Note: Descriptions are shown in the official language in which they were submitted.
CA 02406259 2002-11-04
DOWNHOLE TOOL APPARATUS WITH NON-METALLIC
COMPONENTS AND METHODS OF DRILLING THEREOF
Baekc~rc>und Of The :I~wention
1. Field Of "the Invention
This invention re:Lates to dc.ownhole tools for use
in well bores and metl~.ods of drilling such apparatus
out of well bares, anc3. more pt~r~ticularly, to such
tools having c~rillable componer~ts therein made of
non-metallic materials, such as engineering grade
plastics.
2. Description of The Prior Art
In the drilling o:r xvework:ng of oil wells, a
great variety of <iownhole tools are used. For
example, but not by way of lim__tation, it is often
desirable to seal ti:~bing or~ ot:her pipe in the casing
of the well, such as when it is desired to pump
cement or other slurry down t~.zbing and force the
slurry out into a formation. It then becomes
necessary to seal the tubing with respect to the well
casing and to prevent the fluid pressure of the
slurry from 1=_ftinc~ the tubing out of the well.
Packers and bridge pli.zgs des igm>r~ .for these general
purposes are well known iz~ the art.
When it -ws desired to remove many of these
downhole tools from a. well bore, it is frequently
simpler and less expensive to m.i Ll or drill them out
rather than to imp.:Lement a complex retrieving
aperation. In mill:inc~, a mill-ir~g cutter is used to
grind the packer or plug, for example, or at least
the outer component;> thereof, oat of the well bore.
Milling is a
CA 02406259 2002-11-04
:)
relatively slow process, but it can be used an packers or
bridge plugs having relatively hard components such as
erosion-resistant hard steel. One such packer is disclosed in
U. S. Patent No. 4,151,875 to Sullaway, assigned to the
assignee of the present invention and sold under the trademark
EZ Disposal packer. Other downhole tools in addition to
packers and bridge plugs may also be drilled out.
In drilling, a drill bit is used to cut and grind up the
components of the downhole tool to remove it from the well
bore. This is a much faster operation than milling, but
requires the tool to be made out of materials which can be
accommodated by the drill bit. Typically, soft and medium
hardness cast iron are used an the pressure bearing
components, along with some brass and aluminum items. Packers
of this type include the Halliburton EZ Drill~ and EZ Drill
SV~ squeeze packers.
The EZ Drill SV° squeeze packer, far example, includes
a lock ring housing, upper slip wedge, dower slip wedge, and
lower slip support made of soft cast iron. These components
are mounted on a mandrel made of medium hardness cast iron.
The EZ Drill~ squeeze packer is similarly constructed. The
Halliburton EZ Drills' bridge plug is also similar, except that
it does not provide for fluid flow therethrough.
All of the above-mentioned packers are disclosed in
Halliburton Services Sales and Service Catalog No. 43, pages
2561-2562, and the bridge plug is disclosed i.n the same
catalog on pages 2556-2557.
CA 02406259 2002-11-04
3
The EZ Dril1~ packer and bridge plug and the EZ Drill SV~
packer are designed for fast removal from the well bore by
either rotary or cable tool drilling methods. Many of the
components in these drillable packing devices are locked
together to prevent their spinning while being drilled, and
the harder slips are grooved' so that they will be broken up in
small pieces. Typically, standard "tri-cone" rotary drill
bits are used which are rotated at speeds of about 75 to about
120 rpm. A load of about 5,000 to about 7,000 pounds of
weight is applied to the bit for initial drilling and
increased as necessary to drill out the remainder of the
packer or bridge plug, depending upon its size. Drill collars
may be used as required for weight and bit stabilization.
Such drillable devices have worked well and provide
improved operating performance at relatively high temperatures
and pressures. The packers and plug mentioned above are
designed to withstand pressures of about 10,000 psi and
temperatures of about 425° F. after being set in the well
bore. Such pressures and temperatures require the cast iron
components previously discussed.
However, drilling out iron components requires certain
techniques. Ideally, the operator employs variations in
rotary speed and bit weight to help break up the metal parts
and reestablish bit penetration should bit penetration cease
while drilling. A phenomenon known as "bit tracking" can
occur, wherein the drill bit stays on one path and no longer
cuts into the downhole tool. When th~.s happens, it is
CA 02406259 2002-11-04
4
necessary to pick up the bit above the drilling surface and
rapidly recontact the bit with the packer or plug and apply
weight while continuing rotation. This aids in breaking up
the established bit pattern and helps to reestablish bit
penetration. If this procedure is used, there are rarely
problems. However, operators may not apply these techniques
or even recognize when bit tracking has occurred. The result
is that drilling times are greatly increased because the bit
merely wears against the surface of the downhole tool rather
than cutting into it to break it up.
While cast iron components may be necessary for the high
pressures and temperatures for which they are designed, it has
been determined that many welt's experience pressures less than
10,000 psi and temperatures less than 4~5° F. This includes
most wells cemented. In fact, in the majority of wells, the
pressure is less than about 5,000 psi, and the temperature is
less than about 2S0° F. Thus, the heavy duty metal
construction of the previous downhole tools, such as the
packers and bridge plugs described above, is not necessary for
many applications, and ia: cast iron components can be
eliminated or minimi2;edJ the potential drilling problems
resulting from bit tracking might be avoided as well.
The downhole tool of the present invention solves this
problem by providing an apparatus wherein at least some of the
components, including pressure bearing components, are made of
non-metallic materials, such as engineering grade plastics.
Such plastic component:--.~ are mu<:h mor°e eas:a.ly drilled than
cast
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iron, and new drilling methods may be employed which use
alternative drill bits such as polycrystalline diamond compact
bits, or the like, rather than standard tri-cone bits.
