Note: Descriptions are shown in the official language in which they were submitted.
DEPLOYABLE BAFFLE
BACKGROUND
Hydrocarbon-producing wells commonly consist of a wellbore lined with a
casing.
The casing is typically cemented in place by pumping cement into an annulus
between the
wellbore and casing. Once cemented in place, a perforating gun is lowered to
depth within
the casing and fired to create one or more perforations extending through the
casing and
cement and into the surrounding formation. The perforations generally permit
communication
of fluid between the internal volume of the casing and the surrounding
formation.
Once perforated, wells are often stimulated using various stimulation
treatments. In
hydraulic fracturing treatments, a viscous fracturing fluid is pumped into a
perforated
production zone at sufficiently high pressure to fracture and propagate
fractures through the
production zone. The fractures provide enhanced pathways for fluid to move
from the
formation into the casing, thereby improving well production.
Acidizing, or similar treatments, may also be performed instead of or in
addition to
fracturing treatments. Such treatments involve the introduction of an acid or
similar fluid into
the formation. Doing so dissolves debris introduced into the formation during
the perforating
and fracturing processes and/or improves permeability of the formation by
enlarging existing
fluid pathways within the formation.
A single well may include multiple production zones, with each production zone
requiring its own perforation and stimulation. Production zones are typically
perforated and
stimulated beginning with the farthest downhole production zone and proceeding
uphole.
Stimulation of a production zone may require isolation of the production zone
from other
previously-treated production zones. For example, in fracturing treatments,
isolation enables
more efficient build-up of pressure within the production zone to be fractured
by preventing
fluid losses to the formation via a previously-fractured production zone and
may also protect
the previously-fractured production zone from additional, unwanted fracturing.
Given the prevalence of fracturing operations, there is a consistent drive
among
operators to lower costs and improve installation efficiencies associated with
completion and
fracturing operations.
SUMMARY
In accordance with a general aspect, there is provided a method of treating a
subterranean formation having a wellbore formed within the subterranean
formation, the
method comprising inserting a baffle apparatus into a casing disposed in the
well bore, the
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baffle apparatus comprising a one-piece sleeve having an expandable section;
and expanding
the expandable section by activating a setting tool so that an outer surface
of the expandable
scction contacts at least a portion of an inner wall of the casing.
In accordance with another aspect, there is provided a downhole completion
system,
comprising a casing disposed within a wellbore; a baffle apparatus comprising
a one-piece
sleeve having an expandable section and an insert disposed within the one-
piece sleeve,
wherein the baffle apparatus is disposable on an inner surface of the casing
by expanding the
expandable section such that an outer surface of the expandable section
contacts an inner
surface of the casing.
In accordance with a further aspect there is provided a baffle apparatus for
use in
subterranean fracturing operations, comprising: a one-piece sleeve having an
expandable
section; and an insert disposed within the sleeve, wherein the expandable
section is
expandable within a casing by activating a setting tool within the one-piece
sleeve.
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BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present embodiments and advantages
thereof may
be acquired by referring to the following description taken in conjunction
with the accompanying
drawings, in which like reference numbers indicate like features.
FIG. 1 is a cross-sectional view of a deployable baffle in accordance with one
embodiment.
FIGS. 2A and 2B are cross-sectional views of a deployable baffle in accordance
with one
embodiment depicting the deployable baffle in an undeployed and deployed
state, repectively.
FIG. 3A-3B are cross-sectional views of an embodiment of a setting tool in an
undeployed and deployed state, respectively.
FIGS. 4A-4F are cross-sectional views of a subterranean formation having a
wellbore
therein and depict an example completion operation including perforation and
fracturing of two
production zones.
While embodiments of this disclosure have been depicted and described and are
defined
by reference to exemplary embodiments of the disclosure, such references do
not imply a
limitation on the disclosure, and no such limitation is to be inferred. The
subject matter disclosed
is capable of considerable modification, alteration, and equivalents in form
and function, as will
occur to those skilled in the pertinent art and having the benefit of this
disclosure. The depicted
and described embodiments of this disclosure are examples only, and not
exhaustive of the scope
of the disclosure.
DETAILED DESCRIPTION
The present disclosure relates generally to fracturing operations and
specifically to a
deployable baffle for isolating production zones to be fractured.
Illustrative embodiments of the present invention are described in detail
herein. In the
interest of clarity, not all features of an actual implementation may be
described in this
specification. It will of course be appreciated that in the development of any
such actual
embodiment, numerous implementation-specific decisions must be made to achieve
the specific
implementation goals, which will vary from one implementation to another.
