Note: Descriptions are shown in the official language in which they were submitted.
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WELL TOOL ACTUATOR AND
ISOLATION VALVE FOR USE IN DRILLING OPERATIONS
TECHNICAL FIELD
This disclosure relates generally to equipment utilized
and operations performed in conjunction with a subterranean
well and, in an embodiment described herein, more
particularly provides an isolation valve for use in drilling
operations.
BACKGROUND
An isolation valve can be used in a drilling operation
for various purposes, such as, to prevent a formation from
being exposed to pressures in a wellbore above the valve, to
allow a drill string to be tripped into and out of the
wellbore conventionally, to prevent escape of fluids (e.g.,
gas, etc.) from the formation during tripping of the drill
string, etc. Therefore, it will be appreciated that
improvements are needed in the art of operating isolation
valves in drilling operations. These improvements could be
used in other types of well tools, also.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a representative partially cross-sectional
view of a well system and associated method which can embody
principles of this disclosure.
FIG. 2 is a representative quarter-sectional view of a
drilling isolation valve which may be used in the system and
method of FIG. 1, and which can embody principles of this
disclosure.
FIG. 3 is a representative quarter-sectional view of
the drilling isolation valve actuated to a closed
configuration.
FIG. 4 is a representative quarter-sectional view of
the drilling isolation valve actuated to an open
configuration.
FIG. 4A is a representative quarter-sectional view of
another example of the drilling isolation valve.
FIGS. 5A & B are representative quarter-sectional views
of another example of the drilling isolation valve in open
and closed configurations thereof.
DETAILED DESCRIPTION
Representatively illustrated in FIG. 1 is a well system
10 and associated method which can embody principles of this
disclosure. In this example, a wellbore 12 is lined with a
casing string 14 and cement 16. A drill string 18 having a
drill bit 20 on an end thereof is used to drill an uncased
section 22 of the wellbore 12 below the casing string 14.
A drilling isolation valve 24 is interconnected in the
casing string 14. The isolation valve 24 includes a closure
26, which is used to selectively permit and prevent fluid
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flow through a passage 28 extending through the casing
string 14 and into the uncased section 22.
By closing the isolation valve 24, an earth formation
30 intersected by the uncased section 22 can be isolated
from pressure and fluid in the wellbore 12 above the closure
26. However, when the drill string 18 is being used to
further drill the uncased section 22, the closure 26 is
opened, thereby allowing the drill string to pass through
the isolation valve 24.
In the example of FIG. 1, the closure 26 comprises a
flapper-type pivoting member which engages a seat 32 to seal
off the passage 28. However, in other examples, the closure
26 could comprise a rotating ball, or another type of
closure.
Furthermore, it should be clearly understood that the
scope of this disclosure is not limited to any of the other
details of the well system 10 or isolation valve 24 as
described herein or depicted in the drawings. For example,
the wellbore 12 could be horizontal or inclined near the
isolation valve 24 (instead of vertical as depicted in FIG.
1), the isolation valve could be interconnected in a liner
string which is hung in the casing string 14, it is not
necessary for the casing string to be cemented in the
wellbore at the isolation valve, etc. Thus, it will be
appreciated that the well system 10 and isolation valve 24
are provided merely as examples of how the principles of
this disclosure can be utilized, and these examples are not
to be considered as limiting the scope of this disclosure.
Referring additionally now to FIG. 2, an enlarged scale
quarter-sectional view of one example of the isolation valve
24 is representatively illustrated. The isolation valve 24
of FIG. 2 may be used in the well system 10 of FIG. 1, or it
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may be used in other well systems in keeping with the
principles of this disclosure.
The isolation valve 24 is in an open configuration as
depicted in FIG. 2. In this configuration, the drill string
18 can be extended through the isolation valve 24, for
example, to further drill the uncased section 22. Of course,
the isolation valve 24 can be opened for other purposes
(such as, to install a liner in the uncased section 22, to
perform a formation test, etc.) in keeping with the scope of
this disclosure.
In one novel feature of the isolation valve 24, an
actuator 33 of the valve includes a sensor 34 which is used
to detect acoustic signals produced by movement of the drill
string 18 (or another object in the wellbore 12, such as a
liner string, etc.). The movement which produces the
acoustic signals may comprise reciprocation or axial
displacement of the drill string 18, rotation of the drill
string, other manipulations of the drill string,
combinations of different manipulations, etc.
