U.S. patent application number 15/674987 was filed with the patent office on 2018-01-18 for borehole plug with spiral cut slip and integrated sealing element.
This patent application is currently assigned to Baker Hughes, a GE company, LLC. The applicant listed for this patent is Baker Hughes, a GE company, LLC. Invention is credited to Yash Parekh, Barbara A. Pratt, Yingqing Xu.
Application Number | 20180016864 15/674987 |
Document ID | / |
Family ID | 60940882 |
Filed Date | 2018-01-18 |
United States Patent
Application |
20180016864 |
Kind Code |
A1 |
Parekh; Yash ; et
al. |
January 18, 2018 |
BOREHOLE PLUG WITH SPIRAL CUT SLIP AND INTEGRATED SEALING
ELEMENT
Abstract
A tapered mandrel is advanced into a spirally cut sleeve having
a corresponding taper to the mandrel. The outer surface of the
sleeve conforms to the surrounding borehole and features an
exterior recess in which a sealing element is mounted. The sleeve
diameter expands as the tapered mandrel is axially advanced. Axial
cuts in the spiral sleeve further reduce the force needed for
setting. A leading nose is provided for the uphole end of the
sealing element to allow high treatment flow rate while the sealing
element is protected from the erosive effects of high
velocities.
Inventors: |
Parekh; Yash; (Houston,
TX) ; Pratt; Barbara A.; (Pearland, TX) ; Xu;
Yingqing; (Tomball, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Baker Hughes, a GE company, LLC |
Houston |
TX |
US |
|
|
Assignee: |
Baker Hughes, a GE company,
LLC
Houston
TX
|
Family ID: |
60940882 |
Appl. No.: |
15/674987 |
Filed: |
August 11, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14694399 |
Apr 23, 2015 |
|
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15674987 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/26 20130101;
E21B 33/1291 20130101; E21B 23/01 20130101; E21B 33/1216 20130101;
E21B 33/134 20130101 |
International
Class: |
E21B 33/129 20060101
E21B033/129; E21B 23/01 20060101 E21B023/01; E21B 33/12 20060101
E21B033/12; E21B 43/26 20060101 E21B043/26 |
Claims
1. A plug assembly for borehole use, comprising: a mandrel; a slip
sleeve assembly having opposed uphole and downhole ends and
externally supporting a sealing element assembly axially spaced
from said uphole end such that said sealing assembly and said slip
sleeve assembly move in tandem relative to an external taper on
said mandrel from a run in position to wedge said sealing assembly
to the borehole in a set position.
2. The plug assembly of claim 1; wherein: said uphole end further
comprises an external taper.
3. The plug assembly of claim 2, wherein: said sealing element
assembly comprising a tapered uphole end substantially aligned with
said external taper of said uphole end of said slip sleeve
assembly.
4. The plug assembly of claim 3, wherein: said tapered uphole end
of said sealing element is coincident with said external taper of
said slip sleeve assembly.
5. The plug assembly of claim 1; wherein: said slip sleeve assembly
further comprises at least one spiral cut extending substantially
over the axial distance between said uphole and downhole ends of
said slip sleeve assembly.
6. The plug assembly of claim 1, wherein: said slip sleeve assembly
comprises an outer cylindrical surface with a plurality of wickers
and an external groove, said sealing element assembly extending
radially outside of said groove and beyond said wickers in said run
in position.
7. The plug assembly of claim 6, wherein: said sealing element
assembly is bonded, molded or 3D printed to said external
groove.
8. The plug assembly of claim 5, wherein: said slip sleeve assembly
retaining an external cylindrical shape without gaps while engaging
a borehole wall in said set position to act as an extrusion barrier
for said sealing element assembly.
9. The plug assembly of claim 1, wherein: said mandrel comprising a
seat surrounding an axial passage therethrough, said seat accepting
an object to close said passage to allow pressure on the object to
be communicated to a formation about the borehole.
10. The plug assembly of claim 9, wherein: said object and said
mandrel selectively removable without intervention.
11. The plug assembly of claim 2, wherein: said external taper
shielding said sealing element assembly from erosion and swabbing
effects from fluid under high flow rates flowing around the plug
when pushing the assembly in horizontal section of the wellbore
12. A plug assembly for borehole use, comprising: a mandrel; a slip
sleeve assembly having opposed uphole and downhole ends and
supporting a sealing element assembly such that said sealing
assembly and said slip sleeve assembly move in tandem relative to
an external taper on said mandrel from a run in position to a set
position where said sealing assembly is wedged against the
borehole; said slip sleeve assembly further comprising a spiral
cut.
