Note: Descriptions are shown in the official language in which they were submitted.
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MRR041186 - 1 -
SURFACE CONTROLLED SUBSURFACE SAFETY VALVE
Backqround to the Invention
This invention relates to surface controlled
subsurface safety valves used in the oil and gas industry
and particularly including a mechanism for temporarily
locking the valves open and for remedial cycling of
the valves.
Description of Related Art
It is common practice to complete oil and gas
producing wells with systems including a subsurface
safety valve controlled from the well surface to shut off
fluid flow in the well tubing string. Generally such a
valve is controlled ln response to control fluid pressure
conducted to the va~ve frorn a remote location at the well
: ~-urface via a small diameter conduit permitting the well
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MRR041186 - 2 -
to be selectively shut in as well conditions require.
However, the present invention is not limited to use
with safety valves that respond only to fluid pressure
siynals~ The surface controller is typically equipped
to respond to emergency conditions such as fire, broken
flo~ lines, oil spills, etcO Frequently it is necessary
to conduct well servicing operations through a sub-
surface safety valve. When a safety valve malfunctions,
it may be necessary to install a second safety valve.
In any event, it may be desirable either permanently or
temporarily to lock the safety valve open. For example,
if the well servicing operation requires a wireline tool
string to extend through the subsurface safety valve, it
is preferable to use a lock open system which is not
depe~dent upon control fluid pressure from the ~ell sur-
face. When operations are being carried out through an
ouen subsurface safety valve such as pressure and
temperature testiny, it can be extremely expensive and
time-consuming for a valve to accidentally close on the
supporting wireline causing damage to the wireline and
sensing apparatus supported therefrom. Additional well
servicing procedures are required to retrieve the damaged
equipment. Subsurface safety valves including both
permanent and temporary lock open mechanlsm are disclosed
in United States Patents Nos. 3,786,865; 3,882,935;
4,344,602; 4,356,867; and 4,449,587. The present
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invention particularly relates -to a suburface safety valve
of the type concerned in United States Patents Nos.
3,786,865 and 4,449,5~7 employing a temporary lockout
arrangement for the flapper type of valve closure included
in the subsurface safety valves. These listed prior
patents can be read in conjunction with the following
disclosure in this application.
Summary of the Invention
The present invention relates primarily to tubing
retrievable flapper type safety valves having a housing
connectable with a well tubing string and a bore there-
through for communicating well fluid flow with the tubing
string, a flapper valve mounted in the housing for move-
ment between a first open position and a second closed
position, and an operator tube in the housing to shift the
flapper valve between its second position and its first
position. The operator tube normally moves in respons to a
control signal from the well surface but a shifting tool
can releasably engage the operator tube for movement'
independent of the control signal. A lockout sleeve may be
mounted in the housing in tandem with the operator tube for
movement between a first position engaging and holding the
flapper valve open and a second position of disengagement
from the flapper valve. A shifting tool is also provided
having selective locating keys and latch dogs for
releasably coupling with the
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MRR041186 - ~ -
operator tube and the lockout sleeve, respectively. An
alternative embodiment of the present invention can be
used with any type of surface controlled subsurface
safety valve to cycle the valve closure mechanism if it
is stuck or the control signal is inoperative~
It is a principal object of the present invention
to provide a subsurface safety valve for use in oil and
gas wells including a lockout sleeve for teM~orarily
holding or locking open the safety valve during well
servicing operations.
It is another object of the invention to provide a
subsurface safety valve having an operator tube and a
lockout sleeve with a shifting tool latching the operator
tube and sleeve together during movement of the sleeve to
a position in which the sleeve holds the valve closure
mechanism of the subsurface safety valve open.
It is another object of the invention to provide a
subsurface safety valve having a lockout sleeve which has
a smooth, uni~orm inside diameter to minimize the possib-
ility of other well tools accidentially shifting thelockout sleeve.
It is another object of the invention to provide a
subsurface safety valve including a ternporary lockout sleeve
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MRR0~1186 - 5 -
wherein the shifting tool does not engage the inside
diameter of the temporary lockout sleeve to move the
sleeve.
