U.S. patent application number 11/748280 was filed with the patent office on 2008-11-20 for system and method for multi-zone well treatment.
This patent application is currently assigned to SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Thibaut Guignard, John R. Whitsitt.
Application Number | 20080283252 11/748280 |
Document ID | / |
Family ID | 40026354 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080283252 |
Kind Code |
A1 |
Guignard; Thibaut ; et
al. |
November 20, 2008 |
SYSTEM AND METHOD FOR MULTI-ZONE WELL TREATMENT
Abstract
A technique is provided for treating a plurality of well zones
with a service tool during a single trip downhole. The service tool
is run downhole to a selected well zone that is isolated for
treatment. Following treatment of the well zone, the service tool
is moved to a subsequent well zone isolated for treatment. When the
lengths of the well zones to be treated are dissimilar, the active
length of the service tool can be adjusted to correspond with the
well zone length to optimize the well treatment operation.
Inventors: |
Guignard; Thibaut; (Houston,
TX) ; Whitsitt; John R.; (Houston, TX) |
Correspondence
Address: |
SCHLUMBERGER RESERVOIR COMPLETIONS
14910 AIRLINE ROAD
ROSHARON
TX
77583
US
|
Assignee: |
SCHLUMBERGER TECHNOLOGY
CORPORATION
Sugar Land
TX
|
Family ID: |
40026354 |
Appl. No.: |
11/748280 |
Filed: |
May 14, 2007 |
Current U.S.
Class: |
166/381 ;
166/387 |
Current CPC
Class: |
E21B 33/124 20130101;
E21B 43/04 20130101; E21B 43/14 20130101 |
Class at
Publication: |
166/381 ;
166/387 |
International
Class: |
E21B 43/00 20060101
E21B043/00 |
Claims
1. A method of treating a well, comprising: moving a service tool
downhole into a well having a plurality of zones to be treated;
isolating each zone prior to treatment; circulating a treatment
fluid into each isolated zone; providing an entry port into the
service tool to accommodate any returning treatment fluid; and
changing the position of the entry port relative to the service
tool to maintain the entry port proximate a bottom of each isolated
zone when treating subsequent zones having differing lengths.
2. The method as recited in claim 1, wherein moving comprises
running the service tool in-hole with a completion assembly.
3. The method as recited in claim 1, wherein moving comprises
moving the service tool downhole in the form of a washpipe.
4. The method as recited in claim 1, wherein isolating comprises
setting a plurality of isolation packers.
5. The method as recited in claim 1, wherein changing comprises
selectively opening a valve of a plurality of valves positioned
along the service tool.
6. The method as recited in claim 5, wherein selectively opening
comprises sealing the valve in a seal bore positioned proximate an
isolation packer at a downhole end of the zone subject to
treatment; and subsequently opening the valve.
7. The method as recited in claim 5, wherein selectively opening
comprises creating a pressure differential between the treatment
fluid and the next sequential zone downhole of the valve.
8. The method as recited in claim 5, wherein selectively opening
comprises using an internal pressure within the service tool to
open the valve.
9. The method as recited in claim 5, wherein selectively opening
comprises opening the valve with a magnetic force.
10. The method as recited in claim 5, further comprising locking
the valve in an open position.
11. The method as recited in claim 1, further comprising
selectively isolating a bottom of the service tool with the
valve
12. A system for treating a multi-zone well, comprising: a service
tool having a plurality of valves arranged along the service tool,
each valve cooperating with a sealing member; a tubular member
disposed around the service tool, the tubular member having a bore
region sized to form a seal with each valve via the sealing member
as each valve is moved into the bore region; and an isolation
packer disposed externally of the tubular member proximate an
exterior of the bore region, wherein any valve of the plurality of
valves can be moved into sealing engagement with the bore region to
ensure the effective length of the service tool corresponds with
the length of a well zone to be treated.
13. The system as recited in claim 12, wherein each valve is
actuated by one of a group consisting of: (i) pressure actuation,
the pressure actuation requiring formation of a seal via the
sealing member positioned between the valve and the bore region;
(ii) magnetic actuation: and (iii) internal pressure actuation
within the service tool.
14. (canceled)
15. (canceled)
16. The system as recited in claim 12, wherein the service tool has
a bottom opening; and wherein at least one of the valves comprises
an in-line valve that can selectively open and close the bottom
opening.
17. The system as recited in claim 16, wherein the in-line valve is
a one-way valve.