13. The plug assembly of claim 12, wherein: said spiral cut
extending over a substantial length of said slip sleeve assembly
between said uphole and said downhole ends.
14. The plug assembly of claim 12, wherein: said slip sleeve
assembly retaining an external cylindrical shape without gaps while
engaging a borehole wall in said set position to act as an
extrusion barrier for said sealing element assembly.
15. The plug assembly of claim 12, wherein: said sealing element
assembly mounted externally on said slip sleeve assembly and below
said uphole end.
16. The plug assembly of claim 15, wherein: said sealing element
assembly mounted in a groove on said slip sleeve assembly.
17. The plug assembly of claim 16, wherein: said uphole end further
comprises an external taper; said sealing element assembly
comprising a tapered uphole end substantially aligned with said
external taper of said uphole end of said slip sleeve assembly.
18. The plug assembly of claim 17, wherein: said external taper
shielding said sealing element assembly from erosion and swabbing
effects from fluid under high flow rates delivered around the frac
plug assembly while pushing it in the horizontal section of the
wellbore.
19. The plug assembly of claim 12, wherein: said mandrel comprising
a seat surrounding an axial passage therethrough, said seat
accepting an object to close said passage to allow pressure on the
object to be communicated to a formation about the borehole said
object, said mandrel and at least in part said slip sleeve assembly
selectively removable without intervention.
20. The plug assembly of claim 5, wherein: said slip sleeve
assembly further comprises at least one internal or external
axially oriented score.
21. The plug assembly of claim 12, wherein: said slip sleeve
assembly further comprises at least one internal or external
axially oriented score.
22. The plug assembly of claim 1, further comprising: an internal
seal disposed between said slip sleeve and said mandrel.
23. The plug assembly of claim 12, further comprising: an internal
seal disposed between said slip sleeve and said mandrel.
24. A borehole treatment method, comprising: applying pressure
against the plug assembly of claim 1 when the plug assembly is in
said set position to direct a material to a formation about the
borehole for the treatment.
25. The method of claim 24, comprising: fracturing the formation as
said treatment.
26. A borehole treatment method, comprising: applying pressure
against the plug assembly of claim 12 when the plug assembly is in
said set position to direct a material to a formation about the
borehole for the treatment.
27. The method of claim 26, comprising: fracturing the formation as
said treatment.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S.
application Ser. No. 14/694,399 filed Apr. 23 2015.
FIELD OF THE INVENTION
[0002] The field of the invention is borehole plugs and more
particularly those having a body passage selectively closed by an
object landing on a seat surrounding the passage and integrating
functions of anchoring, sealing and prevention of sealing element
extrusion
BACKGROUND OF THE INVENTION
[0003] In downhole industries including hydrocarbon exploration and
recovery and carbon dioxide sequestration, it is often necessary or
desirable to provide for seals and anchors within a tubular body.
There have been many different types of configurations to effect
such seals and or anchors, each having its advantages and
drawbacks. Since the industries noted above experience nearly
infinite particular situations, each of which might be better
solved by one technology or another, there is a continuing need for
alternate configurations to support the vast need and to provide
enhancements in various instances.
[0004] Further, the art is always receptive to configurations that
can reduce required axial length and reduce cost of production.
Prior designs have combined a setting tool that creates relative
axial movement between a tapered body advanced relatively to a
sleeve that has an external gripping surface and an adjacent
sealing element. Slots have been provided in an axial direction to
reduce the expansion force needed for contact with the surrounding
tubular. In some embodiments the slots actually break causing the
sleeve to turn into adjacent segments pressed against a surrounding
tubular by the tapered mandrel. There are two issues with this
design, first when pumping the plug assembly (guns, adapter kit,
setting tool & plug) in the horizontal the seal has low
resistance to swab off and swabs off at low flowrates (typically 5
bpm) and second the backup ring does not have zero extrusion gap
leading to packing element extrusion under HPHT conditions (15,000
psi & 350.degree. F.). This design, in several variations, is
shown in US 2013/0186616.
