U.S. patent application number 12/799231 was filed with the patent office on 2010-10-21 for combination down hole tool.
Invention is credited to W. Lynn Frazier.
Application Number | 20100263876 12/799231 |
Document ID | / |
Family ID | 42980137 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100263876 |
Kind Code |
A1 |
Frazier; W. Lynn |
October 21, 2010 |
Combination down hole tool
Abstract
A series of down hole tools are assembled from a common
subassembly to which are added various specialty parts to make a
flow back plug, a bridge plug or a plug with a disintegratable
check valve. The subassembly may be used, as is, as a ball drop
plug. The components may be added through either end of the
subassembly without having to take the subassembly apart. The
subassembly and specialty parts may be shipped to the customer so
the end user may customize the subassembly to provide a plug
operable to provide a variety of functions.
Inventors: |
Frazier; W. Lynn; (Corpus
Christi, TX) |
Correspondence
Address: |
G. TURNER MOLLER
711 NORTH CARANCAHUA, SUITE 720
CORPUS CHRISTI
TX
78401
US
|
Family ID: |
42980137 |
Appl. No.: |
12/799231 |
Filed: |
April 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61214347 |
Apr 21, 2009 |
|
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Current U.S.
Class: |
166/378 ;
166/102; 166/118; 166/123; 166/135 |
Current CPC
Class: |
E21B 33/129 20130101;
E21B 34/14 20130101; E21B 33/134 20130101; E21B 34/063
20130101 |
Class at
Publication: |
166/378 ;
166/118; 166/135; 166/102; 166/123 |
International
Class: |
E21B 33/12 20060101
E21B033/12; E21B 23/01 20060101 E21B023/01; E21B 33/129 20060101
E21B033/129; E21B 23/00 20060101 E21B023/00; E21B 23/06 20060101
E21B023/06; E21B 34/06 20060101 E21B034/06 |
Claims
1. A down hole well tool comprising a mandrel having an upper end,
a lower end and a passage between the ends; a slips/seal section
movable on an exterior of the mandrel from a running in position to
an expanded position for sealing against a production string; a
setting assembly assisting in moving the slips/seal section from
the running in position to the expanded position, the setting
assembly including a setting device rigid with the mandrel having a
partible section adjacent an upper end of the mandrel and distant
from the lower end of the mandrel for failing at a predetermined
load to separate the setting device from the mandrel, and a setting
rod connected to the setting device so that tensioning on the
setting rod parts the setting device, expands the slips/seal
section into sealing engagement with the production string and
removes the setting rod from the mandrel, the arrangement of the
setting device and setting rod being that removal of the setting
rod from the tool unblocks the mandrel passage.
2. The down hole tool of claim 1 wherein the partible section
includes a reduced thickness section of the mandrel.
3. The down hole tool of claim 2 wherein the reduced thickness
section includes a tapered section on the mandrel acting as a seat
for a ball check.
4. The down hole tool of claim 1 wherein the mandrel passage
includes a cavity below the partible section and further comprising
a ball check assembly captivated in the cavity allowing upward flow
through the mandrel passageway and preventing downward flow
therethrough.
5. The down hole tool of claim 1 wherein the mandrel passage
provides a tapered section below the partible section acting as a
seat for a ball check.
6. The down hole tool of claim 5 further comprising a ball check
seated against the tapered section preventing downward flow into
the production string.
7. The down hole tool of claim 1 wherein the mandrel passageway
provides a cavity and further comprising an obstruction in the
cavity below the partible section preventing upward flow through
mandrel passage and preventing downward flow therethrough.
8. The down hole tool of claim 1 wherein the setting rod is a solid
member having no passage therethrough.
9. The down hole tool of claim 1 wherein the mandrel passageway
provides a cavity having threads and a threaded obstruction
connected to the cavity threads converting the down hole tool to a
bridge plug.
10. The down hole tool of claim 1 wherein the setting rod is
removably attached to the mandrel and, upon removal from the
mandrel, exposes a cavity having a check valve assembly
therein.
11. The down hole tool of claim 1 wherein the setting rod is
removably attached to the mandrel and, upon removal from the
mandrel, exposes a cavity having an obstruction therein blocking
the mandrel passage and converting the down hole tool into a bridge
plug.
