U.S. patent application number 15/700222 was filed with the patent office on 2018-03-22 for packer.
The applicant listed for this patent is MorphPackers Limited. Invention is credited to William Luke McElligott, Cameron Hill Radtke.
Application Number | 20180080303 15/700222 |
Document ID | / |
Family ID | 57288872 |
Filed Date | 2018-03-22 |
United States Patent
Application |
20180080303 |
Kind Code |
A1 |
Radtke; Cameron Hill ; et
al. |
March 22, 2018 |
Packer
Abstract
Method and apparatus for delivering fluid at a high pressure to
a predetermined location in a downhole environment. A tool
including a chamber is located in a wellbore with the chamber being
at a first chamber pressure and first chamber volume. Fluid is
introduced to the chamber through a first fill mechanism to
increase pressure in the chamber and close the chamber at a second
chamber pressure and a second chamber volume. Pumping fluid through
the tool at a pressure greater than the second chamber pressure
activates a pressure intensifier in a second fill mechanism and
fluid at a multiplied pressure is added to the chamber. The chamber
then contains fluid at an increased third chamber pressure and
third chamber volume. An embodiment of a packer being set using the
apparatus and method is described.
Inventors: |
Radtke; Cameron Hill;
(Aberdeen, GB) ; McElligott; William Luke;
(Aberdeen, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MorphPackers Limited |
Aberdeen |
|
GB |
|
|
Family ID: |
57288872 |
Appl. No.: |
15/700222 |
Filed: |
September 11, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 33/127 20130101;
E21B 33/1272 20130101; E21B 34/10 20130101; E21B 33/1212 20130101;
E21B 2200/06 20200501; E21B 23/06 20130101 |
International
Class: |
E21B 33/127 20060101
E21B033/127; E21B 23/06 20060101 E21B023/06; E21B 34/10 20060101
E21B034/10; E21B 33/12 20060101 E21B033/12 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 16, 2016 |
GB |
GB1615789.3 |
Claims
1. A method of delivering fluid at an increased pressure to a
chamber located in a wellbore, the method comprising the steps: (a)
locating a tool including a chamber in a wellbore, the chamber
being at a first chamber pressure and first chamber volume; (b)
opening the chamber and introducing fluid at a first operating
pressure to the chamber; (c) closing the chamber, the chamber then
being at a second chamber pressure and a second chamber volume; (d)
activating a pressure intensifier; and (e) opening the chamber and
introducing fluid from the pressure intensifier into the chamber,
the chamber then being at a third chamber pressure and a third
chamber volume.
2. A method according to claim 1 wherein the step of closing the
chamber is achieved via a valve.
3. A method according to claim 2 wherein the valve is a sliding
sleeve valve.
4. A method according to claim 2 wherein the valve is a check
valve.
5. A method according to claim 1 wherein the third chamber pressure
is greater than the second chamber pressure which is greater than
the first chamber pressure.
6. A method according to claim 1 wherein the third chamber volume
is greater than the second chamber volume which is greater than the
first chamber volume.
7. A method according to claim 1 wherein the second and third
chamber volumes are the same with both greater than the first
chamber volume.
8. A method according to claim 1 wherein the first, second and
third chamber volumes are constant.
9. A method according to claim 1 wherein the first operating
pressure is casing pressure present in the wellbore.
10. A method according to claim 1 wherein the first operating
pressure is a pump pressure delivering fluid from surface.
11. A method according to claim 1 wherein the method includes the
step of closing the chamber when the third chamber pressure and
third chamber volume is reached.
12. Apparatus for delivering fluid at an increased pressure to a
chamber located in a wellbore, being a downhole arrangement
comprising: a first fill mechanism including valve means to control
fluid flow into the chamber; a second fill mechanism including a
pressure intensifier and an output, the output arranged to match an
input of the chamber; wherein the first fill mechanism is actuated
by fluid flow at a first operating pressure through the downhole
arrangement to allow fluid flow into the chamber and the second
fill mechanism is actuated at a second operating pressure, wherein
the second operating pressure is greater than the first operating
pressure.
13. Apparatus according to claim 12 wherein the downhole
arrangement comprises a tubular body providing a throughbore; the
tubular body has an outer surface and an inner surface and the
chamber is formed between the outer surface of the tubular body and
a morphable sleeve arranged around the tubular body; and fastening
means is present at longitudinal ends of the chamber to hold the
morphable sleeve to the tubular body.
14. Apparatus according to claim 12 wherein the valve means
comprises at least one fluid passageway through the tubular body
and a sliding seal arrangement at an outer surface, the sliding
seal having a sealing surface to provide a seal on the outer
surface and prevent fluid flow from the throughbore to the chamber
and wherein the sliding seal arrangement is operated by the fluid
flow via a first fluid passageway through the tubular body.
15. Apparatus according to claim 14 wherein the sealing surface is
co-linear with a central, longitudinal axis of the tubular
body.
16. Apparatus according to claim 14 wherein the first fluid
passageway is a conduit through the body between a first port at
the inner surface of the tubular body and a second port at the
outer surface of the tubular body.
17. Apparatus according to claim 16 wherein there is a second fluid
passageway through the body between a third port at the outer
surface of the tubular body and a fourth port at the outer surface
of the tubular body, the third and fourth ports being spaced apart
longitudinally on the outer surface of the body.
18. Apparatus according to claim 16 wherein a housing is located on
the outer surface wherein the second port exits into the housing
and the sealing surface is arranged in the housing.
19. Apparatus according to claim 18 wherein the sliding seal is
arranged in the housing in a first configuration wherein fluid can
flow from the second port to the third port to fill the chamber and
a second configuration wherein the sealing surface seals a port to
prevent fluid flow to the chamber.
20. Apparatus according to claim 13 wherein the second fill
mechanism is formed from the tubular body and the pressure
intensifier comprises: an elongate mandrel defining the throughbore
bore into which fluid is delivered, the mandrel being co-axially
located within an elongate hollow outer cylindrical body; at least
one annular piston extending inwardly from the cylindrical body
across the annular bore to the mandrel and shaped such that a
discreet fluid receiving void is created between an active surface
of the piston and the elongate mandrel; at least one input port to
enable fluid communication between the inner bore and the fluid
receiving void; at least one stop located on an outer surface of
the mandrel to limit travel of each piston; trapped fluid located
in an enclosure of the annular bore between an opposing surface of
a first piston and a first stop; wherein at least one delivery port
exits the enclosure to deliver the trapped fluid at a greater
pressure than the pressure of fluid delivered through the inner
bore.
Description
[0001] The present invention relates to an improved apparatus and
method for delivering fluid at a high pressure to a predetermined
location in a downhole environment and in particular, though not
exclusively, to inflate a packer in a wellbore.
