U.S. patent application number 14/921470 was filed with the patent office on 2016-06-30 for expandable plug seat.
The applicant listed for this patent is HydraWell Inc.. Invention is credited to Rodney D. Bennett, Martin P. Coronado, Luis A. Garcia, Mark E. Plante.
Application Number | 20160186511 14/921470 |
Document ID | / |
Family ID | 54365466 |
Filed Date | 2016-06-30 |
United States Patent
Application |
20160186511 |
Kind Code |
A1 |
Coronado; Martin P. ; et
al. |
June 30, 2016 |
Expandable Plug Seat
Abstract
Disclosed embodiments relate to methods and devices for setting
a plug seat within a downhole well, for example in fracing
operations. In an embodiment, the expandable plug seat may include
an expandable slip ring and one or more wedge rings. To set the
expandable plug seat in place within the casing of the wellbore,
longitudinal force would typically be applied to the one or more
wedge rings, thereby deforming the expandable slip ring and driving
it radially outward and into contact with the casing in the
wellbore. In some embodiments, the expandable plug seat may be used
with a dissolvable ball, which can be pumped to seat onto the plug
seat device for sealing of the wellbore. Once the downstream
section of the well has been isolated in this manner, hydraulic
fracturing operations can commence. Eventually, the ball may
dissolve, allowing access to the wellbore without the need to drill
the plug.
Inventors: |
Coronado; Martin P.;
(Cypress, TX) ; Garcia; Luis A.; (Kingwood,
TX) ; Plante; Mark E.; (Tomball, TX) ;
Bennett; Rodney D.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HydraWell Inc. |
Houston |
TX |
US |
|
|
Family ID: |
54365466 |
Appl. No.: |
14/921470 |
Filed: |
October 23, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62067594 |
Oct 23, 2014 |
|
|
|
Current U.S.
Class: |
166/381 ;
166/209 |
Current CPC
Class: |
E21B 33/129 20130101;
E21B 23/01 20130101; E21B 33/128 20130101; E21B 43/26 20130101 |
International
Class: |
E21B 23/01 20060101
E21B023/01 |
Claims
1. An expandable plug seat device operable to be set within casing
for a wellbore, comprising: an expandable slip ring, wherein the
expandable slip ring is configured to expand by deforming radially
outward; and one or more wedge rings configured to slide
longitudinally upon application of sufficient longitudinal force
and located with respect to the slip ring so that application of
sufficient longitudinal force on the one or more wedge rings
operates to drive the slip ring radially outward; wherein: the one
or more wedge rings each comprise a wedge-like shape; the
expandable plug seat has an unset configuration and a set
configuration; in the unset configuration, the slip ring has an
initial outer diameter that is less than the inner diameter of the
casing; and in the set configuration, the outer diameter of the
slip ring is configured to contact the inner diameter of the casing
with sufficient force to hold the slip ring in place during
subsequent operations.
2. The device of claim 1, wherein the one or more wedge rings each
comprise a vertex having an angle ranging from about 3-20
degrees.
3. The device of claim 1, wherein the expandable slip ring
comprises an external elastomeric seal.
4. The device of claim 1, wherein the slip ring is configured to
expand by plastic deformation radially outward into contact with
the casing of the wellbore; and wherein, in the set configuration,
the outer diameter of the slip ring contacts the inner diameter of
the casing with sufficient force to form a seal therebetween.
5. The device of claim 1, wherein the slip ring is configured to
expand by elastic deformation radially outward into contact with
the casing of the wellbore; and wherein, in the set configuration,
the outer diameter of the slip ring contacts the inner diameter of
the casing with sufficient force to form a seal therebetween.
6. The device of claim 1, wherein the slip ring comprises an outer
surface, and the outer surface comprises a plurality of anchoring
teeth for securely attaching the slip ring in place on the inner
surface of the casing.
7. The device of claim 1, wherein the slip ring comprises an outer
surface and a plurality of slots extending longitudinally and
located radially around a circumference of the outer surface of the
slip ring.
8. The device of claim 1, wherein the device consists essentially
of only the slip ring and the one or more wedge rings.
9. The device of claim 1, wherein the one or more wedge rings are
formed of dissolvable material.
10. The device of claim 1, wherein the slip ring is formed of
dissolvable material.
11. The device of claim 9, wherein the slip ring is formed of
dissolvable material.
12. The device of claim 1, further comprising a ball configured to
seat on the one or more wedge rings and formed of dissolvable
material.
13. The device of claim 1, wherein the device is configured to be
made-up into a tool string with a wireline-conveyed power charge
setting tool.
14. The device of claim 1, further comprising a mandrel and a lock
ring, and wherein the mandrel comprises a ball seat and an angled
outer surface portion located and oriented to work in conjunction
with the wedge ring to drive the slip ring radially outward from
the unset position to the set position when sufficient longitudinal
force is applied to the wedge ring.
15. The device of claim 1, wherein the one or more wedge rings
comprise two wedge rings; and wherein, in the unset configuration,
one wedge ring is located below the slip ring and one wedge ring is
located above the slip ring.
16. The device of claim 1, wherein the one or more wedge rings
comprise a single wedge ring; and wherein, in the unset
configuration, the wedge ring is located above the slip ring.
17. A method of performing downhole operations within a cased
wellbore using a plug seat, wherein the plug seat includes a slip
ring and one or more wedge rings located with respect to the slip
ring so that application of sufficient longitudinal force on the
one or more wedge rings operates to drive the slip ring radially
outward, the method comprising the steps of: applying a sufficient
longitudinal force onto the one or more wedge rings, thereby
deforming the slip ring radially outward into contact with the
casing.
18. The method of claim 17, wherein the slip ring deforms
plastically upon application of sufficient force via the one or
more wedge rings, until the slip ring contacts the casing of the
wellbore to securely affix the plug seat to the casing.
19. The method of claim 17, wherein the slip ring deforms
elastically upon application of sufficient force via the one or
more wedge rings, until the slip ring contacts the casing of the
wellbore to securely affix the plug seat to the casing.
20. The method of claim 17, wherein the longitudinal force is
applied to the one or more wedge rings by a wireline-conveyed power
charge setting tool.
21. The method of claim 17, wherein the one or more wedge rings
comprise an upper wedge ring located above the slip ring; the
method further comprising landing a dissolvable ball on the upper
wedge ring.
22. The method of claim 21, wherein the ball dissolves due to
exposure to well conditions over time, thereby opening the wellbore
without the need for drilling.
23. The method of claim 17, further comprising making-up a tool
string comprising the plug seat, a wireline-conveyed power charge
setting tool, and a perforating gun assembly.
24. The method of claim 23, further comprising positioning the plug
seat in the wellbore, setting the plug seat using the
wireline-conveyed power charge setting tool, and perforating the
well casing, all in a single trip downhole.
25. The method of claim 24, wherein the wellbore comprises a
horizontal portion, having a toe and a heel; the method further
comprising repeatedly setting plug seat, perforating the wellbore,
sealing the wellbore by landing ball on the plug seat, and
fracturing the wellbore using a plurality of plug seats and balls
proceeding from the toe of the horizontal portion of the wellbore
towards the heel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional of and claims benefit
under 35 U.S.C. .sctn.119 to co-pending U.S. Provisional Patent
Application Ser. No. 62/067,594, filed on Oct. 23, 2014, and
entitled "Expandable Plug Seat", which is hereby incorporated by
reference for all purposes as if reproduced in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not applicable.