Preferably, a predetermined pattern of drill string 18
manipulations will produce a corresponding predetermined
pattern of acoustic signals, which are detected by the
sensor 34. In response, electronic circuitry 36 actuates one
of a series of valves 38a-f.
Each of the valves 38a-f is selectively openable to
provide fluid communication between a passage 40 and a
respective one of multiple chambers 42a-f. The chambers 42a-
f are preferably initially at a relatively low pressure
(such as atmospheric pressure) compared to well pressure at
the location of installation of the isolation valve 24 in a
well. The chambers 42a-f are also preferably initially
filled with air, nitrogen or another inert gas, etc.
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A piston 44 separates two fluid-filled chambers 46, 48.
The chamber 46 is in communication with the passage 40.
Upon installation, the chamber 48 is in communication
with well pressure in the passage 28 via an opening 50a,
which is aligned with an opening 52 in a tubular mandrel 54.
Thus, the chamber 48 is pressurized to well pressure when
the isolation valve 24 is installed in the well.
The chamber 48 is in communication with another chamber
56. This chamber 56 is separated from another chamber 58 by
a piston 60. The chamber 58 is preferably at a relatively
low pressure (such as atmospheric pressure), and is
preferably initially filled with air, nitrogen or another
inert gas, etc.
The piston 60 is attached to a sleeve 62 which, in its
position as depicted in FIG. 2, maintains the closure 26 in
its open position. However, if the sleeve 62 is displaced to
the left as viewed in FIG. 2, the closure 26 can pivot to
its closed position (and preferably does so with the aid of
a biasing device, such as a spring (not shown)).
In order to displace the sleeve 62 to the left, the
piston 60 is displaced to the left by reducing pressure in
the chamber 56. The pressure in the chamber 56 does not have
to be reduced below the relatively low pressure in the
chamber 58, since preferably the piston 60 area exposed to
the chamber 56 is greater than the piston area exposed to
the chamber 58, as depicted in FIG. 2, and so well pressure
will assist in biasing the sleeve 62 to the left when
pressure in the chamber 56 is sufficiently reduced.
To reduce pressure in the chamber 56, the piston 44 is
displaced to the left as viewed in FIG. 2, thereby also
displacing a sleeve 64 attached to the piston 44. The sleeve
64 has the opening 50a (as well as additional openings
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50b,c) formed therein. Together, the piston 44, sleeve 64
and opening 52 in the mandrel 54 comprise a control valve 65
which selectively permits and prevents fluid communication
between the passage 28 and the chamber 48.
Initial displacement of the sleeve 64 to the left will
block fluid communication between the openings 50a, 52,
thereby isolating the chamber 48 from well pressure in the
passage 28. Further displacement of the piston 44 and sleeve
64 to the left will decrease pressure in the chamber 48 due
to an increase in volume of the chamber.
To cause the piston 44 to displace to the left as
viewed in FIG. 2, the valve 38a is opened by the electronic
circuitry 36. Opening the valve 38a provides fluid
communication between the chambers 42a, 46, thereby reducing
pressure in the chamber 46. A pressure differential from the
chamber 48 to the chamber 46 will cause the piston 44 to
displace to the left a distance which is determined by the
volumes and pressures in the various chambers.
The valves 38a-f are preferably openable in response to
application of a relatively small amount of electrical
power. The electrical power to open the valves 38a-f and
operate the sensor 34 and electronic circuitry 36 can be
provided by a battery 66, and/or by a downhole electrical
power generator, etc.
Suitable valves for use as the valves 38a-f are
described in US patent application no. 12/353,664 filed on
January 14, 2009, the entire disclosure of which is
incorporated herein by this reference. Of course, other
types of valves (such as, solenoid operated valves, spool
valves, etc.) may be used, if desired. A preferred type of
valve uses thermite to degrade a rupture disk or other
relatively thin pressure barrier.
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Referring additionally now to FIG. 3, the isolation
valve 24 is representatively illustrated after the valve 38a
has been opened in response to the acoustic sensor 34
detecting the predetermined pattern of acoustic signals
resulting from manipulation of the drill string 18. Note
that the piston 44 and sleeve 64 have displaced to the left
due to pressure in the chamber 46 being reduced, and the
piston 60 and sleeve 62 have displaced to the left due to
pressure in the chamber 56 being reduced.
