U.S. patent application number 14/195218 was filed with the patent office on 2014-09-11 for millable fracture balls composed of metal.
This patent application is currently assigned to Weatherford/Lamb, Inc.. The applicant listed for this patent is Weatherford/Lamb, Inc.. Invention is credited to Cesar G. Garcia, Michael Rossing.
Application Number | 20140251594 14/195218 |
Document ID | / |
Family ID | 50434284 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140251594 |
Kind Code |
A1 |
Garcia; Cesar G. ; et
al. |
September 11, 2014 |
Millable Fracture Balls Composed of Metal
Abstract
A ball is used for engaging in a downhole seat and can be milled
out after use. The ball has a spherical body with an outer surface.
An interior of the spherical body is composed of a metallic
material, such as aluminum. The spherical body has a plurality of
holes formed therein. The holes extend from at least one common
vertex point on the outer surface of the spherical body and extend
at angles partially into the interior of the spherical body.
Inventors: |
Garcia; Cesar G.; (Katy,
TX) ; Rossing; Michael; (Spirng, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weatherford/Lamb, Inc. |
Houston |
TX |
US |
|
|
Assignee: |
Weatherford/Lamb, Inc.
Houston
TX
|
Family ID: |
50434284 |
Appl. No.: |
14/195218 |
Filed: |
March 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61774729 |
Mar 8, 2013 |
|
|
|
Current U.S.
Class: |
166/193 ; 29/592;
29/899 |
Current CPC
Class: |
Y10T 29/49712 20150115;
Y10T 29/49 20150115; E21B 34/14 20130101; E21B 33/1204
20130101 |
Class at
Publication: |
166/193 ; 29/592;
29/899 |
International
Class: |
E21B 33/12 20060101
E21B033/12 |
Claims
1. A plug for engaging in a downhole seat and being milled out
after use, the plug comprising: a body having an outer surface and
an interior, the body having a plurality of holes formed therein,
the holes extending from at least one common vertex point on the
outer surface of the body and extending at angles partially into
the interior of the body.
2. The plug of claim 1, wherein the plug is a ball, and wherein the
body is spherical.
3. The plug of claim 1, wherein the body is composed of a metallic
material.
4. The plug of claim 3, wherein the metallic material comprises
aluminum.
5. The plug of claim 1, wherein the at least one common vertex
point comprises at least one tap hole defined in the outer surface
of the body, and wherein the plurality of holes comprises a
plurality of angled holes formed at angles into the interior from
the at least one tap hole.
6. The plug of claim 1, wherein the at least one common vertex
point comprises common vertex points disposed on opposing sides of
the body.
7. The plug of claim 6, wherein the plurality of holes comprises: a
first set of angled holes formed at angles into the interior from
one of the common vertex points on one of the opposing sides; and a
second set of angled holes formed at angles into the interior from
the other of the common vertex points on the other of the opposing
sides.
8. The plug of claim 7, wherein the first and second sets of angled
holes are offset from one another.
9. The plug of claim 1, wherein at least a portion of the holes
comprise a filler material disposed therein.
10. A method of manufacturing a plug for engaging in a downhole
seat and being milled out after use, the method comprising: forming
a body having an outer surface and an interior, forming a plurality
of holes in the body by extending the holes from at least one
common vertex point on the outer surface of the body and extending
the holes at angles partially into the interior of the body.
11. The method of claim 10, wherein the plug is a ball, and wherein
the body is spherical.
12. The method of claim 10, wherein the body is composed of a
metallic material.
13. The method of claim 12, wherein the metallic material comprises
aluminum.
14. The method of claim 10, wherein extending the holes from the at
least one common vertex point on the outer surface of the body
comprises forming at least one tap hole in the outer surface of the
body,
15. The method of claim 14, wherein extending the holes at angles
partially into the interior of the spherical body comprises forming
a plurality of angled holes formed at angles into the interior from
the at least one tap hole.
16. The method of claim 10, wherein extending the holes from the at
least one common vertex point on the outer surface of the body
comprises forming tap holes on opposing sides of the body.
17. The method of claim 16, wherein extending the holes at angles
partially into the interior of the body comprises: forming a first
set of angled holes at angles into the interior from one of the tap
holes; and forming a second set of angled holes at angles into the
interior from the other tap hole.
18. The method of claim 17, wherein the first and second sets of
angled holes are offset from one another.
19. The method of claim 10, further comprising filling at least a
portion of the holes with a filler material.
