U.S. patent application number 14/479366 was filed with the patent office on 2016-03-10 for rotary steering with multiple contact points.
The applicant listed for this patent is Schlumberger Technology Corporation. Invention is credited to Guy James Rushton, Junichi Sugiura.
Application Number | 20160069139 14/479366 |
Document ID | / |
Family ID | 55437063 |
Filed Date | 2016-03-10 |
United States Patent
Application |
20160069139 |
Kind Code |
A1 |
Sugiura; Junichi ; et
al. |
March 10, 2016 |
Rotary Steering with Multiple Contact Points
Abstract
A system in which a drill string is disposed within a wellbore
that extends from a wellsite surface to a subterranean formation.
At least three rotary steerable system (RSS) modules are
collectively coupled in series between the drill string and a drill
bit. Each RSS module includes at least three steering pads spaced
circumferentially apart around a perimeter of the RSS module, and a
valve operable to sequentially actuate the steering pads. The
system also includes a controller operable to independently actuate
the valve of each RSS module simultaneously.
Inventors: |
Sugiura; Junichi; (Bristol,
GB) ; Rushton; Guy James; (Frocester, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schlumberger Technology Corporation |
Sugar Land |
TX |
US |
|
|
Family ID: |
55437063 |
Appl. No.: |
14/479366 |
Filed: |
September 7, 2014 |
Current U.S.
Class: |
175/61 ;
175/73 |
Current CPC
Class: |
E21B 17/1014 20130101;
E21B 7/06 20130101 |
International
Class: |
E21B 7/06 20060101
E21B007/06; E21B 4/02 20060101 E21B004/02 |
Claims
1. A system for drilling a wellbore, comprising: a rotary steerable
system (RSS) at least indirectly coupled between a drill string
collar and a drill bit, wherein the RSS comprises: a first section
comprising at least three first steering members and a first valve
operable to sequentially actuate the first steering members; a
second section comprising at least three second steering members
and a second valve operable to sequentially actuate the second
steering members; and a third section comprising at least three
third steering members and a third valve operable to sequentially
actuate the third steering members.
2. The system of claim 1 wherein the RSS further comprises a
controller operable to control the first, second, and third valves
to, simultaneously: sequentially actuate the first steering members
to operatively urge the first section in a first azimuthal
direction; sequentially actuate the second steering members to
operatively urge the second section in a second azimuthal direction
substantially different from the first azimuthal direction; and
sequentially actuate the third steering members to operatively urge
the third section in a third azimuthal direction substantially
different from the second azimuthal direction.
3. The system of claim 2 wherein the controller is further operable
to control the first, second, and third valves to, simultaneously:
actuate the first steering members to operatively centralize the
first section within the wellbore; actuate the second steering
members to operatively centralize the second section within the
wellbore; and sequentially actuate the third steering members to
operatively urge the third section away from a longitudinal axis of
the first and second sections.
4. The system of claim 1 wherein the RSS comprises: a first
flexible component flexibly coupling the first and second sections;
and a second flexible component flexibly coupling the second and
third sections.
5. The system of claim 1 wherein the RSS comprises: a first joint
disposed between the first and second sections; and a second joint
disposed between the second and third sections.
6. An apparatus, comprising: a drill string disposed within a
wellbore that extends from a wellsite surface to a subterranean
formation; a drill bit; at least three rotary steerable system
(RSS) modules collectively coupled in series between the drill
string and the drill bit, wherein each RSS module comprises: at
least three steering members spaced circumferentially apart around
a perimeter of the RSS module; and a valve operable to sequentially
actuate the steering pads; and a controller operable to
independently actuate the valve of each RSS module
simultaneously.
7. The apparatus of claim 6 wherein the at least three movable
steering pads of each RSS module are disposed at substantially the
same axial position.
8. The apparatus of claim 6 wherein the valve is operable to
sequentially actuate the steering pads by sequentially directing
fluid to actuators each associated with a corresponding one of the
steering pads.
9. The apparatus of claim 8 wherein the fluid directed to the
actuators is received from equipment disposed at the wellsite
surface.
10. The apparatus of claim 6 wherein the controller is operable to
actuate the valves of the RSS modules to, simultaneously:
sequentially actuate the steering pads of a first one of the RSS
modules to operatively urge the first one of the RSS modules in a
first azimuthal direction; sequentially actuate the steering pads
of a second one of the RSS modules to operatively urge the second
one of the RSS modules in a second azimuthal direction
substantially different from the first azimuthal direction; and
sequentially actuate the steering pads of a third one of the RSS
modules to operatively urge the third one of the RSS modules in a
third azimuthal direction substantially different from the second
azimuthal direction.
11. The apparatus of claim 10 wherein: the second azimuthal
direction is substantially opposite the first azimuthal direction;
and the third azimuthal direction is substantially similar to the
first azimuthal direction.
12. The apparatus of claim 11 wherein the first and third azimuthal
directions are each angularly offset from the second azimuthal
direction by an amount ranging between about 175 degrees and about
185 degrees.
13. The apparatus of claim 10 wherein the controller is further
operable to control the valves of the RSS modules to,
simultaneously: actuate the steering pads of the first one of the
RSS modules to operatively centralize the first one of the RSS
modules within the wellbore; actuate the steering pads of the
second one of the RSS modules to operatively centralize the second
one of the RSS modules within the wellbore; and sequentially
actuate the steering pads of the third one of the RSS modules to
operatively urge the third one of the RSS modules away from a
longitudinal axis of the first and second ones of the RSS
modules.
14. The apparatus of claim 6 further comprising: a first flexible
component flexibly coupling first and second ones of the RSS
modules; and a second flexible component flexibly coupling the
second one of the RSS modules and a third one of the RSS
modules.
15. The apparatus of claim 6 further comprising: a first joint
disposed between first and second ones of the RSS modules; and a
second joint disposed between the second one of the RSS modules and
a third one of the RSS modules.
16. The apparatus of claim 6 wherein the drill bit, the at least
three RSS modules, and the controller are collectively operable to
extend the wellbore with a dogleg of up to twenty degrees per 100
feet (30.5 meters).
17. A method, comprising: conveying apparatus within a wellbore
that extends from a wellsite surface to a subterranean formation,
wherein the apparatus comprises a drill string, a drill bit, and at
least three rotary steerable system (RSS) modules collectively
coupled in series between the drill string and the drill bit, and
wherein each RSS module comprises: at least three steering pads
spaced circumferentially apart around a perimeter of the RSS
module; and a valve operable to sequentially actuate the steering
pads; and operating a controller to independently actuate the valve
of each RSS module to, simultaneously: sequentially actuate the
steering pads of a first one of the RSS modules to operatively urge
the first one of the RSS modules in a first azimuthal direction;
sequentially actuate the steering pads of a second one of the RSS
modules to operatively urge the second one of the RSS modules in a
second azimuthal direction substantially different from the first
azimuthal direction; and sequentially actuate the steering pads of
a third one of the RSS modules to operatively urge the third one of
the RSS modules in a third azimuthal direction substantially
different from the second azimuthal direction.