Summary Of The Invention
The downhole tool apparatus of the present invention
utilizes non-metallic mateYials, such as engineering grade
plastics, to reduce weighty to reduce manufacturing time and
labor, to improve performance through reducing frictional
forces of sliding surfaces, to reduce costs and to improve
drillability of the apparatus when drilling is required to
remove the apparatus from the well bore Primarily, in this
disclosure, the downhole tool is characterized by well bore
packing apparatus, but it is not intended that the invention
be limited to such packing devices. The non-metallic
components in the downhole tool apparatus also allow the use
of alternative drilJ_ing techniques v~o those previously
known.
In packing apparatus embodimen~::s of the present
invention, the apparatus may utilize the same general
geometric configuration of previously known drillable packers
and bridge plugs while replacing at least some of the metal
components with non-metallic materials which can still
withstand the pressures and temperatures exposed thereto in
many well bore applications. In other embodiments of the
present invention, the apparatus may com~~r.ise specific design
changes to accommodate the advantages of elastic materials and
also to allow for the reduced strengths thereof compared to
CA 02406259 2002-11-04
metal components.
In one embodimen of the downhole tool, the invention comprises a center
mandrel and slips means disposed on the mandrel for grippingly engaging the
well
bore when in a set position. In packing embodiments, the apparatus further
comprises a packing means disposed on the mandrc;l for sealingly engaging the
well bore when in a set position.
In accordance with a further general aspect of the invention, there is
provided a downhole tool for use in a well bore, the tool comprising a mandrel
comprised of plastic, packing means disposed on the mandrel for sealingly
engaging the well bore when in a set position, upper slip means disposed on
the
mandrel above the packing means, the upper slip means for grippingly engaging
the well bore when in a set position, and lower slip means disposed on the
mandrel
below the packing means, the lower slip means for grippingly engaging the well
bore when in a set position
The slip means may comprise a wedge engaging a plurality of slips with a
slip support on the opposite side of the slips from the wedge. Any of the
mandrel,
slips, slip wedges or slip supports may be made of the non-metallic material,
such
as plastic. Specific plastics include nylon, phenolic materials and epoxy
resins.
The phenolic materials may further include any of Fiberite'~' FM4056J,
Fiberite~~M
FM4005 or ResinoidT"' 1360. The plastic ~ompot~ents may be molded or machined.
One preferred plastic material for at least some of these components is a
glass reinforced phenolic resin having a tensile strength of about 18,000 psi
and a
compressive strength of about 40,00U psi, although the invention is not
intended to
be limited to this particular plastic or a plastic having these specif a
physical
properties. The plastic materials are preferably selected such that the
packing
apparatus can withstand well pressures less than about 10,000 psi and
temperatures
less than about 425° F. In one preferred embodiment, but not by way of
limitation,
the plastic materials of the packing apparatus are selected such that the
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7
apparatus can withstand well pressures up to about 5,000 psi
and temperatures up to about 250° F.
Most of the companents of the slip means are subjected to
substantially compressive loading when in a sealed operating
position in the well bore, although same tensile loading may
also be experienced. The center mandrel typically has tensile
loading applied thereto when setting the packer and when the
packer is in its operating position.
One new method of the invention is a well bore process
comprising the steps of positioning a downhole tool into
engagement with the wel:~ bore; prior to the step of
positioning, constructing the tool such that a component
thereof is made of a non-metallic material; and then drilling
the tool out of the well bore.. The tool may be selected from
the group consisting packers and bridge plugs, but is not
limited to these devices.
The component made of non--metallic material, may be one
of several such components. The components may be
substantially subject to compressive loading. Such components
in the tool may include lock ring housings, slips, slip wedges
and slip supports. Same components, such as center mandrels
of such tools may be substantially subjected to tensile
loading.
In another embodiment, the step of drilling is carried
out using a polycrystalline diamond compact bit. Regardless
of the type of drill. bit used, the ~arocess may further
comprise the step of drilling using ~ drill bit without
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8
substantially varying the weight applied to the drill bit.
In another method of the invention, a well bore process
comprises the steps of positioning and setting a packing
device in the well bore, a portion of the device being made of
engineering grade plastic; contacting the device with well
fluids; and drilling out the device using a drill bit having
no moving parts such as a polycrystalline diamond compact bit.
This or a similar drill bit might have been previously used in
drilling the well bore itself, so the process may be said to
further comprise the step of , prior to the step of positioning
and setting the packer, drilling at least a portion of the
well bore using a drill bit such as a polycrystalline diamond
compact bit.
In one preferred embodiment, the step of contacting the
packer is at a pressure of less than about 5, 000 psi and a
temperature of less than about 2~0~~ F, although higher
pressures and temperatures may also be encountered.
It is an important object of the invention to provide a
downhole tool apparatus utilizing components made of non-
metallic materials and methods of drilling thereof.
It is another object of the invention to provide a well
bore packing apparatus using components made of engineering
grade plastic.
An additional object of the invention is to provide a
packing apparatus having a valve housing disposed
substantially below a l~~wer end of a center mandrel and having
a valve in the valve housing belo~the lower end of the center
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9
mandrel.
It is a further object of the invention to provide a
packing apparatus which may be drilled by alternate methods to
those using standard rotary drill bits.
Additional objects and advantages of the invention will
become apparent as the following detailed description of the
preferred embodiments is read in conjunction with the drawings
which illustrate such preferred embodiments.
Brief Description Of The Drawinas
FIG. 1 generally illustrates the downhole tool of the
present invention positioned in a well bore with a drill bit
disposed thereabove.
