U.S. patent application number 14/402014 was filed with the patent office on 2015-06-18 for eccentric adjustment coupling for mud motors.
The applicant listed for this patent is Smith International, Inc.. Invention is credited to Samuel Collette, William Murray.
Application Number | 20150167390 14/402014 |
Document ID | / |
Family ID | 49584357 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150167390 |
Kind Code |
A1 |
Murray; William ; et
al. |
June 18, 2015 |
Eccentric Adjustment Coupling For Mud Motors
Abstract
According to one aspect, there is provided a drilling motor
assembly having a power section configured to generate torque, a
transmission section coupled to the power section, and a bearing
section coupled to the transmission section, the bearing section
configured to couple to a drill bit. The transmission section
includes a housing assembly having a bore formed therethrough, the
housing assembly having a central axis defined therethrough and the
bore having a central axis defined therethrough, in which the
central axis of the bore is radially offset from the central axis
of the housing assembly.
Inventors: |
Murray; William; (Tomball,
TX) ; Collette; Samuel; (Conroe, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Smith International, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
49584357 |
Appl. No.: |
14/402014 |
Filed: |
May 17, 2013 |
PCT Filed: |
May 17, 2013 |
PCT NO: |
PCT/US2013/041696 |
371 Date: |
November 18, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61648867 |
May 18, 2012 |
|
|
|
Current U.S.
Class: |
175/57 ;
175/107 |
Current CPC
Class: |
E21B 7/067 20130101;
E21B 4/02 20130101 |
International
Class: |
E21B 4/02 20060101
E21B004/02 |
Claims
1. A drilling motor assembly, comprising: a power section
configured to generate torque; a transmission section coupled to
the power section, comprising: a housing assembly comprising a bore
formed therethrough, the housing assembly having a central axis
defined therethrough and the bore having a central axis defined
therethrough, wherein the central axis of the bore is radially
offset from the central axis of the housing assembly; and a bearing
section coupled to the transmission section, the bearing section
configured to couple to a drill bit.
2. The assembly of claim 1, wherein the transmission section
comprises a transmission shaft disposed within the bore of the
housing assembly.
3. The assembly of claim 2, wherein the radial offset between the
central axis of the bore and the central axis of the housing
assembly provides clearance between the transmission shaft and an
internal surface of the housing assembly.
4. The assembly of claim 1, wherein the radial offset between the
central axis of the bore and the central axis of the housing
assembly is up to 5 mm.
5. The assembly of claim 1, wherein a cross-section of the housing
assembly comprises a variable wall thickness.
6. (canceled)
7. The assembly of claim 2, wherein a ratio between the diameter of
the transmission shaft and the diameter of the bore formed through
the housing assembly is 1:1.314.
8. (canceled)
9. (canceled)
10. A drilling motor assembly, comprising: a power section
configured to generate torque; a transmission section coupled to
the power section, comprising: an adjustable housing assembly
comprising a first sub coupled to a second sub and a bore formed
therethrough, the first sub having a first central axis defined
therethrough, the second sub having a second central axis defined
therethrough, wherein the bore formed through the adjustable
housing assembly comprises a first bore and a second bore, wherein
the first bore is formed through the first sub and the second bore
is formed through the second sub, the first bore having a first
central axis defined therethrough and the second bore having a
second central axis defined therethrough, wherein the first central
axis of the first sub is radially offset from the first central
axis of the first bore, and wherein the second central axis of the
second sub is radially offset from the second central axis of the
second bore; and a bearing section coupled to the transmission
section, the bearing section configured to couple to a drill
bit.
11. The assembly of claim 10, wherein the adjustable housing
assembly is configured to adjustably bend such that an offset angle
is formed between the first central axis of the first sub and the
second central axis of the second sub.
12. The assembly of claim 10, wherein the adjustable housing
assembly is configured to adjustably bend such that an offset angle
of up to 3 degrees is formed between the first central axis of the
first sub and the second central axis of the second sub.
13. The assembly of claim 10, wherein the transmission section
comprises a transmission shaft disposed within the bore of the
adjustable housing assembly.
14. (canceled)
15. The assembly of claim 13, wherein the radial offset between the
central axis of the bore and the central axis of the adjustable
housing assembly provides clearance between the transmission shaft
and an internal surface of the adjustable housing assembly when the
adjustable housing assembly is bent such that an offset angle is
formed between the first central axis of the first sub and the
second central axis of the second sub.
16. (canceled)
17. The assembly of claim 13, wherein a ratio between the the
diameter of the transmission shaft and outer diameter of the
adjustable housing assembly is 1:2.313.
18. The assembly of claim 13, wherein a ratio between the diameter
of the transmission shaft and the diameter of the bore formed
through the adjustable housing assembly is 1:1.314.
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. A method of using a drilling motor assembly, the method
comprising: disposing the drilling motor assembly having a power
section, a transmission section, and a bearing section downhole;
and transmitting torque from the power section to the bearing
section through the transmission section, wherein the transmission
section comprises an adjustable housing assembly having a central
axis defined therethrough and a bore formed therethrough, the bore
having a central axis defined therethrough, wherein the central
axis of the bore is radially offset from the central axis of the
adjustable housing assembly.
30. The method of claim 29, wherein the transmission section
comprises a transmission shaft disposed within the bore of the
housing assembly.
31. The method of claim 30, wherein the radial offset between the
central axis of the bore and the central axis of the housing
assembly provides clearance between the transmission shaft and an
internal surface of the housing assembly.
32. (canceled)
33. The method of claim 30, wherein a ratio between the diameter of
the transmission shaft and the outer diameter of the adjustable
housing assembly is 1:2.313.
34. The method of claim 30, wherein a ratio between the diameter of
the transmission shaft and the diameter of the bore formed through
the adjustable housing assembly is 1:1.314.
35. The method of claim 29, wherein the adjustable housing assembly
comprises a first sub coupled to a second sub and a bore formed
therethrough, the first sub having a first central axis defined
therethrough and the second sub having a second central axis
defined therethrough.
