U.S. patent application number 12/864585 was filed with the patent office on 2010-12-09 for device and method for isolating a section of a wellbore.
Invention is credited to Bard Martin Tinnen.
Application Number | 20100307774 12/864585 |
Document ID | / |
Family ID | 40637050 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100307774 |
Kind Code |
A1 |
Tinnen; Bard Martin |
December 9, 2010 |
DEVICE AND METHOD FOR ISOLATING A SECTION OF A WELLBORE
Abstract
The present disclosure relates to a device and a method for
isolating a section of a wellbore, the device including a straddle
packer (1) and associated systems (100, 10) for selectively setting
of at least one upper packer element (2), at least one lower packer
element (3) and at least one anchoring device (4) of the straddle
packer (1), wherein at least one setting element (10) of the
straddle packer (1) is operated independent from other setting
elements (100).
Inventors: |
Tinnen; Bard Martin;
(Stavanger, NO) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Family ID: |
40637050 |
Appl. No.: |
12/864585 |
Filed: |
January 22, 2009 |
PCT Filed: |
January 22, 2009 |
PCT NO: |
PCT/NO2009/000026 |
371 Date: |
August 20, 2010 |
Current U.S.
Class: |
166/387 ;
166/127 |
Current CPC
Class: |
E21B 33/1243 20130101;
E21B 23/06 20130101; E21B 33/124 20130101 |
Class at
Publication: |
166/387 ;
166/127 |
International
Class: |
E21B 33/12 20060101
E21B033/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 24, 2008 |
NO |
20080453 |
Claims
1. A device for isolating a section of a wellbore, the device
including a straddle packer and a setting tool for selectively
setting of at least one upper packer element, at least one lower
packer element and at least one anchoring device of the straddle
packer, wherein the setting tool includes at least one setting
element arranged for setting the at least one lower packer element,
wherein the at least one lower packer element is operated
independent from other setting elements by wireless communication
means comprising a transmitter located in the setting tool (100)
and a receiver located in the setting element.
2. The device according to claim 1, wherein the transmitter and the
receiver includes a transceiver.
3. The device according to claim 1, wherein the axial length L1 of
the setting tool is less than the axial length L2 of the straddle
packer.
4. The device according to claim 1, wherein the axial length of the
setting tool is less than three quarter of the axial length of the
straddle packer.
5. The device according to claim 1, wherein the axial length of the
setting tool is less than one half of the axial length of the
straddle packer.
6. The device according to claim 1, wherein the axial length of the
setting tool is less than one quarter of the axial length of the
straddle packer.
7. The device according to claim 1, wherein at least one separate
setting element is integrated in a portion of a tubular body of the
straddle packer.
8. A method for isolating a section of a wellbore, the method
including setting a straddle packer using a setting tool for
selectively setting of at least one upper packer element, at least
one lower packer element and at least one anchoring device of the
straddle packer, wherein the method comprising operating the at
least one lower packer element independent from other setting
elements by means of a setting element that is controlled by a
wireless communication means comprising a transmitter located in
the setting tool and a receiver located in the setting element.
9. The method according to claim 8, wherein the setting tool has an
axial length that is considerably less than the axial length of the
straddle packer.
Description
[0001] This invention regards a device and a method for
installation, setting and/or operation of a tool string in a well.
In particular, the present invention regards a device and a method
for isolating a section of a wellbore, the device including a
straddle packer and associated systems for selectively setting of
at least one upper packer element, at least one lower packer
element and at least one anchoring device of the straddle
packer.
BACKGROUND
[0002] Straddle packers are commonly used for zone isolation in
wells related to the production of hydrocarbons. Typically,
straddle packers are utilised to shut off unwanted production, such
as water or in some cases gas, that origins from reservoir zones in
an upper or middle section of the wells producing interval, so that
fluids, such as oil, from lower lying intervals still can be
produced. Straddle packers as long as 50-100 meters and more have
in some cases been required to shut off unwanted production.
[0003] Publication U.S. Pat. No. 6,883,610 discloses straddle
packer systems and methods of using them for downhole isolation of
zones for fracturing treatment, the system including upper and
lower seal systems having resiliently flexible sealing elements
hydraulically and operatively connected to one another which are
responsive to an increase in hydraulic pressure for setting the
sealing elements at a first hydraulic pressure threshold.
