U.S. patent application number 14/793237 was filed with the patent office on 2015-10-29 for chemically targeted control of downhole flow control devices.
The applicant listed for this patent is SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Athar Ali, Frank F. Chang, Kuo-Chiang Chen, Stephen Dyer, Xiangdong Qiu.
Application Number | 20150308224 14/793237 |
Document ID | / |
Family ID | 47554978 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150308224 |
Kind Code |
A1 |
Dyer; Stephen ; et
al. |
October 29, 2015 |
CHEMICALLY TARGETED CONTROL OF DOWNHOLE FLOW CONTROL DEVICES
Abstract
Systems and methods using enhanced flow control devices are
described. The flow control devices can be selectively closed
completely or have its effective flow area reduced to restrict
production (or injection) by use of a chemical trigger mechanism.
In addition, some of the systems described herein deploy specific
targeted chemical tracers, dissolvable in the unwanted production
fluid (e.g. water or gas). These chemical tracers once dissolved
will enter the production stream and be identified at the surface.
The identification will determine which segment of the completion
is producing the unwanted fluid. According to some embodiments, an
appropriate chemical trigger is placed, for example, by pumping
down through the tubing and utilizing intelligent completion valve
to place the chemical, or by spotting with coiled tubing and
bullhead to the formation, or by other methods of chemical
placement. The chemical trigger will only trigger the active
chemical in the appropriate flow control device. This chemical will
then change state--dissolve, create thermal reaction, create a
pressure swell or expand--which in turn allows a mechanical device
to shift position such that a valve in the flow control device
closes, or reduces its flow by restricting the flow area by
swelling/expansion of the active chemical.
Inventors: |
Dyer; Stephen; (Rosharon,
TX) ; Ali; Athar; (Al-Khobar, SA) ; Chang;
Frank F.; (Al-Khobar, SA) ; Qiu; Xiangdong;
(Al-Khobar, SA) ; Chen; Kuo-Chiang; (Sugar Land,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHLUMBERGER TECHNOLOGY CORPORATION |
SUGAR LAND |
TX |
US |
|
|
Family ID: |
47554978 |
Appl. No.: |
14/793237 |
Filed: |
July 7, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13185957 |
Jul 19, 2011 |
9133683 |
|
|
14793237 |
|
|
|
|
Current U.S.
Class: |
166/373 ;
166/316 |
Current CPC
Class: |
E21B 34/063 20130101;
E21B 41/0035 20130101; E21B 34/06 20130101; E21B 43/12 20130101;
E21B 2200/06 20200501 |
International
Class: |
E21B 34/06 20060101
E21B034/06 |
Claims
1. A method of chemically targeting control of flow control devices
installed in a wellbore comprising: by an operator, selecting for
actuation at least one of a plurality of flow control devices
previously installed in a wellbore, leaving at least one of said
plurality of flow control devices as non-selected for actuation;
selecting a triggering chemical fluid configured to selectively
trigger actuation of said flow control devices selected for
actuation and configured not to trigger actuation of said flow
control devices non-selected for actuation; flowing said selected
triggering chemical fluid from a surface location through the
wellbore and to expose both said flow control devices selected for
actuation and said flow control devices non-selected for actuation
to said triggering chemical fluid; selectively triggering
actuations of said flow control devices selected for actuation,
said actuations being caused by one or more chemical reactions
resulting from exposure with said triggering chemical fluid,
leaving un-actuated said flow control devices non-selected despite
being exposed to said triggering chemical fluid.
2. A method according to claim 1 wherein the introduced chemical
causes an exothermic chemical reaction used to actuate a choking
member.
3. A method according to claim 1 wherein at least one of the
plurality of flow control devices includes a pneumatic valve, and
the introduced chemical causes a reaction to generate gas to
actuate the pneumatic valve.
4. A method according to claim 3 wherein the gas generating
reaction includes an acid reacting with one or more substances
selected from a group consisting of sodium carbonate, sodium
bicarbonate, calcium carbonate and sodium nitride (NaNO.sub.2).
5. A method according to claim 1 wherein the introduced chemical
reacts with a material in the flow control device so as to release
a plurality of sealing members that seal one or more orifices in
flow control device.
6. A method according to claim 5 wherein the sealing members are
spherical in shape.
7. A method according to claim 5 wherein the sealing members are of
irregular shape.
8. A method according to claim 1 wherein the introduced chemical
causes swelling of portions within the flow control device so as to
restrict fluid flow within the flow control device.
9. A method according to claim 1 wherein the introduced chemical is
located downhole and is automatically released in the presence of
an unwanted fluid, thereby automatically actuating the subset of
the plurality of flow control devices without further human
intervention or control.
10. A method according to claim 9 wherein the induced chemical is
encapsulated in a material that reacts or dissolves in the presence
of the unwanted fluid, and the encapsulating material can be
detected on the surface to indicate the location of production of
the unwanted fluid.
11. A wellbore penetrating a subterranean formation having a
plurality of flow control devices installed therein comprising: a
first flow control device installed in the wellbore being actuable
upon exposure to a first triggering chemical, but not upon exposure
to a second triggering chemical; and a second flow control device
installed in the wellbore being actuable upon exposure to the
second triggering chemical, but not actuable upon exposure to the
first triggering chemical.
12. A wellbore according to claim 11 further comprising a third
flow control device installed in a wellbore being actuable upon
exposure to a third triggering chemical, but not actuable upon
exposure to the first and second triggering chemicals.
13. A wellbore according to claim 11 wherein each flow control
device controls fluid flowing into the wellbore from a zone of the
subterranean formation, the flow control devices being arranged in
a series within a portion of the wellbore, and an introduced
triggering chemical flows to each of the flow control devices so as
to expose at least a portion of each flow control device to the
introduced chemical.
14. A wellbore according to claim 11 wherein the first flow control
device includes a mechanical stop retaining a choking member
actuated with one or more spring members, and the mechanical stop
is dissolvable by the first triggering chemical but not by the
second triggering chemical.
15. A wellbore according to claim 11 wherein the first triggering
chemical causes an exothermic chemical reaction within the first
flow control device.
16. A wellbore according to claim 11 wherein the first triggering
chemical causes the release of a plurality of sealing members that
seal one or more orifices in the first flow control device.
17. A wellbore according to claim 11 wherein the first triggering
chemical causes swelling of portions within the first flow control
device so as to restrict fluid flow within the first flow control
device.
18. A wellbore according to claim 11 further comprising a flowline
to the first and second flow control devices, the flowline being
separate from a production fluid flowline through which fluid
produced from the subterranean formation flows into the
wellbore.
19. A wellbore according to claim 11 wherein the first flow control
device is associated with a first chemical tracer material and the
second flow control device is associated with a second chemical
tracer material, the first and second tracer materials being
releasable in the presence of an undesirable fluid.
20. A wellbore according to claim 11 wherein the wellbore includes
a motherbore and a plurality of lateral wellbores branching from
the motherbore, and wherein the first and second flow control
devices are positioned within one of the lateral wellbores.
21. A wellbore according to claim 11 wherein the first triggering
chemical is located upstream from the first flow control device and
is automatically released in the presence of an unwanted fluid,
thereby automatically actuating the first flow control device
without human intervention or control.
