U.S. patent application number 12/470931 was filed with the patent office on 2010-11-25 for selective plug and method.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. Invention is credited to Richard Y. Xu.
Application Number | 20100294515 12/470931 |
Document ID | / |
Family ID | 43123803 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100294515 |
Kind Code |
A1 |
Xu; Richard Y. |
November 25, 2010 |
SELECTIVE PLUG AND METHOD
Abstract
A selective plug including a body; and a rotator configuration
in operable communication with the body capable of causing the plug
to selectively pass a number of borehole restrictions to reach and
engage a target restriction and method.
Inventors: |
Xu; Richard Y.; (Tomball,
TX) |
Correspondence
Address: |
CANTOR COLBURN LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
BAKER HUGHES INCORPORATED
HOUSTON
TX
|
Family ID: |
43123803 |
Appl. No.: |
12/470931 |
Filed: |
May 22, 2009 |
Current U.S.
Class: |
166/386 ;
166/192 |
Current CPC
Class: |
E21B 33/134 20130101;
E21B 43/26 20130101; E21B 23/006 20130101 |
Class at
Publication: |
166/386 ;
166/192 |
International
Class: |
E21B 33/12 20060101
E21B033/12 |
Claims
1. A selective plug comprising: a body; a rotator configuration in
operable communication with the body capable of causing the plug to
selectively pass a number of borehole restrictions to reach and
engage a target restriction.
2. The selective plug as claimed in claim 1 wherein the rotator
configuration is in operable communication with a collet.
3. The selective plug as claimed in claim 2 wherein the collet
includes a lug that extends into the rotator.
4. The selective plug as claimed in claim 2 wherein the rotator
includes a J-Slot configuration thereon responsive to movement of
the collet.
5. The selective plug as claimed in claim 1 wherein the rotator
configuration further includes a key interactive with the rotator
configuration to prevent rotation thereof after a selected number
of increments.
6. The selective plug as claimed in claim 5 wherein the key
interacts with one of a plurality of step profile teeth.
7. The selective plug as claimed in claim 1 wherein the body
includes a flared end.
8. The selective plug as claimed in claim 7 wherein the flared end
supports one or more collet fingers of a collet mounted at the
body.
9. The selective plug as claimed in claim 1 wherein the rotator
configuration includes a biasing arrangement.
10. The selective plug as claimed in claim 9 wherein biasing
arrangement is a spring.
11. A method for conducting borehole operations comprising:
determining where in a borehole an operation is desired; setting a
selective plug; and deploying the selective plug into the borehole.
Description
BACKGROUND
[0001] In the Drilling and completion industries it is often
desirable to affect tools or formations at a great distance from a
surface located facility such as a rig. One example of an operation
intended to affect a formation is a fracturing operation. In order
to perform such an operation, hydraulic pressure is built within a
tubing string until the pressure exceeds formation capability for
holding that pressure and fractures form in the formation. This
type of operation is most effective if done in small incremental
sections of a borehole for reasons related to control and
distribution of fractures to serve the ultimate purpose of the
borehole. Such purposes include hydrocarbon production, CO2
sequestration, etc.
[0002] In the art, fracturing discrete locations of the borehole
tends to require a number of tools that increase expense initially
and generally create other issues to be overcome after the
fracturing process is complete such as removal of the tools that
enabled the pressuring of a discrete location. Where multiple
fracturing locations are contemplated, generally a staged system
must be built and administered correctly for it to work. One such
system uses progressively larger seat diameters from the toe back
to surface and then progressively increasing diameter balls. While
the system works well, it is limited by the number of different
size balls that can be used. Tolerance is required in any system
and therefore limits the number of diameters that will be
functional even further.
[0003] Since fracturing and other operations where discrete
locations are desired to be isolated or accessed continue to become
more prevalent and ubiquitous, alternate systems for accessing and
manipulating the downhole environment is always well received.
SUMMARY
[0004] A selective plug including a body; and a rotator
configuration in operable communication with the body capable of
causing the plug to selectively pass a number of borehole
restrictions to reach and engage a target restriction.
[0005] A method for conducting borehole operations including
determining where in a borehole an operation is desired; setting a
selective plug; and deploying the selective plug into the
borehole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Referring now to the drawings wherein like elements are
numbered alike in the Figures:
[0007] FIG. 1 is a schematic cross sectional view of a selective
plug described herein;
[0008] FIG. 2 is a schematic cross sectional view of another
embodiment of a selective plug described herein;
[0009] FIG. 3 is a schematic cross sectional view of yet another
embodiment of a selective plug as described herein;
[0010] FIG. 4 is a perspective partial phantom view of the
embodiment of FIG. 3; and
[0011] FIG. 5 is another perspective cross sectional view of the
embodiment of FIG. 3.