36. The method of claim 35, wherein the adjustable housing assembly
is configured to adjustably bend such that an offset angle of up to
3 degrees is formed between the first central axis of the first sub
and the second central axis of the second sub.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] Embodiments disclosed herein relate generally to drilling
motors having a transmission section for transmitting torque from a
power section to a bearing section. More specifically, the
embodiments disclosed herein relate to a transmission section for
drilling motors used in the oil and gas industry for drilling
boreholes, particularly in applications requiring the transfer of
large torque across the transmission section.
[0003] 2. Background Art
[0004] A drilling motor, also known as a mud motor, is a tool that
is assembled on a drilling string that uses hydraulic force to turn
a drill bit by pumping drilling fluid or air through the center of
the drilling motor. The drilling motor includes three major
sections: a power section, a transmission section, and a bearing
section. The power section is the section of a drilling motor that
generates power by pumping fluid or air through a pump, such as a
progressive cavity pump. This pump causes a rotation of the
internal components, while the external components stay stationary,
but the internal components could instead stay stationary while the
external components rotate. The transmission section is the section
of the drilling motor that translates the torque of the eccentric
motion generated by the power section into the concentric motion
that is used to drive the drill bit. The bearing section is the
section of a drilling motor that handles all of the radial and
axial loads produced by drilling operations. Drilling motors are
designed such that a bent sub can be installed across the
transmission section to be used to drill curved wells. An
adjustable bent housing assembly is commonly used in lieu of a bent
sub and allows a user to adjust the bend angle of the drilling
motor while on the rig floor. Both methods of bending the motor are
used in conjunction with a measurement while drilling tool in order
to control the direction and inclination of a drill bit. This
allows the operator to control the exact location and path of a
well bore.
[0005] Referring to FIG. 1, a cross-sectional view of a
conventional transmission section of a drilling motor is shown. As
shown, the transmission section includes an adjustable bent housing
assembly 100 having a central axis 150 defined therethrough.
Further, the adjustable bent housing assembly 100 has a bore 104
formed therethrough and a transmission shaft 110 disposed within
the bore 104 of the adjustable bent housing assembly 100. The
transmission shaft 110 may be used to transmit torque generated
from a power section of the drilling motor to a bearing section of
the drilling motor. As shown, the bore 104 is a concentric bore
that is formed through a center of the adjustable bent housing
assembly 100. As such, a central axis (not shown) of the bore 104
is collinear with the central axis 150 of the adjustable bent
housing assembly 100. Furthermore, as shown, insufficient clearance
and potential interference exists between the transmission shaft
110 and an inner surface 106 of the adjustable bent housing
assembly 100.
SUMMARY
[0006] According to one aspect, there is provided a drilling motor
assembly having a power section configured to generate torque, a
transmission section coupled to the power section, and a bearing
section coupled to the transmission section, the bearing section
configured to couple to a drill bit. The transmission section
includes a housing assembly having a bore formed therethrough, the
housing assembly having a central axis defined therethrough and the
bore having a central axis defined therethrough, in which the
central axis of the bore is radially offset from the central axis
of the housing assembly.
[0007] According to another aspect, there is provided a drilling
motor assembly having a power section configured to generate
torque, a transmission section coupled to the power section, and a
bearing section coupled to the transmission section, the bearing
section configured to couple to a drill bit. The transmission
section includes an adjustable housing assembly having a first sub
coupled to a second sub and a bore formed therethrough, the first
sub having a first central axis defined therethrough, the second
sub having a second central axis defined therethrough. The bore
formed through the adjustable housing assembly includes a first
bore and a second bore, in which the first bore is formed through
the first sub and the second bore is formed through the second sub,
the first bore having a first central axis defined therethrough and
the second bore having a second central axis defined therethrough.
The first central axis of the first sub is radially offset from the
first central axis of the first bore, in which the second central
axis of the second sub is radially offset from the second central
axis of the second bore.
[0008] According to another aspect, there is provided a method of
manufacturing a drilling motor assembly, the method including
forming a bore through an adjustable housing assembly, the
adjustable housing assembly having a first sub coupled to a second
sub and a bore foamed therethrough, the first sub having a first
central axis defined therethrough and the second sub having a
second central axis defined therethrough. The bore formed through
the adjustable housing assembly includes a first bore and a second
bore, in which the first bore is formed through the first sub and
the second bore is formed through the second sub, the first bore
having a first central axis defined therethrough and the second
bore having a second central axis defined therethrough. The first
central axis of the first sub is radially offset from the first
central axis of the first bore, in which the second central axis of
the second sub is radially offset from the second central axis of
the second bore.
[0009] According to another aspect, there is provided a method of
using a drilling motor assembly, the method including disposing the
drilling motor assembly having a power section, a transmission
section, and a bearing section downhole and transmitting torque
from the power section to the bearing section through the
transmission section. The transmission section includes an
adjustable housing assembly having a central axis defined
therethrough and a bore formed therethrough, the bore having a
central axis defined therethrough. The central axis of the bore is
radially offset from the central axis of the adjustable housing
assembly.
[0010] Other aspects and advantages of the invention will be
apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 shows a cross-sectional view of a conventional
transmission section of a drilling motor.
[0012] FIG. 2 shows a cross-sectional view of an adjustable housing
assembly of a transmission section according to embodiments
disclosed herein.
[0013] FIG. 3 shows a cross-sectional view of a transmission
section of a drilling motor according to embodiments disclosed
herein.
DETAILED DESCRIPTION
[0014] In one aspect, embodiments disclosed herein relate to a
transmission section for drilling motors used in the oil and gas
industry for drilling boreholes, particularly in applications
requiring the transfer of large torque across the transmission
section. Embodiments of the present disclosure also relate to a
transmission section of a drilling motor having a housing assembly,
such as an adjustable housing assembly, having a bore formed
therethrough that is eccentric from a center of the housing
assembly, rather than being a concentric bore formed through the
housing assembly. Illustrations of each of these embodiments are
shown.