18. The method of claim 17 further comprising operating the
controller to control the valves of the RSS modules to,
simultaneously: actuate the steering pads of the first one of the
RSS modules to operatively centralize the first one of the RSS
modules within the wellbore; actuate the steering pads of the
second one of the RSS modules to operatively centralize the second
one of the RSS modules within the wellbore; and sequentially
actuate the steering pads of the third one of the RSS modules to
operatively urge the third one of the RSS modules in an azimuthal
direction away from a longitudinal axis of the first and second
ones of the RSS modules.
19. The method of claim 17 further comprising, prior to conveying
at least a portion of the apparatus within the wellbore, coupling
the RSS modules in series between the drill string and the drill
bit.
20. The method of claim 17 further comprising, prior to conveying
at least a portion of the apparatus within the wellbore: coupling a
first flexible component between first and second ones of the RSS
modules; and coupling a second flexible component between the
second one of the RSS modules and a third one of the RSS modules.
Description
BACKGROUND OF THE DISCLOSURE
[0001] Oil and gas wellbore drilling applications may utilize a
rotary steerable system to control the direction of drilling during
formation of the wellbore. A rotary steerable system may utilize a
drill bit that is coupled with a drill collar and rotated to drill
through the subterranean formation. One or more valves and control
systems may control steering pads selectively actuated for radial
deflection to control the direction of drilling. Such valves may be
held at angular orientations with respect to the rotating drill
collar to control the flow of fluid to the steering pads. However,
such systems may not accurately control the direction of drilling,
and may be limited with regard to a maximum rate of changing of the
drilling direction.
SUMMARY OF THE DISCLOSURE
[0002] The present disclosure introduces a system for drilling a
wellbore. The system includes a rotary steerable system (RSS)
coupled between a drill string collar and a drill bit. The RSS
includes first, second, and third sections. The first section
includes three first steering pads and a first valve operable to
sequentially actuate the first steering pads. The second section
includes three second steering pads and a second valve operable to
sequentially actuate the second steering pads. The third section
includes three third steering pads and a third valve operable to
sequentially actuate the third steering pads.
[0003] The present disclosure also introduces an apparatus that
includes a drill string disposed within a wellbore that extends
from a wellsite surface to a subterranean formation. The apparatus
also includes a drill bit and three rotary steerable system (RSS)
modules collectively coupled in series between the drill string and
the drill bit. Each RSS module includes three steering pads spaced
circumferentially apart around a perimeter of the RSS module, a
valve operable to sequentially actuate the steering pads, and a
controller operable to independently actuate the valve of each RSS
module simultaneously.
[0004] The present disclosure also introduces a method comprising
conveying apparatus within a wellbore that extends from a wellsite
surface to a subterranean formation, wherein the apparatus includes
a drill string, a drill bit, and at least three rotary steerable
system (RSS) modules collectively coupled in series between the
drill string and the drill bit. Each RSS module includes: three
steering pads spaced circumferentially apart around a perimeter of
the RSS module; and a valve operable to sequentially actuate the
steering pads. The controller is operated to independently actuate
the valve of each RSS module to, simultaneously: sequentially
actuate the steering pads of a first one of the RSS modules to
operatively urge the first one of the RSS modules in a first
azimuthal direction; sequentially actuate the steering pads of a
second one of the RSS modules to operatively urge the second one of
the RSS modules in a second azimuthal direction substantially
different from the first azimuthal direction; and sequentially
actuate the steering pads of a third one of the RSS modules to
operatively urge the third one of the RSS modules in a third
azimuthal direction substantially different from the second
azimuthal direction.
[0005] These and additional aspects of the present disclosure are
set forth in the description that follows, and/or may be learned by
a person having ordinary skill in the art by reading the materials
herein and/or practicing the principles described herein. At least
some aspects of the present disclosure may be achieved via means
recited in the attached claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present disclosure is understood from the following
detailed description when read with the accompanying figures. It is
emphasized that, in accordance with the standard practice in the
industry, various features are not drawn to scale. In fact, the
dimensions of the various features may be arbitrarily increased or
reduced for clarity of discussion.
[0007] FIG. 1 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0008] FIG. 2 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0009] FIG. 3 is a perspective view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0010] FIG. 4 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0011] FIG. 5 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0012] FIG. 6 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0013] FIG. 7 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0014] FIG. 8 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
[0015] FIG. 9 is a flow-chart diagram of at least a portion of a
method according to one or more aspects of the present
disclosure.
[0016] FIG. 10 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure.
DETAILED DESCRIPTION
[0017] It is to be understood that the following disclosure
provides many different embodiments, or examples, for implementing
different features of various embodiments. Specific examples of
components and arrangements are described below to simplify the
present disclosure. These are, of course, merely examples and are
not intended to be limiting. In addition, the present disclosure
may repeat reference numerals and/or letters in the various
examples. This repetition is for simplicity and clarity, and does
not in itself dictate a relationship between the various
embodiments and/or configurations discussed. Moreover, the
formation of a first feature over or on a second feature in the
description that follows may include embodiments in which the first
and second features are formed in direct contact, and may also
include embodiments in which additional features may be formed
interposing the first and second features, such that the first and
second features may not be in direct contact.
[0018] FIG. 1 is a schematic view of at least a portion of a
drilling system 20 according to one or more aspects of the present
disclosure. The drilling system 20 may comprise a bottom hole
assembly (BHA) 22, which may be part of or coupled to a drill
string 24 utilized to form a wellbore 26 via direction drilling.
The drilling system 20 comprises a rotary steerable system (RSS) 28
comprising at least three sets of laterally movable steering pads
30. Each steering pad 30 of a set may be at substantially the same
axial position within the RSS 28. Each set of steering pads 30 is
axially offset along a longitudinal axis of the RSS 28, and may be
controlled by and/or in conjunction with a corresponding valve
system 32. Each steering pad 30 may be designed to act against a
corresponding, perhaps pivotable component of the RSS 28, and/or
against the surrounding wall of the wellbore 26, thereby providing
directional control. The valve systems 32 may each be positioned
with the corresponding set of steering pads 30 within a drill
collar of the RSS 28. The drill collar and/or other housing 35 of
the lowermost (in a downhole direction) set of steering pads 30 is
directly or indirectly coupled with a drill bit 36, which is
rotated to cut through a surrounding rock formation 38 that may be
in a hydrocarbon bearing reservoir 40.
