Controlled Production and Injection
BACKGROUND
[0001] The present disclosure relates to producing resources from a subterranean zone.
[0002] Often, an injection treatment will be applied to a well prior to putting the well on
production or at some point during production. Some example injection treatments
include acidizing or solvent injection to remove near wellbore damage, steam injection to
mobilize resources in a formation, and water or polymer-laden fluid sweeping to
pressurize and sweep resources in a reservoir to a desired location. There are other types
of injection treatments. Because it is costly and time consuming to run different well
strings into and out of a wellbore, the injection treatments are performed with the
production string when practicable.
SUMMARY
[0003] The present disclosure relates to producing resources from a subterranean zone.
[0004] A well production and injection string is described for use in a wellbore. The
string includes a plurality of spaced apart packers each adapted to seal with a wall of the
wellbore. A plurality of flow control devices are provided in the string, distributed
between pairs of adjacent packers. The flow control devices are adapted to communicate
flow between an interior and an exterior of the string with less restriction to flow from the
interior to the exterior of the string than to flow from the exterior to the interior of the
string.
[0005] A method of accessing a subterranean zone is described. According to the
method, an annulus between a well string and a wellbore is sealed at a plurality of
locations. An injection fluid is injected from the well string into the subterranean zone
between the plurality of sealed locations through a first flow area that provides a first
flow resistance. Production fluid is received from the subterranean zone between the
plurality of locations through a second flow area that provides a second, greater flow
resistance. In certain instances, the first flow area is reduced to provide the second flow
area.
[0006] A well system is described. The well system includes a wellbore extending from
a terranean surface to a subterranean zone. Additional, the system includes a well string
having tubing and a plurality of seals arranged along the tubing. Each of the seals is
adapted to seal with a wall of the wellbore. A plurality of flow control devices are
arranged along the tubing and distributed between pairs of adjacent seals. The flow
control devices are adapted to communicate outflow from an interior to an exterior of the
string through a first flow area and inflow from the exterior of the string to the interior of
the string through a second, smaller flow area. In certain instances, the first flow area is
reduced to provide the second flow area.
[0007] In certain instances, the flow control devices can include a plurality of flow
passages between an interior and an exterior of the string and a subset of the passages
include one-way passages that restrict fluid flow from the exterior to the interior of the
string. In certain instances, the one-way passages have check valves adapted to close the
passage in response to a pressure differential between the interior and exterior of the
string. In certain instances, the flow area to flow from the interior to the exterior of the
string is greater than the flow area to flow from the exterior to the interior of the string.
The packers or seals can be distributed along substantially the entire production/injection
interval of the string. In certain instances, the flow control devices are adapted to provide
substantially uniform flow of fluids between the exterior and the interior of the string
along the entire production/injection interval. In certain instances, the flow control
devices are less restricting to flow between the exterior and interior of the string as the
location of the flow is more toward an end of the string. The string can include a plurality
of particulate control screens configured to filter against passage of particulate larger than
a specified size from the exterior to the interior of the string.
[0008] The details of one or more embodiments of the invention are set forth in the
accompanying drawings and the description below. Other features, objects, and
advantages of the invention will be apparent from the description and drawings, and from
the claims.
DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a schematic cross-sectional view of an example production/injection
string residing in wellbore.
[0010] FIGS. 2A-B are schematic detail cross-sectional views of the example
production/injection string showing an example particulate control screen and an
associated example one-way flow control device. FIG. 2A depicts flow from an interior
of the string to an exterior of the string, and FIG. 2B depicts the flow control device
responding to flow from an exterior of the string.
[0011] FIGS. 3A-C are schematic detail cross-sectional views of the example
production/injection string showing another example one-way flow control device. FIG.
3B depicts flow from an interior of the string to the exterior of the string, and FIG. 3C
depicts the flow control device responding to flow from an exterior of the string.
[0012] Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0013] Referring first to FIG. 1, an example production/injection string 10 is shown
residing in wellbore 12.
