U.S. patent application number 16/056679 was filed with the patent office on 2020-02-13 for frac plug with sealing element compression mechanism.
The applicant listed for this patent is PetroQuip Energy Services, LLP. Invention is credited to Robert Joe Coon, Antonio B. Flores, Roddie R. Smith.
Application Number | 20200048981 16/056679 |
Document ID | / |
Family ID | 69405663 |
Filed Date | 2020-02-13 |
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United States Patent
Application |
20200048981 |
Kind Code |
A1 |
Coon; Robert Joe ; et
al. |
February 13, 2020 |
Frac Plug with Sealing Element Compression Mechanism
Abstract
A frac plug is provided. The frac plug may include a plug body,
a slip, a sealing element, and a compression ring. The plug body
may have a first end portion and a second end portion. The slip may
be circumferentially disposed about the plug body and configured to
expand and couple the frac plug to a tubular section. The sealing
element may be circumferentially disposed about the plug body and
configured to create a seal between the plug body and an inner
surface of the tubular section. The compression ring may be
circumferentially disposed about the plug body proximate to the
first end portion and abut the sealing element. The compression
ring may be configured to expand when shifted along the plug body
to compress the sealing element and retain the sealing element in a
compressed position.
Inventors: |
Coon; Robert Joe; (Missouri
City, TX) ; Smith; Roddie R.; (Katy, TX) ;
Flores; Antonio B.; (Cypress, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PetroQuip Energy Services, LLP |
Waller |
TX |
US |
|
|
Family ID: |
69405663 |
Appl. No.: |
16/056679 |
Filed: |
August 7, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 33/128 20130101;
E21B 33/1216 20130101; E21B 33/129 20130101; E21B 33/1293
20130101 |
International
Class: |
E21B 33/128 20060101
E21B033/128; E21B 33/129 20060101 E21B033/129 |
Claims
1. A frac plug, comprising: a plug body having a first end portion
and a second end portion; a slip circumferentially disposed about
the plug body, the slip configured to expand and couple the frac
plug to a tubular section; a sealing element circumferentially
disposed about the plug body and configured to create a seal
between the plug body and an inner surface of the tubular section;
and a compression ring circumferentially disposed about the plug
body proximate to the first end portion and abutting the sealing
element, the compression ring configured to expand when shifted
along the plug body to compress the sealing element and retain the
sealing element in a compressed position.
2. The frac plug of claim 1, wherein the compression ring comprises
a composite material.
3. The frac plug of claim 1, wherein the compression ring comprises
a ductile metal.
4. The frac plug of claim 1, wherein the plug body comprises: a
first sub; and a second sub threadably engaged with the first
sub.
5. The frac plug of claim 1, wherein the slip comprises: a taper on
an inner surface of the slip that extends along an axial length of
the slip between a first end portion and a second end portion; and
a left-hand thread pattern defined by an outer surface of the slip
and extending from the first end portion of the slip along a
portion of the axial length.
6. The frac plug of claim 5, wherein the slip further comprises at
least one thread defined by the outer surface of the slip and
adjacent the second axial end portion of the slip, the at least one
thread having a crest that is angled away from the left-hand thread
pattern.
7. The frac plug of claim 1, wherein the compression ring
comprises: an annular body having an inner surface; and a plurality
of beads embedded in the inner surface of the annular body and
configured to increase friction between the compression ring and
the plug body.
8. The frac plug of claim 7, wherein the inner surface of the
annular body defines a thread pattern and the plurality of beads
are embedded between threads of the thread pattern.
9. The frac plug of claim 1, wherein an inner surface of the
compression ring is tapered.
10. The frac plug of claim 1, wherein the compression ring is
configured to shift along a tapered portion of an outer surface of
the plug body.
11. A frac plug comprising: a plug body, comprising: a first sub
having a taper extending along a portion of an outer surface, and a
second sub threadably engaged with the first sub; a slip
circumferentially disposed about the plug body between the first
sub and the second sub, the slip configured to expand and couple
the frac plug to a tubular section; a sealing element
circumferentially disposed about the first sub, the sealing element
configured to create a seal between the plug body and an inner
surface of the tubular section; and a compression ring having a
tapered inner surface, the compression ring circumferentially
disposed about the first sub and abutting the sealing element, and
configured to expand when shifted along the taper of the first sub
to compress the sealing element and retain the sealing element in a
compressed position.
