U.S. patent application number 16/528152 was filed with the patent office on 2020-02-06 for isolation device and assembly for a hydraulic fracturing process.
The applicant listed for this patent is PetroFrac Oil Tools. Invention is credited to Robert Coon, Roddie R. Smith.
Application Number | 20200040713 16/528152 |
Document ID | / |
Family ID | 69227511 |
Filed Date | 2020-02-06 |
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United States Patent
Application |
20200040713 |
Kind Code |
A1 |
Coon; Robert ; et
al. |
February 6, 2020 |
ISOLATION DEVICE AND ASSEMBLY FOR A HYDRAULIC FRACTURING
PROCESS
Abstract
An isolation device and assembly for isolating a production
casing in a hydraulic fracturing process includes a hemispheric or
tapered first end and a cylindrical second end. The isolation
device is constructed of a dissolvable material. The hemispheric or
tapered first end seats in a plug to effect the isolation.
Inventors: |
Coon; Robert; (Missouri
City, TX) ; Smith; Roddie R.; (Katy, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PetroFrac Oil Tools |
Waller |
TX |
US |
|
|
Family ID: |
69227511 |
Appl. No.: |
16/528152 |
Filed: |
July 31, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62713318 |
Aug 1, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/26 20130101;
E21B 43/119 20130101; E21B 33/1204 20130101; E21B 2200/08
20200501 |
International
Class: |
E21B 43/119 20060101
E21B043/119; E21B 43/26 20060101 E21B043/26 |
Claims
1. An isolation device for a hydraulic fracturing plug, comprising:
a first end that is configured to seat in the hydraulic fracturing
plug; and a second end that is cylindrical, wherein the isolation
device comprises a dissolvable material.
2. The isolation device of claim 1, wherein the isolation device is
a monolithic piece.
3. The isolation device of claim 1, wherein the isolation device is
hollow.
4. The isolation device of claim 1, wherein the first end is
hemispherical.
5. The isolation device of claim 4, wherein the first end comprises
a hemispherical wall that is defined as a portion between a
hemisphere inner radius and a hemisphere outer radius, the
hemisphere inner radius and the hemisphere outer radius defined
from a central point of origin.
6. The isolation device of claim 5, wherein the hemispherical wall
has a uniform thickness.
7. The isolation device of claim 5, wherein the hemispherical wall
has a variable thickness.
8. The isolation device of claim 1, wherein the second end is
hollow.
9. The isolation device of claim 4, wherein the first end includes
a hemisphere outer radius, and the second end comprises a length
that is greater than the hemisphere outer radius.
10. The isolation device of claim 1, wherein the isolation device
includes a length that is greater than an internal diameter of a
production casing, the production casing positioned in a wellbore
and configured to receive the hydraulic fracturing plug.
11. The isolation device of claim 1, wherein the first end is
tapered.
12. An isolation device for a hydraulic fracturing process,
comprising: a hemispheric or tapered first end; and a cylindrical
second end, wherein the isolation device is hollow and comprises a
dissolvable material.
13. The isolation device of claim 12, wherein the dissolvable
material is a polyglycolic acid.
14. The isolation device of claim 12, wherein the dissolvable
material is a magnesium aluminum alloy.
15. The isolation device of claim 12, wherein the dissolvable
material is an aluminum alloy.
16. A plug assembly for a hydraulic fracturing process, comprising:
a plug that is configured to seat inside a production casing of a
wellbore; an isolation device that is configured to isolate the
production casing below the plug, wherein the isolation device
comprises a first end and a cylindrical second end, the first end
configured to seat the isolation device in the plug, and the
isolation device constructed of a dissolvable material.
17. The plug assembly of claim 16, wherein the isolation device is
hollow.
18. The plug assembly of claim 16, wherein the isolation device
includes a length that is greater than an internal diameter of the
production casing.
19. The plug assembly of claim 16, wherein the first end is
hemispherical.
20. The plug assembly of claim 16, wherein the first end is
tapered.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application having Ser. No. 62/713,318 which was filed Aug.