[0019] Depending on the environment and the operational parameters
of the drilling operation, the drilling system 20 may comprise a
variety of other features. For example, the drill string 24 may
comprise additional drill collars 42 incorporating various drilling
modules, such as logging-while-drilling (LWD) and/or
measurement-while-drilling (MWD) modules 44, among others.
[0020] Various surface systems also may form a part of or otherwise
be utilized in conjunction with the drilling system 20. For
example, a drilling rig 46 positioned above the wellbore 26 may be
utilized in conjunction with a drilling fluid system 48 also
positioned at the wellsite. The drilling fluid system 48 is
operable to deliver drilling fluid (e.g., "mud") 50 from a drilling
fluid tank 52, through tubing 54, and into the drill string 24. The
drilling fluid 50 returns to the wellsite surface 10 through an
annulus 56 between the drill string 24 and the surrounding wall of
the wellbore 26. The return flow may be utilized to remove drill
cuttings resulting from operation of drill bit 36. The drilling
fluid 50 may also be utilized in conjunction with control of the
RSS 28 and the steering pads 30. That is, in addition to being
conducted by an internal passage of the drill string 24 to the
drill bit 36, the drilling fluid 50 may also be directed to or
otherwise utilized to actuate the steering pads 30. Such actuation
may be controlled by the corresponding valve systems 32, thereby
controlling the drilling direction.
[0021] The drilling system 20 may also comprise or otherwise be
utilized in conjunction with a surface control system 58. The
surface control system 58 may be utilized to control communication
with the RSS 28. For example, the surface control system 58 may
receive data from downhole sensor systems and communicates commands
to the RSS 28 to control actuation of the valve systems 32 and thus
the drilling direction. Such control electronics and/or other
control apparatus may also or instead be located downhole, perhaps
integral to the RSS 28, such as may operate in conjunction with an
orientation sensor to control the drilling direction. The downhole
control electronics may be operable to communicate with the surface
control system 58, such as to receive directional commands and/or
to relay information related to drilling and/or the formation 38 to
the surface control system 58.
[0022] The RSS 28 may be conveyed and operated within the wellbore
26 via the drill string 24, as described above. The RSS 28 may also
or instead be utilized in conjunction with a mud motor and/or
turbine, including as described below and/or otherwise within the
scope of the present disclosure. Other means of conveyance and/or
operating fluid delivery, however, may also be utilized in
implementations within the scope of the present disclosure, such as
coiled tubing, casing, and/or other tubular means.
[0023] FIG. 2 is a schematic view of at least a portion of an
example implementation of the RSS 28 according to one or more
aspects of the present disclosure. FIG. 2 more clearly depicts how
the RSS 28 may comprise a first section 12, a second section 13,
and a third section 14, coupled together in series. Each section
12-14 may be a module, sub, sub-assembly, portion, and/or other
type of section assembled into and/or otherwise partially forming
the RSS 28. Also, although not depicted in FIG. 2, flexible and/or
other intervening components may be coupled between ones of the RSS
sections 12-14.
[0024] Referring to FIGS. 1 and 2, collectively, the drill bit 36
may be mounted to the housing 35 of the lowermost (in a downhole
direction) RSS section 14. A housing 34 of the uppermost (in an
uphole direction) RSS section 12 may comprise or be coupled to an
uphole connector (not shown) of the RSS 28, such as may be operable
to couple the RSS 28 to an adjacent drill collar and/or other
component of the drill string 24. A housing 37 of the intermediate
RSS section 13 may be coupled to or otherwise between the housing
34 of the upper RSS section 12 and the housing 35 of the lower RSS
section 14. Such coupling of the upper housing 34, the intermediate
housing 37, and the lower housing 35, in series, may be via
industry-standard fittings (such as box-pin connections), threaded
engagement, and/or other means. Also, as described above, such
coupling may be in conjunction with one or more flexible
components. That is, the RSS sections 12-14 may be directly coupled
to each, or they may be indirectly coupled to each other via one or
more flexible and/or other intervening components. One or more of
the RSS sections 12-14 may also comprise one or more flexible
components, such as may provide a greater degree of bending or
rotation between neighboring ones of the RSS sections 12-14. The
RSS sections 12-14, the flexible components, and/or other
intervening components may be modular, such as may provide a degree
of interchangeability.
[0025] A variety of RSS components are carried within internal
passages 62 of the housings 34, 35, and 37, such as may be operable
for actuation of the steering pads 30 mounted to the corresponding
housings 34, 35, and 37. In the example implementation(s) described
below, each steering pad 30 may be moved radially outward from the
corresponding housing 34, 35, or 37 by a corresponding piston 64,
which may be hydraulically actuated via drilling fluid 50 metered
by the corresponding valve system 32. However, each piston 64 may
extend a sufficient distance from the corresponding housing 34, 35,
or 37 so as to contact the sidewall of the wellbore, instead of
urging the steering pad 30 into contact with the sidewall of the
wellbore. Accordingly, reference herein to the steering pads 30
being actuated for intermittent contact with the sidewall of the
wellbore is deemed to include implementations lacking actual
steering pads and instead comprising an actuator and/or other
device (e.g., the piston 64) operable to intermittently contact the
sidewall of the wellbore, and which may hereafter be referred to
herein as steering members. Moreover, hydraulic oil and/or other
fluids carried internally with the RSS 28 and/or another component
of the BHA or drill string may also or instead be utilized to
activate the steering pads 30, pistons 64, and/or similarly
functioning apparatus.
[0026] Each valve system 32 may comprise a rotational, spider,
barrel, digital, and/or other type of valve 66. Each valve 66 may
be selectively rotated, digitally actuated, and/or otherwise
actuated to direct a portion of the drilling fluid 50 from the
corresponding internal passage 62 to selected ones of the steering
pads 30. For example, one or more hydraulic lines 68 may
communicate drilling fluid 50 from the corresponding valve 66 to
act against the pistons 64 corresponding to the steering pads 30.
The housings 34, 35, and 37 and the drill bit 36 rotate during
drilling of the wellbore 26, during which time each valve 66 may
undergo a controlled, relative rotation to selectively deliver the
drilling fluid 50 through the corresponding hydraulic line(s) 68 to
the corresponding steering pads 30.