12. The frac plug of claim 11, wherein the compression ring
comprises a composite material.
13. The frac plug of claim 11, wherein the compression ring
comprises: an annular body having an inner surface; and a plurality
of beads embedded in the inner surface of the annular body and
configured to increase friction between the compression ring and
the first sub.
14. The frac plug of claim 13, wherein the inner surface of the
annular body defines a thread pattern and the plurality of beads
are embedded between threads of the thread pattern.
15. The frac plug of claim 11, wherein the second sub is threadably
engaged with the first sub via a lock ring.
16. The frac plug of claim 11, wherein the slip comprises: a taper
on an inner surface of the slip that extends along an axial length
of the slip between a first end portion and a second end portion;
and a left-hand thread pattern defined in an outer surface of the
slip and extending from the first end portion of the slip along a
portion of the axial length.
17. The frac plug of claim 16, wherein the slip further comprises
at least one thread defined in the outer surface of the slip and
adjacent the second axial end portion of the slip, the at least one
thread having a crest that is angled away from the left-hand thread
pattern.
18. A method for setting a frac plug within a tubular section
disposed in a wellbore, the method comprising: disposing the frac
plug on a running tool; positioning the frac plug within the
tubular section using the running tool; compressing the frac plug
with the running tool; shifting a compression ring of the frac plug
along an outer surface of the frac plug to expand the compression
ring and compress a sealing element of the frac plug to create a
seal between the frac plug and an inner surface of the tubular
section, wherein friction between the compression ring and a plug
body of the frac plug prevents movement of the compression ring
away from the sealing element; and engaging a left-hand thread
pattern defined in an outer surface of a slip of the frac plug with
the inner surface of the tubular section to retain the frac plug
within the tubular section.
19. The method of claim 18, wherein the frac plug further comprises
a first sub and a second sub, and the method further comprises
ratcheting the second sub along a threadable engagement with the
first sub to hold the frac plug in a compressed position.
20. The method of claim 19, wherein the frac plug further comprises
a back-up ring, and the method further comprises expanding the
back-up ring along a taper of the first sub such that the back-up
ring contacts the tubular section and prevent extrusion of the
sealing element.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application having Ser. No. 62/544,032, which was filed Aug.
11, 2017. The aforementioned patent application is hereby
incorporated by reference in its entirety into the present
application to the extent consistent with the present
application.
BACKGROUND
[0002] In oil and gas production, it is sometimes beneficial to
stimulate a reservoir by pumping in high pressure fluids and
particulates, such as sand. In order to do this, one or more
tubular sections of a tubular installed in the well may need to be
isolated for a period of time and re-opened so the well can be
produced.
[0003] One means of isolation is a frac plug. A frac plug is a
hollow, cylindrical plug which can be installed in the tubular to
isolate one or more sections. Current designs generally utilize a
sealing ball that is pumped into place against the plug. Seating
the sealing ball stops fluid flow through the bore of the frac
plug. In addition, a seal may be disposed between the outer
diameter of the frac plug and the tubular to prevent flow
therebetween. Thus, hydrocarbons from the reservoir cannot flow
through the bore of the frac plug and cannot divert around the
outside of the frac plug. This isolates the selected portions of
the well by preventing fluid flow from the surface to the reservoir
and vice versa.
[0004] Frac plugs are usually built around a central mandrel.
Typically, the central mandrel is then positioned in the wellbore
and held in place using upper and lower slips. Frac plugs may also
rely on a ratcheting mechanism to hold components of the frac plug
in a compressed position. However, such arrangements may prevent a
sealing element from fully compressing if the slips become fully
engaged prior to full compression of the sealing element. Further,
ratcheting mechanisms typically travel over teeth and then relax
back onto the teeth, resulting in a backlash which can also prevent
full compression of the sealing element.
