FLOW CONTROL SCREEN ASSEMBLY HAVING REMOTELY DISABLED
REVERSE FLOW CONTROL CAPABILITY
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates, in general, to equipment utilized in conjunction with
operations performed in subterranean wells and, in particular, to a flow control screen
assembly that is operable to control the inflow of formation fluids and selectively operable to
prevent reverse flow of fluids into the formation.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its background will be
described with reference to fluid production from a hydrocarbon bearing subterranean
formation, as an example.
[0003] During the completion of a well that traverses a hydrocarbon bearing
subterranean formation, production tubing and various completion equipment are installed in
the well to enable safe and efficient production of the formation fluids. For example, to
prevent the production of particulate material from an unconsolidated or loosely consolidated
subterranean formation, certain completions include one or more sand control screens
positioned proximate the desired production intervals. In other completions, to control the
flow rate of production fluids into the production tubing, it is common practice to install one
or more flow control devices within the tubing string.
[0004] Attempts have been made to utilize fluid flow control devices within
completions requiring sand control. For example, in certain sand control screens, after
production fluids flows through the filter medium, the fluids are directed into a flow control
section. The flow control section may include one or more flow restrictors such as flow
tubes, nozzles, labyrinths or the like. Typically, the production rate through these flow
control screens is fixed prior to installation by individually adjusting the flow restrictors of
the flow control screens.
[0005] It has been found, however, that the during the completion process, it may be
desirable to pressure up the completion string to operate or set certain tools, such as packers.
Current flow control screens require the running of a separate work string into the completion
string to achieve this result or require that one or more permanent check valves be
incorporated into each of the flow control screens.
desirable to allow reverse flow from the completion string into the formation in certain
completions requiring fluid flow control, sand control and tools setting capabilities.
[0006] Accordingly, a need has arisen for a flow control screen that is operable to
control the inflow of formation fluids in a completion requiring sand control. A need has also
arisen for such a flow control screen that is operable to be pressured up during the completion
process. Further, a need has arisen for such a flow control screen that is operable to
selectively allow reverse flow from the completion string into the formation.
SUMMARY OF THE INVENTION
[0007] The present invention disclosed herein comprises a flow control screen for
controlling the inflow of formation fluids in completions requiring sand control. In addition,
the flow control screen of the present invention is operable to be pressured up during the
completion process. Further, the flow control screen of the present invention is operable to
selectively allow reverse flow from the completion string into the formation.
[0008] In one aspect, the present invention is directed to a flow control screen having a
fluid flow path between an interior of a base pipe and a filter medium. The flow control
screen includes a valve assembly disposed within the fluid flow path. The valve assembly
includes a piston body, a valve plug and a ball retainer having an opening. The piston body
has an internal seat and a collet assembly that is radially outwardly constrained by the ball
retainer in a first operating position to retain the valve plug in the piston body and radially
outwardly unconstrained by the ball retainer in a second operating position. In operation, an
internal differential pressure seats the valve plug on the internal seat to prevent reverse flow,
a predetermined internal differential pressure on the valve plug causes the piston body to shift
from the first operating position to the second operating position while continuing to prevent
reverse flow and, in the second operating position, an external differential pressure causes the
valve plug to be expelled from the valve assembly through the opening of the ball retainer,
thereby no longer preventing reverse flow.
[0009] In one embodiment, at least a portion of the collet assembly is slidably
positioned within the ball retainer in the first operating position. In this embodiment,
operation of the piston assembly from the first operating position to the second operation
position is prevented by a retainer pin until the predetermined internal differential pressure
acts on the valve plug. In another embodiment, the valve plug is a spherical blocking
member. In certain embodiments, the collet assen
radially inwardly projecting lips, radially outwardly projecting lips or both.
[0010] In one embodiment, the valve assembly includes a reentry barrier operably
associated with the ball retainer to prevent reentry of the valve plug into the valve assembly.