[0014] The wellbore 12 extends substantially vertically from a terranean surface 14 into
the earth and deviates to substantially horizontal. Although the wellbore 12 is depicted as
being substantially horizontal, in other instances, the entire wellbore and/or portions
thereof may be vertical or may deviate to be slanted, curved or otherwise non-vertical.
Similarly, although the wellbore 12 is depicted as being a single wellbore, in other
instances, wellbore 12 can be one of a multilateral wellbore configuration having one or
more lateral wellbores extending from a main wellbore. The wellbore 12 provides access
to a target subterranean zone 16, where the subterranean zone can correspond to a
particular geological formation, can be a portion of a geological formation, or can include
two or more geological formations. Casing 18 extends from a wellhead 20 at the surface
14 through a portion of the wellbore 12, typically (but not necessarily) terminating in the
subterranean zone 16. In certain instances, the casing 18 is cemented and/or otherwise
affixed to the wall of the wellbore 12. In certain instances, the casing 18 is unapertured
wall tubing. A portion of the wellbore 12 is depicted as being open hole, without casing
18 and with the surface of the subterranean zone 16 exposed to allow exchange of fluid
between the wellbore 12 and the subterranean zone 16. In other instances, the entire
wellbore 12 can be cased and the casing 18 provided with apertures or perforations to
allow exchange of fluid between the wellbore 12 and the subterranean zone 16.
[0015] The example production/injection string 10 includes one or more lengths of
tubing and other components sized to be received in (i.e., run-in) the wellbore 12 and
operate in injecting fluids into and/or withdrawing (i.e., producing) fluids from the
subterranean zone 16. The tubing can be jointed tubing coupled end to end (threadingly
and/or otherwise) and/or coiled tubing. Although the specific components and their
arrangement in the string can vary from application to application, FIG. 1 depicts an
example production/injection string 10 that facilitates description of the concepts herein.
[0016] In the example of FIG. 1, the production/injection string 10 includes a production
packer 22 positioned in the string 10 to reside proximate the downhole end of the casing
18 when the production/injection string 10 is installed in the wellbore 12. The production
packer 22 is actuated (mechanically, hydraulically and/or otherwise) to seal with the
casing 18 and prevent passage of fluids through the annulus between the string 10 and
casing 18.
[0017] The portion of the production/injection string 10 in the subterranean zone 16,
downhole of the production packer 22, defines a production/injection interval of the
string 10. The production/injection interval is configured to communicate fluids between
an interior of the string 10 and the subterranean zone 16, via the wellbore 12. To this end,
the string 10 of FIG. 1 includes a plurality of spaced apart particulate control screens 24
with associated flow control devices 26. The flow control devices 26 include flow
passages that communicate flow between the interior and exterior of the string 10 and are
coupled to communicate with the particulate control screens 24. The particulate control
screens 24 filter against passage of particulate larger than a specified size into the
passages of flow control devices 26 and the interior of the string 10. For example, the
particulate control screens 24 can filter against sand and gravel displaced from the
subterranean zone 16 or installed in the wellbore 1 as part of a gravel or frac packing
operation.
[0018] The string 10 further includes a plurality of spaced apart packers 28 that each are
actuated (mechanically, hydraulically and/or otherwise) to seal with a wall of the
wellbore 12 and prevent passage of fluids through the annulus between the string 10 and
the wall of the wellbore 12. Adjacent pairs of packers 28 define production/injection subintervals
of the string 10 therebetween, and when actuated to seal with the wall of the
wellbore 12, isolate fluid in the annulus of one sub-interval from other sub-intervals. The
particulate control screens 24 and flow control devices 26 are positioned in the string 10
between pairs of adjacent packers 28. Thus, all fluid in the annulus of a given subinterval
is constrained to flow into the string 10 through the particulate control screens 24
and associated flow control devices 26 within the sub-interval. Conversely, fluid in the
string 10 expelled through the flow control devices 26 and particulate control screens 24
is directed into the subterranean zone 16 between the packers 28 defining the boundaries
of the sub-interval. Although FIG. 1 shows one particulate control screen 24 and its
associated flow control devices 26 per production/injection sub-interval, more than one
could be provided. Also, as described in more detail below, each particulate control
screen 24 can be associated with a single flow control device 26 or multiple flow control
devices 26 (two shown, but more can be provided). In instances of multiple flow control
devices 26 per screen 24, each within a sub-interval may configured alike or differently.