22. A wellbore according to claim 21 wherein the first triggering
chemical is encapsulated in a material that reacts or dissolves in
the presence of the unwanted fluid and the encapsulating material
can be detected on the surface to indicate the location of the
production of the unwanted fluid.
23. A wellbore according to claim 11 wherein the first flow control
device includes an indicator chemical that is released into the
wellbore when the device is actuated, the indicator chemical being
detectable on the surface thereby indicating confirmation of
actuation of the device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/185,957, filed Jul. 19, 2011.
FIELD
[0002] This patent specification generally relates to downhole flow
control and injection devices. More particularly, this patent
specification relates to selective control of flow control and
injection devices installed in a wellbore using targeted
chemistry.
BACKGROUND
[0003] Intelligent and/or segmented completions such as staged
fracture completions and/or multi-zone injection wells have been
utilized quite extensively in the oilfield since the late 1990's.
Their application has become more widespread since the 2004 oil
price increase and worldwide technology acceptance. The main
applications in the Middle East for intelligent completions' have
been in controlling multi-lateral completions where each flow
control valve is placed at the junction for each lateral leg--often
an open hole lateral. These types of intelligent completion
applications allow a lateral to be choked back or shut-off should
unwanted production occur. This manipulation of the well completion
can be done without resorting to intervention through coiled tubing
or tractor operations which are themselves inherently risky
operations. Intelligent completions are conventionally operated by
use of hydraulic or electric control lines run in with the
completion, adding to the complexity of installation.
[0004] In parallel with this technology acceptance, passive inflow
control systems, (hereinafter referred to as "ICD"s) and/or
injection control systems have become extremely popular for
open-hole long horizontal completions especially in locations such
as in the Middle East carbonate reservoirs. The main drivers have
been controlling fracture contribution to the wellbore and
balancing for wellbore hydraulics effects in long horizontal or
deviated wells.
[0005] In addition selective segmented completions have been used
widely to facilitate the stimulation treatment of multi-zone and/or
long horizontal wells. In this case, the selectivity is provided by
a series of valves that is actuated to direct stimulating fluids
(acid, water, sand, proppant, polymer, solvents or other such
fluids) for the purpose of selectively injecting into the specific
segment of the well being targeted.
[0006] The ICD style of completion is often particularly attractive
to the operator and especially the drilling departments due to the
relatively low risk and cost of the installation phase. However the
long-term benefits of the passive inflow control completion system
are compromised should water production enter the wellbore. The ICD
will limit the production of water, but does not allow it to be
effectively shut off without intervention. Similarly, current ICD
type completions complicate access to the formation for treatments
such as stimulation treatments, clay stabilization, water
conformance injection etc.
[0007] In addition, an ICD is by default designed before
installation phase. Once the ICD is in place, there is little
chance to change its characteristics (flow versus pressure
differential), and therefore their success relies on the accurate
characterization of the formation conductivity with the
borehole.
[0008] Attempts have been made to provide dissolvable members.
Commonly-assigned U.S. Patent Application Publ. No. US2007/0181224
discusses reactive alloy materials for targeted control. One
composition consists essentially of one or more reactive metals in
major proportion, and one or more alloying elements in minor
proportion, with the provisos that the composition is
high-strength, controllably reactive, and degradable under defined
conditions. Compositions may exist in a variety of morphologies,
including a reactive metal or degradable alloy processed into an
alloy of crystalline, amorphous or mixed structure that may
constitute the matrix of other compositions, for instance a
composite.
[0009] Other attempts have been made to provide dissolvable members
to control downhole fluid flow in oilfield applications. For
example, commonly-assigned U.S. Patent Application Publ. No.
2009/0151949 discusses self dissolvable alloys for perforating.
U.S. Patent Application Publ. No. 2004/0014607 discusses
dissolvable encapsulation of chemicals for oilfield treatment
purposes. Commonly-assigned U.S. Patent Application Publ. No.
2011/0067889 discusses a hydraulic regulating mechanism for
disposal in a well. The mechanism includes a degradable metal based
element and a swellable component for hydraulic regulation. The
mechanism is configured for ease of setting and removal by allowing
degrading of the metal based element upon exposure to certain
downhole conditions which may trigger shrinking of the swellable
component. Commonly-assigned U.S. Patent Application Publ. No.
2011/0048743 discusses a dissolvable bridge plug configured with
components for maintaining anchoring and structural integrity for
high pressure applications. Embodiments of the plug are configured
such that these components may substantially dissolve to allow for
ease of plug removal following such applications. Commonly-assigned
U.S. Patent Application Publ. No. 2008/0210423 discusses circulated
degradable material assisted diversion methods for well treatment
in completed wells. Commonly-assigned U.S. Patent Application Publ.
No. 2008/0105438 discusses whipstocks and deflectors comprising a
degradable composition.
[0010] All of the commonly-assigned patent applications identified
above are hereby incorporated by reference herein.
SUMMARY
[0011] According to some embodiments, a method of chemically
targeting control of flow control devices installed in a wellbore
is provided. The method includes introducing a chemical into a
wellbore having a plurality of flow control devices installed
therein; and causing actuation of a subset of the plurality of flow
control devices with a chemical reaction due to the presence of the
introduced chemical at the flow control device. According to some
embodiments, at least one flow control device is an inflow control
device that controls fluid flowing into the wellbore from a zone of
the subterranean formation. According to some other embodiments, at
least one flow control device is an injection flow control device
that controls fluid flowing from the wellbore into a zone of the
subterranean formation. The flow control devices can be arranged in
a series within a portion of the wellbore, and the introduced
triggering chemical flows to each of the flow control devices so as
to expose at least a portion of each flow control device to the
introduced chemical.
[0012] According to some embodiments, the triggering chemical
dissolves a mechanical stop retaining a choking member actuated
with one or more spring members. According to some other
embodiments, the introduced chemical causes an exothermic chemical
reaction used to actuate a choking member. According to some other
embodiments, the introduced chemical reacts with a material in the
flow control device so as to release a plurality of sealing members
that seal one or more orifices in a flow control device. According
to some other embodiments, the introduced chemical causes swelling
of portions within the flow control device so as to restrict fluid
flow within the flow control device.
[0013] According to some embodiments a separate flowline can be
provided to deliver the introduced chemical flows to each flow
control device. According to some embodiments, chemical tracers can
be used that are associated with each flow control device and are
released upon exposure to an undesirable fluid so that
identification on the surface of the tracer can be used to indicate
which flow control device should be actuated so as to reduce the
amount of the undesirable fluid entering the wellbore.
[0014] According to some embodiments, a wellbore penetrating a
subterranean formation having a plurality of flow control devices
installed therein is provided that includes a first flow control
device installed in the wellbore being actuable upon exposure to a
first triggering chemical, but not upon exposure to a second
triggering chemical; and a second flow control device installed in
the wellbore being actuable upon exposure to the second triggering
chemical, but not actuable upon exposure to the first triggering
chemical.