It is another object of the invention to provide
a subsurface safety valve including an operator tube
which may be operated by an alternative shifting tool
to check the proper functioning and full travel of the
operator tube of the safety valve.
Still another object of the invention is to
provide a subsurface safety valve including a modified
operator tube and an alternative shifting tool ~7hich may
be used to move the operator tube of the valve to free
the operator tube or valve closure mear.s when jammed by
sand or other well debris.
Additional objects and advantages of the present
invention will be apparent to those skilled in the art
from studying the following detailed description in
conjunction with the accompanying drawings in which
several preferred embodiments of the invention are shown.
~o In the drawings:-
Fig. 1 is a schematic sectional elevation
; illustratlng a typical well completion including a tubing
retrievable subsurface safety valve with a flapper type
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MRR041186 - 6 -
valve closure means;
Figs. 2A, 2B, 2C and 2D taken together form a
longitudinal part-sectional elevation illustrating a
subsurface safety valve and lockout sleeve incorporating
the present invention showing the safety valve in its
open position;
Figs. 3A and 3B taken together form a longitudinal
part-sectional elevation illustrating one embodiment of
the shifting tool fo the present invention;
Fig. 4 is a section taken along the line 4-4 of
Fig. 3;
Figs. 5A, 5B and 5C taken together forrn a long-
itudinal part-sectional elevation showing the safety
valve of Figs. 2A to 2D with the valve closure means open,
the lockout sleeve of the safety valve in its inoperative
position, and the shifting tool of Fig. 3 engaged there-
with;
Figs. 6A, 6B and 6C taken together form a view
similar to Figs. 5A, 5s and 5C showing the shifting tool
and the safety valve after shifting of the lockout sleeve
to hold open the valve closure means;
~ Figs. 7A, 7B and 7C taken together form a view
similar to Figs. 6A to 6C showing the shifting tool
released from the operator tube in the safety valve after
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MRR041186 - 7 -
shifting the lockout sleeve to hold open the valve
closure means;
Fig. 8 is a view similar to Figs. 7B and C
showing the valve closure means temporaxily locked open
with the shifting tool removed;
Figs. 9A and 9B taken together form a longitudin-
al part-sectional elevation illustrating an alternative
embodiment of the shifting tool; and
Figs. 1OA and 10B taken together form a longitud-
inal part--sectional elevation illustrating another
alternative embodiment of the shifting tool.
Referring firstly to Fig. 1, a well completion 20
includes a casing string 28 extending from the well
surface to a hydrocarbon producing formation (not shown),
a tubing string 21 is concentrically disposed within the
casing string 28 and extends froln wellhead 23 through a
production packer 22 which seals between the tubing
string 21 and the casing 28. The packer 22 directs
formation fluids, such as oil, gas, water or the like,
into the tubing string 21 from perforations (not shown)
in the casing 28, which perforations admit formation
fluids into the well bore. Flow control valves 24a and
24b at the well surface control fluid flow from the tubing
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string 21. ~ wellhead cap 27 is provided on the well-
head 23 to perrnit servicing of the well 20 via the
tubiny striny 21 by wireline techniques which include
the installation and removal of various flow control
devices such as valves (not shown) from within the
tubing string 21. Other well servicing operations which
may be carried out through the tubing string 21 are
bottom hole temperature and pressure surveys.
A surface controlled subsurface safety valve 30
embodying the features of the invention is installed in
the well 20 as a part of the tubing striny 21 to control
fluid flow to the well surface via the tubing striny 21
from a downhole location. The safety valve 30 is
operated by control fluid conducted from a hydraulic
manifold 25 at the well surface via a control line con-
duit 26 which directs control fluid signals to the safety
valve 30. The hydraulic manifold 25 generally includes
pumps, a fluid reservoir, accumulators, and control
valves (not shown in detail) for the purpose of providing
control fluid pressure siynals for holding the safety
valve 30 open or allowing this valve 30 to close when
deslred. The manifold 25 also includes apparatus which
functions in response to temperature, sur~ace line leaks,
and other emeryency conditions under which the well 20
should be shut in.