[0002] Packers are well known in the exploration and production of
oil and gas wells and used to form a seal between tubular members,
such as a liner, mandrel, production tubing and casing or between a
tubular member, typically casing, and the wall of an open borehole.
The seal prevents fluid flow in the annulus and can therefore be
used to isolate portions of the annulus and allow access to
distinct sections of the formation. Packers may also anchor an
inner tubular to an outer tubular or borehole wall.
[0003] One type of packer is the inflatable packer. In an
inflatable packer, a bladder, skin or sleeve is inflated by fluid
pressure to expand an outer wall of the bladder, skin or sleeve
into contact with the borehole wall or another tubular, such as
casing, located in the wellbore. Early inflatable packers were
formed from a rubber bladder with elastomeric seals being developed
later. These materials can degrade particularly in the presence of
chemicals injected in the wellbore. Metals are now being used which
can expand under hydraulic fluid pressure to morph against the
borehole wall or other casing. An example of a packer using this
technology is described in WO2016/055775.
[0004] There are a number of requirements to achieve successful
inflation of a packer downhole. Firstly, inflation must not occur
until the packer has reached its location and `setting` of the
packer is needed. Most packers are set when a predetermined
pressure is reached in the wellbore and thus the packer must not
inflate before this pressure is reached. Secondly, ample fluid
pressure must be applied to the inner surface of the outer wall to
cause radial expansion sufficient for the outer wall to contact a
wellbore wall such as the borehole wall or outer tubular and create
a seal. Obviously the fluid pressure needs to be greater than the
pressure in the well annulus for expansion to occur, and for
elastomeric packers only a small differential of a few thousand psi
would be needed, however to morph metal downhole requires greater
setting pressures typically in excess of ten thousand psi. Finally,
the setting pressure needs to be maintained in the inflated packer
so that the seal is not breached.
[0005] The need to deliver fluid at high pressures to a deep
location in a well poses difficulties. When pumping from surface it
is known that fluid pressure decreases with depth which makes
calculating pressure at depth inadequate to ensure an accurate
setting pressure is reached or the pump pressure at surface needed
to ensure setting pressure is reached at depth is beyond the
capability of available pumps used at surface. Additionally, for
many well designs, it is undesirable to pump high pressure fluid
through the tubing string.
[0006] Hydraulic fluid delivery tools have been developed which can
be run into a string from surface by means of coiled tubing or
other suitable method. U.S. Pat. No. 7,017,670 presents such a
tool, but this still relies on high pressure fluid being pumped
from surface with many of the same disadvantages as described
above.
[0007] To create high fluid pressure in the wellbore, pressure
intensifiers are used. WO2016/051169 describes a pressure
intensifier for morphing tubulars downhole. An elongate mandrel
defines an inner bore, being co-axially located within an elongate
hollow outer cylindrical body to form a co-axial annular bore
therebetween. Pistons are mounted upon the mandrel with each piston
having an annular fluid facing face extending across the annular
bore, with fluid communication between the inner bore and the
annular bore to act upon each face. Stops are located on an inner
surface of the outer cylindrical body to limit travel of each
piston. A morph fluid is located in the annular bore between an
opposing face of a first piston and a first stop, with the first
stop having delivery ports to deliver the morph fluid at a greater
pressure than the pressure of fluid delivered through the inner
bore. The morph fluid is effectively held in an enclosure and when
an operating fluid pressure is applied through the bore, the
pistons are released to operate in series, multiplying the pressure
applied to the enclosure and consequently to the fluid in the
enclosure. The morph fluid can be used to inflate a packer.
However, a disadvantage of this arrangement is that the enclosure
must be made large enough to hold a sufficient volume of fluid to
inflate the packer and achieve the setting pressure in the packer
when inflated.
[0008] It is an object of an embodiment of the present invention to
provide a is method of delivering fluid at an increased pressure to
a chamber located in a wellbore which mitigates at least some of
the disadvantages of the prior art.
[0009] It is a further object of an embodiment of the present
invention to provide apparatus for delivering fluid at an increased
pressure to a chamber located in a wellbore which does not require
pumping of fluid at the increased pressure from surface.
[0010] According to a first aspect of the present invention there
is provided a method of delivering fluid an increased pressure to a
chamber located in a wellbore, the method comprising the steps:
[0011] (a) locating a tool including a chamber in a wellbore, the
chamber being at a first chamber pressure and first chamber volume;
[0012] (b) opening the chamber and introducing fluid at a first
operating pressure to the chamber; [0013] (c) closing the chamber,
the chamber then being at a second chamber pressure and a second
chamber volume; [0014] (d) activating a pressure intensifier; and
[0015] (e) opening the chamber and introducing fluid from the
pressure intensifier into the chamber, the chamber then being at a
third chamber pressure and a third chamber volume.
[0016] By staging the pressure increases in the chamber, the fluid
introduced by the pressure intensifier adds to the pressure in the
chamber to provide a cumulative pressure and volume increase within
the chamber.
[0017] Preferably, the step of closing the chamber is achieved via
a valve. The valve may be a sliding sleeve valve. Alternatively the
valve may be a check valve. In this way, the pressure cannot drop
within the chamber so that a cumulative pressure increase
occurs.
[0018] Preferably, the third chamber pressure is greater than the
second chamber pressure which is greater than the first chamber
pressure. This ensures a cumulative pressure increase.
[0019] Preferably, the third chamber volume is greater than the
second chamber volume which is greater than the first chamber
volume. A cumulative increase in volume provides a method for
inflating a packer in a wellbore, where the first chamber volume
represents an uninflated packer, the second chamber volume
represents a partially inflated packer and the third chamber volume
represents an inflated or set packer. In this way, the pressure and
volume in the final enclosure of the pressure intensifier does not
require to be sufficient to fully inflate the packer but merely to
top it up as the packer is already partially inflated when the
pressure intensifier is activated.
[0020] In an alternative embodiment, the second and third chamber
volumes are the same. This may occur in a metal sleeved packer were
inflation is achieved using the fluid introduced at step (b) and
the second chamber pressure is sufficient to elastically deform the
outer metal sleeve of the packer. The fluid introduced by the
pressure intensifier is then used to plastically deform the outer
metal sleeve so that it retains its shape in the inflated
position.
[0021] Optionally, the first, second and third chamber volumes may
be constant. In this way, the greatest cumulative pressure can be
delivered to the chamber. This fluid pressure may actuate a tool in
the wellbore.
[0022] The first operating pressure may be casing pressure present
in the wellbore. Alternatively, the first operating pressure may be
a pump pressure delivering fluid from surface.
[0023] Preferably the method includes the step of closing the
chamber when the third chamber pressure and third chamber volume is
reached. In this way, the high pressure is isolated and for a
packer, deflation is prevented. Thus the setting pressure can be
maintained in an inflated packer so that the seal is not
breached.
