Note: Descriptions are shown in the official language in which they were submitted.
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INFLATABI,E PACKER ASSEMBLY WIT~ CONTROL VALVE
This application is a divisional of our co-pending
Canadian Patent Application Serial No. 337,967, filed
October 18, 1979.
This invention relates generally to an inflatable
packer assembly for use with a casing or other tubular
member of a well.
An inflatable packer i5 a downhole tool which can be
inflated with well fluid to seal off the annular space
between, for example, the casing and the wellbore. It may
also be used inside a casing.
Inflatable packers may be used in a well for a variety
of reasons. They can be used to support a column of cement
above a lost circulation zone. They can be used to isolate
producing zones from cementing operations. Also, they may
be used to isolate production and lost circulation zones
for gravel pack operations.
Typical prior art control valves for inflatable packers
have included both spring loacled check valves, and various
forms of sliding sleeve valves, for controlling the flow of
well fluid to the inflatable element to inflate the same.
Examples of spring loaded check valves are disclosed in
U. S. Patents Nos. 3,437,142 to Conover, No. 3,085,628 to
Malone, and No. 2,177,601 to Smith. Examples of sliding
sleeve valves are disclosed in U. S. Patent No. 3,524,503
to Baker and No. 3,053,322 to Kline.
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The present invention provides an inflatable packer
assembly, comprising: a cylindrical mandrel; a packer
disposed about an outer cylindrical surface of said
mandrel, said packer including an inflatable element; and
valve means, connected to said packer, for directing fluid
under pressure to said packer to inflate said element,
said valve means including a cylindrical valve body having
first and second ends with a cylindrical inner surface
connecting said first and second ends, said cylindrical
outer surface of said mandrel being closely received
within said cylindrical inner surface of said valve
means and said cylindrical outer surface of said mandrel
extending past each of said first and second ends of
said valvè means.
FIG. 1 is a schematic partly sectional elevation
illustration of the inflatable packer assembly with
control valve of the present invention in place within
an oil well borehole.
FIGS. 2A-2C comprise an enlarged sectional elevation
view of the inflatable packer assembly with control valve
of FIG. 1.
FIG. 3 is an isometric view of the control valve with
a portion
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of the wall thereof removed to show the piston bores and inter-
connecting ports.
FIG. 4 is a schematic representation of the piston bores and
ports of the valve of FIG. 3.
S FIG. 5 is an enlarged view of the counterbore 96 of second
bore 56 of the valve of FIG. 3.
FIG. 6 is a sectional elevation view of an alternative embodi-
ment of the control valve assembly of the present invention.
FIG. 7 is a partial sectional view taken along line 7-7 of
~O FIG. 6.
FIG. 8 is a sectional view ta]~en along line 8-8 of FIG. 7.
Referring now to the drawings, and particularly to FIG. 1, the
inflatable packer assembly of the present invention is shown and
~5 generally designated by the numeral 10. The inflatable packer
assembly 10, which may more generally be referred to as a downhole
tool, is generally connected as an integral part of a casing string
12, which may generally be referred to as a tubular member. The
casing string 12 is disposed in a borehole or well hole 14 of an
'O oil well so that there is an annular cavity or space 16 between
casing string 12 and well hole 14. It will be understood by those
skilled in the art, that the present invention could be equally
well applied to a downhole tool connected to a drill string located
within a well hole defined by an inner surface of a well casing.
'5 The inflatable packer assembly 10 includes a cylindrical mandrel
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1~3 f'~70
18 having an inflatable element which may be referred to as a
bladder means or packer 20 connected to the mandrel 18 for sealing
said annular cavity 16. The bladder means 20 and the mandrel 18
define an annular fluid-filled space 22 therebetween when said
bladder means 20 is inflated to seal said cavity 16.
A valve means generally designated by the numeral 24 includes
an inlet 26 communicating with an interior of tubular member 12
through an interior 28 of said mandrel 18, and an outlet 30 com-
municating said annular space 22. Lhe valve means 24 communicates
said interior 28 of said mandrel 18 with said annular space 22
when a fluid pressure differential between said interior 28 of
said mandrel 18 and said cavity 16 adjacent a lower end 54 of said
valve means 24 reaches a first predetermined level, so that fluid
from said interior 28 flows into said annular space 22 to inflate
said bladder means 20 as illustrated in FIG. 1.
The valve means 24 also includes a means for isolating said
interior 28 from said annular space 22 when said pressure differ-
ential reaches a second level higher than said first level, while
preventing any loss of fluid from said annular space 22 as said
interior 28 is being isolated therefrom.