18. The system as recited in claim 16, wherein the in-line valve is
a two-way valve.
19. The system as recited in claim 12, wherein each valve comprises
a lock to lock the valve in an open position.
20. The system as recited in claim 19, wherein the lock is a
hydraulic lock.
21. The system as recited in claim 12, wherein each valve is biased
toward a closed position.
22. A system, comprising: a well treatment system having: a bore
region; an isolation packer disposed proximate an exterior of the
bore region; and a valve selectively movable to a position inside
the bore region for sealing engagement with the bore region,
wherein the valve may be selectively actuated to open an entry port
for admitting fluid into the valve once sealed with the bore
region.
23. The system as recited in claim 22, wherein the valve comprises
a plurality of valves that may be selectively opened when sealed
with the bore region to accommodate treatment of well zones with
differing lengths, and wherein the isolation packer comprises a
plurality of isolation packers located to isolate a plurality of
well zones having differing lengths.
24. (canceled)
25. A method, comprising: sequentially treating a plurality of well
zones with a single trip downhole; and: adjusting the active length
of a service tool according to the length of each well zone treated
while maintaining a fluid return path port proximate a lower region
of the well zone treated.
26. The method as recited in claim 25, wherein sequentially
treating comprises running the service tool in-hole with a
completion assembly.
27. The method as recited in claim 25, wherein adjusting comprises
positioning a plurality of valves along the service tool such that
a valve located at the lower end of an isolated well zone can
selectively be opened.
28. The method as recited in claim 27, wherein the valve located at
the lower end of the well zone is selectively opened by creating a
pressure differential between the pressure of treatment fluid in a
treatment zone and the pressure in an adjacent well zone, and
wherein each valve comprises a seal member positioned to seal with
a seal bore located proximate a tower end of the treatment
zone.
29. (canceled)
Description
BACKGROUND
[0001] Many types of completions are used in sand control
operations. Generally, a slurry or other fluid is circulated
downhole to a well zone to be treated and a return fluid is
circulated back up through the completion. However, installation of
typical sand control completions usually involves several trips
downhole. For example, the installation may require a perforating
trip, a cleanup trip, and a treatment trip. If the well has
multiple zones, each of these processes is repeated for each
zone.
[0002] Single trip multizone systems have been designed and used.
However these systems suffer from a variety of other drawbacks,
including a limited capability for handling well zones of
dissimilar lengths. Some of these systems also are limited by their
use of concentric strings to form the fluid flow paths required for
performing the well treatment operation at multiple well zones.
Other systems can be limited because the fluid flow from the
surrounding reservoir into a central return passage is
substantially axial rather than radial. The resulting effect can be
an inefficient drainage pattern having potential for premature
watering.
SUMMARY
[0003] In general, the present invention provides a system and
method for treating a plurality of well zones with a single trip
downhole. A service tool is run downhole to a selected well zone
that is isolated for treatment. Following treatment of the well
zone, the service tool is moved to a subsequent well zone isolated
for treatment. The active length of the service tool can be
adjusted according to the length of each well zone isolated for
treatment while maintaining a fluid return path in a desired
location for improving the well treatment operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Certain embodiments of the invention will hereafter be
described with reference to the accompanying drawings, wherein like
reference numerals denote like elements, and:
[0005] FIG. 1 is a front elevation view of a completion assembly
and service tool deployed in a wellbore, according to an embodiment
of the present invention;
[0006] FIG. 2 is an expanded, cross-sectional view of the service
tool positioned downhole at a well zone, according to an embodiment
of the present invention;
[0007] FIG. 3 is an illustration of a completion assembly and
service tool in which the active length of the service tool has
been adjusted to treat a well zone having a given length, according
to an embodiment of the present invention;
[0008] FIG. 4 is an illustration of a completion assembly and
service tool in which the active length of the service tool has
been adjusted to treat a subsequent well zone having a different
length, according to an embodiment of the present invention;
[0009] FIG. 5 is an illustration of a completion assembly and
service tool in which the active length of the service tool has
been adjusted to treat another subsequent well zone having a
different length, according to an embodiment of the present
invention;
[0010] FIG. 6 is a cross-sectional view of one of a plurality of
valves utilized in the service tool to open a selected return flow
path, according to an embodiment of the present invention;
[0011] FIG. 7 is a view similar to that of FIG. 6 but showing the
valve in a closed position, according to an embodiment of the