[0004] Prior art subsea well service operations (Riserless Well
Intervention--RLWI) applies tailor made well service vessels and
equipment, such as subsea lubricators, in order to service subsea
wells in an increasingly more cost effective manner. However, due
to a lack of proper technology, such methods for subsea well
service still suffer from distinctive restrictions related to types
of operations that can be performed. In particular, this applies
for operations involving long and bulky well intervention tool
strings. As a consequence, the task of getting long straddle
packers into a subsea well by means of a RLWI operation is a major
challenge.
[0005] Norwegian patent application NO 20051257, owned by the
applicant of the present application, discloses a method for
intervening subsea wells with very long toolstrings in conjunction
with RLWI operations, and is included herein by reference.
[0006] In relation to the invention according to the present
application, the invention disclosed in NO 20051257 would in some
cases of straddle packer installation be insufficient due to the
following:
[0007] In general, regarding straddle packers, it is for the very
most desirable to have a large outer diameter (OD). [0008] This may
relate to production issues; [0009] It is desirable to have as big
an inner diameter (ID) of the straddle packer as possible in order
to avoid choking of the production fluids that are going to be
produced through the straddle packer subsequent to installation. To
obtain a big ID, the OD must be accordingly large. [0010] It may
relate to requirements for subsequent operations/service; [0011] If
the inner diameter (ID) of the straddle packer becomes too small,
subsequent intervention could become problematic, as tools with a
certain size and shape might not be able to be intervened through
the straddle packer. [0012] It may be related to technical issues
with respect to the actual performance of the straddle packer after
installation; [0013] If the OD of the straddle packer can be made
sufficiently large, this entails that the required radial expansion
of the packer elements (to form a seal towards the wellbore) will
be reduced compared to a smaller OD straddle packer. This is
beneficial for many reasons. First, the pressure rating will be
higher for these "low expansion" packers as little "free packer
element" is exposed in the annulus between the straddle packer
metal body and the inner diameter of the wellbore
(tubing/liner/casing) that the straddle packer is installed in.
Secondly, low expansion systems are less expensive and more
reliable than high expansion systems. Finally, high expansion
systems entail a smaller ID of the straddle packer, as increased
wall thickness is required to provide required radial metallic
support for the high expansion packer element and/or anchors.
[0014] As a conclusion of the above bullet point list, large OD
straddle packers are generally preferred over smaller OD, high
expansion straddle packer systems.
[0015] One main challenge with the above seen in relation to
application NO 20051257 is that the requirements for a straddle
packer with a large outer diameter could conflict with the
requirements for a "flush pipe" of the application NO 20051257. As
the flush pipe would have to be made with an OD smaller than the ID
of the tubing in the well below the wellhead, the ID of the
flushpipe would be accordingly smaller than the ID of the tubing.
Hence, should a flush pipe be utilised for deploying a long
straddle packer into a subsea well, this could entail requirements
to the packer elements being of a small OD, high-expansion type,
which is undesirable according to the argumentation above.
[0016] In order to overcome this specific challenge, it is
described in application NO 20051257 that the outer body of the
straddle packer itself could fulfil the same function as the flush
pipe when lubricating the tool string into the well. This would
solve one problem, but raise another: [0017] It is known to those
skilled in the art that a straddle packer is normally set by means
of a setting tool, of similar length as the straddle packer itself.
[0018] A setting tool commonly includes a top section (including
the power module), a central, tube shaped steel rod running all the
way from the setting tool to a point under the lowermost packer
element of the straddle, and a collapsible mandrel in the bottom.
[0019] Often, such setting tools have a resulting bulky, uneven
shape that can not be deployed out through a dynamic seal without a
flush tube (ref application NO 20051257). [0020] Hence, the issue
of bringing a traditional setting tool out of the well after
setting a straddle packer could represent a major challenge in
relation to the invention of application NO 20051257, and the main
reason is that without any flush pipe according to the general idea
of the application NO 20051257, it would be impossible to lubricate
an unevenly shaped tool (i.e. the setting tool in this case) out of
the well.
[0021] Thus, it is an object of the present invention to provide an
arrangement and a method for deploying, operating and/or installing
a range of "challenging" objects, such as long objects with large
outer diameter, such as a straddle packer, in a subsea well.