In certain embodiments, the reentry barrier is in the form of a c-ring positioned around the
ball retainer. In some embodiments, the reentry barrier at least partially extends into the
opening of the ball retainer. In other embodiments, the reentry barrier resists exit of the valve
plug from the valve assembly.
[0011] In another aspect, the present invention is directed to a flow control screen
having a fluid flow path between an interior of a base pipe and a filter medium. The flow
control screen includes a plurality of circumferentially distributed valve assemblies disposed
within the fluid flow path. Each valve assembly includes a piston body, a valve plug and a
ball retainer having an opening. The piston body has an internal seat and a collet assembly
that is radially outwardly constrained by the ball retainer in a first operating position to retain
the valve plugs in the piston body and radially outwardly unconstrained by the ball retainer in
a second operating position. In operation, an internal differential pressure seats the valve
plugs on the internal seats to prevent reverse flow, a predetermined internal differential
pressure on the valve plugs causes the piston bodies to shift from the first operating position
to the second operating position while continuing to prevent reverse flow and, in the second
operating position, an external differential pressure causes the valve plugs to be expelled
from the valve assemblies through the openings of the ball retainers, thereby no longer
preventing reverse flow.
[0012] In a further aspect, the present invention is directed to a method for operating a
flow control screen. The method includes disposing at least one valve assembly within a
fluid flow path between an interior of a base pipe and a filter medium, retaining a valve plug
within a piston body of the valve assembly by radially outwardly constraining a collet
assembly in a first operating position of the piston body with a ball retainer, applying an
internal differential pressure to seat the valve plug on an internal seat of the piston body to
prevent reverse flow, applying a predetermined internal differential pressure on the valve
plug to shift the piston body from the first operating position to a second operating position
while continuing to prevent reverse flow and applying an external differential pressure to
expel the valve plug from the valve assembly through an opening in the ball retainer, thereby
no longer preventing reverse flow. The method may also include preventing reentry of the
valve plug into the valve assembly with a reentry
extending at least partially into the opening.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a more complete understanding of the features and advantages of the present
invention, reference is now made to the detailed description of the invention along with the
accompanying figures in which corresponding numerals in the different figures refer to
corresponding parts and in which:
[0014] Figure 1 is a schematic illustration of a well system operating a plurality of flow
control screens according to an embodiment of the present invention;
[0015] Figures 2A-2C are quarter sectional views of successive axial sections of a flow
control screen according to an embodiment of the present invention;
[0016] Figure 2D is a cross sectional view of the flow control screen of figure 2B taken
along line 2D-2D;
[0017] Figure 2E is a cross sectional view of the flow control screen of figure 2C taken
along line 2E-2E;
[0018] Figures 3A-3D are cross sectional views of a valve assembly in its various
operating configurations that is operable for use in a flow control screen according to an
embodiment of the present invention;
[0019] Figure 4 is an isometric view of a piston assembly of a valve assembly that is
operable for use in a flow control screen according to an embodiment of the present
invention; and
[0020] Figure 5 is an isometric view of a ball retainer having a reentry barrier of a valve
assembly that is operable for use in a flow control screen according to an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] While the making and using of various embodiments of the present invention
are discussed in detail below, it should be appreciated that the present invention provides
many applicable inventive concepts which can be embodied in a wide variety of specific
contexts. The specific embodiments discussed herein are merely illustrative of specific ways
to make and use the invention, and do not delimit the scope of the present invention.
[0022] Referring initially to figure 1, there
plurality of flow control screens embodying principles of the present invention that is
schematically illustrated and generally designated 10. In the illustrated embodiment, a
wellbore 12 extends through the various earth strata. Wellbore 12 has a substantially vertical
section 14, the upper portion of which has cemented therein a casing string 16. Wellbore 12
also has a substantially horizontal section 18 that extends through a hydrocarbon bearing
subterranean formation 20. As illustrated, substantially horizontal section 18 of wellbore 12
is open hole.
