Note: Descriptions are shown in the official language in which they were submitted.
CA 02780351 2012-06-14
FLOW OPERATED ORIENTER
BACKGROUND OF THE INVENTION
Field of the Invention
Embodiments of the present invention generally relate to a flow operated
orienter.
Description of the Related Art
Conventional directional drilling with a drillstring of jointed pipe is
accomplished through use of a Bottom Hole Assembly (BHA) including a bent sub
(typically one-half to three degrees), a drilling or mud motor, and
directional
Measurement While Drilling (MWD) tool in the following fashion. To drill a
curved
wellbore section, the drillstring is held rotationally fixed at the surface
and the drilling
motor will drill a curved wellbore in the direction or orientation of the bent
sub. This is
termed slide drilling because the entire drillstring slides along the wellbore
as drilling
progresses. The wellbore trajectory is controlled by orienting the BHA in the
desired
direction by rotating the drillstring the appropriate amount at the surface.
To drill a straight wellbore section, the drillstring is rotated at the
surface with
the rotary table or top-drive at some nominal rate, typically 60 to 90 rpm.
This is termed
rotary drilling. In so doing, the tendency of the mud motor to drill in a
particular
direction, due to the bent sub, is overridden by the superimposed drillstring
rotation
causing the drilling assembly to effectively drill straight ahead.
When drilling with coiled tubing, neither rotary drilling nor rotational
orientation of the BHA can be accomplished without the addition to the BHA of
a special
rotating device to orient the BHA since coiled tubing cannot be rotated in the
wellbore
from the surface. One such rotational device, or orienter, operates by
rotating in even
angular increments, for example 30 , each time the surface pumps are stopped
and
then re-started. After each pump cycle, the orienter locks into and maintains
its
rotational position. This ratcheting device allows the directional driller to
position the
directional assembly closely enough to the desired toolface orientation to
allow the
wellbore to be drilled in a particular direction.
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One drawback to directional drilling with the ratcheting orienter relates to
its
inability to drill an effective straight wellbore section. As discussed above,
in
conventional directional drilling, continuous drillstring rotation is used to
negate the
directional tendency of a bent-housing motor. This produces a very straight
trajectory.
When drilling with coiled tubing and a ratcheting orienter, continuous
rotation is not
possible. Thus the driller is forced to orient slightly left of the desired
path and drill some
distance ahead. Then after stopping to re-orient right of the desired path,
the driller
drills ahead again. This process is repeated until the "straight" section is
completed.
The resulting left-right-left or "wig-wag" wellbore trajectory roughly
approximates the
desired straight path.
For illustration and a more detailed discussion of rotary and sliding
drilling,
see U.S. Pat. No. 6,571,888.
SUMMARY OF THE INVENTION
Embodiments of the present invention generally relate to a flow operated
orienter. In one embodiment, a bottom hole assembly (BHA) for use in drilling
a
wellbore includes: a first mud motor having a stator and a rotor; a second mud
motor
having a stator and a rotor; a drill bit rotationally coupled to the second
rotor and having
a tool face and a longitudinal axis inclined relative to a longitudinal axis
of the first mud
motor; and a clutch. The clutch is operable to: rotationally couple the second
stator to
the first stator in a first mode at a first orientation of the tool face,
rotationally couple the
first rotor to the second stator in a second mode, change the first
orientation to a
second orientation by a predetermined increment, orient the tool face at the
second
orientation in an orienting mode, and shift among the modes in response to a
change in
flow rate of a fluid injected through the clutch and/or a change in weight
exerted on the
drill bit.
In another embodiment, a clutch includes: a tubular housing; a rotary shaft
disposed in the housing; a rotary jaw rotationally coupled to the rotary
shaft; an output
shaft disposed in the housing; an output jaw rotationally coupled to the
output shaft and
having an asymmetric jaw face; and an orienting jaw having an asymmetric jaw
face.