[0019] In certain instances, one or more of the flow control devices 26 in a sub-interval
can be provided with flow passages that have asymmetrical flow properties between
inflow and outflow, e.g., passages that allow outflow and resist or seal against inflow or
vice versa. Such asymmetrical flow control devices 26 can be mixed with symmetrical
flow control devices 26 or other oppositely flowing asymmetrical flow control devices 26
to provide different inflow and outflow (i.e., injection and production) characteristics in
different sub-intervals and along the whole production/injection interval. For example,
the rate of outflow of fluid needed for a given injection treatment may be greater than the
rate of inflow of fluids produced from the subterranean zone 16. Therefore, to account
for this, the arrangement of flow control devices 26 in a string 10 can be configured to
offer less resistance to outflow of fluid from the interior to the exterior of the string 10
than to inflow of fluid from the exterior to the interior. Additionally, the injection fluids
and fluids produced from the subterranean zone 16 may have different properties that
affect how much resistance to flow is needed to achieve a specified flow rate. For
example, the injection fluids and production fluids may have different viscosities, be at
different pressures, and/or have other different properties. Thus, in addition to
accounting for the different amounts of fluid flow, the resistance to inflow or outflow of
the flow control devices 26 can be selected to compensate for the different fluid
properties to achieve a specified amount of fluid flow.
[0020] One manner of providing different resistance to flow is to provide different flow
areas through the flow control devices 26, for example, with greater flow area tending to
provide less resistance to flow and lesser flow area tending to provide more resistance to
flow. Thus, to provide flow control devices with less resistance to outflow than inflow,
these flow control devices 26 can have a greater flow area through the flow control
device 26 for outflow than for inflow. Also, all the flow control devices 26 in a string, or
even in a sub-interval, need not provide the same resistance to inflow and outflow.
Rather, different flow control devices 26 in different or the same production/injection
sub-intervals can have different resistance to inflow, outflow or both. For example, if a
given sub-interval is provided with a flow control device 26 having a one-way fluid
passage, a second flow control device 26 having a two-way flow passage or having a one
way fluid passage oriented to flow oppositely of the first flow control device 26 would
allow the sub-interval to flow both during injection and production yet have a different
flow area (and different flow resistance) depending on the direction of flow. Also, the
flow control devices 26 can include devices 26 that each have both one-way or
asymmetrical and symmetrical fluid passages.
[0021] By selection and arrangement of flow control devices 26, a specified outflow
amount and/or inflow amount profile, i.e., in injection and/or production, can be achieved
over the entire length of the production/injection interval. In certain instances, the
specified flow profile can be substantially uniform radial outflow and inflow over the
entire length of the production/injection interval. For example, a desired flow profile for
30 barrels per minute of radial outflow (i.e., injection) during an acid stimulation
treatment in a well with 30 production/injection intervals could be a uniform outflow of
about 1 barrel per minute per interval, whereas the expected radial inflow (i.e.,
production) during production of the same well could be 15,000 barrels per day, with
uniform inflow of about 0.35 barrel per minute per interval. These flow rates are
mentioned merely as an example, and significant variances in uniformity of actual flows,
e.g., even 50% variance from strict uniformity, still fall within the bounds of this method
as the possible variance of flows without the system and method described here could be
much greater than 50% variance and the system and method would therefore move the
flows substantially toward uniformity without achieving strict uniformity.
[0022] The flow profile can be the same in production as it is in injection or the
production flow profile can be different from the injection flow profile.