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The safety valve 30 includes flapper type valve
closure means 31 mounted by hinge 34 (see Fiy. 2C) for
swinging ebtween a closed position schematically
represented in Fig. 1 and an open position which permits
fluid flow in tubiny string 21. ~hen a predetermined
pressure signal is applied to the safety valve 30 throuyh
the control line 26 f~om the manifold 25, the valve
closure means 31 is maintained in its first or open
positionO When the control pressure signal is released,
the valve 30 is allowed to move ot its second or closed
position. In accordance with tlle invention, a lockout
sleeve 50 is provided in the valve 30 for movement between
a first yosition which holds the valve closure Means or
flapper 31 ouen and a second position in wl1ich the valve
closure means or flapper 31 is free to open or close. ~qith
the flapper 31 restrained open hy the lockout sleeve 50,
various well servicing operations may be conducted without
fear o~ inadvertent closure of the valve 30 wllich can be
damaging to the servicing equipment.
Details o~ the construction of a preferred form of
the safety valve 30 and the lockout sleeve 50 are shown in
Fiys. 2A to 2D. A shifting tool 70 ~or operati~g the lock-
out sleeve 50 is illustrated in Figs. 3A and 3B and will
; also be described in detail. ~he subsur~ace safety valve
25 30 has housing means 60 formed by a top sub 61a, a~bottom
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MRR041186 - 10 -
sub 61b, and interconnected housing subassemblies 62,
63, 64, 65 and 66 which are suitably interconnected by
threaded joints as illustrated. The housiny means 60
can be generally described as being a long thick-walled
cylinder with a longitudinal bore 67 extending there-
through. The top and bot~om subs 61a and 61b may be
internally or externally threaded to provide means on
opposite ends of the housiny means 60 for connection
with the tubing string 21 as represented in Fig. 1. The
top sub 61a includes locking grooves 68 machined on its
inside diameter. The loc]cing grooves 58 provide means
for installing a secondary or retrievable safety valve
(not shown) within the longitudinal bore 67 if the safety
valve 30 should become inoperative. The secondary valve
may be designed to operate in response to the same
control signal as the safety valve 30 or may be designed
to respond directly to changing well conditions.
The housing subassernbly 62 has a threaded
connection 29 to allow connection of the control line 26
to the safety valve 30. Control fluid pressure signals
are communicated from the well surface via the control
line 26, the threaded connection 29, a passageway 81, and
an opening 82 to the longitudinal bore 67. A cylinder 83
is positioned within the longitudinal bore 67 adjacent
to the opening 82. During norsnal operation of the safety
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MRR041186
valve 30, control fluid pressure signals are directed
to an operator tube 40 via an annular passayeway 84
formed between the inside diameter of the housing
subassembly 62 and the outside diameter of the cylinder 83.
S A perman~nt lockout sleeve 80 is slidably
disposed within the longitudinal bore 67. This permanent
lockout sleeve 80 is sixed to fit concentrically within
the cylinder 83. During normal operation of the safety
valve 30, a knockout plug 85 holds the permanent lockout
sleeve 80 in its inactive position shown in Fig. 2A. If
the safety valve 30 should become inoperative, a profile
86 on the inside diameter of the permanent lockout sleeve
80 can be engayed by a suitable shifting tool (not shown)
to force the sleeve 80 into abutting contact with the
operator tube 40 and to open the safety valve 30. Move-
ment of the sleeve 80 causes the knockout plug 85 to shear,
allowing communication fo control fluid pressure signals
therethrough, A snap riny 87 is carried by the housing
subassembly 62 within the longitudinal bore 67 to lock the
sleeve 80 in place after it has moved. Matchiny teeth 88
are carried on the outside diameter of the sleeve 80 and
the inside diameter of the snap ring 87. The use of
locking grooves or recesses 6~, the permanent locking
sleeve 80, and associated components to instal a secondary
safety valve within a bore, such as the longitudinal bore
67, is~well known in the art.