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The clutch is fluid operable among: a rotary mode, wherein the rotary and
output jaws
are engaged, thereby rotationally coupling the rotary and output shafts, a
sliding mode,
wherein the asymmetric jaw faces are engaged and the orienting jaw is
rotationally
coupled to the housing, thereby rotationally coupling the output shaft and the
housing,
and an orienting mode, wherein the rotary and output jaws are disengaged, the
asymmetric jaw faces are contacting and misaligned, and the orienting jaw is
rotationally coupled to the housing.
In another embodiment, a method of directional drilling a wellbore, includes
injecting drilling fluid through a coiled tubing string extending from the
surface and into
the wellbore and a bottom hole assembly (BHA) disposed in the wellbore and
connected to an end of the coiled tubing string. The BHA includes a BHA motor,
a drill
bit motor, a drill bit having a tool face and a longitudinal axis inclined
relative to a
longitudinal axis of the BHA motor, and a clutch. The clutch engages the BHA
motor
with the bit motor in a rotary mode, thereby rotating the bit motor. The bit
motor rotates
the drill bit, thereby drilling the wellbore. The method further includes
shifting the clutch
to a sliding mode. The clutch: allows reactive rotation of the bit motor until
the tool face
is at a first orientation, rotationally couples the bit motor to the coiled
tubing string at the
first orientation, and disengages the BHA motor from the bit motor. The method
further
includes slide drilling the wellbore at the first orientation.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the present
invention can be understood in detail, a more particular description of the
invention,
briefly summarized above, may be had by reference to embodiments, some of
which
are illustrated in the appended drawings. It is to be noted, however, that the
appended
drawings illustrate only typical embodiments of this invention and are
therefore not to
be considered limiting of its scope, for the invention may admit to other
equally effective
embodiments.
Figure 1 is a diagram of a coiled tubing Bottom Hole Assembly (BHA),
according to one embodiment of the present invention.
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Figures 2A-2F are longitudinal sectional views of the orienter of Figure 1.
Figures 3A-3C are isometric views illustrating the clutch subassembly of the
orienter in a neutral position.
Figures 4A-4D are isometric side-by-side views comparing a portion of the
clutch subassembly in rotary mode (Figures 4A and 4C) and sliding mode
(Figures 4B
and 4D).
Figures 5A and 5B are isometric views illustrating a portion of the clutch
subassembly in the orienting mode. Figure 5C is an isometric view illustrating
the
asymmetric jaw face of the orienting cam/jaw.
Figure 6A is a table illustrating surface indicators for determining which
mode
the orienter is in.
Figure 6B is a flow chart illustrating a method for determining which
operational mode the orienter is currently in.
Figure 6C is a flowchart illustrating a method for switching the orienter from
the sliding mode to the rotary mode.
Figure 6D is a flowchart illustrating a method for switching the orienter from
the rotary mode to the sliding mode.
Figure 6E is a flowchart illustrating a method for changing the tool face
setting of the orienter.
DETAILED DESCRIPTION
Figure 1 is a diagram of a coiled tubing Bottom Hole Assembly (BHA) 100,
according to one embodiment of the present invention. The coiled tubing BHA
100 may
include: a drill bit 105, a first mud motor (or bit motor) 110, measurement
while drilling
(MWD) module 115, orienter 200, and an adapter 125. The bit motor 110 may
harness
fluid energy from drilling fluid by channeling it between a profiled rotor and
stator,
thereby imparting the energy into rotational motion of the rotor. The bit
motor 110 may
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be a positive displacement motor (PDM), such as a Moineau motor, or a
turbomachine,
such as a centrifugal, axial flow, or mixed flow motor.