BACKGROUND
[0004] Conventional hydraulic fracturing operations (for drilled
wells, such as oil and gas wells) typically use drillable zonal
isolation devices (such as composite frac plugs) as the preferred
method for treating and completing multi-zone horizontal wells. In
application, such frac plugs would be located and set within the
completion liner (e.g. cased well) one at a time. After placement
of each frac plug, high pressure fracturing would be carried out in
the reservoir upstream of the plug. Once all fracturing operations
have been completed for the well, the plugs would then be drilled
out to open the completion liner to production.
[0005] These conventional fracturing operations can be quite time
consuming and costly, however. Additionally, there is the risk that
it might not be possible to drill out the frac plugs located
furthest in the toe of the horizontal well (e.g. furthest into the
well and away from the head of the well), for example due to pipe
lockup. In such instances, the operator would lose production for
the intervals of the well not drilled out (resulting in a less
efficient or productive well). The presently disclosed embodiments
may solve one or more of these problems by providing an improved
plugging technique, which may not require drill out in order to
open the completion liner to full production. The presently
disclosed embodiments may also provide for improved plug seat
setting. Persons of ordinary skill in the art field will appreciate
these and other possible benefits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] For a more complete understanding of the present disclosure,
reference is now made to the following brief description, taken in
connection with the accompanying drawings and detailed description,
wherein like reference numerals represent like parts.
[0007] FIGS. 1A-1 through 1A-3 and 1B-1 through 1B-3 illustrates
two similar embodiments of an expandable plug seat, having a slip
ring and two wedge rings, with FIG. 1A-1 illustrating the first
embodiment of a plug seat in unset configuration, FIG. 1A-2
illustrating the plug seat of FIG. 1A-1 in set configuration, and
FIG. 1A-3 illustrating a ball seated on the upper wedge ring of the
set plug seat of FIG. 1A-2 (thereby sealing the wellbore); FIG.
1B-1 illustrates a second embodiment of a plug seat in an unset
configuration, FIG. 1B-2 illustrates the plug seat of FIG. 1B-1 in
a set configuration, and FIG. 1B-3 illustrates a ball seated on the
upper wedge ring of the set plug seat of FIG. 1B-2 (thereby sealing
the wellbore);
[0008] FIGS. 2A-1 through 2A-3 illustrates an exemplary plug seat
device made-up into a tool string having a wireline-conveyed power
charge setting tool (e.g. a wireline pressure setting assembly),
with FIG. 2A-1 showing the top end view of the tool string when the
plug seat is in its unset configuration, FIG. 2A-2 showing the
longitudinal cross-section view A-A of the tool string, and FIG.
2A-3 showing a radial cross-sectional view B-B of the tool string
in unset configuration; and FIG. 2B-1 showing the top end view of
the tool string when the plug seat device is in its set
configuration, FIG. 2B-2 showing the longitudinal cross-section
view C-C of the tool string in its set configuration, and FIG. 2B-3
showing a radial cross-sectional view D-D of the tool string in set
configuration;
[0009] FIGS. 3A-1 and 3A-2 and 3B-1 and 3B2 illustrate an
alternative embodiment of a plug seat, having a slip ring and only
one wedge ring/cone (along with additional elements), with FIG.
3A-1 showing an exterior side view of the plug seat in unset
configuration and FIG. 3A-2 showing a partial cutaway cross-section
view of the unset plug seat, and FIG. 3B-1 showing an exterior side
view of the plug seat in set configuration and FIG. 3B-2 showing a
partial cutaway cross-section view of the set plug seat;
[0010] FIGS. 4A-D illustrate schematically a method of employing
the plug seat downhole, with FIG. 4A showing pumping the plug seat
to desired depth on wireline and using a setting tool to set the
plug seat in place, FIG. 4B illustrates perforating the desired
zone above the set plug seat, dropping and pumping a ball to seal
the wellbore at the plug seat, and conducting fracturing operations
in the well above the set plug seat, FIG. 4C shows how this process
may be repeated multiple times until all desired zones of the well
have been fractured, and FIG. 4D illustrates how over time the
dissolvable ball may dissolve to open the completion liner (e.g.
cased wellbore) to production;
[0011] FIGS. 5A-1 through 5A-4 and FIGS. 5B-1 through 5B-4
illustrate yet another alternative embodiment of a plug seat,
having a slip ring and two wedge rings similar to FIGS. 1A-1
through 1A-3 and 1B-1-1B-3 (but for example, optionally without an
external seal on the slip ring), with FIG. 5A-1 showing a partial
cut-away cross-section view of an exemplary tool string with the
plug seat in unset configuration, FIG. 5A-2 showing a cross-section
of the tool string of FIG. 5A-1, FIG. 5A-3 showing a side view of
the unset plug seat of FIG. 5A-1, and FIG. 5A-4 showing a
cross-section view of the unset plug seat of FIG. 5A-3; and FIG.
5B-1 showing a partial cut-away cross-section view of the exemplary
tool string with the plug seat in set configuration, FIG. 5B-2
showing a side view of the set plug seat of FIG. 5B-1 (after
application of sufficient force on the wedge rings deforms the slip
ring outward into set configuration), FIG. 5B-3 showing a
cross-section view of the set plug seat of FIG. 5B-2, and FIG. 5B-4
showing a cross-section view of the set plug seat of FIG. 5B-3 with
a ball seated on the upper wedge ring of the plug seat (thereby
blocking fluid flow through the longitudinal bore of the plug seat
and/or the cased wellbore in which the plug seat is set/affixed);
and
[0012] FIGS. 6A-1 through 6A-3 and 6B-1 through 6B-2 illustrate
still another alternative embodiment of a plug seat, having a slip
ring and only one wedge ring, with FIG. 6A-1 showing a partial
cut-away cross-section view of an exemplary tool string with a plug
seat in the unset configuration, FIG. 6A-2 shows a side view of the
unset plug seat of FIG. 6A-1, and FIG. 6A-3 shows a cross-section
of the unset plug seat of FIG. 6A-2; and FIG. 6B-1 showing a
cross-section of the set plug seat (after application of sufficient
force on the wedge ring deforms the slip ring outward into set
configuration), and FIG. 6B-2 shows a cross-section of the set plug
seat of FIG. 6B-1 with a ball seated on the wedge ring of the plug
seat (thereby blocking fluid flow through the longitudinal bore of
the plug seat and/or the cased wellbore in which the plug seat is
set/affixed).
DETAILED DESCRIPTION
[0013] It should be understood at the outset that although
illustrative implementations of one or more embodiments are
illustrated below, the disclosed systems and methods may be
implemented using any number of techniques, whether currently known
or not yet in existence. The disclosure should in no way be limited
to the illustrative implementations, drawings, and techniques
illustrated below, but may be modified within the scope of the
appended claims along with their full scope of equivalents.
[0014] The following brief definition of terms shall apply
throughout the application:
[0015] The term "up", "uphole", "above", or the like, when used in
reference to well or the tool string for example, shall mean
towards the surface or towards the top or away from the end/toe of
the well; similarly, the term "down", "downhole", "below", or the
like shall mean away from the surface or towards the bottom or
end/toe of the well;
[0016] The term "ring" shall, when used in reference to an element
for use within a well or tool string for example, typically mean
that the element has a hole, opening, or longitudinal bore
therethrough (for example, of the sort which might allow fluid flow
through the element), and typically such bore would be located
approximately along the central (longitudinal) axis of the
element;
[0017] The term "comprising" means including but not limited to,
and should be interpreted in the manner it is typically used in the
patent context;
[0018] The phrases "in one embodiment," "according to one
embodiment," and the like generally mean that the particular
feature, structure, or characteristic following the phrase may be
included in at least one embodiment of the present invention, and
may be included in more than one embodiment of the present
invention (importantly, such phrases do not necessarily refer to
the same embodiment);
[0019] If the specification describes something as "exemplary" or
an "example," it should be understood that refers to a
non-exclusive example;
[0020] The terms "about" or approximately" or the like, when used
with a number, may mean that specific number, or alternatively, a
range in proximity to the specific number, as understood by persons
of skill in the art field (for example, +/-10%); and
[0021] If the specification states a component or feature "may,"
"can," "could," "should," "would," "preferably," "possibly,"
"typically," "optionally," "for example," "often," or "might" (or
other such language) be included or have a characteristic, that
particular component or feature is not required to be included or
to have the characteristic. Such component or feature may be
optionally included in some embodiments, or it may be excluded.