12. The down hole tool of claim 1 wherein the setting rod is
removably attached to the mandrel and, upon removal from the
mandrel, exposes a cavity having a ball check converting the down
hole tool into a ball drop plug.
13. A method of distributing a combination down hole well tool
having a plurality of functions, comprising shipping to a customer
a subassembly including a mandrel having an upper end, a lower end
and a passage between the ends, a slips/seal section movable on an
exterior of the mandrel from a running in position to an expanded
position for sealing against a production string and a setting
assembly assisting in moving the slips/seal section from the
running in position to the expanded position; shipping to the
customer a container having therein specialty parts comprising a
check valve assembly for converting the subassembly into a flow
back plug and an obstruction for converting the subassembly into a
bridge plug; and after the subassembly and the container are
shipped to the customer, customizing the subassembly by opening the
container and retrieving one of the specialty parts and installing
the specialty part in the subassembly.
14. The method of claim 13 wherein the subassembly and the
container are shipped to the customer in a single package.
15. The method of claim 13 wherein the subassembly includes a
setting rod for actuating the setting assembly, the setting rod
being assembled on the subassembly when it is shipped to the
customer.
16. The method of claim 13 wherein the container includes therein a
setting rod for actuating the setting assembly, the setting rod
being assembled on the subassembly after the container is
opened.
17. The method of claim 13 wherein the container further comprises
a ball check separate from the check valve assembly.
18. The method of claim 13 wherein the container further comprises
a disintegratable check.
Description
[0001] This application is based on U.S. Provisional Application
61/214,347 filed Apr. 21, 2009priority of which is claimed.
[0002] This invention relates to a tool used in wells extending
into the earth and, more particularly, to a series of down hole
tools based on a common subassembly.
BACKGROUND OF THE INVENTION
[0003] This invention is a modification or improvement over the
devices shown in U.S. patent application Ser. No.
12/317,497filed
[0004] December 23, 2008, the disclosure of which is incorporated
herein by reference.
[0005] An important development in natural gas production in recent
decades has been the drilling of horizontal legs of hydrocarbon
wells in combination with improvements in hydraulic fracturing
techniques for stimulating production from previously
uneconomically tight formations. For some years, the fastest
growing segment of gas production has been from shales or very
silty zones that previously have not been considered economic. The
current areas of increasing activity include the Barnett Shale, the
Haynesville Shale, the Fayetteville Shale, the Marcellus Shale and
other shale or shaley formations.
[0006] There are a variety of down hole tools used in the
completion and/or production of hydrocarbon wells such as bridge
plugs, flow back plugs, ball drop plugs and the like. In the past,
these have all been tools specially designed for a single
purpose.
[0007] It is no exaggeration to say that the future of natural gas
production in the continental United States is from heretofore
uneconomically tight gas bearing formations, many of which are
shales or shaley silty zones. Accordingly, a development that
allows effective frac jobs at overall lower costs is important.
SUMMARY OF THE INVENTION
[0008] As disclosed herein, there is provided a common subassembly
that can easily be assembled with specialty parts to provide a
bridge plug, a ball drop plug, or a plug having a disintegratable
ball or plug check. In addition, the subassembly may be used,
without any specialty parts, as a flow back plug. Thus, a variety
of down hole tools or plugs may be assembled from a common
subassembly and a few specialty parts that provide the special
functions of different plugs. In one aspect, a supplier does not
have to keep so much inventory because one always seems to receive
orders for what is in short supply. Another major advantage of the
disclosed device is that a subassembly and a package containing the
specialty parts may be shipped to a supply store customer or to an
operator customer. In some embodiments, the customer may use the
shipped subassembly as a ball drop tool or may remove one end from
the tool and insert one of the specialty parts in a recess at the
end of the tool and thereby convert the subassembly to a bridge
plug or a flow back plug.
[0009] An important advantage of the combination well tool
disclosed herein is that the specialty parts may be incorporated
into the subassembly without having to take the subassembly apart
and then reassemble it. This is accomplished by adding the
specialty parts through one end and leaving the opposite end of the
subassembly intact.
