U.S. patent application number 12/058062 was filed with the patent office on 2009-04-02 for sliding sleeve valve assembly with sand screen.
This patent application is currently assigned to SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Balkrishna Gadiyar, Matthew R. Hackworth, John Lassek, Jorge Lopez de Cardenas, Hugo Morales, Gary L. Rytlewski, John R. Whitsitt.
Application Number | 20090084553 12/058062 |
Document ID | / |
Family ID | 40506877 |
Filed Date | 2009-04-02 |
United States Patent
Application |
20090084553 |
Kind Code |
A1 |
Rytlewski; Gary L. ; et
al. |
April 2, 2009 |
SLIDING SLEEVE VALVE ASSEMBLY WITH SAND SCREEN
Abstract
A system and method for completing a well with multiple zones of
production is provided, including a casing having a plurality of
valves integrated therein for isolating each well zone,
establishing communication between each underlying formation and
the interior of the casing, delivering a treatment fluid to each of
the multiple well zones, and filtering produced fluids from each
underlying formation.
Inventors: |
Rytlewski; Gary L.; (League
City, TX) ; Morales; Hugo; (Katy, TX) ;
Gadiyar; Balkrishna; (Katy, TX) ; Lassek; John;
(Katy, TX) ; Whitsitt; John R.; (Houston, TX)
; Lopez de Cardenas; Jorge; (Sugar Land, TX) ;
Hackworth; Matthew R.; (Manvel, TX) |
Correspondence
Address: |
SCHLUMBERGER RESERVOIR COMPLETIONS
14910 AIRLINE ROAD
ROSHARON
TX
77583
US
|
Assignee: |
SCHLUMBERGER TECHNOLOGY
CORPORATION
Sugar Land
TX
|
Family ID: |
40506877 |
Appl. No.: |
12/058062 |
Filed: |
March 28, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11834869 |
Aug 7, 2007 |
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12058062 |
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10905073 |
Dec 14, 2004 |
7387165 |
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11834869 |
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60938920 |
May 18, 2007 |
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60987320 |
Nov 12, 2007 |
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Current U.S.
Class: |
166/305.1 ;
166/205 |
Current CPC
Class: |
E21B 2200/06 20200501;
E21B 43/08 20130101; E21B 43/26 20130101; E21B 43/14 20130101; E21B
34/06 20130101; E21B 34/14 20130101 |
Class at
Publication: |
166/305.1 ;
166/205 |
International
Class: |
E21B 43/14 20060101
E21B043/14; E21B 34/14 20060101 E21B034/14 |
Claims
1. A valve apparatus for use in a wellbore intersecting a
reservoir, comprising: a housing being fixed to the wellbore
proximate the reservoir by cement, the housing defining an inner
bore and having a port for establishing a flow path between the
reservoir and the inner bore of the housing; a sliding sleeve
arranged within the inner bore of the housing, and being adapted to
shift between a closed position whereby the sliding sleeve
interrupts the flow path between the reservoir and the inner bore
of the housing and an open position whereby the flow path between
the reservoir and the inner bore of the housing is substantially
uninterrupted; and a filtering assembly arranged within the inner
bore of the housing axially adjacent to the sliding sleeve, the
filtering assembly comprising: a perforated base pipe and a screen
arranged between the housing and the perforated base pipe, the
filtering assembly being adapted to shift between a filtering
position wherein the screen is aligned with the port in the housing
and a non-filtering position wherein the screen is not aligned with
the port in the housing.
2. The valve apparatus of claim 1, further comprising a protector
adapted to engage the base pipe to isolate the screen from the
inner bore of the housing.
3. The valve apparatus of claim 2, wherein the protector comprises:
a removable mechanical sleeve formed around an inner surface of the
base pipe having a profile for engagement with an actuator, wherein
the actuator is one selected from a group consisting of: a drop
ball, a dart, and a service tool.
4. The valve apparatus of claim 2, wherein the protector comprises:
a set of removable plugs inserted into the perforated base pipe and
protruding radially inward toward the inner bore of the housing for
engagement with an actuator, wherein the actuator is one selected
from a group consisting of: a drop ball, a dart, and a service
tool.
5. The valve apparatus of claim 2, wherein the protector comprises:
a sacrificial member formed around an inner surface of the base
pipe, wherein the sacrificial member is formed from a dissolvable
material.