[0022] Further, it is an object of the present invention to provide
an arrangement and a method for deploying, operating and/or
installing a range of "challenging" objects, such as long objects
with large outer diameter, such as a straddle packer, in wells in
general.
[0023] Publication U.S. Pat. No. 6,257,338 B1 discloses a device
for isolating a section section of a wellbore, the device including
as a straddle packer and a setting tool for selectively setting of
at least one upper packer element and at least one lower packer
element, wherein the setting tool includes at least one setting
element for setting the at least one lower packer element.
Existing Methods
[0024] In cases where the rig-up height above the wellhead is
sufficient, as would be the case on some platforms, land wells and
offshore drilling rig operations involving a riser, the entire
straddle packer with setting tool could be assembled, intervened
and installed in one run. Based on the relevant technique applied
for assembling the straddle packer and the setting tool, assembly
operations may become awkward due to a need for assembling sections
of a setting tool centre rod inside equivalent sections of the
straddle packer body (i.e. assembling of threaded rod inside
threaded pipe). Hence, the risk of loosing components into the well
during rigging as well as the time required to assemble the
straddle packer can become significant.
[0025] Further, it is known that longitudinal expansion of the
centre rod during operation of the setting tool might impair the
setting operation itself. Hence, longitudinal expansion of the
centre rod (due to the setting force applied by the setting tool
power chamber) may come in conflict with the requirement for the
setting tool to provide a certain distance of compression/stroke of
the straddle packer in order to set this. In summary, there are
numerous reasons why straddle packer setting tools of present,
comprising a long centre rod, may impose negative aspects to the
straddle packer setting operation.
[0026] In other cases, comprising wells where there are limitations
in how long lengths of tool that can be intervened in one run,
existing means for bringing long straddle packers into the well
involve splitting the relevant straddle packer into numerous
sections and installing each section in a run of its own, splicing
them together downhole by means of so-called stinger subs. In
particular, such methods would apply for subsea well servicing
(RLWI operations) where lubricator space is limited. Such
operations often become very time consuming and expensive.
[0027] For a subsea well operation, splitting a straddle packer
into separate parts would entail numerous runs in the hole to
install the straddle packer. This means additional time and cost
related to the operation. Costs for this sort of operation could
easily become substantial, possibly to the extent that such
operation is deemed non-economical. Hence, important remedial work
in the wells may be omitted due to the said cost
considerations.
[0028] Thus, there is a need for improved setting tool designs for
straddle packers and other similar well servicing tools that make
them shorter and easier to assemble and operate.
[0029] In the light of this, the potential for economic savings
represented by the invention is significant.
THE OBJECT OF THE INVENTION
[0030] The object of the invention is to provide a novel and
alternative system and method for installing and operating long and
bulky well servicing tools such as straddle packers in subsea wells
as well as other relevant well cases.
[0031] One main feature of the invention, related to straddle
packers, is the removal of the need for a setting tool of similar
length as the straddle packer. The proposed way to achieve this is
to provide for an autonomous setting of one or multiple components,
such as the lower packer element and anchor. In a preferred
embodiment, such autonomous setting is operator controlled by means
of a wireless signal sent to activate the actual components at the
determined time for installation.
[0032] Despite this text mainly describes inventive features that
mostly relates to straddle packers, it is obvious to a person
skilled in the art that a similar system and method philosophy
could be applied for other cases where autonomous
equipment/component control and operation in a wellbore would
provide improvements.
THE INVENTION
[0033] In a first aspect the present invention regards a device for
isolating a section of a wellbore, the device including a straddle
packer and associated systems for selectively setting of at least
one upper packer element, at least one lower packer element and at
least one anchoring device of the straddle packer, the at least one
setting element of the straddle packer is operated independent from
other setting elements.
[0034] As mentioned, common, known prior art setting tools for
straddle packers involve components such as a top section (where
the power module normally is located), a centre rod and a bottom
collapsible mandrel initially being held expanded and in place by
means of a shear pin arrangement. When setting a straddle packer by
means of prior art setting tools, the top section and the bottom
mandrel are forced towards each other by means of the centre rod,
powered by a pyrotechnical charge, an electric pump, wellbore
pressure, pressurised gas chambers or similar. Once the required
force is applied in order to set anchor(s) and packer elements, the
shear pin arrangement of the bottom mandrel shears, whereupon the
mandrel collapses and becomes retrievable through the straddle
packer body. Because of this arrangement with the mandrel and
feedtrough/centre rod, the setting tool has to be made of similar
length as the straddle packer itself.