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MRR041186 - 12 -
Operator tube 40 is slidably disuosed within the
longitudinal bore 67 to shift the valve closure rneans
31 from lts second, closed position to its first, open
position as shown in Fig. 2C. For ease of manufacture
5 and assembly, the operator tube 40 is constructed from
ts~lo generally hollow cylindrical subassemblies desiyn-
ated 40a and 40b. These subassemblies 40a and 40b are
joined together by a threaded connection 41. Movable
piston seal means 42 is carried on the exterior of the
10 operator tube 40 to form a sliding fluid barrier with
the inside diameter of the housing subassembly 63
adjacent thereto. Stationary seal means 43 is carried
by the cylinder 83 to form a fluid barrier with the
exterior of the operator tube 40. The stationary seal
15 means 43, the movable piston seal means 42, and the
exterior of the operator tube 40 therebetween define in
part a variable volume control fluid chamber 48. Control
fluid pressure from the annular passageway 84 is received
within the chamber 48 to act upon the piston seal means
20 42 and to slide the operator tube 40 longitudinally
towards the valve closure means 31 in response thereto.
Biasing means in the form of a spring 44 is carried on
the exterior of the operator tube 40 between a shoulder
64a on the inside diameter of the housing subassembly 64
25 and a shoulder 45 on the exterior of the operator tube
40. This biasing means 44 applies a force to shift the
operator tube 40 longitudinally opposite from control
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fluid pressure in the chamber 48. ~7hen control ~luid
pressure in the chamber 4~ is decreased below a pre-
selected value, the spring 44 moves the operator tube 40
longitudinally upwards to allow the valve closure means
31 to return to its closed position. A spring 35 coiled
around the hinge 34 also assists in moving the flapper 31
to its closed position.
A selective key profile 46 is formed on the interior
of the operator tube 40 intermediate the ends thereof.
This profile 46 provides means for releasably enyaging the
operator tube 40 with a shiftiny tool whereby the shifting
tool can move the operator tube 40 inde~endently of the
control signal. The use of shifting tools 70, 170, and
270 with respect to the profile 46 and the operator tube
40 will be described later in detail. The configuration
and dimensions of the profile 46 are selected to be
different from the locking recess 68 and the proEile 86.
Therefore, the operator tube 40 can be engaged only by a
shifting tool having selective keys which the match
profile 46.
The lockout sleeve 50 which is a second lockout
sleeve, is slidably disposed in the housing means 60 in
tandem with the operator tube 40. In comparison to first
lockout sleeve 80, the second sleeve 50 can be classified
as a temporary lock~ut device. ~his lockout sleeve S0
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MRR041186 - 14 ~
has a first position, shown in Eig. 8, which holds the
valve closure Ineans 31 in its first position, and a
second position, shown in Fig. 2D, which does not
restrict movement of the valve closure nleans 31 hetween
its first and second positions. ~s sho~m in Fiys. 2D
and 8, the lockout sleeve 50 has a relatively smooth
uniform inside dialneter. Therefore, it is dificult for
a wireline tool accidentally to enyage the loc~;out sleeve
50 and shift it to an undesired position. The smooth,
uniform inside diameter of the lockout sleeve 50 is an
important preferably feature of the present invention.
A plurality of longitudinal slots 51 are machined
through the sleeve 50 intermediate the ends thereof.
These slots 51 are circumferentially s~aced to provide
a plurality of collet fingers 52. An external boss 53
is provided on each collet finger 52. Internal grooves
54 and 55 are provided on the interior of the housing
subassembly 66 to receive the bosses 53 therein. The
yrooves 55 and 54 are spaced longitudinally from each
other to correspond respectively with the first position
and second position for the lockout sleeve 50. The
collet fingers 52, the bosses 53, and the cJrooves 54
and 55 cooperate to provide Ineans for releasahly
holding the lockout sleeve 50 in its first or second
position.