[0023] Because of the so-called heel/toe effect (where factional pressure causes an
inflow/outflow gradient along the length of a production/injection interval), areas of
differing permeability or natural or manmade fractures in different parts of the
subterranean zone 16, and other effects, the local inflow/outflow rate of fluid with the
subterranean zone 16 varies along the production/injection interval. The restriction to
flow provided by the flow control devices 26 can be different at different locations along
the string 10 to account for this. For example, flow control devices 26 with a lesser
resistance to inflow (e.g., having a greater flow area) can be provided in areas of low
permeability, and flow control devices 26 with a greater resistance to inflow (e.g., having
a lesser flow area) can be provided in areas of high permeability. Flow control devices
26 with a lesser resistance to outflow can be provided in areas of low permeability to
facilitate greater stimulation of those areas during injection, while areas already having
high permeability would have flow control devices 26 with a higher resistance to outflow.
To account for the heel/toe effect, the flow control devices 26 can be provided with a
generally decreasing resistance to flow from the heel of the production/injection interval
(near the production packer 22) towards the toe of the production/injection interval (and
farthest from the production packer 22). Other flow profiles along the
production/injection interval can be provided, for example, those that are not necessarily
substantially uniform or that may be substantially uniform in injection but not in
production or vice versa. Different flow profiles along the production/injection interval
can be provided by providing other arrangements of flow control devices 26, including
different mixes of one-way flow, asymmetric flow and symmetric flow passages,
different numbers of flow control devices (none, one, two, three or more) in each
production/injection sub-interval, and/or flow control devices with different flow areas.
[0024] The same string 10 can be used in one or both of production of fluids from the
subterranean zone 16 and injection of fluids into the subterranean zone 16. In one
example, the string 10 is used to inject stimulating fluids (e.g., acid in an acidizing
treatment, xylene in a solvent treatment, steam in a heated fluid injection treatment,
and/or other types of stimulating fluid) into the subterranean zone 16 substantially
uniformly, or in some other flow profile, along the length of the production/injection
interval. Thereafter, the string 10 is used to produce fluids (e.g., hydrocarbons and/or
other fluids) from the subterranean zone 16 substantially uniformly, or in some other flow
profile, along the length of the production/injection interval. In another example, the
string 10 is used for injection of sweeping fluids (e.g., water, brine and/or other fluids
such as polymer- laden fluids) into the subterranean zone 16 substantially uniformly, or in
some other flow profile, along the length of the production/injection interval for the
purpose of maintaining pressure in the subterranean zone 16 and sweeping the zone's
fluids to a specified location in the subterranean zone 16. The well may be shut-in while
the sweeping fluids reside in the subterranean zone 16. In certain instances, the greater
resistance or sealing against inflow into the string 10 can limit cross-flow of fluids from
one sub-interval, through the string 10 and out to another sub-interval. Thereafter, the
string 10 is used to produce fluids (e.g., hydrocarbons and/or other fluids) from the
subterranean zone 16 substantially uniformly, or in some other flow profile, along the
length of the production/injection interval.
[0025] Referring now to FIGS. 2A-B, schematic detail cross-sectional views of the
example production/injection string are provided and show an example particulate control
screen 40 suitable for use as screen 24 and an associated one-way example flow control
device 42 suitable for use as flow control device 26. FIG. 2A depicts outflow from an
interior of the string to an exterior of the string (shown by arrows) and FIG. 2B depicts
the device's response to inflow from an exterior of the string to an interior of the string
(also shown by arrows). In this instance, the particulate control screen 40 is depicted as a
wire wrapped screen, having a wire 44 helically wrapped around a base pipe 46. The
space between adjacent wraps of the wire 44 is closely controlled to be smaller than the
specified size of particulate filtered by the screen 40. The base pipe 46 is configured to
couple (threadingly and/or otherwise) with the remainder of the string. Although
depicted as a wire wrapped screen, other configurations of screens, including screens
having one or more layers of wire wrap, mesh and/or other filtration structures, could be
used.
[0026] The flow control device 42 has an exterior housing 48 with one end sealed to the
base pipe 46 and the other end coupled to the end of the screen 40, such that fluid is
communicated from the interior of the housing 48 (between the housing 48 and the base
pipe 46) and the interior of the screen 40 (between the wire 44 and the base pipe 46). A
flexible sleeve 50 is fit tightly around the base pipe 46 in the interior of the housing 48.