20. A plug for engaging in a downhole seat and being milled out
after use, the plug comprising: a body having an outer surface, a
top end of the body having a fin disposed thereon, and a bottom end
of the body opposite the top end having a sealing area on the outer
surface, the bottom end being truncated below the sealing area.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of the U.S. Prov. Appl.
61/774,729, filed 8 Mar. 2013, which is incorporated herein by
reference.
BACKGROUND OF THE DISCLOSURE
[0002] In a staged fracturing operation, multiple zones of a
formation need to be isolated sequentially for treatment. To
achieve this, operators install a fracturing assembly down the
wellbore, which typically has a top liner packer, open hole packers
isolating the wellbore into zones, various sliding sleeves, and a
wellbore isolation valve. When the zones do not need to be closed
after opening, operators may use single shot sliding sleeves for
the fracturing treatment. These types of sleeves are usually
ball-actuated and lock open once actuated. Another type of sleeve
is also ball-actuated, but can be shifted closed after opening.
[0003] Initially, operators run the fracturing assembly in the
wellbore with all of the sliding sleeves closed and with the
wellbore isolation valve open. Operators then deploy a setting ball
to close the wellbore isolation valve. This seals off the tubing
string of the assembly so the packers can be hydraulically set. At
this point, operators rig up fracturing surface equipment and pump
fluid down the wellbore to open a pressure actuated sleeve so a
first zone can be treated.
[0004] As the operation continues, operates drop successively
larger balls down the tubing string and pump fluid to treat the
separate zones in stages. When a dropped ball meets its matching
seat in a sliding sleeve, the pumped fluid forced against the
seated ball shifts the sleeve open. In turn, the seated ball
diverts the pumped fluid into the adjacent zone and prevents the
fluid from passing to lower zones. By dropping successively
increasing sized balls to actuate corresponding sleeves, operators
can accurately treat each zone up the wellbore.
[0005] FIG. 1A shows an example of a sliding sleeve 10 for a
multi-zone fracturing system in partial cross-section in an opened
state. This sliding sleeve 10 is similar to Weatherford's
ZoneSelect MultiShift fracturing sliding sleeve and can be placed
between isolation packers in a multi-zone completion. The sliding
sleeve 10 includes a housing 20 defining a bore 25 and having upper
and lower subs 22 and 24. An inner sleeve or insert 30 can be moved
within the housing's bore 25 to open or close fluid flow through
the housing's flow ports 26 based on the inner sleeve 30's
position.
[0006] When initially run downhole, the inner sleeve 30 positions
in the housing 20 in a closed state. A breakable retainer 38
initially holds the inner sleeve 30 toward the upper sub 22, and a
locking ring or dog 36 on the sleeve 30 fits into an annular slot
within the housing 20. Outer seals on the inner sleeve 30 engage
the housing 20's inner wall above and below the flow ports 26 to
seal them off.
[0007] The inner sleeve 30 defines a bore 35 having a seat 40 fixed
therein. When an appropriately sized ball lands on the seat 40, the
sliding sleeve 10 can be opened when tubing pressure is applied
against the seated ball 40 to move the inner sleeve 30 open. To
open the sliding sleeve 10 in a fracturing operation once the
appropriate amount of proppant has been pumped into a lower
formation's zone, for example, operators drop an appropriately
sized ball B downhole and pump the ball B until it reaches the
landing seat 40 disposed in the inner sleeve 30.
[0008] Once the ball B is seated, built up pressure forces against
the inner sleeve 30 in the housing 20, shearing the breakable
retainer 38 and freeing the lock ring or dog 36 from the housing's
annular slot so the inner sleeve 30 can slide downward. As it
slides, the inner sleeve 30 uncovers the flow ports 26 so flow can
be diverted to the surrounding formation. The shear values required
to open the sliding sleeves 10 can range generally from 1,000 to
4,000 psi (6.9 to 27.6 MPa).
[0009] Once the sleeve 10 is open, operators can then pump proppant
at high pressure down the tubing string to the open sleeve 10. The
proppant and high pressure fluid flows out of the open flow ports
26 as the seated ball B prevents fluid and proppant from
communicating further down the tubing string. The pressures used in
the fracturing operation can reach as high as 15,000-psi.