[0005] What is needed, therefore, is a frac plug that can ensure
full compression of the sealing element.
SUMMARY
[0006] Embodiments of the disclosure may provide a frac plug. The
frac plug may include a plug body, a slip, a sealing element, and a
compression ring. The plug body may have a first end portion and a
second end portion. The slip may be circumferentially disposed
about the plug body and configured to expand and couple the frac
plug to a tubular section. The sealing element may be
circumferentially disposed about the plug body and configured to
create a seal between the plug body and an inner surface of the
tubular section. The compression ring may be circumferentially
disposed about the plug body proximate to the first end portion and
abut the sealing element. The compression ring may be configured to
expand when shifted along the plug body to compress the sealing
element and retain the sealing element in a compressed
position.
[0007] Embodiments of the disclosure may further provide a frac
plug. The frac plug may include a plug body, a slip, a sealing
element, and a compression ring. The plug body may include a first
sub having a taper that extends along a portion of an outer surface
and a second sub that is threadably engaged with the first sub. The
slip may be circumferentially disposed about the plug body between
the first sub and the second sub, and configured to expand and
couple the frac plug to a tubular section. The sealing element may
be circumferentially disposed about the first sub and configured to
create a seal between the plug body and an inner surface of the
tubular section. The compression ring may have a tapered inner
surface, be circumferentially disposed about the first sub, and
abut the sealing element. The compression ring may be configured to
expand when shifted along the taper of the first sub to compress
the sealing element and retain the sealing element in a compressed
position.
[0008] Embodiments of the disclosure may further provide a method
for setting a frac plug within a tubular section disposed in a
wellbore. The method may include disposing the frac plug on a
running tool. The method may also include positioning the frac plug
within the tubular section using the running tool. The method may
further include compressing the frac plug with the running tool.
The method may also include shifting a compression ring of the frac
plug along an outer surface of the frac plug to expand the
compression ring and compress a sealing element of the frac plug to
create a seal between the frac plug and an inner surface of the
tubular section, where friction between the compression ring and a
plug body of the frac plug prevents movement of the compression
ring away from the sealing element. The method may further include
engaging a left-hand thread pattern defined in an outer surface of
a slip of the frac plug with the inner surface of the tubular
section to retain the frac plug within the tubular section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present disclosure is best understood from the following
detailed description when read with the accompanying Figures. It is
emphasized that, in accordance with the standard practice in the
industry, various features are not drawn to scale. In fact, the
dimensions of the various features may be arbitrarily increased or
reduced for clarity of discussion.
[0010] FIG. 1 illustrates a cutaway view of two exemplary frac
plugs set in a tubular section disposed in a wellbore formed in a
subterranean formation, according to one or more embodiments
disclosed.
[0011] FIG. 2A illustrates a cross-sectional view of one of the
frac plugs of FIG. 1.
[0012] FIG. 2B illustrates an enlarged view of the portion of the
frac plug indicated by the detail labeled 2B of FIG. 2A.
[0013] FIG. 2C illustrates an enlarged view of the portion of the
frac plug indicated by the detail labeled 2C of FIG. 2A.
[0014] FIG. 3 illustrates a cross-sectional view of an exemplary
compression ring, according to one or more embodiments
disclosed.
[0015] FIG. 4 illustrates the frac plug of FIGS. 2A-2C being run
into the wellbore.
[0016] FIG. 5 illustrates the frac plug of FIG. 4 as the frac plug
is being set in position within the tubular section.
[0017] FIG. 6 illustrates the frac plug of FIG. 5 in the set
position.
[0018] FIG. 7 illustrates the running tool being retracted from the
frac plug of FIG. 6.
[0019] FIG. 8 illustrates the frac plug of FIG. 7 sealed with a
sealing ball.