[0010] The subassembly parts that are common to the down hole plugs
disclosed herein are, in some embodiments, a mandrel, the elements
of a slips/seal section, a mule shoe and a setting assembly that,
when the plug is manipulated by a conventional setting tool,
expands the slips/seal section into sealing engagement with the
inside of a production or pipe string. An important advantage of
this subassembly is that manipulating the tool to set the slips
creates a passageway through the setting assembly and, in some
embodiments, through the plug. This allows the assembly of a bridge
plug, a flow back plug, a ball drop plug or a plug having a
disintegratable valve simply by the addition of specialized
parts.
[0011] In some embodiments, the common subassembly is a mandrel,
the elements of a slips/seal section and a mule shoe. In these
embodiments, the plug is expanded by pulling on the mandrel and/or
pushing on the slips/seal section to expand the slips/seal section
in a conventional manner. In application Ser. No. 12/317,497, the
common assembly includes a separate setting device attached to the
mandrel and a setting rod threaded into the setting device. Pulling
sufficiently on the setting rod strips the threads and releases the
setting rod thereby opening a passage through the mandrel thereby
allowing separate components to be inserted into the passage to
provide a bridge plug, a flow back plug, a ball drop plug and the
like.
[0012] In some embodiments of this invention, the setting device
comprises a threaded upper end of the mandrel and the setting rod
comprises a threaded member received in the threaded upper end of
the mandrel. In these embodiments, a portion of the mandrel spaced
below the threads, i.e. distanced further from the surface of the
earth, is of reduced thickness so pulling on the setting rod first
causes the slips/seal section to expand into engagement with the
inside of a production string and then causes the mandrel to fail
thereby opening a passage, or increasing the internal passage,
through the mandrel. This common subassembly allows additional
elements to be added to create a bridge plug, a flow back plug, a
ball drop plug and the like.
[0013] An important advantage of this invention is the specialty
parts added to the common subassembly are conveniently added to one
end of the common subassembly without having to take the
subassembly apart. In some embodiments, the specialty parts may be
added to a top of the subassembly and, in other embodiments, may be
added to a bottom of the subassembly.
[0014] It is an object of this invention to provide an improved
down hole well subassembly that is easily adapted to provide
different functions.
[0015] Another object of this invention is to provide an improved
down hole subassembly where specialty parts may be added to one end
of the subassembly without having to take the subassembly
apart.
[0016] A more specific object of this invention is to provide an
improved down hole plug in which a setting rod is tensioned to set
the plug on the inside of a production or pipe string and then
pulled out of the plug.
[0017] Another object of this invention is to provide an improved
method of distributing down hole well tools.
[0018] These and other objects and advantages of this invention
will become more apparent as this description proceeds, reference
being made to the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a cross-sectional view of a subassembly which is
readily modified to act as a variety of tools and which also
comprises a ball drop plug, illustrated in a running in or extended
position;
[0020] FIG. 2 is a cross-sectional view of the ball drop plug of
FIG. 1, illustrated in a set or collapsed position;
[0021] FIG. 3 is a cross-sectional view of a flow back plug
illustrated in a running in or extended position;
[0022] FIG. 4 is an enlarged cross-sectional view of a bridge plug,
illustrated in a running in or extended position;
[0023] FIG. 5 is a schematic view of a subassembly and a container
having therein specialty parts for converting the subassembly to
one of a variety of down hole tools; and
[0024] FIG. 6 is a cross-sectional view of another common
subassembly or flow back plug.
DETAILED DESCRIPTION
[0025] The present invention relates to devices for use in
hydrocarbon wells drilled into the earth and completed using a
variety of techniques. The materials from which the tools are made
are subject to considerable variation. Some of the components are
made of metals and some are made of composite plastics. Any
components left in the well are usually made of drillable
materials. Various changes and adaptations may be made in the tools
without departing from the spirit and scope of the invention, which
is to be measured solely by the claims themselves.