present invention;
[0012] FIG. 8 is a cross-sectional view of an alternate embodiment
of a valve having a lock able to maintain the valve in an open
position until valve closure is desired, according to another
embodiment of the present invention;
[0013] FIG. 9 is a view similar to that of FIG. 8 showing the valve
locked in an open position, according to an embodiment of the
present invention;
[0014] FIG. 10 is a view similar to that of FIG. 8 showing the
valve returned to a closed position, according to an embodiment of
the present invention;
[0015] FIG. 11 is another embodiment of a valve that can be
actuated by an internal pressure within the service tool, according
to an alternate embodiment of the present invention;
[0016] FIG. 12 is a view similar to that of FIG. 11 but showing the
valve progressing from a closed positioned to an open position,
according to an embodiment of the present invention;
[0017] FIG. 13 is a view similar to that of FIG. 11 showing the
valve in an open position, according to an embodiment of the
present invention;
[0018] FIG. 14 is a view similar to that of FIG. 11 showing the
valve returned to a closed position after breaking the seal with a
surrounding seal bore, according to an embodiment of the present
invention;
[0019] FIG. 15 is another embodiment of a valve that can be
actuated by a magnetic force, according to an alternate embodiment
of the present invention;
[0020] FIG. 16 is a view of an in-line valve in an open position to
permit flow through a bottom opening of the service tool, according
to an embodiment of the present invention;
[0021] FIG. 17 is a view similar to that of FIG. 16 showing the
in-line valve in a closed position, according to an embodiment of
the present invention;
[0022] FIG. 18 is another embodiment of an in-line valve having a
ball valve rotated to an open position, according to another
embodiment of the present invention; and
[0023] FIG. 19 is a view similar to that of FIG. 18 showing the
in-line ball valve in a closed position, according to an embodiment
of the present invention.
DETAILED DESCRIPTION
[0024] In the following description, numerous details are set forth
to provide an understanding of the present invention. However, it
will be understood by those of ordinary skill in the art that the
present invention may be practiced without these details and that
numerous variations or modifications from the described embodiments
may be possible.
[0025] The present invention generally relates to a well system
that can be used for well treatment operations, such as sand
control operations. The well system is designed to treat multiple
well zones in a single trip downhole. Generally, the well system
comprises a completion assembly and a service tool which can be
moved from one well zone to another to perform a treatment
operation at each well zone. Packers are used to isolate the well
zones to be treated. The well system is adaptable for use in a
variety of wells and with a variety of well zones. For example, the
active or effective length of the service tool can be changed to
accommodate well zones of dissimilar lengths while enabling a
bottom-of-zone clean fluid return path.
[0026] In one embodiment, the well system utilizes a service tool
in the form of a washpipe that provides multiple selected entry
points into and out of the washpipe. The service tool also enables
selective zone isolation via a plurality of selectively actuatable
valves within the washpipe that are able to seal inside the seal
bores within isolation packers deployed between well zones. In this
particular example, the valves are positioned along the wash pipe
such that each well zone length encountered in the well relates to
a corresponding valve within the service tool. The valves may be
biased to a closed position until actuated to an open position when
positioned near or inside the isolation packers. The valves above
and/or below the lower isolation packer defining a well zone remain
closed.
[0027] Referring generally to FIG. 1, one embodiment of a well
system 30 is illustrated. In this embodiment, well system 30
comprises a completion assembly 32 and a service string 34 deployed
in a wellbore 36. The wellbore 36 is drilled into a subsurface
formation 38 having a plurality of well zones 40 that may contain
desirable production fluids, such as petroleum. In the example
illustrated, wellbore 36 is lined with a casing 42. The casing 42
typically is perforated in a manner that places perforations 44
along each well zone 40. The perforations 44 enable flow of fluids
into (or out of) wellbore 36 at each well zone 40.
[0028] In the embodiment illustrated, completion assembly 32
comprises a tubular member 46 having screens 48 positioned at each
well zone 40 to allow fluid flow therethrough. For example, screens
48 allow the inward flow of returning treatment fluid from the
annulus surrounding the completion assembly 32 into the region
between tubular member 46 and service string 34 at the subject
treatment zone. A packer 50, such as a GP packer, secures
completion assembly 32 to wellbore casing 42. Additionally, a
plurality of isolation packers 52 are positioned between completion
assembly 32 and the surrounding casing 42 at selected locations to
selectively isolate the well zones 40. On an interior of tubular
member 46 proximate each isolation packer 52 is positioned a bore
region 54, e.g. a polished bore receptacle, for selective formation
of seals with service string 34, as discussed in greater detail
below.