The drill bit 105 may be longitudinally and rotationally coupled to the rotor
of
the bit motor 110, such as by a threaded connection. The stator of the bit
motor 110
may be disposed in and longitudinally and rotationally coupled to a housing of
the bit
motor 110. The rotor of the bit motor 110 may be disposed in the housing of
the bit
motor 110 and longitudinally coupled thereto by one or more bearings. The
housing of
the bit motor 110 may be bent, thereby inclining a longitudinal axis of the
drill bit 105
and a lower portion 11 Ob of the bit motor 110 relative to a longitudinal axis
of the rest of
the BHA 200 at a predetermined angle, such as one-half to three degrees. When
rotated by the orienter 200, this inclination may cause eccentric rotation of
a tool face
TF of the drill bit 105, the drill bit 105, and/or the bent portion 110b. The
bit motor 110
rotor may rotate the bit 105 when powered by drilling fluid and the bent
housing may
effect drilling in a curved direction when the bent housing is rotationally
fixed. The bent
housing may be longitudinally and rotationally coupled to the MWD module 115,
such
as by a threaded connection. Alternatively, a bent sub (not shown) may be
longitudinally and rotationally coupled to a straight housing bit motor, such
as by a
threaded connection. Alternatively, the BHA 100 may be deployed with a string
of drill
pipe instead of coiled tubing 130.
The MWD module 115 may be longitudinally and rotationally coupled to a
rotor of the orienter 200, such as by a threaded connection. MWD module 115
may
include one or more sensors, such as a magnetometer and/or an accelerometer,
to
measure borehole inclination and/or direction and may further include a
wireless
transmitter, such as a mud pulser, to transmit the measurements to the
surface. The
MWD module 115 may further include a power source, such as a fluid operated
generator and/or a battery. The adapter 125 may be longitudinally and
rotationally
coupled to a stator or housing of the orienter 200, such as by a threaded
connection.
The adapter 125 may be longitudinally and rotationally coupled to a string of
coiled
tubing 130, such as with a flange or union.
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The BHA 100 may also include a pressure and/or temperature (PT) module
for monitoring bottomhole pressure and/or temperature. The PT measurements may
be transmitted to the surface using the mud pulser. The BHA 100 may further
include
an LWD module (not shown). The LWD module may include one or more instruments,
such as spontaneous potential, gamma ray, resistivity, neutron porosity, gamma-
gamma/formation density, sonic/acoustic velocity, and caliper. Raw data from
these
instruments may be transmitted to the surface using the mud pulser. The raw
data may
be processed to calculate one or more formation parameters, such as lithology,
permeability, porosity, water content, oil content, and gas content as a
formation is
being drilled through (or shortly thereafter). Alternatively, instead of a mud
pulser, the
MWD, PT, and/or LWD data may be transmitted via a conductor embedded in the
coiled tubing string or electromagnetic (EM) telemetry. The conductor may also
provide
power to the MWD, PT, and/or LWD modules.
Figures 2A-2F are longitudinal sectional views of the orienter 200. The
orienter 200 may include a motor sub-assembly M, an upper bearing subassembly
UB,
a clutch subassembly C, and a lower bearing subassembly LB. The motor sub-
assembly M may include a second (or BHA) mud motor 201 (any of the types,
discussed above, PDM as shown) and an articulator 202, 203. An upper
longitudinal
end of the stator/housing 201s of the BHA motor 201 may be longitudinally and
rotationally coupled to the adapter 125, such as with a threaded connection.
The lower
bearing subassembly LB may include an output shaft 230 longitudinally and
rotationally
coupled to the MWD module 115, such as with a threaded connection.
The orienter 200 may include three operating modes: rotary drilling mode,
sliding drilling mode, and orienting mode and two shifting positions: neutral
and bypass.
In the rotary mode, the clutch C may rotationally couple the BHA rotor 201r to
the
output shaft 230, thereby rotating the bent housing 110 (continuously changing
the tool
face TF orientation) and negating the curved propensity imparted by the bent
housing
110. In the sliding mode, the clutch C may rotationally couple the output
shaft 230 to a
stator or housing of the orienter 200, such as jaw housing 219, thereby
rotationally
fixing the bent housing 110 at a particular setting or orientation and
allowing the bent
housing 110 to impart curvature to the drilling path of the bit 105. The
shifting positions
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may each be used to shift the clutch C between the rotary and sliding modes.
If the
clutch C is shifted between rotary and sliding modes using the neutral
position, then the
tool face setting or orientation may be changed by a predetermined angular
increment.
The predetermined angular increment may range from five to forty-five degrees,
such
as thirty-six degrees. If the clutch C is shifted between rotary and sliding
modes using
the bypass position, then the tool face setting or orientation may not be
changed.