In certain instances, the flexible sleeve 50 is polymer, such as butyl rubber, VITON
fluoroelastomer (a registered trademark of DuPont Performance Polymers, LLC), and/or
other polymer. The end of the sleeve 50 opposite the screen 40 is sealed to the base pipe
46, and the end of the sleeve 50 towards the screen 40 is free. A plurality of
circumferentially spaced apertures 52 are provided in the base pipe 46, intermediate the
ends of the sleeve 50, that communicate flow between the interior and exterior of the base
pipe 46.
[0027] As shown in FIG. 2A, when pressure in the interior of the base pipe 46 is higher
than the pressure exterior of the base pipe 46, fluid flows from the interior of the base
pipe 46, through the apertures 52. The fluid tends to push the free end of the flexible
sleeve 50 away from the exterior of the base pipe 46 and passes between the sleeve 50
and the base pipe 46, into the screen 40, and out into the subterranean zone 16. As seen
in FIG. 2B, when pressure in the interior of the base pipe 46 is lower than the pressure
exterior of the base pipe 46, the pressure differential tends to hold the flexible sleeve 50
into sealing engagement with the exterior of the base pipe 46 thus restricting, and in
certain instances sealing against, flow of fluid from the exterior of the base pipe 46 to the
interior of the base pipe 46. No intervention into the wellbore or string is required to
actuate the flow control device 42 between restricting or sealing against inflow and
allowing outflow. Rather, the flow control device is response to pressure and direction of
flow.
[0028] Although described as a one-way flow control device, the flow control device 42
can alternatively be configured as a two-way flow control device having a greater
resistance to flow from the exterior to the interior of the base pipe 46 than from the
interior to the exterior of the base pipe 46. For example, additional apertures 52 not
covered by the sleeve 50, and thus not restricted to one-way flow, can be included in the
base pipe 46. These additional apertures 52 would then allow inflow into the base pipe
46 and thus allow two-way flow. The total flow area through the wall of the base pipe 46
would be greater for outflow from the interior than inflow from the exterior, because
during outflow from the interior of the base pipe 46 all apertures 52 (those beneath sleeve
50 and those not covered by the sleeve 50) would be available for flow. During inflow
from the exterior of the base pipe 46 the total flow area through the wall of the base pipe
46 would be reduced, because the apertures 52 beneath the sleeve would be restricted or
sealed by the sleeve 50.
[0029] FIGS. 3A-C are schematic detail cross-sectional views of the example
production/injection string showing another example one-way flow control device 54
suitable for use as flow control device 26. FIG. 3B depicts outflow from an interior of
the string to the exterior of the string (shown by arrows) and FIG. 3C depicts the
response of the flow control device 54 to inflow from an exterior of the string to an
interior of the string (also shown by arrows).
[0030] The flow control device 54 has an exterior housing 56 with one end sealed to the
base pipe 46 and the other end coupled to the end of the screen 40 such that fluid is
communicated from the interior of the housing 48 (between the housing 48 and the base
pipe 46) and the interior of the screen 40 (between the wire 44 and the base pipe 46). A
plurality of circumferentially spaced check valves 58 are provided in the wall of the base
pipe 46 to communicate flow therethrough. The check valves 58 are configured to allow
outflow from the interior of the base pipe 46 (and thus string) to the exterior of the base
pipe 46, and close to restrict or seal against inflow from the exterior to the interior of the
base pipe 46.