[0026] Referring to FIGS. 1-2, there is illustrated a subassembly
10 which is usable, without modification, as a ball drop plug and
which may have a few components added to it to provide a flow back
plug 12 shown in FIG. 3 or a bridge plug 14 as shown in FIG. 4. The
subassembly 10, the flow back plug 12 and the bridge plug 14 may
comprise, as major components in some embodiments, mandrels 20,
slips/seal sections or assemblies 22, setting assemblies 24 and
mule shoes 26. Because it is often desired to drill out the plugs
10, 12, 14 the components left in the well are typically made of
drillable materials, such as composite plastics, aluminum, bronze,
cast iron or other drillable materials. Composite plastics are well
known in the art and are of a variety of types, such as a fabric
impregnated with a suitable resin and allowed to cure, a wound
fiberglass filament resin impregnated material, a fiber molded
injection impregnated material or the like.
[0027] The mandrel 20 may provide a central axial passage 28, a
threaded section 30 intermediate the ends of the mandrel 20, a
tapered or valve seat section 32 above the threads 30 and an upper
threaded section 34. A retaining sleeve 37 may be attached to the
upper end of the mandrel 20 in any suitable manner, as by threads,
set screws, pins or the like. The words upper and lower are
somewhat inaccurate because they refer to the position of the well
tools as if they were in a vertical position while many, if not
most, of the plugs disclosed herein will be used primarily in
horizontal wells. The words upper and lower are used for purposes
of convenience rather than the more accurate proximal and distal.
The lower end 38 of the mandrel 20 is threaded for connection to
the mule shoe 26 as will be more fully apparent hereinafter.
[0028] The slips/seal section 22 may be more-or-less conventional
and provides one or more resilient seals 40 and one or more wedge
shaped elements 42 which abut wedge shaped slips 44, 46 having
wickers or teeth. The elements 42 are conveniently pinned to the
mandrel 20 by set screws, plastic bolts or pins (not shown) so the
seals 40 and elements 42 stay in place during handling. The set
screws, plastic bolts or pins (not shown) are easily sheared during
setting of the plugs 10, 12, 14. The upper slips 44 abut a ring 48
while the lower slips 46 abut a square shoulder provided by the
mule shoe 26.
[0029] The setting assembly 24 includes a setting rod 50 connected
to the mandrel 20 and may have a lower threaded end 52 received in
the threads 34. The setting assembly 24 includes some mechanism to
separate the setting rod 50 from the mandrel 20 and unblock or open
the mandrel passage 28. This mechanism may be of any suitable type
such as such as shear pins or shear screws extending through the
mandrel 20 into the setting rod 50 or may comprise a reduced
diameter, partible or necked down section 36 of the mandrel 20.
Thus, in the vocabulary of Ser. No. 12/317,497, the threads 34 and
partible neck 36 or the shear pins/screws comprise a setting
device. Because the setting rod 50 is removed from the well, in
most embodiments it is normally not made of a drillable material
and is typically of steel. As is apparent, the setting device or
threads 34 and/or necked down section 36 may provide a passage
therethrough. The setting rod 50 may be solid, i.e. have no passage
therethrough, or may be tubular having a passage therethrough. It
will be seen that part of the necked down or partible section 36
may provide the tapered valve seat 32.
[0030] When setting the plugs 10, 12, 14 the setting tool (not
shown) pulls on the setting rod 50 and/or pushes on the load ring
48, the slips/seal section 22 expands to set the seals 40 and the
slips 44, 46 against a production or pipe string in the well. The
rod 50 may be pulled completely out of the mandrel passage 28 and
it is desirable that the rod 50 pull out of the mandrel 20 in
response to a predictable force. To this end, the material of the
mandrel 28 and the thickness of the necked down section 36 are
selected to fail at a predictable tensile force.
[0031] The mule shoe 26 comprises the lower end of the subassembly
10 and differs from the device shown in application Ser. No.
12/317,497 because the function altering components are at the top
or proximal end of the plugs 10, 12, 14 rather than at the bottom
or distal end. The mule shoe includes a body 54 having a tapered
lower end 56 and a passage 58 opening through the lower end 56. The
mule shoe 26 includes an upper end 60 abutting the bottom of the
lower slip 46 and a series of grooves 62 which allow completion
fluids to pass more readily around the mule shoe 26 at appropriate
times, for example when the plug is being pulled by a wireline
upwardly in a liquid filled well. A pump down collar 64 slips over
the lower end of the mule shoe 26 so the plug may be pumped into a
horizontal leg of a well. In some embodiments, the mule shoe 26 may
be pinned to the mandrel 20 so it won't become unthreaded.