[0023] Positioned within wellbore 1 and extending from the surface is a tubing string
22. Tubing string 22 provides a conduit for formation fluids to travel from formation 20 to
the surface and injection fluids to travel from the surface to formation 20. At its lower end,
tubing string 22 is coupled to a completions string that has been installed in wellbore 12 and
divides the completion interval into various production intervals adjacent to formation 20.
The completion string includes a plurality of flow control screens 24, each of which is
positioned between a pair of packers 26 that provides a fluid seal between the completion
string and wellbore 12, thereby defining the production intervals.
[0024] Flow control screens 24 serve the primary functions of filtering particulate
matter out of the production fluid stream and controlling the flow rate of the production fluid
stream. In addition, as discussed in greater detail below, flow control screens 24 are operable
to be pressured up during installation of the completion string. For example, when the
completion string is positioned in the desired location in wellbore 12, internal pressure may
be used to set packers 26 to divide the completion interval into the desired number of
production intervals. During this setting process, flow control screens 24 are in their running
configuration in which they are operable to hold pressure for repeated cycles as long as the
pressure remains below a predetermined threshold pressure. Once all pressure operated
completion components are set or during the setting of the final pressure operated completion
component, the internal pressure may be raised above the predetermined threshold pressure to
operate flow control screens 24 into their sheared configuration. In this configuration, flow
control screens 24 continue to hold pressure, however, when the internal pressure is released
and the differential pressure across flow control screens 24 is positive between the outside
and inside of flow control screens 24, flow control screens 24 are operated to their production
configuration.
[0025] Even though figure 1 depicts the flow
an open hole environment, it should be understood by those skilled in the art that the flow
control screens of the present invention are equally well suited for use in cased wells. Also,
even though figure 1 depicts one flow control screen in each production interval, it should be
understood by those skilled in the art that any number of flow control screens of the present
invention may be deployed within a production interval without departing from the principles
of the present invention. In addition, even though figure 1 depicts the flow control screens of
the present invention in a horizontal section of the wellbore, it should be understood by those
skilled in the art that the flow control screens of the present invention are equally well suited
for use in well having other directional configurations including vertical wells, deviated well,
slanted wells, multilateral wells and the like. Accordingly, it should be understood by those
skilled in the art that the use of directional terms such as above, below, upper, lower, upward,
downward, left, right, uphole, downhole and the like are used in relation to the illustrative
embodiments as they are depicted in the figures, the upward direction being toward the top of
the corresponding figure and the downward direction being toward the bottom of the
corresponding figure, the uphole direction being toward the surface of the well and the
downhole direction being toward the toe of the well.
[0026] Referring next to figures 2A-2C, therein is depicted successive axial sections of
a flow control screen according to the present invention that is representatively illustrated and
generally designated 100. Flow control screen 100 may be suitably coupled to other similar
flow control screens, production packers, locating nipples, production tubulars or other
downhole tools to form a completions string as described above. Flow control screen 100
includes a base pipe 102 that has a blank pipe section 104 and a perforated section 106
including a plurality of production ports 108. Positioned around an uphole portion of blank
pipe section 104 is a screen element or filter medium 112, such as a wire wrap screen, a
woven wire mesh screen, a prepacked screen or the like, designed to allow fluids to flow
therethrough but prevent particulate matter of a predetermined size from flowing
therethrough. Positioned downhole of filter medium 112 is a screen interface housing 114
that forms an annulus 116 with base pipe 102. Securably connected to the downhole end of
screen interface housing 114 is a sleeve housing 118. At its downhole end, sleeve housing
118 is securably connected to a flow tube housing 120 which is securably connected to the
uphole end of an intermediate housing 122. In addition, flow tube housing 120 is preferably
securably connected or sealably coupled to base pipe 102 to prevent fluid flow therebetween.