[0015] According to some embodiments, the triggering chemical is
encapsulated in a material and is positioned upstream from the flow
control device. The encapsulating material dissolves or reacts with
an unwanted fluid so as to release the triggering chemical and
automatically actuate the flow control device. The encapsulating
material can also contain a tracer that is detectable on the
surface so as to indicate the location of the source of the
unwanted fluid. According to some embodiments an indicator chemical
is provided that is released only upon actuation of the flow
control device, thereby indicating or confirming to an operator on
the surface that actuation of the device has occurred.
BRIEF DESCRIPTION OF THE FIGURES
[0016] The present disclosure is further described in the detailed
description which follows, in reference to the noted plurality of
drawings by way of non-limiting examples of embodiments, in which
like reference numerals represent similar parts throughout the
several views of the drawings, and wherein:
[0017] FIG. 1 illustrates an oilfield setting in which chemically
targeted control of downhole flow control devices is carried out,
according to some embodiments;
[0018] FIGS. 2A-C are quarter cut-away side-views showing some
components of a system for targeted control of downhole flow
control devices, according to some embodiments;
[0019] FIGS. 3A-E illustrate the principle of activation for a
control line system, according to some embodiments;
[0020] FIGS. 4A-E illustrate the principle of activation for a
tubing bullhead based system, according to some embodiments;
[0021] FIGS. 5A-B illustrate a flow control device having
releasable sealing balls, according to some embodiments;
[0022] FIGS. 6A-B illustrate a flow control device having a chamber
with a material that swells when in contact with a trigger
chemical, according to some embodiments;
[0023] FIGS. 7A-B illustrate a flow control device having a choke
sleeve controlled by an exothermic chemical reaction, according to
some embodiments;
[0024] FIGS. 8A-E are diagrams representing a basic horizontal well
system using chemically targeted flow control devices, according to
some embodiments;
[0025] FIG. 9 illustrates using chemically targeted flow control
devices in a multi-lateral application with a non-intelligent
motherbore completion according to some embodiments;
[0026] FIG. 10 illustrates using chemically targeted flow control
devices in a multi-lateral application with an intelligent
motherbore completion, according to some embodiments;
[0027] FIG. 11 illustrates using chemically targeted flow control
devices in a multi-lateral application with a horizontal
motherbore, according to some embodiments;
[0028] FIG. 12 is a table that presents selected examples chemicals
that can be used to provide selective triggering, according to some
embodiments;
[0029] FIG. 13 illustrates an injection flow control device,
according to some embodiments;
[0030] FIGS. 14A-B are quarter cut-away side-views showing some
components of a downhole flow control device having an indicator
chemical released to confirm device actuation, according to some
embodiments; and
[0031] FIGS. 15A-B are quarter cut-away side-views showing some
components of downhole flow control devices having self-triggering
capability, according to some embodiments.
DETAILED DESCRIPTION
[0032] The following description provides exemplary embodiments
only, and is not intended to limit the scope, applicability, or
configuration of the disclosure. Rather, the following description
of the exemplary embodiments will provide those skilled in the art
with an enabling description for implementing one or more exemplary
embodiments. It being understood that various changes may be made
in the function and arrangement of elements without departing from
the scope of subject disclosure as set forth in the appended
claims.
[0033] Specific details are given in the following description to
provide a thorough understanding of the embodiments. However, it
will be understood by one of ordinary skill in the art that the
embodiments may be practiced without these specific details. For
example, systems, processes, and other elements in the subject
disclosure may be shown as components in block diagram form in
order not to obscure the embodiments in unnecessary detail. In
other instances, well-known processes, structures, and techniques
may be shown without unnecessary detail in order to avoid obscuring
the embodiments. Further, like reference numbers and designations
in the various drawings indicate like elements.
[0034] Also, it is noted that individual embodiments may be
described as a process which is depicted as a flowchart, a flow
diagram, a data flow diagram, a structure diagram, or a block
diagram. Although a flowchart may describe the operations as a
sequential process, many of the operations can be performed in
parallel or concurrently. In addition, the order of the operations
may be re-arranged. A process may be terminated when its operations
are completed, but could have additional steps not discussed or
included in a figure. Furthermore, not all operations in any
particularly described process may occur in all embodiments. A
process may correspond to a method, a function, a procedure, a
subroutine, a subprogram, etc. When a process corresponds to a
function, its termination corresponds to a return of the function
to the calling function or the main function.
[0035] Furthermore, embodiments of the subject disclosure may be
implemented, at least in part, either manually or automatically.
Manual or automatic implementations may be executed, or at least
assisted, through the use of machines, hardware, software,
firmware, middleware, microcode, hardware description languages, or
any combination thereof. When implemented in software, firmware,
middleware or microcode, the program code or code segments to
perform the necessary tasks may be stored in a machine readable
medium. A processor(s) may perform the necessary tasks.
[0036] According to some embodiments, an enhanced flow control
device is provided, that can be selectively closed completely or
have its effective flow area reduced to restrict production (or
injection) by use of a chemical trigger mechanism. In addition,
some of the systems described herein deploy specific targeted
chemical tracers, dissolvable in the unwanted production fluid
(e.g. water or gas). These chemical tracers once dissolved will
enter the production stream and be identified at the surface. The
identification will determine which segment of the completion is
producing the unwanted fluid.
[0037] According to some embodiments, an appropriate chemical
trigger is placed, for example, by pumping down through the tubing
and utilizing intelligent completion valve to place the chemical,
or by spotting with coiled tubing and bullhead to the formation, or
by other methods of chemical placement. The chemical trigger will
only trigger the active chemical in the appropriate flow control
device. This chemical will then change state--dissolve, create
thermal reaction, create a pressure swell or expand--which in turn
allows a mechanical device to shift position such that a valve in
the flow control device closes, or reduces its flow by restricting
the flow area by swelling/expansion of the active chemical.
[0038] Several designs have being proposed that make a flow control
device react automatically to produced water and/or gas (unwanted
fluids) to shut off or restrict the flow from the given zone.
However, such designs do not provide any downhole information and
due to the lack of downhole control, produced fluids can migrate
from one segment to the other causing the wrong zones of the
wellbore to shut off. Furthermore, the designs are fixed at the
time of installation and do not allow the operator the choice to
make a decision on how or which segment of the well can be modified
after the completion is installed in the wellbore.
[0039] In contrast, according to some embodiments, the techniques
described herein allow the operator to determine where unwanted
fluids are coming from and react to those fluids by making a
conscious decision to pump the required chemical trigger for the
section of the well producing unwanted fluids to shut it off, or
restrict its flow.
[0040] According to some embodiments the same type of chemical
trigger mechanism is used to open instead of shut a device, or
adjust an injection valve characteristics without intervening in
the wellbore.
[0041] The devices described herein have particular application
where it is very risky or impossible to enter the wellbore with
coiled tubing or tractors--i.e. extended reach wells, long
horizontals, or multilateral legs out from the motherbore.
Conventional technology allows completion tubular and Inflow
Control Devices (ICD's) to be run and dropped off in open hole
lateral legs across from the motherbore, but so far there are
limited ways to re-enter these laterals once completed and involve
inherently risky intervention.