[0032] No special components need to be added to the subassembly 10
to provide the ball drop plug. In other words, the ball drop plug
and the subassembly 10 are identical. Thus, in one mode of
operation, a ball check 66 is dropped into a production or pipe
string (not shown) after the subassembly 10 is expanded against the
production string to seat against the tapered inlet 32. Those
skilled in the art will recognize that the ball drop plug 10 can be
used in a situation where a series of zones are to be fraced. There
are a number of ways that ball drop plugs are conventionally used,
one of which is to frac a zone, run a ball drop plug 10 into the
well above the fraced zone, drop a ball 66 into the production
string and thereby isolate the lower zone so a higher zone may be
fraced. In another mode of operation, the mandrel 20 may be
lengthened above the necked down section 36 as suggested by the
break lines in FIG. 1 to provide a recess to receive the ball check
66 which may be incorporated into the subassembly 10 before it is
run into a well, as suggested by the break lines in FIG. 1. In the
alternative, the setting rod 50 may provide a cavity 67 to receive
a ball check 66 incorporated into the subassembly 10 before it is
run into a well, as shown in dotted lines in FIG. 1.
[0033] In order to assemble the flow back plug 12 from the
subassembly 10, it is necessary only to insert a ball check
assembly 68 on the threads 30. This may be accomplished by removing
the setting rod 50, if necessary, and inserting the ball check
assembly 68 into the upper end of the mandrel 20. It will be
apparent to those skilled in the art that the flow back plug 12 is
often used in situations where a series of zones are to be fraced
in a well. After a zone is fraced, the flow back plug 12 is run
into the well and expanded against a production string. The ball
check assembly 68 prevents flow through the plug 12 is a downward
direction in a vertical well but allows the fraced zone to produce
up the production string. The ball check assembly 68 comprises a
housing 70 which may include threads 72 meshing with the threads 30
on the inside of the mandrel 20 or the housing 70 may be captivated
in the mandrel 20 in any suitable manner. The housing 70 provides
O-rings 74 sealing between the housing 70 and the mandrel 20 and a
pin 76 or other restraint preventing a ball 78 from flowing
upwardly out of the plug 12.
[0034] In order to assemble the bridge plug 14, it is necessary
only to insert an obstruction 80 onto the threads 30. In some
embodiments, the obstruction 80 includes an imperforate housing 82
having one or more O-rings or other seals 84 engaging the inside of
the mandrel 20. Threads 86 may be provided for coupling with the
threads 30 of the mandrel 20 or the housing 82 may be captivated
inside the mandrel 20 in any suitable manner. It will be seen to
those skilled in the art that the bridge plug 14 prevents flow, in
either direction, through the plug 14 so the plug 14 is used in any
situation where bridge plugs are commonly used.
[0035] It will be apparent that the ball check 66 or the ball check
78 may be made of a disintegratable material so the check valve
action of these plugs is eliminated over time.
[0036] In use, the subassembly 10 and a package containing the ball
check 66, the valve assembly 68 and the obstruction 80, and the
setting rod 50 are shipped to a supply store or customer. The
subassembly 10 may be shipped with the setting rod 50 assembled or
in the package 88. Customizing the subassembly 10 may be done at
any time simply by opening the package, retrieving the desired
specialty component and/or the setting rod 50, inserting the
desired specialty component in the mandrel passage 28 and
installing setting rod 50. Thus, customizing the subassembly 10 may
be done at a supply store, at a shop of the operator or service
company, at the well location or at any other suitable time after
receipt by the customer or its representative.
[0037] The plugs 10, 12, 14 are set in a conventional manner using
a conventional setting tool (not shown) such as a Model 10, 20,
E-4, or E-5 Setting Tool available from Baker Oil Tools, Inc.,
Houston, Tex., and appropriate connector subs are attached to the
setting rod 50 of the plug being set and an annular member rides
over the upper section end of the mandrel 20 to abut the load ring
48, which is the uppermost component of the slips/seat section 22.
