U.S. patent application number 10/290593 was filed with the patent office on 2003-06-19 for drill bit stabilizer.
This patent application is currently assigned to Rotary Drilling Technology, LLC. Invention is credited to Harvey, Peter R., Krase, Steve J., Woods, Michael J..
Application Number | 20030111270 10/290593 |
Document ID | / |
Family ID | 24122896 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030111270 |
Kind Code |
A1 |
Harvey, Peter R. ; et
al. |
June 19, 2003 |
Drill bit stabilizer
Abstract
A stabilizer for a drill string and drill bit is mounted behind
the drill bit in the drilling assembly. The stabilizer comprises a
tubular body having one or more stabilizer blades mounted thereon.
The stabilizer blades extend radially outwardly from the stabilizer
body. In a first position, the stabilizer blades are in vertical
axial alignment behind the drill bit. Drill string pressure is
utilized to release a locking mechanism permitting relative
rotation between the stabilizer blades and the stabilizer body
thereby rotating the stabilizer blades to a second position
providing stabilization for the drill string and drill bit.
Inventors: |
Harvey, Peter R.; (San Jose,
CA) ; Woods, Michael J.; (Houston, TX) ;
Krase, Steve J.; (Spring, TX) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
Rotary Drilling Technology,
LLC
|
Family ID: |
24122896 |
Appl. No.: |
10/290593 |
Filed: |
November 8, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10290593 |
Nov 8, 2002 |
|
|
|
09532725 |
Mar 22, 2000 |
|
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Current U.S.
Class: |
175/325.5 ;
175/399; 175/408 |
Current CPC
Class: |
E21B 23/04 20130101;
E21B 17/1014 20130101; E21B 17/1064 20130101; E21B 47/01
20130101 |
Class at
Publication: |
175/325.5 ;
175/408; 175/399 |
International
Class: |
E21B 010/00; E21B
017/10 |
Claims
1. A drill bit stabilizer, comprising: a) a stabilizer body having
an axial passage extending therethrough, said stabilizer body
including a pin connector on one end and a box connecter on the
other end for connecting said stabilizer body in a drill string; b)
at least one stabilizer blade mounted about said stabilizer body;
c) an actuator housing mounted in said axial passage of said
stabilizer body; d) piston means carried by said housing for
coupling said stabilizer blade with said stabilizer body; and e)
conduit means providing fluid communication between said piston
means and said axial passage of said stabilizer body.
2. The apparatus of claim 1 wherein said piston means comprises a
piston rod having pins mounted on the distal ends thereof, and
wherein said piston rod and said pins are in a transverse bore
extending through said actuator housing and said stabilizer
body.
3. The apparatus of claim 1 including means pivotally mounted on
the periphery of said stabilizer blade for engaging the inner wall
of a borehole upon rotation of said stabilizer body.
4. The apparatus of claim 3 wherein said pivotal means comprise a
brake shoe mounted in a recess formed on the peripheral edge of
said stabilizer blade.
5. The apparatus of 4 wherein said brake shoe is pivotally secured
in said recess and further including biase means providing an
outward force against said brake shoe.
6. The apparatus of claim 4 wherein said brake shoe includes an
axial elongate slot and a post extending through said slot and
secured in said recess for limiting the outward radial movement of
said brake shoe.
7. The apparatus of claim 1 including means for rotating said
stabilizer body relative to said stabilizer blade from a first
position to a second position.
8. The apparatus of claim 1 including at least three stabilizer
blades vertically aligned on said stabilizer body.
9. The apparatus of claim 8 wherein one of said stabilizer blades
is integrally formed with said stabilizer body.
10. The apparatus of claim 8 wherein said stabilizer blades are
rotated from a first position to a second position for providing
full gauge stabilization.
Description
BACKGROUND OF THE DISCLOSURE
[0001] The present invention relates generally to drill bit
stabilizers for drilling subterranean formations, particularly, to
a stabilizer for providing full gauge stabilization for a drill
bit.
[0002] When drilling a well bore, for example drilling an oil and
gas well, many problems are encountered. A substantial portion of
such drilling problems relate to drill bit and drill string
instability which places high stress on drilling equipment, not
only on drill bits but also on downhole tools and the drill string.
