U.S. patent application number 09/839683 was filed with the patent office on 2001-11-29 for full bore set down tool assembly for gravel packing a well.
Invention is credited to Anyan, Steven L., Bissonnette, Harold Steven, Foster, Michael J..
Application Number | 20010045281 09/839683 |
Document ID | / |
Family ID | 23170048 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010045281 |
Kind Code |
A1 |
Foster, Michael J. ; et
al. |
November 29, 2001 |
Full bore set down tool assembly for gravel packing a well
Abstract
A full bore set down tool assembly provides a housing attached
to a packer in a wellbore and aligned with the production zone. A
service tool of the tool assembly is attached to a tubing string
extending to the surface and is adapted for selective, removable
attachment to and positioning within the housing. The tool assembly
defines a downstream flow path and a return flow path when the
service tool is attached to the housing. A ball valve that is
selectively shiftable from the surface opens and closes the return
flow path to define a circulate position and a squeeze position.
The housing, service tool, and ball valve also define a reverse
position. The tool assembly facilitates gravel packing of the
annulus between the wellbore casing and the service string
including the tool assembly.
Inventors: |
Foster, Michael J.;
(Houston, TX) ; Anyan, Steven L.; (Sugar Land,
TX) ; Bissonnette, Harold Steven; (Lafayette,
LA) |
Correspondence
Address: |
Patent Counsel
Schlumberger Technology Corporation
14910 Airline
P.O. Box 1590
Rosharon
TX
77583-1590
US
|
Family ID: |
23170048 |
Appl. No.: |
09/839683 |
Filed: |
April 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09839683 |
Apr 20, 2001 |
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09302974 |
Apr 30, 1999 |
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6220353 |
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Current U.S.
Class: |
166/278 ;
166/51 |
Current CPC
Class: |
E21B 2200/04 20200501;
E21B 43/04 20130101; E21B 34/12 20130101 |
Class at
Publication: |
166/278 ;
166/51 |
International
Class: |
E21B 043/04 |
Claims
I claim:
1. A tool assembly for use in a tool string for gravel packing an
annular area of a wellbore surrounding at least a portion of the
tool string in the wellbore, the tool assembly comprising: a
packer; a housing attached to the packer, the housing defining a
bore therethrough and further defining at least one orifice
providing communication between an exterior of the housing and the
bore; a service tool selectively attachable to a tubing string and
adapted for selective positioning within the housing; a selectively
shiftable ball valve mounted within the service tool, the ball
valve selectively, remotely shiftable between an open position and
a closed position; the service tool defining at least two alternate
flow paths; and the ball valve adapted and positioned to
selectively open and close at least one of the at least two
alternate flow paths.
2. The tool assembly of claim 1, further comprising: a downstream
flow path of the at least two alternate flow paths; a return path
of the at least two alternate flow paths; and the ball valve
positioned in the return flow path.
3. The tool assembly of claim 1, further comprising: the housing,
the service tool, and the ball valve defining and shiftable between
at least a squeeze position and a circulating position.
4. The tool assembly of claim 3, further comprising: the housing,
the service tool, and the ball valve also defining and shiftable
between a reverse position.
5. The tool assembly of claim 1, further comprising: an attachment
member adapted for selective releasable attachment of the service
tool to the housing.
6. The tool assembly of claim 5, wherein the attachment member
further comprises: a collar attached to the housing; a collet
attached to the service tool; the collar and the collet adapted for
cooperative, releasable mating attachment.
7. The tool assembly of claim 5, further comprising: the housing,
the service tool, and the ball valve defining and shiftable between
at least a squeeze position and a circulating position. the
attachment member adapted to attach the service tool to the housing
when the housing, the service tool, and the ball valve are in the
squeeze position and the circulating position.
8. The tool assembly of claim 1, further comprising: the ball valve
defining a valve passageway therethrough when the ball valve is in
the open position; the service tool defining a service tool bore
therethrough, the service tool bore comprising at least a portion
of one of the at least two alternate flow paths; and the diameter
of the valve passageway substantially equal to the diameter of the
service tool bore.
9. The tool assembly of claim 8, further comprising: the service
tool bore and the valve passageway sized and adapted to permit
passage of a well tool therethrough.
10. A tool assembly for use in a tool string for gravel packing an
annular area of a wellbore surrounding at least a portion of the
tool string in the wellbore, the tool assembly comprising: a
housing assembly defining a first flow path and a second flow path;
a ball valve of the housing assembly adapted to selectively open
and close one of the first and second flow paths; and the first and
second flow paths adapted to provide fluid communication of a
gravel pack material and a return fluid.
11. The tool assembly of claim 10, further comprising: the ball
valve defining a valve passageway therethrough when the ball valve
is in an open position; the diameter of the valve passageway is
about equal to the diameter of the associated one of the first and
second flow paths within which the ball valve is positioned.