1, 2018. 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] Hydraulic fracturing processes, or "fracing" as the
processes are commonly known, are well stimulation techniques that
are intended to increase the production of oil and gas. Simply
stated, fracing involves drilling a wellbore into an earthen
formation with low permeability and fracturing the earthen
formation in several areas to help release and recover hydrocarbons
from the earthen formation.
[0003] Fracing usually starts by establishing a well. A wellbore
may be drilled into an earthen formation by a drill bit connected
to a drill pipe. Once the desired depth is reached, the drill bit
and the drill pipe are removed from the wellbore, and production
casing is inserted into the full length of the wellbore. The
production casing diameter is less than the diameter of the
wellbore, which leaves an open area between the outer wall of the
production casing and the wellbore. Therefore, to secure the
wellbore and to later direct the released hydrocarbons to the
surface, cement is pumped down the production casing to the bottom
of the wellbore and forced back up and around the production casing
to fill and set the open area. A temporary wellhead is installed at
the surface, therefore establishing the well.
[0004] A "plug and perf" operation may be used to complete the
well. A plug and a perforation ("perf") gun may be sent into the
wellbore via a wireline or coiled tubing. Once a desired depth is
reached, the plug is seated within the production casing. The
perforation gun is fired above the plug, thereby perforating the
production casing and the surrounding formation. The perforation
gun is removed, and a frac ball is dropped into the perforated
casing where it is seated in a reciprocal sleeve of the plug,
thereby isolating the perforated casing from the completion below.
Once the completion below is isolated, hydraulic fluid is sent down
the production casing and into the perforations, which fractures
the earthen formation and releases hydrocarbons into the wellbore.
After treatment of the fractured area is complete, another plug
with a perforation gun may be inserted into the wellbore at a
location above the previous plug and performations in the wellbore.
The plug and perf operation may be repeated in several stages. Once
the plug and perf operation is complete, the frac balls and plugs
may be removed by drilling them out, and the hydrocarbons may be
allowed to flow through the wellbore to the surface.
[0005] The frac balls, the seats of the plugs, and/or the entire
body of the plugs may be fabricated of a dissolvable material to
expedite the plug and perf process. The dissolvable material
disintegrates in the presence of wellbore fluids, therefore
eliminating the need to drill out the frac balls and plugs. The
dissolvable frac balls and plugs reduce completion time, lower
costs and risks associated with drilling out the balls and plugs
and leave behind an unobstructed wellbore for the recovery of
hydrocarbons.
[0006] However, the frac balls that are used to isolate the
wellbore may have a larger volume of dissolvable material than the
plug, which results in a longer time for the balls and plugs to
dissolve. The longer dissolving time slows down the plug and perf
completion time. Therefore, there is a need for an improved
isolation device for a hydraulic fracturing process that reduces
completion time and avoids the costs and risks associated with
drilling out balls and plugs during completion.
SUMMARY
[0007] In one embodiment of the invention, an isolation device for
a hydraulic fracturing plug may include a first end that is
configured to seat in the hydraulic fracturing plug and a second
end that is cylindrical. The isolation device may be constructed of
a dissolvable material.
[0008] In another embodiment of the invention, an isolation device
for a hydraulic fracturing process may include a hemispheric or
tapered first end and a cylindrical second end. The isolation
device may be hollow and may be constructed of a dissolvable
material.
[0009] In another embodiment of the invention, a plug assembly for
a hydraulic fracturing process may include a plug that is
configured to seat inside a production casing of a wellbore and an
isolation device that is configured to be seated in the plug and
configured to isolate the production casing below of the plug. The
isolation device may include a first end and a cylindrical second
end, and the first end may be configured to seat the isolation
device in the plug.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] 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.
[0011] FIG. 1 is a cross-sectional view of a wellbore with a plug
and an isolation device, according to one or more embodiments
disclosed herein.
[0012] FIG. 2 is an isometric view of the isolation device,
according to one or more embodiments disclosed herein.