[0024] According to a second aspect of the present invention there
is provided apparatus for delivering fluid at an increased pressure
to a chamber located in a wellbore, being a downhole arrangement
comprising: [0025] a first fill mechanism including valve means to
control fluid flow into the chamber; [0026] a second fill mechanism
including a pressure intensifier and an output, the output arranged
to match an input of the chamber; wherein the first fill mechanism
is actuated by fluid flow at a first operating pressure through the
downhole arrangement to allow fluid flow into the chamber and the
second fill mechanism is actuated at a second operating pressure,
wherein the second operating pressure is greater than the first
operating pressure.
[0027] In this way, a cumulative fluid pressure can be achieved in
the chamber via the first fill mechanism and then by the pressure
intensifier.
[0028] Preferably the downhole arrangement comprises a tubular body
providing a throughbore. The tubular body has an outer surface and
an inner surface. In this way fluid can be pumped down the
throughbore to operate the fill mechanisms.
[0029] Preferably the chamber is formed between the outer surface
of the tubular body and a morphable sleeve arranged around the
tubular body. Fastening means may be present at longitudinal ends
of the chamber to hold the morphable sleeve to the tubular body. In
this way, the downhole arrangement provides a packer with integral
pressure intensifier.
[0030] Preferably the valve means is a check valve. In this way the
first fill mechanism is a simple valve which lets valve fluid into
the chamber but does not let the fluid exit the chamber. More
preferably the valve means includes a rupture disc set to rupture
at the first operating pressure. In this way the first stage fill
of the chamber can only begin at the first operating pressure. This
prevents any inflation of the packer occurring before a desired
pressure is reached in the throughbore.
[0031] In an embodiment, the valve means comprises at least one
fluid passageway through the tubular body and a sliding seal
arrangement at an outer surface, the sliding seal having a sealing
surface to provide a seal on the outer surface and prevent fluid
flow from the throughbore to the chamber and wherein the sliding
seal arrangement is operated by the fluid flow via a first fluid
passageway through the tubular body.
[0032] Preferably, the sealing surface is co-linear with a central,
longitudinal axis of the tubular body.
[0033] Preferably, there are first and second fluid passageways
through the body. Preferably, the first fluid passageway is a
conduit through the body between a first port at an inner surface
of the tubular body and a second port at the outer surface of the
tubular body. Preferably the second fluid passageway is a conduit
through the body between a third port at an outer surface of the
tubular body and a fourth port at the outer surface of the tubular
body, the third and fourth ports being spaced apart longitudinally
on the outer surface of the body. In this way, the throughbore can
be kept clear of obstructions only requiring a first port at the
outer surface of the throughbore.
[0034] There may be a plurality of first fluid passageways. There
may be a plurality of second fluid passageways. Preferably the
plurality of fluid passageways are equidistantly arranged
circumferentially around the longitudinal axis. In this way, the
conduits may be narrow in diameter to ease machining thereof but a
sufficient volume of fluid flow can be achieved through the body to
fill the chamber.
[0035] Preferably, a housing is located on the outer surface
wherein the second port exits into the housing and the sealing
surface is arranged in the housing. The housing may be a sleeve
around the body and the sliding seal may be a sliding sleeve.
Alternatively the housing may be local to the second port with the
sliding seal being a piston arranged in the housing. In this way,
the sliding seal is contained so that fluid may act upon it.
[0036] Preferably, the third port exits from the housing and fluid
exiting the fourth port is used to fill the chamber. The fourth
port may exit directly into the chamber. Alternatively, there may
be a third fluid passageway from the fourth port to the chamber. In
this way, the fill mechanism can be spaced longitudinally apart
from the chamber. By separating the housing and the chamber the
downhole arrangement can be thin walled to aid deployment into a
well bore.
[0037] Advantageously, the sliding seal is arranged in the housing
in a first configuration wherein fluid can flow from the second
port to the third port to fill the chamber and a second
configuration wherein the sealing surface seals a port to prevent
fluid flow to the chamber. Preferably, in the second configuration
the sealing surface seals the third port. In this way, a fixed
fluid pressure can be retained in the chamber.
[0038] More preferably, the sliding seal moves between the first
configuration and the second configuration by the action of fluid
pressure against an end surface of the sliding seal. Thus the
sealing arrangement can be actuated by fluid flow through the first
passageway from the throughbore.
[0039] Preferably, the fill mechanism includes retaining means to
hold the sliding seal in the first configuration. The retaining
means may be a shear pin. In this way, the sliding seal can close
the passageway to the chamber at a preselected fluid pressure.
[0040] Preferably, the fill mechanism includes locking means to
keep the sliding seal in the second configuration. The locking
means may be a locking ring on the sliding seal which engages in a
recess in the housing. In this way, the chamber is sealed at a
preselected fluid pressure for the life of the well.
[0041] Advantageously, the housing is formed between the outer
surface of the tubular body and an inner surface of a sleeve
arranged around the tubular body. An end of the sleeve may abut or
include the chamber. In this way, the assembly is simple to
construct.
[0042] Preferably the second fill mechanism is formed from the
tubular body and the pressure intensifier comprises: [0043] an
elongate mandrel defining the throughbore bore into which fluid is
delivered, the mandrel being co-axially located within an elongate
hollow outer cylindrical body; [0044] at least one annular piston
extending inwardly from the cylindrical body across the annular
bore to the mandrel and shaped such that a discreet fluid receiving
void is created between an active surface of the piston and the
elongate mandrel; [0045] at least one input port to enable fluid
communication between the inner bore and the fluid receiving void;
[0046] at least one stop located on an outer surface of the mandrel
to limit travel of each piston; [0047] trapped fluid located in an
enclosure of the annular bore between an opposing surface of a
first piston and a first stop; [0048] wherein at least one delivery
port exits the enclosure to deliver the trapped fluid at a greater
pressure than the pressure of fluid delivered through the inner
bore.
[0049] In this way, a fluid pumped under pressure down the inner
bore will create a force used to move the at least one piston which
in turn causes delivery of the trapped fluid at increased pressure
to the chamber.
[0050] Preferably, there is a plurality of pistons arranged along
the cylindrical body. In this way, as the total force is the sum of
force from all the pistons, the pressure of the trapped fluid can
be increased without increasing the pressure of fluid pumped
downhole. Additionally, this arrangement allows the trapped fluid
to be injected into the chamber on a single stroke.
[0051] Preferably the plurality of pistons and the outer
cylindrical body are secured together and form a pressure
development mechanism which can move relative to the mandrel. By
retaining the mandrel in a fixed position and moving the pressure
development mechanism, the efficiency of the pressure intensifier
is increased by minimisation of the development of leak paths
causing pressure loss. In addition, provision of the moving parts
mounted in an annular arrangement around a fixed mandrel means that
the tool is easier to assemble i.e. it can be constructed in a `top
down` configuration.