The closure 26 is no longer maintained in its FIG. 2
open position, and is pivoted inward, so that it now seals
off the passage 28. In this configuration, the formation 30
is isolated from the wellbore 12 above the isolation valve
24.
The isolation valve 24 can be re-opened by again
producing a predetermined pattern of acoustic signals by
manipulation of the drill string 18, thereby causing the
electronic circuitry 36 to open the next valve 38b. A
resulting reduction in pressure in the chamber 46 will cause
the piston 44 and sleeve 64 to displace to the left as
viewed in FIG. 3. The predetermined pattern of acoustic
signals used to open the isolation valve 24 can be different
from, or the same as, the predetermined pattern of acoustic
signals used to close the isolation valve.
Referring additionally now to FIG. 4, the isolation
valve 24 is representatively illustrated after the valve 38b
has been opened in response to the acoustic sensor 34
detecting the predetermined pattern of acoustic signals
resulting from manipulation of the drill string 18. Note
that the piston 44 and sleeve 64 have displaced to the left
due to pressure in the chamber 46 being reduced, and the
piston 60 and sleeve 62 have displaced to the right due to
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pressure in the chamber 56 being increased. Pressure in the
chamber 56 is increased due to the opening 50b aligning with
the opening 52 in the mandrel 54, thereby admitting well
pressure to the chamber 48, which is in communication with
the chamber 56.
Rightward displacement of the sleeve 62 pivots the
closure 26 outward, so that it now permits flow through the
passage 28. In this configuration, the drill string 18 or
another assembly can be conveyed through the isolation valve
24, for example, to further drill the uncased section 22.
Valve 38c can now be opened, in order to again close
the isolation valve 24. Then, valve 38d can be opened to
open the isolation valve 24, valve 38e can be opened to
close the isolation valve, and valve 38f can be opened to
open the isolation valve.
Thus, three complete opening and closing cycles can be
accomplished with the isolation valve 24 as depicted in
FIGS. 2-4. Of course, any number of valves and chambers may
be used to provide any number of opening and closing cycles,
as desired. The sleeve 64 can also be configured to provide
any desired number of opening and closing cycles.
Note that, it is not necessary in the example of FIGS.
2-4 for the valves 38a-f to be opened in any particular
order. Thus, valve 38a does not have to be opened first, and
valve 38f does not have to be opened last, to actuate the
isolation valve 24. Each of the valves 38a-f is in
communication with the passage 40, and so opening any one of
the valves in any order will cause a decrease in pressure in
the chamber 46.
However, representatively illustrated in FIG. 4A is
another example of the isolation valve 24, in which the
valves 38a-f are opened in series, in order from valve 38a
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to valve 38f, to actuate the isolation valve. Each of valves
38b-f is only placed in communication with the passage 40
when all of its predecessor valves have been opened. Only
valve 38a is initially in communication with the passage 40.
In one method of operating the isolation valve 24 in
the well system 10 of FIG. 1, the drill string 18 itself is
used to transmit signals to the isolation valve, to thereby
actuate the isolation valve. The drill string 18 can be
displaced axially, rotationally, or in any combination of
manipulations, to thereby transmit acoustic signals to an
actuator 33 of the isolation valve 24.
For example, when tripping the drill string 18 into the
wellbore 12, the isolation valve 24 would typically be
closed, in order to isolate the formation 30 from the
wellbore above the isolation valve. When the drill string 18
is within a certain distance of the isolation valve 24, the
drill string is manipulated in a manner such that a
predetermined pattern of acoustic signals is produced.
The sensor 34 detects acoustic signals in the downhole
environment. If the predetermined pattern of acoustic
signals is detected by the sensor 34, the electronic
circuitry 36 causes one of the valves 38a-f to be opened.
The valves 38a-f are opened in succession, with one valve
being opened each time the predetermined pattern of acoustic
signals is detected.
Of course, various different techniques for using
patterns of acoustic signals to communicate in a well
environment are known to those skilled in the art. For
example, acoustic signaling techniques known as
HALSONICS(TM), SURFCOM(TM) and PICO SHORT HOP(TM) are
utilized by Halliburton Energy Services, Inc.
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When the drill string 18 is manipulated in a manner
such that the predetermined pattern of acoustic signals is
produced, the valve 24 is opened. The drill string 18 can
now be extended through the passage 28 in the valve 24, and
drilling of the uncased section 22 can proceed.