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MRR041186 ~ 15 -
Longitud~nal movement of the lockout sleeve 50
within the lon~itudinal bore 67 is limited by a shoulder
66a on the interior of the housing subasselnbly 66
contacting a shoulder 57 on the eY.terior of -the sleeve
50 and by the sleeve 50 resting on a spacer ring 69.
As best shown in Fig. 2DI the insi~e diameter of the
spacer ring 69 is larger than eithsr the sleeve 50 or
the bottom sub 61b of the housing. The spacer ring 69
is used to define a recess 58 in the housing means 60
below the lockout sleeve 50. It will be explained later
how the recess 58 is used to shift the lockout sleeve 50
to its first position.
The shiftin~ tool 70, shown in figs. 3A and B, is
used to shift the lockout sleeve 50 from its second to
its first position. This shifting tool 70 is adapted
for insertion into the longitudinal bore 67 by use of
conventional wireline techniques. The shiftiny tool 70
has an inner mandrel or core means 71 slidably disposed
within cylindrical housing means 72. Fore ease of
manufacture and assembly, the core means 71 comprises
several subsections 71a, 71b and 71c. The subsections
71a and 7ib are two generally solid cylindrical rods
connected to each other by threads 73. ~ fish~ny neck
74 is provided on the upper end of the subsection 71a,
whioh extends from housing means 72~ This fishing neck
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74 provides means for attaching the shifting tool 70 to
a conventional wireline tool stri,ng (not shown).
The housing means 72 comprises several generally
hollow cylindrical subsections desiynated 72a, 72b, and
72c which are attached to each other by appropriate
threaded connections. During initial insertion of the
shifting tool 70 into the longitudinal bore 67, a first
releasable means, in the Eorm of a shear pin 75, extends
through both the core means 71 and the housing means 72,
as shown in fig. 3A, to prevent undesired relative
longitudinal movement therebetween.
A plurality of selectivP keys 76 are disposed
within windows 77 extending through the housing subsection
72a. Leaf springs 78 are carried on the inside diameker
o~ the subsection 72a adjacent to these selective keys
76. The sprinys 78 are designed to project the keys 76
radially outward through the windows 77. The core means
71 has a reduced diameter portion 91 which allows the keys
76 to be compressed radialIy inward by restrictions in
20~ either the tubing string 21 or the safety valve 30. The
shear pin 75 is used to hold the reduced dialneter portion
91 radially adjacent to the keys 76 durin~ insertion of
the tool 70. A plurality of bosses 92 are provided on
the reduced diameter portion 91 adjacent to each key 76.
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MRR041186 _ 17 -
The bosses 92 and the interiors oE the keys 76 are
designed to allow inward compression of the keys 76 when
the shear pin 75 i5 installed.
The ]seys 76 each have an exterior profile which
matches the profile 46 of the operator tube 40. Engage-
ment of the ~ys 76 with the profile 46 prevents further
downward movement of the shifting tool 70 relative to the
safety valve 30 due to the presence of square shoulders
93 and 94 (see Figs~ 3A and 2B). Force can then be
applied to the core means 71 to shear the ~in 75 and
slide the core means 71 longitudinally relative to the
housing means 72. This longitudinal movement positions
the bosses 92 radially adjacent to and contacting a
uortion of their respective keys 76 to lock the keys 76
radially projected as shown in Fig. 5A.
A second shear pin 95 is carried by the housing
subsection 72a and is biased radially inwards by a leaf
spring 96. The exterior of the core means 71 has an
annuIar groove 97 formed on its exterior. The location
of this annular groove 97 is selected so that the shear
pin 75 will normally hold the groove 97 spaced longit-
udinally from the second shear pin 95. When the core
means 71 moves relative to the housing means 72, the
groove 97 1s designed to be engaged by the second shear
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MRR041186 - 18 -
pin 95. The groove 97 and the shear pin 95 cooperate
to provide second releasable means for preventing
undesired relative movernent between the core rneans 71
and the housing means 72 to hold the keys 76 radially
expanded.
The shifting tool 70 has a plurality of latching
dogs 100 space longitudinally from the selective keys
76. These latching dogs 100 are slidahly disposed
within second windows 101 of the housing subsection 72c.