[0015] As power sections are evolving to be stronger, the
transmission shafts that transfer torque to the driveshaft are
being subjected to significantly greater torques. The additional
force or torque requires that the transmission shaft be designed
with a larger shaft diameter than it was previously. This larger
diameter forces the bore formed through the bent housing assembly
to be larger as well. This larger bore formed through the housing
assembly drastically decreases the strength of the housing
assembly, as the outer diameter of the housing assembly must remain
constant in order to fit within a specifically-sized borehole.
[0016] Certain terms are used throughout the following description
and claims refer to particular features or components. As those
having ordinary skill in the art will appreciate, different persons
may refer to the same feature or component by different names This
document does not intend to distinguish between components or
features that differ in name but not function. The figures are not
necessarily to scale. Certain features and components herein may be
shown exaggerated in scale or in somewhat schematic form and some
details of conventional elements may not be shown in interest of
clarity and conciseness.
[0017] In the following discussion and in the claims, the terms
"including" and "comprising" are used in an open-ended fashion, and
thus should be interpreted to mean "including, but not limited to .
. . " Further, the terms "axial" and "axially" generally mean along
or substantially parallel to a central or longitudinal axis, while
the terms "radial" and "radially" generally mean perpendicular to a
central, longitudinal axis.
[0018] According to one or more embodiments, a drilling motor
assembly may include a power section configured to generate torque,
a transmission section coupled to the power section, and a bearing
section coupled to the transmission section, the bearing section
configured to couple to a drill bit. In one or more embodiments,
the power section may include a rotor that is configured to
generate torque. In one or more embodiments, the transmission
section may include a housing assembly having a bore formed
therethrough, the housing assembly having a central axis defined
therethrough and the bore having a central axis defined
therethrough, in which the central axis of the bore is radially
offset from the central axis of the housing assembly. In one or
more embodiments, the bore formed through the housing assembly may
be an eccentric bore that is formed eccentric to a center of the
housing assembly, e.g., eccentric to an outer diameter or outer
circumference of the housing assembly. For example, in one or more
embodiments, the bore formed through the housing assembly may be an
eccentric bore that is formed through the housing assembly, in
which the central axis of the bore is radially offset from the
central axis of the housing assembly. In other words, the bore that
is formed through the housing assembly may not be concentric with
the outer diameter of outer circumference of the housing assembly,
which may result in the housing assembly having a variable wall
thickness.
[0019] Further, according to one or more embodiments, the
transmission section may include a transmission shaft disposed
within the bore of the housing assembly. In one or more
embodiments, the radial offset between the central axis of the bore
and the central axis of the housing assembly may provide clearance
between the transmission shaft and an internal surface of the
housing assembly. In one or more embodiments, the transmission
shaft may be configured to transfer torque generated by the power
section of the drilling motor to the bearing section of the
drilling motor, which may be coupled to a drill bit.
[0020] In one or more embodiments, the radial offset between the
central axis of the bore and the central axis of the housing
assembly is up to 5 mm. However, those having ordinary skill in the
art will appreciate that in one or more embodiments, the radial
offset between the central axis of the bore and the central axis of
the housing assembly may be any amount greater than or less than 5
mm. For example, in one or more embodiments, the radial offset
between the central axis of the bore and the central axis of the
housing assembly may be 1 mm, 3 mm, 5 mm, 6 mm, 10 mm, or more.
Further, in one or more embodiments, the housing assembly may be
bent to a desired angle. Furthermore, as will be described below,
in one or more embodiments, the housing assembly may be an
adjustable housing assembly that may be bent to a desired
angle.
[0021] Further, in one or more embodiments, a cross-section of the
housing assembly may include a variable wall thickness. In other
words, as a result of the radial offset between the central axis of
the bore and the central axis of the housing assembly, in one or
more embodiments, the thickness of the wall of the housing assembly
may vary about the circumference of the housing assembly. In one or
more embodiments, the thickness of the wall of the housing assembly
may be measured by a distance between an outer diameter or radius
and an inter diameter or radius of the housing assembly.
[0022] As a result of the radial offset between the central axis of
the bore and the central axis of the housing assembly, in one or
more embodiments, a transmission shaft having a larger diameter may
be used. In one or more embodiments, the diameter of the
transmission shaft may be increased by up to 50%. However, those
having ordinary skill in the art will appreciate that the diameter
of the transmission shaft may be increased by more than 50% as a
result of a radial offset between the central axis of the bore and
the central axis of the housing assembly. In one or more
embodiments, the diameter of the transmission shaft may be
increased by 30% or more.
[0023] A larger-diameter transmission shaft may be able to
withstand a greater amount of torque generated by the power section
of the drilling motor before failure when compared to a
smaller-diameter transmission shaft of the same material. In other
words, in one or more embodiments, radial offset between the
central axis of the bore and the central axis of the housing
assembly may allow the outer diameter of the housing assembly and
the diameter of the bore formed through the housing assembly to
remain constant, while being able to accommodate for a
larger-diameter transmission shaft to be used and disposed within
the bore formed through the housing assembly and while still
maintaining sufficient clearance between the transmission shaft and
an inner surface of the housing assembly.
[0024] Thus, the radial offset between the central axis of the bore
and the central axis of the housing assembly may allow for a larger
ratio between the diameter of the transmission shaft and the outer
diameter of the housing assembly, i.e., the outer diameter of the
transmission section of the drilling motor. In one or more
embodiments, the ratio between the diameter of the transmission
shaft and the outer diameter of the housing assembly may be
1:2.313.
[0025] Further, in one or more embodiments, the radial offset
between the central axis of the bore and the central axis of the
housing assembly may allow for a larger ratio between the diameter
of the transmission shaft and the diameter of the bore formed
through the housing assembly, e.g., the diameters of each of the
first bore and the second bore. In one or more embodiments, the
ratio between the diameter of the transmission shaft and the
diameter of the bore may be 1:1.314.