[0027] With each valve system 32, the valve 66 may be coupled to or
otherwise driven by a shaft 70, which may be rotated by a
corresponding electric and/or other type of motor 72. One or more
encoders and/or other sensors 74 may be operatively engaged with
the shaft 70 to monitor the angular orientation of each valve 66
relative to the corresponding housing 34, 35, or 37. Each valve
system 32, or other component of the RSS 28, may also comprise one
or more control devices 75, such as may comprise and/or operate in
conjunction with a microprocessor and/or other controller 76. The
control devices 75 and/or controllers 76 may each receive data from
the corresponding sensors 74 and utilize such data and/or other
data to control the corresponding motor 72. Each motor 72 may thus
be operable in controlling the angular positioning of the
corresponding valve 66. One or more of the control devices 75
and/or controllers 76 may also communicate with the surface control
system 58, such as to receive commands and/or relay data. One or
more of the control devices 75 and/or controllers 76 may also
comprise and/or operate in conjunction with one or more additional
components, such as a direction and inclination package containing
magnetometers and accelerometers (not shown).
[0028] Operational power may be provided to each control device 75,
controller 76, motor 72, and/or other components of the RSS 28 via
one or more power sources, such as may be or comprise batteries
and/or a turbine 80. Each turbine 80 may comprise and/or operate in
conjunction with an alternator 82 driven by rotation of the turbine
80, such rotation being in response to the pressurized flow of the
drilling fluid 50 through the internal passages 62.
[0029] One or more components of each valve system 32 and/or other
component of the RSS 28 may be mounted within a pressure housing
86, such as may provide a level of protection against the
relatively high pressure of the drilling fluid 50 and/or the rigors
of the downhole environment. For example, the motors 72, encoders
74, control devices 75, controllers 76, and alternators 82 may be
disposed within corresponding pressure housings 86 associated with
each RSS section 12-14. Each pressure housing 86 may be rigidly
attached to the corresponding housing 34, 35, and 37 via one or
more centralizers and/or other members 88 disposed within the
corresponding housing 34, 35, or 37. Thus, each pressure housing 86
may rotate with the corresponding housing 34, 35, or 37.
[0030] Each valve system 32 may comprise a valve 66, one or more
hydraulic lines 68, a shaft 70, a motor 72, one or more sensors 74,
a control device 75, a controller 76, a turbine 80 and/or other
power source, an alternator 82, a pressure housing 86, combinations
thereof, and/or other components. Two or more of the RSS sections
12-14, however, may share one or more components of the valves
systems 32. For example, a single control device 75 and/or
controller 76 may be operable to control the valves 66 of two or
more of the RSS sections 12-14.
[0031] Each RSS section 12-14 comprises at least three steering
pads 30. Each steering pad 30 of a set may be at substantially the
same axial position relative to the corresponding RSS section
12-14. Thus, the steering pads 30 of the upper RSS section 12 may
each be positioned at a first axial position relative to the RSS
28, the steering pads 30 of the intermediate RSS section 13 may
each be positioned at a second axial position relative to the RSS
28, and the steering pads 30 of the lower RSS section 14 may each
be positioned at a third axial position relative to the RSS 28,
wherein the first, second, and third axial positions are axially
offset from one another along the length of the RSS 28.
[0032] Each steering pad 30 may be activated by differential
pressure, such as between the inside and outside of the
corresponding housing 34, 35, or 37. When a steering pad 30 is
activated, it pivots away from the RSS 28, ultimately pushing
against the sidewall of the wellbore 26, thus deflecting the
corresponding RSS section 12-14 in the opposite direction, thereby
providing the RSS 28 with steering capability. As the housings 34,
35, and 37 rotate (substantially simultaneously), each valve 66
selectively operates to cause the extension and retraction of the
corresponding steering pads 30 by alternatingly permitting and
restricting the flow of drilling fluid 50 through the corresponding
hydraulic line 68 to the corresponding piston 64 behind the
steering pad 30. The steering pads 30 may thus rotate substantially
simultaneously with the bit rotation speed. However, in other
implementations within the scope of the present disclosure,
substantially non-rotating pads may be utilized.
[0033] FIG. 3 is an exploded view of an example implementation of
at least a portion of one of the valves 66. The valve 66 comprises
a valve opening 90 that is rotated via operation of the motor 72.
The valve opening 90 may be selectively aligned with selected ports
92 that are part of and/or rotate with the corresponding housing
34, 35, or 37. The ports 92 deliver drilling fluid 50 into
hydraulic lines 68 for subsequent communication to the
corresponding steering pads 30. In the example implementation
depicted in FIGS. 1-3, each housing 34, 35, and 37 comprises three
ports 92 connected to three steering pads 30 via hydraulic lines
68, although other implementations within the scope of the present
disclosure may include ports 92 and/or steering pads 30 in other
numbers.
[0034] The valve opening 90 may be selectively aligned with
individual ports 92 or combinations of adjacent ports 92. Each
valve 66 is selectively rotated via the shaft 70 and the motor 72
to bring the valve opening 90 into alignment or out of alignment
with a selected one or two ports 92.
[0035] FIG. 4 is a sectional view of the steering pads 30 carried
by the upper housing 34, the valve 66, and the related components.
To facilitate an understanding of the angular relationship of the
valve opening 90 with respect to the ports 92, the ports 92 have
been labeled as first (1), second (2), and third (3) ports 92,
corresponding with first (1), second (2), and third (3) steering
pads 30. The first (1), second (2), and third (3) ports 92 and
steering pads 30 are illustrated as positioned substantially at
0.degree., 120.degree., and 240.degree., respectively, around the
housing 34. If the valve 66 and the housing 34 are both positioned
at 0.degree., then the first (1) port 92 is activated by the
pressure of drilling fluid 50, but the second and third ports are
not activated. If the angle of the housing 34 is substantially
0.degree. while the angle of the valve 66 is substantially
60.degree., then the first (1) and second (2) ports 92 are both
activated.
[0036] The size of the valve opening 90 and each of the ports 92
may vary according to a variety of design parameters. For example,
the valve opening 90 may have an angular width of about 90.degree.
and each of the ports 92 may have an angular width of about
80.degree.. However, the angular widths and/or other dimensions of
the valve opening 90 and the ports 92 may vary within the scope of
the present disclosure. The number of openings 90, ports 92, and
hydraulic lines 68 may also vary within the scope of the present
disclosure, such as in accord with the number of steering pads 30
of a corresponding RSS section 12-14 (which may also vary within
the scope of the present disclosure).
[0037] FIG. 5 is a simplified sectional view of the RSS 28 shown in
FIGS. 1-4, in which the valve systems 32 and hydraulic lines 68 are
simplified for clarity of the following description. The RSS 28 is
at least indirectly coupled between a collar 110 of the drill
string 24 and the drill bit 36. As described above, the RSS 28
comprises a first section 12, a second section 13, and a third
section 14, where each RSS section 12-14 comprises at least three
steering pads 30 and a valve system 32 operable to sequentially
actuate the steering pads 30. In the example implementation
depicted in FIG. 5, each RSS section 12-14 comprise two
diametrically opposed steering pads 30. However, other
implementations within the scope of the present disclosure may not
comprise diametrically opposed steering pads 30.