DETAILED DESCRIPTION
[0012] Referring to FIG. 1, a selective plug 10 is illustrated. The
plug 10 is settable to pass through a number of restrictions (one
shown as 12) in a borehole. Generally the restriction 12 will
protrude radially inwardly from a casing 14 but the invention is
not limited to cased boreholes but rather is usable in any borehole
configuration where restrictions are employed. The plug itself
comprises a body 16 sized to be able to pass through restrictions
in the borehole in which the plug is intended to be employed. The
body supports a seal member 18 at an outside surface 20 thereof,
the seal member intended to provide a pressure tight interaction
with the target restriction 12. The degree of sealing required
depends upon the degree of pressure that is intended to be applied
to the borehole system, the higher the intended pressure the higher
the contact force of the seal member 18 with the restriction 12 and
hence the more robust the pressure seal.
[0013] The body 16 further includes openings 22 (two shown but more
may be disposed about the periphery of the body 16). The openings
22 allow for the through passage of rotationally secured keys 24.
The keys are interactive with the restrictions(s) 12 as a
rotational axis 26 of each key comes into proximity with the
restriction 12. As can be viewed in FIG. 1, one of the keys 24 is
illustrated in contact with the restriction 12. Each of the keys 24
includes a biasing arrangement 25 at the rotational axis 26 to
cause the key to move to a position where engagement with a next
restriction will occur. The other side of the key is in
communication with a ratchet housing 28 where a plurality of
ratchet teeth 30 are positioned. The keys and the ratchet housing
together form an incrementing configuration. It is to be
appreciated that a number of ratchet teeth are illustrated but that
in a commercial embodiment there may be many more. The number of
ratchet teeth must be enough to allow incremental movement of the
ratchet housing 28 through all of the restrictions that will be
passed through. In one embodiment, there will be at least as many
teeth as all the restrictions in a particular or a hypothetical
borehole. Either way the point is that with enough teeth 30 it is
possible to set the plug to pass as many restrictions as desired
even if the target restriction is the deepest one in the borehole.
This will be more clear when operation of the plug is
discussed.
[0014] Finally, the ratchet housing 28 includes a dampener 32
comprising in one embodiment, a fluid chamber 34 and a piston 36
bifurcating the fluid chamber 34. The piston includes a flow
passage 38 having a relatively restricted dimension through which
fluid may pass from one end of the piston to the other end of the
piston thereby moving the fluid in the fluid chamber 34 from one
side of the piston to the other during operation of the plug 10.
The function of the dampener 32 is to slow the reaction of the keys
24 when they rotate due to contact with a restriction 12. This
causes a pressure spike uphole of the plug 10 that can be detected
to verify that the plug 10 has encountered a restriction. Counting
the verification events then provides confidence that when the plug
does land without passing a restriction, it is the correct target
restriction. It is to be appreciated that although the dampener
provides for desirable functionality, it is not required for the
plug to operate with respect to its primary objective, which is to
selectively pass a number of restrictions and to not pass a target
restriction. The plug 10 will do so whether or not a pressure spike
is produced or received at a remote location.
[0015] In embodiments that do include the dampener 32 a variation
of its structure allows for easier setting of the plug 10 by
including a check valve 40, which provides a much greater flow area
for movement of the piston 36 in a setting direction than it does
for piston movement during operation of the plug 10.
[0016] Finally the plug 10 includes a selection indicator 42. An
operator uses the indicator to set the plug 10 to bypass a number
of restrictions that will cause the plug to set in the target
restriction.
[0017] Operation of the plug illustrated in FIG. 1 begins with the
setting of the number of restrictions that are to be passed in a
borehole. The ratchet housing 28 is moved within the body 16 to set
one or more of the keys 24 in a position between two of the teeth
30. Selecting a position means that a leading end 44 of ratchet
housing 28 is spaced a certain distance from an inside surface 46
of body 16. When the distance is absorbed by movement of the
ratchet housing 28 pursuant to the action of keys 24 while passing
restrictions 12, the ratchet housing 28 is physically prevented
from moving further and hence the keys are physically prevented
from rotating further. Whatever key 24 that is in contact with a
target restriction 12 at this time will prevent further advancement
of the plug 10 and the borehole is ready for pressurization to
whatever extent has been designed into the plug 10. The distance
between end 44 and surface 46 is slowly absorbed by the movement of
the ratchet housing 28 because as each key 24 engages a
restriction, a force is placed upon the key. Because the key is
allowed to move about a rotational axis 26 the force acting on the
key 24 from the restriction is transmitted through the key to
rotational axis 26. The rotational axis 26 changes the direction of
the force to apply it to one of the plurality of teeth 30 thereby
pushing the ratchet housing 28 toward surface 46. This action
continues until the angle of the key 24 has exhausted it force
providing potential through rotation. As will be appreciated from
the Figure, at least one other of the keys 24 is offset from the
first discussed key 24. This allows the second key 24 to engage the
next one of the plurality of teeth 30 when the first discussed one
of the plurality of teeth is still resting on a crown of the last
actuated one of the plurality of teeth. Following another
rotational change in key 24 position the first key will come off
the crest of the tooth it was resting on and drop into the next
trough between two of the plurality of teeth 30. From this position
the key is again positioned to have effect on the ratchet housing
28 at the next restriction 12. The number of keys that are being
used to move the ratchet housing 28 at a given restriction can be
as few as one or as many as is practicable in the space available
in the body 16 depending upon desires for particular applications.