Drill bit instability problems are particularly inherent with
bi-center bit designs because of an inability to provide full gauge
stabilization near the bit. Bi-center bits drill a larger hole than
the pass through diameter of the casing, therefore conventional
stabilizers cannot pass through the casing with the bi-center bit.
For this reason, bi-center bits are typically run with no
stabilization within approximately the bottom 50 feet of the
borehole assembly. Bi-center drill bits, designed to simultaneously
drill and under-ream a wellbore, are particularly prone to poor
directional control, and often produce smaller than expected hole
diameter because of the lack of stabilization. While bi-center bits
have been available for more than twenty years, they have seen
limited use because of the inherent problems associated with
bi-center drill bits. New technologies however have led to the
design of new bi-center bits which perform comparable to
conventional drill bits.
[0003] Bi-center bits are now in greater demand for use in various
drilling applications, including directional drilling in deep water
where using a steerable motor assembly is necessary. Current
bi-center bit designs focus on minimizing bi-center force
imbalance. While advances have been made to overcome the inherent
instability of the bi-center bit, it has yet to realize its full
potential as a reliable alternative to conventional
undereaming.
[0004] It is therefore an object of the present invention to
provide a stabilizer for providing drill bit directional control
and engagement with the borehole wall.
[0005] It is another object of the present invention to provide a
bi-center drill bit stabilizer mounted behind the bi-center bit. In
a first position, the stabilizer blade of the invention is
positioned axially aligned with the reamer wing of the bi-center
bit.
[0006] It is yet another object of the present invention to provide
a drill bit stabilizer which may rotationally deploy a stabilizer
blade from a first position to a second position opposite the first
position.
[0007] It is still another object of the invention to provide a
stabilizer apparatus providing full gauge stabilization.
[0008] It is a further object of the invention to provide full
gauge stabilization for a drilling apparatus in a borehole.
SUMMARY OF THE INVENTION
[0009] The present invention provides a stabilizer for a drill bit.
The stabilizer is mounted behind the drill bit in the drilling
assembly. The stabilizer comprises a tubular body having one or
more stabilizer blades mounted thereon. The stabilizer blades
extend radially outwardly from the stabilizer body. In a first
position, the stabilizer blades are in axial alignment behind the
drill bit. Drill string pressure is utilized to release a locking
mechanism permitting relative rotation between the stabilizer
blades and the stabilizer body thereby rotating the stabilizer
blades to a second position providing stabilization for the drill
bit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the above recited features,
advantages and objects of the present invention are attained can be
understood in detail, a more particular description of the
invention briefly summarized above, may be had by reference to the
embodiments thereof which are illustrated in the appended
drawings.
[0011] It is noted, however, that the appended drawings illustrate
only typical embodiments of this invention and are therefore not to
be considered limiting of its scope, for the invention may admit to
other equally effective embodiments.
[0012] FIG. 1 is a side view of the stabilizer of the
invention;
[0013] FIG. 2 is a section view of the stabilizer of the invention
depicting the stabilizer with a single stabilizer blade;
[0014] FIG. 3 is a section view of the stabilizer of the invention
taken along line 3-3 of FIG. 2;
[0015] FIG. 4 is a side view of the stabilizer of the invention
illustrating the stabilizer of the invention mounted behind a
bi-center bit being lowered in a borehole;
[0016] FIG. 5 is a side view of the stabilizer of the invention
illustrating the location of the stabilizer in a second position
providing drill bit stabilization;
[0017] FIG. 6 is a side view of an alternate embodiment of the
stabilizer of the invention;
[0018] FIG. 7 is a section view of the stabilizer of the invention
shown in FIG. 6;
[0019] FIG. 8 a is section view of the stabilizer of the invention
taken along line 8-8 of FIG. 7;
[0020] FIG. 9 is a section view of the stabilizer of the invention
taken along line 9-9 of FIG. 7; and
[0021] FIG. 10 is a side view of the stabilizer of the invention
depicting the stabilizer blades in a full gauge position.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0022] Referring first to FIG. 1, the stabilizer of the invention
is generally identified by the reference numeral 10. The stabilizer
10 of the invention includes a substantially tubular body 12,
manufactured from steel or other hard metal material. A threaded
pin 14 is provided at one end of the stabilizer body 12 for
connection to a drill string 13 located in a borehole 15, as best
shown in FIG. 4. The opposite end of the stabilizer body 12 is
provided with a threaded coupling 16 for connection to a drill bit
17. A stabilizer blade 18 integrally formed on a cylindrical collar
20 is mounted on the stabilizer body 12. The blade 18 extends
radially outward from the collar 20 which includes an axial
passageway for receiving the pin end of the stabilizer body 12
therethrough. The collar 20 is positioned about the central portion
and rests against the shoulder 21 of the stabilizer body 12 as best
shown in FIG. 2.