[0038] The example RSS 28 depicted in FIG. 5 also comprises a
controller 130 operable to control each of the valve systems 32.
The controller 130 may comprise one or more instances of the
control devices 75 and/or controllers 76 shown in FIG. 2. The
controller 130 may be a single, discrete controller operable to
control each of the valve systems 32, such that control/data lines
132 may extend between the controller 130 and the valves 66. Other
implementations within the scope of the present disclosure,
however, may utilize multiple controllers 130 each operable to
control a corresponding one of the valve systems 32. Where multiple
controllers are utilized, two or more (or each) of the controllers
may be operably connected to a common communication bus, such that
steering pad 30 activations may occur synchronously. The common or
"main" controller may be located somewhere else in the BHA, such as
in an MWD tool. One or more of the controllers may also be operable
to communicate with other tools of the BHA, such as formation
testing tools of MWD and/or LWD modules, via a common communication
bus. For example, for closed-loop geosteering, the steering pad
controllers may operable in conjunction with formation data
obtained by an LWD of the BHA, such as to reference a formation
feature that may utilized to guide steering. Thus, among other
possible implementations, the LWD module may be utilized to obtain
formation image data that may then be utilized with the steering
pad controllers to maintain the drilling path within a pay-zone of
the formation while elongating the wellbore.
[0039] The steering pad and/or other downhole controllers of the
RSS 28 and/or other portions of the BHA may communicate with
surface equipment (e.g., the surface control system 58 in FIG. 1)
in substantially real-time manner. For example, such communication
may be via wired drill pipe, electromagnetic (EM) telemetry, and/or
others. However, mud pulse telemetry is also contemplated.
[0040] FIG. 6 is a schematic exterior view of the RSS 28 shown in
FIG. 5 after the controller 130 has operably controlled the valve
systems 32 to, simultaneously: sequentially actuate the steering
pads 30 of the upper RSS section 12 to urge the upper RSS section
12 in a first azimuthal direction 140 relative to a longitudinal
axis 160 of the wellbore 26; sequentially actuate the steering pads
30 of the middle RSS section 13 to urge the middle RSS section 13
in a second azimuthal direction 150 relative to the longitudinal
axis 160 of the wellbore 26; and sequentially actuate the steering
pads 30 the lower RSS section 14 to operatively urge the lower RSS
section 14 in the first azimuthal direction 140 relative to a
longitudinal axis 160 of the wellbore 26. That is, a first steering
pad of the upper RSS section 12, indicated in FIG. 6 as steering
pad 170, has been actuated and is thus pushing against the sidewall
of the wellbore 26, thereby urging the upper RSS section 12 in the
first azimuthal direction 140. However, a second steering pad of
the upper RSS section 12, indicated in FIG. 6 as steering pad 180,
has not been actuated and thus remains substantially retracted
against the housing 34 of the upper RSS section 12, thereby
permitting the upper RSS section 12 to travel in the first
azimuthal direction 140. Simultaneously, a first steering pad of
the intermediate RSS section 13, indicated in FIG. 6 as steering
pad 171, has been actuated and is thus pushing against the sidewall
of the wellbore 26, thereby urging the intermediate RSS section 13
in the second azimuthal direction 150. However, a second steering
pad of the intermediate RSS section 13, indicated in FIG. 6 as
steering pad 181, has not been actuated and thus remains
substantially retracted against the housing 37 of the intermediate
RSS section 13, thereby permitting the intermediate RSS section 13
to travel in the second azimuthal direction 150. Also
simultaneously, a first steering pad of the lower RSS section 14,
indicated in FIG. 6 as steering pad 172, has been actuated and is
thus pushing against the sidewall of the wellbore 26, thereby
urging the lower RSS section 14 in the first azimuthal direction
140. However, a second steering pad of the lower RSS section 14,
indicated in FIG. 6 as steering pad 182, has not been actuated and
thus remains substantially retracted against the housing 35 of the
lower RSS section 14, thereby permitting the lower RSS section 14
to travel in the first azimuthal direction 140.
[0041] The second azimuthal direction 150 may be substantially
opposite the first azimuthal direction 140. For example, the first
and second azimuthal directions 140 and 150, respectively, may be
angularly offset by an amount ranging between about 175 degrees and
about 185 degrees. Such implementations may permit a dogleg of the
wellbore 26 to be as high as about twenty degrees per 100 feet (or
about twenty degrees per about 30.5 meters), although other values
are also within the scope of the present disclosure. For example,
referring to FIG. 1, the example wellbore 26 may change in
direction by a dogleg angle 27 ranging up to about twenty degrees
over a length 29 of the wellbore 26 that may be about 100 feet
long, as measured along the longitudinal axis 160 of the wellbore
26.
[0042] Of course, other control schemes are also within the scope
of the present disclosure. In general, the steering pads of each
RSS section 12-14 may be controlled independently of the steering
pads of each other RSS section 12-14, such that each RSS section
12-14 may be urged in a mutually different azimuthal direction.
[0043] Another example control scheme by which the steering pads of
the individual RSS sections 12-14 may be controlled by the
controller 130 is depicted in FIG. 7, in which the controller 130
has operably controlled the valve systems 32 to, simultaneously:
simultaneously actuate each of the steering pads 30 of the upper
RSS section 12 to centralize the upper RSS section 12 in the
wellbore 26; simultaneously actuate each of the steering pads 30 of
the intermediate RSS section 13 to centralize the intermediate RSS
section 13 in the wellbore 26; and sequentially actuate the
steering pads 30 the lower RSS section 14 to operatively urge the
lower RSS section 14 in a steering direction 165 relative to a
longitudinal axis 160 of the wellbore 26. That is, each steering
pad 30 of the upper RSS section 12 has been actuated and is thus
pushing against the sidewall of the wellbore 26, thereby urging the
upper RSS section 12 towards the longitudinal axis 160 of the
wellbore 26. Simultaneously, each steering pad 30 of the
intermediate RSS section 13 has been actuated and is thus pushing
against the sidewall of the wellbore 26, thereby urging the
intermediate RSS section 13 towards the longitudinal axis 160 of
the wellbore 26. Also simultaneously, a first steering pad of the
lower RSS section 14, indicated in FIG. 7 as steering pad 191, has
been actuated and is thus pushing against the sidewall of the
wellbore 26, thereby urging the lower RSS section 14 in the
steering direction 165. However, a second steering pad of the lower
RSS section 14, indicated in FIG. 7 as steering pad 192, has not
been actuated and thus remains substantially retracted against the
housing 35 of the lower RSS section 14, thereby permitting the
lower RSS section 14 to be azimuthally deflected and thereby point
in the steering direction 165.
