U.S. patent application number 13/048595 was filed with the patent office on 2012-09-20 for timed steering nozzle on a downhole drill bit.
Invention is credited to Scott Dahlgren, David R. Hall, Jonathan Marshall.
Application Number | 20120234604 13/048595 |
Document ID | / |
Family ID | 46827571 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120234604 |
Kind Code |
A1 |
Hall; David R. ; et
al. |
September 20, 2012 |
Timed Steering Nozzle on a Downhole Drill Bit
Abstract
In one aspect of the present invention, a downhole rotary
steerable system comprises a fluid path defined by a bore formed
within a drill string component. A valve located within a wall of
the bore which hydraulically connects the bore with a fluid cavity.
A steering nozzle disposed on the drill string component and in
communication with the fluid cavity. The valve is configured to
control flow from the bore to the fluid cavity with an azimuthal
sensing mechanism configured to determine the azimuth of the
steering nozzle and instrumentation configured to control the valve
based off of input from the azimuthal sensing mechanism.
Inventors: |
Hall; David R.; (Provo,
UT) ; Marshall; Jonathan; (Provo, UT) ;
Dahlgren; Scott; (Alpine, UT) |
Family ID: |
46827571 |
Appl. No.: |
13/048595 |
Filed: |
March 15, 2011 |
Current U.S.
Class: |
175/73 |
Current CPC
Class: |
E21B 10/602 20130101;
E21B 7/064 20130101 |
Class at
Publication: |
175/73 |
International
Class: |
E21B 7/04 20060101
E21B007/04 |
Claims
1. A downhole rotary steerable system, comprising: a fluid path
defined by a bore formed within a drill string component; a valve
located within a wall of the bore and which hydraulically connects
the bore with a fluid cavity; a steering nozzle disposed on the
drill string component and in communication with the fluid cavity;
the valve is configured to control flow from the bore to the fluid
cavity; an azimuthal sensing mechanism configured to determine an
azimuth of the steering nozzle; and instrumentation configured to
control the valve based off of an input from the azimuthal sensing
mechanism.
2. The system of claim 1, wherein the azimuthal sensing mechanism
comprises a plurality of accelerometers configured to transmit a
signal to the instrumentation that actuates the valve through use
of a motor.
3. The system of claim 2, wherein the azimuthal sensing mechanism
comprises at least one magnetometer that measures the azimuthal
position, wherein the azimuthal sensing mechanism is configured to
calibrate the valve using the input from the magnetometer.
4. The system of claim 1, further comprising at least one
expandable element supported by the drill string component and in
communication with at least one fluid cavity.
5. The system of claim 4, wherein the at least one expandable
element is disposed opposite the steering nozzle on the drill
string component.
6. The system of claim 4, wherein a diameter of the steering nozzle
is smaller than a diameter of the valve such that a pressure
differential is created that forces the expandable element to
extend.
7. The system of claim 6, wherein the pressure differential results
in ejecting a fluid at a formation with increased force.
8. The system of claim 4, wherein the expandable element is
configured to shift a center axis of the drill string away from a
center axis of the borehole.
9. The system of claim 4, wherein each expandable element and
steering nozzle is in fluid communication through a separate fluid
cavity.
10. The system of claim 1, further comprising a plurality of valves
with each valve in fluid communication with a steering nozzle and
expandable element.
11. The system of claim 10, wherein the instrumentation is
configured to actuate each valve separately.
12. The system of claim 1, wherein the valve is configured to be
actuated by a motor powered by a turbine generator.
13. The system of claim 1, wherein a turbine generator is
configured to power the azimuthal sensing mechanism.
14. The system of claim 1, further comprising at least one drilling
nozzle disposed on a working face of a drill bit attached to the
drill string component.
15. The system of claim 14, wherein the drilling nozzle is
configured to clean the blades of a drill bit and remove debris
from the working face of the drill bit.
16. The system of claim 14, wherein the valve is configured to
regulate fluid between the bore, fluid cavity, and at least one
drilling nozzle.
17. The system of claim 1, wherein the valve, azimuth sensing
mechanism, and instrumentation are disposed within a housing.
18. The system of claim 17, wherein the housing is inserted into
the bore of the drill string component.
19. The system of claim 17, wherein the fluid cavity comprises an
annular shape between the housing and the drill string component.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the field of steering
assemblies used for downhole directional drilling. The prior art
discloses directional drilling drill bit assemblies.