12. A gravel pack assembly for use in a tool string for gravel
packing an annular area of a wellbore surrounding at least a
portion of the tool string in the wellbore, the assembly
comprising: a packer; a housing having a first end and a second
end, the housing defining a bore therethrough and at least one
orifice providing fluid communication between an exterior of the
housing and the bore; the housing attached to the packer proximal
the first end of the housing a sand screen adapted to allow the
flow of fluids therethrough in fluid communication with the
housing, the sand screen positioned below the second end of the
housing; a service tool selectively attachable to and positionable
within the housing, the service tool defining a downstream flow
path and a return flow path; the downstream flow path communicating
with the bore of the housing when the service tool is positioned
therein; the return path communicating with the sand screen; the
service tool having a valve in the return flow path, the valve
adapted to selectively open and close the return flow path to
control the flow of fluid therethrough; and the valve adapted to
control the flow through the return flow path.
13. The gravel pack assembly of claim 12, further comprising: the
diameter of the opening through the valve when the valve is open is
substantially equal to the diameter of the bore so that the valve
is adapted to provide access therethrough without substantially
reducing the cross sectional area and diameter of the bore.
14. The gravel pack assembly of claim 12, further comprising: the
service tool, the housing, and the ball valve defining at least a
squeeze position and a circulating position when the service tool
is attached to the housing.
15. The gravel pack assembly of claim 14, further comprising: the
service tool and the housing adapted to support compressive loading
when attached.
16. The gravel pack assembly of claim 12, further comprising: the
service tool, the housing, and the ball valve defining at least a
reverse position when the service tool is detached from the
housing.
17. A tool assembly for performing a gravel pack, the tool assembly
comprising: a service tool adapted for selective, attachment to a
service string; the service tool defining a downstream flow path
and a return path therethrough; a valve within the return path
selectively moveable between an open position and a closed position
and adapted to control the flow through the return path; and the
valve adapted to provide a full bore opening therethrough when in
the open position.
18. A gravel pack assembly, comprising: a housing attached to the
packer, the housing defining a bore therethrough; a service tool
adapted for selective, removable mating with the housing; an
attachment member adapted for selective, releasable attachment of
the service tool and the housing; the service tool selectively
shiftable between at least a circulating position and a squeeze
position; the attachment member engaged to attach the service tool
to the housing when the service tool is in the circulating position
and the squeeze position.
19. A method of gravel packing a well using a tool assembly
defining at least a downstream flow path and a return flow path and
having a ball valve in the return path, the method comprising:
positioning the tool assembly in the well; and selectively shifting
the tool assembly between at least a circulate position and a
squeeze position to perform the gravel pack, and actuating the ball
valve to a open position in the circulating position and a closed
position in the squeeze position.
20. A tool assembly for performing a gravel pack, the tool assembly
comprising: a tool assembly body; means for directing fluid through
the tool assembly body to perform the gravel pack; means for
selectively blocking a return flow through the body to define at
least a squeeze position and a circulating position; means for
supporting a load on the tool assembly body when the tool assembly
body is in at least the squeeze position and the circulating
position.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The present invention relates to the field of well tools.
More specifically, the invention relates to a device and method for
gravel packing a well that also allows for perforating or
fracturing a well in a single trip and that allows full bore access
through the device and with weight set down on the device.
[0003] 2. Related Art
[0004] Techniques are well known in the oil and gas industry for
controlling sand migration into wells penetrating unconsolidated
formations by gravel packing the wells. Sand migration and collapse
of unconsolidated formations can result in decreased flow and
production, increased erosion of well components, and production of
well sand which is a hazardous waste requiring specialized handling
and disposal. Such gravel packing typically consists of depositing
a quantity, or "pack," of gravel around the exterior of a
perforated liner and screen, with the pack preferably extending
into the perforations in the unconsolidated formation. The gravel
pack then presents a barrier to the migration of the sand while
still allowing fluid to flow from the formation. In placing the
gravel pack, the gravel is carried into the well and into the
formation in the form of a slurry, with much of the carrier fluid
or workover fluid being returned to the surface, leaving the gravel
in the desired location.
[0005] Attempts have been made in the past to minimize the number
of trips of the tool string into the well. Each trip of the tool
string into a well takes an appreciable amount of time, and
therefore incurs significant costs in terms of rig and crew time.
As will be readily apparent, these costs are dramatically increased
if the tool string is tripped to a great depth in a well. Further,
previous devices allow for the use of perforating guns attached to
the bottom of the gravel pack tool assembly so that the perforating
and gravel pack may be completed in a single trip. The same is true
for fracturing equipment which may be attached to prior tool
assembles to facilitate fracturing and gravel packing in a single
trip.