[0026] Referring to FIG. 2, a cross-sectional view of a housing
assembly 200, specifically an adjustable housing assembly, of a
transmission section of a drilling motor, in accordance with
embodiments disclosed herein, is shown. As shown, the housing
assembly 200 is a multi-piece assembly and includes a first sub 201
coupled to a second sub 202. Those having ordinary skill in the art
will appreciate that more or less than two subs may be included in
the housing assembly 200. For example, in one or more embodiments,
one, two, three, four, or more subs may be included in the housing
assembly 200. In one or more embodiments, the first sub 201 may be
threadably coupled to the second sub 202. In one or more
embodiments, in which a housing assembly includes only a single
sub, the single-piece housing assembly may be used as described
above and may also be bent to a desired angle. Alternatively, in
one or more embodiments, each of the first sub 201 and the second
sub 202 may be threadably coupled to either side of an indexing
sleeve (not shown), in which either of the first sub 201 or the
second sub 202 may be rotated relative to the indexing sleeve to
create an offset angle between the first sub 201 and the second sub
202.
[0027] For example, as shown, the first sub 201 has a first central
axis 251 defined therethrough, and the second sub 202 has a second
central axis 252 defined therethrough. In one or more embodiments,
the first sub 201 may be coupled to the second sub 202 such that no
offset exists between the first sub 201 and the second sub 202. In
other words, in one or more embodiments, the first sub 201 may be
coupled to the second sub 202 such that the first central axis 251
of the first sub 201 may be collinear with the second central axis
252 of the second sub 202.
[0028] Alternatively, in one or more embodiments, the first sub 201
may be coupled to the second sub 202 such that an offset angle
.alpha. exists between the first central axis 251 of the first sub
201 and the second central axis 252 of the second sub 202. In other
words, in one or more embodiments, the housing assembly 200 may be
an adjustable housing assembly that may be bent such that the
offset angle .alpha. exists between the first central axis 251 of
the first sub 201 and the second central axis 252 of the second sub
202. In one or more embodiments, the offset angle .alpha. may be
any angle up to three degrees. However, those having ordinary skill
in the art will appreciate that the offset angle .alpha. may be any
angle greater than or less than three degrees. For example, in one
or more embodiments, the offset angle .alpha. between the first
central axis 251 of the first sub 201 and the second central axis
252 of the second sub 202 may be zero, one, two, three, four, five,
or more degrees. Further, those having ordinary skill in the art
will appreciate that the housing assembly 200 may be bent such that
the offset angle is any fraction of a degree.
[0029] Further, in one or more embodiments, the offset angle
.alpha. may be adjustable. For example, in one or more embodiments,
the offset angle .alpha. between the first central axis 251 of the
first sub 201 and the second central axis 252 of the second sub 202
may be adjusted between zero and three degrees.
[0030] For example, in one or more embodiments, the connection
between the first sub 201 and the second sub 202 may be configured
such that the offset angle .alpha. may be adjusted by rotating the
first sub 201 relative to the second sub 202, or alternatively
rotating the second sub 202 relative to the first sub 201, until a
desired offset angle .alpha. is achieved. For example, in one or
more embodiments, the connection between the first sub 201 and the
second sub 202 may include pitched threads that may allow the
offset angle .alpha. to be adjusted by rotating the first sub 201
relative to the second sub 201, or by rotating the second sub 202
relative to the first sub 201. Further, in one or more embodiments,
one of the first sub 201 or the second sub 202 may include a
tapered connecting portion, e.g., a tapered threaded pin
connection, that may allow the first sub 201 to be offset at the
angle .alpha. relative to the second sub 202. However, those having
ordinary skill in the art will appreciate that the connection
between the first sub 201 and the second sub 202 is not limited
only to a pitched threaded connection and may be any connection
means known in the art that may allow a predetermined offset angle
.alpha. to be achieved between the first central axis 251 of the
first sub 201 and the second central axis 252 of the second sub
202.
[0031] As discussed above, one or more embodiments may include the
indexing sleeve (not shown), which may be disposed between the
first sub 201 and the second sub 202, may be used to assist in
achieving a desired offset angle .alpha. between the first central
axis 251 of the first sub 201 and the second central axis 252 of
the second sub 202. For example, in one or more embodiments, the
indexing sleeve may include markings denoting fraction-of-a-degree
increments for orientation reference between zero and three
degrees. As such, in one or more embodiments, each of the first sub
201 and the second sub 202 may be threadably coupled to either side
of the indexing sleeve, which may be used to create an offset angle
.alpha. between the first central axis 251 of the first sub 201 and
the second central axis 252 of the second sub 202, and to denote
the offset angle .alpha. to a user so that a user may achieve an
exact, predetermined offset angle.
[0032] Further, in one or more embodiments, a bore may be formed
through the housing assembly 200. As shown, the housing assembly
200 includes the first sub 201 and the second sub 202. Further, as
shown, the first sub 201 has a first bore 204 formed therethrough,
and the second sub 202 has a second bore 205 formed therethrough.
As discussed above, in one or more embodiments, the housing
assembly 200 may be bent such that an offset angle .alpha. exists
between the first central axis 251 of the first sub 201 and the
second central axis 252 of the second sub 202. Alternatively, in
one or more embodiments, the housing assembly 200 may completely
straight, i.e., the offset angle .alpha. between the first central
axis 251 of the first sub 201 and the second central axis 252 of
the second sub 202 is zero, and a single bore may be foamed through
the first sub 201 and the second sub 202.
[0033] Still referring to FIG. 2, the first bore 204 has a first
central axis 261 defined therethrough, and the second bore 205 has
a second central axis 262 defined therethrough. As shown, the first
central axis 261 of the first bore 204 may be radially offset from
the first central axis 251 of the first sub 201 by a distance d.