[0002] U.S. Pat. No. 5,553,678 to Barr et al., which is herein
incorporated by reference for all that it contains, discloses a
modulated bias unit is provided for controlling the direction of
drilling of a rotary drill bit when drilling boreholes in
subsurface formations. The unit comprises a plurality of hydraulic
actuators spaced apart around the periphery of the unit and having
movable thrust members hydraulically displaceable outwardly for
engagement with the formation of the borehole being drilled. Each
actuator has an inlet passage for connection to a source of
drilling fluid under pressure and an outlet passage for
communication with the annulus. A selector control valve connects
the inlet passages in succession to the source of fluid under
pressure, as the unit rotates, and a choke is provided to create a
pressure drop between the source of fluid under pressure and the
selector valve. A further choke is provided in the outlet passage
from each actuator unit. The actuators and control valve
arrangements may take a number of different forms.
[0003] U.S. Pat. No. 4,416,339 to Baker et al., which is herein
incorporated by reference for all that it contains, discloses a
mechanism and method for positive drill bit guidance during well
drilling operations. The guidance device includes a control arm or
paddle which, due to hydraulic pressure, pivots to steer the drill
bit towards its target area. As the paddle applies pressure to the
wall of the well, the drill bit is then turned from the contacted
area of the well wall in the desired direction.
[0004] U.S. Pat. No. 5,582,259 to Barr et al., which is herein
incorporated by reference for all that it contains, discloses a
modulated bias unit, for controlling the direction of drilling of a
rotary drill bit when drilling boreholes in subsurface formations,
comprises a number of hydraulic actuators spaced apart around the
periphery of the unit. Each actuator comprises a movable thrust
member which is hydraulically displaceable outwardly and a
formation-engaging pad which overlies the thrust member and is
mounted on the body structure for pivotal movement about a pivot
axis located to one side of the thrust member. A selector control
valve modulates the fluid pressure supplied to each actuator in
synchronism with rotation of the drill bit so that, as the drill
bit rotates, each pad is displaced outwardly at the same selected
rotational position so as to bias the drill bit laterally and thus
control the direction of drilling. The pivot axis of the
formation-engaging member is inclined to the longitudinal axis of
rotation of the bias unit so as to compensate for tilting of the
bias unit in the borehole during operation.
BRIEF SUMMARY OF THE INVENTION
[0005] In one aspect of the present invention, a downhole rotary
steerable system comprises a fluid cavity defined by a bore formed
within a drill string component. A valve may be located within the
wall of the bore, which hydraulically connects the bore with the
fluid cavity. A steering nozzle may be disposed on the drill string
component and in communication with the fluid cavity. The valve is
configured to control flow from the bore to the fluid cavity and an
azimuthal sensing mechanism may be configured to determine the
azimuth of the steering nozzle. Instrumentation may be configured
to control the valve based off of input from the azimuthal sensing
mechanism.
[0006] The azimuthal sensing mechanism may comprise a plurality of
accelerometers configured to transmit a signal to the
instrumentation that actuates the valve through the use of a motor.
The azimuthal sensing mechanism may also comprise at least one
magnetometer which measures azimuth position, wherein the azimuthal
sensing mechanism is configured to calibrate the valve using the
input from the magnetometer. The steerable system may further
comprise at least one expandable element supported by the drill
string component and in communication with at least one fluid
cavity. The expandable element may be disposed opposite the
steering nozzle on the drill string element.
[0007] The diameter of the steering nozzle may be smaller than the
diameter of the valve such that a pressure differential is created
that forces the expandable element to extend and results in
ejecting the fluid through the steering nozzle at the formation
with increased force. The expandable element may be configured to
shift the center axis of the drill string away from the center axis
of the borehole. Each expandable element and steering nozzle may be
in fluid communication with a steering nozzle and expandable
element.
[0008] The instrumentation may be configured to actuate each valve
separately. The valve may be configured to be actuated by a motor
powered by a turbine generator. The turbine generator may also be
configured to power the azimuthal sensing mechanism. The valve,
azimuthal sensing mechanism, and instrumentation may be disposed
within a housing. The housing may be inserted into the bore of the
drill string component and the fluid cavity may comprise an annular
shape formed between the housing and the drill string
component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a perspective view of an embodiment of a drill
string suspended from a drill rig.
[0010] FIG. 2 is a perspective view of an embodiment of a steerable
system.
[0011] FIG. 3 is a perspective view of an embodiment of a steerable
system.
[0012] FIG. 4a is a perspective view of an embodiment of a
steerable system.
[0013] FIG. 4b is a cross-sectional view of an embodiment of a
steerable system.
[0014] FIG. 5a is a cross-sectional view of an embodiment of a
steerable system.
[0015] FIG. 5b is a cross-sectional view of an embodiment of a
steerable system.