[0005] The present invention addresses the shortcomings of the
design discussed above with a combination of features such as a
spiral cut slip segment that spreads radially with minimal force
but provides a barrier circumferentially with no gaps to retain the
sealing element in position. The sealing element is secured to the
slip segment short of the uphole end of the slip segment so that
flow from an uphole location around the plug initially engages a
tapered uphole end of the slip segment to deflect the fluid and
protect the sealing element from swab effects of fluid velocity.
These and other aspects of the present invention will be more
readily apparent from a review of the detailed description of the
preferred embodiment and the associated drawings while
understanding that the full scope of the invention is to be
determined from the literal and equivalent scope of the appended
claims.
SUMMARY OF THE INVENTION
[0006] A tool including a cone having a single ramp surface; a
backup disposed on the ramp surface; a pusher having one or more
slips, the pusher in contact with the backup and configured to
force the backup along the ramp surface during use of the tool.
[0007] A backup including a tubular body; a helical cut line
through the body that terminates prior to reaching an end face of
the body.
[0008] A method for fracturing a formation through which a borehole
passes including applying an occluding member to a tool as claimed
in claim 1, the tool having been installed in a borehole;
pressuring up on the borehole against the occluding member and
tool; and fracturing the formation.
[0009] In an embodiment, a tapered mandrel is advanced into a
spirally cut sleeve having a corresponding taper to the mandrel.
The outer surface of the sleeve conforms to the surrounding
borehole and features an exterior recess in which a sealing element
is mounted. The sleeve diameter expands as the tapered mandrel is
axially advanced. Axial cuts in the spiral sleeve further reduce
the force needed for setting. A leading nose is provided for the
uphole end of the sealing element to allow high flow rate while the
sealing element is protected from the swab effects of high
velocities.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0011] FIG. 1 is a cross sectional illustration of a seal and
anchor tool;
[0012] FIG. 2 is a perspective illustration of the backup
illustrated in FIG. 1;
[0013] FIG. 3 is a perspective illustration of an alternate backup
ring for the configuration of FIG. 1; and
[0014] FIG. 4 is a cross sectional illustration of an alternate
seal and anchor tool;
[0015] FIG. 5 is a section view in the run in position of the plug
with the spiral cut slip;
[0016] FIG. 6 is a perspective view of the spiral cut slip;
[0017] FIG. 7 is a section view of the spiral cut slip;
[0018] FIG. 8 is the view of FIG. 6 with axial scores to reduce
expansion force;
[0019] FIG. 9 is the view of FIG. 7 with the axial cut scores.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] A detailed description of one or more embodiments of the
disclosed apparatus and method are presented herein by way of
exemplification and not limitation with reference to the
Figures.
[0021] Referring to FIG. 1, a seal and anchor tool 10 is
illustrated in cross section that is actuated by axial compression
force. A cone 12 appears at an uphole end of the figure and
provides a single ramp surface 14 (i.e. eliminating an opposing
ramp surface at an opposite axial end of a cone structure like that
of the prior art) and in some embodiments an occluding member seat
16. The surface exhibits an angle ranging from about 2 degrees to
about 20 degrees from a longitudinal axis of the cone in some
embodiments. A seal 18 is disposed about the surface 14 and
exhibits a matching angle surface 20 at an inside thereof to the
angle of surface 14. The seal 18 provides an outside diameter
surface 22 that is cylindrical in order to reasonably closely match
an inside diameter surface 24 of a tubular in which the seal and
anchor tool 10 are to be set. Adjacent the seal 18 is a backup 26
whose purpose is to prevent or substantially reduce extrusion of
the seal 18 when the seal and anchor tool 10 experiences a pressure
differential across the seal 18. It is to be appreciated from FIG.
1 that the diameter of the seal 18 appears greater than the
diameter of the backup 26. This is intended since the seal diameter
is, in one embodiment, configured with a diameter from about 0.005
to about 0.500 inch greater than that of the backup 26 in order to
assure that the seal is fully seated and compressed to the surface
24 prior to the backup making contact with the surface 24. This
configuration ensures that sufficient compressive load on the seal
18 will be imparted before the load axially applied to the tool 10
begins to be taken up by the backup 26 and the anchor (described
below).