6. The valve apparatus of claim 2, further comprising a sealing
mechanism connected to the housing and biased radially inward from
the inner bore, the sealing mechanism being adapted to engage a
work string extending from a surface location through the inner
bore of the housing for delivering cement into the wellbore at a
location below the housing.
7. The valve of claim 2, wherein the filtering assembly further
comprises a metering surface connected to the base pipe, the
metering surface defining a radially-outward protruding profile
counter to an inner surface of the housing, the radially-outward
protruding profile adapted to meter the shifting of the filtering
assembly.
8. A method for use in a wellbore having a plurality of well zones,
comprising: running a casing having a plurality of valves formed
therein from a surface down into the wellbore such that each valve
is proximate a well zone; cementing the casing to the wellbore;
selecting a target valve proximate a target well zone; opening the
target valve to establish communication between the surface and the
target well zone; treating the target well zone by pumping a
treatment fluid from the surface to the target well zone via the
target valve; and manipulating at least one valve into a filtering
state; filtering a production fluid flowing from at least one well
zone into the casing; and producing the production fluid to the
surface.
9. The method of claim 8, wherein opening the target valve
comprises: pumping a dart from the surface into the casing to move
a sleeve in the target valve.
10. The method of claim 8, wherein opening the target valve
comprises: dropping a ball from the surface into the casing to move
a sleeve in the target valve.
11. The method of claim 8, wherein opening the target valve
comprises: running a service tool into the well to the target valve
of the target well zone; and engaging a sleeve in the target valve
with the service tool and shifting the sleeve.
12. The method of claim 8, wherein opening the target valve
comprises: pressurizing a control line running from a location
above the target valve to shift a sleeve in the target valve.
13. The method of claim 8, wherein manipulating at least one valve
into a filtering state comprises: shifting a sand screen assembly
over a port within the at least one valve, the screen assembly
comprising: a perforated base pipe and a screen.
14. The method of claim 13, further comprising: protecting the
screen with a removable sleeve arranged around the perforated base
pipe; and removing the sleeve from the perforated base pipe before
producing the production fluid.
15. The method of claim 13, further comprising: protecting the sand
screen with a sacrificial member arranged around the perforated
base pipe; and dissolving the sacrificial member before producing
the production fluid.
16. The method of claim 8, further comprising: monitoring a well
parameter proximate a well zone with a cable running from the
surface to the well zone external the casing.
17. A system for use in a wellbore having a plurality of well
zones, comprising: a casing fixed to the wellbore by cement; a
plurality of valves connected to the casings, each valve
comprising: (i) a flow port for establishing communication between
the casing and one of the well zones, (ii) a sliding sleeve
disposed therein for regulating communication via the flow port,
and (iii) a filtering assembly disposed therein and axially
adjacent to the sliding sleeve, the filtering assembly being
adapted to shift between a filtering position wherein filtering
assembly is aligned with the flow port and a non-filtering position
wherein the filtering assembly is not aligned with the flow port; a
first actuator adapted to selectively shift the sliding sleeve of
each of the plurality of valves; and a second actuator adapted to
selectively shift the filtering assembly of each of the plurality
of valves.
18. The system of claim 17, wherein the first actuator is one
selected from a group consisting of: (i) a drop ball selected to
engage the sliding sleeve of each valve, (ii) a dart selected to
engage the sliding sleeve of each valve, and (iii) a work string
having an outer profile selected to engage the sliding sleeve of
each valve and defining a tubular bore.
19. The system of claim 17, wherein the second actuator is one
selected from a group consisting of: (i) a drop ball selected to
engage the filtering assembly of each valve, (ii) a dart selected
to engage the filtering assembly of each valve, and (iii) a work
string having an outer profile selected to engage the filtering
assembly of each valve and defining a tubular bore.
20. The system of claim 17, wherein the first actuator comprises a
first control line connected between a surface location and a
piston area above the sliding sleeve of an upper valve among the
plurality of valves, and wherein the second actuator comprises a
second control line connected between a piston area below the
sliding sleeve of the upper valve and a piston area above the
filtering assembly of a lower valve among the plurality of
valves.
21. The system of claim 17, wherein each of the plurality of valves
further comprises: a removable protector tool for temporarily
protecting the filtering assembly.
22. The system of claim 18, wherein the work string further
comprises: a sealing mechanism arranged above the outer profile,
wherein the tubular bore extends below the sealing mechanism.