[0013] FIG. 3 is a cross section of a side view of an isolation
device, according to one or more embodiments disclosed herein.
[0014] FIG. 4 is a cross section of a side view of another
isolation device, according to one or more embodiments disclosed
herein.
[0015] FIG. 5 is a cross section of a side view of another
isolation device, according to one or more embodiments disclosed
herein.
DETAILED DESCRIPTION
[0016] 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.
[0017] 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.
[0018] Embodiments of the invention could be used in a variety of
oil and gas applications, which could include both vertical and
directional wells. Accordingly, position terminology such as
"above" and "below" should be interpreted relative to the tubing
string opening at the surface of the earth, where "above" is in a
position closer to the opening at the surface of the earth, and
"below" is in a position further from the opening at the surface of
the earth. The terms "upstream" and "downstream" are to be
interpreted relative to the direction of flow. Upstream is against
the flow and downstream is with the flow. Accordingly, if component
A is upstream of component B, component A is closer to the toe or
end of the well then component B. The most upstream portion of the
well is the end of farthest portion of the tubing string away from
the surface.
[0019] Embodiments of the disclosure generally provide an isolation
device that is compatible with a plug that may be used to isolate a
production casing in a hydraulic fracturing process. The isolation
device may replace a dissolvable frac ball that is dropped into a
wellbore to seat in a plug to effect the isolation. The isolation
device may include a first end that is hemispheric or a conical
frustum and a second end that is cylindrical. The hemispheric or
conical frustum first end of the isolation device may be seated in
the plug. In one embodiment, the isolation device may be hollow and
may be constructed of a dissolvable material. The isolation device
may dissolve faster than a dissolvable frac ball, which results in
a faster and more efficient hydraulic fracturing process, while
eliminating the costs and risks associated with the traditional
method of drilling out balls and plugs upon completion of a
hydraulic fracturing process.
[0020] FIG. 1 is a cross-sectional view of a wellbore 10 with a
plug 15 and an isolation device 100 for use in a hydraulic
fracturing process, according to one or more embodiments disclosed
herein. The wellbore 10, which is drilled into an earthen formation
20, may include a production casing 25 extending therethrough. The
production casing may be encased in cement 30 to set the wellbore
10.
[0021] During a plug and perf operation of a hydraulic fracturing
process, a plug 15 and one or more perforating guns (not shown) may
be run into the production casing 25 to a first depth via a
wireline or coiled tubing (not shown). The plug 15 may be set
within the production casing 25 at the first depth, and the
perforating guns may be fired to create perforations 35 in the
production casing 25 and in the earthen formation 20. The wireline
or coiled tubing with the perforating guns may be removed from the
production casing 25, and the isolation device 100 may be sent down
the production casing 25 to seat on the plug 15. When the isolation
device 100 is seated on the plug 15, the perforated production
casing 25 may be effectively isolated from the completion zone
below the plug, as taken from the surface of the earth. Hydraulic
fluids may then be pumped into the production casing 25 where the
hydraulic fluids may flow out of the perforations 35 and into the
earthen formation 20. The hydraulic fluids may fracture the earthen
formation 20 thereby releasing hydrocarbons. Once treatment of the
fractured area is complete, another plug and perf operation may be
commenced at a second depth that is positioned above the first plug
and perforated casing. As the plug and perf operation occurs, the
isolation device may dissolve with continued contact with the
wellbore fluids.
[0022] FIG. 2 is an isometric view of the isolation device 100,
according to one or more embodiments disclosed herein. The
isolation device may include a first end 105 that is hemispheric
and a second end 110 that is cylindrical. The hemispheric first end
105 and the cylindrical second end 110 may be a monolithic piece or
may be connected together by any suitable fastener or fastening
method. The hemispheric first end 105 may be seated in the plug 15
shown in FIG. 1 during a plug and perf operation. In one
embodiment, the isolation device 100 may be compatible with
existing plugs for plug and perf operations.