FIG. 2 illustrates a cross section of one embodiment of
a drillable packer made in accordance with the invention.
FIGS. 3A and 38 show a cross section of a second
embodiment of a drillable packer.
FIGS. 4A and 4B show a third drillable packer embodiment.
FIGS. 5A and 5B illustrate a fourth embodiment of a
drillable packer.
FIGS. 6A and 6B show a fifth drillafPle packer embodiment
with a poppet valve therein.
FIG. 7 shows a gross section of one embodiment of a
drillable bridge plug made in accordance with the present
invention.
FIG. 8 illustrates a second embodiment of a drillable
bridge plug.
CA 02406259 2002-11-04
Description Of The Preferred Embodiment
Referring now to the drawings, and more particularly to
FIG. 1, the downhole tool apparatus of the present invention
is shown and generally designated by the numeral 10.
Apparatus 10, which may include, but is not limited to,
packers, bridge plugs, or~~similar devices, is shown in an
operating position in a well bore 12. Apparatus 10 can be set
in this position by any manner known in the art such as
setting on a tubing string or wire line. A drill bit 14
connected to the end of a tool or tubing string 16 is shown
above apparatus 10 in a position to commence the drilling out
of apparatus 10 from well bore 12. Methods of drilling will
be further discussed herein.
First Packer Embodiment
Referring now to FIG. 2, the details of a first squeeze
packer embodiment 20 of apparatus 10 wi.l.l be described. The
size and configuration of packer 20 is substantially the same
as the previously mentioned prior art ~'Z Driil SV~ squeeze
packer. Packer 20 defines a generally central opening 21
therein.
Packer 20 comprises a center mandrel 22 on which most of
the other components are mounted. F~ lock ring housing 24 is
disposed around an upper end of mandrel 22 and generally
encloses a lock ring 26.
Disposed below lack ring housing 24 and pivotally
connected thereto are a plurality of upper slips 28 initially
held in place by a retaining band 30. A generally conical
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11
upper slip wedge is disposed around nnandrel 22 adjacent to
upper slips 30. Upper slip wedge 32 is held in place on
mandrel 22 by a wedge retaining ring 34 and a plurality of
screws 36.
Adjacent to the lower end of upper slip wedge 32 is an
upper back-up ring 37 and arr'upper packer shoe 38 connected to
the upper slip wedge by a pin 39. Below upper packer shoe 38
are a pair of end packer elements 40 separated by center
packer element 42. A lower packer shoe 44 and lower back-up
ring 45 are disposed adjacent to the lowermost end packer
element 40.
A generally conical lower slip wedge 46 is positioned
around mandrel 22 adjacent to lower packer shoe 44, and a pin
48 connects the lower packer shoe to the lower slip wedge.
Lower slip wedge 46 is initially attached to mandrel 22
by a plurality of screws 50 and a wedge retaining ring 52 in
a manner similar to that for upper. slip wedge 32. A plurality
of lower slips 54 are disposed adjacent tra lower slip wedge 46
and are initially held in place by a reta:~.ning band 56. Lower
slips 54 are pivotally connected to the upper end of a lower
slip support 58. Mandrel 22 is attached t.o lower slip support
58 at threaded connection 6i7.
Disposed in mandrel 22 at the upper end thereof is a
tension sleeve 62 below which is an internal seal 64. Tension
sleeve 62 is adapted for connection with a setting tool (not
shown) of a kind known in the art.
A collet-latch sl,;ding valve 66 is :~lidably disposed in
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12
central opening 21 at the lower end of mandrel 22 adjacent to
fluid ports 68 in the mandrel. Fluid ports 68 in mandrel 22
are in communication with f luid ports 7o in lower slip housing
58. The lower end of lower slip support 58 is closed below
ports 70.
Sliding valve 66 defir~s a plurality of valve ports 72 ~~'
which can be aligned with fluid ports 68 in mandrel 22 when
sliding valve 66 is in an open position. Thus, fluid can flow
through central opening 21.
On the upper end of sliding valve 66 are a plurality of
collet fingers 67 which are adapted for latching and
unlatching with a valve actuation tool knot shown) of a kind
known in the art. This actuation tool is used to open and
close sliding valve 66 as further discussed herein. As
illustrated in FIG. 2, sliding valve 66 is in a closed
position wherein fluid parts 68 are sealed by upper and lower
valve seals 74 and 76.
In prior art dril.l.able packers and bridge plugs of this
type, mandrel 22 is made of a medium hardness cast iron, and
lock ring housing 24, upper slip wedge 32, lower slip wedge 46
and lower slip support 58 are made of soft cast iron for
drillability. Most: ~~f the other components are made of
aluminum, brass or rubber which, of course, are relatively
easy to drill. Prior art upper and lower slips 28 and 54 are
made of hard cast ircn, but are grooved so that they will
easily be broken up in small. pa.eces when contacted by the
drill bit during a drilling operation.
CA 02406259 2002-11-04
13
As previously described, the soft east iron construction
of prior art lock ring housings, upper and lower slip wedges,
and lower slip supports are adapted for relatively high
pressure and temperature conditions, while a majority of well
applications do not require a design for such conditions.
Thus, the apparatus of the present invention, which is
generally designed for pressures lower than 10,000 psi and
temperatures lower than 425° f., utilizes engineering grade
plastics for at least .some of the components. For example, the
apparatus may be designed for pressures up to about 5,000 psi
and temperatures up to about 250° F., a:~though the invention
is not intended to be limited to these particular conditions.