23. The system of claim 18, wherein the work string further
comprises: a first sealing mechanism arranged above the outer
profile, wherein the tubular bore extends below the sealing
mechanism; and a removable second sealing mechanism arranged below
the outer profile, wherein the tubular bore is temporarily
interrupted by the second sealing mechanism.
24. The system of claim 18, wherein the work string further
comprises: a sealing mechanism arranged below the outer profile,
wherein the tubular bore extends below the sealing mechanism.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 11/834,869, filed Aug. 7, 2007, and entitled
"System For Completing Multiple Well Intervals," which is a
divisional application of U.S. patent application Ser. No.
10/905,073, filed Dec. 14, 2004, and entitled "System For
Completing Multiple Well Intervals." This application further
claims priority to U.S. Provisional Application No. 60/938,920,
filed May 18, 2007, entitled "Sliding Sleeve Valve Assembly with
Sand Screen;" and U.S. Provisional Application No. 60/987,302,
filed Nov. 12, 2007, entitled "Sliding Sleeve Valve Assembly with
Sand Screen."
TECHNICAL FIELD
[0002] The present invention relates generally to recovery of
hydrocarbons in subterranean formations, and more particularly to a
system and method for delivering treatment fluids to wells having
multiple production zones or a single production zone with a
relatively large reservoir height.
BACKGROUND
[0003] In typical wellbore operations, various treatment fluids may
be pumped into the well and eventually into the formation to
restore or enhance the productivity of the well. For example, a
non-reactive "fracturing fluid" or a "frac fluid" may be pumped
into the wellbore to initiate and propagate fractures in the
formation thus providing flow channels to facilitate movement of
the hydrocarbons to the wellbore so that the hydrocarbons may be
pumped from the well. In such fracturing operations, the fracturing
fluid is hydraulically injected into a wellbore penetrating the
subterranean formation and is forced against the formation strata
by pressure. The formation strata is forced to crack and fracture,
and a proppant is placed in the fracture by movement of a
viscous-fluid containing proppant into the crack in the rock. The
resulting fracture, with proppant in place, provides improved flow
of the recoverable fluid (i.e., oil, gas or water) into the
wellbore. In another example, a reactive stimulation fluid or
"acid" may be injected into the formation. Acidizing treatment of
the formation results in dissolving materials in the pore spaces of
the formation to enhance production flow.
[0004] Currently, in wells with multiple production zones, it may
be necessary to treat various formations in a multi-staged
operation requiring many trips downhole. Each trip generally
consists of isolating a single production zone, perforating the
isolated zone, and then delivering the treatment fluid to the
isolated zone. Since several trips downhole are required to isolate
and treat each zone, the complete operation may be very time
consuming and expensive.
[0005] Accordingly, there exists a need for systems and methods to
deliver treatment fluids to multiple zones of a well in a single
trip downhole.
SUMMARY
[0006] The present invention relates to a system and method for
delivering a treatment fluid to a well having multiple production
zones or a single production zone with a relatively large reservoir
height. According to some embodiments of the present invention, a
well completion system having one or more zonal communication
valves is installed and/or deployed in a wellbore to provide zonal
isolation and establish hydraulic communication with each
particular well zone for facilitating delivery of a treatment fluid
or squeezing remedial cement. Each communication valve may be set
to an open position, a closed position, and a filtering
position.
[0007] Other or alternative embodiments of the present invention
will be apparent from the following description, from the drawings,
and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The manner in which these objectives and other desirable
characteristics can be obtained is explained in the following
description and attached drawings in which:
[0009] FIG. 1 illustrates a profile view of an embodiment of the
multi-zonal well completion system of the present invention having
zonal communication valves being installed/deployed in a
wellbore.
[0010] FIGS. 2A-2C illustrate cross-sectional profile views of an
embodiment of a sliding sleeve zonal isolation valve of the present
invention.
[0011] FIGS. 3A-3C illustrate cross-sectional profile views of an
embodiment of a sliding sleeve zonal isolation valve of the present
invention being installed/deployed in a wellbore, and shifted
between closed, open, and filtering positions.
[0012] FIGS. 4A-4B illustrate cross-sectional profile views of an
embodiment of a sliding sleeve zonal isolation valve of the present
invention having a screen protector that is a mechanical
sleeve.
[0013] FIGS. 5A-5B illustrate cross-sectional profile views of an
embodiment of a sliding sleeve zonal isolation valve of the present
invention having a screen protector that is a set of shearable
caps.