[0042] According to some embodiments, the devices described herein
can be run stand-alone as a passive component (with the chemical
trigger as an option) or run in combination with an intelligent
motherbore completion affording more production sweep control into
the wellbore.
[0043] According to some embodiments, a chamber that is made of
acid soluble material such as carbonate rock is installed in a well
section. The chamber contains pre-sized balls that can be released
to plug the flow port of the flow control device. The release of
the balls is done by injecting an acid that dissolves the chamber.
Other materials that can be used for the construction of the
chamber include plastic, organic and inorganic compounds that can
be dissolved by specific fluids.
[0044] According to some other embodiments, an acid soluble
material such as carbonate rock is used for the cap/stopper of a
spring loaded valve. The valve is set to be normally open when the
cap is in place by compressing the spring. An acid can be injected
when desired to dissolve the cap/stopper and release the spring
such that the valve will be in a closed position. According to some
embodiments, the valve is set to be normally closed when the cap is
in place by compressing the spring. An acid can be injected when
desired to dissolve the cap/stopper and release the spring such
that the valve will be in an open position.
[0045] According to some other embodiments, a chamber is attached
to the flow control device, or the chamber can be an integrated
part of the flow control device. The chamber may be made of
material that can be dissolved by specific fluids such as acid. The
chamber may contain a chemical or chemicals that swell when
reacting with a specific injection fluid. As the material in the
chamber swell, it fills and seals the chamber such that the valve
is effectively shut. The swelling of the material in the chamber
can be triggered by fluid adsorption, heat, or chemical
reaction.
[0046] According to some other embodiments, a chamber resin, wax,
or other materials with melting higher than the reservoir
temperature is used. According to some embodiments, an exothermic
reaction can be created by the reaction between the injection fluid
and the chamber to cause temperature increase beyond the melting of
the filling materials in the chamber, such as resin. The melted
material will fill the fluid flow path, and solidify when the
exothermic reaction ceases, to plug off the flow ports or valves.
The flow ports or valves can be unplugged when pumping heated fluid
to melt the solidified material.
[0047] According to some other embodiments a single layer or
multiple layers of encapsulated catalysts embedded in resin fluids
are used, which release after the injection of certain solvents, to
dissolve the encapsulated layer. The released catalysts will allow
resins curing to solidify which can block a flowing channel.
[0048] According to some other embodiments, the exothermic chemical
reactions are used to significantly increase the initial internal
volume. A valve can be coupled to a reaction chamber to shut down
by expansion.
[0049] According to some other embodiments, a flow control device
has a chamber containing mixed base-gel fluid, such as a guar-gel
system or surfactants. After injecting a metallic salt-crosslinker,
a high viscous material is created to block the flow channels. This
system is also reversible. This high viscosity gel is degradable by
injecting oxidizers. In other words, the closed channels can be
re-opened.
[0050] According to some other embodiments, a screen flow control
device is used which contains a mixture of a chemical or chemicals.
After injection with another mixture of a chemical or chemicals, it
will produce a lot of precipitates which reduce or block the screen
flow control device.
[0051] According to some other embodiments, a "hydrogel" is used
which can be swelled or de-swelled using a range of different
triggers such as pH, ionic strength, temperature and
electromagnetic radiation.
[0052] According to some embodiments, the placement of the chemical
can be through simple bullheading from the surface through the
tubing, through coiled tubing to spot it at the nearest appropriate
location or through chemical injection control lines run with the
completion.
[0053] According to some embodiments, the flow path connected to
the valve or flow control device contains a permeable porous
medium. The porous media can be blocked when desired by injecting a
cake forming slurry containing fine particulates or/and fibers, or
chemicals that react with the porous medium to form precipitants
which seal off the porous medium. Reversely, the flow capacity of
the porous medium can be enhanced by injecting a chemical that
dissolve portions of the pore network.
[0054] FIG. 1 illustrates an oilfield setting in which chemically
targeted control of downhole flow control devices is carried out,
according to some embodiments. On the surface 110, is a coiled
tubing truck 120 located at a wellhead 112. A chemical tank 104,
hold fluid which is being introduced into the wellbore 116 through
the tubing 124. Tubing 124 enters wellbore 116 via well head 112.
At or near the lower end of tubing 124 is a bottom hole assembly
(BHA), not shown.
[0055] A barefoot section 130 of wellbore 116 is shown having
several producing zones. Each producing zone of the wellbore is
hydraulically isolated using a number of packers, such as packers
126 and 128 which are used to isolate zone 132. Within each zone, a
flow control device 136 is used to allow fluid to enter production
tubing. A chemical tracer 134 is provided to indicate the
production of undesirable fluid from the zone 132, which can be
detected and identified on the surface 110. The flow control
devices such as device 136 can be selectively closed using a
chemical introduced from truck 120, as will be described in greater
detail herein.
[0056] Data from truck 120 or otherwise gathered at the wellsite
are transmitted to a processing center 150 which includes one or
more central processing units 144 for carrying out the data
processing procedures as described herein, as well as other
processing. Processing center 150 also includes a storage system
142, communications and input/output modules 140, a user display
146 and a user input system 148. According to some embodiments,
processing center 150 may be located in a location remote from the
wellsite.
[0057] FIGS. 2A-C are quarter cut-away side-views showing some
components of a system for targeted control of downhole flow
control devices, according to some embodiments. In FIG. 2A, packer
devices 210 and 212 can be mechanical, hydraulic, hydrostatic or
swell packers, and are set across a segment in the wellbore. Note
that the wellbore can be a cased hole perforated or open hole
wellbore. The packers 210 and 212 provide effective hydraulic
isolation between segment 214 and other producing segments, such as
neighboring segment 216.
[0058] Inflow Control Devices (ICD) 220 and 222 can be either choke
based, or in conjunction with a spring allowing for a range of
activation. Each ICD device provides the necessary choking of the
fluid flow to restrict production into the wellbore from the
formation or injection out of a wellbore into the formation. In
FIG. 2A, the ICD 220 restricts production into flow line 202 from
segment 214, and ICD 222 restricts production into flow line 202
from segment 216. Each ICD includes one or more chokes, which
control the flow through the ICD. This choke may be of variable or
fixed nature. The variable choke design is likely to be controlled
by spring mechanical or hydraulic forces against a piston exposed
to the upstream fluid. In the case of FIGS. 2A-B, choke orifices
such as 224a, 224b and 224c are spaced apart around the
circumference of the ICD 220. Choke sleeve 226 of ICD 220 is a
sleeve that shifts over the chokes when activated and either closes
off or restricts the fluids flow through the ICD.
[0059] Chemical tracers 228 and 230 are provided for isolated
segments 214 and 216 respectively. The tracer technology is
existing, and is a water or gas soluble chemical, which has a
specific chemistry (sometimes referred to as a "DNA chemical
tracer" even though real DNA is not identified). Tracers such as
228 and 230 are placed at different positions in the wellbore
completion. Each position has a different, unique tracer chemical.
Once the unwanted fluid passes into the wellbore, the tracer in
that segment of the wellbore only is dissolved and the chemicals
can be detected and analyzed at surface. This will tell the
operator which section of the wellbore the water or gas is coming
from.