[0016] FIG. 6 is a cross-sectional view of an embodiment of a
steerable system.
[0017] FIG. 7 is a perspective view of another embodiment of a
steerable system.
[0018] FIG. 8 is a cross-sectional view of another embodiment of a
steerable system.
[0019] FIG. 9 is a perspective view of another embodiment of a
steerable system.
[0020] FIG. 10 is a cross-sectional view of another embodiment of a
steerable system.
[0021] FIG. 11a is a cross-sectional view of another embodiment of
a steerable system.
[0022] FIG. 11b is a cross-sectional view of another embodiment of
a steerable system.
[0023] FIG. 12a is a cross-sectional view of another embodiment of
a steerable system.
[0024] FIG. 12b is a cross-sectional view of another embodiment of
a steerable system.
[0025] FIG. 13a is a cross-sectional view of an embodiment of a
retraction mechanism.
[0026] FIG. 13b is a cross-sectional view of another embodiment of
a retraction mechanism.
DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED
EMBODIMENT
[0027] Referring now to the figures, FIG. 1 is a perspective view
of an embodiment of a drilling operation comprising a downhole tool
string 100 suspended by a derrick 101 in a wellbore 102. A
steerable system 103 may be located at the bottom of the wellbore
102 and may comprise a drill bit 104. As the drill bit 104 rotates
downhole, the downhole tool string 100 advances farther in to the
earth. The downhole tool string 100 may penetrate soft or hard
subterranean formations 105. The steerable system 103 may be
adapted to steer the drill string 100 in a desired trajectory. The
downhole tool string 100 may comprise electronic equipment capable
of sending signals through a data communication system to a
computer or data logging system 106 located at the surface.
[0028] FIG. 2 discloses a drill bit 104 with a plurality of fixed
blades 201. The fixed blades 201 may comprise a plurality of
cutters 203 such that as the drill string rotates the cutters
penetrate into the earthen formation. An expandable element 205 may
be disposed adjacent to the drill bit 104. The expandable element
205 may extend away from the axis of the drill string into an
earthen formation shifting the axis of the drill string away from
the axis of the borehole.
[0029] FIG. 3 discloses a steering nozzle 301 disposed adjacent to
the working face of the drill bit 104 opposite the expandable
element 205. The steering nozzle 301 may be configured to direct
fluid away from the drill bit 104 and towards an earthen formation.
The drill bit 104 may comprise a plurality of fixed blades 201
evenly spaced on the working face. The blades 201 may comprise a
plurality of cutters 203 disposed on the blade 201. At least one
drilling nozzle 303 may be disposed between each fixed blade 201
and configured to direct fluid toward the plurality of cutters 203
removing excess cutting debris from the working face of the drill
bit 104.
[0030] FIGS. 4a and 4b are perspective and cross-sectional views of
another embodiment of a steerable system 103. The system 103 may
comprise an expandable element 205 disposed on a drill string 100
attached to a drill bit 104. The drill string 100 may comprise a
generally outer annular surface, and the steering nozzle 301 and
the expandable element 205 may both be supported by the generally
outer annular surface, but positioned opposite each other. In some
embodiments the steering nozzle may be disposed on a gauge of a
drill bit.
[0031] A housing 401 that contains some of the mechanism in the
steering system may be inserted into the bore of the drill string
100. O-rings 403 may provide a fluid seal between the housing 401
and the inner surface of the drill string's bore. The housing 401
may comprise a cylindrical geometry (or another geometry
complimentary to the inner surface of the bore). The thickness of
the housing wall may comprise a motor 405 to operate a valve 407,
the valve 407, an orientation sensing mechanism instrumentation
409, and part of an expandable element 205. The orientation sensing
mechanism may comprise instrumentation that determines the azimuth
of the drill string component. The orientation/azimuthal sensing
mechanism may comprise an accelerometer 411 and a magnetometer
413.
[0032] The expandable element 205 may extend through an opening in
a side of the drill string 100. The opening in the drill string may
correspond with an opening in the housing. As fluid is directed
towards a surface 449 on a back end 450 of the expandable element
205, the fluid cavity may be pressurized and fluid pressure may
exert a force on the surface 449 of the back end 450 to extend the
expandable element 205. Seals 451 disposed between the opening wall
and the expandable element may prevent leaks. In some embodiments,
a small leak is acceptable to keep debris from clogging the
interference between the expandable element and the opening. Also,
a stopping mechanism may be incorporated into the present invention
to retain the expandable element within the opening while allowing
the expandable element to translate within the opening.