[0014] FIGS. 6A-6B illustrate cross-sectional profile views of an
embodiment of a sliding sleeve zonal isolation valve of the present
invention having a screen protector that is a dissolvable or
degradable sheet or coating.
[0015] FIG. 7 illustrates a cross-sectional profile view of an
embodiment of a sliding sleeve zonal isolation valve of the present
invention having a metering mechanism.
[0016] FIG. 8 illustrates a cross-sectional profile view of an
embodiment of a system of sliding sleeve zonal isolation valves of
the present invention having control lines.
[0017] FIG. 9 illustrates a cross-sectional profile view of an
embodiment of a system of sliding sleeve zonal isolation valves of
the present invention having a sealing assembly for sealing with a
downhole string.
[0018] FIGS. 10A-10F illustrate cross-sectional profile views of an
embodiment of an operational method of the present invention with a
downhole tool having a sealing mechanism (e.g., a packer assembly
located above the shifting profile).
[0019] FIGS. 11A-10F illustrate cross-sectional profile views of an
embodiment of an operational method of the present invention with a
downhole tool having a sealing mechanism to facilitate fracturing
operations.
[0020] 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
[0021] In the following description, numerous details are set forth
to provide an understanding of the present invention. However, it
will be understood by those skilled 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.
[0022] In the specification and appended claims: the terms
"connect", "connection", "connected", "in connection with", and
"connecting" are used to mean "in direct connection with" or "in
connection with via another element"; and the term "set" is used to
mean "one element" or "more than one element". As used herein, the
terms "up" and "down", "upper" and "lower", "upwardly" and
downwardly", "upstream" and "downstream"; "above" and "below"; and
other like terms indicating relative positions above or below a
given point or element are used in this description to more clearly
describe some embodiments of the invention. Moreover, the term
"sealing mechanism" includes: packers, bridge plugs, downhole
valves, sliding sleeves, baffle-plug combinations, polished bore
receptacle (PBR) seals, and all other methods and devices for
temporarily blocking the flow of fluids through the wellbore.
Furthermore, the term "treatment fluid" includes any fluid
delivered to a formation to stimulate production including, but not
limited to, fracing fluid, acid, gel, foam or other stimulating
fluid.
[0023] Generally, this invention relates to a system and method for
completing multi-zone wells (or, alternatively, wells with
relatively large reservoir heights) by delivering a treatment fluid
to achieve productivity, or for delivering remedial cement to
target areas as necessary. Typically, such wells are completed in
stages that result in very long completion times (e.g., on the
order of four to six weeks). The present invention may reduce such
completion time (e.g., to a few days) by facilitating multiple
operations, previously done one trip at a time, in a single
trip.
[0024] In general, embodiments of the present invention include a
system of one or more zonal isolation valves movable (e.g., by
shifting, rotating, indexing, or other means) between three
positions: (1) an open position whereby a treatment fluid may be
pumped/injected into the well, (2) a closed position whereby
communication is interrupted between the well and the interior of
the valve, and (3) a filtering position whereby a fluid (e.g., a
produced hydrocarbon or other production or return fluid) is free
to flow from the well into the interior of the valve via a
filtering medium (e.g., sand screen).
[0025] FIG. 1 illustrates an embodiment of the well completion
system of the present invention for use in a wellbore 10. The
wellbore 10 may include a plurality of well zones (e.g., formation,
production, injection, hydrocarbon, oil, gas, or water zones or
intervals) 12A, 12B. The completion system includes a casing 20
having one or more zonal isolation valves 25A, 25B arranged to
correspond with each formation zone 12A, 12B. The zonal isolation
valves 25A, 25B function to regulate hydraulic communication
between the axial bore of the casing 20 and the respective
formation zone 12A, 12B. For example, to deliver a treatment fluid
to formation zone 12B, valve 25B is opened and valve 25A is closed.
Therefore, any treatment fluid delivered into the casing 20 from
the surface will be delivered to zone 12B and bypass zone 12A. The
valves 25A, 25B of the well completion system may include a sliding
sleeve assembly 36 to selectively open or close a port 32 and a
sand screen assembly 38 (or other filter assembly) to selectively
filter or not filter the port 32. Furthermore, while this
embodiment describes a completion system including a casing, in
other embodiments any tubular string may be used including a
casing, a liner, a tube, a pipe, or other tubular member. While
only two valves are shown, in other system embodiments there may be
one, two, three, or more valve assemblies installed in a well
casing.