Referring now to FIGS. 2A-2C, the inflatable packer assembly
10 includes an upper body 32 threadedly connected to an upper end
34 of mandrel 18 for connecting mandrel 18 to the casing string 12.
The bladder means 20 is connected at its upper and lower ends
to upper and lower packer shoes 36 and 38, respectively.
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Upper packer shoe 36 sealingly engages an outer cylindrical
surrace 40 of mandrel 18 with a plurality of O-rings ~2. W!1en blad-
der means 20 is in the uninflated position shown in FIG. 2 the
upper packer shoe 36 abuts an upper bac~up ring 44. Upper backup
ring 44 is welded to outer cylindrical surface 40 of mandrel 18
as indicated at 46.
Valve means 24 includes a cylindrical valve body 48 concen-
trically disposed about outer surface 40 of mandrel 18. The cylin-
drical valve body 48 includes the inlet 26 which is permanently
aligned with a hole 50 disposed through a wall of said mandrel 18
and communicating with said interior 28 of mandrel 18.
Valve body 24 also includes the outlet 30 for directing fluid
from the interior 28 to the annular fluid-filled space 22 of bladder
means 20. Bladder means 20 may also be referred to as a component
of the downhole tool which is ~o be actuated by said fluid from the
interior of mandrel 18.
As is best seen in FIGS. 3 and 4, the valve body 48 further
includes a first axial bore 52 connecting said inlet 26 with an
end surface 54 of said cylindrical valve body 48. Valve body 4%
; 70 also includes a second axial bore 56 communicating with said end
54 of valve body 48. End surface 54 communicates with the annular
space 16 about outer cylindrical surface 40 of mandrel 18.
A first port means, generally designated by the numeral 58,
interconnects said first and second bores 52 and 56. First port
means 58 comprises a third axial bore 60 whlch is intersected by
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first and second crossbores 62 and 64. Crossbores 62 and 64 also
intersect first and second axial bores 52 and 56.
A second port means, generally indicated by the numeral 66
interconnects second bore 56 with outlet 30. Second port means 66
S comprises a fourth axial bore 68 connecting first end 54 of valve
body 24 with outlet 30. Second port means 66 further comprises a
third crossbore 70 intersecting second and fourth axial bores 56
and 68.
Those ends of third and fourth a~ial bores 60 and 68, and of
first, second and third crossbores 62, 64 and 70, which communicate
with first end 54 of valve body 48 or with radially outer surface
72 of valve body 48 are sealed after being drilled, with pipe plugs
74 as shown in FIG; 4.
: ~ first or primary piston 76 is slidably disposed in first
. L5 bore 52. First piston 76 has first and second ends 78 and 80, re-
spectively, which are in fluid communication with said inlet 26
and said first end 54 of valve body 48, respectively.
First piston 76 is movable between a first position, illustrated
in FIG. 4, blocking said first port means 58 and a second position
~0 (displaced to the right from the position shown in FIG. 4 so as to
abut lower backup ring 134) allowi.ng fluid communication between
said inlet 26 and said first port means 53. When first piston 76
is in said second position, the first end 78 is displaced to the
right past first crossbore 62, so that. inlet 26 is communicated
'5 with first crossbore 62.
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Referring to FIG. 2C the first piston 76 is thereshown in
its first position. First piston or primary piston 76 is connected
to valve body 48 by a first shear pin 82. Shear pin 82 may be
referred to as a means for holding first plston 76 in said first
position until a fluid pressure differential between interior 28
of mandrel 18 and said first end 54 of valve body 48, _e. annular
space 16, reaches a first level, and for releasing first piston 76
so that it may be moved to said second position by said pressure
differential when said differential reaches said first level.
Pirst piston 76 includes a reduced diameter portion 83, be-
tween first and second ends 78 and 80 thereof. It is very diffi-
cult to manufacture a long bore of relatively small diameter, such
as first bore 52, which is absolutely straight. The bore 52 gen-
erally will have some very slight curve or other irregularity from
the desired straight line ofbore. The reduced diameter portion 83
of first piston 76 gives piston 76 sufficient fle~ibility so that
it may bend slightly to accommodate such irresularities in bore 52
when piston 76 is moving between its said first and second positions
within bore 52. This provides an advantage over a constant dia-
meter piston which would have more of a tendency to become stuckwithin an irregular bore.
A second piston 84 is slidably disposed in second bore 56.