Similarly, the second central axis 262 of the second bore 205 may
be radially offset from the second central axis 252 of the second
sub 202. As discussed above, in one or more embodiments, the radial
offset between the central axis of the bore and the central axis of
the housing assembly may be up to 5 mm. However, those having
ordinary skill in the art will appreciate that the radial offset
between the central axis of the bore and the central axis of the
housing assembly may include lower limits of 0.5 mm, 1 mm, 2 mm, 3
mm, and 4 mm and upper limits of 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm,
in which any lower limit described above can be used with any upper
limit
[0034] Similarly, the radial offset between the first central axis
261 of the first bore 204 and the first central axis 251 of the
first sub 201 may be up to 5 mm, and the radial offset between the
second central axis 262 of the second bore 205 and the second
central axis 252 of the second sub 202 may be up to 5 mm. In one or
more embodiments, the radial offset between the first central axis
261 of the first bore 204 and the first central axis 251 of the
first sub 201 may be equal to the radial offset between the second
central axis 262 of the second bore 205 and the second central axis
252 of the second sub 202, which may be the distance d.
[0035] Those having ordinary skill in the art will appreciate that
in one or more embodiments, the radial offset between the first
central axis 261 of the first bore 204 and the first central axis
251 of the first sub 201 and/or the radial offset between the
second central axis 262 of the second bore 205 and the second
central axis 252 of the second sub 202 may be any amount greater
than or less than 5 mm. For example, in one or more embodiments,
the radial offset between the first central axis 261 of the first
bore 204 and the first central axis 251 of the first sub 201 and
the radial offset between the second central axis 262 of the second
bore 205 and the second central axis 252 of the second sub 202 may
be 1 mm, 3 mm, 5 mm, 6 mm, 10 mm, or more. Alternatively, the first
central axis 261 of the first bore 204 may be collinear with the
first central axis 251 of the first sub 201, and the second central
axis 262 of the second bore 205 may be collinear with the second
central axis 252 of the second sub 202 such that the radial offset
is zero.
[0036] Referring now to FIG. 3, a cross-sectional view of a
transmission section of a drilling motor, in accordance with
embodiments disclosed herein, is shown. In one or more embodiments,
a drilling motor assembly may include a power section (not shown)
configured to generate torque, a transmission section coupled to
the power section, and a bearing section (not shown) coupled to the
transmission section, the bearing section configured to couple to a
drill bit.
[0037] As shown, the transmission section includes a housing
assembly 300. In one or more embodiments, the housing assembly 300
may be a multi-piece assembly and may include a first sub 301
coupled to a second sub 302. As discussed above, in one or more
embodiments, the housing assembly 300 may be an adjustable housing
assembly. Those having ordinary skill in the art will appreciate
that more or less than two subs may be included in the housing
assembly 300. For example, in one or more embodiments, one, two,
three, four, or more subs may be included in the housing assembly
300. In one or more embodiments, the first sub 301 may be
threadably coupled to the second sub 302. Alternatively, in one or
more embodiments, each of the first sub 301 and the second sub 302
may be threadably coupled to either side of an indexing sleeve 303,
in which the indexing sleeve 303 may be rotated to create an offset
angle between the first sub 301 and the second sub 302.
[0038] As shown, the first sub 301 has a first central axis 351
defined therethrough, and the second sub 302 has a second central
axis 352 defined therethrough. In one or more embodiments, the
first sub 301 may be coupled to the second sub 302 such that no
offset exists between the first sub 301 and the second sub 302. In
other words, in one or more embodiments, the first sub 301 may be
coupled to the second sub 302 such that the first central axis 351
of the first sub 301 may be collinear with the second central axis
352 of the second sub 302.
[0039] Alternatively, in one or more embodiments, the first sub 301
may be coupled to the second sub 302 such that an offset angle,
e.g., the offset angle .alpha. shown in FIG. 2, exists between the
first central axis 351 of the first sub 301 and the second central
axis 352 of the second sub 302. In other words, in one or more
embodiments, the adjustable housing assembly 300 may be bent such
that the offset angle exists between the first central axis 351 of
the first sub 301 and the second central axis 352 of the second sub
302. In one or more embodiments, the offset angle may be any angle
up to three degrees. However, those having ordinary skill in the
art will appreciate that the offset angle between the first central
axis 351 of the first sub 301 and the second central axis 352 of
the second sub 302 may be any angle greater than or less than three
degrees. For example, in one or more embodiments, the offset angle
between the first central axis 351 of the first sub 301 and the
second central axis 352 of the second sub 302 may be zero, one,
two, three, four, five, or more degrees. Further, those having
ordinary skill in the art will appreciate that the adjustable
housing assembly 300 may be bent such that the offset angle is any
fraction of a degree.
[0040] As discussed above, in one or more embodiments, the offset
angle may be adjustable. For example, in one or more embodiments,
the offset angle formed between the first central axis 351 of the
first sub 301 and the second central axis 352 of the second sub 302
may be adjusted between zero and three degrees.
[0041] For example, in one or more embodiments, the connection
between the first sub 301 and the second sub 302 may be configured
such that the offset angle, e.g., the offset angle .alpha. shown in
FIG. 2, may be adjusted by rotating the first sub 301 relative to
the second sub 302, or alternatively rotating the second sub 302
relative to the first sub 301, until a desired offset angle is
achieved. For example, in one or more embodiments, the connection
between the first sub 301 and the second sub 302 may include
pitched threads that may allow the offset angle to be adjusted by
rotating the first sub 301 relative to the second sub 302, or by
rotating the second sub 302 relative to the first sub 301. Further,
in one or more embodiments, one of the first sub 301 or the second
sub 302 may include a tapered connecting portion, e.g., a tapered
threaded pin connection, that may allow the first sub 301 to be
offset at an angle relative to the second sub 302. However, those
having ordinary skill in the art will appreciate that the
connection between the first sub 301 and the second sub 302 is not
limited only to a pitched threaded connection and may be any
connection means known in the art that may allow a predetermined
offset angle to be achieved between the first central axis 351 of
the first sub 301 and the second central axis 352 of the second sub
302.