When shifting from the rotary mode to the sliding mode, the clutch C may enter
the
orienting mode either to restore a previous tool face setting or to enter a
new tool face
setting depending on the shifting position employed. In the orienting mode,
the clutch C
may allow the output shaft 230 to be rotated by reaction torque from the bit
motor 110
until the tool face TF setting is achieved and then shift into sliding mode at
the tool face
setting TF.
Operation of the orienter 200 among the three modes may be accomplished
using a pressure differential between higher pressure drilling fluid 250f
injected through
the orienter 200 and lower pressure drilling fluid (and cuttings, collectively
returns 250r)
returning from the drill bit 105 to the surface via an annulus formed between
an outer
surface of the coiled tubing string 130 and the BHA 100 and an inner surface
of the
wellbore. The pressure differential between the drilling fluid 250f and
returns 250r may
be controlled by controlling an injection rate of a rig mud pump (not shown)
and/or
controlling weight exerted on the drill bit 105 by controlling a lifting force
exerted by the
drilling rig (not shown) on the coiled tubing string 130. Decreasing the
injection rate of
the drilling fluid 250f may decrease the pressure differential and vice versa.
Decreasing
a weight exerted on the drill bit 105 may decrease the pressure differential
and vice
versa. Other factors that may affect differential pressure are drilling fluid
properties
(i.e., density), drill bit motor pressure drop, coiled tubing string pressure
drop, and drill
bit pressure drop.
The articulator may include a shaft 202 and a housing 203. An upper
longitudinal end of the articulator shaft 202 may be longitudinally and
rotationally
coupled to a lower longitudinal end of the BHA rotor 201r, such as by a
threaded
connection, and a lower longitudinal end of the articulator shaft 202 may be
longitudinally and rotationally coupled to the crossover shaft 205, such as by
a threaded
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connection. The articulator shaft 202 may include sub-shafts longitudinally
and
rotationally coupled to one another by one or more articulating joints (not
shown see
`888 Patent), such as universal joints or constant velocity joints. The
articulating joints
may convert eccentric rotation of the BHA rotor 201 r to concentric rotation.
The
articulating joints may also accommodate bending of the orienter stator.
Alternatively, if
a turbo-motor is used instead of the PDM 201, the articulator 202, 203 may be
replaced
by a speed reducing gearbox. The articulator shaft 202 may further include a
balance
port 202p providing fluid communication between an annulus, formed between the
articulator shaft 202 and the articulator housing 203, and a bore of the
crossover shaft
205.
An upper longitudinal end of the articulator housing 203 may be longitudinally
and rotationally coupled to a lower longitudinal end of the BHA stator/housing
201s,
such as by a threaded connection, and a lower longitudinal end of the
articulator
housing 203 may be longitudinally and rotationally coupled to an upper
longitudinal end
of the crossover housing 206, such as by a threaded connection. The
articulator
housing 203 may include a recessed outer surface 203r extending along a
portion
thereof relative to an outer surface of the rest of the orienter stator. The
recessed outer
surface 203r may accommodate flexing of the orienter stator. The articulator
housing
203 may further include a bearing surface, such as longitudinal splines 203s,
extending
from an inner surface thereof. The splines 203s may provide radial support for
the
articulator shaft 202.
The upper bearing subassembly UB may include a balance piston 204, the
crossover shaft 205, the crossover housing 206, one or more bearings 207,
209u, 2091,
an upper bearing housing 208, and an upper portion of a rotary shaft 214. A
lower
longitudinal end of the crossover shaft 205 may be longitudinally and
rotationally
coupled to an upper longitudinal end of the rotary shaft 214, such as by a
threaded
connection. The balance piston 204 may be disposed in the crossover shaft
bore. The
balance piston 204 and a portion of the crossover shaft 205 below the balance
piston
may define a lubricant reservoir 205r. The balance piston 204 may equalize
fluid
pressure of the drilling fluid 250f from the balance port 202p with fluid
pressure of a
liquid lubricant, such as clean oil 250o, and include one or seals engaging an
inner
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surface of the crossover shaft 205 and isolating drilling fluid 250f from the
lubricant
250o. The balance piston 204 may longitudinally move relative to the crossover
shaft
205, thereby allowing the reservoir 205r to be variable.