DETAILED DESCRIPTION
[0020] It is to be understood that the following disclosure
describes several exemplary embodiments for implementing different
features, structures, or functions of the invention. Exemplary
embodiments of components, arrangements, and configurations are
described below to simplify the present disclosure; however, these
exemplary embodiments are provided merely as examples and are not
intended to limit the scope of the invention. Additionally, the
present disclosure may repeat reference numerals and/or letters in
the various exemplary embodiments and across the Figures provided
herein. This repetition is for the purpose of simplicity and
clarity and does not in itself dictate a relationship between the
various exemplary embodiments and/or configurations discussed in
the various Figures. Moreover, the formation of a first feature
over or on a second feature in the description that follows may
include embodiments in which the first and second features are
formed in direct contact, and may also include embodiments in which
additional features may be formed interposing the first and second
features, such that the first and second features may not be in
direct contact. Finally, the exemplary embodiments presented below
may be combined in any combination of ways, i.e., any element from
one exemplary embodiment may be used in any other exemplary
embodiment, without departing from the scope of the disclosure.
[0021] Additionally, certain terms are used throughout the
following description and claims to refer to particular components.
As one skilled in the art will appreciate, various entities may
refer to the same component by different names, and as such, the
naming convention for the elements described herein is not intended
to limit the scope of the invention, unless otherwise specifically
defined herein. Further, the naming convention used herein is not
intended to distinguish between components that differ in name but
not function. Additionally, in the following discussion and in the
claims, the terms "including" and "comprising" are used in an
open-ended fashion, and thus should be interpreted to mean
"including, but not limited to." All numerical values in this
disclosure may be exact or approximate values unless otherwise
specifically stated. Accordingly, various embodiments of the
disclosure may deviate from the numbers, values, and ranges
disclosed herein without departing from the intended scope.
Furthermore, as it is used in the claims or specification, the term
"or" is intended to encompass both exclusive and inclusive cases,
i.e., "A or B" is intended to be synonymous with "at least one of A
and B," unless otherwise expressly specified herein.
[0022] Unless otherwise specified, use of the terms "up," "upper,"
"upward," "uphole," or other like terms shall be construed as
generally toward the surface of the formation or the surface of a
body of water; likewise, use of "down," "lower," "downward,"
"downhole," or other like terms shall be construed as generally
away from the surface of the formation or the surface of a body of
water, regardless of the wellbore orientation. Use of any one or
more of the foregoing terms shall not be construed as denoting
positions along a perfectly vertical axis.
[0023] FIG. 1 illustrates a cutaway view of two exemplary frac
plugs 100 set in a tubular 102 disposed in a wellbore 104 formed in
a subterranean formation 106, according to one or more embodiments
disclosed. The wellbore 104 may be formed in the subterranean
formation 106 via any conventional drilling means and is utilized
for the retrieval of hydrocarbons therefrom. As illustrated, at
least a portion of the wellbore 104 is oriented in a horizontal
direction in the subterranean formation 106; however, embodiments
in which the wellbore 104 is oriented in a convention vertical
direction are contemplated herein, and the depiction of the
wellbore 104 in a horizontal or vertical direction is not to be
construed as limiting the wellbore 104 to any particular
configuration. Accordingly, in some embodiments, the wellbore 104
may extend into the subterranean formation 106 in a vertical
direction, thereby having a vertical wellbore portion, and may
deviate at any angle from the vertical wellbore portion, thereby
having a deviated or horizontal wellbore portion. Thus, the
wellbore 104 may be or include portions that may be vertical,
horizontal, deviated, and/or curved.
[0024] The wellbore 104 may be in fluid communication with the
surface via a rig (not shown) and/or other associated components
positioned on the surface around the wellbore 104. The rig may be a
drilling rig or a workover rig, and may include a derrick and a rig
floor. The frac plugs 100 may be delivered to a predetermined depth
and positioned in the wellbore 104 via the rig to perform a part of
a particular servicing operation such as, for example, isolating a
section of the tubular 102 to allow fracturing of the subterranean
formation 106.