[0044] Another example control scheme (not shown) may be utilized
to achieve a substantially neutral drilling tendency wherein each
steering pad 30 of each RSS section 12-14 is simultaneously
activated. For example, in such implementations utilizing rotary
valves, the valves may be disengaged (such as by axial motion away
from the openings leading to the steering pads 130), thus allowing
drilling or other working fluid to simultaneously actuate each
steering pad 30 associated with that valve. Similarly, in
implementations utilizing digital valves, they may be digitally
operated to simultaneously actuate each steering pad 30.
[0045] FIG. 8 is a side view of the RSS 28 shown in FIGS. 5-7 and
demonstrating that one or more flexible components may be formed
with or otherwise coupled between the RSS sections 12-14. For
example, a flexible component 210 may be coupled between the upper
RSS section 12 and the adjacent component 110 of the drill string
24 (see FIG. 1). Another flexible component 211 may be coupled
between the upper RSS section 12 and the intermediate RSS section
13. Another flexible component 212 may be coupled between the
intermediate RSS section 13 and the lower RSS section 14. One or
more of the flexible components 210-212 may be or comprise a
universal joint and/or other joint permitting relative bending
between neighboring RSS sections 12-14 and the drill string
component 110 while transferring rotary motion across the joint.
One or more of the flexible components 210-212 may also or instead
be or comprise a flex-sub, bent-sub, and/or other components
operable to permit relative bending of RSS sections 12-14 during
rotation.
[0046] The steerable system shown in FIGS. 1-8, described above,
and/or otherwise within the scope of the present disclosure may be
operable to counter the tendency of previous steering systems to
buckle in response to excessive weight-on-bit. A steerable system
according to one or more aspects of the present disclosure may also
aid in ensuring that the steering pads furthest from the drill bit
(i.e., in an uphole direction) contact the sidewalls of the
wellbore, and as such may be utilized instead of or in addition to
the upper stabilizer of a conventional RSS BHA. A steerable system
according to one or more aspects of the present disclosure may also
aid in dampening vibrations caused by drilling operations, such as
by utilizing the upper and/or intermediary (relative to the drill
bit, in an uphole direction) set of steering pads to press against
the sidewalls of the wellbore, while maintaining an intended
drilling direction.
[0047] FIG. 9 is a flow-chart diagram of at least a portion of a
method (900) according to one or more aspects of the present
disclosure. The method (900) may be executed utilizing at least a
portion of the apparatus shown in one or more of FIGS. 1-8, among
other apparatus within the scope of the present disclosure. For
example, the method (900) may comprise conveying such apparatus
within a wellbore that extends from a wellsite surface to a
subterranean formation, wherein the wellbore may be substantially
similar to the wellbore 26 shown in one or more of FIGS. 1, 6, and
7. Such apparatus may comprise or be utilized in conjunction with a
drill string, a drill bit, and at least three RSS modules and/or
other sections collectively coupled in series between the drill
string and the drill bit, such as the drill string 24, the drill
bit 36, and the RSS sections 12-14 shown in one or more of FIGS. 1,
2, and 5-8. The method (900) may comprise coupling (910) the RSS
sections between the drill string and the drill bit, which may
include coupling (915) one or more flexible components between ones
of the RSS sections. As described above, each RSS section may
comprise at least three steering pads spaced circumferentially
apart around a perimeter of the RSS section, and a rotational valve
operable to sequentially actuate the steering pads. The steering
pads 30 may be substantially similar to those shown in one or more
of FIGS. 1, 2, and 4-8, and the rotational valve may be
substantially similar to at least a portion of the valve systems 32
shown in one or more of FIGS. 1-8.
[0048] The method (900) comprises operating (920) a controller to
independently actuate the rotational valve of each RSS section. The
controller may be substantially similar to the control devices 75,
controllers 76, and/or controller 130 shown in one or more of FIGS.
2 and 5. Such operation (920) of the controller may comprise
simultaneously: actuating the steering pads of a first one of the
RSS modules sequentially to operatively urge (922) a first RSS
section in a first azimuthal direction (such as the azimuthal
direction 140 shown in FIG. 6); actuating the steering pads of a
second one of the RSS modules sequentially to operatively urge
(924) a second RSS section in a second azimuthal direction
substantially different from the first azimuthal direction (such as
the azimuthal direction 150 shown in FIG. 6); and actuating the
steering pads of a third RSS section sequentially to operatively
urge (926) a third RSS section in a third azimuthal direction
substantially different from the second azimuthal direction. The
second azimuthal direction may be substantially opposite the first
azimuthal direction, and the third azimuthal direction may be
substantially similar to the first azimuthal direction. For
example, the first and third azimuthal directions may each be
angularly offset from the second azimuthal direction by an amount
ranging between about 175 degrees and about 185 degrees.
[0049] The method (900) may further comprise operating (930) the
controller to control the rotational valves of the RSS modules to,
simultaneously: actuate the steering pads of the first RSS section
to operatively centralize (932) the first RSS section within the
wellbore; actuate the steering pads of the second RSS section to
operatively centralize (934) the second RSS section within the
wellbore; and sequentially actuate the steering pads of the third
RSS section to steer (936) the RSS with the third RSS section by
urging the third RSS section in an azimuthal direction away from a
longitudinal axis of the first and second RSS modules.
[0050] FIG. 10 is a schematic view of at least a portion of
apparatus according to one or more aspects of the present
disclosure. The apparatus is or comprises a processing system 1300
that may execute example machine-readable instructions to implement
at least a portion of one or more of the methods and/or processes
described herein, and/or to implement a portion of one or more of
the example RSS sections and/or other downhole tools described
herein. The processing system 1300 may be or comprise, for example,
one or more processors, controllers, special-purpose computing
devices, servers, personal computers, personal digital assistant
("PDA") devices, smartphones, internet appliances, and/or other
types of computing devices. Moreover, while it is possible that the
entirety of the processing system 1300 shown in FIG. 10 is
implemented within downhole apparatus, perhaps as at least a
portion of the control devices 75, controllers 76, controller 130,
other downhole apparatus shown in one or more of FIGS. 1-8, and/or
other downhole apparatus, it is also contemplated that one or more
components or functions of the processing system 1300 may be
implemented in wellsite surface equipment, perhaps including the
surface control system 58 depicted in FIG. 1 and/or other surface
equipment.