[0060] A mechanical stop device is built into each ICD and acts as
a stopper for a piston or other moving part. In FIG. 2B, stop
device 244 of ICD is a ring of material that acts as a stopper for
choke sleeve 226 which is urged to towards the left by a coiled
spring 240. The mechanical stop device 224 is retained in place or
made of a chemical that is designed to change its state when
contacted with a "trigger" chemical or catalyst. Once triggered
this stop device will either dissolve, react, create pressure or
temperature, or expand to allow a mechanical device (a piston or
other such device) to move to a position where it either shuts in
the choke, or restricts the size of the choke. In the case of FIGS.
2A-C, stop device 244 dissolves so that it no longer retains the
choke sleeve 226 from moving to shut off the choke orifices.
[0061] A chemical trigger is a specific chemical designed to be
pumped downhole and will react only with the targeted mechanical
stop device as described above. The trigger may be an acid, a
solvent, a catalyst or other chemical designed which is able to
withstand the pumping operation to place it in the wellbore or the
wellbore conditions, and also avoids damaging the formation.
Ideally this chemical should be limited in volume to reduce
unnecessary pumping or placement issues. In FIG. 2C, the trigger
chemical that is specific to the stop device 244 has dissolved the
stop device and as a result the choke sleeve 226 is urged to the
left by coil spring 240 and covers the choke orifices such as
orifices 224a, 224b and 224c.
[0062] There are numerous examples of chemicals that could provide
the described "selective triggering" functionality. FIG. 12 is a
table that presents selected examples chemicals that can be used to
provide selective triggering, according to some embodiments. Table
1 lists several examples of "Base material"--which could be used in
solid form--along with an example "trigger solvent" either
non-polar, aprotic or polar protic. Table 1 provides examples of
which base materials are best suited for deployment for selective
triggering in a downhole completion environment. The following
abbreviations are used for Table 1:
[0063] Y Base material is soluble in the solvent
[0064] PY Partially soluble in the solvent
[0065] N Base material is insoluble in the solvent
[0066] HT High Temperature
[0067] Polymers
[0068] PS polystyrene
[0069] PE polyethylene
[0070] HDPE High density polyethylene
[0071] LDPE Low density polyethylene
[0072] PVC polyvinyl chloride
[0073] PET Polyethylene terephthalates
[0074] PC Polycarbonate
[0075] PVDF Polyvinylidene Fluoride
[0076] Solvents
[0077] THF Tetrahydrofuran
[0078] DMF Dimethylformamide
[0079] DMAC Dimethylacetamide
[0080] TCB 1,2,4-trichlorobenzene
[0081] ODCB orthodichlorobenzene
[0082] DEE Diethyl ether
[0083] C-hexane Cyclohexane
[0084] DCM Dichloromethane
[0085] DMF Dimethylformamide
[0086] m-Cresol 3-methylphenol
[0087] DMSO Dimethyl sulfoxide
[0088] HCl Hydrochloric acid
[0089] HNO.sub.3 Nitric acid
[0090] The examples listed in Table 1 is not an exhaustive list,
but rather are examples to provide a basis for one skilled in the
art to select specific chemical "pairs" allowing this selectivity
in triggering them to a different state. For example, one could use
solid piece of carbonate rock as a stop device. This piece of
carbonate can be dissolved by many kinds of inorganic and organic
acids; such as HCl, H.sub.2SO.sub.4, HNO.sub.3, CH.sub.3COOH, HCOOH
etc. Other alternatives include the use of a piece of solid
polystyrene which can be dissolved by acetone. A further examples
is to utilise a piece of solid polyvinyl chloride (PVC) which can
be dissolved by tetrahydrofuran.
[0091] FIGS. 3A-E illustrate the principle of activation for a
control line system, according to some embodiments. Two zones 310
and 312 are illustrated to show the principle when water or other
unwanted production fluid enters the production stream. In these
examples it is assumed that oil is the production fluid, and water
is the fluid to be controlled. Packers 330 and 332 are used to
hydraulically isolate the zones 310 and 312. Fluid from zone 310
enters the flow line 302 via ICD 320 and fluid from zone 312 enters
via ICD 322. In FIG. 3A, both zones 310 and 312 are producing oil,
as shown by the solid arrows, through inflow control devices to
balance or passively control production inflow. In FIG. 3A, all
zones are producing into the wellbore.
[0092] In FIG. 3B, zone 310 is producing water, as denoted by the
broken-line arrows. Tracers 340 and 342 are soluble to water, since
water is the undesirable fluid in this example. Tracer 340
therefore dissolves in water and enters the production stream as
denoted by droplets 340a. Sampling of the fluids is done at surface
to determine which tracer is being produced and therefore
identifying that zone 310 is the water source.
[0093] In FIG. 3C, a trigger chemical is selected to activate ICD
320 in zone 310 only. This chemical will not affect the ICD 322 in
zone 312 or ICD's located other zones. Trigger chemical can be
spotted by bullheading, manipulation of control valves or spotting
via coiled tubing and pumped through the control line bypassing the
segment packer and supplies the chemical directly to the inflow
control devices. In the case of FIGS. 3A-E, a control line 350 is
used that bypasses the packers. In FIG. 3D the trigger chemical
reacts with a specific chemical in ICD 320 and allows ICD 320 to
activate. This could be for example, by dissolving a mechanical
stop device, as shown in and described with respect to FIGS. 2A-C.
ICD 320 activates to close off flow port in ICD 320. Zone 310 is
now isolated, while zone 312 is still able to produce. In FIG. 3E,
the well is put back on production. Zone 310 is isolated, and zone
312 is still able to produce through inflow control device 322. The
well now produces with lower water cut until such time as water
encroaches wellbore at different position in reservoir.
[0094] FIGS. 4A-E illustrate the principle of activation for a
tubing bullhead based system, according to some embodiments.
Although simpler to deploy mechanically than a control line system
as shown in FIGS. 3A-E, the option shown in FIGS. 4A-E use more
chemicals and fluids for triggering, and potentially result in more
fluids being bullheaded into the formation. Care should be taken
with this option to ensure the fluid reaches all segments. If any
segment allows too much fluid into it, it is possible that the
chemical trigger will not reach segments further down the wellbore
or lateral and therefore not activating the appropriate segment
isolation mechanism. Two zones 410 and 412 are illustrated to show
the principle when water or other unwanted production fluid enters
the production stream. Packers 430 and 432 are used to
hydraulically isolate the zones 410 and 412. Fluid from zone 410
enters the flow line 402 via ICD 420 and fluid from zone 412 enters
via ICD 422. In FIG. 4A, both zones 410 and 412 are producing oil,
as shown by the solid arrows, through inflow control devices to
balance or passively control production inflow. In FIG. 4A, all
zones are producing into the wellbore.
[0095] In FIG. 4B, zone 410 is producing water, as denoted by the
broken-line arrows. Tracers 440 and 442 are soluble to water, since
water is the undesirable fluid in this example. Tracer 440
therefore dissolves in water and enters the production stream as
denoted by droplets 440a. Sampling of the fluids is done at surface
to determine which tracer is being produced and therefore
identifying that zone 410 is the water source.