When it is time to trip the drill string 18 out of the
wellbore 12, the drill string is raised to within a certain
distance above the isolation valve 24. Then, the drill
string 18 is manipulated in such a manner that the
predetermined pattern of acoustic signals is again produced.
When the acoustic signals are detected by the sensor
34, the isolation valve 24 is closed (e.g., by opening
another one of the valves 38a-f). The drill string 18 can
now be tripped out of the well, with the closed isolation
valve 24 isolating the formation 30 from the wellbore 12
above the isolation valve.
However, it should be understood that other methods of
operating the isolation valve 24 are within the scope of
this disclosure. For example, it is not necessary for the
same predetermined pattern of acoustic signals to be used
for both opening and closing the isolation valve 24.
Instead, one pattern of acoustic signals could be used for
opening the isolation valve 24, and another pattern could be
used for closing the isolation valve.
It also is not necessary for the pattern of acoustic
signals to be produced by manipulation of the drill string
18. For example, the pattern of acoustic signals could be
produced by alternately flowing and not flowing fluid, by
altering circulation, by use of a remote acoustic generator,
etc.
Furthermore, it is not necessary for the actuator 33 to
respond to acoustic signals. Instead, other types of signals
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(such as, electromagnetic signals, pressure pulses, annulus
or passage 28 pressure changes, etc.) could be used to
operate the isolation valve 24.
Thus, the sensor 34 is not necessarily an acoustic
sensor. In other examples, the sensor 34 could be a pressure
sensor, an accelerometer, a flowmeter, an antenna, or any
other type of sensor.
Referring additionally now to FIGS. 5A & B, another
example of the isolation valve 24 is representatively
illustrated. The isolation valve 24 is depicted in an open
configuration in FIG. 5A, and in a closed configuration in
FIG. 5B.
For illustrative clarity, only a lower section of the
isolation valve 24 is shown in FIGS. 5A & B. An upper
section of the isolation valve 24 is similar to that shown
in FIGS. 3-4, with the upper section including the sensor
34, electronic circuitry 36, valves 38a-f, chambers 42a-f,
etc.
In the example of FIGS. 5A & B, the chamber 58 is
exposed to well pressure in the passage 28 via a port 70 in
the sleeve 62. In addition, a biasing device 72 (such as a
spring, etc.) biases the piston 60 toward its open position
as depicted in FIG. 5A.
Thus, when any of the openings 50a-c is aligned with
the opening 52, and well pressure in the passage 28 is
thereby communicated to the chambers 48, 56, the piston 60
is pressure-balanced. The device 72 can displace the piston
60 and sleeve 62 to their open position, with the closure 26
pivoted outward, so that flow is permitted through the
passage 28 as depicted in FIG. 5A.
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When the piston 44 and sleeve 64 displace to the left
(as viewed in FIGS. 5A & B), and the chambers 48, 56 are
isolated from the passage 28, a resulting pressure
differential across the piston 60 will cause it to displace
leftward to its closed position. This will allow the closure
26 to pivot inward and prevent flow through the passage 28
as depicted in FIG. 5B.
It may now be fully appreciated that the above
disclosure provides significant advancements to the art of
operating an isolation valve in a well. The isolation valve
24 described above can be operated by manipulating the drill
string 18 in the wellbore 12, thereby transmitting
predetermined acoustic signal patterns, which are detected
by the sensor 34. The isolation valve 24 may be opened and
closed multiple times in response to the sensor 34 detecting
such acoustic signal patterns. Other methods of operating
the isolation valve 24 are also described above.
The above disclosure provides to the art a drilling
isolation valve 24, which can comprise an actuator 33
including a series of chambers 42a-f which, when opened in
succession, cause the isolation valve 24 to be alternately
opened and closed.
The drilling isolation valve 24 can also include a
control valve 65 which alternately exposes a piston 60 to
well pressure and isolates the piston 60 from well pressure
in response to the chambers 42a-f being opened in succession
(i.e., each following another, but not necessarily in a
particular order). The control valve 65 may comprise a
sleeve 64 which displaces incrementally in response to the
chambers 42a-f being opened in succession.
The actuator 33 can include a sensor 34. The chambers
42a-f may be opened in succession in response to detection
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of predetermined acoustic signals by the sensor 34. The
chambers 42a-f may be opened in succession in response to
detection of drill string 18 movement by the sensor 34. The
sensor 34 may comprise an acoustic sensor.
