIG. 4 is a cross-section of a two-component riser
system;
[0016] FIG. 5 is a cross-section of a riser system with complex
bore;
[0017] FIG. 6 is a cross-section of a riser system with complex
bore and external conduit.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The invention allows for connection to any number of subsea
installations to include Xmas trees, wellheads, manifolds, access
points, pipelines, flow lines, umbilicals and resins to a subsea
intervention vessel, rig or other type of craft. The invention
enables subsea well, installation, pipeline and flow line invention
utilizing a variety of equipment including, but not limited to
electric braided wire line, slick electric wire line, coiled tubing
and other intervention tools. The intervention tools may be
remotely powered, subpowered or unpowered.
[0019] The riser system of the invention allows vessels and rigs to
quickly and efficiently access subsea wells, installations and flow
lines. Typical vessels that can deploy the system include open
water light weight intervention vessels, light weight construction
vessels, large construction and intervention vessels and rigs. The
light nature of un-jointed flexible unbonded composite pipe enables
the use of light weight vessels. The riser system can be deployed
from a number of locations on the vessel to include the stern, side
or through a moon pool.
[0020] Referring to FIG. 1, the riser system of the invention is
deployed from a surface vessel 101 to access a subsea wellhead by
the connection of the lower riser component 103 and the upper riser
component 104. The riser system may be deployed through a moon pool
105 located in the center of the vessel 101 or it may be deployed
from the stern or other locations on the vessel.
[0021] The lower riser component 103 is connected to the well head
using standard connection methods. As shown in FIG. 1, the lower
component 103 is connected to the wellhead 106 and includes above
through a Blow Out Preventer (BOP) 107 and a Xmas tree 108. A
coiled tubing BOP 109, a subsea lubricator 110 and an emergency
disconnect system 111 complete the connection. A pressure activated
sealing system (not shown) may also be used at the lower end of the
lower riser component.
[0022] The lower riser component 103 is connected at its upper end
to a Buoyancy element 112 which maintains tension on the lower
component 103, keeping it in a vertical orientation. The buoyance
element 112 is attached to the lower element such that it is below
the splash zone of the sea and at a sufficient distance from the
surface to permit the upper riser component 104 to absorb the
vessel motion without damaging or impeding the operation of the
system.
[0023] The lower riser component 103 may be a single or complex
bore conduit fabricated from steel, titanium or composite
materials. In one embodiment, the lower riser is fabricated from a
flexible un-jointed unbonded composite material such as that
described in U.S. Pat. No. 6,491,779, the teachings of which are
hereby incorporated by reference.
[0024] The upper riser component 104 is connected to the lower
component 103 by means of a riser disconnect package 113 and a
swivel 114. A second buoyance element 115 is connected to the upper
riser component 104 to provide buoyancy to the upper riser
component. The second buoyance element helps define the desired
curvature of the upper riser component and the desired shape to
facilitate natural heave compensation. A slip joint or motion
compensating system may also be used to compensate for the motion
of the surface vessel.
[0025] As with the lower riser component, the upper riser component
may comprise a pressure activated sealing system located at the
lower end of the upper riser component.
[0026] The upper riser component is deployed such that there is
excess length creating a sag band 116 allows the upper riser
component to absorb the motion of the vessel.
[0027] To allow the upper riser to absorb the motion of the vessel,
the upper riser component should be flexible so that the upper
component can bend but in the sag bend without adversely affecting
the function of the riser assembly. A variety of materials can be
used to fabricate the upper riser component including steel,
titanium, and composite materials. In one embodiment, the upper
riser component is constructed of an un-jointed unbonded composite
pipe such as that disclosed in U.S. Pat. No. 6,491,779, the
teachings of which are hereby incorporated by reference. The riser
is formed from a un-jointed continuous pipe.
[0028] The connection of the lower riser component 103 to the
wellhead 106 and the upper riser component are accomplished by
means of a remotely operated vehicle (ROV) 117. To facilitate the
use of a ROV, the first buoyance element 112 is fitting a ROV
alignment system to insure an efficient connection.
[0029] The upper riser component and the lower riser component may
incorporate monitoring systems such as fiber optic monitoring
systems. The monitoring systems can be integral to the riser
component or mounted externally. The monitoring systems allow the
user to monitor the riser system for shape, stress, fatigue,
pressure and temperature.
[0030] The riser system can be either a single bore or a complex
bore. By complex bore, it is meant a riser having two or more bores
within the riser system. The bores may be of different sizes and
used for different purposes such as fluid conduit, fluid return
conduit, umbilical conduit, and tool and conveyance system conduit.
The upper and lower riser components may be lined or unlined.
[0031] The riser system can remain attached to the subsea well
installation or flow line. This allows rapid return access should
suspension or disconnection be required.
[0032] The flexible nature of the unjointed riser system permits
efficient deployment of the riser system and facilitates movement
and shape adjustment enabling easy tool or assembly deployment. The
vertical nature of the lower riser component permits gravity
assistance from tool for assembly deployment.
[0033] Another embodiment of the invention is shown in FIG. 2. In
this case, the riser system is used to access a subsea flow line or
pipeline 201. In this embodiment, the lower riser component 202
engages the pipeline 201 through a subsea manifold 203 or similar
installation. Again, a BOP 204 is in place between the manifold 203
and the lower riser 202. An emergency disconnect 205 optimal
components such as a lubricator 206 and a coil tubing BOP and
stripper 207 may also be deployed between the manifold 203 and the
lower riser 202.
[0034] FIG. 3 shows an alternate embodiment where the riser system
is again attached to a flow line or pipeline. In this embodiment,
the lower riser 301 connects with a BOP 302 which in turn is
connected to a pipeline elbow 303. The elbow 303 engages a subsea
connection tool system 304 which, in turn is connected to the
pipeline 305. As with the other embodiments, an emergency
disconnect system 306 is placed between the riser 301 and the BOP.
An optimal lubricator 307 and coiled tubing BOP 308 is also
shown.
[0035] As discussed above, the bore of the riser can be a single
bore or a complex bore with the bores serving different functions.
FIG. 4 is an illustration of a single bore riser of the invention.
In this example, the riser has a simple outer layer 401 and a
second smaller layer 402.
[0036] In this example, an external conduit 403 is also provided.
The external conduit can be used in a variety of ways to include
deployment of a fiber optic monitoring system like that discussed
above.
[0037] FIG. 5 shows an example of a complex bore for an
intervention riser system. In this case, the riser has an outer
layer 501 and one inner layer 502. Within the inner layer, there
are separate conduits 502, 503 and 504. The system may also have
further conduits.
[0038] In this example, the conduits comprise a conduit fitted for
a control power or communications umbilical 503, a conduit for
coiled tubing 504 and a conduit for wire line or slick line 505. As
discussed above, a variety of different conduits can be used with
the riser. The illustrative conduits are merely exemplary and do
not emit the range of possible conduits.
[0039] FIG. 6 is a cross section of yet another embodiment of the
invention. In this embodiment, a complex bore 601 has internal
conduits 602, 603 and 604. In addition, the riser system has an
external conduit 605 fitted to the riser system.
[0040] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure of the present invention, processes, machines,
manufacture, compositions of matter, means, methods, or steps,
presently existing or later to be developed that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention. Accordingly, the
appended claims are intended to include within their scope such
processes, machines, manufacture, compositions of matter, means,
methods, or steps.
* * * * *