In first packer embodiment 20, at least some of the
previously soft cast iron components of the slip means, such
as lock ring housing 24, upper and lower slip wedges 32 and 46
and lower slip support 58 are made of engineering grade
plastics. In particular, upper and lower slip wedges 32 and
46 are subjected to substantially compressive loading. Since
engineering grade plastics exhibit good strength in
compression, they make excellent choices for use in components
subjected to compressive loading. Lower- slip support 58 is
also subjected to substantially compressive loading and can be
made of engineering grade plastic when packer 20 is subjected
to relative law pressures and temperatures.
Lock ring housing 24 is mostly in compression, but does
exhibit some tensile loading. However, in most situations,
this tensile loading is minimal, and look ring housing 24 may
CA 02406259 2002-11-04
14
also be made of an engineering grade; plastic of substantially the same type
as
upper and lower slips wedges 32 and 4(i anti also lower slips housing 58.
Upper and lower slips 28 and 54 may also be of plastic in some applications.
Hardened inserts for gripping well bore 12 when packer 20 is set may be
required
as part of the plastic slips. Such construction is discussed in more detail
herein for
other embodiments of the invention.
Lock ring housing 24, upper slip wedge 32, lower slip wedge 46, and lower
slip housing 58 comprise approximately 75~%~ of the cast iron of the prior art
squeeze packers. Thus, replacing these components with similar components made
of engineering grade plastics will enhance the drillability of packer 20 and
reduce
the time and cost required therefor.
Mandrel 22 is subjected to tensile loading during setting and operation, and
many plastics will not be acceptable materials therefore. However, some
engineering plastics exhibit good tensile load~Tlg characteristics, so that
construction of mandrel 22 from such plastics is possible. Reinforcements may
be
provided in the plastic resin as necessary.
Example
A first embodiment packer 20 was constructed in which upper slip wedge
32 and lower slip wedge 46 were constructed by molding the parts to size from
a
phenolic resin plastic with glass reinforcement. The specific material used
was
FiberiteT"' 4056) manufactured by Fiberite Corporation of Winona,
CA 02406259 2002-11-04
Minnesota. This material is classified by the manufacturer as
a two stage phenolic with glass reinforcement. It has a
tensile strength of 18,000 psi and a compressive strength of
40,000 psi.
The test packer 20 held to 8,500 psi without failure to
wedges 32 and 46, more than sufficient for most well bore °w
conditions.
Second Packer Embodiment
Referring now to FIGS. 3A and 3B, the details of a second
squeeze packer embodiment 100 of packing apparatus 10 are
shown. While first embodiment 20 incorporates the same
configuration and general components as prior art packers made
of metal, second packer embodiment 100 and the other
embodiments described herein comprise specific design features
to accommodate the benefits and problems of using non-metallic
components, such as plastic.
Packer 100 comprises a center mandrel 102 on which most
of the other components are mounted. Mandrel 102 may be
described as a thick cross-sectional mandrel having a
relatively thicker wall thickness than typical packer
mandrels, including center mandrel 22 of first embodiment 20.
A thick cross-sectional mandrel. may be r,~enerally defined as
one in which the central opening therethrough has a diameter
less than about half of the outside diameter of the mandrel.
That is, mandrel central opening 104 in central mandrel 102
has a diameter less than about half the outside of center
mandrel 102. It is contemplated that. a thick cross-sectional
CA 02406259 2002-11-04
16
mandrel will be required if it is constructed from a material
having relatively low physical properties. In particular,
such materials may include phenolics and similar plastic
materials.
An upper support 106 is attached to the upper end of
center mandrel 102 at trrreaded connection 108. In an
alternate embodiment, center mandrel 102 and upper support 106
are integrally formed and there is no threaded connection 108.
A spacer ring or upper slip support 110 is disposed on the
outside of mandrel 102 just below upper support 106. Spacer
ring 110 is initially attached to center mandrel 102 by at
least one shear pin 112. A downwardly and inwardly tapered
shoulder 114 is defined on the lower side of spacer ring 110.
Disposed below spacer ring 110 are a plurality of upper
slips 116. A downwardly and inwardly sloping shoulder 118
forms the upper end of each slip i16. The taper of each
shoulder 118 conforms to the taper of shoulder 114 on spacer
ring 110, and slips 116 are adapted for sliding engagement
with shoulder 114, as will be further described herein.
An upwardly and inwardly facing taper 12o is defined in
the lower end of each slip 116. Each taper 120 generally
faces the outside of center mandrel 102.
A plurality of hardened inserts or teeth 122 preferably
are molded into upper slips 116. In the embodiment shown in
FIG. 3A, inserts 122 have a generally square cross section and
are positioned at an angle so that a radially outer edge I24
protrudes from the corresponding upper slip 116. Outer edge
CA 02406259 2002-11-04
17
124 is adapted for grippingly engaging well bore 12 when
packer 100 is set. It is not intended that inserts 322 be of
square cross section and have a distinct outer edge 124.
Different shapes of inserts may also be used. Inserts 122 can
be made of any suitable hardened material.
An upper slip wedge 126 is disposed adjacent to upper
slips 116 and engages taper 120 therein. Upper slip wedge 126
is initially attached to center mandrel 102 by one or more
shear pins 128.
Below upper slip wedge 126 are upper back-up ring 37,
upper packer shoe 38~ end packer elements 40 separated by
center packer element 42, lower packer shoe 44 and lower back-
up ring 45 which are substantially the same as the
corresponding components in first embodiment packer 20.
Accordingly, the same reference numerals are used.
Below lower back-up ring 45 is a lower slip wedge 130
which is initially attached to center mandrel 102 by a shear
pin 132. Preferably, lower slip wedge 130 is identical to
upper slip wedge 126 except that it i.s positioned in the
opposite direction.