[0006] One problem associated with prior designs relates to control
and positioning of the tool assembles. As fluid from the surface is
pumped through the tubing and into the well to complete the gravel
pack, the tubing tends to shrink due to the temperature
differential between the surface and the bottom of the wellbore
where the gravel pack is performed. Additionally, other factors may
contribute to or cause tubing shrinkage. The tubing shrinkage may
create uncertainty as to the positioning of the tool assembly in
relation to the packer, sand screen, and other gravel pack
components. Some tool assemblies rely on the position of the tool
assembly in relation to the fixed downhole components required for
the gravel pack to determine the function of and flow paths through
the tool assembly. Thus, uncertainty in the positioning of the tool
assembly may cause the tool assembly to inadvertently shift from
one operation to another. For example, the distance between a
circulate position and a squeeze position in one prior tool is only
about 18 inches. Shrinkage may move the tool from squeeze to
circulate changing the flow paths and operation of the tool.
Similarly, in operations performed from a floating platform, the
deck heave can change the position of the tool assembly causing
uncertainty in the tool assembly positioning. Accordingly, there is
a need for a gravel pack tool assembly that eliminates the
uncertainty associated with the positioning of the tool assembly
and the operating position of the tool assembly.
[0007] Another problem associated with prior tool assembles is that
they block or restrict the size of the bore through the tool
assembly. The restriction limits the ability to perform operations
below the tool assembly. For example, in a tool assembly that
includes the perforating equipment attached to the bottom of the
tool, the manner of actuating the perforating guns is limited. One
preferred manner of actuating the perforating guns is to drop a
detonation bar through the tubing into engagement with the
perforating guns to fire the guns. Typical tool assembles that
restrict or block the tubing do not allow a detonation bar to pass
therethrough. Thus, the use of a detonation bar in such an
operation is not possible. Consequently, despite the use of the
prior art features, there remains a need for a tool assembly that
provides for full bore diameter through the tool assembly to allow
for operations to be performed through the tool assembly, such as
logging operations, and/or to allow the passage of well tools, such
as wireline and slickline tools, logging tools, chemical cutters,
drop balls, detonation/drop bars, and the like, through the tool
assembly.
SUMMARY
[0008] To achieve such improvements, the present invention provides
a full bore, set down tool assembly that provides a full bore
diameter through the tool, in one preferred embodiment, and that is
set in a packer in the wellbore in constant compression when in at
least the circulate and squeeze positions to ensure the proper
positioning and operation of the tool assembly. In general, the
tool assembly incorporates a shiftable ball valve to alternate
between a circulate and squeeze positions. When in the open
position, the ball valve provides for full bore access through the
tool assembly and in the closed position substantially prevents
flow through the return path of the tool assembly to allow for a
squeeze or reverse operation.
[0009] One aspect of the present invention provides a tool assembly
for use in a tool string for gravel packing an annular area of a
wellbore surrounding at least a portion of the tool string in the
wellbore. The tool assembly includes a packer and a housing
attached to the packer. The housing defines a bore therethrough and
at least one orifice provides communication between an exterior of
the housing and the bore. A service tool of the tool assembly is
selectively attachable to a tubing string and is adapted for
selective positioning within the housing. A selectively shiftable
ball valve mounted within the service tool is selectively and
remotely shiftable between an open position and a closed position.
The service tool defines at least two alternate flow paths and the
ball valve is adapted and positioned to selectively open and close
at least one of the alternate flow paths.
[0010] The tool assembly also includes a downstream flow path of
the alternate flow paths and a return path of the alternate flow
paths with the ball valve positioned in the return flow path. The
housing, the service tool, and the ball valve define and are
shiftable between at least a squeeze position, a circulating
position, and a reverse position.
[0011] One aspect of the present invention includes an attachment
member adapted for selective releasable attachment of the service
tool to the housing. The attachment member includes a collar
attached to the housing and a collet attached to the service tool
with the collar and the collet adapted for cooperative, releasable
mating attachment. The housing, the service tool, and the ball
valve define and are shiftable between at least a squeeze position
and a circulating position and the attachment member is adapted to
attach the service tool to the housing when the housing, the
service tool, and the ball valve are in the squeeze position and
the circulating position.
[0012] In one preferred embodiment, the ball valve defines a valve
passageway therethrough when the ball valve is in the open
position. The service tool defines a service tool bore therethrough
that comprises at least a portion of one of the at least two
alternate flow paths. The diameter of the valve passageway is
substantially equal to the diameter of the service tool bore.
Further, the service tool bore and the valve passageway are sized
and adapted to permit passage of a well tool therethrough.