[0025] FIG. 2A illustrates a cross-sectional view of one of the
frac plugs 100 of FIG. 1. The frac plug 100 may include a plug body
202 that includes a first sub 204 and a second sub 206. Alternative
embodiments of the frac plug 100 may instead include a plug body
202 having a single sub. The frac plug 100 may further include a
slip 208, a sealing element 210, a pump down ring 212, a back-up
ring 214, and a compression ring 216. In at least one embodiment,
the external axial end portions 218 of the frac plug 100 may
include circumferentially spaced, axial protrusions 220, or
"castellations", extending from the frac plug 100. Other
embodiments of the frac plug 100 may omit the castellations 220
from one or both of the external axial end portions 218 of the frac
plug 100. The castellated axial end portions 218 are used in
stacking multiple frac plugs 100 in a manner known in the art in
some embodiments.
[0026] As shown in the exemplary embodiment, a cap 222 may be
coupled to a main body 224 of the first sub 204. The cap 222 may be
coupled to the main body 224 using adhesives, a threaded
connection, or both. Still other mechanisms for coupling the cap
222 and the main body 224, such as bonding and mechanical
fasteners, may be used in alternative embodiments. In other
embodiments, the cap 222 may be omitted.
[0027] In one embodiment, the cap 222 may be a metal casting and
the main body 224 may be a resin and fiber composite; however other
suitable composites known in the art may be used. In some
embodiments, the main body 224 may be cast, machined, or formed
from a powdered metal. Additionally, in other embodiments, the cap
222 may be machined, formed from a powdered metal, or made of a
composite material.
[0028] The second sub 206 may include a core 226 and an outer
sleeve 228, as shown in the exemplary embodiment. The core 226 may
be bonded, threadably engaged, or coupled to the outer sleeve 228
using the methods described above. In some embodiments, the core
may be cast, machined, or formed from a powdered metal and the
outer sleeve may be made of a composite material. In another
embodiment, the second sub 206 may be a single component that is
cast, machined, formed from powdered metal, or formed from a
composite material. When assembled, the core 226 of the second sub
206 may be partially disposed within the main body 224 of the first
sub 204.
[0029] The frac plug 100 may also include a threaded lock ring 230
that couples the first sub 204 to the second sub 206. In one
embodiment, the lock ring 230 may be a C-ring type lock ring that
includes a gap. In other embodiments, the lock ring 230 may be
continuous. In a further embodiment of the frac plug 100, the first
sub 204 may be threadably engaged with the second sub 206 without
the use of a lock ring 230.
[0030] The slip 208 and back-up ring 214 may be positioned between
the first and second subs 204, 206 of the frac plug 100, with the
back-up ring 214 positioned adjacent to the first sub 204 and the
slip 208. A portion of the outer surface 232 of the first sub 204
may be tapered, as shown in FIG. 2A. The slip 208, the back-up ring
214, or both may include a tapered inner surface 234, 236 that
contacts the tapered outer surface 232 of the first sub 204.
[0031] In one embodiment, the slip 208 may be made of a powdered
metal and the back-up ring 214 may be made of brass. In another
embodiment, the slip 208 may be a composite material, cast iron, or
any other material known in the art that is suitable for a slip
208. Additionally, in one or more embodiments, the back-up ring 214
may be made of titanium or another ductile metal that will allow
the back-up ring 214 to expand without fracturing.
[0032] FIG. 2B illustrates an enlarged view of the portion of the
frac plug 100 indicated by the detail labeled 2B of FIG. 2A. As
shown in FIG. 2B, the back-up ring 214 of the frac plug 100 may
have a trapezoidal cross-section. The slip 208 may include a
left-hand thread profile 238. Each thread 240 (only one indicated)
of the left-hand thread profile 238 may include a first flank 242
(only one indicated) that is longer than a second flank 244 (only
one indicated), angling the crest 246 (only one indicated) of each
thread 240 towards the second sub 206. Additionally, a portion of
the slip 208 adjacent to the back-up ring 214 may define one or
more threads 248. Each thread 248 may include a first flank 250
that is shorter than a second flank 252, angling the crest 254 of
each thread 248 towards the first sub 204. In one embodiment, the
slip 208 may include a second thread (not shown) that has a larger
pitch, a larger pitch diameter, or both a larger pitch and a larger
pitch diameter than the other thread or threads 248 that have
crests 254 angled towards the first sub 204.