[0035] Due to the novel setting device/system and method according
to a preferred embodiment of the present invention utilizing
communication means, the need for setting tool parts such as a
feed-trough rod and collapsible mandrel are at least partly
eliminated from the straddle packer setting tool.
[0036] In a preferred embodiment the communication means includes
means for transmitting and receiving wireless signals for
controlling the setting element of the straddle packer. In one
embodiment the wireless communications means includes at least one
transmitter and at least one receiver and/or at least one
transceiver.
[0037] In alternative embodiments of the invention, the
communication means associated with the activation of straddle
packer element(s) and/or anchor(s) could be direct means such as
electrical, fibreoptic or hydraulic connections. Further, said
means for activation could also comprise sensors monitoring changes
or desired set-values of wellbore parameters. The latter could as
an example be a pressure or temperature sensor, associated with a
timer device that trigger element/anchor activation at a
predetermined time after a sensor reading a defined set-value.
[0038] One of the most typical applications would be the
installation of straddle packers in subsea wells, but could also be
the case of setting straddle packers, or other tools, in other
types of wells, in order to save cost, time, overcome rigging
constraints and similar.
[0039] In one embodiment of the invention, pulling tools intended
for the retrieval of a straddle packer could be provided with
similar transmitter systems as the setting tool described above,
and straddle packers provided with a second receiver and activation
system to facilitate retrieval of the packer in a similar fashion
and philosophy as for the setting process.
[0040] In one embodiment the axial length of the setting tool is
less than the axial length of the straddle packer. The axial length
of the setting tool is in one embodiment less than three quarter of
the axial length of the straddle packer. In another embodiment the
axial length of the setting tool is less than one half of the axial
length of the straddle packer. In still another embodiment the
axial length of the setting tool is less than one quarter of the
axial length of the straddle packer.
[0041] In one embodiment at least one separate setting element is
integrated in a portion of a tubular body of the straddle
packer.
[0042] In a second aspect of the present invention there is
provided a method for isolating a section of a wellbore, the method
including setting a straddle packer using a system for selectively
setting of at least one upper packer element, at least one lower
packer element and at least one anchoring device of the straddle
packer, wherein the method comprising operating at least one
setting element of the setting tool independent from other setting
elements.
[0043] The invention will now be described in more detail by means
of the attached figures. Do note that despite the fact that the
figures illustrate one particular application and technique in
order to deploy, intervene and in stall a long straddle packer in a
subsea well by means of RLWI techniques (subsea wireline from a
vessel without riser to the surface), this does not indicate any
restrictions to the invention. A person skilled in the art would be
able to identify variable ways of performing steps of the operation
described in the figures as well as transfer the system and method
principles to other applications of similar nature.
[0044] It is also imaginable a device for operating elements such
as valves, barrier elements and actuators related to wellbore
tooling, the device including systems for selectively operating at
least one of said valves, barrier elements and/or actuators,
wherein at least one system element can be operated independent
from other system elements.
[0045] It is further imaginable a method for operating elements
such as valves, barrier element and actuators related to wellbore
tooling, the device including systems for selectively operating at
least one of said valves, barrier elements and/or actuators,
wherein at least one system element being operated independent from
other system elements.
[0046] Hereinafter, non-limiting examples of preferred embodiments
are described and visualized in the accompanying drawings, in
which:
[0047] FIG. 1a illustrates schematically a portion of a prior art
straddle packer.
[0048] FIG. 1b illustrates schematically a portion of a straddle
packer according to a preferred embodiment of the invention.
[0049] FIG. 2 illustrates schematically and in a larger scale a
bottom setting element of the straddle packer according to one
embodiment of the present invention.
[0050] FIGS. 3a and 3b illustrates each, in a smaller scale, a
system module utilized in a preferred embodiment for intervening a
long straddle packer in a subsea well.
[0051] FIG. 4 illustrates in a smaller scale an initial stage of an
intervention process, when lowering a long straddle packer trough
the open sea.
[0052] FIG. 5 illustrates in substantially the same scale as in
FIGS. 3a and 3b, a first step of system deployment, i.e. bringing
the straddle packer from the marine environment into the
pressurised well environment.