[0096] In FIG. 4C, a chemical trigger is selected to activate ICD
420 in zone 410 only. This chemical will not affect the ICD 422 in
zone 412 or ICD's located other zones. The trigger chemical is
spotted by bullheading, manipulation of control valves or spotting
via coiled tubing and pumped through the tubing and bullheads
through the inflow control devices. In FIG. 4D the trigger chemical
reacts with a specific chemical in ICD 420 and allows ICD 420 to
activate. This could be for example, by dissolving a mechanical
stop device, as shown in and described with respect to FIGS. 2A-C.
ICD 420 activates to close off flow port in ICD 420. Zone 410 is
now isolated, while zone 412 is still able to produce. In FIG. 4E,
the well is put back on production. Zone 410 is isolated, and zone
412 is still able to produce through inflow control device 422. The
well now produces with lower water cut until such time as water
encroaches wellbore at different position in reservoir.
[0097] Further detail regarding various activation and operating
options will now be provided, according to some embodiments. Many
options exist for the activation and chemical--mechanical mechanism
to isolate the production.
[0098] Acid Soluble Cap/Stopper. According to some embodiments, the
mechanical stop shown in FIGS. 2B-C is an example where an acid
soluble material such as carbonate rock can be used as a cap or
stopper of a spring loaded valve. The valve is set to be normally
open when the cap is in place by compressing the spring. An acid
can be injected when desired to dissolve the cap/stopper and
release the spring such that the valve will be in a closed
position.
[0099] Acid Soluble Material in Chamber. FIGS. 5A-B illustrate a
flow control device having releasable sealing balls, according to
some embodiments. Flow control device 500 has a cylindrical body
through which fluid produced from the production zone can flow into
a production tubing 502. The produced fluid flows through an
orifice plate 512 that includes a number of uniformly sized
orifices. Flow control device 500 is installed into a well section,
and includes an annular chamber 510 that is made of an acid soluble
material such as carbonate rock. The chamber 510 contains pre-sized
balls 520 that can be released to plug the orifices in plate 512 of
the flow control device 500. According to some embodiments a
control line 540 is used to direct the triggering chemical directly
to the chamber 510. According to other embodiments, the triggering
chemical can be bullheaded as described with respect to FIGS. 4A-E.
According to some embodiments, the release of the balls 520 is done
by injecting an acid that dissolves the chamber. According to other
embodiments, other materials can be used for the construction of
the chamber including plastic, organic and inorganic compounds that
can be dissolved by specific fluids. In FIG. 12, Table 1 gives a
number of alternative options of chemicals that could be deployed
for such a purpose. Examples include a chamber made in aluminium
and dissolved by acid such as HCl. Polyvinyl chloride chamber is
resistant to HCl, but can be dissolved by Tetrahydrofuran solvent.
Polyethylene terephthalate chamber is soluble in phenol,
chlorophenol, nitrobenzene and dimethyl sulphoxide. It is insoluble
in ether and in most other organic solvents.
[0100] FIG. 5B shows the flow control device 500 after the sealing
balls have been released and are sealing the orifices on plate 512.
According to some embodiments, chamber 510 can contain a material
having a low melting point and the triggering chemical can be
designed to cause an exothermic chemical reactions, as is discussed
in further detail below.
[0101] Chamber Soluble to Specific Trigger Chemicals or Catalysts.
FIGS. 6A-B illustrate a flow control device having a chamber with a
material that swells when in contact with a trigger chemical,
according to some embodiments. Flow control device 600 has a
cylindrical body through which fluid produced from the production
zone can flow into a production tubing 602. The produced fluid
flows through the center surrounded by an annular chamber or region
610 that contains a chemical or chemicals that will swell when
reacting with a specific injection fluid. The triggering fluid can
be directed to the chamber 610 via a control line 640 or it can be
bullheaded as is described with respect to FIGS. 4A-E. As the
material in the chamber 610 swells, it fills and seals the chamber
such that the valve is effectively shut, as shown in FIG. 6B. The
swelling of the material in the chamber 610 can be triggered by
fluid adsorption, heat, or chemical reaction. According to some
embodiments, the chamber can be made of material that can be
dissolved by specific fluids such as acid. Referring to FIG. 12,
Table 1 lists potential chemical pairs--base and trigger--that
could be deployed for these examples.
[0102] Chamber with Material with Low Melting Point. Similar to the
embodiments described with respect to FIGS. 6A-B, according to some
embodiments a resin, wax, or other materials with melting higher
than the reservoir temperature in the chamber is used. An
exothermic reaction can be created by the reaction between the
injection fluid and the chamber to cause temperature increase
beyond the melting of the filling materials in the chamber, such as
resin. The melted material will fill the fluid flow path, and
solidify when the exothermic reaction ceases, to plug off the flow
ports or valves. The flow ports or valves can be unplugged when
pumping heated fluid to melt the solidified material. According to
some embodiments, the material melting can be used to release
sealing balls or other particles, such as described with respect to
FIGS. 5A-B. Table 1 of FIG. 12 lists potential chemical pairs--base
and trigger--that could be deployed for these examples.
[0103] Single or Multiple Layer Catalysts. According to some
embodiments, a single layer or multiple layers of an encapsulated
catalysts, are embedded in resin fluids which release after
injecting certain solvents to dissolve the encapsulated layer. The
released catalysts will allow resins to cure into a solid which can
block a flowing channel. Thus, by using encapsulation, the number
of uniquely "addressable" or individually targeted flow control
devices or zones can be effectively increased, given a set number
of chemical reactions. Table 1 in FIG. 12 lists potential chemical
pairs--base and trigger--that could be deployed as encapsulated
solids or fluids. After the encapsulation is destroyed due to
contact with a trigger chemical, the chemical within is released
and can perform the function herein. One example is Epoxy Resin, in
order to convert epoxy resins into a hard material, it is necessary
to cure the resin with hardener (catalyst). Epoxy resins cure
quickly and easily at practically any temperature from
5-150.degree. C. depending on the choice of hardener. The hardeners
for epoxies include amines, polyamides, anhydrides, isocyanates,
etc. For instance, anhydride can be encapsulated by polystyrene,
and embedded in the epoxy resin. If it is desirable to release
anhydride, acetone can be pumped to dissolve the encapsulated
layer. The released anhydride will be dispersed into epoxy resin,
and allowed to cure into a solid.
[0104] Exothermic Reactions. Exothermic chemical reactions can be
used to significantly increase an initial internal volume in for
example, an enclosed chamber. A valve can be coupled to the
reaction chamber to shut down by the expansion. FIGS. 7A-B
illustrate a flow control device having a choke sleeve controlled
by an exothermic chemical reaction, according to some embodiments.
ICD 720 includes a number of choke orifices such as orifices 724a,
724b and 724c trough which fluid from the formation can enter the
production tubing 702. A choke sleeve 726 can slide over the
orifices to shut off fluid flow, under the control of a triggering
chemical. A piston 744 is actuated by an exothermic chemical
reaction in chamber 740. The exothermic reaction causes the choke
sleeve 726 to slide to the left so as to shut off fluid flow
between the formation and tubing 702, as shown in FIG. 7B. Note
that according to some embodiments, exothermic chemical reactions
can be used to melt material for use in devices such as described
with respect to FIGS. 6A-B and FIGS. 5A-B.