Moreover, it will be
appreciated that such a development effort might be complex and time
consuming, but would
nevertheless be a routine undertaking for those of ordinary skill in the art
having the benefit of
the present disclosure.
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To facilitate a better understanding of this disclosure, the following
examples of certain
embodiments are given. In no way should the following examples be read to
limit, or define, the
scope of the claims.
FIG. 1 depicts a deployable baffle 100 in an undeployed state. The deployable
baffle 100
includes an outer sleeve 102. The outer sleeve 102 includes an expandable
section 104. As will
be discussed in more detail, the deployable baffle 100 is installed in a
section of casing by
expanding the expandable section 104 using a setting tool. When expanded, the
expandable
section 104 engages an inner surface of the section of casing, fixing the
deployable baffle 100
within the section of casing.
In any embodiment, fixation of the deployable baffle 100 within the section of
casing
may be facilitated by an elastomeric liner 106 around at least a portion of
the outside surface of
the expandable section 104. When the expandable section 104 is expanded, the
elastomeric liner
106 seals against the inner surface of the section of casing in which the
deployable baffle 100 is
installed. Alternatively or in addition to the elastomeric liner 106, the
deployable baffle 100 may
include one or more teeth 108. Similar to the elastomeric liner 106, the teeth
108 engage the
inner surface of the section of casing when the expandable section 104 is
expanded, engaging the
inner surface of the casing and anchoring the deployable baffle 100 therein.
The deployable baffle 100 also includes a baffle insert 112. The baffle insert
112 catches
an untethered object inserted into the well, the untethered object being
shaped to seal against a
sealing face 114 of the baffle insert 112. As depicted in FIG. 1, the baffle
insert 112 is inserted
and retained within the outer sleeve 102. Retention of the baffle insert 112
within the outer
sleeve 102 may be accomplished in various ways. For example, the baffle insert
112 may have a
set of outer threads designed to mate with a corresponding set of threads
lining the inner surface
of the outer sleeve 102. The baffle insert 112 may also be installed within
the outer sleeve 102
using other methods such as adhesives, shrink-fitting, brazing or welding, or
by installing a
retaining cap on the end of the outer sleeve 102.
FIG. 2A and 2B depict a deployable baffle 200 positioned within a casing 220
in an
undeployed and a deployed state, respectively. The deployable baffle 200
includes an outer
sleeve 202 and a baffle insert 212. As shown in FIG. 2A, when in the
undeployed state, clearance
exists between an outer surface of an expandable section 204 of the outer
sleeve 202 and an inner
surface 222 of the casing 220. This clearance permits movement of the
deployable baffle 200
within the casing 220 such that the deployable baffle 200 can be accurately
positioned within the
casing 220 before deployment.
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In contrast, in FIG. 2B, the deployable baffle 200 is depicted in the deployed
state with
the expandable section 204 expanded. In the embodiment depicted in FIG. 2B,
expansion of the
expandable section 204 within the casing 220 compresses an elastomeric liner
206 between the
outer surface 210 of the deployable baffle 200 and the inner surface 222 of
the casing 220.
Additionally, expansion of the expandable section 204 causes a set of teeth
208 to engage the
inner surface 222 of the casing 220, further anchoring the deployable baffle
200 in place.
During completion operations, the deployable baffle described above may be
conveyed
into and deployed within the casing by a setting tool. In general, the
deployable baffle is retained
on the setting tool as the setting tool is conveyed into the casing. The
setting tool may be
conveyed into the casing by wireline, e-line, coiled tubing, or any other
suitable method for
conveying equipment downhole. Once in position, the setting tool is activated
to expand the
deployable baffle such that the deployable baffle engages the inner surface of
the casing. The
deployable baffle is then released from the setting tool and the setting tool
is withdrawn from the
easing.
To convey the deployable baffle into the casing, the setting tool includes a
mechanism for
selectively retaining the deployable baffle. Specifically, the mechanism
retains the deployable
baffle on the setting tool as the setting tool is conveyed downhole and
positioned to deploy the
deployable baffle. Once the deployable baffle is deployed, however, the
mechanism permits
release of the deployable baffle such that the setting tool can be retracted.