Also described above is a method of operating a
drilling isolation valve 24. The method may include
manipulating an object (such as the drill string 18) in a
wellbore 12, a sensor 34 of the drilling isolation valve 24
detecting the object manipulation, and the drilling
isolation valve 24 operating between open and closed
configurations in response to the sensor 34 detecting the
object manipulation.
The manipulating may comprise axially displacing the
object, and/or rotating the object.
A series of chambers 42a-f of the drilling isolation
valve 24 may be opened in succession (i.e., each following
another, but not necessarily in a particular order) in
response to the sensor 34 detecting respective predetermined
patterns of the object manipulation. The drilling isolation
valve 24 may alternately open and close in response to the
chambers 42a-f being opened in succession.
A control valve 65 may alternately expose a piston 60
to well pressure and isolate the piston 60 from well
pressure in response to the chambers 42a-f being opened in
succession.
The sensor 34 can comprise an acoustic sensor. The
object manipulation may include transmitting a predetermined
acoustic signal to the sensor 34. The object can comprise
the drill string 18.
The above disclosure also provides to the art a well
system 10. The well system 10 can include a drill string 18
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positioned in a wellbore 12, and a drilling isolation valve
24 which selectively permits and prevents fluid flow through
a passage 28 extending through a tubular casing string 14,
the isolation valve 24 including a sensor 34 which senses
manipulation of the drill string 18 in the tubular string
14, whereby the isolation valve 24 actuates in response to
the sensor 34 detecting a predetermined pattern of the drill
string 18 manipulation.
The isolation valve 24 can include a series of chambers
42a-f which, when opened in succession (i.e., each following
another, but not necessarily in a particular order), cause
the isolation valve 24 to be alternately opened and closed.
The isolation valve 24 may further include a control valve
65 which alternately exposes a piston 60 to well pressure
and isolates the piston 60 from well pressure, in response
to the chambers 42a-f being opened in succession.
The chambers 42a-f may be opened in succession in
response to detection of predetermined acoustic signals by
the sensor 34, and/or in response to detection of the
predetermined pattern of the drill string 18 manipulation.
Although the above description provides various
examples of an isolation valve 24 which is actuated in
response to opening the chambers 42a-f. However, it will be
readily appreciated that the actuator 33 could be used for
actuating other types of valves and other types of well
tools (e.g., packers, chokes, etc.). Therefore, it should be
clearly understood that the scope of this disclosure is not
limited to isolation valves, but instead encompasses
actuation of various different types of well tools.
The above disclosure provides to the art a well tool
actuator 33 which can include a series of chambers 42a-f
that, when opened in succession, cause the well tool (such
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as the isolation valve 24, a packer, a choke or other flow
control device, etc.) to be alternately actuated.
The above disclosure also provides to the art a method
of operating a well tool actuator 33. The method can include
manipulating an object (such as, the drill string 18, etc.)
in a wellbore 12, a sensor 34 of the actuator 33 detecting
the object manipulation, and the actuator 33 actuating in
response to the sensor 34 detecting the object manipulation.
It is to be understood that the various embodiments of
this disclosure described herein may be utilized in various
orientations, such as inclined, inverted, horizontal,
vertical, etc., and in various configurations, without
departing from the principles of this disclosure. The
embodiments are described merely as examples of useful
applications of the principles of the disclosure, which is
not limited to any specific details of these embodiments.
In the above description of the representative
examples, directional terms (such as "above," "below,"
"upper," "lower," etc.) are used for convenience in
referring to the accompanying drawings. In general, "above,"
"upper," "upward" and similar terms refer to a direction
toward the earth's surface along a wellbore, and "below,"
"lower," "downward" and similar terms refer to a direction
away from the earth's surface along the wellbore, whether
the wellbore is horizontal, vertical, inclined, deviated,
etc. However, it should be clearly understood that the scope
of this disclosure is not limited to any particular
directions described herein.
Of course, a person skilled in the art would, upon a
careful consideration of the above description of
representative embodiments of the disclosure, readily
appreciate that many modifications, additions,
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substitutions, deletions, and other changes may be made to
the specific embodiments, and such changes are contemplated
by the principles of this disclosure. Accordingly, the
foregoing detailed description is to be clearly understood
as being given by way of illustration and example only, the
spirit and scope of the invention being limited solely by
the appended claims and their equivalents.