[0033] Other embodiments of the slip 208 may include threads 248
that have a pitch, a pitch diameter, or both a pitch and a pitch
diameter that are the same size, or a different thread may have a
larger pitch, a larger pitch diameter, or both a larger pitch and a
larger pitch diameter than the other thread or threads 248. In
another embodiment, the one or more threads 248 may be replaced by
teeth (not shown) having points (not shown) that angle towards the
first sub 204. Further embodiments of the slip 208 may include a
left-hand thread profile 238, one or more threads 248, or both a
left-hand thread profile 238 and one or more threads 248 that have
crests 246, 254 that are generally perpendicular to the outer
surface of the slip.
[0034] Referring now to FIG. 2C, FIG. 2C illustrates an enlarged
view of the portion of the frac plug 100 indicated by the detail
labeled 2C of FIG. 2A. As shown in FIG. 2C, the compression ring
216 may be retained by the cap 222 and, in turn, retain the sealing
element 210 in position adjacent to the main body 224. This
arrangement allows the sealing element 210 to be compressed
independently of the slip 208. In another embodiment, the cap 222
may be omitted and friction may retain the compression ring 216 on
the first sub 204. The compression ring 216 may be made of a
composite material that can expand without failure. In other
embodiments, the compression ring 216 may be a ductile metal, such
as those described above in relation to the back-up ring 214, which
can expand without failure.
[0035] The compression ring 216 may further include a tapered inner
surface 256, as shown in the exemplary embodiment. Additionally, a
portion 258 of the main body 224 may be tapered. In at least one
embodiment, the taper of the inner surface 256 of the compression
ring 216 and the portion 258 of the main body 224 may be about
2.degree.. In other embodiments, the taper may be omitted from
either the compression ring 216 or the main body 224.
[0036] FIG. 3 illustrates a cross-sectional view of an exemplary
compression ring 302, according to one or more embodiments. The
compression ring 302 in FIG. 3 is alternative to the compression
ring 216 shown in FIGS. 2A-2C, and may be used in place of
compression ring 216 in frac plug 100. Accordingly, like numerals
indicate like elements and therefore will not be described again in
detail except where material to the present embodiment.
[0037] As shown in FIG. 3, the compression ring 302 may further
include a material that is set into the inner surface 256 to
increase friction between the compression ring 302 and the main
body 224. In one embodiment, the material may be a plurality of
quartz or ceramic beads 304 (only one indicated). In other
embodiments, a coating (not shown) may be applied to the inner
surface 256 to increase the friction. In another embodiment, the
compression ring 302 may include a thread pattern 306 or grooves
(not shown) defined in the inner surface 256. In additional
embodiments, the beads 304 may be set into one or more of the
grooves or one or more threads of the thread pattern 306 to
increase the friction.
[0038] FIGS. 4-8 illustrate the installation of the frac plug 100
of FIGS. 1 and 2A-2C. Initially, the frac plug 100 is positioned
within the tubular section 402 using a running tool 404 that
extends through the frac plug 100, as shown in FIG. 4. The frac
plug 100 is retained on the running tool 404 by a shear ring 406
configured to break at a predetermined load and a cylindrical
retainer 408. The shear ring 406 may be positioned adjacent to the
second sub 206 and the cylindrical retainer 408 may be positioned
adjacent to the first sub 204. The process of positioning the frac
plug 100 within the tubular section 402 may be aided by the pump
down ring 212, which helps move the frac plug 100 into position
within the tubular section 402. Once the frac plug 100 reaches the
desired location, the running tool 404 begins to compress the frac
plug 100 by pulling the shear ring 406 towards the cylindrical
retainer 408 and pushing the cylindrical retainer 408 towards the
shear ring 406.
[0039] As shown in FIG. 5, the tapered surface 232 of the first sub
204 may radially expand the slip 208 and back-up ring 214 as the
frac plug 100 is compressed. In some embodiments, this expansion
may cause the slip 208 to fracture along longitudinal grooves (not
shown), creating a plurality of slip segments (not shown). In other
embodiments, the longitudinal grooves in the slip 208 may allow the
slip 208 to expand without fracturing or the longitudinal grooves
may be omitted. As the back-up ring 214 is made of a ductile
material, the back-up ring 214 expands without fracturing as it
moves along the tapered surface 232.