The crossover shaft 205 may further include a drilling fluid crossover port
205d and a lubricant crossover port 2050. The drilling fluid crossover port
205d may
conduct drilling fluid 250f from an annulus, formed between the crossover
shaft 205 and
the crossover housing 206, to a bore of the rotary shaft 214. The lubricant
crossover
port 2050 may conduct lubricant 2500 between the reservoir 205r and an
annulus,
formed between the crossover shaft 205 and the upper bearing housing 208. One
or
more seals may be disposed between the crossover shaft 205 and the crossover
shaft
206 to isolate the crossover annulus from the rotary shaft-upper bearing
housing
annulus.
A lower longitudinal end of the upper bearing housing 208 may be
longitudinally and rotationally coupled to an upper longitudinal end of a
rotary housing
213. A radial bearing, such as a journal bearing 207, may be radially disposed
between
the upper bearing housing 208 and the crossover shaft 205 and longitudinally
disposed
between the lower longitudinal end of the crossover housing 206 and the upper
bearings 209u. One or more upper radial and/or thrust bearings 209u, such as a
rolling
element (i.e., ball) and a Michell bearing, may be disposed longitudinally
between a
lower longitudinal end of the bushing 207 and a shoulder 214s, extending from
an outer
surface of the rotary shaft 214, and radially between the rotary shaft 214 and
the upper
bearing housing 208. One or more lower radial and/or thrust bearings 2091,
such as
rolling element (i.e., ball) bearings, may be disposed longitudinally between
the
shoulder 214s and a shoulder, formed along an inner surface of the upper
bearing
housing 208, and radially between the rotary shaft 214 and the upper bearing
housing
208.
The clutch subassembly C may include the lower longitudinal end of the
upper bearing housing 208, a rotary cam 210, a rotary cam spring 211, a rotary
piston
212, a rotary housing 213, the rotary shaft 214, a radial bearing 215, a
rotary actuator
216, a rotary jaw 217, an output jaw 218, a jaw housing 219, an orienting
cam/jaw 220,
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an orienting piston 222, an orienting spring 223, a orienting shaft 224, an
orienting
housing 225, a rotary jaw spring 232, and a jaw shifter 233.
The rotary cam 210 may include a cam profile 210c (see Figure 3A), such as
a J-slot, formed in an outer surface thereof. A guide, such as a pin 234, may
be
fastened to the lower longitudinal end of the upper bearing housing 208 and
extend into
the J-slot 210c, thereby operably coupling the rotary cam 210 to the upper
bearing
housing 208. The rotary cam 210 may be longitudinally coupled to the rotary
piston
212, such as by a ball-groove connection 243b. The ball-groove connection 243b
and
a radial bearing, such as needle bearing 243a, may be radially disposed
between the
rotary piston 212 and the rotary cam 210 to allow the rotary cam 210 to rotate
relative
to the rotary piston 212. A lower longitudinal end of the rotary cam 210 may
form an
enlarged shoe 210s and the shoe may engage an inner surface of the rotary
housing
213, thereby radially coupling the rotary cam 210 and the rotary housing 213.
Rolling
elements, such as rollers 243c, may be disposed in an outer surface of the
rotary cam
210 so that the rotary cam 210 may freely rotate relative to the rotary
housing 213.
The shoe 210s may have a longitudinal lubricant port formed therethrough
allowing free flow of lubricant 2500. The shoe 210s may engage the lower
longitudinal
end of the upper bearing housing 208 in the neutral position. One or more keys
210k
(see Figure 3A) may extend from an outer surface of the rotary cam 210. The
keys
210k may engage corresponding keys extending from an inner surface of the
upper
bearing housing 208 in sliding mode and may engage keyways formed between the
upper bearing housing keys (and vice versa) in rotary mode.