[0023] Referring still to FIG. 2, the circumferential shoulder 21
is formed on the external surface of the stabilizer body 12. The
shoulder 21 provides a stop or support surface for engagement with
the lower end of the collar 20. A sleeve 22 secured about the upper
portion of the stabilizer body 12 engages the upper end of the
collar 20 for retaining the collar 20 on the stabilizer body 12.
The sleeve 22 is secured to the stabilizer body by a lock key 24
which extends through an opening in the side of the sleeve 22 and
is received in a recess formed in the stabilizer body 12. The key
24 is fixedly secured in position by a bolt 26 or similar
connector.
[0024] The collar 20 and stabilizer blade 18 are retained on the
stabilizer body 12 between the shoulder 21 and the sleeve 22 which
prevent relative axial movement between the stabilizer body 12 and
the collar 20. Relative rotational movement, however, between the
stabilizer body 12 and the collar 12 is permitted.
[0025] Referring now to FIGS. 2 and 3, an axial passage 28 extends
through the stabilizer body 12. An actuator piston housing 32 is
located within the passage 28 as best shown in FIG. 2. The piston
housing 32 is cylindrical in shape having an external diameter
substantially equal to the diameter of the passage 28 below a
circumferential shoulder 30 formed on the internal surface of the
stabilizer body 12. The piston housing 32 is positioned within the
passage 28 so that its planar end surface 33 is in facing contact
with the internal circumferential shoulder 30. O-rings 35 received
in circumferential recesses formed adjacent to the upper and lower
ends of the piston housing 32 form a seal between the periphery of
the piston housing 32 and the internal surface of the stabilizer
body 12 defined by the passage 28. A pair of passages 37 extend
through the piston housing 32 permitting drilling fluid to pass
therethrough.
[0026] The piston housing 32 includes a transverse passageway 34
proximate to the end surface 33 of the piston housing 32. The
passageway 34 is sized to receive a piston rod 36. Load pins 38 and
40 are mounted on the ends of the piston rod 36. The pins 38 and 40
are received in recesses 39 and 41, respectively, formed in the
stabilizer body 12. Shoulder screws 42 extend through the pins 38
and 40 and secure the pins 38 and 40 to the distal ends of the
piston rod 36.
[0027] Referring now specifically to FIG. 3, the pin 38 is provided
with a neck portion 44 which depends from the bottom surface 63 of
the pin 38. A spring 46 is journalled about the neck 44 of the pin
38. The spring 46 is retained in the recess 39 between the bottom
surface 63 of the pin 38 and an inwardly extending circumferential
shoulder 48 which defines the bottom of the recess 39. The spring
46 exerts an outward force against the bottom of the pin 38 so that
the leading edge of the pin 38 projects beyond the periphery of the
piston housing 32 into a circumferentially extending recess 45
formed in the inner wall of the collar 20. One side of the pin 38
includes a planar surface 53 offset from and parallel to the cental
axis of the load pin 38. In the initial or start position shown in
FIG. 3, the surface 53 of the pin 38 is in facing contact with a
wall 47 defining one end of the recess 45. The opposite end of the
recess 45 is defined by a wall 49 diametrically opposite the wall
47.