[0031] As best seen in FIGS. 3B and 3C, the check valve 58 includes a cylindrical
plunger 60 with a frustoconical tip that is carried in cylindrical cavity of a valve housing
62. The valve housing 62 has a bottom port 66 open to the interior of the base pipe 46
and an upper port 68 (shown in the side of the valve housing 62) open to the interior of
the flow control device housing 56. The plunger 60 is sealed to the interior diameter of
valve housing 62 with a seal 70 (e.g., o-ring and/or other type of seal). The plunger is
biased into the bottom port 66 by a spring 64 acting between the plunger 60 and top 72 of
the valve housing 62. The top 72 is affixed (threadingly and/or otherwise) to the
remainder of the valve housing 62. As shown in FIG. 3B, when pressure is greater in the
interior than the exterior of the base pipe 46, flow lifts the plunger 60 and allows outflow
of fluid from the interior to the exterior of the base pipe 46. When the plunger 60 is
seated in the bottom port 66, the seal 70 is beneath the upper port 68. Thus, when
pressure is greater about the exterior than in the interior of the base pipe 46, pressure
holds the plunger 60 down. The check valve 58 is thus held closed, and the seal 70 of the
plunger 60 seals against inflow from the exterior to the interior of the base pipe 46. No
intervention into the wellbore or string is required to actuate the flow control device 54.
Rather, the flow control device 54 responds to pressure and direction of flow.
[0032] Although described as a one-way flow control device, the flow control device 54
can alternatively be configured as a two-way flow control device having a greater
resistance to inflow from the exterior to the interior of the base pipe 46 than outflow from
interior to exterior of the base pipe. For example, in addition to the check valves 58,
additional apertures can be provided in the base pipe 46. These additional apertures
would not be governed by the flow of the check valves 58, and thus would allow twoway
flow through the base pipe 46. The total flow area through the wall of the base pipe
46 would then be greater for outflow from interior than inflow from the exterior of the
base pipe 46, because both the check valves 58 and the additional apertures would be
available for outflow. During inflow from the exterior of the base pipe 46 the total flow
area through the wall of the base pipe 46 would be reduced, because the check valves 58
would seal against inflow leaving only the additional apertures available for inflow.
[0033] Notably, the flow control devices 42 or 54 can be provided with a different
number and/or sizes of apertures 52 or check valves 58 to provide increased or decreased
resistance to fluid flow. For example, more apertures 52 or check valves 58 of a given
size can be provided to increase the flow area through the wall of the base pipe 46 and
provide less resistance to flow. Fewer apertures 52 or check valves 58 and given size can
be provided to decrease the flow area and provide more resistance to flow. Similarly,
apertures 52 or check valves 58 of a greater flow area can be provided to yield less
resistance to flow through the wall of the base pipe 46. Apertures 52 or check valves 58
having a smaller flow area can be provided to provide more resistance to flow through
the wall of the base pipe 46. Different configurations of flow control devices, such as
flow control devices 42, 54 (in one-way and/or two-way configurations) and/or other
configurations of flow control devices (one-way and/or two-way), can be provided to
tailor the flow profile along the string.
[0034] Other types and configurations of flow control devices can be used in lieu of or in
combination with those described above. For example, a fluid diode based valve, such as
that described in U.S. Patent Application No. 12/700,685, entitled Method and Apparatus
for Autonomous Downhole Fluid Selection with Pathway Dependent Resistance System,
filed February 4, 2010, or that described in U.S. Patent Application No. 12/966,772,
entitled Downhole Fluid Flow Control System and Method Having Direction Dependent
Flow Resistance, filed December 13, 2010, is a fluidic device that relies on fluid
properties (rather than opening and closing a port with a mechanical device) to produce a
different resistance to fluid flowing in one direction through the fluid diode than another.
By using the fluid diode based valve in a flow control device, it can provide a flow
control device with an asymmetrical inflow/outflow. The above-mentioned application
describes a number of different configurations of fluid diode based valves, and some are
responsive to change resistance to flow based on at least one of the flow rate, viscosity or
density of the fluid in addition to flow direction. Thus, for example, by using one of
these configurations the flow control devices can become more restrictive of fluid flow as
the flow rate increases and less restrictive as the flow rate decreases or vice versa. Also,
for example, the flow control devices can become more restrictive of fluid flow as the
viscosity fluid increases and less restrictive of viscosity of the fluid decreases or vice
versa. Also, for example, the flow control devices can become more restrictive of fluid
flow as the fluid density increases and less restrictive as the fluid density decreases or
vice versa. In certain instances, thus the flow control devices can automatically be more
restrictive to water than oil or vice versa, more restrictive to gas than oil or vice versa,
and/or more restrictive to production flow than to injection flow or vice versa.