[0033] The motor 405 may be mechanically connected to the valve
407. The instrumentation 409 may be in electrical communication
with the motor 405, and thus, control the valve. In the present
embodiment, the orientation sensing mechanism may be an azimuthal
sensing mechanism configured to detect the orientation of the drill
bit 104 downhole and transmit that data to the instrumentation 409
through the use of at least one accelerometer and magnetometer 411,
413. A processing element of the instrumentation 409 may compute
when to activate the motor 405 based on this downhole data or from
a separate input received from the surface.
[0034] Accelerometers may be used to track the azimuth of the
nozzle and expandable element. In some embodiments, a magnetometer
may be used to compensate for rotational drift defined as a
gradually increasing inconsistency between the accelerometer
readings and the actual location of the nozzles and expandable
element. The instrumentation 409 may be configured to compensate
for timing delays between the acquisition of data and actuation of
the valve as well as the delay between the actuation of the valve
and the actuation of the expandable element, thus, facilitating a
more precise change in direction while drilling.
[0035] FIGS. 5a and 5b are cross-sectional views of an embodiment
of a steerable system 103. FIG. 5a discloses the steerable system
103 with the valve 407 closed. The closed valve 407 results in all
drilling fluid being directed to the drilling nozzles 303 in the
working face of the drill bit 104. FIG. 5b discloses the valve 407
open and directing a portion of the drilling fluid into the fluid
cavity 501, and thus, to the steering nozzle 301 and expandable
element 205.
[0036] The valve 407 may comprise a plurality of ports 505
configured to direct fluid from the bore 503 of the drill string to
the compressible fluid cavity 501. The ports 505 may be aligned
with the bore 503 through the use of a motor 405. As the motor 405
rotates the valve 407, the ports 505 may open and close to the bore
503. When open, the valve directs a portion of the drilling fluid
from the bore 503 and into the compressible fluid cavity 501. The
valve 407 may be a rotary valve, ball valve, butterfly valve, or
any valve that can be used to regulate fluid.
[0037] The fluid may enter the compressible fluid cavity 501 and be
directed to a steering nozzle 301 and an expandable element 205.
The path to the expandable element 205 may comprise a larger cross
sectional area than the steering nozzle 301, thus, directing more
fluid to the expandable element 205 than to the steering nozzle
301. In some embodiments, the back end of the expandable element
may comprise a greater area than the opening in the steering
nozzle. The expandable element 205 may come into contact with the
earthen formation directing the drill string in the opposite
direction of the earthen formation while forcing more fluid through
the steering nozzle 301. The steering nozzle 301 may comprise a
smaller diameter than the ports 505 creating a greater pressure
differential in the compressible fluid cavity 501 from the
restriction of fluid passing through the steering nozzle 301. The
greater pressure differential may result in the fluid from the
steering nozzle 301 being directed at a greater velocity than the
fluid from the drilling nozzles 303.
[0038] FIG. 6 is a cross-sectional view of an embodiment of a
steerable system 103. The cross-section discloses the expandable
element 205 in fluid communication with the valve 407 through the
compressible fluid cavity 501. The steering nozzle may be disposed
on the opposite side of the drill string from the expandable
element. Preferably, when the valve is open to the drilling fluid
in the drill string's bore, the fluid is in fluid communication
with both the steering nozzle and the back end of the expandable
element at the same time. The compressible fluid cavity from the
valve to the back end of the expandable element may form a circular
geometry. In some embodiments, the cavity is formed radially to the
bore and provides multiple routes to the expandable element. In
some embodiments, the cavity is formed between an outer surface of
the housing (shown in FIG. 4b) and the inner surface of drill
string. In part the bore may be formed by the housing. The
expandable element 205 may comprise at least one O-ring 601 forming
a fluid seal between the expandable element 205 and any fluids
outside the drill string
[0039] FIG. 7 is a perspective view of a steerable system 103
disposed within a borehole formed in an earthen formation 105 with
a first axis of rotation 701. As fluid flows through the fluid
cavity, the expandable element 205 may extend toward the earthen
formation 105 while fluid is being directed at the earthen
formation 105 through the steering nozzle 301 on the opposite side
of the expandable element 205. As the expandable element 205
extends and makes contact with the earthen formation 105 the axis
of rotation may shift to a second axis 703. Fluid may continue to
exit through the drilling nozzles and mix with the fluid from the
steering nozzle 301. The fluid from the steering nozzle 301 may
exit at a greater velocity than the fluid from the drilling, face
nozzles, thus, directing the force of drilling fluid into a portion
of the formation's wall forming an eroded area 705, and the
expandable element is configured to urge the drill into the eroded
area 705.