[0042] As discussed above, one or more embodiments may include the
indexing sleeve 303, which may be disposed between the first sub
301 and the second sub 302, may be used to assist in achieving a
desired offset angle between the first central axis 351 of the
first sub 301 and the second central axis 352 of the second sub
302. For example, in one or more embodiments, the indexing sleeve
303 may include markings denoting fraction-of-a-degree increments
for orientation reference between zero and three degrees. As such,
in one or more embodiments, each of the first sub 301 and the
second sub 302 may be threadably coupled to either side of the
indexing sleeve 303, which may be used to create an offset angle
between the first central axis 351 of the first sub 301 and the
second central axis 352 of the second sub 302, and to denote the
offset angle to a user so that a user may achieve an exact,
predetermined offset angle.
[0043] Further, in one or more embodiments, a bore may be formed
through the adjustable housing assembly 300. As shown, the
adjustable housing assembly 300 includes the first sub 301 and the
second sub 302. Further, as shown, the first sub 301 has a first
bore 304 formed therethrough, and the second sub 302 has a second
bore 305 formed therethrough. As discussed above, in one or more
embodiments, the adjustable housing assembly 300 may be bent such
that an offset angle, e.g., the offset angle .alpha. shown in FIG.
2, exists between the first central axis 351 of the first sub 301
and the second central axis 352 of the second sub 302.
Alternatively, in one or more embodiments, the adjustable housing
assembly 300 may completely straight, i.e., the offset angle
between the first central axis 351 of the first sub 301 and the
second central axis 352 of the second sub 302 is zero, and a single
bore may be formed through the first sub 301 and the second sub
302.
[0044] As shown, the first bore 304 has a first central axis 361
defined therethrough, and the second bore 305 has a second central
axis 362 defined therethrough. As shown, the first central axis 361
of the first bore 304 may be radially offset from the first central
axis 351 of the first sub 301, e.g., by a distance d shown in FIG.
2. Similarly, the second central axis 362 of the second bore 305
may be radially offset from the second central axis 352 of the
second sub 302. As discussed above, in one or more embodiments, the
radial offset between the central axis of the bore and the central
axis of the adjustable housing assembly may be up to 5 mm.
Similarly, the radial offset between the first central axis 361 of
the first bore 304 and the first central axis 351 of the first sub
301 may be up to 5 mm, and the radial offset between the second
central axis 362 of the second bore 305 and the second central axis
352 of the second sub 302 may be up to 5 mm. In one or more
embodiments, the radial offset between the first central axis 361
of the first bore 304 and the first central axis 351 of the first
sub 301 may be equal to the radial offset between the second
central axis 362 of the second bore 305 and the second central axis
352 of the second sub 302, which may be any distance up to 5 mm, as
discussed above.
[0045] Those having ordinary skill in the art will appreciate that
in one or more embodiments, the radial offset between the central
axis of the bore and the central axis of the adjustable housing
assembly may be any amount greater than or less than 5 mm. For
example, in one or more embodiments, the radial offset between the
central axis of the bore and the central axis of the adjustable
housing assembly may be 1 mm, 3 mm, 5 mm, 6 mm, 10 mm, or more.
Alternatively, the first central axis 361 of the first bore 304 may
be collinear with the first central axis 351 of the first sub 301,
and/or the second central axis 362 of the second bore 305 may be
collinear with the second central axis 352 of the second sub 302
such that the radial offset is zero.
[0046] Still referring to FIG. 3, in one or more embodiments, the
transmission section may include a transmission shaft 310 disposed
within the bore of the adjustable housing assembly 300. As shown,
the transmission shaft 310 is disposed within each of the first
bore 304 formed through the first sub 301 and the second bore 305
formed through the second sub 302. In one or more embodiments, the
transmission shaft 310 may be configured to transfer torque
generated by the power section, e.g., a rotor shown on the left
side of FIG. 3, of the drilling motor to the bearing section of the
drilling motor shown on the right side of FIG. 3. In one or more
embodiments, a drill bit (not shown) may be coupled to the bearing
section, in which torque from the power section may be transferred
through the transmission shaft 310 to the drill bit.
[0047] In one or more embodiments, the radial offset between the
central axis of the bore and the central axis of the adjustable
housing assembly 300, e.g., the radial offset between the first
central axis 361 of the first bore 304 and the first central axis
351 of the first sub 301 as well as the radial offset between the
second central axis 362 of the second bore 305 and the second
central axis 352 of the second sub 302, may be sufficient to
provide clearance between the transmission shaft 310 and an
internal surface 306 of the adjustable housing assembly 300.
[0048] Further, in one or more embodiments, the radial offset
between the first central axis 361 of the first bore 304 and the
first central axis 351 of the first sub 301 as well as the radial
offset between the second central axis 362 of the second bore 305
and the second central axis 352 of the second sub 302 may be
sufficient to provide clearance between the transmission shaft 310
and the internal surface 306 of the adjustable housing assembly 300
when the adjustable housing assembly 300 is bent such that an
offset angle, e.g., the offset angle .alpha. shown in FIG. 2, is
formed between the first central axis 351 of the first sub 301 and
the second central axis 352 of the second sub 302.
[0049] In one or more embodiments, the clearance between the
transmission shaft 310 and the internal surface 306 of the
adjustable housing assembly 300 may be up to 5 mm. However, those
having ordinary skill in the art will appreciate that the clearance
between the transmission shaft 310 and the internal surface 306 of
the adjustable housing assembly 300 may be any distance greater
than or less than 5 mm. For example, in one or more embodiments,
the clearance between the transmission shaft 310 and the internal
surface 306 of the adjustable housing assembly 300 may be up to 1
mm, 2 mm, 3 mm, 6 mm, 10 mm, or more, or within a range of any such
values.
[0050] According to one or more embodiments, the radial offset
between the first central axis 361 of the first bore 304 and the
first central axis 351 of the first sub 301 as well as the radial
offset between the second central axis 362 of the second bore 305
and the second central axis 352 of the second sub 302 may allow a
diameter of the transmission shaft 310 to be increased. In other
words, the radial offset discussed above may allow a
larger-diameter transmission shaft 310 to be used in the
transmission section of the drilling motor.
[0051] In one or more embodiments, the diameter of the transmission
shaft 310 may be increased by up to 30%, while the outer diameter
of the adjustable housing assembly 300 and the diameter of the bore
formed through the adjustable housing assembly 300 are unchanged.