Various mechanisms may be used to selectively retain the deployable baffle on
the
setting tool. For example, in one embodiment, the deployable baffle may be
retained on the
setting tool by a threaded connection. In such an embodiment, the deployable
baffle would be
released from the setting tool by rotating the setting tool to disengage the
threads after the
deployable baffle is set within the casing. In another embodiment, the
deployable baffle may be
retained on the setting tool by one or more shear pins. In such an embodiment,
the deployable
baffle may be disengaged from the setting tool by shearing the pins by pulling
up on the setting
tool once the deployable baffle is set within the casing. In yet another
embodiment, the setting
tool may include one or more retractable keys. In an extended position, the
keys may engage the
deployable baffle, thereby retaining the deployable baffle on the setting
tool. Once the
deployable baffle is deployed, however, the retractable keys may be retracted
by electrical,
hydraulic, or mechanical means to release the deployable baffle. A hook-based
mechanism, as
depicted in FIGS. 3A and 3B, is discussed in further detail below.
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Once the setting tool and retained deployable baffle have been properly
positioned within
the casing, the setting tool is activated. Activation of the setting tool
causes the setting tool to
expand the deployable baffle such that the deployable baffle engages the
casing.
Generally, activation of the setting tool causes the setting tool to apply
force to the inner
wall of the deployable baffle, thereby expanding an expandable section of the
deployable baffle.
Applying this force can be accomplished in various ways. For example in
certain embodiments,
the setting tool may include an expandable bladder positioned within the
deployable baffle. In
such embodiments, the setting tool is activated by supply a pressurized fluid
to the setting tool to
expand the bladder. As the bladder expands, it contacts the inner surface of
the deployable baffle
and exerts pressure on the inner surface. As pressure within the bladder
rises, the deployable
baffle is expanded to engage the casing.
FIGS. 3A and 3B depict another example of a setting tool 350 that expands a
deployable
baffle 300 using an expansion cone 352. FIGS. 3A and 3B depict the setting
tool 350 in the
unactivated and activated states, respectively. The deployable baffle 300 is
selectively retained
by a set of hooks 362A, 362B that engage a lip 364 disposed on the inner
surface of the
deployable baffle 300.
The setting tool 350 is activated by supplying a pressurized fluid via a fluid
inlet 354 into
a chamber 358. As depicted in FIG. 3B, as pressure increases within the
chamber 358, a sliding
sleeve 360 having the expansion cone 352 disposed on one end is moved such
that the expansion
cone 352 is forced into the deployable baffle 300. As the expansion cone 352
is forced into the
deployable baffle 300, the deployable baffle 300 expands. As the expansion
cone 352 extends
further into the deployable baffle 300, it contacts the hooks 362A, 362B and
causes them to
disengage the lip 364, permitting withdrawal of the setting tool 350.
For setting tools that are activated by pressurized fluid, such as the setting
tool of FIGS.
3A and 3B, pressurized fluid may be supplied in various ways. In embodiments
in which the
setting tool is conveyed using coiled tubing or a similar tubular, fluid may
be pumped from a
source on the surface, through the tubular, and into the setting tool from the
surface.
Alternatively, an explosive charge disposed in the setting tool or another
connected downhole
tool may be detonated to produce the necessary pressure.
To provide further understanding and appreciation of the deployable baffle and
its use, a
description of an example fracturing operation follows. This example is for
illustrative purposes
only and should not be interpreted as limiting the invention to such
operations.
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FIG. 4A depicts a cross-section of a subterranean formation 400 having a
wellbore
410 formed therein. Disposed and cemented in the wellbore 410 is a casing 420.
As depicted,
the subterranean formation 400 includes multiple layers. For purposes of this
example, two of
the layers of the formation are permeable and form a first production zone
405A and a second
production zone 405B. In this example, each of production zones 405A and 405B
are to be
perforated and fractured in preparation for production from the wellbore 410.
Although the
wellbore 410 is depicted as being substantially vertical in FIG. 4A,
embodiments disclosed
herein may also be applied in deviated wellbores.
FIG. 4B depicts isolation of the first production zone 405A. A tool string
including a
setting tool 450, a first deployable baffle 460A, and a perforating gun 470 is
lowered into the
casing 420. The first deployable baffle 460 is disposed on the downhole end of
the setting
tool 450. For deployment of the first deployable baffle 460, the tool string
is positioned such
that the first deployable baffle 460 is positioned below the first production
zone 405A. In any
embodiment, positioning of the tool string within a wellbore may be
accomplished by
measurement-while-drilling (MWD), logging-while-drilling (LWD), or similar
equipment.
Once properly positioned, the setting tool 450 is activated, expanding the
first deployable
baffle 460, setting the first deployable baffle 460 within the casing 420.