The rotary cam 210 may also be disposed around the rotary piston 212. The
rotary piston 212 may include an upper sleeve portion 212us, a piston portion
212p,
and a lower sleeve portion 2121s. The rotary piston 212 may be disposed around
the
rotary shaft 214 such that an annulus may be formed between the rotary piston
212 and
the rotary shaft 214. The annulus may serve as a lubricant 250o conduit. An
upper
spring stop may be longitudinally coupled to the rotary piston 212, such as
with a
fastener (i.e., a snap ring). A lower spring stop may be longitudinally
coupled to the
cam housing 213, such as with engaging shoulders. The cam spring 211, such as
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coil spring or other biasing member, may be radially disposed between the
rotary
housing 213 and the rotary piston 212 and longitudinally abut the two stops,
thereby
biasing the rotary piston 212 longitudinally away from the rotary jaw 217.
The piston portion 212p may be an enlarged portion having an outer surface
engaging an inner surface of the rotary housing 213. One or more seals may be
disposed in the outer surface of the piston portion 212p and may isolate an
upper
longitudinal end from a lower longitudinal end. The upper longitudinal end may
be in
fluid communication with the lubricant reservoir 205r and the lower
longitudinal end may
be in fluid communication with the returns 250r via a radial port 236 formed
through a
wall of the rotary housing 213. The radial port 236 may have a filter fastened
therein,
such as with a threaded connection, for preventing entry of cuttings from the
returns
250r. A plug 235 may be longitudinally coupled to the rotary housing 213, such
as by a
threaded connection. One or more seals may be disposed in an outer surface of
the
plug 235 and one or more seals may be disposed in an inner surface of the plug
235.
The plug seals may isolate a lower piston chamber (in fluid communication with
the
returns 250r) from an annulus formed between the rotary piston 212 and the
rotary
housing 213 which may be in fluid communication with the lubricant reservoir
205r.
The rotary jaw spring 232 may longitudinally abut a lower longitudinal end of
the plug 235 and an upper longitudinal end of the rotary actuator 216, thereby
longitudinally biasing the rotary actuator 216 toward the output jaw 218. The
rotary jaw
spring 232 may be radially disposed between the cam housing 213 and the rotary
shaft
214 and/or rotary piston 212. The upper longitudinal end of the rotary
actuator 216 may
also receive a lower longitudinal end of the lower sleeve portion 2121s in
rotary mode.
The lower longitudinal end of the lower sleeve portion 2121s may have one or
more
notches formed radially therethrough providing lubricant communication in
rotary mode.
The lower longitudinal end of the rotary actuator 216 may abut a thrust
bearing 237.
The thrust bearing 237 may also abut an upper longitudinal end of the rotary
jaw 217,
thereby longitudinally coupling the rotary actuator 216 and the rotary jaw 217
while
permitting relative rotation therebetween. The rotary actuator 216 may be a
sleeve and
may include one or more windows radially formed through a wall thereof. The
radial
bearing 215 may be a journal bearing and include an outer journal
longitudinally and
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rotationally coupled to the cam housing and an inner journal longitudinally
and
rotationally coupled to the rotary shaft 214. The outer journal of the radial
bearing 215
may include one or more enlarged outer diameter portions extending through a
respective window of the rotary actuator 216 and a reduced diameter portion
radially
disposed between the rotary sleeve 216 and the rotary shaft 214.
A recess may be formed in the upper longitudinal end of the rotary jaw 217.
A thrust bearing 238 may be disposed along the recess and longitudinally
between a
fastener of the rotary jaw 217 and an upper longitudinal end of the jaw
shifter 233. The
thrust bearing 238 may permit rotation of the rotary jaw 217 relative to the
jaw shifter
233. The rotary jaw 217 may be rotationally coupled to the rotary shaft 214
and free to
move longitudinally relative thereto, such as with a ball-spline connection
(balls not
shown). The rotary jaw 217 may include a jaw face 217j, such as a crown,
spiral, or
square, formed in the lower longitudinal end thereof. The jaw face 217j may
mesh with
a mating jaw face 218uj formed in an upper longitudinal end of the output jaw
218 in the
rotary mode, thereby rotationally coupling the rotary shaft 214 and the
orienting shaft
224. The jaw faces 217j, 218uj may be symmetric
A recess may be formed in a lower longitudinal end of the rotary shaft 214.