[0051] The processing system 1300 may comprise a processor 1312
such as, for example, a general-purpose programmable processor. The
processor 1312 may comprise a local memory 1314, and may execute
coded instructions 1332 present in the local memory 1314 and/or
another memory device. The processor 1312 may execute, among other
things, machine-readable instructions or programs to implement the
methods and/or processes described herein. The programs stored in
the local memory 1314 may include program instructions or computer
program code that, when executed by an associated processor, enable
surface equipment and/or downhole controller and/or control system
to perform tasks as described herein. The processor 1312 may be,
comprise, or be implemented by one or a plurality of processors of
various types suitable to the local application environment, and
may include one or more of general-purpose computers, special
purpose computers, microprocessors, digital signal processors
("DSPs"), field-programmable gate arrays ("FPGAs"),
application-specific integrated circuits ("ASICs"), and processors
based on a multi-core processor architecture, as non-limiting
examples. Of course, other processors from other families are also
appropriate.
[0052] The processor 1312 may be in communication with a main
memory, such as may include a volatile memory 1318 and a
non-volatile memory 1320, perhaps via a bus 1322 and/or other
communication means. The volatile memory 1318 may be, comprise, or
be implemented by random access memory (RAM), static random access
memory (SRAM), synchronous dynamic random access memory (SDRAM),
dynamic random access memory (DRAM), RAMBUS dynamic random access
memory (RDRAM) and/or other types of random access memory devices.
The non-volatile memory 1320 may be, comprise, or be implemented by
read-only memory, flash memory and/or other types of memory
devices. One or more memory controllers (not shown) may control
access to the volatile memory 1318 and/or the non-volatile memory
1320.
[0053] The processing system 1300 may also comprise an interface
circuit 1324. The interface circuit 1324 may be, comprise, or be
implemented by various types of standard interfaces, such as an
Ethernet interface, a universal serial bus (USB), a third
generation input/output (3GIO) interface, a wireless interface,
and/or a cellular interface, among others. The interface circuit
1324 may also comprise a graphics driver card. The interface
circuit 1324 may also comprise a communication device such as a
modem or network interface card to facilitate exchange of data with
external computing devices via a network (e.g., Ethernet
connection, digital subscriber line ("DSL"), telephone line,
coaxial cable, cellular telephone system, satellite, etc.).
[0054] One or more input devices 1326 may be connected to the
interface circuit 1324. The input device(s) 1326 may permit a user
to enter data and commands into the processor 1312. The input
device(s) 1326 may be, comprise, or be implemented by, for example,
a keyboard, a mouse, a touchscreen, a track-pad, a trackball, an
isopoint, and/or a voice recognition system, among others.
[0055] One or more output devices 1328 may also be connected to the
interface circuit 1324. The output devices 1328 may be, comprise,
or be implemented by, for example, display devices (e.g., a liquid
crystal display or cathode ray tube display (CRT), among others),
printers, and/or speakers, among others.
[0056] The processing system 1300 may also comprise one or more
mass storage devices 1330 for storing machine-readable instructions
and data. Examples of such mass storage devices 1330 include floppy
disk drives, hard drive disks, compact disk (CD) drives, and
digital versatile disk (DVD) drives, among others. The coded
instructions 1332 may be stored in the mass storage device 1330,
the volatile memory 1318, the non-volatile memory 1320, the local
memory 1314, and/or on a removable storage medium 1334, such as a
CD or DVD. Thus, the modules and/or other components of the
processing system 1300 may be implemented in accordance with
hardware (embodied in one or more chips including an integrated
circuit such as an application specific integrated circuit), or may
be implemented as software or firmware for execution by a
processor. In particular, in the case of firmware or software, the
embodiment can be provided as a computer program product including
a computer readable medium or storage structure embodying computer
program code (i.e., software or firmware) thereon for execution by
the processor.
[0057] In view of the description above, the claims below, and each
of the figures, collectively, a person having ordinary skill in the
art will readily recognize that the present disclosure introduces a
system for drilling a wellbore comprising: a rotary steerable
system (RSS) at least indirectly coupled between a drill string
collar and a drill bit, wherein the RSS comprises: a first section
comprising at least three first steering members (e.g., actuators
and/or pads) and a first valve operable to sequentially actuate the
first steering members; a second section comprising at least three
second steering members and a second valve operable to sequentially
actuate the second steering members; and a third section comprising
at least three third steering members and a third valve operable to
sequentially actuate the third steering members.
[0058] The first valve may be a first rotational valve, the second
valve may be a second rotational valve, and the third valve may be
a third rotational valve. The first valve may be a first digital
valve, the second valve may be a second digital valve, and the
third valve may be a third digital valve.
[0059] The RSS may comprise a controller operable to control the
first, second, and third valves. The controller may be operable to
control the first, second, and third valves to, simultaneously:
sequentially actuate the first steering members to operatively urge
the first section in a first azimuthal direction; sequentially
actuate the second steering members to operatively urge the second
section in a second azimuthal direction substantially different
from the first azimuthal direction; and sequentially actuate the
third steering members to operatively urge the third section in a
third azimuthal direction substantially different from the second
azimuthal direction. The second azimuthal direction may be
substantially opposite the first azimuthal direction, and the third
azimuthal direction may be substantially similar to the first
azimuthal direction. The first and third azimuthal directions may
each be angularly offset from the second azimuthal direction by an
amount ranging between about 175 degrees and about 185 degrees. The
controller may be further operable to control the first, second,
and third valves to, simultaneously: actuate the first steering
members to operatively centralize the first section within the
wellbore; actuate the second steering members to operatively
centralize the second section within the wellbore; and sequentially
actuate the third steering members to operatively urge the third
section away from a longitudinal axis of the first and second
sections.
[0060] The RSS may comprise: a first flexible component flexibly
coupling the first and second sections; and a second flexible
component flexibly coupling the second and third sections.
[0061] The RSS may comprise: a first joint disposed between the
first and second sections; and a second joint disposed between the
second and third sections. The first joint may be directly coupled
to at least one of the first and second sections, and the second
joint may be directly coupled to at least one of the second and
third sections.
[0062] The at least three first steering members may be spaced
circumferentially apart at a first axial position, the at least
three second steering members may be spaced circumferentially apart
at a second axial position that may be axially offset from the
first axial position, and the at least three third steering members
may be spaced circumferentially apart at a third axial position
that may be axially offset from the first and second axial
positions.
[0063] The RSS and drill bit may be operable to extend a wellbore
with a dogleg of up to twenty degrees per 100 feet (30.5
meters).