A leaf spring 102 is provided to project each dog 100
radially outward. The inner core means section 71c has
a reduced diameter portion 103 which allows the dogs 100
to be compressed radially inward by restricting in the
tubing string 21 including portions of the safety valve
30. The dogs 100 are specifically sized to fit within
the recess 58 below the lockout sleeve 50.
The shear pln 75 normally holds the reduced diameter
portion 103 radially adjacent to the dogs 100. When the
pin 75 is sheared, the core means 71 can move longitud-
inally to position an enlarged outside diameter portion104 of subsection 71c radially adjacent to the dogs 100.
The enlarged portion 104 prevents the dogs 100 from
flexing radlally inwards. The second shear pin 95 and the
annular groove 97 cooperate to lock the dogs 100 radially
expanded.
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MRR041186 - 19 -
Operating se~uence
For purposes of describing the operation of this
embodiment, it will be asswlled that the safety valve
30 is installed in a well cornpleted as shown in Fig. 1.
Control fluid pressure is communicated from the manifold
25 via the control line 26 to the housing means 60 of
the safety valve 30. Using standard well servicing
techniques and surface wireline equipment (not shown),
the shifting tool 70 is introduced into the tubing string
21 via the wellhead cap 27.
In Figs. 5A, 5J~, and 5C, the safety valve 30 is
shown in its first position with control fluid pressure
in the chamber 48 acting on the operator tube 40 to hold
the flapper 31 open. ~ wireline tool string (not shown)
would be attached to the fishing neck 74 to enable the
shifting tool 70 to be manipulated within the longitudinal
bore 67. The selective keys 76 are engaged with the
profile 46 in the operator tube 40 to prevent further
downward movement of the shifting tool 70 relative to the
safety valve 30. This engagement allows force to be
applied to the fishing neck 74 by the wireline tool string
to shear the pin 75 into two pieces 75a and 75b as shown
in fig. 5A. I'he force applied to the fishiny neck 74
causes the inner core means 71 to slide longitudinally
downward until the fishing neck 74 rests on the top of
25 the housing means 72. This downward movement of the
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MRR041186 - 20 -
core means 71 will position the bosses 92 behind their
respective keys 76 and -the enlarged outside diameter
portion 104 behind the dogs 100. Leaf spring g6 will
force the shear pin 95 into the annular recess 97 which
locks the keys 76 and the latching doys 100 in their
radially expanded conditions.
With the safety valve 30 and the shiftiny tool 70
positioned as shown in figs. 5A, 5B, and 5C, the next
step towards temporarily locking open the safety valve
30 is to decrease control fluid pressure in the chamber
48 below a preselected value. Since the keys 76 are
locked into the profile 46 and the latching dogs 100 are
locked outward into the recess 58, the operator tube 40
and the lockout sleeve 50 ~nust mvoe in unison. Force
can be applied to the shifting tool 70 via the wireline
attached to the fishing neck 74 to assist the spring 44
in shifting the operator tube 40 to its second position
and the lockout sleeve 50 to its first position as shown
in Figs. 6A, 6BI and 6C.
With the Iockout sleeve 50 in its first position,
additional upward force can be applied to the fishing
neck 74 to shear the pin 95 into two pieces as indicated
at 95a and 95b. The inner core means 71 is then free to
move to its initial longitudinal position with respect to
the housing means 72 which allows the ke~s 76 and the
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MRR041186 - 21 -
latch dogs 100 to be compressed raially in~7ard. Figs.
7A and 7B show the shifting tool 70 in this configura-
tion while it is being withdrawn frorn the lonyitudinal
bore 67.
The final result of these operations is shown in
Fig. 8. The lockout sleeve 50 is in its first position
holding the flapper 31 open. The operator tube 4~ has
been returned to its second position. The shifting tool
70 has been removed from the longitudinal bore 67. ~s
previously noted, the smooth uniform inside diameter of
the lockout sleeve 50 greatly reduces the possibility~
of a wireline service tool or iools accidentally shift-
ing the sleeve 50 and returning it to its second
position. When the desired well maintenance has been
completed, the safety valve 30 can be returned to normal
operation by simply applying control fluid pressure to
the chamber 48. This pressure causes the operator tube
40 to move to its first position. During this movement~
the operator tube 40 abuts the second lockout sleeve 50
and returns such sleeve 50 to its second position.