[0105] According to some embodiments the ICD 720 is a pneumatically
operated valve, and the introduced triggering chemical causes a
reaction to generate gas that actuates the pneumatic valve.
Examples of gas generating reactions include acid (organic acids
such as formic and acetic acid, or inorganic acids such as
hydrochloric acid or nitric acid) reacting with sodium carbonate,
sodium bicarbonate, or calcium carbonate; sodium nitride
(NaNO.sub.2) reacting with sulfamic acid (HSO.sub.3NH.sub.2).
[0106] Mixed Base-Gel Fluid. According to some embodiments, a flow
control device can be combined with a chamber that contains mixed
base-gel fluid, such as a guar-gel system or surfactants. After
injecting typically a metallic salt-crosslinker, a highly viscous
material is created to block the flow channels. This system is also
reversible. This high viscosity gel will be degradable by injecting
oxidizers. In other words, the closed channels can be
re-opened.
[0107] Further detail will now be provided for system architectures
associated with chemically targeted control of flow control
devices, according to some embodiments. Many options exist for
incorporation of the techniques described herein into a completion,
from simple to highly complex integrated completions.
[0108] FIGS. 8A-E are diagrams representing a basic horizontal well
system using chemically targeted flow control devices, according to
some embodiments. The upper completion 810 is illustrated as a
simple tubing plus production packer, but could be any upper
completion, either run separately or in conjunction with the lower
completion.
[0109] The lower completions 820 and 822 are shown in FIGS. 8A and
8C respectively, and share a number of components in common. FIG.
8B show detail for region 830 in completion 820, while FIGS. 8D and
8E show detail for regions 840 and 850 respectively in completion
822. Isolation packers such as 812 and 814 are used to
hydraulically isolate adjacent segments. Note that the lower
completions 820 and 822 can be open hole or cased hole. For each
isolated segment, an inflow control device (ICD) is provided such
as ICDs 832, 834 and 828 in FIGS. 8A and 8B, and ICDs 842, 844, 852
and 853 in FIGS. 8C, 8D and 8E. The inflow control devices each
contain a mechanism to close or significantly reduce the flow area
when triggered with a "trigger chemical" as described herein. Sand
screens such as screens 854 and 856 in FIG. 8E are optionally
provided, for example in completions requiring sand control, in
conjunction with the system architectures shown. A flowing fluid
"detector"--a tracer chemical placed in each isolated segment
completion device that is soluble in a specific target fluid phase
(e.g. water or gas), for example, tracer chemicals 836 and 838 are
shown in FIG. 8B, and tracer chemicals 846 and 848 are shown in
FIG. 8D. Once that fluid phase starts to produce into the wellbore,
the tracer will slowly dissolve into the production stream and be
detected at surface by chemical analyses.
[0110] In the case of completion 820 shown in FIG. 8A, the "trigger
chemical" or catalyst is pumped downhole by bullheading through the
completion tubing 802 to all the inflow control devices in the
lateral section. The pumped chemical preferably contacts each and
every one of the inflow control devices in order to activate the
target device. As such it is expected that larger fluid volumes
would be used. In addition, this option would obviate or make more
complicated the use of check valves in each of the inflow control
devices.
[0111] FIG. 8C highlights an alternative and more economical system
option, according to some embodiments, whereby the trigger chemical
is bullheaded from surface or spotted just above the lower
completion via coiled tubing. Once the triggering chemical reaches
the upper segment the chemical being pumped will bypass through the
control line 842 which passes each and everyone of the inflow
control valves. The trigger chemical or catalyst thus passes each
of the valves. Only the target valve is activated by the
pre-determined chemical reaction. The option shown in FIG. 8C
reduces the amount of trigger chemical required reducing potential
formation damage making it more efficient, and allows the inflow
control valves to contain a flow check mechanism eliminating
wellbore cross-flow.
[0112] FIGS. 9-11 illustrate multilateral completions using
chemically targeted flow control devices, according to some
embodiments. A significant advantage of utilizing chemical
catalysts or "triggers" to activate a mechanical or hydraulic
device, such as the inflow control devices described herein, is
that it can be spotted and pumped easily into complex wellbores,
such as multi-laterals. Intelligent completions in the motherbore
(see FIGS. 10 and 11) can be combined with chemically activated
lateral sections to allow a flexible, yet relatively simple design
in getting fluid sensitivity and a measurement of segmented control
into difficult to intervene lateral sections.
[0113] A chemically activated multilateral completion can also be
designed without a need for intelligent completion components, for
example as in FIG. 9, which illustrates using chemically targeted
flow control devices in a multi-lateral application with a
non-intelligent motherbore completion according to some
embodiments. In certain circumstances, where chemical triggers can
be spotted at the appropriate lateral junction by coiled tubing or
bullheading from surface to all lateral legs at the same time. In
FIG. 9, the motherbore 910 is completed with a single packer 900.
Multiple lateral wellbores branch off of motherbore 910 of which
three are shown 920, 922 and 924. Each lateral can be completed
with casing, or openhole, as shown, as a perforated cased lateral,
or as a combination of the two. Each lateral includes a number of
packers that are used to hydraulically isolate production zones
within the subterranean formation. Each isolated zone preferably
includes a flow control device having both a chemical tracer and
chemically triggered control of the flow, using one or more of the
techniques described herein. For example, in lateral 920, packers
912 and 914 are used to isolate a zone 916 of the formation for
production into tubing 904. The flow of fluid from the formation
zone 916 into the tubing 904 is controlled using a flow control
device 918 which preferably includes a chemical tracer sensitive to
unwanted fluid, and a chemically activated shut-off means such as
described herein. The triggering chemical can be delivered using a
control line 930 as shown, or it can be delivered through the
production tubing 904. Some or all of the flow control devices can
also be equipped with sand screens such as shown with flow control
device 932.
[0114] FIG. 10 illustrates using chemically targeted flow control
devices in a multi-lateral application with an intelligent
motherbore completion, according to some embodiments. The
motherbore 1010 has an intelligent completion that includes packers
1040, 1042 and 1044 which hydraulically isolate inflow from
laterals 1020, 1022 and 1024. The flow from each lateral is
controlled using inflow control valves 1050, 1052 and 1054.
Alternatively, sliding sleeves can be used instead of the valves.
The intelligent completion in motherbore 1002 allows for control
and monitoring of individual lateral contributions. Each lateral
1020, 1022 and 1024 can be completed with casing, or openhole, as
shown, as a perforated cased lateral, or as a combination of the
two. Each lateral includes a number of packers that are used to
hydraulically isolate production zones within the subterranean
formation. Each isolated zone preferably includes a flow control
device having both a chemical tracer and chemically triggered
control of the flow, using one or more of the techniques described
herein. For example, in lateral 1020, packers 1012 and 1014 are
used to isolate a zone 1016 of the formation for production into
tubing 1004. The flow of fluid from the formation zone 1016 into
the tubing 1004 is controlled using a flow control device 1018
which preferably includes a chemical tracer sensitive to unwanted
fluid, and a chemically activated shut-off means such as described
herein. The triggering chemical can be delivered using a control
line 1030 as shown, or it can be delivered through the production
tubing 1004 as described herein. Some or all of the flow control
devices can also be equipped with sand screens such as shown with
flow control device 1032.