An upper longitudinal end of the orienting shaft 224 may be received by the
rotary shaft
recess. A radial bearing 240, such as a needle bearing, may be radially
disposed
between the lower longitudinal end of the rotary shaft 214 and the upper
longitudinal
end of the orienting shaft 214 for permitting relative rotation therebetween
(in sliding
mode) and one or more seals may also be disposed therebetween for isolating
the
drilling fluid 250f from the lubricant 250o. One or more lubricant ports may
be radially
formed through the lower longitudinal end of the rotary shaft 214.
The output jaw 218 may be longitudinally and rotationally coupled to the
orienting shaft 224. The output jaw 218 may include a lower splined portion, a
central
shoulder, and an upper recessed portion. The orienting shaft 224 may include a
splined portion mating with the splined portion of the output jaw 218, thereby
rotationally coupling the orienting shaft and the output jaw. The orienting
shaft 224 may
include a tapered shoulder formed along an outer surface thereof proximately
below the
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splined portion for abutting the splines of the output jaw 218. The orienting
shaft 224
may further include a threaded portion proximately above the splined portion
for
receiving one or more threaded fasteners, such as nuts 241. The nuts 241 may
abut
the shoulder portion of the output jaw 218, thereby longitudinally coupling
the orienting
shaft 224 and the output jaw 218. The recessed portion of the output jaw 218
may
receive the lower longitudinal end of the rotary shaft 214.
A lower longitudinal end of the rotary housing 213 may be longitudinally and
rotationally coupled to an upper longitudinal end of the jaw housing 219, such
as with a
threaded connection. The jaw housing 219 may include a splined portion 219s
formed
along an inner surface thereof. The jaw shifter 233 may be rotationally
coupled to the
jaw housing 219. The jaw shifter 233 may include an upper sleeve portion 233s
and a
lower collet portion 233c. The lower collet portion 233c may include one or
more
fingers and each finger may be disposed between splines of the splined portion
219s,
thereby rotationally coupling the jaw shifter 233 and the jaw housing 219. The
splined
portion 219s may also serve as a longitudinal stop for the upper sleeve
portion 233s in
neutral position (the jaw shifter 233 may longitudinally float between the
thrust bearing
238 and the stop in the neutral position, see Figure 3B). A radial bearing
239, such as
a journal, may be radially disposed between the output jaw 218 and the collet
portion
233c/splined portion 219s. The radial bearing 239 may allow rotation of the
output jaw
219 relative to the collet portion 233c/splined portion 219s in rotary mode.
The orienting cam/jaw 220 may include a jaw face 220j, a cam profile 220c
(see Figure 3B), and one or more splines 220s. The splines 220s may extend
from an
outer surface of the orienting cam/jaw 220 and may mate with the splined
portion 219s
in sliding mode, orienting mode, and rotary mode, thereby rotationally
coupling the
cam/jaw 220 and the jaw housing 219. The splines 220s may also engage the
collet
portion 233c in sliding mode and orienting mode, thereby longitudinally
pushing and
disengaging the rotary jaw 217 from the output jaw 218.
Figure 5C is an isometric view illustrating the asymmetric jaw face 220j of
the
orienting cam/jaw 220. The jaw face 220j may be a crown, spiral, or square and
formed
in an upper longitudinal end of the cam/jaw 220. The jaw face 220j may mesh
with a
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mating jaw face 2181j formed in a lower longitudinal end of the output jaw 218
in sliding
mode, thereby rotationally coupling the orienting shaft 224 and the jaw
housing 219.
The orienting jaw face 220j may be asymmetric and may include two or more
teeth,
each tooth having a unique shape relative to the other teeth. The output jaw
face 218lj
may be correspondingly asymmetric so that the two jaw faces 2181j, 220j may
only
engage or mesh in a single rotational alignment.
Returning to Figures 2A-2F, the cam profile 220c may be a J-slot formed in
an outer surface of the cam/jaw 220. A guide body 221, such as a ring, may be
longitudinally and rotationally coupled to the jaw housing 219 and/or the
orienting
housing 225. The splines 220s may engage the guide body 221 in the neutral
position.