[0053] FIG. 6 illustrates a second step of system deployment
[0054] FIG. 7 illustrates a third step of system deployment.
[0055] FIGS. 8a and 8b illustrates system installation in the
down-hole part of the well.
[0056] FIG. 9 illustrates an installed straddle packer in a
producing well.
[0057] FIG. 10 illustrates retrieving the main part of the setting
tool for a preferred embodiment of the invention from the well.
[0058] In the figures the same or similar components are designated
with the same reference numerals.
[0059] FIGS. 1a and 1b illustrate in a schematic manner an overall
system according to prior art and according to a preferred
embodiment of the invention, respectively, in order to facilitate
the description of innovative aspects. Both FIGS. 1a and 1b
describes a straddle packer 1 (reference numeral 1' for the prior
art straddle packer), provided with a top packer element 2, a
bottom packer element 3 and an anchor 4. Other elements known to be
associated with straddle packers, such as additional anchoring
modules and/or expansion joints are not shown in FIGS. 1a and 1b,
but a person skilled in the art would easily recognise that such
modules as well as other system modules as per se could be included
in a preferred embodiment of the invention. The straddle packers 1
and 1' in FIGS. 1a and 1b are both prepared for setting.
[0060] In the embodiment of the novel art straddle packer 1 in FIG.
1b, an as per se setting tool 100 comprises the top section 5, a
collapsible mandrel 9, and a limited length feed-through rod 8. The
cable head 6 and cable 7 are also illustrated to outline the
complete well service tool string. An important feature of the
invention is that for this preferred embodiment, the setting tool
system for the straddle packer comprises more than one setting
unit/element, and that said setting elements can be operated
independent of each other. For the embodiment described in FIG. 1b,
the as per se setting tool top section 5 is anchored to the upper
sections of the straddle packer 1 by means of a collapsible mandrel
9, through the limited length feed-through rod 8. Unlike prior art
straddle packer 1' that utilises a long feed-through rod 8' being
substantially coextensive with the length of the straddle packer 1,
the feed-through rod 8 for the straddle packer 1 according to the
present invention runs through the top section only of the straddle
packer 1. The feature of axial length L1 of the as per se setting
tool 100 being significantly shorter than the axial length L2 of
the straddle packer 1 is one essential characteristic for the
present invention.
[0061] Preferably, for this embodiment of straddle packer 1 of the
invention, the axial length L1 of the as per se setting tool 100 is
less than three quarter of the axial length L2 of the straddle
packer 1.
[0062] More preferably, for this embodiment of straddle packer 1 of
the invention, the axial length L1 of the as per se setting tool
100 is less than one half of the axial length L2 of the straddle
packer 1.
[0063] Most preferably, for this embodiment of straddle packer 1 of
the invention, the axial length L1 of the as per se setting tool
100 is less than one quarter of the axial length L2 of the straddle
packer 1.
[0064] In the embodiment shown, there is a bottom setting element
10 in the bottom section of the straddle packer 1. The bottom
setting element 10 is used for setting of the bottom packer element
3. For the setting of straddle packer 1, the setting tool 5 is
provided with a transmitter 11 of a wireless signal that is used to
transmit an activation command 12 to the bottom setting element 10
in order to set this by means of expansion. The bottom setting
element 10 is provided with a receiver and activation unit 14 that
detects the received setting command 13, translates it as known per
se tiates the setting sequence of the bottom packer element 3.
[0065] In the embodiment shown in FIG. 1b, the bottom setting
element 10 is a centred device, i.e. the bottom setting element 10
is substantially coaxial with the straddle packer.
[0066] The bottom setting element 10 could be designed to disappear
by means of disintegration, mechanical retraction or other means as
known per se after the bottom packer element 3 is set.
[0067] In another embodiment of the invention, shown in FIG. 2, the
bottom setting element 10 is built into a wall of the straddle
packer 1. In this embodiment, the bottom setting element 10 may be
regarded as a setting tool being dependent upon the as per se
setting tool 100 comprising communication means. Further, in other
embodiments of the invention, the setting tool top section 5 could
be of the same type as the bottom setting element 10, associated
with similar communication and activation means. Further, anchor(s)
4 could be associated with similar type setting element 10,
associated with similar communication and activation means. In a
general embodiment, all elements to be operated (packer elements,
anchors, valves etc) can be operated partly or totally independent
from other elements to be operated, using similar type setting
element 10, associated with similar communication and activation
means.