[0023] In one embodiment, the isolation device 100 may consist of a
dissolvable material. The dissolvable material may be a dissolvable
plastic, such as polyglycolic acid ("PGA"), a dissolvable metal,
such as magnesium aluminum alloy or aluminum alloy, any other
dissolvable material suitable for a plug and perf operation, or a
combination thereof.
[0024] FIG. 3 is a cross section of a side view of the isolation
device 100, according to one or more embodiments disclosed herein.
The hemispheric first end 105 may include a hemisphere outer radius
115, as taken from a central point of origin 125. In one
embodiment, the hemisphere outer radius 115 may be compatible to
seat with the plug 15 shown in FIG. 1, and less than one-half a
diameter 40 of the production casing 25.
[0025] In one embodiment, the isolation device 100 may be hollow.
In such embodiment, the hemispheric first end 105 may also include
a hemisphere inner radius 120, as taken from the central point of
origin 125. The hemisphere outer radius 115 may define a hemisphere
outer surface area 130 of the hemispheric first end 105 and the
hemisphere inner radius 120 may define a hemisphere inner surface
area 135 of the hemispheric first end 105. Further, the hemisphere
outer radius 115 and the hemisphere inner radius 120 may define a
wall 140 of the hemispheric first end 105 with a wall thickness
145.
[0026] In one embodiment, the hemisphere outer radius 115 and the
hemisphere inner radius 120 of the hemispheric first end 105 may be
constant, and the wall thickness 145 of the wall 140 may also be
constant or uniform. However, it is contemplated within the scope
of the invention that the hemisphere inner radius 120 may vary.
[0027] Referencing FIGS. 2 and 3 together, in one embodiment, the
hemisphere inner radius 120 of the hemispheric first end 105 may
vary as a polar angle .phi. changes relative to the point of origin
125. In one embodiment, the hemisphere inner radius 120 of the
hemispheric first end 105 may vary as an azimuth angle .theta.
changes relative to the point of origin 125. In yet another
embodiment, the hemisphere inner radius 120 of the hemispheric
first end 105 may vary as both the polar angle .phi. and the
azimuth angle .theta. changes.
[0028] Referring to FIG. 3, the cylindrical second end 110 may
include a cylinder outer radius 150 and a cylinder inner radius 155
as taken from an axis y. The cylindrical second end 110 may include
a length 160. The cylinder outer radius along the length 160 may
define the cylindrical outer surface area 165, and the cylinder
inner radius 155 along the length 160 may define the cylindrical
inner surface area 170. Further, the cylinder outer radius 150 and
the cylinder inner radius 155 may define a wall 175 of the
cylindrical second end 110 with a wall thickness 180. In one
embodiment, the cylinder outer radius 150 may be equivalent to the
hemisphere outer radius 115. In one embodiment, the wall thickness
145 of the hemispheric first end 105 may be constant and uniform.
Further, the wall thickness 145 of the hemispheric first end 105
may be substantially the same (within +/-10%) as the wall thickness
180 of the cylindrical second end 110.
[0029] In another embodiment, the cylinder inner radius 155 may
vary along the length 160 of the cylindrical second end 110.
Accordingly, as the cylinder inner radius 155 varies along the
length 160 of the cylindrical second end 110, the wall thickness
180 also varies along the length 160 of the cylindrical second end
110.
[0030] In one embodiment, the length 160 of the cylindrical second
end 110 may be determined such that the isolation device 100
remains oriented with the hemispheric first end 105 pointed
downhole towards the plug 15 when it is sent down the production
casing 25, as shown in FIG. 1. In one embodiment, the length 160
may be at least longer than the hemisphere outer radius 115. In one
embodiment, the isolation device 100 may have a device length 185
that is greater than an inner diameter 40 of the production casing
25. In one embodiment, the device length 185 may be equal to the
hemisphere outer radius 115 and the length 160 of the cylindrical
second end 110 combined.
[0031] FIG. 4 is a cross section of a side view of another
isolation device 200, according to one or more embodiments
disclosed herein. The isolation device 200 is similar to the
isolation device 100 shown in FIG. 3, except the hemispheric first
end 205 may be substantially solid and may have no inner radius.
