U.S. patent application number 14/632303 was filed with the patent office on 2015-09-03 for frac plug.
This patent application is currently assigned to COMPLETION TOOL DEVELOPMENTS, LLC. The applicant listed for this patent is Completion Tool Developments, LLC. Invention is credited to Gregg W. Stout.
Application Number | 20150247375 14/632303 |
Document ID | / |
Family ID | 54006536 |
Filed Date | 2015-09-03 |
United States Patent
Application |
20150247375 |
Kind Code |
A1 |
Stout; Gregg W. |
September 3, 2015 |
Frac Plug
Abstract
A plug apparatus, also called the frac cup, includes an interior
body with conical surface, a top wedge, a slip, and seal system
that limits fluid movement around the interior body while fracking
The seal system can be of the cup type, expandable pad type,
labyrinth seal type, or other device that limits fluid flow. A
method, where a plug is conveyed into the well on electric line and
a Baker type power charge setting tool, where pump fluid acts on a
cup thereby propelling the plug to a preselected position in a
horizontal wellbore. The plug provides a barrier to applied frac
slurries in order to force the frac slurries into a formation.
After the frac, the plug allows flow past an internal ball seat
from the bottom side or the plug can be milled out using coiled
tubing methods.
Inventors: |
Stout; Gregg W.;
(Montgomery, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Completion Tool Developments, LLC |
Willis |
TX |
US |
|
|
Assignee: |
COMPLETION TOOL DEVELOPMENTS,
LLC
Willis
TX
|
Family ID: |
54006536 |
Appl. No.: |
14/632303 |
Filed: |
February 26, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61945891 |
Feb 28, 2014 |
|
|
|
Current U.S.
Class: |
166/308.1 ;
166/133; 166/135; 166/386 |
Current CPC
Class: |
E21B 33/1265
20130101 |
International
Class: |
E21B 33/129 20060101
E21B033/129; E21B 43/26 20060101 E21B043/26; E21B 43/116 20060101
E21B043/116; E21B 33/128 20060101 E21B033/128; E21B 34/06 20060101
E21B034/06 |
Claims
1. A well plug comprising: a mandrel having an exterior surface, a
cup positioned on the exterior surface of the mandrel, an
expandable seal positioned on an exterior surface of the mandrel, a
plurality of anchoring elements surrounding the mandrel; and means
for moving the plurality of anchoring elements radially outwardly
to engage an inner surface of a tubular within the well.
2. The well plug of claim 1 wherein the means for moving the
plurality of anchoring elements comprises a wedge and an inclined
surface on the mandrel.
3. The well plug of claim 2 wherein the anchoring elements are
slips.
4. The well plug of claim 2 further including a locking ring
between the mandrel and the wedge.
5. The well plug of claim 1 further including a thimble secured to
the mandrel downhole of the cup, the thimble engaging a downhole
protion of the cup.
6. The well plug of claim 5 wherein the thimble includes a thin
malleable lip that is deformed outwardly so as to support the cup
when pressure is applied from above.
7. The well plug of claim 1 wherein a central fluid passageway is
provided in the mandrel.
8. The well plug of claim 7 further including a valve member
blocking flow through the central fluid passageway.
9. The well plug as claimed in claim 1 further including means for
attaching the well plug to a setting tool.
10. A method of treating a well having a casing comprising:
providing a completion tool including a perforating gun, a setting
tool and a frac plug, the frac plug including a cup member adapted
to slideably engage an interior surface of a well casing; pumping
the completion tool into the well to a predetermined location;
setting the frac plug within the well at the predetermined
location; and perforating the well casing using the perforating gun
portion of the completion tool.
11. The method of claim 10 further including the step of removing
the completion tool absent the plug from the well using coiled
tubing, wire line or electric line.
12. The method of claim 11 further including the steps of attaching
a second frac plug to the completion tool and running in the
completion tool to a second predetermined position uphole of the
first predetermined position.
13. The method of claim 12 further including the steps of setting
the second frac plug in the well and perforating the well casing a
second time with the perforating gun.
14. The well plug of claim 1 wherein the plug is made of a millable
material.
15. The well plug of claim 1 wherein the cup expands outwardly to
form a seal on an inside of the casing when pressure is applied to
the cup.
16. The method of claim 10 further including the step of pumping a
frac fluid into the well after the casing has been perforated.
Description
[0001] This Non-Provisional application claims priority to U.S.
Provisional Application Ser. No. 61/945,891 filed on Feb. 28,
2014.