[0028] The outwardly biasing force of the spring 46 is aided by the
borehole pressure which is transmitted to the piston rod 36 through
a fluid conduit 55 formed in the body of the piston housing 32. The
conduit 55 is in fluid communication with a passage 57 extending
through the wall of the stabilizer body 12 and is open to the
borehole 15. Thus, borehole pressure is transmitted to a fluid
chamber 61 about a portion of the piston rod 36 via the passage 57
and conduit 55 adding redundancy to the biasing force applied to
the pin 38 by the spring 46.
[0029] Referring still to FIG. 3, a brake shoe 50 is pivotally
mounted on the periphery of the blade 18. The shoe 50 is secured in
a recess 51 formed in the blade 18 by a pivot pin 52. Radial
movement of the shoe 50 is limited by a pin 54 mounted in the blade
recess 51 and extending through a slot 56 formed through the shoe
18. A spring 58 retained in bore 60 formed in the blade 18, urges
the shoe 50 outwardly as shown in FIG. 3. As the stabilizer 10
rotates in the borehole 15 with the drill bit 17, the outward force
applied by the spring 58 and centrifugal force developed by the
rotating stabilizer 10 forces the shoe 50 radially outwardly about
the pivot pin 52 into engagement with the wall of the borehole
15.
[0030] Referring now to FIG. 4, the stabilizer 10 of the invention
is shown used in combination with a bi-center bit 17. It will be
observed that unlike most drilling tools, the center axis of the
bit 17 and stabilizer 10 while being lowered or tripped in the
casing or borehole 15 is not the same as the borehole axis. The
stabilizer 10 is mounted behind the bit 17 so that the blade 18 is
above and aligned with the reamer wing 62 of the bit 17. It will
further be observed that the maximum diameter of the bi-center bit
17 is greater than the diameter of the pilot bit 64 mounted on the
lower or face end of the bit 17. In this configuration, the
stabilizer 10 and bit 17 offset to one side of the casing or
borehole 15 when tripped in so that they fit inside the borehole 15
as shown in FIG. 4. Once drilling commences, the pilot bit 64
centralizes the drill string assembly, including the stabilizer 10
and the drill bit 17, thereby causing the reamer wing 62 and the
stabilizer blade 18 to rotate about the borehole axis and thus
increase the diameter of the borehole 15 below the casing as shown
in FIG. 5.
[0031] As drilling begins, the stabilizer blade 18 is oriented in
the same direction as the reamer wing 62 as shown in FIG. 4. When
the drill string pressure in the passage 28 exceeds a predetermined
value, a burst plate 66 covering the lower end of a second conduit
68 provided in the piston housing 32 bursts, thereby providing a
fluid passage to the fluid chamber 69 formed about a portion of the
piston rod 36 so that the fluid pressure in the passage 28 is
applied against the piston rod 36.
[0032] The drill string fluid pressure in the passage 28 is greater
than the borehole pressure. Thus, the higher pressure in the
chamber 69 applied against the piston rod 36 forces the piston rod
36 to move to the left in the view shown in FIG. 3. Retraction of
the pin 38 into the recess 39 compresses the spring 46 and
disengages the piston surface 53 from the wall 47 permitting the
stabilizer body 12 to rotate relative to the stabilizer blade 18
and collar 20. Rotation of the stabilizer body 12 allows the pin 40
to moive to the position of the pin 38 shown in FIG. 3 into
engaging contact with the wall 47 of the recess 45. The stabilizer
body 12 and the bit 17 connected thereto rotate 180.degree. so that
the reamer wing 62 is opposite the stabilizer blade 18 as best
shown in FIG. 5.
[0033] In the configuration shown in FIG. 5, the stabilizer blade
18 and the reamer wing 62 project in opposite directions in the
borehole 15. When drilling is completed and circulation is stopped,
fluid pressure in the chambers 61 and 69 on both sides of the
piston rod 36 is equalized permitting the spring 46 to force the
pin 38 outward and thereby disengage the pin 40 from the wall 47 of
the recess 45. The stabilizer body 12 is then rotated to its
original position locating the stabilizer blade 18 behind the
reamer wing 62 so that the bit 17 may be removed from the borehole
15.
[0034] Referring now to FIGS. 6-10, an alternate embodiment of the
invention providing full gauge borehole stabilization is disclosed.