[0068] In one embodiment of the invention, the bottom element 10
forms a seal against the inner wall of the straddle packer 1, so
that fluids can not flow into the straddle packer 1 from below
during deployment into a subsea well. This feature could be
required in subsea deployment operations where pressure seals
between the potentially high-pressurised wellbore and the marine
environment on the outside of the wellhead might be a necessity. In
yet another embodiment of the invention, such seal requirement is
achieved by means of a sealing function between the setting tool 5
and the top section of the straddle packer 1. A person skilled in
the art will be familiar with ways of obtaining such a seal. For
this reason, sealing elements are not shown in detail in the
drawing.
[0069] FIG. 2 illustrates an alternative embodiment of the bottom
setting element 10 of the straddle packer 1. Note that only a
portion of the straddle packer 1 wall located at the right side of
the straddle packer centre line CL is shown in FIG. 2. In this
embodiment the receiver 14 is reads the received setting command
13. An electronics module 21 interrogates the receiver 14 in order
to interpret registrations from the sensor/receiver 14. When there
is a positive detection of an activation signal, i.e. an initiating
command, the electronics emit a signal/impulse to fire a detonator
22 that again ignites a pyrotechnic charge 23 that is adapted to
fit inside a slot in the wall of the straddle packer 1. As the
pyrotechnic charge 23 burns, it generates gas that imposes a large
pressure on a piston 24. The piston 24 is forced downwards, and
pushes a fluid 25, such as hydraulic oil, downwards. Then said
fluid 25 forces a wedge-shaped element 26 downwards and forces this
to set a packer element 3 against the tubing wall 27.
Alternatively, the wedge shaped element 26 is replaced by means of
an alternative element with similar function--i.e. to compress and
support the bottom packer element 3. The receiver 14 and associated
electronics module 21 is powered by means of a battery module
28.
[0070] Further to FIG. 2; this only illustrates one of a variety of
ways of designing a system that sets (in this case) the lower
packer element 3 of the straddle (or activates any element in a
general application). Other possible methods that could be applied
involve: [0071] A secondary thermal battery that operates a motor,
which again applies force on the mechanic components that force the
lower packer element 3 to set. [0072] A pilot valve or similar,
exposing a "power chamber" to well fluids which again works against
an atmospheric chamber to create the necessary forces to operate
mechanic components that force the lower packer element 3 to set.
[0073] A pilot valve or similar, exposing a "power chamber" to a
high pressurised gas reservoir that forms part of the tool design,
which again works against an atmospheric chamber to create the
necessary forces to operate mechanic components that force the
lower packer element 3 to set. [0074] Any relevant method for
directly and/or indirectly generating a force on a packer element
in an autonomous manner. [0075] Any combination of the above
methods, combined with a valve or another type of barrier (as
indicated by means of bottom setting element 10 in FIG. 1b),
located in the bottom section of the straddle packer, said
valve/barrier opens or "disappears" in other manners upon a
finalised setting of the bottom packer element. [0076] A pump that
inflates the lower packer element by means of pumping well fluids
into the lower packer element 3, by use of a built-in reservoir.
[0077] Any method for setting a packer element as known per se.
[0078] Self-swelling packers.
[0079] FIGS. 3a and 3b illustrates two essential system modules of
a preferred embodiment for intervening a long straddle packer 1 in
a subsea well.
[0080] The apparatus shown in FIG. 3a is merely a preferred
embodiment of the invention disclosed in NO 20051257, including the
following modules and components: [0081] Subsea Deployment
Lubricator Module (SDLM) 31, comprising a dynamic seal 32, an
anti-blowout device 33 and flush lines 34a and 34b. [0082] Lower
Riser Package (LRP) 35, comprising test valves (gate valves) 36a
and 36b, and a safety head (shear valve) 37. [0083] A hang-off
spool 38, comprising a hang off profile 39 (not applied for this
application specifically, but a perceived general component in the
seabed stack for operations involving the SDLM 31). [0084] The
wellhead 300. [0085] A small section of lubricator riser 301 (might
not be needed neither in a preferred embodiment of this invention
nor in the invention disclosed in NO 20051257). [0086] The LRP 35
is in this example also hooked up to a kill line 302.