[0035] A number of examples have been described. Nevertheless, it will be understood
that various modifications may be made. Accordingly, other examples are within the
scope of the following claims.
WHATIS CLAIMED IS:
1. A well production and injection string for use in a wellbore, the string comprising:
a plurality of spaced apart packers each adapted to seal with a wall of the
wellbore; and
a plurality of flow control devices distributed between pairs of adjacent
packers, the plurality of flow control devices adapted to communicate flow between
an interior and an exterior of the string with less restriction to flow from the interior
to the exterior of the string than to flow from the exterior to the interior of the string.
2. The well production and injection string of claim 1, wherein the flow control devices
comprise a plurality of flow passages between an interior and an exterior of the string
and a subset of the passages comprise one-way passages that restrict fluid flow from
the exterior to the interior of the string.
3. The well production and injection string of claim 2, wherein the one-way passages
comprise check valves adapted to close the passage in response to a pressure
differential between the interior and exterior of the string.
4. The well production and injection string of claim 1, wherein the flow area to flow
from the interior to the exterior of the string is greater than the flow area to flow from
the exterior to the interior of the string.
5. The well production and injection string of claim 1, wherein the wellbore extends
from a terranean surface into a target subterranean zone and the portion of the string
in the target subterranean zone defines a production/injection interval, and
wherein the packers are distributed along substantially the entire
production/injection interval.
6. The well production and injection string of claim 5, wherein the flow control devices
are adapted to provide substantially uniform flow of fluids between the exterior and
the interior of the string along the entire production/injection interval.
7. The well production and injection string of claim 5, wherein the flow control devices
are less restricting to flow between the exterior and interior of the string toward an
end of the string.
8. The well production and injection string of claim 1, further comprising a plurality of
particulate control screens configured to filter against passage of particulate larger
than a specified size from the exterior to the interior of the string.
9. A method of accessing a subterranean zone, comprising:
sealing an annulus between a well string and a wellbore at a plurality of locations;
injecting an injection fluid from the well string into the subterranean zone
between the plurality of locations through a first flow area that provides a first flow
resistance; and
receiving production fluid from the subterranean zone between the plurality of
locations through a second flow area that provides a second, different flow resistance.
10. The method of claim 9, further comprising reducing the first flow area to yield the
second flow area.
11. The method of claim 10, wherein reducing the first flow area comprises sealing a
plurality of flow passages of the first area against flow.
12. The method of claim 9, wherein the plurality of locations span between a heel and toe
of a wellbore and the first flow resistance is a flow resistance profile that produces a
substantially uniform flow of fluid into the subterranean zone between the heel and
the toe of the wellbore.
13. The method of claim 12, wherein the first flow resistance profile is greater at the heel
of the wellbore than the toe of the wellbore.
14. The method of claim 12, wherein the first flow resistance profile is greater in
locations of the subterranean zone having a higher permeability.
15. The method of claim 9, wherein the first flow area is greater than the second flow
area.
16. The method of claim 9, wherein injecting an injection fluid comprises injecting at
least one of acid, hydrocarbon solvent or steam for stimulating production from the
subterranean zone.
17. A well system, comprising:
a wellbore extending from a terranean surface to a subterranean zone;
a well string comprising:
tubing;
a plurality of seals arranged along the tubing and each adapted to seal with
a wall of the wellbore; and
a plurality of flow control devices arranged along the tubing and
distributed between pairs of adjacent seals, the plurality of flow control devices
adapted to communicate outflow from an interior to an exterior of the string through a
first flow area and inflow from the exterior of the string to the interior of the string
through a second, smaller flow area.
18. The well system of claim 17, wherein the first flow area comprises a plurality of flow
passages between the interior and exterior of the string and the second flow area
comprises a subset of the plurality of flow passages.
19. The well system of claim 18, wherein flow passages comprise check valves oriented
to seal against inflow into the string.
20. The well system of claim 17, wherein the first flow area is arranged to provide
substantially uniform flow into the subterranean zone.