[0052] Preferably, the delivery ports exiting the enclosure form
delivery conduits having an inner diameter less than the inner
diameter of the annular bore between each adjacent piston and stop.
Having delivery conduits of a narrower bore than that of the
annular bore causes a further increase in pressure in the trapped
fluid delivered along the delivery conduits.
[0053] Preferably, the intensifier includes a locking mechanism,
the locking mechanism being arranged to hold the pressure
development mechanism in a first position until actuation of the
pressure intensifier is required. In this way, the first fill
mechanism can operate before the second fill mechanism.
Advantageously, the locking mechanism is releasable at a
predetermined fluid pressure applied through the mandrel. More
preferably, the predetermined fluid pressure for release can be
adjustable. In this way, the fluid pressure for release can be set
in the field when other operable fluid pressures in the well will
be known.
[0054] Preferably, the locking mechanism is at least one shear pin
which secures the pressure development mechanism in a predetermined
position at an entry end of the pressure intensifier. Use of a
shear pin locking mechanism enables the pressure development
mechanism only to be actuated simply by provision of sufficient
hydraulic pressure when actuation is required. Advantageously, the
locking mechanism is accessible from an outer surface of the tool.
In this way, the pressure to shear the pin and activate the tool,
can be selected at any time dependent upon the pressure required to
activate other tools being used in the well.
[0055] In the description that follows, the drawings are not
necessarily to scale. Certain features of the invention may be
shown exaggerated in scale or in somewhat schematic form, and some
details of conventional elements may not be shown in the interest
of clarity and conciseness. It is to be fully recognized that the
different teachings of the embodiments discussed below may be
employed separately or in any suitable combination to produce the
desired results.
[0056] Accordingly, the drawings and descriptions are to be
regarded as illustrative in nature, and not as restrictive.
Furthermore, the terminology and phraseology used herein is solely
used for descriptive purposes and should not be construed as
limiting in scope. Language such as "including," "comprising,"
"having," "containing," or "involving," and variations thereof, is
intended to be broad and encompass the subject matter listed
thereafter, equivalents, and additional subject matter not recited,
and is not intended to exclude other additives, components,
integers or steps. Likewise, the term "comprising" is considered
synonymous with the terms "including" or "containing" for
applicable legal purposes.
[0057] All numerical values in this disclosure are understood as
being modified by "about". All singular forms of elements, or any
other components described herein including (without limitations)
components of the apparatus are understood to include plural forms
thereof.
[0058] Embodiments of the present invention will now be described,
by way of example only, with reference to the accompanying drawings
of which:
[0059] FIG. 1 is a cross-sectional schematic view through an
apparatus including a first and a second fill mechanism according
to an embodiment of the present invention;
[0060] FIGS. 2(a) and 2(b) are cross-sectional views through a
first fill mechanism first and second configurations, respectively,
for the apparatus of FIG. 1 according to an embodiment of the
present invention;
[0061] FIGS. 3(a) and 3(b) are cross-sectional views through a
second fill mechanism first and second configurations,
respectively, for the apparatus of FIG. 1 according to an
embodiment of the present invention; and
[0062] FIGS. 4(a), 4(b) and 4(c) are cross-sectional views through
wellbores illustrating the method of the present invention on an
(a) uninflated packer, (b) mainly set packer and (c) fully set
packer according to an embodiment of the present invention.
[0063] Reference is initially made to FIG. 1 of the drawings which
illustrates a downhole apparatus, generally indicated by reference
numeral 10, having a first fill mechanism 12 and a second fill
mechanism 14 to deliver fluid at an increased pressure to a chamber
16 in a tool 18 within a wellbore 20 according to an embodiment of
the present invention.
[0064] Downhole apparatus 10 presents a substantially tubular body
22 with a throughbore 24 arranged on a central axis 26. Throughbore
24 is of sufficient diameter to allow other tools and strings
through the apparatus 10. The throughbore 24 also provides access
for pumping fluids through the downhole apparatus 10. Downhole
apparatus 10 forms part of tool 18 in the preferred embodiment,
however apparatus 10 may be a separate tool or sub connected to a
further tool including the chamber 16.
[0065] The first fill mechanism 12 provides a controlled passageway
for fluid to travel into the chamber 16. The fluid will typically
be from the throughbore 24 having been pumped from surface or it
may be arranged to take fluid from the annulus 28 between the body
22 and the wellbore wall 30. Fluid may also be supplied to the
first fill mechanism 12 via a conduit (not shown) in the tool
string running to surface or by a hydraulic fluid delivery tool as
described in the prior art. The first fill mechanism is actuated to
open a port and let fluid enter the chamber 16. Actuation can be by
any suitable downhole actuation mechanism known to one skilled in
the art. For example it may be by a rupture disc set at a pressure
to match the fluid pressure needed to enter the chamber 16. When
sufficient fluid has entered the chamber 16 through the first fill
mechanism 12, the mechanism 12 will close preventing fluid exiting
the chamber and maintaining a second chamber pressure and second
chamber volume in the chamber 16. The second chamber pressure and
second chamber volume will typically be greater than the initial or
first chamber pressure and first chamber volume. Any suitable
downhole closure mechanism can be used as would be known by those
skilled in the art. For example, a simple check valve set at the
desired second chamber pressure can be used.
[0066] In the preferred embodiment the first fill mechanism 12 is
as illustrated in FIGS. 2(a) and 2(b). Fill mechanism 12 is
provided through the tubular body 22, to fill the chamber 16 with
fluid from the throughbore 24 of the tubular body 22, as shown in
FIG. 1.
[0067] Body 22 has an inner surface 25 which forms the wall of the
throughbore 24 and is co-linear with the throughbore of the string.
Body 22 also has an outer surface 27 profiled to provide a number
of functions.
[0068] Between the inner 25 and outer 27 surfaces of the body 22 is
arranged a first fluid passageway 31. First fluid passageway 31
extends from a first port 32 on the inner surface 25 to a second
port 34 on the outer surface 27. A second fluid passageway 36 is
also arranged through the body 22 to provide a conduit between a
third port 38 on the outer surface 27 and a fourth port 40, also
arranged on the outer surface 27. To achieve the second fluid
passageway 36 travelling between two points, ports 38,40 on the
outer surface 27, two conduits 42,44 are drilled into the body 22
from each port 38,40 respectively. The conduits are angled to meet
at a point 46 in the body 22 where the direction of the second
fluid passageway 36 turns. The second 34, third 38 and fourth 40
ports are spaced longitudinally along the outer surface 27 from an
upper end 23 to a lower end 21.