[0029] Service string 34 is deployed downhole with completion
assembly 32 on an appropriate conveyance 56, such as a tubing. The
service string 34 may be attached to completion assembly 32
proximate the upper packer 50. Generally, service string 34
comprises an upper section 58 coupled to a service tool 60, e.g. a
washpipe, through a crossover 62. Crossover 62 comprises one or
more crossover exit ports 64 that are positioned adjacent
corresponding circulating ports of completion assembly 32 to enable
the flow of treatment fluid into the annulus surrounding completion
assembly 32. In a sand control operation, for example, a slurry may
be pumped down into this annulus at a given well zone, and a return
fluid or liquid portion of the slurry is returned up through
service string 34. In many applications, it is desirable for this
return fluid to reenter the service string 34 at a lower end of the
well zone being treated.
[0030] Service tool 60 is designed so that its active or effective
length can be changed to accommodate well zones of dissimilar
lengths. In the embodiment illustrated, the effective length of
service tool 60 can be changed while maintaining an entry port 66,
for any return fluid entering service tool 60, proximate a lower
end of the well zone 40 being treated. The effective length of
service tool 60 can be adjusted by a service tool length altering
mechanism 68. By way of example, the length altering mechanism 68
may comprise a plurality of valves 70 arranged along at least a
portion of the length of service tool 60. The valves 70 can each
engage the seal bore 54 to form a seal at the lower end of a well
zone 40 to be treated. Each valve 70 also can be individually
actuated to selectively open its entry port 66, thereby allowing
flow of fluid into the service tool at a lower end of the well
zone. The length of each well zone 40 to be treated dictates which
of the valves 70 engages/seals with bore region 54 proximate the
corresponding lower isolation packer 52. The other valves 70,
whether above or below this isolation packer 52, remain biased to a
closed position. The service tool 60 can be sealed at its upper end
by appropriate seal members 71 positioned around crossover 62 or at
the upper end of service tool 60.
[0031] Service tool 60 also may comprise an open bottom end 72. The
open bottom end 72 may be plugged with a ball or other blanking
device 74 during the treatment operation. As discussed in greater
detail below, linear fluid flow through service tool 60 also may be
selectively opened or closed by appropriate in-line valves.
[0032] In some well treatment operations, each well zone 40 is
sequentially treated. A well treatment fluid is flowed downhole as
indicated by arrows 76. The well treatment fluid exits the service
string at crossover 62 via crossover exit ports 64. The fluid flows
into the surrounding annulus between completion assembly 32 and
casing 42 at the well zone being treated. The return fluid then
reenters completion assembly 32 via the screen 48 positioned at
that particular well zone. The return fluid reenters service string
34 at the entry port 66 which has been opened proximate the lower
isolation packer 52 via actuation of the valve 70 engaged with the
corresponding seal bore 54. The fluid is then returned upwardly
along appropriate flow paths through service string 34.
[0033] The actual components and procedure for carrying out a given
multizone well treatment operation can vary. However, one example
comprises initially running a perforation assembly in-hole and
perforating each of the well zones 40. Subsequently, completion
assembly 32, along with service string 34, is run-in-hole. The
service string 34 can be attached to completion assembly 32 at the
upper packer. Once the completion assembly is placed on depth, open
bottom end 72 is blocked by, for example, dropping the ball or
other blanking device from the surface to make service string 34
pressure competent. Pressure is then applied into service string 34
to set the GP packer and secure completion assembly 32 to the
wellbore casing 42. The isolation packers are then set by an
appropriate packer setting procedure, e.g. by applying tubing
pressure with the service string in a packer setting position.
[0034] Additionally, the appropriate valve 70 is placed in sealing
engagement with the appropriate bore region 54, e.g. a seal bore,
at a lower end of the zone to be treated. The service string 34 is
placed in a circulating position in which exit port 64 is
positioned adjacent the circulating port of completion assembly 32.
The return or entry port 66 at the lower end of the zone to be
treated is actuated to an open position to enable circulation of
the treatment fluid. Upon completion of the treatment, the valve 70
is disengaged from bore region 54, and service tool 60 is moved to
the next well zone to be treated.