[0040] As the frac plug 100 is compressed, the one or more threads
248 of the slip 208 that are facing the first sub 204 contact the
tubular section 402. The one or more threads 248 may engage or
"bite" into the inner surface 502 of tubular section 402,
preventing further movement of the second sub 206 towards the first
sub 204. Since the frac plug 100 is still being compressed by the
running tool 404, the cylindrical retainer 408 will continue to
push the first sub 204 towards the second sub 206. This movement
allows the slip 208 and back-up ring 214 to continue to move along
the tapered surface 232 of the first sub 204. The continued
expansion of the slip 208 allows the left-hand threads 240 of the
slip 208 to engage with the inner surface 502 tubular section 402,
preventing movement of the slip 208 away from the first sub 204 and
further retaining the frac plug 100 in position.
[0041] Additionally, the cylindrical retainer 408 may shift the
compression ring 216 along the cap 222 and the main body 224 as the
frac plug 100 is compressed. The taper on the compression ring 216,
the main body 224, or both causes this movement to expand the
compression ring 216 as it travels along the cap 222 and the main
body 224. The movement of the compression ring 216 also compresses
the sealing element 210 and creates a seal between the frac plug
100 and the tubular section 402. Further, the friction between the
compression ring 216 and the main body 224 prevents movement of the
compression ring 216 away sealing element 210, maintaining the seal
between the first sub 204, the sealing element 210, and the tubular
section 402.
[0042] The interface between the lock ring 230 and second sub 206
may have a ratcheting effect, where the external threads of the
second sub 206 slide over the internal threads of the lock ring 230
in one direction, but are restricted from moving in the opposite
direction by the internal threads of the lock ring 230.
Accordingly, the ratcheting effect may prevent decompression of the
frac plug 100.
[0043] In the exemplary embodiment, the compression ring 216 and
sealing element 210 are both circumferentially disposed about the
first sub 204 and separated from the slip 208 by the main body 224.
This allows the compressive force applied by the running tool 404
to independently act on the compression ring 216 and the ratcheting
interface between the lock ring 230 and the second sub 206. This
arrangement allows the frac plug 100 to continue to compress even
if one of the interfaces reaches full compression before the other
interface, ensuring the frac plug 100 is fully set within the
tubular section 402.
[0044] As shown in FIG. 6, the slip 208 may engage with the inner
surface 502 of the tubular section 402 when the frac plug 100 is
set, securing the frac plug 100 in place. Additionally, the back-up
ring 214, having expanded into the position shown in FIG. 6,
contacts the tubular section 402 and may prevent extrusion of the
sealing element 210. Once the frac plug 100 is set in position, the
shear ring 406 breaks when the predetermined load is reached. The
running tool 404 is then tripped out of the tubular section
402.
[0045] Once the running tool 404 is removed from the frac plug 100
and tubular section 402, as shown in FIG. 7, a sealing ball 802 is
dropped down the tubular section 402. The sealing ball 802 seats
against the first sub 204, as shown in FIG. 8, sealing the bore 804
of the frac plug 100. The force of the sealing ball 802 against the
first sub 204 of the frac plug 100 may further secure the frac plug
100 in place by shifting the back-up ring 214 and slip 208 further
along the tapered surface 232 of the first sub 204.
[0046] The foregoing has outlined features of several embodiments
so that those skilled in the art may better understand the present
disclosure. Those skilled in the art should appreciate that they
may readily use the present disclosure as a basis for designing or
modifying other processes and structures for carrying out the same
purposes and/or achieving the same advantages of the embodiments
introduced herein. Those skilled in the art should also realize
that such equivalent constructions do not depart from the spirit
and scope of the present disclosure, and that they may make various
changes, substitutions, and alterations herein without departing
from the spirit and scope of the present disclosure.
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