Lower slip wedge :L38 is in engagement with an inner taper
I34 in a plurality of lower slips 236. Lower slips 136 have
inserts or teeth 138 molded therein, and preferably, lower
slips 136 are substantially identical to upper slips 126.
Each lower slip 136 has a downwardly facing shoulder
which tapers upwardly and inwardly. Shoulders 136 are adapted
for engagement with a corresponding shoulder 142 defining the
CA 02406259 2002-11-04
~$
upper end of a valve housing 144. Shoulder 142 also tapers
upwardly and inwardly. Thus, valve housing 144 may also be
considered a lower slip support 144.
Referring now also t,o FIG. 3B, valve housing 146 is
attached to the lower end of center mandrel 102 at threaded
connection 146. A sealing m?eans, such as O-ring 148, provides
sealing engagement between valve hauling 144 and center
mandrel 102.
Below the lower end of center mandrel 102, valve housing
104 defines a longitudinal opening 150 therein having a
longitudinal rib 152 in the lower end thereof. At the upper
end of opening 150 is an annular recess 1.54.
Below opening 150, valve housing 244 defines a housing
central opening including a bore 156 therein having a closed
lower end 158. A plurality of transverse ports 160 are
defined through valve housing 144 and intersect bore 156. The
wall thickness of valve housing 144 is thick enough to
accommodate a pair of annular seal grooves 162 defined in bore
156 on opposite sides of ports 160.
Slidably disposed in valve housiz~~g 144 below center
mandrel 102 is a sliding valve 164. SLie~ing valve 164 is the
same as, or substantially similar to, sliding valve 66 in
first embodiment packer 20. At the upper end of sliding valve
164 are a plurality of upwardly extending collet fingers 166
which initially engage recess 154 in valve housing 144.
Sliding valve 164 is shown in an uppermost, closed position in
FIG. 3B. It will be seen that the lower end of center mandrel
CA 02406259 2002-11-04
19
102 prevents further upward movement of sliding valve 164.
Sliding valve 164 defines a valve central opening 168
therethrough which is in communication with central opening
104 in center mandrel 102. A chamfered shoulder 170 is
located at the upper end of valve central opening 168.
Sliding valve 164 defines a plurality of substantially
transverse ports 172 therethrough which intersect valve
central opening 168. As will be further discussed herein,
ports 172 are adapted for alignment with ports 160 in valve
housing 144 when sliding valve 164 is in a downward, open
position thereof. Ri.b 152 fits between a pair of collet
fingers 166 so that sliding valve 164 cannot rotate within
valve housing 144, thus insuring proper alignment of ports 172
and 160. Rib 152 thus provides an alignment means.
A sealing means, :such as O-ring 174, is disposed in each
seal groove 162 and provides sealing engagement between
sliding valve 164 and valve housing 144. It will thus be seen
that when sliding valve 164 is moved downwardly to its open
position, O-rings 174 seal on opposite sides of ports 172 in
the sliding valve.
Referring again t:o FIS. ~A, a tension sleeve 174 is
disposed in center mandrel 102 and attached thereto to
threaded connection 176. Tension sleeve 174 has a threaded
portion 178 which extends from center mandrel 102 and is
adapted for connection to a standard setting tool (not shown)
of a kind known in the art.
Below tension sleeve 174 is an internal seal 180 similar
CA 02406259 2002-11-04
2O
to internal seal 64 in first embodiment. 20.
Third Packer Embodiment
Referring now to FIGS. 4A and 4B, a third squeeze packer
embodiment of the present invention ishown and generally
designated by the numeral 200. It will be clear to those
skilled in the art that third embodiment 200 is similar to
second packer embodiment 100 but has a couple of significant
differences.
Packer 200 comprises a center mandrel 202. Unlike center
mandrel 102 in second embodiment 100, center mandrel 202 is a
thin cross-sectional mandrel. That is, it may be said that
center mandrel 102 has a mandrel central opening 204 with a
diameter greater than about half of the=. outside diameter of
center mandrel 202. It is contemplaf:ed that thin cross-
sectional mandrels, such as center mandrel 202, may be made of
materials having relatively higher physical properties, such
as epoxy resins.
The external components of third packer embodiment 200
which fit on the outside of center mandrel 202 are
substantially identical to the outer womponents on second
embodiment 100, and therefore the same reference numerals are
shown in FIG. 4A. In a manner similar to second embodiment
packer 100, center mandrel 202 and upper support 106 may be
integrally formed so that there is no threaded connection 108.
The lower end of center mandrel 202 is attached to a
valve housing 206 at threaded connectio~a 208. on the upper
end of valve housing 20E is an upward~.y and inwardly tapered
CA 02406259 2002-11-04
21
shoulder 210 against which shoulder 104 on lower slips 136 are
slidably disposed. Thus, valve housing 206 may also be
referred to as a lower slip support 206.
Referring now also to FIG. 4B, a sealing means, such as
O-ring 212, provides sealing engagement between center mandrel
202 and valve housing 206.~~
Valve housing 206 defines a housing central opening
including a bore 214 therein with a closed lower end 216. At
the upper end of bare 214 is an annular recess 218. Valve
housing 204 defines a plurality of substantially transverse
ports 220 therethrough which intersect bore 214.
Slidably disposed in bore 214 in valve housing 206 is a
sliding valve 222. At. the upper end of sliding valve 222 are
a plurality of collet fingers 224 which initially engage
recess 218.
Sliding valve 22'~ defines a plurality of substantially
transverse ports 226 t:herei.n which intersect a valve central
opening 228 in the sliding valve. Valve central opening 228
is in communication with mandrel central opening 204 in center
mandrel 202. At the upper end of central opening 228 is a
chamf eyed shou lder 2 3 () .