[0035] Referring generally to FIG. 2, one embodiment of service
tool length altering mechanism 68 is illustrated. In this
embodiment, mechanism 68 comprises a plurality of valves 70, e.g.
three valves, positioned at unique locations along the tubing or
wash pipe 78 of service tool 60. The illustrated valves 70 are
pressure actuated valves that are actuated to an open flow position
by application of a differential pressure once a particular valve
70 engages and seals with bore region 54. The differential pressure
is created between the pressure of the treatment fluid above
(uphole) of the sealed valve 70 and the pressure in the next
sequential, e.g. next lower, well zone. The valves 70 that are not
sealed with bore region 54 do not get exposed to this differential
pressure and remain biased to a closed position. Accordingly, the
linearly spaced valves 70 can accommodate well zones 40 of
different lengths while maintaining the fluid reentry port 66
proximate the lower isolation packer 52 at the lower end of the
well zone.
[0036] The ability to accommodate multiple well zones of dissimilar
lengths is illustrated in FIGS. 3-5 which show service tool 60
positioned at three different well zones of three different
lengths. In FIG. 3, for example, a lower well zone 40 is initially
treated. The lower well zone 40 is relatively short in length so
service tool 60 is moved into the well zone 40 until the upper
valve 70 forms a seal with the bore region 54 proximate the
isolation packer 52 at the lower and of this well zone. The
proximate seal can be located, for example, radially within the
isolation packer or slightly linearly offset of the isolation
packer. The valves 70 below the valve sealed against bore region 54
remain biased to the closed position. The closed valves 70 make the
effective length of service tool 60 relatively short to correspond
with the length of the lower well zone.
[0037] In FIG. 4, the service tool 60 has been moved to a
subsequent well zone 40 above the lower well zone that was
initially treated. This subsequent well zone 40 has a greater
length than the first well zone treated, and service tool 60 has
been moved into this subsequent well zone until the middle valve 70
forms a seal with the bore region 54 at the lower end of the zone.
The valves 70 that are above and below the sealed valve remain
biased to the closed position. This causes the effective length of
service tool 60 to be of an intermediate length that corresponds
with the length of the second or subsequent well zone being
treated.
[0038] In this example, the third well zone treated is above the
second well zone, as illustrated in FIG. 5. FIG. 5 illustrates
service tool 60 positioned in the third zone which has a greater
length than both the first and second zones treated. The service
tool has been moved into this third zone until the lower valve 70
forms a seal with the bore region 54 at the lower end of this third
well zone. The valves 70 that are above the sealed valve remain
biased to the closed position. This causes the effective length of
service tool 60 to be longer than with either of the first two
zones treated. Because each valve 70 opens its own entry port 66,
the fluid reentry point remains at the lower end of the well zone
during treatment of any of these well zones regardless of the well
zone length.
[0039] One embodiment of valve 70 is illustrated in FIGS. 6 and 7.
In this embodiment, valves 70 is actuated by a pressure
differential between the well treatment fluid above the valve
forming a seal with seal bore 54 and the adjacent zone below the
well zone being treated. In FIG. 6, the valve 70 has been shifted
or actuated to an open position in which entry port 66 is open to
admit flow into service tool 60. Valve 70 comprises a closure
member 80, such as a sleeve, connected to a piston 82.
Additionally, a seal member 84 is associated with the valve 70 and
is positioned to form a seal between bore region 54 and valve 70
when valve 70 is moved into the bore region. By way of example,
each seal member 84 is mounted along the exterior of a
corresponding valve 70, however the seal members also can be
mounted in corresponding bore regions 54. Piston 82 is biased
toward a closed position by a spring 86. However, once seal member
84 seals between seal region 54 and valve 70, piston 82 also is
acted on by the pressure of well treatment fluid on an uphole side
and by the pressure of the next lower well zone on a downhole side.
When the pressure differential between these two regions reaches a
sufficient level, the bias of spring 86 is overcome and valve 70 is
shifted to an open position, as illustrated in FIG. 6. When the
pressure differential is sufficiently reduced or eliminated, e.g.
by moving seal member 84 off bore region 54, spring 86 once again
biases the valve 70 to a closed position, as illustrated in FIG.
7.
[0040] An alternate embodiment of valve 70 is illustrated in FIGS.