[0064] The present disclosure also introduces an apparatus
comprising: a drill string disposed within a wellbore that extends
from a wellsite surface to a subterranean formation; a drill bit;
at least three rotary steerable system (RSS) modules collectively
coupled in series between the drill string and the drill bit,
wherein each RSS module comprises: at least three steering pads
(and/or actuators and/or other steering members) spaced
circumferentially apart around a perimeter of the RSS module; and a
valve operable to sequentially actuate the steering pads; and a
controller operable to independently actuate the valve of each RSS
module simultaneously. The at least three movable steering pads of
each RSS module may be disposed at substantially the same axial
position.
[0065] The valve may be operable to sequentially actuate the
steering pads by sequentially directing fluid to actuators each
associated with a corresponding one of the steering pads. The fluid
directed to the actuators may be received from equipment disposed
at the wellsite surface. The fluid directed to the actuators may be
hydraulic oil carried in an internal chamber of the drill
string.
[0066] Each RSS module may comprise: an uphole interface; a
downhole interface; and a central portion comprising the at least
three steering pads and the valve. The uphole interface may be a
pin-end of a first box-pin coupling, and the downhole interface may
be a box-end of a second box-pin coupling. Each RSS module may
comprise a flexible portion coupled between the central portion and
one of the uphole and downhole interfaces. The flexible portion may
comprise a joint. The joint may be a universal joint. Each RSS
module may comprise a passageway fluidly connecting the uphole and
downhole interfaces.
[0067] The controller may be operable to actuate the valves of the
RSS modules to, simultaneously: sequentially actuate the steering
pads of a first one of the RSS modules to operatively urge the
first one of the RSS modules in a first azimuthal direction;
sequentially actuate the steering pads of a second one of the RSS
modules to operatively urge the second one of the RSS modules in a
second azimuthal direction substantially different from the first
azimuthal direction; and sequentially actuate the steering pads of
a third one of the RSS modules to operatively urge the third one of
the RSS modules in a third azimuthal direction substantially
different from the second azimuthal direction. The second azimuthal
direction may be substantially opposite the first azimuthal
direction, and the third azimuthal direction may be substantially
similar to the first azimuthal direction. The first and third
azimuthal directions may be each angularly offset from the second
azimuthal direction by an amount ranging between about 175 degrees
and about 185 degrees. The controller may be further operable to
control the valves of the RSS modules to, simultaneously: actuate
the steering pads of the first one of the RSS modules to
operatively centralize the first one of the RSS modules within the
wellbore; actuate the steering pads of the second one of the RSS
modules to operatively centralize the second one of the RSS modules
within the wellbore; and sequentially actuate the steering pads of
the third one of the RSS modules to operatively urge the third one
of the RSS modules away from a longitudinal axis of the first and
second ones of the RSS modules.
[0068] The apparatus may further comprise: a first flexible
component flexibly coupling first and second ones of the RSS
modules; and a second flexible component flexibly coupling the
second one of the RSS modules and a third one of the RSS modules.
The apparatus may further comprise: a first joint disposed between
first and second ones of the RSS modules; and a second joint
disposed between the second one of the RSS modules and a third one
of the RSS modules. The first joint may be directly coupled to at
least one of the first and second ones of the RSS modules, and the
second joint may be directly coupled to at least one of the second
and third ones of the RSS modules.
[0069] The drill bit, the at least three RSS modules, and the
controller may be collectively operable to extend the wellbore with
a dogleg of up to twenty degrees per 100 feet (30.5 meters).
[0070] The present disclosure also introduces a method comprising:
conveying apparatus within a wellbore that extends from a wellsite
surface to a subterranean formation, wherein the apparatus
comprises a drill string, a drill bit, and at least three rotary
steerable system (RSS) modules collectively coupled in series
between the drill string and the drill bit, and wherein each RSS
module comprises: at least three steering pads (and/or other
steering members) spaced circumferentially apart around a perimeter
of the RSS module; and a valve operable to sequentially actuate the
steering pads; and operating a controller to independently actuate
the valve of each RSS module to, simultaneously: sequentially
actuate the steering pads of a first one of the RSS modules to
operatively urge the first one of the RSS modules in a first
azimuthal direction; sequentially actuate the steering pads of a
second one of the RSS modules to operatively urge the second one of
the RSS modules in a second azimuthal direction substantially
different from the first azimuthal direction; and sequentially
actuate the steering pads of a third one of the RSS modules to
operatively urge the third one of the RSS modules in a third
azimuthal direction substantially different from the second
azimuthal direction.
[0071] The second azimuthal direction may be substantially opposite
the first azimuthal direction, and the third azimuthal direction
may be substantially similar to the first azimuthal direction. The
first and third azimuthal directions may each be angularly offset
from the second azimuthal direction by an amount ranging between
about 175 degrees and about 185 degrees.
[0072] The method may further comprise operating the controller to
control the valves of the RSS modules to, simultaneously: actuate
the steering pads of the first one of the RSS modules to
operatively centralize the first one of the RSS modules within the
wellbore; actuate the steering pads of the second one of the RSS
modules to operatively centralize the second one of the RSS modules
within the wellbore; and sequentially actuate the steering pads of
the third one of the RSS modules to operatively urge the third one
of the RSS modules in an azimuthal direction away from a
longitudinal axis of the first and second ones of the RSS
modules.
[0073] The method may further comprise, prior to conveying at least
a portion of the apparatus within the wellbore, coupling the RSS
modules in series between the drill string and the drill bit.
[0074] The method may further comprise, prior to conveying at least
a portion of the apparatus within the wellbore: coupling a first
flexible component between first and second ones of the RSS
modules; and coupling a second flexible component between the
second one of the RSS modules and a third one of the RSS modules.
Each of the first and second components may comprise a joint.
[0075] Operating the controller may comprise operating the
controller while rotating the drill bit to extend the wellbore at a
dogleg of up to about twenty degrees per 100 feet (30.5
meters).
[0076] The foregoing outlines features of several embodiments so
that a person having ordinary skill in the art may better
understand the aspects of the present disclosure. A person having
ordinary skill in the art should appreciate that they may readily
use the present disclosure as a basis for designing or modifying
other processes and structures for carrying out the same purposes
and/or achieving the same advantages of the embodiments introduced
herein. A person having ordinary skill in the art should also
realize that such equivalent constructions do not depart from the
scope of the present disclosure, and that they may make various
changes, substitutions and alterations herein without departing
from the spirit and scope of the present disclosure.
[0077] The Abstract at the end of this disclosure is provided to
comply with 37 C.F.R. .sctn.1.72(b) to allow the reader to quickly
ascertain the nature of the technical disclosure. It is submitted
with the understanding that it will not be used to interpret or
limit the scope or meaning of the claims.
* * * * *