As shown in FIG. 4B, sliding valve 222 is in an uppermost
closed position. It will be seen that the lower end of center
mandrel 202 prevents further upward movement of sliding valve
222. When sliding valve 222 is moved d~~wnwardly to an open
position, ports 226 are substantially aligned with ports 220
in valve housing 206. An alignment means, such as an
CA 02406259 2002-11-04
22
alignment bolt 232, Extends from valve housing 206 inwardly
between a pair of adjacent collet fingers 224. A sealing
means, such as O-ring 234, provides sealing engagement between
alignment bolt 232 and value housing 206. Alignment bolt 234
prevents rotation of sliding valve 222 within valve housing
204 and insures proper ali'~nment of ports 226 and 220 when
sliding valve 222 is in its downwardmost, open position.
The wall thickness of sliding valve 222 is sufficient to
accommodate a pair of spaced seal grooves 234 are defined in
the outer surface of sliding valve 222, and as seen in FIG.
4B, seal grooves 234 are disposed on opposite sides of ports
220 when sliding valve 222 is in the open position shown. A
sealing means, such as seal 236, is disposed in each groove
234 to provide sealing engagement between sliding valve 222
and bore 214 in valve housing 2.06.
Referring again to FTG. 4A, a tension sleeve 238 is
attached to the upper end of center mandrel 202 at threaded
connection 240. A threaded portion 242 of tension sleeve 238
extends upwardly from center mandrel 202 and is adapted for
engagement with a setting apparatus (not shown) of a kind
known in the art.
An internal seal 244 is disposed in the upper end of
center mandrel 202 below tension sleeve 238.
Fourth Packer Embodiment
Referring now to FIGS. 5A and 58, a fourth squeeze packer
embodiment is shown and generally designated by the numeral
300. As illustrated, fourth embodiment 300 has the same
CA 02406259 2002-11-04
23
center mandrel 202, and all of the components positioned on
the outside of center mandrel 202 are identical to those in
the second and third packer embodiments. Therefore, the same
reference numerals are used for these components. Tension
sleeve 238 and internal seal 244 positioned on the inside of
the upper end of center mandrel 202 are also substantially
identical to the corresponding components in third embodiment
packer 200 and therefore shown with the same reference
numerals.
The difference between fourth packer embodiment 300 and
third packer embodiment 200 is that in the fourth embodiment
shown in FIGS. 5A and 5B, the lower end of center mandrel 202
is attached to a different valve housing 302 at threaded
connection 304. Shoulder 140 on each lower slip I36 slidingly
engages an upwardly and inwardly tapered shoulder 306 on the
top of valve housing 302. Thus, valve housing 302 may also be
referred to as Lower slip support 302.
Referring now to ~'IG. 5B, a sealing means, such as O-ring
308, provides sealing engagement between the lower end of
center mandrel 202 and valve housing 3U2.
Valve housing 3U2 defines a housing central opening
including a bore 310 therein with a closed lower end 312. A
bumper seal 314 is disposed adjacent to end 312.
Valve housing 3U2 defines a plurality of substantially
transverse ports 316 therethrough which intersect bore 310.
A sliding valve 318 is dispos~:d in bore 310, and is shown in
an uppermost, closed pasitioz~ ire FIG. 5B. It will be seen
CA 02406259 2002-11-04
24
that the lower end of center mandrel 202 prevents upward
movement of sliding valve 318. Sliding valve 318 defines a
valve central opening 320 therethrough which is in
communication with mandrel central opening 204 in center
mandrel 202. At the upper end of valve central opening 320 in
sliding valve 318 is an upwardly facing chamfered shoulder
322.
On the outer surface of sliding valve 318, a pair of
spaced seal grooves 324 are defined, In the closed position
shown in FIG. 5B, seal grooves 324 are on opposite sides of
ports 316 in valve housing 302. A sealing means, such as seal
326, is disposed in each seal groove 324 and provides sealing
engagement between sliding valve 318 and bore 310 in valve
housing 302.
When sliding valve 318 is opened, as will be further
described herein, the sliding valve 318 is moved downwardly
such that upper end 328 thereof is below ports 316 in valve
housing 302. Downward movement of sliding valve 318 is
checked when lower end 330 thereof contacts bumper seal 314.
Bumper seal 314 is made of a res.i.l ien~t material which cushions
the impact of sliding valve 318 thereon.
Fifth Packer Embodiment
Referring now to FIGS. 6A and 6B, a fifth squeeze packer
embodiment is shown and generally designated by the numeral
400. As illustrated, fifth packer embodiment 400 incorporates
the same thick cross-sectional center mandrel 102 as does
second packer embodiment 100 shown in fIG;~. 3A and 3B. Also,
CA 02406259 2002-11-04
the external components positioned on center mandrel 102 are
the same as in the second, third and fourth packer
embodiments, so the same reference numerals will be used.
Further, tension sleeve 1~4 and internal seal 180 in second
embodiment 100 are also incorporated in fifth embodiment 400,
and therefore these same a~eference numerals have also been
used.
The difference between fifth packer embodiment 400 and
second embodiment 100 is that the lower end of center mandrel
102 is attached to a lower slip support 402 at threaded
connection 404. Shoulders 140 on lower slips 136 slidingly
engage an upwardly and inwardly tapered shoulder 406 at the
upper end of lower slip support 402.
Referring now to ~'.IG. 6B, a sealing means, such as O-ring
408, provides sealing engagement between the lower end of
center mandrel 102 and. lower slip support 402.
Lower slip support 402 defines a first bore 410 therein
and a larger second bor_-e 422 spaced down~rardly from the first
bore. A tapered seat surface 414 extends between first bore
410 and second bore 412.