Toward its downhole end, intermediate housing
assembly housing 124 which is preferably welded to base pipe 102 at its downhole end. The
various connections of the housing sections may be made in any suitable fashion including
welding, threading and the like as well as through the use of fasteners such as pins, set screws
and the like. Together, the housing sections create a generally annular fluid flow path
between filter medium 112 and perforated section 106 of base pipe 102.
[0027] Positioned in the annular region between housing sleeve 118 and base pipe 102
is a split ring spacer 126. Positioned within a plurality of axial openings 128 in flow tube
housing 120 are flow tubes 130 that form a fluid flow control section of flow control screen
100. As best seen in figure 2D, the illustrated embodiment includes six axial openings 128
and six flow tubes 130, however, those skilled in the art will recognize that other numbers of
flow tubes both greater than and less than six could alternatively be used and would be
considered within the scope of the present invention. Each of the flow tubes 130 is secured
within flow tube housing 120 by a threaded retaining sleeve 132. One or more of the flow
tube 130 may have a threaded cap or a plug 134 associated therewith to inhibit or stop flow
therethrough. The use of plugs 134 and flow tubes 130 having various inner lengths and
diameters allow an operator to adjust the pressure drop rating of each flow control screen 100
to a desired level such that a completion string including a plurality of flow control screens
100 is operable to counteract heel-toe effects in long horizontal completions, balance inflow
in highly deviated and fractured wells, reduce annular sand transportation and reduce
water/gas influx, thereby lengthening the productive life of the well.
[0028] Positioned within a plurality of axial openings 146 in valve assembly housing
124 are valve assemblies 136 that form a reverse fluid flow control section of flow control
screen 100. As best seen in figure 2E, the illustrated embodiment includes six axial openings
146 for six valve assemblies 136, however, those skilled in the art will recognize that other
numbers of valve assemblies both greater than and less than six could alternatively be used
and would be considered within the scope of the present invention.
[0029] As best seen in figures 3A-3D, each valve assembly 136 includes a piston
assembly 138, a valve plug 140, a retainer pin 142 and a ball retainer 144. Piston assembly
138 includes a piston body 148 having an o-ring groove 150, as best seen in figure 5.
Integrally extending from piston body 148 is a plurality of collet fingers 1 4 forming a collet
assembly 156. At the distal ends thereof, each collet finger 154 includes a lip 158. In the
illustrated embodiment, lip 158 include a radially inwardly portion and a radially outwardly
portion. As explained in greater detail below, co
radially outwardly constrained in a first operating position of piston body 148 to retain valve
plug 140 within piston body 148 and radially outwardly unconstrained in a second operating
position of piston body 148.
[0030] Valve plugs 140 are depicted as spherical blocking members and are initially
allowed to move within piston body 148 between shoulder 160 and lips 158, as best seen in
figure 3A. Those skilled in the art will recognize, however, that even though valve plugs 140
are depicted as spherical in shape, valve plugs 140 could have alternate shapes including
cylindrical configurations, substantially cylindrical configurations or other configurations so
long as valve plugs 140 are capable of creating a seal within piston body 148 and of being
ejected from piston body 148, as described below. As illustrated, uphole travel of each valve
plug 140 is limited by shoulder 160 and downhole travel of valve plug 140 is limited by lips
1 8 as radially outward movement of collet fingers 154 is disallowed by ball retainer 144.
Each valve assembly 136 is retained within one of the axial openings 146 by a retainer pin
142 and a retainer pin 152. Axial movement of piston assembly 138 is initially prevented by
retainer pin 142. A seal, depicted as o-ring 162, prevents fluid travel around piston assembly
138 through opening 146.