BACKGROUND OF INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to downhole tools for oil and gas
wells and similar applications and more particularly to improve
multizone frac plugs and methods.
[0004] 2. Description of Related Art
[0005] Well plugs are used to form a barrier within well tubing or
casing, to create fluid barriers, or plugs, within tubing or
casing. Plugs may be used to temporarily direct acid and frac
slurries into formations to increase flow of hydrocarbons.
[0006] Typical well plugs consist of a plug body. Radially mounted
on the body are a locking mechanism, a packing element system, and
a slip system. These plugs tend to be 2 feet or longer depending on
the plug design. The packing system is typically an elastomeric
packing element with various types of backup devices. The packing
system is typically expanded outward to contact the I.D. of the
casing by a longitudinal compression force generated by a setting
tool or hydraulic piston. This force expands the elastomer and
backups to create a seal between the plug body and casing I.D. This
same longitudinal force acts through the sealing system and acts on
the slip system. The slip system is typically an upper and lower
cone that slides under slip segments and expands the slip segments
outwardly until teeth on the O.D. of a series of slip segments
engage the I.D. of the casing. Teeth or buttons on the O.D. of the
slip segments penetrate the I.D. of the casing, to secure the plug
in the casing, so the plug will not move up or down as pressure
above or below the plug is applied. A locking system typically
secures the seal and slip systems in there outward engaged position
in order to maintain compression force in the elastomer and, in
turn, compression force on the slip system.
[0007] Disadvantages with prior art plugs can be the excessive
length of the plugs since all of the above combined systems require
length. It would advantageous to have a plug that is much shorter
in that reduced material would certainly lower material and
manufacturing costs. It would be advantageous to have a very short
plug, so if plug removal is required, milling time would be greatly
reduced. Some of the drillable frac plugs on the market are the
Halliburton "Obsidian Frac Plug", the Smith Services "D2 Bridge
Plug", the Owen Type "A" Frac Plug, the Weatherford "FracGuard",
and the BJ Services "Phython". By comparison, all of these plug
designs are very long in comparison to the current invention.
[0008] Historically packer cups have been used on various types of
downhole service tools. Typical packer cups are furnished by
companies such as Oil States Industries, Inc. and are molded from a
durable oil, gas and abrasion resistant rubber compound that
withstands wear and tear. Molded into the packer cups are metal
supports such as wires to add toughness to the cups. Specially
designed packer cups are also made by companies who specialize in
the area of downhole seals. The term service tool typically means
that the tool is run into the well on either pipe or coiled tubing,
pumping or pressure operations are performed, and then the tool is
retrieved to the surface by pulling the pipe or coiled tubing. The
present invention allows a permanent set plug that is not retrieved
with pipe, as in the case of service tools, to be run into
horizontal wellbores with the utilization of faster and more
economical wireline or electric line. Normally it is not possible
to use wireline in horizontal wells because wireline tools are
gravity assisted and in horizontal wells, gravity will not move the
tools out into the horizontal section of the well. The present
invention allows pumping of fluids against the cup to provide a
force that propels the plug, setting tool, and wireline all the way
to the toe of the horizontal well. A multiple number of plugs can
be positioned and set along the length of the horizontal wellbore
to allow a "plug and perf" approach to multizone fracking In this
invention, a single cup or series of cups, are used for both
pumping the plug to the proper location in the horizontal wellbore
and creating a fluid barrier as to force frac fluids into the
formation. The plug has a simple anchoring device used in
combination with a cup which is coupled to a Baker type electric
line setting tool, and with this combination provides an economical
method to completing wells.
[0009] The current invention utilizes a typical packer cup on a
frac plug. The advantage being is that the cup can be used to pump
the plug, setting tool, electric perforating guns if desired, and
electric line through highly deviated portions of the wellbore.
Once the plug is in position, the same packer cup also creates a
fluid barrier in the I.D. of the casing thus eliminating the need
for a more expensive expandable packing element system on the plug.
It should also be understood that the cup holds pressure from above
and does not hold pressure from below.
[0010] Applied pump pressure from the surface acts on the cup from
above thus creating the fluid barrier for fracking It should also
be understood that the cup may not create the prefect seal that is
desired with expandable type packing elements so the cup acts
primarily as a fluid diverter where very small fluids leaks may
occur past the sealing edges of the cup. In high volume fracs, the
small fluid loss around the cup is undetectable at the surface.