8-10. In this alternate embodiment, the valve 70 is again actuated
by a sufficient pressure differential, but the valve includes a
lock which maintains the valve in an open position until the seal
member 84 is disengaged from its seal between valve 70 and the
surrounding bore region 54. The valve illustrated in FIGS. 8-10 is
similar in operation and has many similar components to the valve
described with reference to FIGS. 6 and 7. Similar components have
been labeled with the same reference numerals. In FIG. 8, valve 70
is biased to a closed position by spring 86 and flow through entry
port or ports 66 is blocked by closure member 80.
[0041] When a sufficient differential pressure is created between
the well treatment fluid on the treated zone side and the next
adjacent well zone on an opposite side of valve 70, valve 70 is
moved to an open position as illustrated in FIG. 9. Specifically,
the pressure of the well treatment fluid acts against piston 82 and
the bias of spring 86. Any fluid trapped by piston 82 in a sealed
region 88 (see FIG. 8) is forced along the piston 82 and discharged
radially outwardly through a check valve 90 to the next adjacent
well zone. The check valve 90 prevents the flow of fluid back into
sealed region 88 and thus holds piston 82 and closure member 80 in
the open position illustrated in FIG. 9 even if the pressure
differential is reduced or eliminated. Sealed region 88 also is in
fluid communication with a second port 92, however second port 92
is blocked from receiving any external fluid flow while seal member
84 is sealingly engaged between valve 70 and bore region 54. In the
embodiment illustrated, seal member 84 is mounted on valve 70 and
second port 92 extends to a region within seal member 84. Second
port 92 is blocked from receiving fluid flow while seal member 84
engages bore region 54, e.g. a seal bore.
[0042] Accordingly, valve 70 can be unlocked or released from its
open position by moving valve 70 and its seal member 84 off seal
bore 54, as illustrated in FIG. 10. Once seal member 84 is moved
away from seat bore 54, second port 92 is open to allow fluid flow
radially inward through second port 92 and into sealed region 88.
Spring 86 is then able to bias piston 82 and closure member 80 to a
closed position blocking flow through entry ports 66, as
illustrated in FIG. 10.
[0043] Another embodiment of valve 70 is illustrated in FIGS.
11-14. In this embodiment, valve 70 is operated by internal
pressure within the washpipe when the valve is located within one
of the bore regions 54. As illustrated in FIG. 11, this embodiment
of valve 70 comprises of valve section 94 and a primer section 96.
The valve section 94 comprises a piston 98 mounted on a piston
sleeve 100. Piston sleeve 100 includes a closure member 102 and a
port 104. Piston 98 and piston sleeve 100 are biased toward a
closed position, as illustrated in FIG. 11, by a spring 106. A
secondary piston 108 is slidably mounted around piston sleeve 100
between piston 98 and primer section 96.
[0044] Primer section 96 comprises a piston member 110 biased
toward a non-actuated position by a spring 112. When in the
non-actuated position, piston member 110 creates a cavity 114
filled with an incompressible fluid 116, which may be well fluid.
As pressure is increased within an interior 118 of the service tool
60, piston member 110 is shifted and fluid 116 is forced through a
check valve 120 and ultimately into a cavity 122 surrounding piston
sleeve 100 between secondary piston 108 and primer section 96.
Movement of incompressible fluid 116 into cavity 122 forces
secondary piston 108 to move toward piston 98, as illustrated in
FIG. 12. A cavity 124 located between piston 98 and secondary
piston 108 is filled with a compressible fluid 126 which is
compressed as secondary piston 108 moves toward piston 98.
Compressible fluid 126 acts as a spring which, when sufficiently
compressed, overcomes spring 106 and moves piston 98 and piston
sleeve 100 toward an open position. Ultimately, piston sleeve 100
is fully shifted to an open position and port 104 is aligned with
entry port 66 to enable flow of well treatment fluid into the
valve, as illustrated in FIG. 13.
[0045] Check valve 120 holds incompressible fluid 116 in cavity 122
and maintains valve 70 in an open position even if the internal
pressure is lowered. In the embodiment illustrated, a check valve
128 allows fluid from the well zone adjacent the well zone being
treated to once again flow into cavity 114. This enables spring 112
to move piston member 110 back to the non-actuated position, as
illustrated in FIG. 13. In this embodiment, the overall valve 70 is
actuated to an open position when the pressure differential between
the internal pressure and the pressure of the adjacent zone is
sufficient to initiate actuation of primer section 96. The valve 70
can be returned to its closed position by moving seal member 84 off
bore region 54 which allows the incompressible fluid trapped in
cavity 122 to flow outwardly through port 92, as illustrated in
FIG. 14. Spring 106 is then able to bias piston 98 and piston
sleeve 100 to the closed position.