[0031] Ball retainer 144 includes a ball retainer body 164 having an o-ring groove 166,
a pin receiver 168, a ball discharge opening 170, a reentry barrier groove 172 having a
reentry barrier 174 disposed therein, as best seen in figure 5. Ball retainer body 164 has an
inner diameter 176 that is sized to receive collet fingers 154 therein such that collet fingers
154 are radially outwardly constrained to retain valve plug 140 within piston body 148, as
best seen in figure 3A. Inner diameter 176 is also sized to receive valve plug 140 therein
during certain operating modes of valve assembly 136. Ball discharge opening 170 is sized
to allow the passages of valve plug 140 therethrough. Reentry barrier 174, depicted as a cring
that extends around reentry barrier groove 172 of ball retainer body 164 and at least
partially into ball discharge opening 170, resists the movement of valve plug 140 from inside
ball retainer body 164 to outside of ball retainer body 164 and prevents movement of valve
plug 140 from outside ball retainer body 164 to inside of ball retainer body 164. As
illustrated, pin 152 is received within pin receiver 168 to prevent axial movement of ball
retainer body 164. A seal, depicted as o-ring 176, prevents fluid travel around ball retainer
body 164 through opening 146.
[0032] Figure 3A represents the running cc
which valve assemblies 136 are secured within valve assembly housing 1 4 and valve plugs
140 are disposed within piston bodies 148. In this configuration, an internal differential
pressure, wherein the pressure inside of base pipe 102 is greater than the pressure outside of
base pipe 102, may be applied to the tubular string deploying flow control screens 100.
Specifically, the internal differential pressure will travel through production ports 108 but
reverse flow through flow control screens 100 is prevented by valve assemblies 136 as valve
plugs 140 seat on shoulders 160, as best seen in figure 3A. Repeated pressure cycles may be
applied to the tubular as long as the pressure remains below the shear pressure of retainer pins
142.
[0033] When it is desired to operate flow control screens 100 from the running
configuration to the sheared configuration, the internal differential pressure may be raised to
a predetermined threshold pressure above the shear pressure of retainer pins 142 causing
retainer pins 142 to shear and piston assemblies 138 have shifted to the left, as best seen in
figure 3B. In this configuration, valve assemblies 136 continue to hold pressure and prevent
reverse fluid flow through flow control screens 100 from production ports 108 to filter
medium 112. Once the internal differential pressure is released and an external differential
pressure, wherein the pressure outside base pipe 102 is greater than the pressure inside base
pipe 102, is applied to flow control screens 100, valve plugs 140 are expelled from piston
assemblies 138 as radially outward movement of collet fingers 154 is no longer disallowed by
ball retainer, as best seen in figure 3C. Once expelled, valve plugs 140 enters an annular
region inside of valve assembly housing 124 via ball discharge opening 170 passing through
reentry barrier 174 which resists but does not prevent the movement of valve plug 140 from
inside ball retainer body 164 to outside of ball retainer body 164, as best seen in figure 3D.
Once discharged, reentry of a valve plug 140 into a valve assembly 136 is disallowed by
reentry barriers 174, such that valve assemblies 136 no longer prevent reverse fluid flow
placing flow control screens 100 in their production configuration.
[0034] While this invention has been described with reference to illustrative
embodiments, this description is not intended to be construed in a limiting sense. Various
modifications and combinations of the illustrative embodiments as well as other
embodiments of the invention will be apparent to persons skilled in the art upon reference to
the description. It is, therefore, intended that the appended claims encompass any such
modifications or embodiments.

What is claimed is:
1. A flow control screen having a fluid flow path between an interior of a base
pipe and a filter medium, the flow control screen comprising:
a valve assembly disposed within the fluid flow path including a piston body, a valve
plug and a ball retainer having an opening, the piston body having an internal seat and a
collet assembly that is radially outwardly constrained by the ball retainer in a first operating
position to retain the valve plug in the piston body and radially outwardly unconstrained by
the ball retainer in a second operating position,
wherein an internal differential pressure seats the valve plug on the internal seat to
prevent reverse flow;
wherein a predetermined internal differential pressure on the valve plug causes the
piston body to shift from the first operating position to the second operating position while
continuing to prevent reverse flow; and
wherein, in the second operating position, an external differential pressure causes the
valve plug to be expelled from the valve assembly through the opening of the ball retainer,
thereby no longer preventing reverse flow.