[0010] After the fracturing job, the well is typically flowed
clean, and the ball B is floated to the surface. Then, the ball
seat 40 (and the ball B if remaining) is milled out. The ball seat
40 can be constructed from cast iron to facilitate milling, and the
ball B can be composed of aluminum or a non-metallic material, such
as a composite. Once milling is complete, the inner sleeve 30 can
be closed or opened with a standard "B" shifting tool on the tool
profiles 32 and 34 in the inner sleeve 30 so the sliding sleeve 10
can then function like any conventional sliding sleeve shifting
with a "B" tool. The ability to selectively open and close the
sliding sleeve 10 enables operators to isolate the particular
section of the assembly.
[0011] When aluminum balls B are used, more sliding sleeves 10 can
be used downhole for the various stages because the aluminum balls
B can have a close tolerance relative to the inner diameter for the
seats 40. For example, forty different increments can be used for
sliding sleeves 10 having solid seats 40 used to engage aluminum
balls B. However, an aluminum ball B engaged in a seat 40 can be
significantly deformed when high pressure is applied against it.
Any variations in pressuring up and down that allow the aluminum
ball B to seat and to then float the ball B may alter the shape of
the ball B, compromising its seating ability or its ability to
float to the surface after use.
[0012] Additionally, aluminum balls B if left downhole can be
particularly difficult to mill out of the sliding sleeve 10 due to
their tendency of rotating during the milling operation. For
example, FIG. 1C shows a mill 50 inserted into a sliding sleeve's
housing 20 after milling a ball B from an uphole sliding sleeve.
Operators use the mill 50 to mill through all the balls B and seats
40 to gain full tubing access.
[0013] One problem with using aluminum balls B can be the long mill
up times required per zone. For instance, milling just one frac
stage when a solid aluminum ball is used can take up to an hour.
During mill up, larger aluminum balls B push through the seats as a
large quarter segment S of the ball. This segment S travels down to
the next seat 40 and contacts the next ball B, as shown in FIG. 1C.
When the mill 50 reaches this sliding sleeve, the aluminum segment
S and the existing ball B tend to spin on each other and do not
allow the mill 50 to grab and mill up the components quickly. As
are result, milling the seats 40 and aluminum balls B can be longer
than desired, which delays operators' ability to put the well in
production.
[0014] Using non-metal balls may avoid the problem of longer
milling times because the non-metal balls break apart easier during
mill up. Yet, as noted previously, these non-metal balls may not
hold the desired operating pressures and may not provide as many
stages as can be obtained with the minimized aluminum ball and seat
engagement.
[0015] The subject matter of the present disclosure is directed to
overcoming, or at least reducing the effects of, one or more of the
problems set forth above.
SUMMARY OF THE DISCLOSURE
[0016] A plug is used for engaging in a downhole seat and is milled
out after use. The plug has a body with an outer surface and an
interior. The plug can be a ball, and the body can be spherical.
Additionally, the plug's body can be composed of a metallic
material, such as aluminum.
[0017] The body has a plurality of holes formed therein. In
particular, the holes extend from at least one common vertex point
on the outer surface of the body and extend at angles partially
into the interior of the body. The at least one common vertex point
can be at least one tap hole defined in the outer surface of the
body, and the plurality of holes can be a plurality of angled holes
formed at an angle into the interior from the at least one tap
hole. At least a portion of the holes can have a filler material
disposed therein.
[0018] In one implementation, common vertex points disposed on
opposing sides of the body can be used. In this case, the holes
include a first set of angled holes formed at an angle into the
interior from one of the common vertex points on one of the
opposing sides. Additionally, the holes include a second set of
angled holes formed at an angle into the interior from the other of
the common vertex points on the other of the opposing sides. The
first and second sets of angled holes can be offset from one
another.
[0019] Manufacturing the plug involves forming the body with the
outer surface and the interior. The holes are formed in the body by
extending the holes from at least one common vertex point on the
outer surface of the body and extending the holes at angles
partially into the interior of the body.
[0020] To extend the holes from the at least one common vertex
point on the outer surface of the body, the method can involve
forming at least one tap hole in the outer surface of the body and
forming a plurality of angled holes formed at an angle into the
interior from the at least one tap hole. In one implementation, tap
holes can be formed on opposing sides of the body. In this way, a
first set of angled holes can be formed at an angle into the
interior from one of the tap holes, and a second set of angled
holes can be formed at an angle into the interior from the other
tap hole. These first and second sets of angled holes can be offset
from one another.
[0021] The foregoing summary is not intended to summarize each
potential embodiment or every aspect of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1A illustrates a sliding sleeve having a ball engaged
with a seat to open the sliding sleeve according to the prior
art.