[0115] FIG. 11 illustrates using chemically targeted flow control
devices in a multi-lateral application with a horizontal
motherbore, according to some embodiments. The motherbore 1110 has
an intelligent completion that includes packers 1140, 1142 and 1144
which hydraulically isolate inflow from laterals 1120, 1122 and
1124. The flow from each lateral is controlled using inflow control
valves 1150, 1152 and 1154. Alternatively, sliding sleeves can be
used instead of the valves. The intelligent completion in
motherbore 1102 allows for control and monitoring of individual
lateral contributions.
[0116] According to some embodiments, the structures, chemistry and
techniques described herein are used for injection of fluids into
the formation, instead of control of fluid flow from the formation.
For example, injection devices can be used for fracturing or other
stimulation procedures, which can be selectively activated by use
of a chemical trigger mechanism. The embodiments of all of the
foregoing figures can be adapted to operate in reverse--to
selectively control injection of fluid into the formation. Specific
examples of injection devices are shown in FIGS. 2A, 2B, 3A and 3B
in which the injection flow is shown in dotted-line arrows. Another
specific example of an injection flow control device is shown in
FIG. 13.
[0117] FIG. 13 illustrates an injection flow control device,
according to some embodiments. Injection flow control device 1300
has a cylindrical body through which injection fluid can flow from
tubing 1302 into a zone 1304 in the subterranean formation. The
injection fluid flows through an orifice plate 1312 that includes a
number of uniformly sized orifices. Flow control device 1300
includes an annular chamber 1310 that is made of acid soluble
material such as carbonate rock is installed into a well section.
According to some embodiments, chamber 1310 contains a chemical or
chemicals that will swell when reacting with a specific injection
fluid, such as shown in and described with respect to FIGS. 6A-B.
According to some other embodiments, the chamber 1310 contains
pre-sized sealing balls (not shown) that can be released to plug
the orifices in plate 1312 of the flow control device 1300, such as
shown in and described with respect to FIGS. 5A-B. According to
some embodiments a control line 1340 is used to direct the
triggering chemical directly to the chamber 1310. According to
other embodiments, the triggering chemical can be bullheaded as
described with respect to FIGS. 4A-E. According to some
embodiments, the release of the sealing balls is done by injecting
an acid that dissolves the chamber. According to other embodiments,
other materials can be used for the construction of the chamber
including plastic, organic and inorganic compounds that can be
dissolved by specific fluids. In FIG. 12, Table 1 gives a number of
alternative options of chemicals that could be deployed for such a
purpose. According to some embodiments, a shrinkable material is
used in chamber 1310 such that the injection flow control device
1300 is normally closed (analogous to chamber 610 shown in FIG.
6b), and the exposure to a triggering chemical causes the material
in chamber 1310 to shrink and open such as shown FIG. 13.
[0118] According to some embodiments a combination of inflow
control devices and injection flow control devices are deployed in
a wellbore and can be selectively triggered using introduced
chemicals according to the teachings provided herein.
[0119] FIGS. 14A-B are quarter cut-away side-views showing some
components of a downhole flow control device having an indicator
chemical released to confirm device actuation, according to some
embodiments. Flow control device 1420 is similar in most respects
to inflow control device 220 as shown in FIGS. 2A-C, and can also
operate in injection mode, according to some embodiments. The
device 1420 can be actuated in the same fashion as described with
respect to device 220 in FIGS. 2A-C, namely, a trigger chemical is
used to dissolve or react with stop device 244 such that the stop
no longer retains the choke sleeve 1426. The choke sleeve 1426 is
urged to the left by coil spring 240 such that it covers the choke
orifices 224a, 224b and 224c. However according to these
embodiments a material containing a further chemical, "indicator
chemical" 1450 is included in the choke sleeve. When the choke
sleeve 1426 is in the closed position, as shown in FIG. 14B, the
chemical 1450 mixes with the wellbore fluids flowing in flowline
202 and can be detected upstream by sampling the production stream.
This chemical 1450 is considered an "indicator" a specific device
has physically actuated downhole, thereby providing assurance to
the operator that particular device has shifted (closed or open
depending on configuration).
[0120] FIGS. 15A-B are quarter cut-away side-views showing some
components of downhole flow control devices having self-triggering
capability, according to some embodiments. Flow control devices
1520 and 1522 are similar in most respects or identical to inflow
control devices 220 and 222 as shown in FIG. 2A, and can also
operate in injection mode, according to some embodiments. Specific
chemical tracer chemicals 1552 and 1554 are positioned as shown on
the outer surface of the device as shown. The tracer chemicals are
designed to be dissolved by or to react with the unwanted produced
fluids such that the chemical is released into the produced fluid
stream and can be detected on the surface thereby indicating the
presence of the unwanted fluid at the particular device. Different
chemical or unique chemical additives can be used to uniquely
identify which device or devices through which the unwanted fluids
are starting to flow into the wellbore. For example, for water
control, the tracer chemical would be one in which water contacts
it for a pre-determined period, degrades and dissolves and can be
detected on the surface (or elsewhere downstream).
[0121] According to some embodiments, the tracer chemical
encapsulates a separate trigger chemical which flows with the
production stream to the control device. In the example shown in
FIGS. 15A-B, tracer chemical 1552 encapsulates trigger chemical
1528, and tracer chemical 1554 encapsulates trigger chemical 1530.
The trigger chemical released is designed to trigger the actuation
device, thereby automating the process of flow control. In the case
of device 1520, trigger chemical 1528 dissolves a stop device in
device 1520 such that the choke sleeve 226 slides to cover the
choke orifices 224a and 224b. Thus an operator on the surface is
notified via the tracer that a particular device is associated with
the production of the unwanted fluid, and the device is
automatically shut off by the encapsulated trigger chemical. Thus,
the capability for automatically actuated downhole devices is
provided without the intervention or pumping of a trigger chemical,
according to some embodiments. This type of device could be
considered an "autonomous" device as is generally understood by the
industry.
[0122] According to some embodiments, the techniques of FIGS. 14A-B
and 15A-B can be combined. For example, the indicator chemical 1450
can be included in the choke sleeves of the automatically triggered
devices 1520 and 1522. Thus an operator on the surface would obtain
confirmation that the automatically triggered device had in-fact
been shut off.
[0123] While the subject disclosure is described through the above
exemplary embodiments, it will be understood by those of ordinary
skill in the art that modification to and variation of the
illustrated embodiments may be made without departing from the
inventive concepts herein disclosed. Moreover, while the
embodiments are described in connection with various illustrative
structures, one skilled in the art will recognize that the system
may be embodied using a variety of specific structures.
Accordingly, the subject disclosure should not be viewed as limited
except by the scope and spirit of the appended claims.
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