In other words, without changing the outer diameter of the
adjustable housing assembly 300 or the diameter of the bore formed
through the adjustable housing assembly 300, the radial offset
between the central axis of the bore and the central axis of the
adjustable housing assembly 300 may allow a larger-diameter
transmission shaft 310 to be used while still maintaining
sufficient clearance between the transmission shaft 310 and the
internal surface 306 of the adjustable housing assembly 300, even
when the adjustable housing assembly 300 is bent, as described
above.
[0052] Those having ordinary skill in the art will appreciate that
the diameter of the transmission shaft 310 may be increased by more
or less than 30%, while the outer diameter of the adjustable
housing assembly 300 and the diameter of the bore formed through
the adjustable housing assembly 300 are unchanged. For example, in
one or more embodiments, the diameter of the transmission shaft 310
may be increased by 10%, 20%, 40%, 50%, or more, while the outer
diameter of the adjustable housing assembly 300 and the diameter of
the bore formed through the adjustable housing assembly 300 are
unchanged.
[0053] In one or more embodiments, a larger-diameter transmission
shaft 310 may be able to withstand a greater amount of torque
generated by the power section of the drilling motor before failure
when compared to a smaller-diameter transmission shaft of the same
material. In other words, in one or more embodiments, radial offset
discussed above may allow the outer diameter of the adjustable
housing assembly 300 and the diameter of the bore formed through
the adjustable housing assembly 300 to remain constant, while being
able to accommodate for a larger-diameter transmission shaft to be
used and disposed within the bore formed through the adjustable
housing assembly and while still maintaining sufficient clearance
between the transmission shaft 310 and an inner surface 306 of the
adjustable housing assembly 300.
[0054] Thus, the radial offset between the central axis of the bore
and the central axis of the adjustable housing assembly 300 may
allow for a larger ratio between the diameter of the transmission
shaft 310 and the outer diameter of the adjustable housing assembly
300, i.e., the outer diameter of the transmission section of the
drilling motor. In one or more embodiments, the ratio between the
diameter of the transmission shaft 310 and the outer diameter of
the housing assembly 300 may be 1:2.313. However, one or more
embodiments may include other ratios between the diameter of the
transmission shaft 310 and the outer diameter of the housing
assembly 300.
[0055] Further, in one or more embodiments, the radial offset
between the central axis of the bore and the central axis of the
adjustable housing assembly 300 may allow for a larger ratio
between the diameter of the transmission shaft 310 and the diameter
of the bore formed through the adjustable housing assembly 300,
e.g., the diameters of each of the first bore 304 and the second
bore 305. In one or more embodiments, the ratio between the
diameter of the transmission shaft and the diameter of the bore may
be 1:1.314. However, one or more embodiments may include other
ratios between the diameter of the transmission shaft and the
diameter of the bore.
[0056] A larger ratio between the diameter of the transmission
shaft 310 and the outer diameter of the adjustable housing assembly
300 and/or a larger ratio between the the diameter of the
transmission shaft 310 and the diameter of the bore formed through
the adjustable housing assembly may allow an outer diameter of a
transmission section of a drilling motor to be minimized in order
to fit within predetermined, specified borehole sizes, while
increasing the torque threshold that the drilling motor is able to
withstand by increasing the diameter of the transmission shaft
310.
[0057] The radial offset between the central axis of the bore and
the central axis of the adjustable housing assembly 300 may allow
the diameter of the transmission shaft 310 to be increased without
increasing the diameter of the bore, e.g., the diameter of the
first bore 304 and the second bore 305 formed through the
adjustable housing assembly 300. Increasing the diameter of the
bore formed through the adjustable housing assembly 300 without
also increasing the outer diameter of the adjustable housing
assembly 300 may cause a wall-thickness of the adjustable housing
assembly 300 to decrease. Decreasing the wall-thickness of the
adjustable housing assembly 300 may compromise the structural
integrity of the adjustable housing assembly 300 under a load.
[0058] In one or more embodiments, the radial offset between the
central axis of the bore and the central axis of the adjustable
housing assembly 300 may be skewed toward the high side of the
bend, as the transmission shaft 310 may be skewed toward the high
side of the bend if the adjustable housing assembly 300 is bent.
For example, as shown, the second sub 302 is bent at an upward
angle relative to the first sub 301. As such, the first central
axis 361 of the first bore 304 and the second central axis 362 of
the second bore 305 are radially offset above the central axis 351
of the first sub 301 and the central axis 352 of the second sub
302, respectively, to accommodate the transmission shaft 310, which
is skewed to a high side of the adjustable housing assembly 300 as
a result of the bend.
[0059] According to another aspect, a method of manufacturing a
drilling motor assembly may include forming a bore through an
adjustable housing assembly, the adjustable housing assembly
including a first sub coupled to a second sub and a bore formed
therethrough, the first sub having a first central axis defined
therethrough and the second sub having a second central axis
defined therethrough. In one or more embodiments, the bore formed
through the adjustable housing assembly may include a first bore
and a second bore, in which the first bore is formed through the
first sub and the second bore is foamed through the second sub, the
first bore having a first central axis defined therethrough and the
second bore having a second central axis defined therethrough. In
one or more embodiments, the first central axis of the first sub
may be radially offset from the first central axis of the first
bore, and in which the second central axis of the second sub is
radially offset from the second central axis of the second
bore.
[0060] As discussed above, in one or more embodiments, the
adjustable housing assembly may have a bore formed therethrough,
and the adjustable housing assembly may have a central axis defined
therethrough and the bore may have a central axis defined
therethrough, in which the central axis of the bore is radially
offset from the central axis of the adjustable housing
assembly.
[0061] Referring back to FIG. 3, the transmission section of the
drilling motor may include the adjustable housing assembly 300, the
adjustable housing assembly 300 including the first sub 301 and the
second sub 302. In one or more embodiments, the first sub 301 may
have the first bore 304 formed therethrough, and the second sub 302
may have the second bore 305 formed therethrough. In one or more
embodiments, the first bore 304 has a first central axis 361
defined therethrough, and the second bore 305 has a second central
axis 362 defined therethrough.