[0040] FIG. 8 is a cross-sectional view of another embodiment of a
steerable system 103. The system may comprise an expandable element
205 comprising a ring 801 disposed around the outer diameter of the
drill string 100. The ring 801 may comprise a single, continuous
body and be in mechanical connection with a billows, an inflatable
bladder, a piston, a ball, or combinations thereof. In the present
embodiment, the ring 801 is in mechanical communication with a
piston 803. The piston 803 may be disposed in the fluid cavity 501
such that the fluid in the cavity may actuate the piston 803, thus,
extending the ring 801 away from the drill string.
[0041] FIG. 9 is a perspective view of another embodiment of a
steerable system 103. The system may comprise a plurality of
drilling face nozzles 901 disposed on the working face of the drill
bit and a plurality of steering nozzles 903 disposed on the side of
the drill bit 104. A plurality of expandable elements 905 may be
disposed evenly around the circumference of the drilling string
adjacent to the drill bit 104. Each steering nozzle 903 may be
configured to direct drilling fluid independently of each other
steering nozzle 903. Each steering nozzle 903 may be in fluid
communication with a separate compressible fluid cavity. Each
expandable element 905 may be disposed directly across from a
steering nozzle 903 and be in fluid communication with said nozzle
through a compressible fluid cavity. Each pair of steering nozzles
and expandable element may function together at specific moments to
change the trajectory or steer the drill string. A control board
may be configured to synchronize the steering nozzles 901 and
expandable elements 903 to activate while in the same direction
while drilling thus increasing the speed at which a direction can
be changed while drilling. The compressible fluid cavities for each
pair of expandable elements and steering nozzles may be independent
of the other cavities. In some embodiments, switches may provide
some intentional fluid communication between the cavities.
[0042] FIG. 10 is a cross-sectional view of another embodiment of a
steerable system 103. The system discloses a generator 1001
disposed within the bore 503 of the drill string 100. The generator
1001 may be configured to provide power to the motor 405 and the
control board 409.
[0043] FIGS. 11a and 11b are cross-sectional views of another
embodiment of a steerable system 103. The system 103 may comprise a
reciprocating valve 1101 configured to direct all fluid to the at
least one steering nozzle 301 disposed on the side of the drill bit
104 or to direct all drilling fluid to the at least one drilling
nozzle 303 disposed on the working face of the drill bit 104.
[0044] FIG. 11a discloses the valve 1101 open to the bore of the
drill string and directing fluid to the expandable element and the
steering nozzle. However, the geometry of the valve also
simultaneously blocks fluid from the face, drilling nozzles. Thus,
while the fluid is directed to the steering nozzles, the fluid is
also temporarily blocked to the face, drilling nozzles. Such an
arrangement many provide at least two advantages. First, more
hydraulic power may be provided to the steering nozzle and
expandable element. Second, the fluid ejected from the face,
drilling nozzles may have a lower propensity to interfere with the
fluid ejected from the steering nozzle. Third, the temporary
blockage may induce a vibration in the fluid ejected from the face,
drilling nozzles, which may provide an additional destructive force
into the formation. FIG. 11b discloses the valve 1101 closed to the
bore and thus, directing the fluid to the drilling nozzles 303.
[0045] FIGS. 12a and 12b disclose a reciprocating valve 1201
configured to alternate drilling fluid between a fluid cavity 501,
and thus to the steering nozzle and expandable element, and to a
single drilling nozzle 1203 disposed nearby the steering nozzle
301. FIG. 12a discloses the valve directing fluid to the fluid
cavity 501 while blocking the fluid flow to the drilling nozzle.
FIG. 12b, on the other hand, discloses the valve 1201 directing
fluid to the drilling nozzle 1203 while blocking the fluid to the
steering nozzle 301.
[0046] FIGS. 13a and 13b disclose a retraction mechanism 1301
disposed adjacent an expandable element 1303. The retraction
mechanism 1301 may comprise a compression spring, a tension spring,
a spring mechanism, or a hydraulic mechanism. FIG. 13a discloses a
spring mechanism 1305 retracting the expandable element as the
valve 407 closes and fluid pressure in the fluid cavity is
reduced.
[0047] FIG. 13b discloses a retraction mechanism 1301 comprising a
hydraulic mechanism 1307. As the valve 407 closes, fluid may be
directed into a hydraulic chamber 1307 that, when pressurized,
returns the expandable element to its retracted position.
[0048] Whereas the present invention has been described in
particular relation to the drawings attached hereto, it should be
understood that other and further modifications apart from those
shown or suggested herein, may be made within the scope and spirit
of the present invention.
* * * * *