[0013] Another aspect of the present invention provides a tool
assembly for use in a tool string for gravel packing an annular
area of a wellbore surrounding at least a portion of the tool
string in the wellbore. The tool assembly includes a housing
assembly that defines a first flow path and a second flow path. A
ball valve of the housing assembly is adapted to selectively open
and close one of the first and second flow paths and the first and
second flow paths are adapted to provide fluid communication of a
gravel pack material and a return fluid. The ball valve defines a
valve passageway therethrough when the ball valve is in an open
position. Preferably, the diameter of the valve passageway is about
equal to the diameter of the associated one of the first and second
flow paths within which the ball valve is positioned.
[0014] Yet another aspect of the present invention provides a
gravel pack assembly for use in a tool string for gravel packing an
annular area of a wellbore surrounding at least a portion of the
tool string in the wellbore. The gravel pack assembly includes a
packer and a housing having a first end and a second end. The
housing defines a bore therethrough and at least one orifice that
provides fluid communication between an exterior of the housing and
the bore. The housing is attached to the packer proximal the first
end of the housing. Typically, a sand screen is attached to the
housing proximal the second end of the housing. The screen is
adapted to allow the flow of fluids therethrough. A service tool is
selectively attachable to and positionable within the housing and
defines a downstream flow path and a return flow path. The
downstream flow path communicates with the bore of the housing when
the service tool is positioned therein. The return path
communicates with the sand screen. The service tool has a valve in
the return flow path that is adapted to selectively open and close
the return flow path to control the flow of fluid therethrough. The
diameter of the opening through the valve when the valve is open is
substantially equal to the diameter of the bore so that the valve
is adapted to provide access therethrough without substantially
reducing the cross sectional area and diameter of the bore.
Further, the service tool, the housing, and the ball valve define
at least a squeeze position and a circulating position when the
service tool is attached to the housing. The service tool and the
housing are adapted to support compressive loading when attached.
When the service tool is detached from the housing, the service
tool, the housing, and the ball valve define at least a reverse
position.
[0015] Still yet another aspect of the present invention provides a
tool assembly for performing a gravel pack. The tool assembly
includes a service tool adapted for selective attachment to a
service string. The service tool defines a downstream flow path and
a return path therethrough. Also included is a valve within the
return path selectively moveable between an open position and a
closed position and adapted to control the flow through the return
path. The valve is adapted to provide a full bore opening
therethrough when in the open position.
[0016] Another selected embodiment comprises a housing attached to
the packer that defines a bore therethrough. A service tool is
adapted for selective, removable mating with the housing. An
attachment member is adapted for selective, releasable attachment
of the service tool and the housing. The service tool is
selectively shiftable between at least a circulating position and a
squeeze position; and the attachment member is engaged to attach
the service tool to the housing when the service tool is in the
circulating position and the squeeze position.
[0017] Another aspect of the present invention provides a method of
gravel packing a well using a tool assembly that defines at least a
downstream flow path and a return flow path and has a ball valve in
the return path. The method includes positioning the tool assembly
in the well and selectively shifting the tool assembly between at
least a circulate position and a squeeze position to perform the
gravel pack and actuating the ball valve to a open position in the
circulating position and a closed position in the squeeze
position.
[0018] Yet another aspect of the present invention provides a tool
assembly for performing a gravel pack that includes a tool assembly
body with means for directing fluid through the tool assembly body
to perform the gravel pack; means for selectively blocking a return
flow through the body to define at least a squeeze position and a
circulating position; and means for supporting a load on the tool
assembly body when the tool assembly body is in at least the
squeeze position and the circulating position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The manner in which these objectives and other desirable
characteristics can be obtained is explained in the following
description and attached drawings in which:
[0020] FIG. 1 is schematic view of a service string including the
present invention positioned in a well.
[0021] FIGS. 2A-D are a partial cross sectional, side elevational
of the present invention in the squeeze position.
[0022] FIG. 3 is a top view of the ball valve.
[0023] FIG. 4 is a schematic view of the j-slots in the squeeze
position.
[0024] FIGS. 5A-D are a partial cross sectional, side elevational
of an alternative embodiment of the present invention in the
squeeze position.
[0025] FIG. 6 is a schematic view of the j-slots in the squeeze
position.
[0026] FIGS. 7A-D are a partial cross sectional, side elevational
of the present invention in the circulate position.
[0027] FIG. 8 is a schematic view of the j-slots in the circulate
position.
[0028] FIGS. 9A-E are a partial cross sectional, side elevational
of the present invention in the return position.
[0029] FIG. 10 is a schematic view of the j-slots in the return
position.
[0030] It is to be noted, however, that the appended drawings
illustrate only typical embodiments of this invention and are
therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The present invention generally provides a full bore, set
down tool assembly that provides a full bore diameter through the
tool, in one preferred embodiment, and that is set in a packer in
the wellbore in constant compression when in at least the circulate
and squeeze positions to ensure the proper positioning and
operation of the tool assembly. In general, the tool assembly
incorporates a shiftable ball valve to alternate between a
circulate and squeeze positions. When in the open position, the
ball valve provides for full bore access through the tool assembly
and in the closed position substantially prevents flow through the
return path of the tool assembly to allow for a squeeze or reverse
operation.