During the initial installation oE the tubing
string 21 withing the casing 28, the lockout sleeve 50
can be used to check the integrity o the control line
26 and the proper functioning of the safety valve 30.
During installation, the safety valve 30 is preferably
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MR~041186 - 22 -
attached to the tubing string 21 wi~,h the valve closuremeans 31 and the lockout sleeve 50 both in their first
position. The collet fingers 52, the bosses 53 and the
groove 55 are designed to allow a substantial amount of
control fluid pressure to be applied to the chamber 48
before the operator tube 40 can shift the lockout sleeve
50 to its second position. By applying less than this
amount of pressure to the control line 26 from the
manifold 25, the integrity of the control line 26 can be
monitored. A drop in the control line pressure or a
decrease in control fluid level at the manifold 25
indicates a possible leak in the control line 26 which
should be investigated before completing the well 20.
After the tubing string 21 is properly disposed within
the casing 28, sufficient pressure can be applied to the
control line 26 to shift the lockout sleeve 50 to its
second position. Proper operation of the safety valve
30 can be verified by monitoring the control line
pressure and volume required for this shifting.
Alternative ~mbodiments
The above description has been directed towards an
operator tube which opens a flapper type valve closure
means. U.S. Patent 3r860,066 to Joseph L. Pearce el al
demonstrates that the operator tube 40 could be modified
to open and close ball ~ype and poppet type valve
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MRR041186 - 23 -
closure means as alternatives to the flapper 31.
Therefore, the present invention is not limited to
flapper valves. The shifting tool 170 shown in Figs.
9A and 9~ may be used to cycle any type of valve
closure means between its open and closed position as
long as the valve operator tube has been modified for
releasable engagement with the tool 170. Generally,
the shifting;tool 170 will be used to open the valve
closure means, ~lowever, it could be used to move the
operator tube 40 to close the valve closure means if
required.
Some components and features of the shifting
tool 170 are identical to those of the shifting tool 70
and have given the same ~eference numerals). The
principal structural differences between the shifting
tool 170 and the above-described shifting tool 70 are
the replacement of the fishing neck 74 by an equalis-
ing valve and packing assembly 180 and removal of the
core means subsections 71b and 71c and the housing means
subsections 72b and 72c. The principal operating
differences are that the equalising valve and packing
assembly 180 allows fluid pressure in the tubing string
21 to be applied to the operator tube 40, and latching
dogs 100 a~e not provided to shift the lockout sleeve 50.
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~lRR041186 - %4 -
The eyualising valve and packing assembly 180
as shown in Fig. 9A includes a fishing neck 174 for
attachment to a standard wireline tool string. This
fishing neck 174 is connected by threads to a poppet
valve plunger 181 which is slidably disposed in a
valve housing 182~ Ports 183 communicate fluid
between the interior and exterior of the valve housing
182. A valve seat 184 is disposed within the valve
housing 182 for engagement with the valve plunger 181.
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A packing carrier 185 is attached to the valve
housing 182 by threads 187. Packing or seal means 186
is carried on the exte~ior of the packing carrier 185.
The dimensions of the seal means 186 are selected to
form a fluid barrier with the inside diameter of the
housing top sub 61a when the shifting tool 170 is
engaged wi~h the operator tube 40. A hollow longitud-
inal spacer 188 is used to attach the packing carrier
185 to the core means section 71a by suitable threaded
connections. A longitudinal flow passageway 189
extends through the valve housing 182, the packing
carrier 185 and the spacer 188. A p'~et 190 communi-
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cates between the exterior of the spacer 188 and thelongitudinal flow passageway 189.