[0023] FIG. 1B illustrates a close up view of the sliding sleeve in
FIG. 1B.
[0024] FIG. 1C illustrates a close up view of a mill entering the
sliding sleeve of FIG. 1B.
[0025] FIGS. 2A-2C illustrate cross-sectional views of a first
embodiment of a metallic ball according to the present disclosure
for actuating a sliding sleeve.
[0026] FIGS. 3A-3C illustrate cross-sectional views of a second
embodiment of a metallic ball according to the present disclosure
for actuating a sliding sleeve.
[0027] FIGS. 4A-4C illustrate cross-sectional views of a third
embodiment of a metallic ball according to the present disclosure
for actuating a sliding sleeve.
[0028] FIGS. 5A-5C illustrate cross-sectional views of a fourth
embodiment of a metallic ball according to the present disclosure
for actuating a sliding sleeve.
[0029] FIGS. 6A-6C illustrates a detailed view of a mill entering a
sliding sleeve having the metallic ball of FIGS. 3A-3C.
[0030] FIG. 7 illustrates segments or shards remaining after
milling a ball according to the present disclosure.
[0031] FIG. 8 illustrates yet another embodiment of a metallic ball
for actuating a sleeve and facilitating mill out according to the
present disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0032] Fracture balls composed of metal, and particularly aluminum,
have material removed from the ball's interior. The removal of the
material can be done in various ways. In general, holes can drilled
to a specified depth in the ball, but the holes do not create a
through-hole in the ball, as this would compromise the sealing
ability of the ball. Instead, the holes create voids (not
through-holes) and allow the ball to stay intact during fracturing
operations. The holes in the ball also allow the ball to break up
easier during milling operations.
[0033] As noted in the background of the present disclosure, mill
out of a solid metal (aluminum) ball may cause a large segment of
the ball to push through the seat before being fully milled. The
partially milled segment then travels to the next ball/seat below
it. The segment and ball then tend spin when the mill reaches them,
which increases the mill up times. However, the disclosed ball
having the partial hole(s) defined therein tends to break up into
smaller pieces that allow the mill to grab them when it travels to
the lower seat. Although the partial hole(s) may be beneficial for
milling, the ball must still be capable of properly seating on the
ball seat and preventing leakage and must be able to withstand the
increased pressures of the fracture operations.
[0034] FIGS. 2A-2C illustrate cross-sectional views of a first
embodiment of a ball 100 according to the present disclosure for
actuating a sliding sleeve. The ball 100 has a solid, spherical
body 102 composed of a metallic material, including, but not
limited to, aluminum, aluminum alloy, steel, brass, aluminum
bronze, a metallic nanostructure material, cast iron, etc. The
metallic material is preferably one that can be floated to the
surface and can be milled if necessary. Of course, the ball 100 can
be composed of any suitable material, even ceramics, plastics,
composite materials, phenolics, Torlon, Peek, thermoplastics, or
the like.
[0035] Voids, spaces, or holes are defined in the body 102 to
facilitate milling of the ball 100 when disposed in a ball seat of
a tool, such as a sliding sleeve. Because the ball 100 has the
purposes of sealingly engaging the ball seat in the sliding sleeve,
the ball 100 preferably is configured to maintain or produce a
sufficient seal with the ball seat when seated therein. Therefore,
the voids, spaces, or holes do not pass entirely through the body
102. Instead, as shown in FIGS. 2A-2C, a tap hole 110 is drilled in
one side of the ball's body 102. The depth of this tap hole 110 is
preferably less than half the diameter of the ball 100, although it
could be deeper in a given implementation.
[0036] Drilled off at angles from the tap hole 110 are a plurality
of angled holes 112--four such angled holes 112 are shown in the
ball 100 of FIGS. 2A-2C. The tap hole 110, although it may provide
a desired void in the ball's body 102, is used primarily to provide
a common vertex point V near the surface 104 of the ball 100 from
which to form the angled holes 112. In this way, the multiple
angled holes 112 do not tap multiple points on the ball's outer
surface 104, which could compromise the sealing capability of the
ball 100 when seated.
[0037] All the same, the tap hole 110 can be left unplugged and act
as a suitable void. Alternatively, the tap hole 110 can plugged
with material, such as epoxy, resin, solder, plastic, rubber, the
same metal material as the body 102, other type of metal than the
body 102, or the like. The angled holes 112 can even be filled at
least partially with filler material that can be readily
milled.