Second piston 84 includes first and second ends 86 and 88, respec-
tively. The first end 86 is in fluid communication with first port
means 58 and second end 88 is in fluid communication with said first
113~870
end 54 of valve body 48 which communicates with annular space 16.
Second plston 84 is movable between a first position, illus-
trated in FIG. 4, allowing fluid communication between said first
and second port means 58 and 66, respectively, and a second posi-
tion (displaced to the right from that shown in FIG. 4 so as toblock third crossbore 70) blocking said second port means 66.
Second piston 84 includes a middle portion 90 of reduced dia-
meter, so that when second piston 84 is in said first position said
first and second port means 58 and 66 are communicated through said
second bore 56 around said reduced diameter middle portion 90 of
second piston 84.
Second piston 84 is connected to valve body 48, when in the
first position illustrated in FIG. 4, by a shear pin (not shown)
similar to shear pin 82. The shear pin connecting second piston
84 to valve body 48 may also be referred to as a means for holding
said second piston 84 in said first position until said fluid pres-
sure differential between said interior 28 and said first end 54
of valve body 48 reaches a second level, said second level being
higher than said first level, and for releasing said second piston
84 so that it may be moved to its said second position by said pres-
sure differential when said pressure differential reaches said second
level.
First and second pistons 76 and 84 each include a plurality of
O-rings 92 for sealing against their respective bores 5 and 56.
Second piston 84 includes an outer annular groove containing
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an expandable metal retaining ring 94. When second piston 84
is displaced to the right from the position shown in FIG. 4 to
its second position, retaining ring 94 expands and engages a coun-
terbore 96 which is concentric with second bore 56 and communicates
S with first end 54 of valve body 2a. This locks second piston 84
into said second position, and permanently and automatically iso-
lates interior 28 from the annular space 22 when the pressure
differential reaches said second level.
Referring to FIG. 5 the details of construction of counter-
bore 96 are illustrated. A shoulder 98 between second bore 56
and counterbore 96 is cut at an angle 100 to a plane normal to the
longitudinal axis of bore 56. The angle 100 is preferrably approxi-
mately 20~. Shouldér 98 is joined to counterbore 96 by a tapered
surface 102 which is tapered at an angle 104 to the longitudinal
axis of counterbore 56. The angle 104 is preferrably approximately
15. This construction of the counterbore 96 is preferrable for
aiding expandable retaining ring 94 in locJcing itself in counter-
bore 96.
As shown in FIG. 2C a removable knock-out plug 106 is engaged
20 with and blocks hole 50 in the wall of mandrel 18. Xnock-out plug
106 includes a tubular portion 108 having external threads 110
engaging said hole 50. Knock-out plug 106 also includes an exten-
sion 112 projecting radially into said interior 28 of mandrel 18.
Knock-out plug 106 is constructed so that extension 112 may be
broken or sheared off by a force from above.
_g_
1~7~70
The extension 112 is generally sheared off by pumping a
cement plug down the interior of casiny 12 and mandrel 18 or by
running some other tool on a drill strlng down the casing 12 so
as to stri~e knock-out plug 106 and shear off extension 112.
The knock-out plug 106 is so constructed that when extension
112 is sheared off it shears at a point within hole 50 so that
there are no sharp edges projecting into interior 28 of mandrel
18 which might cut swab cups or the like being moved through casing
12.
When extension 112 is sheared off of knock-out plug 106 this
allows fluid communication between interior 28 and the inlet 26
of valve body 48 through the tubular portion 50 of knock-out plug
106.
The valve means 24 is so constructed that it may be very easily
assembled with the mandrel 18. The valve means includes the cylin-
drical valve body 48 having the first end 54 and a second end 114.
A constant diameter cylindrical inner surface 116 of valve
body 48 innerconnects said first and second ends 54 and 114, res-
pectively. The cylindrical outer surface 40 of mandrel 18 is closely
received within said cylindrical inner surface 116 of valve body 48
and such cylindrical outer surface 40 of mandrel 18 extends past
each of said first and second ends 54 and 114 of said valve body 48.
The outlet 30 of valve means 24 includes an annular axially
extending groove 118 disposed in said second end 114 of valve body
48. Axially extended groove 118 defines radially inner and outer
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a~ially e~tending concentric tongues 120 and 122, respectively.
A portion 124 of lower annular packer shoe 38 adjacent said
second end 114 of valve body 48 is radially spaced from said outer
cylindrical surface 40 of mandrel 18 forming an annular passage
126 communicating with said annular groove 118 of said outlet 30
of said valve means 24.