[0046] As illustrated in FIG. 15, valve 70 also may be constructed
for actuation between a closed and open position without creation
of pressure differentials. In the embodiment illustrated, valve 70
is magnetically operated by creation of a magnetic force via a
magnetic component 130 located in the completion string near the
isolation packer 52. As the valve 70 is moved through the isolation
packer 52 and seal element 84 engages bore region 54, the magnetic
component 130 acts against a magnetic piston 132. The magnetic
force acting against magnetic piston 132 is sufficient to compress
a spring 134 and to open the valve 70, as illustrated in FIG. 15.
Spring 134 normally biases the valve toward a closed position. The
magnetic component can be located to open valve 70 before or after
the seal is formed between valve 70 and bore region 54. The timing
of the valve opening relative to formation of the seal also can be
adjusted for certain other types of valves, such as mechanically
actuated valves.
[0047] One or more of the washpipe valves 70 also can be coupled
with an in-line valve 136, as illustrated in FIGS. 16-19. The
in-line valve 136 can be used to isolate a bottom portion of the
service tool 60 and can be constructed in a variety of
configurations. For example, FIGS. 16 and 17 illustrate an
embodiment of in-line valve 136 that uses a one-way valve, e.g. a
check valve, 138 that seals against a seat 140 to prevent flow to
the section of the washpipe below the corresponding valve 70. When
valve 70 is biased to its closed position, one-way valve 138 is
open, as illustrated in FIG. 16, and fluid is free to flow through
check valve ports 142. However, when valve 70 is shifted to an open
position, one-way valve 138 seats against seat 140 and prevents
flow into the lower section of the service tool, as illustrated in
FIG. 17.
[0048] Another embodiment of in-line valve 136 is illustrated in
FIGS. 18 and 19. In this embodiment, in-line valve 136 uses a
two-way valve, e.g. a ball valve, 144 that can be moved along a
seat 146 to selectively allow and prevent flow to the section of
the washpipe below the corresponding valve 70. When valve 70 is
biased to its closed position, two-way valve 144 is open, as
illustrated in FIG. 18, and fluid is free to flow through to the
lower section of the service tool. However, when valve 70 is
shifted to an open position, two-way valve 144 is rotated to a
closed position via a linkage 148, as illustrated in FIG. 19.
[0049] The unique service tool 60 can be used in a variety of well
treatment applications. One example is a sand control application
in which a gravel slurry is circulated into the desired treatment
zone 40 through the crossover exit port 64 and corresponding
circulating port. Gravel is placed in the well zone and dehydrated
from the bottom up. The return fluid passes through the
corresponding screen 48 and into the annulus between screen 48 and
service tool 60. The return fluid flows into the entry port 66 at
the lower end of the well zone and is directed upwardly into the
wellbore annulus above service tool 60. As in other gravel packing
operations, the service tool is moved to a reverse position when
screenout is achieved. Pressure applied in the wellbore annulus
forces the slurry that remains in the tubing uphole to the surface.
The service tool 60 is then moved to the next well zone and the
operation is repeated. The plurality of valves 70 enables
optimization of the sand control treatment or other well treatment
by enabling adjustment of the length of the service tool to
correspond with the length of the subsequent well zone. Even when
the length of the service tool is adjusted, the return fluid port
66 is maintained at the lower end of the treated well zone.
[0050] The embodiments described above provide examples of well
treatment systems that can be used to perform sand control
treatments as well as other well treatments. The configuration of
the completion assembly and service string can be changed according
to requirements of a given treatment operation. Other components
can be added, removed or interchanged to facilitate the treatment
operation. For example, a variety of valves 70 can be used,
including pressure actuated valves, magnetically actuated valves,
mechanically actuated valves, and other valves that are capable of
enabling the effective length of the service tool to be adjusted.
Other components, such as a service string position indicator, can
be added to further facilitate the operation. Additionally, the
isolation of zones and the placement of the isolation packers can
be adjusted according to parameters of the well. Furthermore, the
present system and methodology can be utilized in both cased hole
applications and open hole applications.
[0051] Accordingly, although only a few embodiments of the present
invention have been described in detail above, those of ordinary
skill in the art will readily appreciate that many modifications
are possible without materially departing from the teachings of
this invention. Such modifications are intended to be included
within the scope of this invention as defined in the claims.
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