When this assembly has been lowered to the desired location in a
vertical well or pumped to the desired location in a horizontal
well, the setting tool is actuated to tension the rod 50 and/or
compress the load ring 48. This shears off the plastic screws 86 so
the slips 44, 46 slide toward each other on the exterior of the
mandrel 20. This forces the resilient seals 40 outwardly to seal
against the inside of the production string and expands the slips
44, 46 so the withers grip the inside of the production string and
set the plug in place. Continued pulling on the rod 50 pulls the
neck 32 of the mandrel 20 in two thereby releasing the rod 50 which
is withdrawn from the mandrel 20. This may leave the passage 28
open through its maximum internal diameter through the mandrel 20.
This allows the subassembly 10 to be used without modification as a
ball drop plug, to be configured as the flow back plug 12 of FIG. 3
or the bridge plug 14 of FIG. 4. It will be evident that FIG. 2 is
misleading in the sense that the setting assembly 50 has sheared
off from the mandrel 20 but the slips/seal section 22 is not
illustrated as being expanded. In fact, the slips/seal section 22
expands first and the setting rod 50 then shears off.
[0038] Although the function of the subassembly 10 is modified by
inserting the specialty parts into the top of the tool, the same
function can be accomplished by providing a cavity or recess
between the bottom of the mandrel 20 and the mule shoe 26 for
receiving a check valve assembly analogous to the assembly 68
and/or an obstruction analogous to the obstruction 80. In the
embodiments previously described, the mule shoe 26 may be pinned or
otherwise secured to prevent unthreading of the mule shoe 26 from
the mandrel 20. In embodiments where the specialty parts are to be
installed at the bottom of the subassembly 10, the mule shoe 26 is
simply threaded onto the mandrel 20 and any pinning of the mule
shoe 26, if desired, is accomplished after the specialty parts are
installed.
[0039] As shown in FIG. 5, it will be apparent that the subassembly
10 may be shipped to a customer along with a container 88 having
therein the ball check 66, the ball check assembly 68 and the
obstruction 80 so the plug needed may be assembled in the field by
a wire line operator. It will be apparent that the subassembly 10
and container 88 may be packaged together or shipped separately to
a customer.
[0040] Referring to FIG. 6, there is illustrated another embodiment
90 which serves as a ball drop plug or subassembly for another
family of bottom hole tools analogous to FIGS. 1-4. As illustrated,
the subassembly 90 is a combination of some components from FIGS.
1-4 and some components from application Ser. No. 12/317,497. The
subassembly 90 comprises, as major components, a mandrel 92, a
slips/seal section 94, a setting assembly 96 and a mule shoe 98.
The mandrel 92 includes an interior passage 100 having threads 102
at a suitable location to receive a ball check assembly analogous
to the ball check assembly 68 or an obstruction analogous to the
obstruction 80. The mandrel 92 includes an upper tapered ball seat
surface 104 for sealably receiving a ball check analogous to the
ball check 66. The mandrel 92 may also comprise a retaining sleeve
106 to keep the components of the slips/seal section 94 in
assembled condition.
[0041] A substantial difference between the subassemblies 10 and 90
lies in a different technique for expanding the plug. More
specifically, the setting assembly 96 comprises an elongate rod 108
which is pinned to the mandrel 92 or the mule shoe 98 by one or
more shear pins 110 extending through openings 112 into a recess
114 in the rod 108. The shear pins 110 are selected to shear or
fail at a predetermined load applied between the mandrel 92 and the
rod 108 thereby expanding the slips/seal section 94.
[0042] It will be seen that the subassembly 90 includes a setting
device comprising the connection between the mandrel 92 or mule
shoe 98 and the setting rod 108.
[0043] The subassembly 90 is set in a conventional manner, i.e. a
setting tool connects to the setting rod 96 and pushes on the upper
load ring 116 and/or pulls on the mandrel 92 thereby expanding the
slips/seal section 94 and ultimately shearing the pins 110. This
releases the rod 108 which is pulled from the mandrel 92 thereby
operating in much the same manner as the device of Ser. No.
12/317,497.
[0044] Although this down hole tool has been disclosed and
described in its preferred forms with a certain degree of
particularity, it is understood that the present disclosure of the
preferred forms is only by way of example and that numerous changes
in the details of operation and in the combination and arrangement
of parts may be resorted to without departing from the spirit and
scope of the invention as hereinafter claimed.
* * * * *