[0069] Towards the upper end 23 there is a stop 48 being a ring
located around the body 22 and attached thereto. At the upper end
50 of the stop 48, the face 52 is sloped while the opposing face
has two abutting surfaces 54,56. These surfaces 54,56 are
perpendicular to the longitudinal, central axis of the throughbore
24. Abutting the first surface 54 is lower end 58 of an outer
sleeve 60. Outer sleeve 60 is arranged around the body 22,
extending over the ports 34,38,40 to the chamber 16. In an
embodiment, the outer sleeve 60 includes a fastening 62 to hold a
morphable sleeve 64 of a packer to the body 22 with the chamber 16
being located between the morphable sleeve 64 and an outer surface
29 of the outer sleeve 60.
[0070] The outer sleeve 60 has a profiled inner surface 66. On the
surface 66 is an upwardly facing abutting surface 68 arranged
between the third 38 and fourth 40 ports. This abutting surface 68
of the outer sleeve 60 together with the downwardly facing abutting
surface 56 of the stop 48, the outer surface 26 of the body 22 and
the inner surface 66 of the outer sleeve 60 define a housing 70.
The second 34 and third 38 ports access the housing 70. Located in
the housing 70 is a piston 72. In the embodiment of FIG. 2(a), the
piston 72 is a sleeve located around the body 14. Piston 72 has a
length which is shorter than the distance between the abutting
surfaces 56,68 of the housing 70, so that the piston 72 can move
longitudinally with respect to the body 14. A shear pin 74,
provides retaining means to initially hold the piston 72 in a
position wherein its lower end face 76 abuts the surface 68. The
shear pin 74 is located between the piston 72 and the outer sleeve
60. This arrangement of the piston 72 at the lower end of the
housing 70 and retained by the shear pin 74, is referred to as the
first configuration.
[0071] The lower end 78 of the piston 72 is narrower than an upper
end 80 and the housing 70 is sized at its lower end 82, to provide
a sliding fit to the piston 72. The lower end 82 of the housing 70
extends from the downward side of the second port 34 to the
abutting surface 68. A seal 84 is arranged between the inner
surface 86 of the piston 72 and the outer surface 27 of the body
22. A seal 88 is also arranged between the outer surface 90 of the
piston 72 and the inner surface 66 of the outer sleeve 60. Seals
84,88 are located so as to isolate the lower 78 and upper 80 ends
of the piston 72 in the housing 70.
[0072] The piston 72 has two apertures 92,94 through the lower end
78. The apertures 92,94 are spaced apart longitudinally and
substantially align with the second 34 and third 38 ports when the
assembly 10 is in the first configuration. At the second port 34, a
recess 96 is provided in the body 22 so that fluid can flow from
the passageway 30 into the aperture 92 when the aperture 92 is
located over the recess 96. As the outer surface 90 of the piston
72 runs against the inner surface 66 of the outer sleeve 60, a
channel 98 is provided longitudinally in the outer surface 90 of
the piston 72. Channel 98 provides a flow path connecting the first
aperture 92 with the second aperture 94 and extending to the lower
end face 78 of the piston 72.
[0073] Seals 81,83 are arranged on the outer surface 26 of the body
14 at either side of the third port 38. Each seal 81,83 is
positioned circumferentially around the body 22 to prevent the flow
of fluid between the inner surface 86 of the piston 72 and the
outer surface 26 of the body 22 along the lower end 82 of the
housing 70.
[0074] At the upper end 80 of the piston 72 there is arranged a
snap-ring 85 located in a recess on the inner surface 86. A recess
87 is provided on the outer surface 26 of body 14 at the upper end
108 of the housing 70 into which the snap-ring 85 can locate when
the piston 72 moves to the lower end 89 of the housing 70. Recess
87 has a depth such that the snap-ring 85 will locate partially
therein to lock the piston 72 to the body 22.
[0075] At the fourth port 40, the inner surface 66 of the outer
sleeve 60 and the outer surface 27 of the body 22 are profiled to
provide a fluid flow passageway 91 from the fourth port 40 to the
chamber 16. The passageway 91 separates the fill mechanism 12 from
the chamber 16 by longitudinally spacing the fill mechanism 12 from
the chamber 16.
[0076] While a single flow path between the throughbore 24 and the
chamber 16 has been described, it will be appreciated that any
number of flow paths may be incorporated in the mechanism 12.
Multiple ports 32 could be arranged circumferentially through the
body 22, with a sleeve or multiple individual pistons 72 arranged
at the exit port 34. Any number of channels 98 could be arranged
around the sleeve with an end gully provided to connect them all
around the outer surface 90 of the piston 72. Equally, multiple
passageways 36 could be provided and a series of parallel arranged
channels 91 on the outer surface 26 of the body 14 could direct
fluid through multiple ports into the chamber 16.
[0077] In use, the first fill mechanism 12 is arranged on a string
as shown in FIG. 1. The mechanism 12 is in the first configuration,
shown in FIG. 2(a). Piston 72 is arranged as a sleeve over the tool
body 22 and located against the lower face 68 of the housing 70.
Stop 48 is positioned on and fixed to the body 22. Outer sleeve 60
is then placed over the body 22 to form the housing 70 of the fill
mechanism 12. Alignment of the shear screw 74 will align the ports
34,38 with the apertures 92,94.
[0078] The mechanism 12 is then run-in the well in the first
configuration. A rupture disk may be located at the first port 32
to prevent any flow of fluid into the mechanism 12 until desired.
When the chamber 16 requires to be filled, fluid pressure at the
first port 32 is increased. This increase in fluid pressure may be
by increased pumping through the string or may be by running a
setting tool to the location of the port 32 and delivering
pressurised fluid to the port 32 via the tool.
[0079] Fluid flow into port 32 from the throughbore 24 will pass
through passageway 30, exit at port 34 into recess 96 and enter
aperture 92 in the piston 72. From the aperture 92 fluid will flow
down the channel 98 to enter the third port 38 via aperture 94.
Piston 72 is held in place by shear pin 74 so the piston 72 will
not move. The presence of seals 84 and 88 ensures the fluid is
therefore directed to the fourth port 40, through the second fluid
passageway 36.
[0080] At the fourth port 40 there is an uninterrupted flow path
through the passageway 110 into the chamber 16. The chamber 16 will
therefore be filled with pressurised fluid from the throughbore 24.
The chamber 16 will continue to fill until the pressure in the
chamber 16 matches the shear rating on the shear pin 74. At this
point, fluid acting on the between the seals 84,88 will be
sufficient to shear the pin 74 and the piston 72 will move upwards
in the housing 70.
[0081] Passageway 93 is shown in FIG. 2(b) of the drawings.