The keys each return to the position where engagement with teeth
and restriction is possible via the biasing arrangement 25 such as
a torsion spring.
[0018] As noted above, the ratchet housing 28 is moved such that
end 44 moves away from surface 46 during setting of the plug 10. In
embodiments where dampener 32 is employed a specific embodiment of
the dampener 32 includes the check valve 40 noted above. Due to the
increased flow area that is gained through the check valve 40, an
operator moving the ratchet housing 28 for setting purposes will
not have to work as hard as he or she would if the check valve were
not present (which is certainly contemplated in some
embodiments).
[0019] In another embodiment of a selective plug 110, referring to
FIG. 2, the same ultimate goal of producing a plug that will bypass
a selected number of restrictions before remaining in one for some
period of time is accomplished. Similar to the foregoing embodiment
there are a number of restrictions 12 in a borehole that may be
cased or open providing there is a mechanism for providing
restrictions 12. In the embodiment of FIG. 2, a body 116 includes
one or more openings 122 (one shown) where in each of which is a
key 124 that is articulated to the body 116 at pivot 150. The key
further includes an articulated lever 152 that is configured to
engage one of a plurality of teeth 130. As illustrated there are
two keys 124a and 124b and two accompanying levers 152a and 152b.
These are spaced axially from one another to enable the counting
function of the plug 110. It is important to note that the one or
more keys that are included in the plug 110 are in one embodiment
arranged around the body 116. It is not intended that the reader
presume that because the illustrated keys 124 are axially arranged
that all of the possible keys 124 that may be incorporated in the
embodiment would be axially arranged. It is also not necessarily
required that there be axially spaced keys but rather that there be
a mechanism to hold the spring 158 while a key that has urged the
ratchet housing 128 toward the right hand side of the drawing in
FIG. 2 moves to a reset position, having emerged from the
compression of the restriction 12. This will be further described
hereunder. The body 116 further includes one or more dogs 154 that
are extendible radially outwardly of the body 116 under
circumstances of actuation of the plug 110.
[0020] The teeth 130 are positioned upon a ratchet housing 128. The
ratchet housing further includes a one or more dog supports 156
thereon that at a particular position of the ratchet housing 128
will support the dogs 154 in a radially outwardly extended
position. This position is achieved when the ratchet housing 128 is
fully stroked within the body 116 by having passed through the
selected number of restrictions 12. To ensure that the ratchet
housing 128 moves by only one tooth increment per restriction
passed, a biasing arrangement 158 is included such as a compression
spring that bears against one end of the body 116 and one end of
the ratchet housing 128 as illustrated. These components make up an
incrementing configuration for this embodiment.
[0021] Finally, at an uphole end of the ratchet housing, a wiper
160 is disposed to enable the plug 110 to be moved through the
borehole using fluid pressure applied from uphole and a selection
indicator 142 to assist the operator in setting the plug 110 to
bypass a denied number of restrictions.