[0032] FIG. 1 is a schematic view of a wellbore 1 having a service
string 3 therein. The service string 3 includes a perforating gun
aligned with the zone to be produced, a bottom packer 5, a sand
screen 6, a gravel pack tool assembly 10, and a tool assembly
packer 7. The service string 3 is supported by a tubing string 8
extending to the surface. In this embodiment, the perforating guns
fire perforating the production zone. Then, the service string 3 is
lowered to align the packers above and below the perforations and
the packers are set isolating the production zone and defining an
annulus area between the service string 3 and the casing 2. The
gravel pack is then performed and the zone produced. The present
invention is useful in such an operation as well as other
operations requiring a gravel pack, and is useful in operations
other than those requiring perforation and gravel packing in a
single trip.
[0033] A typical gravel pack operation includes three operations
(among others) referred to as the squeeze operation, the
circulating operation, and the reverse operation. In the squeeze
operation, the gravel slurry is forced out into the formation 4 by
pumping the slurry into the production zone while blocking the
return flow path 46. The absence of a return flow path 46 causes
the pressure to build and force the slurry into the formation 4.
When the void spaces within the formation 4 are "filled," the
pressure will rise quickly, referred to as "tip screen out." Upon
tip screen out, the next typical step is to perform a circulating
operation in which the gravel slurry is pumped into the annular
area 9 between the sand screen 6 and the casing 2. In the
circulating position, the return flow path 46 is open and the
return fluid is allowed to flow back to the surface. The sand
screen 6 holds the gravel material of the gravel slurry in the
annular area 9 but allows fluids to pass therethrough. Thus,
circulating the gravel slurry to the sand screen 6 deposits the
gravel material in the annular area 9. However, during the
circulating operation, when the deposited gravel material reaches
the top of the sand screen 6, the pressure will rise rapidly
indicating screen out and a full annulus. Note that an alternative
manner of operating the tool is to perform the squeeze operation
with the tool assembly 10 in the circulate position and with a
surface valve (not shown) closed to prevent return flow. Using this
method, the shift from the squeeze operation to the circulate
operation may be made by simply opening the surface valve and
without the need to shift the tool.
[0034] When the annulus is packed, the string may be pulled from
the wellbore 1. However, to prevent dropping of any gravel material
remaining in the service string 3 and the tubing 8 into the well
when pulling the string from the well, the gravel in the tubing 8
and service string 3 is reverse circulated to the surface before
the string is removed. This procedure of reverse circulating the
remaining gravel from the well is referred to as the reverse
operation. In general, the flow of fluid is reverse circulated
through the tubing 8 to pump the gravel remaining in the tubing
string 8 and service string 3 to the surface.
[0035] Generally, because bridging may occur when depositing the
gravel in the well creating gaps in the gravel pack, the squeeze
and/or circulating operations may be performed more than once for
each gravel pack operation. This is referred to as "restressing the
pack." The reverse operation may be performed before restressing
the packing or between the squeeze and circulate operations as
desired.
[0036] A tool assembly 10 facilitates the gravel pack operation. As
used herein, the terms squeeze position, circulating position, and
reverse position shall refer to a position of the tool assembly
corresponding to the squeeze operation, the circulating operation,
and the reverse operation respectively.
[0037] Also, for the purposes of this discussion, the terms "upper"
and "lower," "up hole" and "downhole," "up," "down," and "upwardly"
and "downwardly" are relative terms to indicate position and
direction of movement in easily recognized terms. Usually, these
terms are relative to a line drawn from an upmost position at the
surface to a point at the center of the earth, and would be
appropriate for use in relatively straight, vertical wellbores.
However, when the wellbore 1 is highly deviated, such as from about
60 degrees from vertical, or horizontal, these terms do not make
sense and therefore should not be taken as limitations. These terms
are only used for ease of understanding as an indication of what
the position or movement would be if taken within a vertical
wellbore 1.
[0038] FIGS. 2A-D are a cross sectional elevational view of one
preferred embodiment of the tool assembly 10 (also referred to as
the gravel pack assembly). The tool assembly 10 generally comprises
a housing 12 attached to a packer 7 and a service tool 14 adapted
for removable attachment to the housing 12. By shifting the service
tool 14 and controlling the relative positioning of the service
tool 14 to the housing 12, the tool assembly 10 is shiftable
between the squeeze, circulating, and reverse positions. When
viewed in combination, the housing 12 and service tool 14 are also
referred to herein as the housing assembly 16.