Passageway 93 joins the second port 34 to the aperture 92 and will
increase in size as the piston 72 is moved in the housing 70. This
flow of fluid through the aperture 92 will travel through channel
98 and fill a lower housing chamber created by the separation of
surfaces 76 and 68. As chamber 16 fills, pressure on surface 76
will continue to move the piston 72 through the housing 70 towards
the upper end 22. During movement the seals 84,88 on the piston
remain sealed to the surfaces 27,66 of the outer sleeve 60 and body
14, respectively, to keep fluid within the lower end 82 of the
housing 70.
[0082] As piston 72 moves upwards aperture 94 will move away from
port 38 and the inner surface 86 of the piston 72 will slide over
the port 38. Aperture 94 will pass over the seal 100 and
consequently the passageway 36 is blocked, being sealed at the port
38 by the piston 72 acting as a sliding sleeve valve in the
longitudinal direction, co-linear with the central axis. Debris is
kept from the port 38 by the action of the sealing surface 78 being
drawn across the seals 81,83. The sliding sleeve, piston 72, is
contained within a housing 70 located between the inner surface 24
of the body 22 and the outer surface 97 of the outer sleeve 60.
Sealing the port 38 contains fluid at a fixed pressure within the
chamber 16.
[0083] To hold the piston 72 in the sealed position, the piston 72
is moved until the snap-ring 85 is free to move inwardly into the
recess 87 on the body 14. Snap-ring 85 bridges between the body 14
and the piston 72 to prevent relative longitudinal movement
therebetween. A stop 99 is also present in the housing to limit
upward movement of the piston 72. In this position, as illustrated
in FIG. 2(b), the mechanism 12 is considered as locked, being in a
second configuration.
[0084] The seal at port 38 can be maintained for the life of the
well fluid exiting the chamber 16 and maintain the pressure within
the chamber 16. The first fill mechanism 12 is as described in
WO2015/022552 which is incorporated herein by reference.
[0085] Returning to FIG. 1, it can be seen that the chamber 16 is
also accessed via a further port 11. Port 11 connects to a delivery
conduit 152 from the second fill mechanism 14 located towards the
end 23 of the tool 18. A check valve 13 is located on the conduit
152 to prevent fluid travelling from the chamber 16 to the second
fill mechanism 14. The second fill mechanism 14 comprises a
pressure intensifier.
[0086] In the preferred embodiment the second fill mechanism 14 is
as illustrated in FIGS. 3(a) and 3(b). The pressure intensifier
comprises an outer cylindrical body 112 and an inner tubular body
22 in the form of a mandrel 122. The mandrel 122 is the tubular
body 22 of the first fill mechanism 12. The outer cylindrical body
112 is provided with a first end 114, a second end 116 with a
central length 117 therebetween formed by an outer cylindrical wall
118.
[0087] Cylindrical body 112 is of metal construction and is a
substantially hollow tubular having a cylindrical wall 118 with an
inner surface 119 defining a bore 120 therethrough. Within bore 120
is arranged co-axially a cylindrical mandrel 122, also of metal
construction, having an outer surface 123 and an inner surface 124
that defines an inner bore 126. The mandrel 122 forms the tubular
body 22 and is further provided with a first end 130 having a
suitable fitting as are known in the art for connecting the
mechanism 14 into a string not shown for running the downhole
apparatus 10 into a wellbore. Suitable strings may be coiled,
tubing, drill pipe, liner and the like. The mandrel 122 is thus
fixed on a string. The second end 132 forms the tubular body 22 of
the first fill mechanism 12. The inner bore 126 aligns with and
forms the throughbore 24 of the downhole apparatus 10.
[0088] Arranged within bore 120 at first end 114 of the cylindrical
body 112 is a locking mechanism 134 which in this case comprises
shear pins that extend through openings 133 in the cylindrical wall
118 and are received in recesses 135 formed in the first end 130 of
mandrel 122. The shear pins 134 secure the cylindrical body 118 and
mandrel 122 relative to one another. The shear pins can be
removable inserted into the recesses 135 through openings 133 such
that the pins 134 used can be provided at different strengths so
that a suitable pin is used depending on the environment in which
the apparatus 10 is deployed and the level of fluid pressure which
will pass through the bore 126 in general operation as well as the
level of fluid pressure required to actuate the pressure
intensifier 14.
[0089] A pressure development mechanism 137, which may be
considered as a low pressure housing, is formed from the first end
114 along the central length 117 of the cylindrical body 112 with
pistons 140 provided at intervals along the central length 117. A
pressure application mechanism 136 is formed at the second end 132
of the mandrel 122. The pressure application mechanism 136 may be
considered as a high pressure housing.
[0090] In the pressure development mechanism 137, the central
mandrel 122 continues co-axially through cylindrical body 112. The
cylindrical body 112 is provided along its central portion 117 with
actuating pistons 140. In the embodiment show, the mechanism 137 is
provided with two actuating pistons 140a, b and a high pressure
piston 140c with each piston 140a, b, c associated with a segment
of mandrel 122a-c respectively. The pistons 140a, b, c are spaced
apart along, and project perpendicularly inwards from the
cylindrical wall 118. Each piston 140a, b, c is substantially
annular and extends across bore 120 such that a movable seal is
formed between internal piston surface 142 and recessed portion 125
of outer surface 123 of mandrel 122.
[0091] The pressure development mechanism 137 further includes
annular stop mechanisms 144 which are spaced equidistantly apart
and project from the outer surface 123 of mandrel 122. In the
embodiment shown, two annular stop mechanisms 144a, b are provided
projecting from the from the outer surface 123 of mandrel portions
122a and 122b respectively such that a movable seal is formed
between inner surface 119 of the cylindrical body 112 and the
projected surfaces 145a, 145b of the mandrel stops 144a, 144b. The
third annular stop mechanism 144c is formed by the active surface
145c of the pressure application mechanism 136.
[0092] The mandrel 122 is further provided with ports 146 spaced
apart along the length of the mandrel. In this case, three ports
146a, 146b and 146c are provided. The ports 146a,b,c enable fluid
communication between the mandrel bore 126 and voids 148a, 148b,
148c defined between an active surface 149 of pistons 140, a void
defining surface 150 and recess surface 125 of outer surface 123 of
the mandrel 122.
[0093] Between the leading face 143a, b, c of the pistons 140a, b,
c, stop mechanisms 144a, b, c, recessed outer surface 125 of
mandrel 122 and inner surface 119 of cylindrical body 122, there
are further defined annular voids 120a, 120b, 120c. Each of annular
voids 120a, 120b is provided with a port 127 which extends through
wall 118 of body 112.