[0026] Regarding use of the well completion system of the present
invention, some embodiments may be deployed in a wellbore (e.g., an
open or uncased hole) as a temporary completion. In such
embodiments, sealing mechanisms may be employed between each valve
and within the annulus defined by the tubular string and the
wellbore to isolate the formation zones being treated with a
treatment fluid. However, in other embodiments the valves and
casing of the completion system may be cemented in place as a
permanent completion. In such embodiments, the cement serves to
isolate each formation zone.
[0027] FIGS. 2A-2C illustrate an embodiment of a zonal isolation
valve 12. FIG. 2A illustrates a zonal isolation valve in a
"filtering position" (e.g., for production). FIG. 2B illustrates a
zonal isolation valve in an "open port position" (e.g., for
treatment). And, FIG. 2C illustrates a zonal isolation valve in a
"closed port position" (e.g., for bypassing the underlying well
zone).
[0028] The zonal isolation valve 25 includes an outer housing 30
having an axial bore therethrough and which is connected to or
integrally formed with a casing (or liner, or any tubular string
both cemented or uncemented). The housing 30 has a set of housing
ports 32 formed therein for establishing communication between the
wellbore and the axial bore of the housing. In some embodiments,
the housing may protrude radially outward to minimize the gap
between the valve 12 and wellbore 10 (as shown in FIG. 1). By
minimizing the gap between the housing and the formation, the
amount of cement interfering with communication via the ports 32 is
also minimized. A sleeve 36 is arranged within the axial bore of
the housing 30. Furthermore, a tubular sand screen assembly 38 is
arranged within the housing 30 and connected to the sleeve 36. The
sand screen assembly 38 includes a filtering media (e.g., wire-wrap
or wire-mesh) to filter produced fluids from the ports 32 when the
sand screen assembly 38 is aligned with the ports 32. The sleeve 36
is moveable between: (1) an "open port position" whereby a flow
path is maintained between the wellbore and the axial bore of the
housing 30 via the set of ports 32, (2) a "closed port position"
whereby the flow path between the wellbore and the axial bore of
the housing 30 via the set of ports 32 is obstructed by the sleeve
36, and (3) a "filtering position" whereby the flow path between
the wellbore and the axial bore of the housing 30 via the set of
ports 32 is interrupted by the sand screen assembly 38, which
facilitates filtering of fluids following such flow path.
[0029] Actuation of the zonal communication valve (sliding sleeve
and sand screen assemblies) may be achieved by any number of
mechanisms including, but not limited to, darts (see U.S. Pub. No.
2006/0124310, which disclosure of dart actuation is incorporated
herein by reference), tool strings, control lines, (see U.S. Pub.
No. 2006/0124312, which disclosure of control line actuation is
incorporated herein by reference), electrical lines selectively
powering solenoids for valve shifting, and drop balls (see U.S.
Pub. Nos. 2006/0124312 and 2007/0044958, each of which discloses
use of drop ball actuation, are incorporated herein by reference).
Moreover, embodiments of the present invention may include wireless
actuation of the zonal communication valve as by pressure pulse,
electromagnetic radiation waves, seismic waves, acoustic signals,
and other wireless signaling.
[0030] With reference to FIGS. 3A-3C, embodiments of the present
invention further include methods of running the above-described
system and assemblies. In one such embodiment, as shown in FIG. 3A,
valves 110 are provided comprising a housing 112 with one or more
ports or sets of ports 114 formed therein, a sliding sleeve 122 and
a filter assembly 120. The filer assembly 120 comprises a screen
124, a perforated base pipe section 126, and a screen protector
128. The screen protector 128 protects the screen 124 during
run-in, installation, cementing, and treatment operations against
abrasion, erosion, contamination, or other damage resulting from
movement through the wellbore and/or initial operation of the well
system. The screen protector 128 may be a mechanical sleeve 128A
(FIG. 4A-4B), a set of shearable caps 128B (FIG. 5A-5B), or a
dissolvable or degradable sheet or coating 128C (FIG. 6A-6B), which
is removed before production.