[0022] Embodiments may relate generally to methods and devices for
setting a plug seat within a downhole well, for example in advance
of fracing operations. The disclosed expandable plug seat
embodiments typically include an expandable slip ring (which in
some embodiments may optionally have an elastomeric seal on its
exterior) and one or more wedge rings (and in some embodiments, the
plug seat may consist essentially of or consist only of a slip ring
and one or more wedge rings). For example, typical embodiments
might include dual wedge rings, with an upper wedge ring located
above the slip ring and a lower wedge ring located below the slip
ring. In other embodiments, a single wedge ring might be located
with respect to (for example, above) the slip ring. To set the
expandable plug seat in place within the casing of the wellbore,
longitudinal force would typically be applied to each of the one or
more wedge rings, thereby deforming the expandable slip ring and
driving it radially outward and into contact with the casing in the
wellbore (due to the interaction of the wedge-like shape of the one
or more wedge rings with the inner (radial) surface of the slip
ring). In some embodiments, deformation of the slip ring may be
plastic and/or elastic (and most typically there would be plastic
deformation of the slip ring). In some embodiments, the expandable
plug seat may be used with a dissolvable ball (which might be
either dissolvable metal or dissolvable polymer), which can be
pumped to seat onto the plug seat device (for example, directly on
the upper wedge ring). Once the downstream section of the well has
been isolated in this manner, hydraulic fracturing operations can
commence. Eventually, the ball may dissolve, allowing access to the
wellbore without the need to drill the plug. And in some
embodiments, one or more element of the plug seat may also
dissolve, providing additional radial space in the well (for
example, for future production).
[0023] So for example, in an embodiment, the plug seat device might
comprise an expandable (for example, solid) slip ring (which
optionally may have an external elastomeric seal), wherein the
expandable slip ring is operable to expand by deforming
(plastically and/or elastically) radially outward (upon application
of sufficient force on its inner diameter); and one or more wedge
rings (for example, operable to slide longitudinally and) located
with respect to the slip ring so that application of sufficient
longitudinal force on the wedge rings operates to drive the slip
ring radially outward (e.g. causing the deformation of the slip
ring). Typically, each wedge ring would comprise a wedge-like shape
(for example, with the outer diameter of the wedge ring at one end
(typically the end farther away from the slip ring in the unset
configuration) being larger than the outer diameter of the wedge
ring at the opposite end (typically the end closer to the slip ring
in the unset configuration)) having an angled vertex/outer surface
ranging from about 5-10 degrees (or alternatively 3-20 degrees),
for example. And, the slip ring typically would be operable to
deform (plastically and/or elastically) radially outward upon
application of force from the wedge rings (for example, when
sufficient longitudinal force is applied to the one or more wedge
rings, driving the one or more wedge rings further into the slip
ring, and thereby driving the slip ring radially outward due to the
wedge-shape of the wedge rings). Furthermore, the expandable plug
seat typically would have an (initial) unset configuration and a
set configuration (e.g. after application of sufficient
longitudinal force on the wedge rings has driven the slip ring
radially outward into contact with the inner surface of the casing
and/or wellbore, or until the slip ring has been driven outward so
that is outer diameter is approximately equal to the inner diameter
of the cased wellbore in question). In the unset configuration, the
slip ring typically has an initial outer diameter that is less than
the inner diameter of the casing and/or wellbore (for example,
allowing the plug seat device to be run downhole); one wedge ring
(e.g. the upper wedge ring) is typically located above the slip
ring; and optionally one wedge ring (e.g. the lower wedge ring) may
be located below the slip ring, for example with (only) the vertex
of each wedge ring initially being located within (e.g. radially
inward of and contacting the inner diameter/surface of) the slip
ring (such that the remainder of the wedge rings typically would be
located outside the slip ring and would not contact the slip ring
in the unset configuration). So, the plug seat would be
transitioned from its unset configuration to its set configuration
by application of sufficient longitudinal force on the one or more
wedge rings (for example, sliding the wedge rings longitudinally
towards each other and/or inward of the slip ring--for example,
with more of the wedge ring(s) located within the slip ring). In
the set configuration, the one or more wedge rings would have been
driven (and are located) further within the slip ring (for example,
with the upper wedge ring being driven downward into the slip ring
and the lower wedge ring being driven upward into the slip ring),
thereby driving the slip ring radially outward via deformation
(plastic and/or elastic) of the slip ring until the outer diameter
of the slip ring contacts the inner diameter of the casing and/or
wellbore with sufficient force to hold the slip ring in place
during fracing operations (e.g. the outer diameter of the slip ring
in the set configuration is approximately equal to and contacts the
inner diameter of the casing and/or wellbore). In other words, the
slip ring may be set (e.g. moved from the unset configuration to
the set configuration) by application of sufficient longitudinal
force on the one or more wedge rings, driving the one or more wedge
rings longitudinally further within the slip ring. Thus, the slip
ring is configured so that it is operable to transition from its
unset position/shape/size (with an outer diameter less than the
inner diameter of the cased wellbore, for example) to its set
position/shape/size (with outer diameter equal to the inner
diameter of the cased wellbore, for example).
[0024] The slip ring may optionally have a plurality of anchoring
teeth on its outer surface, configured to more securely attach the
slip ring in place on the inner surface of the cased wellbore (in
the set configuration), for example with the teeth
operable/configured to penetrate the casing slightly upon setting
of the plug seat (for example, penetrating about 0.010-0.030
inches). The slip ring may optionally also have a plurality of
longitudinal slots (which typically might not penetrate all the way
through the slip ring, but merely would be indentations forming a
thinner wall cross-section at locations in the slip ring--although
in other embodiments, the slots could form openings in the slip
ring) which may be located radially around the circumference of
(e.g. the outer surface) of the slip ring. For example, each such
longitudinal slot might have a width of about 0.25 inches, a length
of about 2.17 inches, and a depth to not fully penetrate the slip
ring, but rather to leave a thin web (for example about 0.030
inches thick). An exemplary embodiment might have about 15 such
slots spaced evenly around the exterior circumference of the slip
ring. And while some embodiments of the slip ring may have an
elastomeric (or other) seal element located on its outer/exterior
surface, in other embodiments the slip ring may be configured to
effectively form a seal when driven into contact with the cased
wellbore (e.g. an effective seal might be formed without the use of
any such separate seal element).
[0025] Typically, the plug seat device does not contain any
additional retention elements (such as a body lock ring or mandrel)
beyond the slip ring and/or wedge rings (so for example, the plug
seat may consist essentially of or consist of only the slip ring
and one or more wedge rings). Additionally, typically the plug seat
device would not contain a separate ball seat (e.g., the ball could
be landed directly on the upper wedge ring). So for example, the
plug seat of some embodiments might consist essentially of (or
consist of) only the slip ring and one or more wedge rings. In some
embodiments, the slip ring may comprise an outer surface, which may
comprise a plurality of anchoring teeth/barbs/ridges in some
embodiments for securing/attaching/anchoring the slip ring in place
on the inner surface of the casing and/or wellbore (providing a
better lock/grip than friction alone). Additionally, the optional
elastomeric seal (typically located on the outer/exterior surface
of the slip ring in embodiments having such a seal) typically would
be configured/operable to effectively seal fluid flow about the
exterior of the plug seat device when set in place within the
casing (although in other embodiments, such an effective seal might
be formed by contact of the slip ring body itself against the cased
wellbore, without any need for a separate seal element). Typically,
the optional seal diameter would be slightly larger than the outer
diameter of the slip ring (for example, larger than the slip teeth
diameter) to allow for compression when set. Such a seal might be
rated for 10,000 psi differential pressure at 350 degrees
Fahrenheit. Exemplary seal materials might be either Nitrile or
Aflas.