The lower end of lower support 402 is attached to a valve
housing 416 at threaded connection 418. Valve housing 416
defines a first bore 420 and a smaller second bore 422
therein. An upwardly facing annular shoulder 424 extends
between first bore 420 and second bore 42'.?. Below second bore
422, valve housing 416 defines a third bore 426 therein with
an internally threaded surface 428 forming a port at the lower
CA 02406259 2002-11-04
26
end of the valve housing.
Disposed in first bare 420 in valve housing 416 is a
valve body 430 with an upwardly facing annular shoulder 432
thereon. An elastomeric valve seal 434 and a valve spacer
436, which provides support for the valve seal, are positioned
adjacent to shoulder 432 on~valve body 430. A conical valve
head 438 is positioned above valve seal 434 and is attached to
valve body 430 at threaded connection 440. It will be seen by
those skilled in the art that valve seal 434 is adapted for
sealing engagement with seat surface 414 in lower slip support
402 when valve body 430 is moved upwardly.
The lower end of valve body 430 is connected to a valve
holder 442 by one or more pins 444. Valve holder 442 is
disposed in second bore 422 of valve housing 416. A sealing
means, such as D-ring 446 provides sealing engagement between
valve holder 442 and valve housing 416.
Above shoulder 424 in valve housing 416, valve body 430
has a radially outwar°dly extending flange 448 thereon. A
biasing means, such as spring 450, is disposed between flange
448 and shoulder 424 foci biasing valve body 430 upwardly with
respect to valve housing 416.
Valve holder 442 defines a first bore 452 and a smaller
second bore 454 therein with an upwardly facing chamfered
shoulder 456 extending therebetween. A ball 458 is disposed
in valve holder 442 and is adapted for engagement with
shoulder 456.
CA 02406259 2002-11-04
27
First Bridae Plua Embodiment
Referring now to FIG. 7, a first bridge plug embodiment
of the present invention is shown and generally designated by
the numeral 500. First bridge plug embodiment 500 comprises
the same center mandrel 102 and the external components
positioned thereon as does4the second packer embodiment 100.-
Therefore, the reference numerals for these components shown
in FIG. 7 are the same as in FIG. 3A.
The lower end of center mandrel 102 in first bridge plug
embodiment 500 is connected to a lower slip support 502 at
threaded connection 504. An upwardly and inwardly tapered
shoulder 506 on lower slip support 502 engages shoulders 140
on lower slips 136. As with the other embodiments, slips 136
axe adapted for sliding alc>ng shoulder 706.
Lower slip support 502 defines a bore 508 therein which
is in communication wi ~h mandrel central opening 104 in center
mandrel 102.
A bridging plug 51o is disposed in the upper portion of
mandrel central opening 104 in center mandrel 102 and is
sealingly engaged with internal seal 180. A radially
outwardly extending flange 512 prevents bridging plug 510 from
moving downwardly through center mandrel 102.
Above bridging plug 510 is tension sleeve 174, previously
described far second packer embodiment 100.
Second Br~dae Plua Embodiment
Referring now to FIG. 8, a second bridge plug embodiment
of the present invention is shown and generally designated by
CA 02406259 2002-11-04
28
the numeral 600. Second bridge plug embodiment 600
uses the same thin cross-sectional mandrel 202 as
does third packer eembodiment 200 shown in FIG. 4A.
Also, the extE>rna.l component:s ,aositioned on center
mandrel 202 are the same as pre~.riously described, so
the same reference numerals are i..~sed in FIG. 8.
In second bridge plug embodiment 600, the lower
end of center mandrel 202 is t~ttached to the same
lower slip support 502 as first bridge plug
embodiment 500 at threaded con.n~~ction 602. It will
be seen that bare 508 irx lower sip support 502 is in
communication with mandrel central opening 204 in
center mandrel 202.
A bridging plug 604 is positioned in the upper
end of mandrel centhal opening 204 in center mandrel
202. A shoul_dei: 608 in central. opening 204 prevents
downward movement of bridging plug 604, A sealing
means, such as a plurality of O-rings 606, provide
sealing engagement between bri~~c~ing plug 604 and
center mandrel 202.
Tension sleeve 2.38, previously described, is
positioned above bridging plug 604.
Setting, And O~er~tion _Of_'Ihe A paratus
Downhole tool apparatus 10 is positioned in well
bore 12 and set into engagement therewith in a manner
similar to prior art devices made with metallic
c;omponent.s. Fc>r example, a pric3r art apparatus and
setting thereof: is disc-Losed in the above-referenced
U. S. Patent No. 4, 15~',.., 875 to Sull~way.
CA 02406259 2002-11-04
29
For first packer embodiment 20, the setting tool pulls
upwardly on tension sleeve 62, and thereby on mandrel 22,
while holding lock ring housing 24. The lock ring housing is
thus moved relatively downwardly along mandrel 22 which forces
upper slips 28 outwardly and shears screws 36, pushing upper
slip wedge 32 downwardly against packer° elements 40 and 42.
Screws 50 are also sheared and lower slip wedge 46 is pushed
downwardly toward lower slip support 58 to force lower slips
54 outwardly. Eventually, upper. slips 28 and lower slips 54
are placed in gripping engagement with well bore 12 and packer
elements 40 and 42 are in sealing engagement with the well
bore. The action of upper slips 28 and 54 prevent packer 20
from being unset. As will. be seen by Chase skilled in the
art, pressure below packer 2o cannot fozmce the packer out of
well bore 12, but instead, causes it to be even more tightly
engaged.
Eventually, in the setting operation, tension sleeve 62
is sheared, so the setting tool may be removed from the well
bore.