[0094] In the pressure application mechanism 136 the mandrel 122 is
provided with a segment 122d having a cylindrical wall 121d that
overlaps cylindrical wall 121c of segment 122c in a manner which
causes it to extend annularly across bore section 120c such that a
movable seal is formed between surface 123d and 119d. The thickness
of the mandrel wall 123 where segments 122c and 122d overlap
provides additional resilience to pressure created by the pressure
intensifier. A delivery conduit 152 is defined longitudinally
through cylindrical wall 121d of pressure application mechanism 136
such that it is parallel to bore 126. A delivery port 154 allows
fluid communication between void 120c and delivery conduit 152. The
delivery conduit 152 is operable then to provide fluid
communication between annular void 120c and a desired the chamber
16. The diameter of the fluid delivery conduit 152 is less than the
diameter or annular void 120c which, in turn, is less than the
diameter of annular voids 120a and 120b. The annular void 120c is
provided with application fluid 156, which may be any suitable
fluid including, for example, clean water.
[0095] The second fill mechanism 14 is operable to have two states.
In the first state, the components of the second fill mechanism 14
are arranged in a first position as is shown in the embodiment
illustrated in FIG. 1. The second fill mechanism 14 is in a first
state prior to actuation of the mechanism 136 to apply fluid under
pressure to the chamber 16.
[0096] In the first state, the first end 114 of the body 112 is
arranged such that it extends longitudinally away from first end
130 of mandrel 122 and is secured in position by retaining
mechanism 134. End 130 is attached to a sting providing a
continuous central bore 126 through the pressure intensifier of the
second fill mechanism 14. The pressure application mechanism 136
extends longitudinally beyond the second end 16 of cylindrical body
112.
[0097] The inner surface 119, outer surface 124, actuating piston
140a and mandrel void defining surface 150a co-operate in the first
state so as to form a chamber 148a. The first actuating piston 140a
is arranged so that it is spaced remotely along the bore 120 from
stop 144a. The actuating piston 140a, inner surface 119, outer
surface 125 and stop 144a co-operate in the first state to form a
chamber 120a.
[0098] Similarly, the actuating piston 140b is arranged spaced
remotely along the bore 120 from stop 144b. The actuating piston
140b, void defining surface 150b, outer surface 125 and stop 144a
co-operate in the first state to form an enclosure 148b. The
actuating piston 140b, inner surface 119, outer surface 125 and
stop 144b co-operate in the first state to form an enclosure
120b.
[0099] High pressure piston 140c is arranged mounted projecting
inwardly from cylinder 112 such that in a first state it is closely
adjacent to stop 144b and defines enclosure 148c. The high pressure
piston 140c, outer surface 125, void defining surface 150c and
fluid facing face 154 of bore stop 144c co-operate in the first
state to form a sealed enclosure 120c which is filled with
operating fluid 156.
[0100] Each co-operating mandrel and cylindrical body or piston
surface is provided with a resilient seal ring 160 such as a rubber
or elastomeric o-ring or similar, that provides a resilient seal
between the adjacent surfaces. The seal rings 160 allow lateral
movement between the mandrel surfaces and the inner wall and piston
surfaces whilst preventing the passage of fluid therebetween.
[0101] Each piston 140 may be integrally formed with mandrel 122 or
is attached to the cylindrical body segments by a screw mechanism
such that the pistons 140 act as joining mechanisms between
adjacent cylindrical body segments. This enables the cylindrical
body and piston arrangement to be constructed, and built up from
the bottom of, a mandrel secured in position.
[0102] Upon actuation, the moveable components of intensifier,
namely, the components of the cylindrical body 112 and piston
arrangement, through the process of receiving and applying fluid
under pressure, move to a second state. The arrangement of the
components in the second state is shown in FIG. 3(b).
[0103] In use, the second fill mechanism is connected on a string
at end 130 and the first fill mechanism 12 with the chamber 16 is
connected at end 136 of the mandrel 122. As both the first and the
second fill mechanisms 12,14 are actuated by fluid pressure through
the throughbore 24, a determination is made as to the maximum fluid
pressure which is likely to be applied through the string when the
apparatus 10 is in the wellbore and activation is not required.
This is the pressure rating set for the rupture disc of the first
fill mechanism 12. The shear pins 134 are then selected to shear at
a greater pressure than the maximum fluid pressure calculated to
actuate the first fill mechanism 12. The shear pins 134 can then be
arranged in the locking mechanism. The selection of the shear pin
rating can be done in the field.
[0104] The apparatus 10 is then run in the wellbore whereupon fluid
in the bore 126 enters ports 146 to fill the enclosures 148.
Additional fluid outside the string will fill the enclosures 120.
The second fill mechanism 14 will not activate and no components
will move until the pressure of fluid entering the ports 146 is
sufficient to shear the pins 134. The hydraulic fluid pressure
entering the ports 146 acts on the active surface 150 of the
pistons 140 and when this is greater than the shear pressure on the
pins 134, these will shear releasing the cylindrical body 112 and
piston arrangement 140. Consequently the voids 148 will increase in
size as the pistons 140 move longitudinally downwards over the
mandrel 122.
[0105] As the pistons 140 move downwards, enclosures 120 will
reduce in size as the volume of each void decreases. Fluid in the
enclosures 120 will be forced out of the mechanism 14 through ports
127. Enclosure 120c does not include a port 127 and instead, the
exit of fluid is through the delivery conduit 152. The fluid is the
operating fluid sealed in the enclosure 120c before activation.
High pressure piston 144c thus acts upon the application fluid 156
and forces the fluid 156 into the delivery conduit 152, passing
through the check valve 13 and adding to the fluid under pressure
in the chamber 16.
[0106] In FIG. 3(b), the arrangement of the components of the
second fill mechanism 14 are shown in a second state, subsequent to
activation according to an embodiment of the invention. In this
embodiment, outer cylindrical body 112 has been driven forward as
has pistons 140a,b such so that they now abut against stops 144a,b
respectively and high pressure piston 144c has been driven forward
to abut against wall end stop 154. The force created by hydraulic
pressure acting upon pistons 140a,c cumulatively acts upon
application piston 144c such that the fluid 156 is driven through
delivery conduit 152 with a much greater force than that in the
throughbore 24.
[0107] The cumulative pressure against pistons 140a,b creates a
total force applied to the operating fluid 156 by the movement of
piston 144c which is the sum of force from all the pistons 140a,be.
The increased thickness of overlapped walls 122c, 122d, 118c
enables the force of pressure applied through to the conduit 152 to
be directed to the chamber without damaging or causing deformation
of the second fill mechanism 14.
[0108] The number of pressure development segments used in the
pressure intensifier can be varied depending upon the level of
pressure required for a particular use of the intensifier; the more
pressure development segments in the form of pistons 140, outer
cylindrical segments 112 and stops 148 included in the intensifier,
the more pressure will can be applied from the second fill
mechanism 14. Fewer segments and pistons will result in a lower
pressure being applied by the second fill mechanism 14.