[0022] The anchor or slip ring pusher 28 is a full ring type that
is designed to break apart into a number of slips 30 upon axial
compression forcing the pusher 28 up the ramp surface 14. The slips
30 engage the surface 24 as will be understood by one of ordinary
skill in the art. Due to the breakage of the pusher 28, there are
potentially, circumferential gaps that could allow the seal 18 to
extrude under a sufficient pressure differential. The backup 26,
because it bridges across such gaps, operates to prevent or reduce
extrusion of the seal 18. The backup will also prevent or reduce
extrusion of the seal annularly adjacent surface 24.
[0023] Based upon FIG. 1, an artisan skilled in the art will
recognize that the convention two sided cone member is eliminated
in the configuration of the disclosed tool. Rather only one cone is
provided. This is contrary to conventional teaching and results in
a reduced axial length of the tool as well as a reduced cost of
manufacture thereof while still retaining the ability to support a
fracturing operation. Both of these features will be well received
by the art.
[0024] One embodiment of the backup 26 features a body 38
comprising single piece of material 40 composed at least in part of
polymeric materials including but not limited to,
Polytetrafluoroethylene (PTFE), Polyetheretherketone (PEEK), etc.
and metal materials including but not limited to brass, aluminum,
magnesium etc. The backup 26 is helically cut through a portion of
the material but not all of the material. Reference is made to FIG.
2 wherein the material 40 is shown with a cut line 42 that
terminates prior to reaching an end face 46 of the backup 26. It
will be appreciated in the drawing that the cut line 42 does reach
the opposite end face 48 of the backup 26 at 50 but it is to be
understood that the cut line 42 could also terminate short of end
face 48, if desired. In an embodiment, a range of uncut portion 44
over which the cut line 42 does not extend is from about 0.005'' to
about 1.00''. The uncut portion 44 functions, in this embodiment,
to provide for an initiation pressure before the backup will start
to move up the ramp 14. This will help avoid premature actuation
and give more positive feedback during intended deployment. As the
backup 26 moves up the ramp, once the uncut portion(s) 44 tear, the
diameter increases by the material 40 sliding over itself along the
cut line 42. Since the material stays circumferentially complete,
any axial openings along the slips 30 will be bridged by the backup
26. The result is zero extrusion gap and minimal actuation force
required.
[0025] Referring to FIG. 3, the backup 26 is similar but not
identical to that of FIG. 2. Rather, in FIG. 3, there are two cut
lines 52 and 54 through material 40. Each cut line 52 and 54 are
helically arranged making two helical parts 56 and 58 that are
nested with each other. At least one, and as shown both of the cut
lines 52 and 54 terminate prior to reaching an end face 60 leaving
uncut portion 62 and 64. A range of uncut portion 62 and 64 over
which the cut lines 52 and 54 do not extend is from about 0.005''
to about 1.00''. It is to be understood that more cut lines may be
added to produce more helical parts if desired. In the case of
embodiments such as FIG. 3, the uncut portions serve not only to
provide for initiation pressure before deployment as in FIG. 2 but
also to hold the helical parts together prior to deployment. In
this embodiment of backup 26 as in the previous embodiment, both
annular and axial extrusion gaps are minimized or eliminated.
[0026] It is to be appreciated that in the case of FIGS. 2 and 3,
the backup is not limited to employment in the tool described
herein (and as noted the tool does not necessarily require the
particular backup) although they do work well together. The backup
as described may be employed with any other tool requiring a backup
and the tool described herein may use other backups that provide
sufficient resistance to seal extrusion.
[0027] In another embodiment, referring to FIG. 4, a tool 70 is
illustrated that eliminates the seal 18 as described above but
maintains other components of the tool 10 of FIG. 1. It has been
determined that the backup 26 can be used alone to provide
sufficient differential pressure holding capability to support a
fracking operation without a seal 18. Therefore, for certain
operations that are cost sensitive, it may be beneficial to employ
the tool illustrated in FIG. 4.
[0028] Referring to FIG. 5, a bottom sub 70 has thread 72 for
attaching part of a setting tool that is not shown but can be an
E-4 tool sold by Baker Hughes, a GE company that is well known in
the art. Another part of the tool pushes down on mandrel 74 and
that force is schematically represented by arrow 76. A setting rod
that is not shown passes through passage 78 to releasably connect
to threads 72 when the sealing element 80 and wickers 82 of slip
sleeve assembly 84 contact the surrounding tubular or the borehole
wall that is not shown. Slip sleeve assembly 84 can be one piece
comprising portions 110, 118 and 82 or it can be multiple connected
pieces with 110 being an end regardless of there being one or more
pieces. During the setting, radial surface 86 is advanced toward
mandrel 74 until sufficient tension in the rod that is connected to
thread 72 is reached at which time the rod that is not shown shears
and the bottom sub falls in the borehole. Eventually the bottom sub
70 breaks up or disintegrates as it responds to well fluids or
other well conditions. Bottom sub 70 can be made of a controlled
electrolytic material that is known and also offered by Baker
Hughes, a GE company of Houston, Tex. USA. Other materials that
degrade or disintegrate or otherwise go away are also contemplated.