[0026] Often, the plug seat device might be operable or configured
to work in conjunction with a sealing ball/plug. Such a ball might
be formed of a dissolvable material (which might be metallic or
polymeric material operable to dissolve over time (for example,
approximately 1-5 days) under exposure to elevated temperature (for
example a range of approximately 150-250 degrees Fahrenheit) and
either brine (for example KCL brine) or acid (for example
approximately 2-5 pH range)). One example of such a dissolvable
material might be TervAlloy or similar materials sold by Terves,
Inc. Another example of such dissolvable material might be polymer
from Bubbletight LLC. In some such embodiments, the slip ring
and/or one or more wedge rings in the set configuration might be
configured to have an inner diameter sufficiently large to allow
for access to the wellbore via tubing or wireline (such that they
do not need to be drilled out to allow for production of the well).
In some other embodiments, the one or more wedge rings and/or the
slip ring of the plug seat might also be formed of such dissolvable
material (e.g. material operable to dissolve over time (for
example, approximately 1-5 days) under exposure to elevated
temperature (for example a range of approximately 150-250 degrees
Fahrenheit) and either brine (for example KCL brine) or acid (for
example approximately 2-5 pH range)). For example, the one or more
wedge rings and/or slip ring might be formed of the same
dissolvable material as the sealing ball/plug. This would allow the
plugged wellbore to open (after the timeframe needed for fracing,
for example) without the need for drilling. And in some
embodiments, the plug seat device may be configured/operable to be
made-up into a tool string with a wireline-conveyed power charge
setting tool (e.g. a wireline pressure setting assembly) and/or a
perforating gun assembly. Such a tool string may allow the plug
seat to be set and the wellbore to be perforated in one wireline
trip downhole (e.g. prior to fracturing the zone).
[0027] FIGS. 1A-1 through 1A-3 illustrate a first embodiment of a
plug seat device 10, while FIGS. 1B-1 through 1B-3 illustrate a
second, similar embodiment of a plug seat device (with the primary
difference between the embodiments of FIGS. 1A-1 through 1A-3 and
1B-1 through 1B-3 being the angle of the wedge rings and/or the
depth that the wedge rings slide within the slip ring during
setting). FIG. 1A-1 illustrates an exemplary plug seat device 10 in
its unset configuration (e.g. its initial configuration, allowing
it to be run downhole into position within the wellbore). The plug
seat device of FIG. 1A-1 has a slip ring 20 and two wedge rings 30
and 40. The slip ring 20 of FIG. 1A-1 is configured as a solid ring
operable to deform (e.g. plastically and/or elastically) radially
outward upon application of force from the wedge rings (e.g. when
sufficient longitudinal force is applied to the wedge rings), and
in the unset configuration of FIG. 1A-I, the slip ring 20 has an
outer diameter that is less than the inner diameter of the
casing/wellbore 5 (to provide sufficient clearance so that the plug
seat can be run downhole). For example, when the wedge rings 30, 40
(each of which may be operable to slide longitudinally upon
application of sufficient longitudinal force) are driven towards
the slip ring 20 (longitudinally), the angled surfaces of the wedge
rings 30, 40 would drive the slip ring 20 radially outward and into
contact with the wellbore/casing 5. By way of example, the slip
ring 20 of FIGS. 1A-1 through 1A-3 and 1B-1 through 1B-3 might be
formed of AISI 8620 material (fully annealed), 10-12% elongation,
which should provide sufficient plasticity to allow for the slip
ring to transition from the unset configuration/position to the set
configuration/position. The slip ring 20 of FIG. 1A-1 typically has
an elastomeric seal 22 (although this may be optional) about its
outer/exterior surface (for example, extending circumferentially
about the exterior of the slip ring), and the elastomeric seal 22
is configured/capable/operable of providing an effective seal to
prevent fluid flow about the exterior of the slip ring 20 in its
set configuration. Furthermore, the slip ring of FIG. 1A-i
typically would have a plurality of gripping or anchoring elements
25 (typically termed teeth) on its exterior surface (for example,
teeth, barbs, or ridges operable to bite/dig into the inner
diameter surface of the casing/wellbore 5 when the plug seat is
set, to provide a more effective hold to lock the set plug seat in
place).
[0028] In the embodiment of FIG. 1A-1, the two wedge rings 30 and
40 each typically have an angle of about 10 degrees (so for
example, the outer surface of the wedge rings might have an angle
of about 10 degrees with respect to a line parallel to the
centerline of the plug seat device). Typically, in the unset
configuration shown in FIG. 1A-1, one wedge ring would be located
on either side of the slip ring 20 (for example, with an upper
wedge ring 30 located above the slip ring 20, and the lower wedge
ring 40 being located below the slip ring 20), and typically only
the vertex 32, 42 of the wedge rings would be located initially
within the slip ring 20 and contacting the inner surface of the
slip ring (e.g. the remainder of the wedge rings 30, 40 would
initially be located outside the slip ring, for example
longitudinally). In other words, there is a gap of space
longitudinally between the vertexes of the wedge rings 30 and 40 in
the unset configuration (and the gap typically would be
approximately the length of the slip ring 20). And typically, the
wedge rings 30, 40 would have an outer diameter that at their
furthest end is less than the inner diameter of the casing/wellbore
5 (to again ensure that the plug seat device as a whole has an
outer diameter that is less than the inner diameter of the
casing/wellbore 5, so that there is sufficient clearance to allow
for running of the plug seat device downhole). For example in the
unset configuration the outer diameter (of the far end of) the
wedge rings 30, 40 would typically be spaced away from the inner
diameter of the casing/wellbore 5 about a distance less than the
thickness of the slip ring 20). By way of example, the wedge rings
30, 40 would typically be formed of a material which is
sufficiently strong to drive the slip ring outward (under
application of sufficient longitudinal force), such as AISI 4140
material with 110 minimum yield strength.
[0029] FIG. 1A-2 illustrates the same plug seat device from FIG.
1A-1 in its set configuration (e.g. after application of sufficient
longitudinal force on the wedge rings, to drive the slip ring
radially outward and into contact with the casing/wellbore, thereby
fixing the plug seat 10 into position in the well). Longitudinal
force typically would be applied to the top of the upper wedge ring
30 and to the bottom of the lower wedge ring 40, thereby driving
the wedge rings closer together and further into the slip ring 20.
By way of example, the setting longitudinal force for some
embodiments might be approximately 10,000-30,000 lbsF. As the wedge
rings 30, 40 are driven inward, their angled surfaces act to
transmit the force to the slip ring 20, thereby driving the slip
ring 20 radially outward until it contacts and is set in the
casing/wellbore 5. So in FIG. 1A-2 (which shows the plug seat in
its set configuration), the wedge rings 30, 40 are closer together,
with more of the wedge rings 30, 40 length located within the slip
ring 20. The slip ring 20 of FIG. 1A-2 has a larger outer diameter,
which is approximately equal to the inner diameter of the
casing/wellbore 5. This allows the anchoring teeth 25 on the
exterior surface of the slip ring to anchor securely to the
casing/wellbore 5 (in a securely affixing manner), and the
elastomeric seal 22 on the exterior of the slip ring 20 to fit
snuggly (in a sealing manner) against the inner surface of the
casing/wellbore 5.