[0038] Each angled hole 112 can be angled at about 45-degrees from
the centerline of the tap hole 110, and the angled holes 112 may be
offset at about 90-degrees from one another around the tap hole
110. As with the tap hole 110, the angled holes 112 may extend to
less than the mid-section of the ball's body 102, but this may vary
for a given implementation. The ball 100 in FIG. 2A-2C essentially
defines holes 110/112 or voids in half the ball's body 102.
[0039] For some exemplary dimensions for the ball 100 having a
diameter of about 3-in., the tap hole 110 can be about 3/8-in. wide
and can extend about 1/3 of the diameter (e.g., about 1-in.) of the
body 102. The angled holes can be about 1/4-in. wide and can extend
about 1.75-in. in length. Other sized balls 100 would have other
dimensions, of course. In any event, balls 100 having a diameter of
about 2-in. or greater would be best suited for the types of holes
disclosed herein simply because balls with smaller diameters are
already easier to mill.
[0040] FIGS. 3A-3C illustrate cross-sectional views of a second
embodiment of a ball 100 according to the present disclosure for
actuating a sliding sleeve. This ball 100 is similar to that
discussed previously, but tap holes 110a-b are defined in opposing
sides of the ball's body 102. Each tap hole 110a-b has a plurality
of angled holes 112a-b in a manner similar to that discussed
previously. Preferably as shown, the angled holes 112a-b are offset
from one another around the axis defined by the tap holes 110a-b so
that the opposing holes 112a-b do not meet with one another inside
the body 102. Because the tap holes 110a-b are offset 180-degrees
on opposite sides, it is less likely that both will engage the edge
of a seat when landed thereon.
[0041] As before, the tap holes 110a-b can primarily provide common
vertices Va-Vb from which the opposing angled holes 112a-b can be
formed so that multiple tap points do not need to be made in the
ball's surface 104. The ball 100 in FIG. 3A-3C essentially defines
holes 110a-b/112a-b or voids throughout the interior of the entire
ball's body 102. If desired, the holes 110a-b/112a-b can be left
empty or can be filled with a filler material, such as an epoxy,
resin, plastic, rubber, other type of metal than the body's metal,
or the like.
[0042] FIGS. 4A-4C illustrate cross-sectional views of a third
embodiment of a metallic ball 100 according to the present
disclosure for actuating a sliding sleeve. This ball 100 is similar
to that discussed above with reference to FIGS. 2A-2C in that a tap
hole 110 and angled holes 114 are defined in one side of the ball
100. Rather than having four angled holes as in the previous
embodiment, this ball 100 has three angled holes 114 drilled at
about every 120-degrees around the tap hole 110.
[0043] In other differences illustrated, the angled holes 112 can
be drilled at a shallower angle from the tap hole 110.
Additionally, the ends of the angled holes 112 can extend beyond
the midpoint of the ball's body 102. Thus, the angled holes 112
extend nearly to the opposing side of the ball's body 102.
[0044] FIGS. 5A-5C illustrate cross-sectional views of a fourth
embodiment of a metallic ball 100 according to the present
disclosure for actuating a sliding sleeve. This ball 100 has tap
holes 110a-b and angled holes 112a-b similar to the ball 100 in
FIGS. 4A-4C and has two sets of such holes 110a-b/112a-b on
opposing sides of the ball 100 similar to the ball 100 in FIGS.
3A-3C.
[0045] As can be seen from the various arrangements of holes in
FIGS. 2A through 5C, the metallic ball 100 can have a plurality of
holes (e.g., 112) formed or drilled partially therein. Preferably,
the holes 112 do not pass entirely through the ball's body 102 and
do not intersect one another 102. Instead, the holes 112 are made
from one or more common vertices V near the surface 104 of the ball
100 and spread out from one another in different directions from
the common vertex V. When the holes 112 are formed from two or more
common vertices Va-Bb as in FIGS. 3A-3C and 5A-5C, the opposing
holes 112a-b preferably pass between each other in a fit
pattern.
[0046] In general, the ball 100 (if solid) would have about
10.times. the structural strength required to achieve its purposes
downhole. Removing material with the holes 110/112 could reduce the
structural strength to perhaps 2 to 3 times what is needed. In any
event, a given ball 100 with the holes 110/112 is preferably
capable of withstanding at least 7,000-psi, and more preferably
10,000-psi, without collapsing on itself. Of course, the different
diameters of balls and seats used and the associated materials will
govern any such variables.