The inner tongue 120 of first end 114 of valve body 48 is
welded ~o said radially outer surface 40 of mandrel 18 as indi-
cated at 128. Radially outer tongue 122 of first end 114 of valve
10 body 48 is welded to said lower annular packer shoe 38 as indicated
at 130. This construction provides the strength of full 1/4 inch
fillet welds at 128 and 130, while also providing a large flow area
by the intersection of groove 118 and annular passage 126.
~irst end 54 of valve body 48 is welded to outer cylindrical
surface 40 of mandrel 18 as indicated at 132. ~irst end 54 of valve
body 48 engages a lower backup ring 134 which itself ls welded to
mandrel 18 at 136.
An upper portion of lower backup ring 134 is radially spaced
from outer surface 40 of mandrel 18 so as to define an annular
space 138 which communicates with first end 54 of valve body 48
and with first and second bores 52 and 56. A relief bore 140 com-
municates annular space 138 with the cavity 16 between mandrel 18
and borehole 14.
The modular construction of the inflatable packer assembly 10
described above allows a variety of different weight ranges of t.~e
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packer assembly 10 to be constructed using the same packer or
bladder means 20 and the same valve means 24. All that is re-
~uired to vary the design capacity of the inflatable packer as-
sembly 10 is to vary the weight of the mandrel 18. This greatly
reduces the cost of manufactura of the inflatable packer assembly
10 as compared to~}~t~ art designs wherein the valve means was
constructed integrally with a portion of the casing or of the man-
drel.
The operation of the inflatable packer assembly 10 is as
follows. The inflatable packer assembly 10 is constructed and
assembled as illustrated in FIGS. 1 and 4 with the first and sec-
ond pistons 76 and 84 in their first positions with the shear pins
in place. The inflatable packer assembly 10 is then attached as
15 an integral part o casing 12 as illustrated in FIG. 1 and is
lowered into the borehole 14 until the packer 20 is adjacent the
location where it is desired to seal the cavity 16 between the cas-
ing 12 and the borehole 14.
To prevent premature inflation of the packer or bladder means
20 20 while running the casing 12 into the hole 14, the hole 53 and
inlet 26 are blocked by the knock-out plug 106.
Once the casing is properly positioned and it is desired to
inflate the packer 20, the extension 112 is sheared off of the
knock-out plug 106 to allow fluid from interior 28 of the mandrel
18 to enter inlet 26.
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. _
1~37~70
In a preferred embodiment of the present invention, once
the knock-out plug 106 is removed the first piston 76 will remain
in its first position until a pressure differential across that
first piston, i.e. a pressure differential between the interior
28 of mandrel 18 and the cavity 16, reaches a first predetermined
level at which the shear pin 82 is designed to shear. ~n a pre-
ferred embodiment this first level equals a differential pressure
of 1480 psi (- 150 psi for 99~ probability).
When the pressure differential reaches that first level the
shear pin 82 shears and allows first piston 84 to move to its
second position so that fluid may flow through first port means 58,
second bore 56, and second port means 66 to outlet 30. The fluid
flows through outlet 30, then through annular passage 126, and then
through the narrow annular clearance 142, between lower packer shoe
lS 38 and outer surface 40 of mandrel 18, to the annular space 22 be-
tween bladder means 20 and mandrel 18.
When the fluid under pressure from the interior 28 of mandrel
18 flows into the annular space 22 it inflates the bladder 20 from
the uninflated position shown in FIGS. 2A and 2B to the inflated
position shown in FIG. 1.
The annular space 22 will remain in fluid communication with
the interior 28 of mandrel 18 until the pressure differential be-
tween the irlterior 28 and the cavity 16 reaches a second level at
which the shear pin of second piston 84 is designed to shear and
allow the second piston 84 to move to its second permanently locked
113~;870
position. When second piston 84 is in its second position the
second port means 66 is permanently isolated from the interior 28
of mandrel 18 so that the bladder means 20 remains permanently
inflated. The second level, at which the shear pin of the second
S piston shears, is higher than said first level of said pressure
differential, and in a preferred embodiment of the present inven-
tion said second level is equal to 2000 psi (+ 200 psi for 99
probability).