[0030] FIG. 1A-3 then shows how the open longitudinal bore of the
set plug seat device 10 may be sealed by seating a ball 50 onto the
upper wedge ring 30. This would typically be done in advance of
fracturing operations uphole of the plug seat 10. The ball 50 would
typically have a diameter larger than the inner diameter of the
wedge ring 30, and would typically seat directly onto the upper
wedge ring 30. In some embodiments, the ball 50 would be formed of
dissolvable materials. For example, the ball 50 might be formed of
dissolvable metallic material operable to dissolve over time (for
example, approximately 1-5 days) under exposure to elevated
temperature (for example a range of approximately 150-250 degrees
Fahrenheit) and either brine (for example KCL brine) or acid (for
example approximately 2-5 pH range). One example of such a material
might be TervAlloy or similar materials sold by Terves, Inc.
Alternatively, the ball might be made of a dissolvable polymer
material, such as made by Bubbletight LLC for example. In some
embodiments, the ball might have a protective coating, for example
to delay dissolution of the ball (although in other embodiments,
the well chemistry might be used (perhaps along with a protective
coating) to delay or control the timing of dissolution). The use of
such a dissolvable ball 50 might allow for the plug seat 10 to be
temporarily sealed by a ball, but to be operable to open at a later
time without the need for drilling. In some embodiments, the wedge
rings 30, 40 and/or slip ring 20 might also be formed of similar
dissolvable materials (which might allow for a larger bore without
the need for drilling).
[0031] FIGS. 1B-1 through 1B-3 illustrate a similar plug seat 10,
having wedge rings 30, 40 with an angle of about 5 degrees (e.g.
the outer surface of the wedge rings would have an angle of about 5
degrees with respect to a line parallel to the centerline of the
plug seat 10). FIG. 1B-I shows the plug seat in unset
configuration, FIG. 1B-2 shows the plug seat in set configuration,
and FIG. 1B-3 shows the plug seat when sealed by a ball 50. In FIG.
1B-2, the wedge rings 30, 40 may be driven together until their
vertexes contact. It should be understood that sufficient
longitudinal force applied to the wedge rings may effectively set
the slip ring in the casing/wellbore, as discussed above.
[0032] In some embodiments, the plug seat 10 (for example as shown
in FIGS. 1A-1 through 1A-3 and 1B-1 through 1B-3, although other
plug seat embodiments would also apply) may be made-up into a tool
string having a wireline-conveyed power charge setting tool (e.g. a
wireline pressure setting assembly, such as Baker Style #20 WL
Setting Tool), for applying the longitudinal force required to set
the plug seat 10 in place in the casing/wellbore. For example,
FIGS. 2A-1 through 2A-3 and 2B-1 through 2B-3 illustrates such an
exemplary tool string, with FIG. 2A-1 through 2A-3 showing the tool
string when the plug seat 10 is in the unset configuration, and
FIG. 2B-1 through 2B-3 showing the tool string when the plug seat
10 is in the set configuration. FIG. 2A-1 shows a top side view of
the tool string in unset configuration, while FIG. 2A-2 shows a
longitudinal cross-sectional view A-A (showing the plug seat device
10 in unset configuration and in place in line with the setting
tool 60), and FIG. 2A-3 shows a radial cross-sectional view B-B.
FIG. 2B-1 shows a top side view of the tool string in set
configuration, while FIG. 2B-2 shows a longitudinal cross-sectional
view C-C (showing the plug seat device 10 in set configuration and
in place in line with the setting tool 60), and FIG. 2B-3 shows a
radial cross-sectional view D-D. In some embodiments, the tool
string may also include a perforating gun (not shown, but for
example, located above the plug seat 10). Such a tool string
configuration might allow setting of the plug seat and perforating
of the well using only a single trip downhole (prior to fracturing
the zone). Then, for example, a dissolvable ball might be seated on
the plug seat to allow for fracing operations (for example, during
the time before the ball and/or wedge rings dissolve).
[0033] FIGS. 3A-1 through 3A-2 and 3B-1 through 3B-2 illustrate an
alternative embodiment of a plug seat. The plug seat of FIGS. 3 A-1
through 3A-2 and 3B-1 through 3B-2 comprises a dissolvable mandrel
or body, a dissolvable tapered cone/wedge ring (similar to that
discussed above), a dissolvable lock ring, and/or a solid
expandable slip ring (similar to the slip ring discussed above)
having an inner seal and an outer seal (although such seals may be
optional, with one or both being omitted from some embodiments).
The dissolvable materials might be the same or similar to those
discussed above, for example. As described above, the wedge
ring/cone would typically have a wedge-like portion having an
angled outer surface (for example, ranging from about 3-20
degrees). The mandrel has a flow-through passage, which may allow
flow bypass prior to fracturing operations. The mandrel also
features a ball seat on the uphole end. Typically, the mandrel
would also comprise an angled outer surface portion located (below
the slip ring) and oriented to work in conjunction with the wedge
ring (when sufficient longitudinal force is applied to the wedge
ring) to drive the slip ring radially outward during setting of the
plug seat (e.g. causing plastic deformation of the slip ring as it
moves from the unset position to the set position). For example, in
the embodiment of FIGS. 3 A-1 through 3A-2 and 3B-1 through 3B-2
the angled outer surface portion of the mandrel typically might
match the angle of the wedge ring and/or be 3-20 degrees. Similar
to the embodiments described above, the plug seat of FIGS. 3 A-2
and 3B-1 through 3B-2 has an initial, unset configuration, and a
set configuration. FIGS. 3A-1 through 3A-2 show the plug seat in
its unset configuration, while FIGS. 3B-1 through 3B-2 show the
plug seat in its set configuration. To set the plug seat in place
in the wellbore, a longitudinal force would be applied to the
dissolvable lock ring and/or tapered cone/wedge ring while the
mandrel is held in place. The force would serve to deform (e.g.
plastically and/or elastically) the expandable solid slip ring,
driving it radially outward until it contacts the inner diameter of
the casing/wellbore. Once the plug seat is anchored, a dissolvable
ball (which, for example, might be formed of the same dissolvable
material as the dissolvable elements of the plug seat) may be
dropped and pumped to seat on the mandrel (e.g. the ball seat) of
the plug seat, to allow for fracturing operations. Over time, the
dissolvable elements of the plug seat (and the ball) will dissolve,
for example leaving only the slip ring and/or seals behind (which
should not inhibit production flow and typically would have a
sufficiently large inner diameter to allow for access to the
wellbore via tubing and/or wireline). In other embodiments,
however, even the slip ring might be formed of dissolvable material
(for example, similar to that described above), such that only the
elastomeric seals (if any) might be left un-dissolved in the
wellbore. In some embodiments, the ball and/or dissolvable elements
of the plug seat device might have a protective coating, for
example to delay dissolution (although in other embodiments, the
well chemistry might be used (perhaps along with a protective
coating) to delay or control the timing of dissolution).