The setting rod component above the shear break during setting
comes out with the known setting tool as is well known in the
art.
[0029] The slip sleeve assembly 84 has an internal taper 88 that
conforms to the tapered outer surface 90 of frustoconically shaped
mandrel 74. Seat 92 surrounds passage 78 at top end 94 of mandrel
74. An object that is preferably a ball 96 can be pumped or
otherwise delivered to seat 92 after the setting tool that is not
shown is removed. Although shown in a single location those skilled
in the art will appreciate that a plurality of the illustrated
assemblies can be used at axially spaced locations in a borehole to
treat more than one portion of a producing interval. The plug P can
be delivered with a perforating gun and a ball dropped that are not
shown so that after the plug P is set and the perforating gun is
fired successfully a ball 96 is released to seat 92 and a treatment
into the formation against plug P can begin. It should be noted
that the wickers 82 in the run in position have a cylindrical shape
while the internal wall 88 is a taper that is preferably the same
angle as taper 90 but some angular offset is envisioned.
[0030] Referring to FIGS. 5-7 a spiral cut 98 extends preferably
from downhole end 100 to uphole end 102 but ending the cut short of
either end is also contemplated.
[0031] "Spiral cut" is a generic term meant to include complete
through the wall cuts or scores starting from the inside wall or
the outside wall or a spiral form with gaps such as a coiled spring
or no gaps, with the spiral being continuous or segmented or having
one or more than one pattern nested patterns. In general, the term
applies to a circular treatment for a generally cylindrically
shaped object that is put there to reduce force when increasing its
outer dimension when engaging a surrounding borehole surface for
support therefrom.
[0032] As mandrel 74 is axially advanced toward downhole end 100
that rests on surface 86 of bottom sub 70 the wickers 82 move
radially. Preferably adjacent coils such as 104 and 106 remain
abutting after the set position is achieved but the amount of
radial extension of each can vary somewhat to conform to
irregularities of the surrounding borehole wall or the surrounding
tubular. An external groove 108 is presented below end 102 leaving
a leading tapered segment 110 of the slip sleeve assembly 84 uphole
of the sealing element 80 shown in the groove 108 in FIG. 5.
Preferably, the sealing element 80 has a leading taper 112 that
preferably is a continuation of the taper on the segment 110
although it is envisioned that taper 112 can extend radially either
more or less than the taper of segment 110. Sealing element 80 has
a preferably cylindrical segment 114 downhole from taper 114 that
preferably extends radially beyond wickers 82 so that by the time
the wickers 82 engage the borehole wall or the surrounding tubular,
the sealing element 80 is radially compressed against the
surrounding borehole wall or tubular for a seal. The outer
dimension of the slip sleeve assembly 84 grows radially as the
mandrel 74 is axially advanced during the setting. The spiral cut
allows this radial growth to occur while keeping abutting coils
such as 104 and 106 in an abutting relationship to close of an
extrusion path in a downhole direction responsive to treatment
pressure applied from a surface location against sealing element
80. While sealing element 80 is generically represented as a single
component it can be a multi-component assembly. In the set position
the radial extension of the sealing element 80 and the wickers 82
is approximately the same particularly if the set is against a
surrounding tubular so that the slip sleeve assembly 84 functions
to anchor and to operate as an extrusion barrier at the same time.