[0031] In operation, once run-in on casing, installed and cemented
into place, a target valve 110 is actuated to shift the sleeve 124
from the closed to the open position. In the embodiment illustrated
in FIG. 3B, a service tool (or other tool or work string) 150
having a mating profile 152, a treatment port 156, and a set of
sealing elements 158 is positioned inside the housing 112 of the
valve 110 to sealingly engage the sleeve 122. The sleeve 122 is
shifted to open the port 114 and created a treatment flow path via
a bore in the service tool 150. With the port 114 open, a treatment
fluid is pumped through the port 156 of the service tool 150 and
into the formation. When the treatment is completed, the service
tool 150 is used to shift the sleeve 122 back to the closed
position, thus controlling potential fluid loss. The service tool
is repositioned to the next valve (not shown) in the well,
repeating the operational described above: Shift open, treat, shift
closed. Each successive zone is treated in this manner. The
treatments may be done bottom up, top down, or any other sequence.
Alternatively, it is understood that various other methods (as
described herein) may be used to shift each valve between the open
and closed positions. In alternative embodiments, after targeted
zonal treatment, the valve may be left open as subsequent upper
valves are opened for treatment in reliance on the sand fill
forming to isolate off the lower zones.
[0032] With respect to FIG. 3C, after each zone is treated, the
filter assembly 120 is mechanically shifted across the port 114
formed in the housing 112 of the valve 110. The screen protector
128 is then removed such that the screen 124 and base pipe 126
filter and produced fluids from the reservoir zone into the well.
Produced fluid may flow into the well through the screened ports
114.
[0033] The screen protector may be removed to facilitate production
by various methods and employing various tools. In one embodiment,
as shown in FIG. 4A-4B, a mechanical sleeve 128A is provided to
protect the screen 124. The mechanical sleeve may be disposed on
the inner wall of the perforated base pipe 126 and include a
profile for engagement with an actuator (not shown) such as a drop
ball, a pumpable dart, or a service tool. In some embodiments, the
mechanical sleeve 128A may be held in place by a shear screw 129 or
any other removable fastener (e.g., epoxy/adhesive, bolt, clip, and
so forth). In operation, the actuator is made to engage the profile
of the mechanical sleeve 128A and pressure is applied to the
actuator to remove the sleeve from engagement with the base pipe
126 to establish a filtered flow path from the reservoir to the
well via the screen 124 and perforated base pipe 126.
Alternatively, in another embodiment (not shown), the mechanical
sleeve may be punctured (instead of shifted) by a mechanical
punching tool run from surface.
[0034] In another embodiment, as shown in FIGS. 5A-5B, a set of
removable caps or plugs 128B is provided such that each perforation
hole in the base pipe 126 is covered by a cap or plug to isolate
the screen 124. In operation, the set of caps or plugs 128B is
removable by disengagement with the perforated base pipe 126 using
a drop ball, dart, or service tool to shear or otherwise remove
each cap or plug. The ball, dart, or service tool has a profile
with an outer diameter sufficiently large enough to engage the
radially inward protruding caps or plugs. Once the caps or plugs
128B are removed from engagement with the base pipe 126, a filtered
flow path from the reservoir to the well via the screen 124 and
perforated base pipe 126 is established.
[0035] In still another embodiment, as shown in FIGS. 6A-6b, a
sacrificial member 128C (e.g., a dissolvable or degradable sheet or
coating) is provided such that each perforation hole in the base
pipe 126 is covered by the sacrificial member to temporarily
isolate the screen 124. The sacrificial member 128C may comprise a
dissolvable or degradable sheet or coating disposed on the inner
wall of the perforated base pipe 126. Some embodiments of such
sacrificial members are as those described in U.S. Ser. No.
11/555,404, filed Nov. 1, 2006, which is incorporated herein by
reference. In operation, the sacrificial member 128C is removed
(e.g., by dissolving in wellbore fluids or a fluid agent or by
breaking up where the member is frangible) from the base pipe 126
to establish a filtered flow path from the reservoir to the well
via the screen 124 and perforated base pipe 126.