[0034] FIGS. 5A-1 through 5A-4 illustrate an alternative embodiment
of a plug seat (similar to that shown in FIGS. 1A-1 through 1A-3
and 1B-1 through 1B-3 for example) in unset configuration, while
FIGS. 5B-1 through 5B-4 illustrate the same embodiment in set
configuration. FIGS. 5A-1 and 5A-2 illustrate the plug seat 510
within an exemplary tool string (e.g. the plug seat may be
removably coupled to the tool string, for example with a
wireline-conveyed power charge setting tool), with FIG. 5A-1
showing a partial cut-away cross-section view of the tool string
and FIG. 5A-2 showing a full cross-section of the tool string (in
unset configuration). FIG. 5A-3 illustrates (in a side view) just
the plug seat 510 in unset configuration, while FIG. 5A-4
illustrates the same unset plug seat 510 via cross-section view. So
as clearly shown in FIGS. 5A-3 through 5A-4, the plug seat 510 has
two wedge rings 530 and 540 configured to interact (via
longitudinal sliding) with the slip ring 520 (typically with one
wedge ring 530 located above the slip ring 520, and one wedge ring
540 located below the slip ring 520). In other words, in FIG. 5A-4
(with the plug seat unset), only the vertex of each wedge ring 530,
540 is initially located within the slip ring 520, but the wedge
rings 530, 540 are configured to slide further into the slip ring
520 upon application of sufficient longitudinal force (e.g.
shifting from unset to set configuration).
[0035] The slip ring 520 in this unset configuration has an outer
diameter which is configured to be less than the inner diameter of
the cased wellbore (for which the plug seat is intended to be
used), and is operable/configured to deform (plastically and/or
elastically) under application of force from the wedge rings 530,
540 (in order to shift outward from the unset to the set
configuration/position). The wedge rings 530, 540 also have a
maximum outer diameter which is less than the inner diameter of the
cased wellbore (although typically the difference between the
maximum outer diameter of the wedge rings 530, 540 and the inner
diameter of the cased wellbore is less than or equal to the
thickness of the slip ring, for example after deformation to the
set position). In FIG. 5A-3, the slip ring 520 comprises a
plurality of teeth 525 on its outer/exterior surface, typically
located about the circumference of the slip ring outer surface.
While the teeth 525 may be oriented in various ways (e.g. to form a
secure hold onto the cased wellbore), in FIG. 5A-3 the teeth on the
upper portion of the slip ring 520 face one direction (for example,
angled downward), while the teeth on the lower portion of the slip
ring 520 may face another direction (for example, angled upward).
The slip ring 520 of FIG. 5A-3 also comprises a plurality of
longitudinal slots 527 located evenly about its outer surface
circumference. For example, in FIG. 5A-3, there may be 15 such
slots (which typically would not penetrate the slip ring in the
embodiment of FIG. 5A-3 (although in other embodiments, the slots
could penetrate the slip ring to form openings), but are merely
locations of thinness of the slip ring 520, such as indentations),
with each slot 527 typically having a width of about 0.25 inches, a
length of about 2.17 inches, and a depth to not fully penetrate the
slip ring, but rather leave a thin web (for example about 0.030
inches thick).
[0036] As discussed above, the slip ring 520 is typically made of a
material operable to deform from unset to set configuration upon
application of sufficient force (radially) via the wedge rings 530,
540. And typically, the wedge rings 530, 540 and/or the slip ring
520 may be formed of dissolvable material (as discussed above). On
the other hand, if the wedge rings and/or slip ring are not
dissolvable (for example, if only a dissolvable ball is used to
close the bore), then they (e.g. one or both) may instead have a
bore (e.g. an inner diameter) which is sufficiently large in the
set position/configuration to allow for access to the wellbore
(below the set plug seat) via tubing or wireline, such that they do
not need to be drilled out to allow for downhole work/production
below the set plug seat in the wellbore. And as discussed above,
the wedge rings 530, 540 typically have a wedge-like shape (for
example, in cross-section), with the outer surface having an angle
(for example, with respect to a line parallel to the longitudinal
bore centerline) ranging from about 3-20 degrees (or for example,
alternately 5-20, 5-10, or 10-20 degrees). And as discussed above,
the seat plug of FIGS. 5A-1-5A-4 and 5B-1-5B-4 may consist
essentially of or consist of only the slip ring 520 and wedge rings
530, 540.
[0037] Upon application of sufficient longitudinal force on the
wedge rings 530, 540 (for example, with the setting tool pressing
down on the upper wedge ring 530 directly, while the lower wedge
ring 540 is pressed up against by an insert 508 which interacts
with the setting tool in the tool string to transmit upward
longitudinal force to the lower wedge ring), the wedge rings 530,
540 move (e.g. slide longitudinally) further into the slip ring
(for example, towards each other), with their wedge-like shape
driving the slip ring 520 to deform (plastically and/or
elastically) outward to the set configuration/position as shown in
FIGS. 5B-1 through 5B-4 for example (when its outer diameter is
configured to be approximately equal to the inner diameter of the
cased wellbore, providing a secure attachment of the plug seat to
the cased wellbore, as discussed above). FIG. 5B-1 illustrates in
partial cross-section the plug seat 510 (in set configuration) in
place within a tool string, while FIG. 5B-2 shows just the plug
seat 510 in set configuration from a side view, FIG. 5B-3 shows the
same set plug seat 510 in cross-section, and FIG. 5B-4 shows the
set plug seat 510 with a ball 550 (typically dissolvable) seated on
the upper wedge ring 530 to close/seal the bore (for example, in
preparation for fracing). In the set configuration shown in FIGS.
5B-2 through 5B-3, the wedge rings 530, 540 have been driven closer
together and are substantially located within the slip ring 520
(e.g. the gap between the set wedge rings is much smaller than in
the unset configuration shown in FIG. 5A-4 for example). The slip
ring 520 of FIG. 5B-3 (in the set configuration) typically would
have an outer diameter approximately equal to the inner diameter of
the cased wellbore at issue. Additionally, embodiments may
optionally include a shear ring or tab (for example, attached to
the slip ring and/or the lower wedge ring) in the unset
configuration of FIG. 5A-1, which may be operable/configured to be
sheared once the setting tool provides the required setting force.
This may limit the amount of force applied to the plug seat, and
may also allow for the plug seat to disconnect from the setting
tool once set. Thus, these figures clearly illustrate an exemplary
plug seat embodiment (for example, without an external elastomeric
seal) in both the unset and set configuration, and persons of skill
would understand the construction and operation of such a plug seat
510 based on these figures.
[0038] FIGS. 6A-1 through 6A-3 illustrate another alternative
embodiment of a plug seat (similar to that shown in FIGS. 1A-1
through 1A-4 and 1B-1 through 1B-4 and/or FIGS. 3A-1 through 3A-2
and 3B-1 and 3B-2 for example) in unset configuration, while FIGS.
6B-1 through 6B-2 illustrate the same embodiment in set
configuration. FIG. 6A-1 illustrates the plug seat 610 within an
exemplary tool string (e.g. the plug seat may be removably coupled
to the tool string, for example with a wireline-conveyed power
charge setting tool), with FIG. 6A-1 showing a partial
cross-section view of the tool string (in unset configuration).
FIG. 6A-2 illustrates (in a side view) just the plug seat 610 in
unset configuration, while FIG. 6A-3 illustrates the same unset
plug seat 610 via cross-section view. So as clearly shown in FIGS.
6A-2 through 6A-3, the plug seat 610 has only one wedge ring 630
(typically located above the slip ring 620), which is configured to
interact (via longitudinal sliding) with the slip ring 620. In
other words, in FIG. 6A-3, only the vertex of the wedge ring 630 is
initially located within the slip ring 620 (in unset
configuration), but the wedge ring 630 is configured to slide
further into the slip ring 620 upon application of sufficient
longitudinal force (e.g. shifting from unset to set
configuration).