2. The flow control screen as recited in claim 1 wherein at least a portion of the
collet assembly is slidably positioned within the ball retainer in the first operating position.
3. The flow control screen as recited in claim 1 wherein operation of the piston
assembly from the first operating position to the second operation position is prevented by a
retainer pin until the predetermined internal differential pressure acts on the valve plug.
4. The flow control screen as recited in claim 1 wherein the valve plug further
comprises a spherical blocking member.
5. The flow control screen as recited in claim 1 wherein the collet assembly
further comprises a plurality of collet fingers having radially inwardly projecting lips.
6. The flow control screen as recited in claim 1 wherein the collet assembly
further comprises a plurality of collet fingers having radially outwardly projecting lips.
7. The flow control screen as recite*
further comprises a plurality of collet fingers having radially inwardly and outwardly
projecting lips.
8. The flow control screen as recited in claim 1 further comprising a reentry
barrier operably associated with the ball retainer to prevent reentry of the valve plug into the
valve assembly.
9. The flow control screen as recited in claim 8 wherein the reentry barrier
further comprises a c-ring positioned around the ball retainer.
10. The flow control screen as recited in claim 8 wherein the reentry barrier at
least partially extends into the opening of the ball retainer.
11. The flow control screen as recited in claim 8 wherein the reentry barrier resists
exit of the valve plug from the valve assembly.
12. A flow control screen having a flu
pipe and a filter medium, the flow control screen comprising:
a plurality of circumferentially distributed valve assemblies disposed within the fluid
flow path, each valve assembly including a piston body, a valve plug and a ball retainer
having an opening, the piston body having an internal seat and a collet assembly that is
radially outwardly constrained by the ball retainer in a first operating position to retain the
valve plugs in the piston body and radially outwardly unconstrained by the ball retainer in a
second operating position,
wherein an internal differential pressure seats the valve plugs on the internal seats to
prevent reverse flow;
wherein a predetermined internal differential pressure on the valve plugs causes the
piston bodies to shift from the first operating position to the second operating position while
continuing to prevent reverse flow; and
wherein, in the second operating position, an external differential pressure causes the
valve plugs to be expelled from the valve assemblies through the openings of the ball
retainers, thereby no longer preventing reverse flow.
13. The flow control screen as recited in claim 12 wherein operation of each
piston assembly from the first operating position to the second operation position is prevented
by a retainer pin until the predetermined internal differential pressure acts on the valve plug.
14. The flow control screen as recited in claim 12 wherein the valve plugs further
comprise spherical blocking members.
15. The flow control screen as recited in claim 12 wherein each valve assembly
further comprises a reentry barrier operably associated with the ball retainer to prevent
reentry of the valve plugs into the valve assemblies.
16. The flow control screen as recited in claim 15 wherein each reentry barrier
further comprises a c-ring positioned around the ball retainer.
17. The flow control screen as recited in claim 15 wherein the reentry barriers at
least partially extend into the openings of the ball retainers.
18. The flow control screen as recited
resist exit of the valve plugs from the valve assemblies.
19. A method for operating a flow cont
disposing at least one valve assembly within a fluid flow path between an interior of a
base pipe and a filter medium;
retaining a valve plug within a piston body of the valve assembly by radially
outwardly constraining a collet assembly in a first operating position of the piston body with
a ball retainer;
applying an internal differential pressure to seat the valve plug on an internal seat of
the piston body to prevent reverse flow;
applying a predetermined internal differential pressure on the valve plug to shift the
piston body from the first operating position to a second operating position while continuing
to prevent reverse flow; and
applying an external differential pressure to expel the valve plug from the valve
assembly through an opening in the ball retainer, thereby no longer preventing reverse flow.
20. The method as recited in claim 19 further comprising preventing reentry of the
valve plug into the valve assembly with a reentry barrier disposed around the ball retainer and
extending at least partially into the opening.