The setting of second packer embodiment 100, third packer
embodiment 200, fourth packer embodiment 300, fifth packer
embodiment 400, first bridge plug embodiment 5U0 and second
bridge plug embodiment 600 is similar to that for first packer
embodiment 20. The setting tool is attached to either tension
sleeve 174 or 238. During setting, the setting tool pushes
downwardly on upper slip support 110, thereby shearing shear
pin 112. Upper slips 116 are moved downwardly with respect to
CA 02406259 2002-11-04
upper slip wedge 126. Tapers 120 and upper slips 116 slide
along upper slip wedge 126, and shoulders 118 on upper slips
116 slide along shoulder 114 on upper slip support 110. Thus,
upper slips 116 are moved radially outwardly with respect to
center mandrel 102 or 202 such that edges 124 of inserts 122
grippingly well bore 12.
Also during the setting operation, upper slip 126 is
forced downwardly, shearing shear pin 128. This in turn
causes packer elements 40 a»d 42 to be squeezed outwardly into
sealing engagement with the well bore.
The lifting on center mandrel 102 or 202 causes the lower
slip support (valve housing 144 in first packer embodiment
100, valve housing 206 in second packer embodiment 200, valve
housing 302 in fourth packer embodimE~nt 300, lower slip
support 402 in fifth packer embodiment 400, and lower slip
support 502 in first bridge plug embodiment 500 and second
bridge plug embodiment 600) to be moved up and lower slips 136
to be moved upwardly with respect to lower slip wedge 130.
Tapers 134 in lower slips 136 slide along lower slip wedge
130, and shoulders 140 on lower slips 136 slide along the
corresponding shoulder 142, 210, 306, 406, or 506. Thus,
lower slips 136 are moved radially outwardly with respect to
center mandrel 102 or 202 sa that inserts 138 grippingly
engage well bare 12.
Also during the setting operation, lower slip wedge 130
is forced upwardly, shearing shear pin 132, to provide
additional squeezing force on packer elements 40 and 42.
CA 02406259 2002-11-04
31
The engagement of inserts 122 in upper slips 116 and
inserts 138 in lowe~x~ slips 136 with well bore 12 prevent
packers 100, 200, 300, 400 and bridge plugs 500, 600 from
coming unset.
Once any of packers 20, 100, 200, 300, 400 are set, the
valves therein may be actuated in a manner known in the art.
Sliding valve 164 in second packer embodiment 126, and sliding
valve 22 in third packer embodiment 200 are set in a similar,
if not identical manner. sliding valve 318 in fourth packer
embodiment 300 is also set in a similar manner, but does not
utilize collets, nor is alignment of sliding valve 318 with
respect to ports 316 in valve housing 302 important. Sliding
valve 318 is simply moved below ports 316 to open the valve.
Bumper seal 314 cushions the downward movement of sliding
valve 318, thereby minimizing the possibility of damage to
sliding valve 318 or valve housing 302 during an opening
operation.
In fifth packer embodiment 400, the valve assembly
comprising valve body 432, valve seal 434, valve spacer 436,
valve head 438 and valve holder 442 is ~~perated in a manner
substantially identical to that of the Ilal.liburton EZ Drills
squeeze packer of the prior art.
Drillinc,~ Out The Packer Apparatus
Drilling out any embodiment of downhole tool 10 may be
carried out by using a standard drill bit at the end of tubing
string 16. Cable tool drilling may also be used. With a
standard "tri-cone" drill bit, the drilling operation is
CA 02406259 2002-11-04
32
similar to that of the prior art except that variations in
rotary speed and bit weight are not critical because the non-
metallic materials are considerably softer than prior art cast
iron, thus making tool 10 much easier to drill out. This
greatly simplifies the drilling operation and reduces the cost
and time thereof. ~' "
In addition to standard tri-cone drill bits, and
particularly if tool 10 is constructed utilizing engineering
grade plastics for the mandrel as well as for slip wedges,
slips, slip supports and housings, alternate types of drill
bits may be used which would be impossible for tools
constructed substantially of cast iron. For example,
polycrystalline diamond compact (PDC) bits may be used. Drill
bit 14 in FIG. 1 is illustrated as a FDC bit. Such drill bits
have the advantage of having no moving parts which can jam up.
Also, if the well bore itself was drilled with a PDC bit, it
is not necessary to replace it with another or different type
bit in order to drill out tool 10.
While specific sdueeze packer and bridge plug
configurations of packing apparatus 10 has been described
herein, it will be understood by those skilled in the art that
other tools may also be constructed utilizing components
selected of non-metallic materials, such as engineering grade
plastics.
Additionally, components of the various packer
embodiments may be interchanged. For example, thick cross-
sectional center mandrel 102 may be uved with valve housing
CA 02406259 2002-11-04
33
206 in second packer embodiment 200 or valve housing 302 in
fourth packer embodiment 300. Similarly, thin cross-sectional
center mandrel 202 could be used with valve body 144 in second
packer embodiment 100 or lower slip support 402 and valve
housing 416 in fifth packer embodiment 400. The intent of the
invention is to provide devises of flexible design in which a
variety of configurations may be used.
It will be seen, therefore, that the downhole tool packer
apparatus and methods of drilling thereof of the present
invention are well adapted to carry out the ends and
advantages mentioned as well as thaw inherent therein. While
presently preferred embodiments of the apparatus and various
drilling methods have been discussed for the purposes of this
disclosure, numerous changes in the arrangement and
construction of parts and the steps of the methods may be made
by those skilled in the art. In particular, the invention is
not intended to be limited to squeeze packers or bridge plugs.
AlI such changes are encompassed within the scope and spirit
of the appended claims.