[0039] Similar to the discussion above regarding FIGS. 5A-1 through
5A-4 and 5B-1 through 5B-4, the slip ring 620 in this unset
configuration has an outer diameter which is configured to be less
than the inner diameter of the cased wellbore (for which the plug
seat is intended to be used), and is operable/configured to deform
(plastically and/or elastically) under application of force from
the wedge ring 630 (in order to shift outward from the unset to the
set configuration/position). The wedge ring 630 also has a maximum
outer diameter which is less than the inner diameter of the cased
wellbore (although typically the difference between the maximum
outer diameter of the wedge ring 630 and the inner diameter of the
cased wellbore is less than or equal to the thickness of the slip
ring, for example after deformation to the set position). In FIG.
6A-3, the slip ring comprises a plurality of teeth 625 on its
outer/exterior surface, typically located about the circumference
of the slip ring outer surface. While the teeth 625 may be oriented
in various ways (e.g. to form a secure hold onto the cased
wellbore), in FIG. 6A-3 the teeth all face one direction (for
example, angled downward). The slip ring 620 of FIG. 6A-3 also
comprises a plurality of longitudinal slots 627 located evenly
about its outer surface circumference. For example, in FIG. 6A-3,
there may be up to 15 such slots (which in this embodiment may
penetrate the slip ring 620 forming openings through the slip ring,
but which in other similar embodiments might merely be locations of
thinness of the slip ring, such as indentations), with each slot
typically having a width of about 0.25 inches and a length of about
2.17 inches (and some embodiments having a slot depth penetrating
the slip ring, while other embodiments might have a depth to not
fully penetrate the slip ring, but leaving a thin web (for example
about 0.030 inches)).
[0040] As discussed above, the slip ring 620 is typically made of a
material operable to deform from unset to set configuration upon
application of sufficient force (radially) via the wedge ring 630.
And typically, the wedge ring 630 and/or the slip ring 620 may be
formed of dissolvable material (as discussed above). On the other
hand, if the wedge ring and/or slip ring are not dissolvable (for
example, if only a dissolvable ball is used to close the bore),
then they (e.g. one or both) may instead have a bore (e.g. an inner
diameter) which is sufficiently large in the set
position/configuration to allow for access to the wellbore (below
the set plug seat) via tubing or wireline, such that they do not
need to be drilled out to allow for downhole work/production below
the set plug seat in the wellbore. And as discussed above, the
wedge ring 630 typically has a wedge-like shape (for example, in
cross-section), with the outer surface having an angle (for
example, with respect to a line parallel to the longitudinal bore
centerline) ranging from about 3-20 degrees (or for example
alternately, 5-20, 5-10, or 10-20 degrees). And as discussed above,
the seat plug of FIGS. 6A-1 through 6A-3 and 6B-1 through 6B-2 may
consist essentially of or consist of only the slip ring 620 and
wedge ring 630.
[0041] Upon application of sufficient longitudinal force on the
wedge ring 630, for example with the setting tool pressing down on
the upper wedge ring 630 directly, the wedge ring 630 moves (e.g.
slide longitudinally) further into the slip ring (for example, with
most of the length of the wedge ring located within the slip ring),
with the wedge-like shape driving the slip ring 620 to deform
(plastically and/or elastically) outward to the set
configuration/position as shown in FIGS. 6B-1 through 6B-2 for
example (when its outer diameter is configured to be approximately
equal to the inner diameter of the cased wellbore, providing a
secure attachment of the plug seat to the cased wellbore, as
discussed above). FIG. 6B-1 illustrates in cross-section just the
plug seat 610 (in set configuration), while FIG. 6B-2 shows the set
plug seat 610 with a ball 650 (typically dissolvable) seated on the
wedge ring 630 to close/seal the bore (for example, in preparation
for fracing). In the set configuration shown in FIGS. 6B-1-6B-2,
the wedge ring 630 has been driven farther into the slip ring and
is substantially located within the slip ring 620. The slip ring
620 of FIG. 6B-1 (in the set configuration) typically would have an
outer diameter approximately equal to the inner diameter of the
cased wellbore at issue. Additionally, embodiments may optionally
include a shear ring or tab (for example, attached to the slip
ring) in the unset configuration of FIG. 5A-1, which may be
operable/configured to be sheared once the setting tool provides
the required setting force. This may limit the amount of force
applied to the plug seat, and may also allow for the plug seat to
disconnect from the setting tool once set. Thus, these figures
clearly illustrate an exemplary plug seat embodiment (for example,
without an external elastomeric seal) in both the unset and set
configuration, and persons of skill would understand the
construction and operation of such a plug seat 610 based on these
figures.
[0042] One or more of the plug seat device embodiments described
above may allow for an improved method of fracturing a well,
especially for example when used in conjunction with a dissolvable
ball/plug. Typically, such a method of performing downhole
operations (such as fracing) within a (typically cased) wellbore
uses an expandable plug seat (which, for example, might include a
slip ring and one or more wedge rings located with respect to the
slip ring so that application of sufficient longitudinal force on
the wedge rings operates to drive the slip ring radially outward)
and includes the step of applying a longitudinal force onto the one
or more wedge rings (thereby driving the wedge rings towards one
another and/or deeper into the slip ring), thereby deforming (e.g.
plastically and/or elastically) the slip ring radially outward into
contact with the casing/wellbore (in order to seat the plug seat in
the casing/wellbore and/or move the plug seat from the unset
position to the set position). In some embodiments, the
longitudinal force may be applied to the wedge rings by a
wireline-conveyed power charge setting tool (e.g. a wireline
pressure setting assembly). Typically, the plug seat might not
contain any additional retention elements (such as body lock ring
or mandrel) beyond the slip ring and/or wedge ring(s).
Additionally, the plug seat typically would not contain a separate
ball seat; rather, the ball would be landed directly on the upper
wedge ring. So in some embodiments, the plug seat may consist
essentially of (or consist of) only the slip ring and one or more
wedge rings.
[0043] The method may further comprise the step of positioning the
plug seat within the wellbore (i.e. locating the plug at the proper
location downhole within the wellbore for sealing of the wellbore
for fracturing of a zone). Oftentimes, the plug seat may be run
downhole in conjunction with a wireline-conveyed power charge
setting tool (e.g. a wireline pressure setting assembly) and/or a
perforating gun assembly (e.g. all three would be run downhole
together at the same time). This may allow for more efficient
setting of the plug seat and perforating of the well (reducing the
number of separate trips run downhole). Typically, such a method
would include making-up a tool string comprising the plug seat, a
wireline-conveyed power charge setting tool (e.g. a wireline
pressure setting assembly), and/or a perforating gun assembly, and
then positioning the plug seat in the wellbore, setting the plug
seat using the wireline-conveyed power charge setting tool (e.g. a
wireline pressure setting assembly), and perforating the well
casing, all in a single trip downhole.
[0044] Once the plug seat has been set in the wellbore and the
well/casing has been perforated, the wellbore can be sealed to
allow for fracturing of the well upstream of the plug seat.
Typically, the wedge rings may comprise at least an upper wedge
ring located above the slip ring, and the method may further
comprise landing (e.g. pumping) a dissolvable ball/plug onto the
upper wedge ring (to isolate/seal the downstream section of the
well). In other words, the ball typically would land directly on
the upper wedge ring, without a separate ball seat. In some
embodiments, the ball may be formed of dissolvable material
(operable to dissolve over time (for example, approximately 1-5
days) under exposure to elevated temperature (for example a range
of approximately 150-250 degrees Fahrenheit) and either brine (for
example KCL brine) or acid (for example approximately 2-5 pH
range). One example of such a material might be TervAlloy
dissolvable metallic material or similar materials sold by Terves,
Inc. Another example of such material might be dissolvable
polymeric material by Bubbletight LLC. And in some embodiments, the
plug seat (or at least portions of the plug seat, such as the one
or more wedge rings and/or the seal ring) would be formed of
dissolvable material (for example, operable to dissolve over time
(for example, approximately 1-5 days) under exposure to elevated
temperature (for example a range of approximately 150-250 degrees
Fahrenheit) and either brine (for example KCL brine) or acid (for
example approximately 2-5 pH range). Again, exemplary materials
might be TervAlloy or similar materials sold by Terves, Inc., or
dissolvable polymeric material by Bubbletight LLC. So, the slip
ring and/or one or more wedge rings may be formed of the same
dissolvable material as the ball (or in some embodiments, the wedge
ring(s) and/or slip ring may be dissolvable, while the ball might
not be).