[0062] As shown, the first bore 304 may be formed such that the
first central axis 361 of the first bore 304 may be radially offset
from the first central axis 351 of the first sub 301, e.g., by a
distance d shown in FIG. 2. Similarly, the second bore 305 may be
formed such that the second central axis 362 of the second bore 305
may be radially offset from the second central axis 352 of the
second sub 302. As discussed above, in one or more embodiments, the
radial offset between the central axis of the bore and the central
axis of the adjustable housing assembly may be up to 5 mm.
Similarly, the radial offset between the first central axis 361 of
the first bore 304 and the first central axis 351 of the first sub
301 may be up to 5 mm, and the radial offset between the second
central axis 362 of the second bore 305 and the second central axis
352 of the second sub 302 may be up to 5 mm. In one or more
embodiments, each of the first bore 304 and the second bore 305 may
be formed such that the radial offset between the first central
axis 361 of the first bore 304 and the first central axis 351 of
the first sub 301 may be equal to the radial offset between the
second central axis 362 of the second bore 305 and the second
central axis 352 of the second sub 302, which may be any distance
up to 5 mm.
[0063] The method may also include coupling a power section
configured to generate torque to a transmission section having the
adjustable housing assembly. Further, the method may include
coupling a bearing section configured to couple with a drill bit to
the transmission section having the adjustable housing assembly. As
discussed above, in one or more embodiments, a cross-section of the
adjustable housing assembly may include a variable wall
thickness.
[0064] Further, as discussed above, the transmission section may
include a transmission shaft, e.g., the transmission shaft 310,
disposed within the bore of the adjustable housing assembly. As
discussed above, the bore of the adjustable housing assembly may
include a first bore and a second bore formed through the
adjustable housing assembly, e.g., the first bore 304 formed
through the first sub 301 and the second bore 305 formed through
the second sub 302.
[0065] Furthermore, as discussed above, the radial offset between
the central axis of the bore and the central axis of the adjustable
housing assembly 300, e.g., the radial offset between the first
central axis 361 of the first bore 304 and the first central axis
351 of the first sub 301 as well as the radial offset between the
second central axis 362 of the second bore 305 and the second
central axis 352 of the second sub 302, may be sufficient to
provide clearance between the transmission shaft 310 and an
internal surface 306 of the adjustable housing assembly 300 while
also allowing a larger ratio to exist between the diameter of the
transmission shaft 310 and the outer diameter of the adjustable
housing assembly 300 and/or a larger ratio to exist between the
diameter of the transmission shaft 310 and the diameter of the bore
formed through the adjustable housing assembly.
[0066] A larger ratio between the diameter of the transmission
shaft 310 and the outer diameter of the adjustable housing assembly
300 and/or a larger ratio between the diameter of the transmission
shaft 310 and the diameter of the bore formed through the
adjustable housing assembly may allow an outer diameter of a
transmission section of a drilling motor to be minimized in order
to fit within predetermined, specified borehole sizes, while
increasing the torque threshold that the drilling motor is able to
withstand by increasing the diameter of the transmission shaft
310.
[0067] According to another aspect, a method of using a drilling
motor assembly may include disposing the drilling motor assembly
having a power section, a transmission section, and a bearing
section downhole, transmitting torque from the power section to the
bearing section through the transmission section. In one or more
embodiments, the transmission section may include an adjustable
housing assembly having a central axis defined therethrough and a
bore formed therethrough, the bore having a central axis defined
therethrough. In one or more embodiments, the central axis of the
bore is radially offset from the central axis of the adjustable
housing assembly.
[0068] As discussed above, in one or more embodiments, the
adjustable housing assembly may include a first sub and a second
sub, e.g., the first sub 301 and the second sub 302. Further, as
discussed above, the bore foamed through the adjustable housing
assembly may include a first bore and a second bore formed through
the adjustable housing assembly, e.g., the first bore 304 formed
through the first sub 301 and the second bore 305 formed through
the second sub 302.
[0069] Further, as discussed above, the radial offset between the
central axis of the bore and the central axis of the adjustable
housing assembly 300, e.g., the radial offset between the first
central axis 361 of the first bore 304 and the first central axis
351 of the first sub 301 as well as the radial offset between the
second central axis 362 of the second bore 305 and the second
central axis 352 of the second sub 302, may be sufficient to
provide clearance between the transmission shaft 310 and an
internal surface 306 of the adjustable housing assembly 300.
[0070] In one or more embodiments, having the radial offset between
the central axis of the bore and the central axis of the adjustable
housing assembly may allow a larger-diameter transmissions shaft to
be used. As discussed above, in one or more embodiments, the
diameter of the transmission shaft may be increased by up to 30%,
while the outer diameter of the adjustable housing assembly and the
diameter of the bore formed through the adjustable housing assembly
are unchanged. This larger-diameter transmission shaft may be used
while still maintaining sufficient clearance between the
transmission shaft and an internal surface of the adjustable
housing assembly, even when the adjustable housing assembly is
bent, as described above.
[0071] Although only a few example embodiments have been described
in detail above, those skilled in the art will readily appreciate
that many modifications are possible in the example embodiments
without materially departing from this invention. Accordingly, all
such modifications are intended to be included within the scope of
this disclosure as defined in the following claims. In the claims,
means-plus-function clauses are intended to cover the structures
described herein as performing the recited function and not only
structural equivalents, but also equivalent structures. Thus,
although a nail and a screw may not be structural equivalents in
that a nail employs a cylindrical surface to secure wooden parts
together, whereas a screw employs a helical surface, in the
environment of fastening wooden parts, a nail and a screw may be
equivalent structures. It is the express intention of the applicant
not to invoke 35 U.S.C. .sctn.112, paragraph 6 for any limitations
of any of the claims herein, except for those in which the claim
expressly uses the words `means for` together with an associated
function.
* * * * *