[0036] Where the sacrificial member 128C is formed of a dissolvable
material, in one embodiment, the dissolvable material may be
selected to dissolve at a desired rate when exposed to well fluid
within wellbore. Accordingly, the dissolving of the temporary
covering 128C is controlled by submerging dissolvable material in
fluids found within wellbore during movement of the valve 110 to a
desired location within the wellbore. Alternatively, fluid agents
also can be added to the wellbore to control the dissolving of
material. The dissolvable material may be formed from a variety of
materials depending on the specific application and environment in
which it is used. For example, the materials selected may vary
depending on the potential heat and pressures in a given wellbore
environment. The materials selected also may depend on the types of
well fluids encountered in a given wellbore environment. Examples
of dissolvable material comprise highly reactive metals such as
calcium, magnesium or alloys thereof, or materials that dissolve in
acidic or basic fluids, e.g. aluminum, polymers or specially
formulated plastics. Examples of suitable materials used to form a
coating comprise aluminum or other metals that can be removed with
acid or specifically formulated chemicals. Other examples of
materials comprise low-temperature plastics or elastomers that fail
at higher pressures or temperatures. Additional examples of
suitable materials comprise metallic coatings that differ greatly
in thermal expansion coefficient relative to their carrier
material, such that the coating material fractures and breaks away
at elevated temperatures.
[0037] Still with respect to FIGS. 6A-6B, in some embodiments of
the present invention, the sacrificial member 128C is formed by a
dissolvable element temporarily protected by a coating designed to
prevent exposure of dissolvable material to dissolving fluids until
a desired time following the valve installation and/or treatment
operation. The coating can be degraded or otherwise removed by
providing an appropriate input downhole. For example, the coating
can be selected such that it is sensitive to heat. In this
embodiment, once the coating is exposed to sufficient heat at a
desired depth within wellbore, the coating is degraded which
exposes the inner element to well fluids able to dissolve the inner
layer. In another embodiment, the coating can be designed to
degrade under sufficient pressure provided either naturally at
certain wellbore depths or artificially by applying pressure to the
wellbore from, for example, a surface location. In other
embodiments, the coating can be designed to degrade when exposed to
specific chemicals directed downhole. In any of these embodiments,
the coating prevents the disappearance of the inner element until a
specific time period in which the pressure or temperature, for
example, causes the coating to fail, thus initiating dissolving of
inner element. Once the inner element is dissolved, the sacrificial
member 128C is gone and the screen 124 is exposed for filtering
operations.
[0038] Now, with respect to moving the filtering assembly into
place, the filter assembly may be mechanically shifted across the
ports by various methods and employing various tools, including:
drop balls, pumped darts, or by mating profiles in the service tool
(or other tool string). Other methods of moving the filter assembly
include non-mechanical (e.g., hydraulic) means. For example, as
shown in FIG. 7, the filter assembly 120 may be metered to move
relatively slowly downward as soon as the sliding sleeve 122 of the
valve 110 is shifted into the open position. Metering oil through a
tight restriction 121 may be used to provide a time delay for the
treatment to occur before the filter assembly 120 is displaced
across the port 114. In another example, as shown in FIG. 8, where
an upper valve 110U having a port 114U, a sleeve 122U and a filter
assembly 120U and a lower valve 110L having a port 114L, a sleeve
122L and a filter assembly 120L is provided, a first control line
1001 is run between a surface location (or, alternatively, from a
control hub located above the valves but below the surface) and an
area A1 within valve 110U defined by the sliding sleeve 122U and
above the piston 127U. A second control line 1002 is run between an
area A2 within valve 110U defined by the sliding sleeve 122U and
below the piston 127U and an area A3 within valve 110L defined by
the filter assembly 120L and above the piston 125L. In this case,
when the upper valve 110U is opened by communicating pressure from
the surface down control line 1001, the second control line 1002 is
pressurized to shift the filter assembly 120L of the lower valve
110L across the port 1114L.
[0039] With respect to FIG. 9, in an alternative embodiment of the
present invention, a system of zonal isolation valves 200 run
casing 230 and installed in a well 210 includes a bottom valve 200A
having a housing 201 with a port 202 formed therein and a sliding
sleeve 204 and filtering assembly 206 as described in the various
embodiments above. The bottom zonal isolation valve 200A further
includes a sealing mechanism 207 (e.g., o-rings) for sealingly
engaging a work string 220. In operation, the work string 220 may
be run from a surface location to stab through the sealing assembly
207 of the bottom zonal isolation valve 200A. Cement may be pumped
through the work string 220 and squeezed in the annulus formed
between the casing 230 and the well 210. In this way, the valves
200 are bypassed and protected by the sealing assembly 207, and the
need for a screen protector (as described in embodiments above) may
be unnecessary.