An important feature of the present invention is that when
the second valve 84 moves from its first position to its second
position, to block second port means 66, there is no loss of fluid
from annular space 22. The volume of second port means 66 when
second piston 84 is in the first position of FIG. 4 is equal to
a volume of said second port means 66 when second piston 84 is in
its second position blocking port means 66. Automatic control
valves for inflatable packers of the prior art have included means
for automatically shutting off the supply of fluid to the inflat-
able packer, but those prior art control valve means have typi-
cally included a structure such as that of U. S. Patent No. 3,524,503
to Baker having a sliding piston with one end in fluid communi-
cation with the annular space 22 so that when a certain pressure
is reached within that annular space 22 the piston is moved to a
closed position. However with such prior art designs the movement
of the piston to the second closed position causes that end of the
piston in communication with the annular space 22 to be moved away
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113~B~O
therefrom so as to allow a small amount of fluid to be lost
from the annular space 22.
In the applications of the present invention where the fluid
is typically a substantially incompressible fluid such as water
or drilling mud and is under very high pressure in a deep oil
well, the loss of even a very small amount of fluid, e.g. one
cubic centimeter, can create a considerable loss of pressure with-
in the annular space 22. Since the ability of the inflated packer
20 to support a column of fluid above packer 20 within the annular
cavity 16 is directly related to the inflation pressure of the
annular packer 20, this loss of pressure within the annular space
22 directly results in a lower design capacity of the inflatable
packer.
While the embodiment of the present invention illustrated
in FIGS. 1-5 is presently preferred, an alternative embodiment
illustrated in FIGS. 6-8 has been developed which includes a
secondary piston similar to the sliding piston of ~. S. Patent
No. 3,524,503 to Baker. Although the embodi.ment of FIGS. 6-8 does
have the disadvantage discussed above OL a volume loss from an-
nular space 22 upon closing of the secondary piston, it neverthe-
less provides many other desirable features of the embcdiment of
FIGS. 1-5.
The control valve assembly of FIGS. 6-8 is generally desig-
nated by the numeral 200. FIG. 6 is a vie~ similar to FIG. 2C,
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1~3~870
showing a sectional elevation view of only the control valve
assembly.
Control valve assembly 200 includes a mandrel 202 and a
valve body 204 connected to mandrel 202. Valve body 204 includes
an inlet means 206 for communicating with an interior of tubular
member 12 through interior 208 of mandrel 202 and valve body 204.
Valve body 204 further includes an outlet means 210, see
FIG. 8, for directing fluid to the bladder means 20. ~ first bore
means 212 is disposed in valve body 204 for communicating inlet
206 with annular space 16 between tubular member 12 and well hole
14. First bore means 212 communicates with annular space 16 through
a first relief hole 214 disposed substantially radially throush a
wall of said valve body 204.
A second bore means 216 is also disposed in valve body 204
and communicates with annular space 16 through a second relief
hole 218.
A first port means 220 connects first and second bores 212
and 216. A second port means 222 connects second bore 216 and
outlet 210.
A first piston 224 is disposed in first bore 212, and in-
cludes first and second ends 226 and 228, respectively, communi-
cating with inlet 206 and annular space 16. First piston 224
is movable between a first position, illustrated in FIG. 6, bloc.~ing
first port means 220, and a second position (displaced upward with-
in bore 212) allowing fluid communication between inlet 206 and
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first port means 220.
A second piston 230 is disposed in second bore 216 and
includes first and second ends 232 and 234, respectively, com-
municating with said first port means 220 and annular space 16,
respectively, when second piston 230 is in its first position as
illustrated in FIG. 8. Second piston 230 is movable to a second
position (displaced downward within bore 216) bloc~ing second port
means 222.
Second piston 230 includes an a~ial blind bore 236 communi-
10cating with second port means 222, and a radial bore 233 communi-
cating blind bore 236 with first port means 220 when second piston
230 is in its first position. When second piston 230 is moved to
its second position, the radial bore 238 is moved out of registry
with first port means 220.
15The first end 232 of second ~iston 230, upon which the fluid
pressure within both first and second port means 220 and 222 is
applied when second piston 230 is in its first position, incl.udes
the blind end of blind bore 236 as indicated in FIG. 8. It also
includes the annular end surface 240 at the uppermost end of second
piston 230.
First and second pistons 224 and 230 are held in their first
positions by shear pins 242 and 244, respectively, which operate
similar to the manner previously described for the shear pins of
the embodiment of ~IGS. 1-5~
113~ 0
Thus, the inflatable packer assembly of the present
invention is well adapted to obtain the advantages men-
tioned as well as those inherent therein. While presently
preferred embodiments of the invention have been described
for the purpose of this disclosure, numerous changes in
the construction and arrangement of parts can be made by
those skilled in the art, which changes are encompassed
within the spirit of this invention as defined by the
appended claims.
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