[0039] The housing 12 has an elongated tubular body defining a bore
20 therethrough. At least one orifice defined by the housing 12
extends through a side wall 24 of the housing 12 to provide fluid
communication between the bore 20 and an exterior 26 of the housing
12. A first end 28 of the housing 12, typically, the upper end, is
attached to, or proximal to, a packer 7. When set, the packer 7
maintains the position of the packer 7 and the housing 12 relative
to the production zone and prevents their movement within the
wellbore 1. Note that the packer 7 may define a portion of the
housing 12. Attached to a second, or bottom, end 30 of the housing
12 is the sand screen 6.
[0040] The service tool 14 has a generally cylindrical body sized
and adapted to fit within and mate with the bore 20 of the housing
12. The service tool 14 is adapted for selective, releasable
attachment to and positioning of at least a portion thereof within
the housing 12. A first, or upper, end 34 of the service tool 14 is
adapted for attachment to the tubing string 8 such as by threaded
connection, with the service tool bore 60 in fluid communication
with the tubing string 8. To facilitate the gravel pack operation,
the service tool 14 defines at least two alternate flow paths 38,
comprising at least first and second flow paths, 40 and 42
respectively. In general, one flow path, the downstream flow path
40, delivers the gravel pack material in the circulating and
squeeze operations; and the other, second flow path provides the
return path 42.
[0041] The alternate flow paths 38 are adapted to provide a live
annulus wherein the well annulus above the service tool packer 7
communicates with the formation while the service tool 14 is in
use. Thus, if pumping is halted, the operator can still monitor the
pressure below the packer 7. Prior systems do not provide a live
annulus.
[0042] The service tool 14 is releasably attachable to the housing
12 by an attachment member 48. In general, the attachment member 48
is adapted to temporarily attach the service tool 14 to the housing
12 and to support a load necessary to keep a compressive load on
the service tool 14. In the preferred embodiment shown in FIG. 1,
the service tool 14 is attached to the housing 12 with the
attachment member 48 engaged during the circulate and squeeze
operations. The service tool 14 is detached and the attachment
member 48 disengaged during the reverse operation. Attaching the
service tool 14 to the housing 12 during the squeeze and circulate
operations ensures that the tool assembly 10 is in the proper
position during the relevant operations and provides added
reliability. The relatively high load capacity of the attachment
member 48 allows the tool assembly 10 to operate with weight set
down on the tool assembly 10, further adding to the reliability of
the tool.
[0043] In one embodiment, the attachment member 48 comprises a
collar 50 attached to the housing 12 defining a profile 52 therein.
A collet 54 attached to the second, bottom end 36 of the service
tool 14 is adapted for releasable, cooperative mating with the
profile 52 of the collar 50. The spring force, or snap force, of
the collet 54 provides a resistance to upward movement and
detachment of the collet 54 from the collar 50 offering a
resistance to detachment and providing the operator with assurance
of proper relative positioning of the service tool 14 and the
housing 12. During shifting of the service tool 14, the collet 54
is pulled from the collar 50 and then, typically, forced back into
the collar 50. The resistance offered by the snap force of the
collet 54 provides a positive indication at the surface to the
operator that the tool 14 has shifted. Other similar attachments of
the service tool 14 to the housing 12 are readily apparent to those
skilled in the art and are, therefore, considered a part of the
scope of the present invention. Further, the attachment member 48,
in one alternative embodiment (not shown), is replaced with a
shoulder adapted to support the load requirements. In this
alternative embodiment, the service tool 14 is not "attached" to
the housing 12, but is maintained in the housing 12 by
substantially maintaining a downward force on the service tool
14.
[0044] The service tool 14 defines a service tool bore 60 extending
longitudinally therethrough. Service tool orifices 62 (at least
one) extend through the wall of the service tool 14 and provide
fluid communication between the service tool bore 60 and an
exterior 64 of the service tool 14. The service tool orifices 62
are positioned in the service tool 14 such that, when the service
tool 14 is positioned in and attached to the housing 12, so that
the tool assembly 10 is in the circulating or squeeze position, the
service tool orifice 62 communicates with an housing assembly
annulus 66 formed between the service tool 14 and the housing 12.
The housing orifices 22 are also positioned to communicate with the
housing assembly annulus 66. Seals 68 mounted above and below the
service tool orifice 62 and the housing orifices 22 seal the top
and bottom of the housing assembly annulus 66 between the service
tool 14 and the housing 12. Accordingly, the service tool orifices
62, the housing assembly annulus 66, and the housing orifices 22
provide a fluid communication passageway from the service tool bore
60 to the annular area 9 between the tool assembly 10 and the
casing 2 of the wellbore 1 when the tool assembly 10 is in the
circulating or squeeze positions. Thus, the service tool bore 60
and the service tool orifice 62 define a downstream flow path 40
through the service tool 14; the service tool bore 60, the service
tool orifice 62, the housing assembly annulus 66 and the housing
orifice 22 define a downstream flow path 40 through the housing
assembly 16 that provides communication between the tubing string 8
and the annulus formed between the service string 3 and the
wellbore 1 when the tool assembly 10 is in the circulating or
squeeze positions.