[0087] FIG. 3b shows the schematics of a preferred straddle packer
1 to be used in conjunction with the SDLM 31 and other seabed stack
components shown in FIG. 3a. As also described for FIG. 1b, the
straddle packer 1 is provided with a top packer element 2, a bottom
packer element 3 and an anchor 4. The as per se setting tool 100
comprises a top section 5, a collapsible mandrel 9, and a limited
length feed-through rod 8. The cable head 6 and cable 7 are also
illustrated. In the bottom of the straddle packer 1, there is a
bottom setting element 10, used for setting of the bottom packer
element 3. The "as per se" setting tool 100 top setting element 5
is provided with a transmitter 11 of a wireless signal that is used
to transmit a setting command 12 (see FIG. 1b) to the bottom
setting element 10. The latter is provided with a receiver and
activation unit 14 that detects the received setting command (see
FIG. 1b) translates it and initiates the setting sequence of the
bottom packer element 3. In this embodiment of the invention, the
bottom setting element 10 is built into the wall of straddle packer
1.
[0088] A person skilled in the art would recognise that for
alternative embodiments, the transmitter 11 could be located
elsewhere than on the as per se setting tool 100 top setting
element 5, as a module of its own or as part of other system
modules. This is not further described herein.
[0089] In other embodiments of the invention, the transmitter 11
and receiver 14 are replaced by transceivers. In this way, one can
by means of active two-way communication and/or passive monitoring
of parameters related to the activation get a positive feedback
that the bottom setting element has received a setting command 12
and executed the setting process. In yet another embodiment of the
invention, the transceiver located in the top setting element
includes a sensor that can record any indications that the setting
process has taken place. An example of such is a quartz crystal
sensor that "listens" for the sound created when detonating e.g.
the detonator 22 shown in FIG. 2.
[0090] FIG. 4 illustrates an initial stage of a subsea intervention
process from a RLWI vessel. More specifically, FIG. 4 illustrates
the process of lowering a long straddle packer 1 assembly trough
the open sea. A surface vessel 41 tailored for riserless well
intervention (RLWI) is used in conjunction with a seabed stack 42,
comprising a SDLM 31, LRP 35, hang-off spool 38 and, in this
embodiment, a small section of lubricator riser 301 in order to
deploy a long straddle packer 1 into the subsea well 43. It should
be noted that, at the given stage of the deployment sequence, the
downhole safety valve 44 of subsea well 43 is closed and pressure
is bled off above it. Also, in order to provide the required amount
of well barriers, the test valves (gate valves) 36a and 36b are
closed.
[0091] Steps required for flushing, pressure testing as well as
monitoring parameters are not described in detail here. However,
any person skilled in the art would be able to identify the need
for such actions as well as the most appropriate location of
related system components and also the most relevant sequence of
operation with respect to these actions. Flushing, pressure testing
and monitoring systems could be located anywhere on the seabed
stack, for example built into the SDLM 31, the LRP 35, the hang off
spool 38 or other location or combination of locations.
[0092] FIG. 5 illustrates the first step of system deployment, i.e.
bringing the straddle packer 1 assembly from the marine environment
into the pressurised well environment. As soon as the bottom of the
straddle packer 1 assembly enter the seabed stack 42, a positioning
procedure is performed in order to position the bottom packer
element 3 and the bottom setting element 10 correct with respect to
the test valves (gate valves) 36a and 36b and the dynamic seal 32,
an anti-blowout device 33 of the SDLM 31. Said positioning is
performed in a way known per se.
[0093] Upon having positioned the straddle packer 1 correctly, the
dynamic seal 32, and an anti-blowout device 33 of the SDLM 31 is
engaged to the tubing wall of the straddle packer 1. A person
skilled in the art will understand that it is of importance that no
mechanical engagement is made to the bottom packer element 3 and
the bottom setting element 10 in order to avoid damage to these.
Hence, a proper positioning procedure is performed prior to
engagement. However, in other embodiments of the invention, the
bottom packer element 3 and bottom setting element 10 are built
robust enough or with a sufficient protection to allow for
mechanical engagement onto these sections as well, reducing the
requirements for a strict positioning of the straddle packer 1.
[0094] FIG. 6 illustrates the second step of system deployment.