BRIEF SUMMARY OF THE INVENTION
[0011] This invention provides an improved plug for cased wells. A
very short and simple plug that can be pumped though horizontal
wellbores. This plug can be anchored using standard electric
wireline or with hydraulic setting tools conveyed on jointed pipe
or coiled tubing.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0012] FIG. 1 is a schematic view of the present invention in the
"running position".
[0013] FIG. 2 is a schematic view of the present invention in the
"set position".
[0014] FIG. 3 is a schematic of the present invention in the
"running position" with the setting tool attached shown inside of a
section of casing where pump fluid is acting on the plugs cup to
propel the string of tools through the horizontal well.
[0015] FIG. 4 is a schematic of the present invention with the plug
set and the setting tool released from the plug. After releasing
from the plug, perforating guns are moved to a position above the
plug. The casing is then perforated before removing the setting
tool and expended guns from the well while leaving the cup plug
permanently set in the horizontal well.
DETAILED DESCRIPTION OF THE INVENTION
[0016] With reference to FIG. 1, a schematic of the present
invention shows a 180 degree cross-section of the plug 25. A
mandrel 4 has an o-ring 6 positioned in a groove. The o-ring 6
seals on the inside of the cup 5. A Pin 9 fits into slots at the
lower end of the cup 5 to prevent spinning of the cup relative to
mandrel 4. A thimble 8 threads onto the lower end of the mandrel 4
to trap the cup 5 onto mandrel 4. The thimble 8 has a thin
malleable lip 7 that is deformable outwardly as to support the cup
5 when pressure differential is applied from above. An expandable
slip system 3 slides over mandrel 4 where the slip system has sharp
teeth that can engage and penetrate the I.D. of casing. A lock ring
2 threads onto the mandrel 4 and threads inside of the wedge 1. A
ball 10 is shown at the upper inside of the plug 25. FIG. 1 shows
the plug 25 in the running position with the slips 3 retracted.
[0017] FIG. 2 shows the plug 25 in the "set position" inside of
casing 11. A setting tool 26 (shown in FIG. 3) attaches to the plug
25 in FIG. 2. The setting tool 26 attaches to plug 25 with a shear
screw 13 and shear screw 12. The setting tool 26 holds the mandrel
4 stationary with screw 12 while pushing downward against surface
23. The downward force against surface 23 moves wedge 1 downward
(to the right side of the schematic). Lock ring 2 is threadably 16
engaged to wedge 1 and moves along with wedge 1 while ratcheting
along thread 15 on mandrel 4. Surface 17 of wedge 1 pushes on slip
3 and slip 3 travels outwardly up conical surface 24 until teeth 18
engage the inside of casing 11. The teeth 18 anchor the plug 25 to
the casing 11. The cup 5 contacts the inside of casing 11 at
location 21 to block movement of fluid downward past the cup 5.
Pressure applied from above the cup 5 forces surface 22 to act on
lip 7 outwardly to contain the elastomer of cup 5, and prevent
movement of cup elastomer over thimble 8. Ball 10 lands on seat 14
to prevent fluid from traveling through bore 20. With the plug 25
in the set position the plug prevents fluid movement past the
plug.
[0018] FIG. 3 shows a view of the plug 25 attached to setting tool
26 located inside of casing 11. An electric or wireline connection
27 is shown at the top of the schematic. The plug 25 is in the
"run-in" position with the cup 5 making contact with the inside of
the casing 11. Pump pressure applied from the surface of the well
acts on the cup 5 thus propelling the plug 25 and setting tool 26
through the horizontal wellbore.
[0019] FIG. 4 shows the plug 25 in the set position inside of
casing 11. The setting tool 26 shears off and separates from plug
25. Upward movement of the wireline 30 pulls the setting tool 26
away from plug 25 a preplanned distance away from plug 25 in order
to locate perforating guns 28 inside of casing 11 relative to the
oil bearing formation. The perforating guns 28 are detonated to
create perforations 29 in casing 11. The guns 28 and setting tool
26 are retrieved to the surface by retrieving the wireline or
electric line. The well is treated by pumping frac fluids down the
casing from the surface, through the perforations in the casing
wall, so that frac fluids cannot pass plug 25 but instead are
forced through the perforations and out into the formation in order
to stimulate the formation for improved oil or gas production. The
ball 10 can be flowed back to the surface or left in place for mill
out with the plug at a later point in time.
[0020] Although the present invention has been described with
respect to specific details, it is not intended that such details
should be regarded as limitations on the scope of the invention,
except to the extent that they are included in the accompanying
claims.
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