Instead, the hemispheric first end 205 may include a hemisphere
outer radius 215, as taken from a central point of origin 225. In
one embodiment, the hemisphere outer radius 215 may be compatible
to seat with the plug 15 shown in FIG. 1, and less than one-half a
diameter 40 of the production casing
[0032] The hemisphere outer radius 215 may define a hemisphere
outer surface area 230 of the hemispheric first end 205, and a
volume 242 of the hemispheric first end 205 may further be defined
by the hemisphere outer radius 215. The cylindrical second end 210
may be substantially the same as disclosed with respect to the
isolation device 100 shown in FIG. 3. The hemispheric first end 205
may include an inner surface area 235 as defined by a cylinder
inner radius 255 as determined at an axis 190 where the cylindrical
second end 210 connects to the hemispheric first end 205. The
cylindrical second end 210 may include a cylinder outer radius
250.
[0033] FIG. 5 is a cross section of a side view of another
isolation device 300, according to one or more embodiments
disclosed herein. The isolation device 300 is similar to the
isolation device 200 shown in FIG. 4, except the first end 305 may
be tapered to form a a conical frustum as shown in FIG. 5. As
shown, the first end 305 may be solid. However, it is within the
scope of the invention that the first end 305 may be hollow like
the isolation device 100 shown in FIG. 3. It is also within the
scope of the invention that the first end 305 may be conical. The
first end 305 may be compatible to seat with the plug 15 shown in
FIG. 1.
[0034] In one embodiment, the isolation device 300 may have an area
where a cylindrical second end 310 has a hollow portion 312 and a
solid portion 314. The hollow portion 312 may be defined by a
cylinder outer radius 350 and a cylinder inner radius 355 while the
solid portion 314 may be defined by the cylinder outer radius
350.
[0035] In one embodiment, the conical frustum may be defined by a
first radius 316 at a first plane and a second radius 318 at a
second plane. The two planes may be separated by a height 322. The
outer portion between the first radius 316 and the second radius
318 may form a tapered surface 324. In one embodiment, the first
radius 316 may be the same as the cylinder outer radius 350. In one
embodiment, the second radius 318 may be the same as the cylinder
inner radius 355. However, the second radius 318 may be any radius
shorter than the first radius 316 that may seat with the plug 15
shown in FIG. 1.
[0036] The isolation devices 100, 200, and 300 shown in FIGS. 3, 4,
and 5 include a greater total surface area than a frac ball with a
radius equivalent to the hemisphere outer radius 115 and 215 or to
a radius of that between the first radius 316 and the second radius
318 of a conical frustum. Because the isolation devices 100, 200,
and 300 include a greater surface area, the isolation devices 100,
200, and 300 may dissolve faster when in contact with wellbore
fluids. Additionally, in one embodiment, the isolation devices 100,
200, and 300 may also have a total volume that is less than the
frac ball with a radius equivalent to the hemisphere outer radius
115, 215 or to a radius of that between the first radius 316 and
the second radius 318 of a conical frustum. Such embodiment of the
isolation devices 100, 200, and 300 also leads to a faster
dissolution time when the isolation devices 100, 200, 300 are in
contact with wellbore fluids. The faster dissolution time may lead
to a faster and more efficient plug and perf operation. In other
words, the surface area of a ball decreases over time thus slowing
down the dissolution volume over time. By creating an internal area
of the device, the surface area increases as it dissolves thus
increasing the dissolution volume over time.
[0037] While the isolation devices disclosed herein have described
a first end as hemispherical, it is contemplated within the scope
of the invention that the first end may be a spherical cap (not
shown). In such embodiment, the spherical cap may be compatible
with seating in the plug 15 shown in FIG. 1 to isolate the wellbore
10 from the completion below. The spherical cap may be hollow or
solid. It is further contemplated within the scope of the invention
that the hemispherical first end 105 may have a different internal
profile at the location where the hemispherical first end 105
connects to the cylindrical second end 110 (not shown).
[0038] 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.
* * * * *