During installation of the shifting tool 170, the
plunger 181 is spaced longitudinally above the valve
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MRR041186 - 25 -
seat 184 to allow fluid in the tubing string 21 to
bypass the seal means 186. When the keys 76 engage the
profile 46, the plunger 1~1 is lowered to contact the
valve seat 184 to block fluid flow via the lonyitud-
inal passageway 189. The length of the spacer 188is preferably selected ~o that the seal means 186 form
a fluid barrier with the inside diameter of housing
bottom sub 61a immediately below the locking recesses
68. Hydraulic fluid pressure can then be applied from
the well surface via the tubing string 21 to act on
the seal means 186. Since the effective piston area of
the seal means 186 is much larger than the piston seal
means 42 carried by the operator tube 40, the shifting
tool 170 can apply considerably more force to the
operator tube 40 to cycle the valve. closure means 31.
This feature may be particularly desirable for ball
type valve closure means. ~lso, the spacer 188 could
be removed if the operator tube 40 is modified to allow
the seal means 186 to form a fluid barrier therewith.
The shifting tool 170 is released from engagement
with the operator tube 40 in the same manner as
previously described for the shiftiny tool 70. When
sufficient upward force is applied to the fishing neck
174 to shear the pin 95, the core means subsection 71a
will move upwards to allow the keys to be compressed
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MRR0411~6 - 26 -
radially inwards.
The above described has also been directed
towards a safety valve ~hich is opened and closecl
in response to a hydraulic fluid control signal from
the well surface. The present invention can be used
with any type of safety valve control signal includ-
ing electrically operated valves such as shown in
U.S. Patent 3,731,742 to Phillip S. Sizer et aL or
U.S. Patent 4,002,202 to Louis s. Paulos et al.
Another alternative embodiment of the present
invention involves shifting tool 270 shown in Figs.
1OA and 10s and allows both the opening of a safety
valve and locking the valve open, if desired, without
regard to the presence of the valve's normal control
signal. Thls embodiment is particularly important as
a backup feature for safety valve control systems
which use electrical, electronic, sound, electro-
hydraulic, hydraulic pilot or similarly sophisticated
control systems. During periods when the sophisticated
control systems are being reuaired, the shifting tool
270 aIlows a safety valve having an operator tube with
the profile ~6 and the lockout sleeve 50 to be temp-
orarily locked open without regard to the presence
of the normal control signal. A direct-acting safety
valve would preferably be installed until repair of the
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~1RR041186 - 27 -
control system had been completed. Therefore, the
present invention i5 not limited to hydraulically
controlled safety valves and may in fact provide
sufficient reliability to make more complicated control
systems commercially acceptable for downhole safety
valves.
In the event of a serious control line leak, it
may not be desirable to use the permanent lockout
sleeve 80 to shift the valve closure means 31 to its ;
first position because formation fluids can then escape
via the control line leak. The shifting tool 270
allows the valve closure means 31 to be lacked open
without the use of control fluid pressure and without
disturbing the permanent lockout sleeve 80. A direct
acting safety valve or STORM CHOKE (Registered Trade Mark)
safety valve which does not require hydraulic control
fluid can then be installed within the longitudinal
bore 67 to maintain well safety. Prior to the present
invention, the only solution to a serious control line
leak was to remove the tubing string 21 from the well
bore, which is a very expensive procedure.
The shiPting tool 270 is substantially identical
with the shiftiny tool 70, except that the fishiny neck
74 has been replaced by the equalising valve and packing
assembly 180 of the shifting tool 170. The shifting tool
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~IRR041186 - 28 -
270 can use fluid pressure in the ~ubing string 21 to
open the valve closure means 31 as previously described
for the shifting tool 170. The shiftinc3 tool Z70 can
be manipulated by a wireline tool string attached to
the fishing neck 174 to shift the lockout sleeve 50
to its first position as previously described for the
shifting tool 70.
The above description is illustrative of only
some of the embodiments of the invention. Those
skilled in the art will readily visualise other
variations for a shifting tool and subsurface safety
valve utilising the present invention. Changes and
modifications may be made without departing from the
scope of the invention which is defined by the following
claims.
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