[0022] In operation, the plug 110 is initially manually set at a
surface location by an operator. The ratchet housing 128 is
positioned relative to the body 116 such that a selected number of
teeth 130 are required to be ratcheted through before the dog
support 156 moves to support the dogs 154. The number of teeth is
the same as the number of restrictions through which the plug is
being set to pass before it is to hold its position to support
another operation such as a fluid pressure build up uphole of the
plug 110 for tool actuation or fracturing, etc. Because the biasing
arrangement 158 applies a force on the ratchet housing 128 in a
direction to the left in the drawing FIG. 2, the lever 152 is
caught in a trough of the teeth 130. The lever is hence urged by
the tooth it is engaged with against the key 124a causing the key
to pivot radially outwardly of the body 116. The radial dimension
of the one or more keys 124 is greater than the restrictions that
the plug 110 will encounter during its trip downhole. The key(s)
124 will thus land on the restrictions 12 that it/they arrive at
and be urged radially inwardly by the restriction. The radially
inward urging causes the lever 152a to apply a force to the tooth
with which it is engaged overcoming the oppositely acting force
from the biasing arrangement 158 and thereby moving the ratchet
housing 128 toward end 162 of body 116. The movement is incremental
but is for a sufficient distance to allow lever 152b to engaged its
next-in-line tooth 130 to hold the new position that the key 124a
and lever 152a passing through the restriction have achieved for
the ratchet housing 128. Because of the positioning of the keys
124a and 124b or the length of levers 152a and 152b, the keys 124a
and 124b and 152a and 152b together act as an escapement to
facilitate maintenance of the ratchet housing 128 in its
incremental position. The key 124a will move radially outwardly
again based upon a torsion spring disposed at pivot 150 or similar
making it ready to engage the next restriction 12. The same is true
for key 124b. The described sequence continues until the dog
support 156 arrives at the dogs 154 and supports them. The next
restriction through which the plug 110 is moved will encounter the
supported dogs 154. Since the dogs 154 do not yield to the
restriction 12, the plug 110 will maintain its position in the
target restriction to allow whatever fluid pressure holding
operation is desired.
[0023] In yet another embodiment, referring to FIGS. 3-5, a
selective plug 210 having the same capabilities as the plugs
described hereinbefore is illustrated. This embodiment includes a
body 216 having a flared end 264. The flared end is in one
embodiment includes ramped surfaces 266 and 268. Surface 266
assists in directing the plug 210 trough a restriction by avoiding
a sharp shoulder that otherwise might catch on a portion of the
restriction 12 while surface 268 cooperates with a collet 270 in
the operation of the plug 210 as will be further elucidated
hereunder. A wiper 260 is positioned at an opposite end of the body
216 from the flared end 264.
[0024] Upon the body 216 is mounted a key 224 that is interactive
with a rotator 276 in operation of the plug 210. The key 224
further provides a seat 274 for a biasing arrangement 258. The
biasing arrangement will in one embodiment comprise a compression
spring such as a coil spring as shown. The biasing arrangement 258
acts between the seat 274 and the collet 270, urging the two apart
from one another.
[0025] The rotator 276 is disposed between the collet 270 and the
body 216 and provides, in one embodiment, the selectivity in target
restriction in cooperation with key 224. A selection indicator 242
is also provided for purposes identical to those described
above.
[0026] Before making reference to FIGS. 4 and 5 to illustrate the
rotator 276 and the key 224 interaction, it is helpful to
understand the high level operation of the plug. The plug 210 will
be set by positioning the rotator 276 relative to the key 224 and
then introduced to the borehole. When the plug 210 encounters a
restriction 12, the collet 270 lands on the restriction 12 and a
load is transferred into the collet 270. The load provides a
greater force than does the biasing arrangement 258 and so the
collet moves relative to the body 216 allowing the flared end 264
of the body 216 to move through the restriction and at the same
time unsupport one or more collet fingers 278. Once the fingers 278
are unsupported they will flex radially inwardly causing the
outside diameter of the collet 270 at fingers 278 to become smaller
than the restriction and therefore move therethrough. At each
restriction this movement is possible thereby allowing the plug 210
to pass through an unlimited number of restrictions. To limit the
number of restrictions through which the plug 210 will pass and
thereby select a target restriction upon which the plug 210 will
seat for a period of time, the rotator 276 and key 224 are included
in the plug 210.
[0027] Referring now to FIGS. 4 and 5, understanding of the rotator
276 and key 224 and how they interact to produce an incrementing
configuration will improve. In FIG. 4, the collet 270 has been
illustrated in phantom to allow a viewer to see the rotator 276.
Rotator 276 is, in one embodiment, configured with a J-slot 280 on
an outside dimension surface thereof and a plurality of step
profile teeth 282 on an inside dimension surface thereof (FIG. 5).
The Jslot 280 interacts with a lug 284 attached to the collet 270.
Each time the collet 270 is urged against the bias of biasing
arrangement 258, the lug 284 contacts an angled surface 286 of the
Jslot 280 and causes the rotator 276 to rotate a small degree. Each
time the collet 270 moves back toward the flared end 264, the lug
will contact another angled surface 288 and the rotator will rotate
another small increment. Based upon the position of the step
profile 282 relative to the key 224, a selected number of
restrictions 12 will be passed before the key 224 engages a step of
the step profile 282 and prevents the collet 270 from cycling. Upon
this condition, the next restriction encountered by the plug 210
will not be passed but the plug 210 will seat thereon and whatever
operation was intended may be carried out.
[0028] Finally it is to be understood while one or more embodiments
have been shown and described, modifications and substitutions may
be made thereto without departing from the spirit and scope of the
invention. Accordingly, it is to be understood that the present
invention has been described by way of illustrations and not
limitation.
* * * * *