Subsequent the required flushing, pressure testing and monitoring
actions, the test valves (gate valves) 36a and 36b are opened and
the straddle packer 1 is lowered into the wellbore. The lowering
operation is stopped prior to so the anchor 4 entering the dynamic
seal 32 of the SDLM 31. It is important to stop at such location as
the anchor 4 might cause damage to the dynamic seal 32 if lowered
into this. Also, such event could cause a breach of barrier
requirements. In a preferred embodiment of the invention,
positioning systems and/or mechanical or other "halt" systems are
included to facilitate the correct positioning of the anchor 4 with
respect to the dynamic seal 32. Upon finalising a correct
positioning, the top of the cable head 6 should be fully contained
inside the lubricator riser 301. In a preferred embodiment of the
invention, there is no need for the lubricator riser as the full
top sections of the toolstring can be contained within the seabed
stack (i.e. within the top section of the SDLM 31). A grease
injection head 62 is mounted on top of the lubricator riser 301.
After flushing, pressure testing and monitoring are performed, a
third step of system deployment as illustrated in FIG. 7,
commences.
[0095] FIG. 7 illustrates an embodiment of the invention, where the
dynamic seal 32 and the anti-blowout device 33 are radially
disengaged from the straddle packer 1 whereupon this is run into
the wellbore in order to perform the desired operation.
[0096] FIGS. 8a and 8b illustrates system installation in the
downhole part of the well. More specifically, FIG. 8a illustrates
the straddle packer 1 being positioned with respect to an upper
perforated section 80 by aligning the bottom packer element 3 with
a non-perforated section 80' of a casing/liner 81. The
non-perforated section 80' is located below said upper perforated
section 80. The top packer element 2 and anchor 4 are aligned with
a non-perforated section 80'' of the wells casing/liner 80 above
the perforated section 80. Hence, the straddle packer 1 is aligned
in order to fully seal off and isolate perforation 80. FIG. 8b
illustrates the straddle packer 1 after setting/engagement of
bottom packer element 3, top packer element 2 and anchor 4. Also,
FIG. 8b illustrates emission of a wireless activation signal 12
from transmitter 11 of the setting tool 5. The activation signal 12
is received as signal 13 by the receiver and activation unit 14
that is located in the proximity to the bottom packer element 3.
Upon receiving a correct message 13, receiver and activation unit
14 initiates and performs the process of setting bottom packer
element 3, either directly or indirectly through a bottom setting
element 10 as illustrated in FIGS. 1 and 2.
[0097] As described earlier, the straddle packer 1 assembly could
comprise more than one anchor 4. In particular, for a preferred
embodiment, a bottom anchor 4 would enable an installation
procedure where the bottom packer element 3 and a bottom anchor
(not shown) is set first, whereupon a pull test by means of
applying tension to the cable 7 is performed to verify a successful
setting of this part of the straddle packer 1. Subsequently, the
top packer element 2 and anchor 4 can be set. Further, top and
bottom anchors are commonly used if an expansion joint is included
in the straddle packer 1. Such expansion joints could be required
if expected temperature differences in the well exceed certain
limits, or if the straddle packer 1 is installed across expansion
joints in the well to fix leakages. A person skilled in the art
would recognise all such considerations, and no further reference
is given herein.
[0098] FIG. 9 illustrates schematically an installed straddle
packer 1 in a producing well after the as per se setting tool 100
with associated elements are retrieved, and production of the well
is re-established. As can be seen, no fluids will now be produced
from the upper perforated section 80, whereas fluids from the lower
lying zone 91 are produced through straddle packer 1.
[0099] FIG. 10 illustrates retrieval of the setting tool assembly
from the well. FIG. 10 shows the as per se setting tool 100 and
accessories after retrieval into, the top section of the seabed
stack 42. Further, the figure shows the lower end of the seabed
stack. After retrieval and positive indication that the entire
straddle packer setting string 101 is positioned in a defined top
section of the seabed stack 42, valves 36a and 36b are shut.
Thereupon, appropriate flushing, pressure testing and monitoring
actions are performed prior to disconnecting the grease injection
head 62. Then, relevant steps described in the prior sections are
reversed in order to retrieve the packer setting string 101 and
seabed stack 42 to the surface and thereby finalizing the straddle
packer installation operation.
* * * * *