As depicted in FIG. 4C, once the first deployable baffle 460A is deployed and
set
within the casing 420, the first deployable baffle 460A is disengaged from the
setting tool
450 and the tool string is repositioned within the wellbore 410 such that the
perforating gun
470 is aligned with the first production zone 405A. The perforating gun 470 is
then fired,
creating a first set of perforations 480A that extend through the casing 420
and into a portion
of the subterranean formation corresponding to the first production zone 405A.
After
perforation, the tool string is withdrawn from the wellbore in preparation for
stimulation,
which in this example involves a hydraulic fracturing treatment.
As depicted in FIG. 4D, once the first deployable baffle 460A is installed in
the
casing 420 and the casing 420 and the first production zone 405A are
perforated, a first ball
490A or similar untethered object may be inserted into the wellbore 410 such
that the first
ball 490A seals against a baffle insert 465A of the first deployable baffle
460A. The seal
between the baffle insert 465A and the first ball 490A isolate sections of the
wellbore 410
downhole form the baffle insert 465A from those uphole of the baffle insert
465A. In cases
where a deployable baffle is deployed in a downhole end of a casing string,
the seal would be
between the wellbore and uphole sections of the wellbore 410. The untethered
object may be
conveyed down the wellbore
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410 using various methods. For example, the untethered object may be shot,
pumped, or
dropped into the wellbore 410. Once the first ball 490A is seated, fracturing
fluid is pumped
into the wellbore 410 at high pressure and enters the subterranean formation
through the first
set of perforations 480A, fracturing the first production zone 405A. FIG. 4D
depicts the
subterranean formation following such a fracturing operation.
In addition to or instead of fracturing operations, other well treatments may
be
administered to the first production zone 405A after the first production zone
405A has been
isolated. For example, an acidizing operation may be conducted following
fracturing to
dissolve and break down debris created by perforation and fracturing, thereby
further
enhancing flow paths between the subterranean formation and casing.
The steps just described with respect to the first production zone 405A may be
repeated for each production zone of a given wellbore. For example, in FIG 4E,
the second
production zone 405B is depicted as being both perforated and fractured.
Completing the
second production zone as depicted in FIG. 4E would generally involve running
a second
deployable baffle 460B on a setting tool into the wellbore and deploying the
second
deployable baffle 460B below the second production zone 405B. The second
production zone
405B could then be perforated and a second untethered object, here a second
ball 490B, may
be inserted into the wellbore to seal against a baffle insert 465B of the
second deployable
baffle 460B, thereby isolating the first production zone 405A from the second
production
zone 405B. A fracturing fluid could then be pumped into the wellbore 410 to
cause fracturing
of the second production zone 40513.
After perforation and fracturing of all production zones is complete, the
untethered
objects may be removed from the wellbore. Removal of the untethered objects
may be
accomplished in various ways. For example, fluid may be pumped from the
wellbore, thereby
reversing pressure within the wellbore, unseating the untethered objects, and
bringing them to
the surface. A milling bit may also be run into the wellbore to mill out the
untethered objects.
Alternatively, the untethered objects may be formed of a dissolvable material.
For
example, the untethered objects may be composed of a material that rapidly
degrades when
exposed to particular chemicals. Such chemicals may he pumped into the
wellbore following
fracturing to dissolve the untethered objects and open a flow path between the
production
zones and the surface.
Because the deployable baffle is no longer necessary following stimulation
treatments, any or all of the components of the deployable baffle may also be
removed from
the wellbore. For example, the inner baffle, which may restrict flow between
the production
zones and the
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surface, may be milled out or dissolved. In some embodiments, the entire
deployable baffle may
be made of a dissolvable material, thereby enabling removal of the entire
deployable baffle
following fracturing.
FIG. 4F depicts an arrangement of the wellbore 410 following completion. As
previously
discussed, following stimulation treatments, the untethered object and any or
all of the
deployable baffle may be made of a material that permits dissolution of the
untethered object or
deployable baffle by circulating abrasive, corrosive, or chemically reactive
fluids within the
wellbore. FIG. 4F depicts the wellbore following such a treatment that
dissolved the first and
second ball and the baffle inserts of both the first and the second deployable
baffles.
Although numerous characteristics and advantages of embodiments of the present
invention have been set forth in the foregoing description and accompanying
figures, this
description is illustrative only. Changes to details regarding structure and
arrangement that are
not specifically included in this description may nevertheless be within the
full extent indicated
by the claims.
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