[0045] A plug 70 in the service tool 14 positioned below the
service tool orifices 62 prevents flow through the service tool
bore 60 beyond the plug 70. In alternative embodiments, the plug 70
is either fixed and integral with the body of the service tool 14
or is a removable plug 70 (FIGS. 5A-D) that is adapted for
selective insertion and placement within the service tool bore 60.
For example, in those embodiments that require a full open bore
through the tool assembly 10 to provide a passageway for a well
tool, such as a detonation/drop bar, a ball, a logging tool, a
wireline or slickline tool, a chemical cutter, and the like,
through the tool assembly 10, the insertable type plug 70 is
required. Using the insertable type plug 70, the well tool is
passed through the tool assembly 10 prior to inserting the plug 70.
The tool assembly 10 is then operated with the plug 70 in
place.
[0046] The service tool 14 further defines at least one, but
preferably a plurality of, return passageways 74 extending
longitudinally through the wall of the service tool 14. The inlets
76 to the return passageways 74 are positioned on a side of the
plug 70 opposite to the position of the service tool orifices 62 so
that the plug 70 prevents fluid communication between the service
tool orifices 62 and the return passageway 74 inlets 76 via the
service tool bore 60. Further, the return passageways 74 are offset
from the service tool orifices 62 in the wall of the service tool
14 to prevent communication therebetween. The outlets of the return
passageways 74 are positioned proximal the first, upper end of the
service tool 14 and communicate with an exterior 64 of the service
tool 14. Therefore, the return passageways 74 provide fluid
communication between the service tool bore 60 below the plug 70 to
the exterior 64 of the service tool 14 at a position proximal the
first, upper end of the service tool 14. The outlets 78 of the
return passageways 74 are positioned in the service tool 14 such
that when the tool assembly 10 is in the circulating or squeeze
position the outlets 78 are above the packer 7 providing
communication between the annulus formed between the tubing string
8 and the casing 2 and the service tool bore 60 below the plug 70.
The service tool bore 60 below the plug 70 and the return
passageways 74 are collectively referred to herein as the return
path 42.
[0047] A ball valve 80 (FIG. 3 is a top view of the ball valve 80)
of the service tool 14 is provided in the return path 42,
specifically in the service tool bore 60 below the plug 70 in one
preferred embodiment. The ball valve 80 is adapted to move between
an opened position and a closed position. In the closed position,
the ball valve 80 substantially seals the service tool bore 60
preventing flow through the return path 42. In the open position,
the ball valve 80 permits fluid flow therethrough and through the
return path 42. Further, in the preferred embodiment, the ball
valve 80 defines a valve passageway 82, when in the open position,
that has a diameter that is substantially about equal to the
diameter of the service tool bore 60 to provide full bore access
through the service tool 14. Thus, the service tool bore 60 and the
valve passageway 82 are sized and adapted to permit a well tool to
pass therethrough providing a full bore passageway through the tool
assembly 10. The ball valve 80, in one preferred embodiment,
includes an energized seal 84 (a spring loaded seal) to ensure
sealing between the ball and the service tool bore 60.
[0048] Note that, although the preferred embodiment is described as
a ball valve 80, the present invention may incorporate any type of
valve 80 that is capable of providing a valve passageway 82 capable
of providing a full open bore therethrough that does not
substantially reduce the cross sectional area of the bore through
the service tool 14 to allow passage of well tools through the tool
assembly 10.
[0049] A shifting mechanism 90 of the service tool 14 actuates the
ball valve 80 between the open and closed positions. An upper
portion 92 of the service tool 14 is free to move axially relative
to a lower portion 94 of the service tool 14 within a predefined
limited range. The relative axial movement is achieved when the
lower portion 94 is attached to the housing 12 by way of the
attachment mechanism. The upper portion 92 is then moved axially by
an operator controlling the position of the tubing string 8 from
the surface. Thus, the operator moves the tubing string 8 and,
thus, the upper portion 92 of the service tool 14 providing
relative movement between the upper and lower portions, 92 and 94,
actuating the shifting mechanism 90. Note that the snap force of
the collet 54 provides a positive indication that the tool 14 has
shifted.
[0050] The shifting mechanism 90 comprises a mandrel 96 positioned
in the service tool 14 such that it is free to spin relative to the
remainder of the service tool 14. The mandrel 96 has a series of
j-slots 98 (well know in the art) adapted to mate with a pin 100
fixed to lower portion 94 of the service tool 14. The j-slots 98
and pin 100 cooperate to produce a predetermined rotation (such as
45.degree.) of the mandrel 96 for each up or down cycle of the
upper portion 92 relative to the lower portion 94. FIGS. 4, 8, and
10 show the j-slots 98 and pin 100 positioned for the squeeze,
circulate, and reverse positions respectively. The shape,
positioning, and length of the j-slots 98 in cooperation with an
interconnected control lug member 102 and mating control lug
receiver 104 are adapted to selectively limit the allowable axial
movement of the upper portion 92 relative to the lower portion 94.