[0109] The second fill mechanism 14 is a pressure intensifier.
While one embodiment of a pressure intensifier has been described,
it will be appreciated by those skilled in the art that other
pressure intensifiers exist which could be used, for example, the
pressure intensifier described in WO2016/051169 which is
incorporated herein by reference. Additionally, pressure
intensifiers which contain motors which may be electrically driven
can also be used.
[0110] Returning to FIG. 1, it can be seen that the first fill
mechanism 12 is arranged at the chamber 16. In this embodiment, the
tool 18 is a packer and a morphable sleeve 64 is fastened to the
body 22 with the chamber 16 being located between the morphable
sleeve 64 and the outer surface 29 of the outer sleeve 60. The
morphable sleeve 64 is located around a portion of the tubular body
22 with the body 22 located coaxially within the morphable sleeve
64. Morphable sleeve 64 is a steel cylinder being formed from
typically 316L or Alloy 28 grade steel but could be any other
suitable grade of steel or any other metal material or any other
suitable material which undergoes elastic and plastic deformation.
The morphable sleeve 64 is appreciably thin-walled of lower gauge
than the tubing body 22 and is preferably formed from a softer
and/or more ductile material than that used for the tool body 22.
The morphable sleeve 64 may be provided with a non-uniform outer
surface such as ribbed, grooved or other keyed surface in order to
increase the effectiveness of the annular seal created by the
morphable sleeve 64 when secured within another casing section or
borehole.
[0111] An elastomer or other deformable material may be bonded to
the outer surface of the morphable sleeve 64; this may be as a
single coating but is preferably a multiple of bands with gaps
therebetween.
[0112] Thus the tool 18 can be considered as a packer with integral
fill and intensifier features 10.
[0113] In use, tool 18 is constructed with the sleeve 64 against
the outer surface 29 of the tubular body 22 providing a chamber 16
therebetween which will have an initial or first chamber pressure
and a first chamber volume. The packer will be uninflated. The
rupture disc of the first fill mechanism 12 is set at a value at
which it is desired for the packer 18 to start inflating in the
wellbore 20. Shear pin 74 is set to a value at which the packer 18
will be partially set and will typically reflect a pressure value
which is easily achievable by pumping fluid from surface. In the
second fill mechanism 14, the shear pins 134 are set at a higher
pressure rating than shear pin 74. Shear pins 134 can
advantageously be set in the field so that adjustment can be made
depending on the pressure of fluids which may have to be pumped
down the throughbore 24. The packer 18 then run to a desired
location in the wellbore 20. As long as pressure in the throughbore
24 is kept below the disc rupture pressure, the packer 18 will
remain uninflated. This is shown in FIG. 4(a).
[0114] When the packer requires to be inflated or set, fluid pumped
through the throughbore 24 would be increased to a low pressure
value sufficient to rupture the disc in the first fluid mechanism
12. As described hereinbefore, this will fill the chamber 16. If,
for example, we pressure up to a low pressure, say 4,000 psi, this
will start the setting process on the packer 18. Fluid introduced
to the chamber 16 will increase the pressure in the chamber 16
until it is sufficient to elastically expand the packer sleeve 64
and thus move it radially outwards across the annulus 28 and
contact the wellbore wall 30. Once the packer 18 is mainly set with
the 4,000 psi, we pressure up to 4,500 psi which will shear pins 74
in the first fill mechanism 12 and the piston 72 will close and
lock the 4,000 psi in the packer 18. Consequently the chamber 16 is
now at a second chamber pressure, 4,000 psi, and a second chamber
volume, representing the mainly set packer 18. Thus the second
chamber pressure and volume is less than the first chamber pressure
and volume. This is shown in FIG. 4(b).
[0115] Then we pressure 5,000 psi, which is the rating of the shear
pins 134 of the second fill mechanism 14. This will activate the
pressure intensifier as described herein before, the mandrel 122
will stroke down with the piston 144 pushing the application fluid
156 past the check valve 13 and into the chamber 16. Application
fluid 156 at a multiple of the 5,000 psi pressure is delivered to
the chamber 16. The volume of application fluid 156 is relatively
small e.g. less than one litre, so the mainly set packer 18 is
fully set by the great increase in pressure in the chamber 16.
Typically, this pressure increase will be sufficient to plastically
deform the packer sleeve 64 so it permanently sets against the wall
of the wellbore 20 or another tubular in which the packer 18 is
located. The check valve 13 holds this new pressure inside the
packer 18. The chamber 16 will now be at a third chamber pressure
and volume, with the volume being only slightly greater than or
equal to the second chamber volume, while the pressure is
significantly greater than the second chamber pressure, say 10,000
psi depending on the number and surface area of pistons in the
second fill mechanism 14. This allows you to set the packer 18 with
5,000 psi but get effectively 10,000 psi into the packer 18. Those
skilled in the art will appreciate that these pressures could be
adjusted based on what is needed for the well, it could be 3,000
psi with a 3x multiple or whatever is required. This is shown in
FIG. 4(c). In particular, as the volume of application fluid 156
can be kept small the second fill mechanism can be kept appreciable
small. Thus by providing a two stage fill process, the packer can
be inflated to a high pressure without requiring a large void of
fluid to be stored downhole.
[0116] The embodiment described refers to a packer, but it will be
appreciated by those skilled in the art that any chamber can be
filled to a high pressure downhole using the apparatus and method
of the present invention. For example, the chamber may be a void at
a piston face and the piston is actuated by the delivery of high
pressure fluid.
[0117] The principle advantage of the present invention is that it
provides a method and apparatus for delivering fluid at a first
pressure and then at an increased pressure to a chamber located in
a wellbore which does not require pumping of fluid at the increased
pressure from surface.
[0118] The further advantage of the present invention is that it
provides a method and apparatus for delivering fluid to a chamber
located in a wellbore where the delivery is staged and the fluid
pressure is cumulatively increased at each stage.
[0119] A further advantage of at least one embodiment of the
present invention is that is that it provides a method and
apparatus for delivering fluid at a first pressure to mainly set
and then at an increased pressure to fully set an inflatable packer
located in a wellbore which does not require a fluid reservoir at
the increased pressure to entirely inflate the packer to be stored
in the apparatus.
[0120] It will be appreciated by those skilled in the art that
modifications may be made to the invention herein described without
departing from the scope thereof. For example, in the second fill
mechanism the ports are shown in the above embodiments as small
round holes through the mandrel. However, the instead of a single
hole, each port may comprise a plurality of holes, or the port may
be shaped as a slit, a slot or a plurality of slots formed around
the circumference of the mandrel. The pistons and stops may also
have different shapes and configurations. Additionally, the fill
mechanisms may be arranged at one or both sides of the chamber. The
fill mechanisms may be arranged to fill more than one chamber.
* * * * *