[0045] Once the set plug seat has been sealed (isolating the
downstream portion of the well), the method might include
fracturing a zone of the well above the set and sealed plug seat
(e.g. with the ball in place on the upper wedge ring). In most
instances, the wellbore in question would comprise a horizontal
portion (e.g. a horizontal well), having a toe and a heel.
Typically, the initial plug seat is set towards the toe of the
horizontal portion of the well (e.g. farthest downhole). The
process (for example, setting a plug seat, perforating the casing,
sealing the plug seat with a dissolvable ball/plug, and fracturing
the zone) typically would be repeated one or more times from the
toe of the horizontal portion of the well towards the heel. Then,
the ball and/or plug seat would dissolve (over about 1-5 days, due
to exposure to well conditions (e.g. elevated temperature, acid
and/or brine), without the need for drilling to open the wellbore).
In other words, the wellbore might be accessed downstream of the
location of the set plug seat(s) via tubing and/or wireline without
drilling the ball and/or plug seat (due to the dissolvable nature
of the ball and/or plug seat), allowing production of the well
without drilling the ball and/or plug seat.
[0046] FIGS. 4A-D illustrate such an exemplary method. In FIG. 4A,
a plug seat 410 is pumped to the desired depth on a wireline, and
is set in place using a setting tool. Typically, this initial plug
seat 410 would be set in place towards the toe 401 of the
horizontal well 402. And typically, the plug seat 410 would be set
in place by application of longitudinal force upon the wedge
ring(s) of the plug seat 410, thereby driving the slip ring of the
plug seat 410 radially outward and into contact with the
casing/wellbore 405. Once the plug seat has been set, the well zone
would be perforated above the set plug seat (as shown in FIG. 4B).
Oftentimes, a single tool string would be made-up having the plug
seat 410, a setting tool (not shown), and a perforating gun (not
shown). This would allow the plug seat 410 to be set and the well
zone to be perforated in a single trip downhole.
[0047] Once the well has been perforated (and the tool string, for
example having the setting tool and or perforating gun, has been
removed), a dissolvable ball 450 might be dropped and pumped
downhole until it is seated on the plug seat 410 (as shown in FIG.
4B). Once the well has been sealed, fracturing operations may be
performed in the desired zone above the plug seat 410 (as shown in
FIG. 4B). This process may be repeated until all desired zones have
been fractured (e.g. placing multiple plug seats, typically
proceeding from the toe 401 towards the heel 402 of the horizontal
well). FIG. 4C shows an exemplary well, in which a plurality of
plug seats have been set in place and sealed (via dissolvable
ball), and fracturing operations have occurred in a zone above each
of the plug seats. In such an exemplary method, there would be no
need to drill out the plugs (after all fracturing operations have
been completed). Rather, the plugs (e.g. the ball/plug and/or wedge
ring(s)) would disappear after a predetermined period of time
(dissolving under well conditions, as shown for example in FIG.
4D). In the embodiment of FIG. 4D, the ball and wedge ring(s) would
be formed of dissolvable material, such that after the
predetermined period of time, only the slip ring (and any
elastomeric seal on the slip ring) of each plug seat would remain
in place in the well (although in other embodiments, only the ball
might be dissolvable). In such instances, the inner diameter of the
set slip ring would be sufficiently large that it would not
interfere with production of the well (for example, allowing
passage of tubing and/or wireline devices). In other embodiments,
however, the slip ring (as well as the ball and wedge ring(s))
might be formed of dissolvable material (for example, to provide an
even larger longitudinal bore). Once the dissolvable elements have
disappeared, the operator may proceed with well start-up and
production activities.
[0048] While various embodiments in accordance with the principles
disclosed herein have been shown and described above, modifications
thereof may be made by one skilled in the art without departing
from the spirit and the teachings of the disclosure. The
embodiments described herein are representative only and are not
intended to be limiting. Many variations, combinations, and
modifications are possible and are within the scope of the
disclosure. Alternative embodiments that result from combining,
integrating, and/or omitting features of the embodiment(s) are also
within the scope of the disclosure. And logic flows for methods do
not necessarily require the particular order shown, or sequential
order, to achieve desirable results. Other steps may be provided,
or steps may be eliminated, from the described flows/methods, and
other components may be added to, or removed from, the described
devices/systems. So, other embodiments may be within the scope of
the following claims.
[0049] Accordingly, the scope of protection is not limited by the
description set out above, but is defined by the claims which
follow, that scope including all equivalents of the subject matter
of the claims. In the claims, any designation of a claim as
depending from a range of claims (for example #-##) would indicate
that the claim is a multiple dependent claim based of any claim in
the range (e.g. dependent on claim # or claim ## or any claim
therebetween). Each and every claim is incorporated as further
disclosure into the specification and the claims are embodiment(s)
of the present invention(s). Furthermore, any advantages and
features described above may relate to specific embodiments, but
shall not limit the application of such issued claims to processes
and structures accomplishing any or all of the above advantages or
having any or all of the above features.
[0050] Additionally, the section headings used herein are provided
for consistency with the suggestions under 37 C.F.R. 1.77 or to
otherwise provide organizational cues. These headings shall not
limit or characterize the invention(s) set out in any claims that
may issue from this disclosure. Specifically and by way of example,
although the headings might refer to a "Field," the claims should
not be limited by the language chosen under this heading to
describe the so-called field. Further, a description of a
technology in the "Background" is not to be construed as an
admission that certain technology is prior art to any invention(s)
in this disclosure. Neither is the "Summary" to be considered as a
limiting characterization of the invention(s) set forth in issued
claims. Furthermore, any reference in this disclosure to
"invention" in the singular should not be used to argue that there
is only a single point of novelty in this disclosure. Multiple
inventions may be set forth according to the limitations of the
multiple claims issuing from this disclosure, and such claims
accordingly define the invention(s), and their equivalents, that
are protected thereby. In all instances, the scope of the claims
shall be considered on their own merits in light of this
disclosure, but should not be constrained by the headings set forth
herein.
[0051] Use of broader terms such as comprises, includes, and having
should be understood to provide support for narrower terms such as
consisting of, consisting essentially of, and comprised
substantially of. Use of the term "optionally," "may," "might,"
"possibly," and the like with respect to any element of an
embodiment means that the element is not required, or
alternatively, the element is required, both alternatives being
within the scope of the embodiment(s). Also, references to examples
are merely provided for illustrative purposes, and are not intended
to be exclusive.
[0052] Also, techniques, systems, subsystems, and methods described
and illustrated in the various embodiments as discrete or separate
may be combined or integrated with other systems, modules,
techniques, or methods without departing from the scope of the
present disclosure. Other items shown or discussed as directly
coupled or communicating with each other may be indirectly coupled
or communicating through some interface, device, or intermediate
component, whether electrically, mechanically, or otherwise. Other
examples of changes, substitutions, and alterations are
ascertainable by one skilled in the art and could be made without
departing from the spirit and scope disclosed herein.
* * * * *