A yolk 106 attached to the mandrel 96 at one end is attached to the
ball valve 80 at the opposite end and is adapted to move axially
within the service tool 14. The movement of the mandrel 96 and the
control lug member 102 control the position of the yolk 106 to
selectively open and close the ball valve 80 in response to
relative movement of the upper portion 92 of the service tool 14 to
the lower portion 94. In one preferred embodiment, the valve 80 is
closed upon pickup and open upon every other set down of the
service tool 14.
[0051] In operation, the tool assembly 10 is typically run into the
wellbore 1 with the service tool 14 attached to the housing 12 and
the downstream flow path 40 providing a reference pressure with the
annulus and the tubing string 8. The tool assembly 10 may be run
into the wellbore 1 with the ball valve 80 in either the open or
closed position. Once in the proper position, the packers are set
and the housing 12 position is established.
[0052] As discussed, in general the first operation is the squeeze
operation (FIGS. 2A-D, 4, and 5A-D). In the squeeze operation, the
service tool 14 is attached to the housing 12 and the ball valve 80
is closed preventing flow through the return path 42. The gravel
slurry is pumped down through the tubing string 8 into the service
tool bore 60, through the downstream flow path 40, and into the
annulus between the service string 3 and the casing 2. The return
path 42 is blocked, therefore, the pressure builds forcing the
gravel slurry into the formation 4 until pressure rises rapidly
indicating "tip screen out."
[0053] Once tip screen out occurs, the tool assembly 10 is shifted
to the circulating position (FIGS. 7A-D and 8) by lifting and
lowering the tubing to move the upper portion 92 of the service
tool 14 the required number of times, as defined by the shifting
mechanism 90 (see FIG. 8 for the j-slot position), to shift the
service tool 14 and move the ball valve 80 to the open position
(FIG. 7C). During the shifting of the service tool 14, collet 54 of
the attachment member 48 is pulled from the collar 50 providing a
surface indication that the tool has shifted. Thus the snap force
of the collet 54 is selected to provide the desired surface
indication. The collet 54 is forced back into the collar 50 to
further shift the tool assembly 10. This shifting process is
repeated as necessary When in the open position the return path 42
is open. The gravel slurry is pumped through the tubing string 8 to
the service tool bore 60, through the downstream flow path 40, and
into the annulus between the service string 3 and the wellbore
casing 2 below the tool assembly packer 7 where the gravel material
is deposited. The return fluid flows through the sand screen 6,
into the service tool bore 60 through the second, lower end below
the plug 70, through the return path 42 of the service tool 14, and
into the annulus between the tubing string 8 and the casing 2 at a
point above the packer 7. The return fluid then flows to the
surface. Upon screen out, the circulating operation is stopped. The
squeeze and circulating operations may be repeated as needed by
simply shifting the service tool 14 as described to selectively
open and close the ball valve 80.
[0054] After the circulating and squeeze operations are complete,
the reverse operation is typically performed in preparation of
pulling the service string 3 from the wellbore 1. To position the
service tool 14 in the reverse position (FIGS. 9A-E and 10), the
tool assembly 10 is shifted by lifting the tubing to move the upper
portion 92 of the service tool 14, as defined by the shifting
mechanism 90 (see FIG. 10 for the j-slot position), to shift the
service tool 14 and move the ball valve 80 to the closed position
(in the preferred embodiment shown, the ball is closed upon pick-up
of the service tool 14). The attachment member 48 is then detached
releasing the service tool 14 from the housing 12 typically by
pulling up on the tubing string 8 with sufficient force to release
the actuating mechanism. Then, the service tool 14 is lifted from
the housing 12 to a position at which at least the service tool
orifices 62 are positioned above the packer 7. The well is reverse
circulated pumping "clean" fluid down through the annulus, through
the service tool orifices 62 into the service tool bore 60, up
through the service tool bore 60 into the tubing string 8, and
through the tubing string 8 to the surface. Any gravel slurry
remaining in the tubing string 8 and the service tool bore 60 is
forced to the surface with the exception possibly of a small amount
deposited between the service tool orifices 62 and the ball valve
80.
[0055] While the foregoing is directed to the preferred embodiment
of the present invention, other and further embodiments of the
invention may be devised without departing from the basic scope
thereof, and the scope thereof is determined by the claims which
follow. It is the express intention of the applicant not to invoke
35 U.S.C. .sctn. 112, paragraph 6 for any limitations of any of the
claims herein, except for those in which the claim expressly uses
the words "means for" together.
* * * * *