The slip sleeve assembly 84 using recess 108 holds the sealing
element 80 in position. The leading taper 110 of the slip sleeve 84
helps to deflect fluid flowing around the seal. Thus reducing the
pressure differential around the sealing element 80. As used
herein, "taper" is used generically to refer to different shapes
that function to reduce swabbing as the plug is delivered to a
predetermined location. Thus taper encompasses a transitional
surface bigger in diameter at the seal end and smaller in diameter
at end 102. In between it can be a wavy surface or an arcuate
surface; it can be smooth or rough with surface irregularities such
as peaks or valleys or grooves, for example. Should any flow get
past the sealing element 80 it will be stopped or at least slowed
by the wickers 82 engaging the surrounding tubular or the borehole
wall. By placing the sealing element 80 in groove 108 the prospect
of fluid bypass under the sealing element 80 through the groove 108
is also minimized. Inside there is an internal groove 109 with seal
111 to engage mandrel 74 to close off an internal leak path. Thin
walled section 118 is more flexible than adjacent portions of the
slip sleeve assembly 84 and gets reaction force radially from the
set sealing element 80 to close off a leak path between the mandrel
74 and the slip sleeve assembly 84. Seal 80 can be bonded, molded
or 3-D printed into groove 118. Various components of the plug P
can be made of disintegrating materials to avoid a need for milling
out after the treatment is over. The mandrel 74 with ball 96 can be
made of disintegrating materials. In some cases the slip sleeve
assembly or parts thereof can be made of a disintegrating material
or material that otherwise goes away without well intervention of
tools. In some instances at least a part of the sealing element 80
can also disintegrate or otherwise disappear. FIGS. 8 and 9 show
axial scores 120 that can extend to downhole end 100 to make radial
expansion of the slip sleeve assembly 84 easier to accomplish with
a reduced force. One or more such scores can be used or other
weakening devices to reduce expansion force needed can be used.
Preferably such scores or undercuts do not extend to an exterior
surface where the wickers 82 are located. Scores 120 also come up
short of the groove 108 as shown in FIG. 9, Scores 120 could
optionally be on the outside as an alternative or as an addition to
those shown on the inside. It should be noted that the increase in
radial dimension of the slip sleeve assembly 84 comes with a
decrease of its axial length that also has the effect of adding an
axial compression force to the sealing element 80 although the
applied axial forces from the setting tool establish a wedging
action due to relative axial movement of the slip sleeve assembly
84 with sealing element 80 relative to mandrel 74.
[0033] The teachings of the present disclosure may be used in a
variety of well operations. These operations may involve using one
or more treatment agents to treat a formation, the fluids resident
in a formation, a wellbore, and/or equipment in the wellbore, such
as production tubing. The treatment agents may be in the form of
liquids, gases, solids, semi-solids, and mixtures thereof.
Illustrative treatment agents include, but are not limited to,
fracturing fluids, acids, steam, water, brine, anti-corrosion
agents, cement, permeability modifiers, drilling muds, emulsifiers,
demulsifiers, tracers, flow improvers etc. Illustrative well
operations include, but are not limited to, hydraulic fracturing,
stimulation, tracer injection, cleaning, acidizing, steam
injection, water flooding, cementing, etc.
[0034] It is also contemplated for any or all of the
components/tools described above that materials such as a
controlled electrolytic metallic material (Intallic.RTM.
commercially available from Baker Hughes, Houston Tex.) or other
dissolvable or disintegrable material be employed so that the
entirety or some portion of the entirety of the tools may be
removed through dissolution via natural borehole fluids or applied
fluids at an appropriate time.
[0035] The tool embodiments disclosed herein are particularly
suited to fracturing a formation through which a borehole passes
while reducing expense in production of the tool, reducing
longitudinal axial length of the installed to and optionally
reducing costs for removal of the tool. The fracturing operation
comprises: installing one of the embodiments set forth above in a
borehole; applying an occluding member on the tool; pressuring up
on the borehole against the occluding member and tool; fracturing a
formation adjacent the borehole and removing the tool from the
borehole.
[0036] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) are to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. Further, it should further be
noted that the terms "first," "second," and the like herein do not
denote any order, quantity, or importance, but rather are used to
distinguish one element from another. The modifier "about" used in
connection with a quantity is inclusive of the stated value and has
the meaning dictated by the context (e.g., it includes the degree
of error associated with measurement of the particular
quantity).
[0037] While the invention has been described with reference to an
exemplary embodiment or embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted for elements thereof without departing from the
scope of the invention. In addition, many modifications may be made
to adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the claims. Also, in
the drawings and the description, there have been disclosed
exemplary embodiments of the invention and, although specific terms
may have been employed, they are unless otherwise stated used in a
generic and descriptive sense only and not for purposes of
limitation, the scope of the invention therefore not being so
limited.
* * * * *