The full gauge stabilizer is generally identified by the reference
numeral 100. The stabilizer 100 is substantially similar to the
stabilizer 10 described above. Therefore, the same reference
numerals are used to identify like components.
[0035] The stabilizer 100 provides full gauge stabilization behind
the drill bit 17. That is, the stabilizer 100 contacts the borehole
wall at three point approximately 120.degree. apart. The stabilizer
100 includes a stabilizer body 102 substantially similar to the
stabilizer body 12 shown in FIG. 2, but longer in length for
supporting three stabilizer blades stacked one above the other.
Beginning at the lower end of the stabilizer body 102, the
lowermost stabilizer blade 104 is integrally formed with the
stabilizer body 102. It extends outwardly from the stabilizer body
102 in the same manner as the stabilizer blades 18 but does not
include a brake shoe 50. The stabilizer blade 104 rotates with the
stabilizer body 102 as will be described in greater detail
hereinafter.
[0036] Referring now to FIG. 7, a pair of stabilizer blade
assemblies 106 and 108 are mounted on the stabilizer body 102 in
vertical alignment above the stabilizer blade 104. The blade
assemblies 106 and 108 are substantially identical to the blade
assembly of the embodiment of the invention shown in FIGS. 1-5 and
described herein. Thrust bearings 1 10 and 1 12 are provided to
reduce binding between the stabilizer blade assemblies 106 and 108
and the stabilizer body 102.
[0037] The stabilizer 100 is tripped in the borehole 15 in the same
manner described above. The stabilizer blades are aligned above the
reamer wing 62 of the bi-center bit 17 permitting the bi-center bit
and stabilizer 100 to move to one side of the borehole 15. When the
bottom of the borehole 15 is reached and the drill string is
rotated, the pilot bit 64 centralizes the assembly so that the
reamer wing 62 rotates about the central axis of the borehole 15.
The center of the bi-center bit 17 thus becomes the center of the
borehole 15 allowing the reamer wing 62 and pilot bit 64 to enlarge
the borehole 15 to the desired diameter.
[0038] Referring again to FIG. 7, it will be observed that the
fluid conduits 55 and 68 of the piston housings 32 of the blade
assemblies 106 and 108 are vertically aligned so that fluid
pressure from the borehole 15 and the lower portion of the axial
passage 28 extending through the stabilizer body 102 is
communicated to the piston rod 36. In the manner previously
described, upon reaching a predetermined fluid pressure value in
the passage 28, the burst plate 66 bursts and the drill string
pressure is communicated to piston rods 36 of the stabilizer
assemblies 106 and 108. The increase in fluid pressure actuates the
piston assemblies forcing the pin 38 in the stabilizer assembly 106
to retract and disengage from the wall 112 of a circumferentially
extending recess formed in the collar 20, thereby permitting the
drill bit 17, the stabilizer body 102, the stabilizer blade 104 and
the stabilizer assembly 108 to rotate relative to the stabilizer
assembly 106. Assuming that the blade 18 of the stabilizer assembly
106, in the orientation shown in FIG. 7, defines the 0.degree.
point about the borehole 15, the stabilizer assembly 108 rotates
120.degree. about the central axis of the borehole 15. The
stabilizer body 102 and blade 104 rotate 240.degree. about the
central axis of the borehole 15. The relative rotation between the
components is limited by the engagement of the pins 40 against the
wall 114 of a circumferential recess 116 formed in the collar 20 of
the stabilizer assembly 106 and the wall 118 of a circumferential
recess 120 formed in the collar 20 of the stabilizer assembly 108.
The position of the stabilizer blade 104 and the blade 18 of the
stabilizer assembly 108 is shown in phantom in FIG. 9. Thus, the
stabilizer blades 18 and 104 contact the borehole wall at three
points about the central axis of the borehole 15 approximately
120.degree. apart, thereby providing full gauge stabilization of
the drill string behind the bit 17.
[0039] While several preferred embodiments of the invention have
been shown and described, other and further embodiments of the
invention may be devised without departing from the basic scope
thereof, and the scope thereof is determined by the claims which
follow.
* * * * *