[0040] In some embodiments of the present invention, the zonal
isolation system may include a cable (e.g., running down the outer
surface of the casing) for monitoring and surveillance of wellbore
parameters, such as pressure, temperature, pH, strain, and so
forth. This is possible with embodiments of the present
valve-actuated zonal isolation system as perforation operations are
not required; and such perforation operations would likely damage
any installed cable.
[0041] The invention also includes various embodiments of
operational methods for treating multiple zones of a well via a
zonal isolation system. One example is shown in FIGS. 10A-F. In
this method, a work string 330 having a sealing mechanism 332
(e.g., a packer) and a shifting profile 334 is run in a wellbore
300 having a casing 302 cemented in place with a lower zonal
isolation valve 310 and an upper zonal isolation valve 320. The
valves 310, 320 are initially closed (FIG. 10A). The shifting
profile 334 of the work string 330 is used to engage the lower
valve 310 and shift the valve open before setting the sealing
mechanism 332 (FIG. 10B). The lower zone underlying the lower valve
310 is now treated via the work string 330 (FIG. 10C). Once
treatment of the lower zone is complete, the lower valve 310 is
shifted closed using the shifting profile 334 of the work string
330 (FIG. 10D). In an alternative embodiment where the sand fill is
sufficiently plugging the lower zones, the lower valve may not need
to be shifted closed. The valve opening process is repeated to open
the upper valve 320 and the upper zone is treated (FIG. 10E). The
valve closing process is repeated to close the upper valve 320
(FIG. 10F). These processes of opening, treating, and closing
valves may be repeated for any additional valves in the well. Once
all treatment is accomplished, the valves can all be shifted to the
filtering position (as described in previous embodiments) to
facilitate production.
[0042] Another example is shown in FIGS. 11A-F. In this method, a
work string 430 having an upper sealing mechanism 432 (e.g., a
packer), a shifting profile 434, and a lower sealing mechanism 433
(e.g., a bridge plug) is run in a wellbore 400 having a casing 402
cemented in place with a lower zonal isolation valve 410 and an
upper zonal isolation valve 420. The valves 410, 420 are initially
closed (FIG. 11A). The lower sealing mechanism 433 is located below
the lower valve 410 and set and released (FIGS. 11B and 11C). The
shifting profile 434 of the work string 430 is used to engage the
lower valve 410 and shift the valve open before the setting the
upper sealing mechanism 432. The lower zone underlying the lower
valve 410 is now treated via the work string 430 (FIG. 11C). Once
treatment of the lower zone is complete, the upper sealing
mechanism 432 is released and the fill is washed (FIG. 11D) and the
lower sealing mechanism 433 is re-latched and unset (FIG. 11E). The
work string 430 is then moved proximate the upper valve 420 and the
process is repeated (FIG. 11F). In this embodiment, the lower valve
410 may be left open (or alternatively, shifted to the
producing/filtered position) as the lower sealing mechanism 433
provides isolation to the lower zones. Once all treatment is
accomplished, the valves can all be shifted to the filtering
position (as described in previous embodiments) to facilitate
production.
[0043] Yet another example is shown in FIGS. 12A-D. In this method,
a work string 530 having a sealing mechanism 532 (e.g., a packer)
and a shifting profile 534 (located above the sealing mechanism) is
run in a wellbore 500 having a casing 502 cemented in place with a
lower zonal isolation valve 510 and an upper zonal isolation valve
520. The valves 510, 520 are initially closed (FIG. 12A). The
shifting profile 534 of the work string 530 is used to engage the
lower valve 510 and shift the valve open before setting the sealing
mechanism 532 (FIG. 12B). The lower zone underlying the lower valve
now receives annulus pressurize (e.g., using a fracturing means
like hydraulic fracturing) to break the cement external and
proximate the lower valve 510. The sealing mechanism 532 may now be
unset, the work string 530 moved proximate the upper valve 520, and
the sealing mechanism 532 reset to break the cement external and
proximate the lower valve 520 using annulus fracturing means. Once
the targeted zones underlying the valves 510, 520 are fractured,
the zones may be treated via the work string 530. Once all
treatment is accomplished, the valves can all be shifted to the
filtering position (as described in previous embodiments) to
facilitate production.
[0044] While the invention has been disclosed with respect to a
limited number of embodiments, those skilled in the art will
appreciate numerous modifications and variations therefrom. It is
intended that the appended claims cover such modifications and
variations as fall within the true spirit and scope of the
invention.
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