[0047] FIGS. 6A-6C illustrates a detailed view of a mill 50
entering a sliding sleeve having the ball 100 of FIGS. 3A-3C. As
shown in FIG. 6A, the ball 100 is engaged in the seat 40. The tap
holes 110 and/or angled holes 112 of the ball 100 can be filled
with filler material (not shown). After fracturing, the ball 100
may be deformed by the applied pressure in ways not specifically
shown here. For example, an outer ring may form around the ball 100
where it engages the shoulder of the seat 40, and the top of the
ball 100 may be compressed outward. In any event, operators
eventually run a milling tool 50 down the tubing string to mill out
the ball 100 and seat 40. In general, the mill 50 can use any
suitable type of bit, such as a PCD type bit.
[0048] As shown in FIG. 6B, the mill 50 engages the ball 100 and
bears down against it. As the mill 50 rotates, the voids in the
metal body 102 of the ball 100 allow the edges and teeth of the
mill 50 to engage the ball 100 so that the mill 50 can bite, grab,
break, and shave away the material of the ball 100 more readily
than found with a solid metal ball. Notably, the voided ball 100
may have less of a tendency to rotate with the rotation of the mill
50, which typically happens with a solid metal ball during milling
operations. Also, if a portion of the ball 100 remains intact, the
holes 110/112 can allow the portion to be split when the mill 50
applies weight because the holes 110/112 create fracture planes and
points for grinding up the ball 100.
[0049] Finally, as shown in FIG. 6C, the mill 50 can eventually
grind and break up the ball into shavings (not shown) and possible
chunks C that may then fall or be pushed through the seat 40.
Milling the aluminum ball B can take up to 10-min., depending of
the motor, bit, flow rates, and weight on bit (WOB) used, as well
as any environmental conditions.
[0050] Although these chunks C may pass to the next ball and seat
downhole, their irregular shape and fragmented nature makes them
easier to mill further when the mill 50 reaches the next ball and
seat arrangement downhole. The chunks C and any exposed holes on
the other ball create points of friction that can facilitate
milling. As an example of what possible chunks C may be left of a
metallic ball after milling and passing through a seat, FIG. 7
illustrates several chunks of an aluminum ball after being milled
out at least partially.
[0051] Again, some of the ball remains as chunks during milling
that can then pass through the seat before the mill 50 actually
grinds the entire ball and seat during milling operations. Rather
than producing a quarter segment of the ball B as encountered with
a solid metal ball when milled, the voided ball 100 produces less
uniform and less substantial chunks. One chunk is shown as being
flat in shape and as defining remnants of the various holes (112)
formed in the ball's body 102. This makes this chunk more
susceptible to further breaking and grinding during further milling
stages. Other chunks are smaller pieces removed from the voided
ball 100 during milling.
[0052] As an alternative to a spherical ball having holes to
facilitate milling, a metallic ball 200 as shown in FIG. 8 can also
engage in a seat of a sliding sleeve, yet facilitate mill out when
needed. The ball 200 includes a fin or tail 206 on one end of the
ball 200, which would correspond to the top of the ball 200 when
deployed. The base body 202 of the ball 200 is truncated, having a
large portion 204 removed to below the sealing area 208 where the
ball 200 would engage a seat's shoulder. The tail 206 keeps the
ball 200 oriented properly. When milled, however, less of a
spherical segment of the ball 200 would pass through the seat to
the next ball, which can avoid some of the problems encountered
during further milling stages.
[0053] Manufacture of the balls 100/200 disclosed herein can be
performed in a number of ways depending on the type of material
used. For example, the balls 110/200 can be formed by casting,
machining, drilling, and a combination thereof. Any holes 110/112
in the balls 110 can be formed by casting, machining, drilling, and
a combination thereof. These and other such manufacturing details
will be appreciated by one skilled in the art having the benefit of
the present disclosure.
[0054] The foregoing description of preferred and other embodiments
is not intended to limit or restrict the scope or applicability of
the inventive concepts conceived of by the Applicants. It will be
appreciated with the benefit of the present disclosure that
features described above in accordance with any embodiment or
aspect of the disclosed subject matter can be utilized, either
alone or in combination, with any other described feature, in any
other embodiment or aspect of the disclosed subject matter.
[0055] In exchange for disclosing the inventive concepts contained
herein, the Applicants desire all patent rights afforded by the
appended claims. Therefore, it is intended that the appended claims
include all modifications and alterations to the full extent that
they come within the scope of the following claims or the
equivalents thereof.
* * * * *