A guide, such as a pin 221 p, may be fastened to a guide body 221 and extend
into the
J-slot 220c, thereby operably coupling the cam/jaw 220 to the orienting
housing 225.
The cam/jaw 220 may be longitudinally coupled to the orienting piston 222,
such as by a ball-groove connection 242b and a thrust bearing 242t. The ball-
groove
connection 242b may be radially disposed between the orienting piston 222 and
the
cam/jaw 220 and the thrust bearing 242t may be longitudinally disposed between
a
lower longitudinal end of the cam/jaw 220 and an upper longitudinal end of an
upper
piston portion 222up of the orienting piston 222 to allow the cam/jaw 220 to
rotate
relative to the orienting piston 222. The grooves of the ball-groove
connection 242b
may be oversized, the lower longitudinal end of the cam/jaw 200 may be
conical, and a
thrust disc 244 may be longitudinally disposed between the thrust bearing 242t
and the
lower longitudinal end of the cam/jaw 220 and have a mating conical upper
longitudinal
end to form an articulating connection between the cam/jaw 220 and the
orienting
piston 222. The articulating connection may facilitate engagement of the
asymmetric
jaw faces 2181j, 220j.
The cam/jaw 220 may also be disposed around the orienting piston 222. The
orienting piston 222 may include an upper sleeve portion 222us, an upper
piston
portion 222up, a lower piston portion 2221p, and a lower sleeve portion 2221s.
The
orienting piston 222 may be disposed around the orienting shaft 224 such that
an
annulus may be formed therebetween. The annulus may serve as a lubricant 2500
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CA 02780351 2012-06-14
conduit. An upper spring stop may be longitudinally coupled to the orienting
housing
225, such as with engaging shoulders. A lower spring stop may be
longitudinally
coupled to the orienting piston 222, such as with a fastener (i.e., a snap
ring). The
orienting spring 223, such as a coil spring or other biasing member, may be
radially
disposed between the orienting housing 225 and the orienting piston 222 and
longitudinally abut the two stops, thereby biasing the orienting piston
longitudinally
away from the output jaw 218.
The orienting spring 223 may have a substantially lesser stiffness (i.e.,
substantially lesser length and/or thickness) than a stiffness of the rotary
cam spring
211 such that a substantially lesser pressure, exerted on the orienting piston
222, is
required to compress the rotary cam spring 211 than the pressure required on
the
rotary piston 212 to compress the rotary cam spring 211. This substantial
stiffness
differential may allow the orienter 200 to be shifted between sliding and
rotary modes
without entering the neutral position. As discussed more below, skipping the
neutral
position may be achieved by rotating or indexing the rotary cam 210 without
indexing
the orienting cam profile 220c.
Each of the piston portions 222up, 2221p may be an enlarged portion having
an outer surface engaging an inner surface of the orienting housing 225. An
inner
surface of the orienting housing 225 may taper 225t (longitudinally downward)
from a
reduced diameter to an enlarged diameter so that an outer diameter of the
upper piston
portion 222up is less than an outer diameter of the lower piston portion
2221p. One or
more seals may be disposed in the outer surface of each piston portion 222up,
2221p
and may isolate an upper longitudinal end from a lower longitudinal end of
each piston
portion 222up, 2221p. An upper longitudinal end of the upper piston 222up and
a lower
longitudinal end of the lower piston 2221p may be in fluid communication with
the
lubricant reservoir 205r and a lower longitudinal end of the upper piston
222up and an
upper longitudinal end of the lower piston 2221p may be in fluid communication
with the
returns 250r via a radial port 225p formed through a wall of the orienting
housing 225.
When an increased lubricant 2500 pressure (relative to the returns 250r or
annulus pressure) is exerted on the piston portions 222up, 2221p, the upper
piston
CA 02780351 2012-06-14
222up may partially counteract the lower piston 2221p, since the upper piston
may have
a reduced piston area relative to the lower piston area. This partial
counteraction may
reduce a net effective piston area of the orienting piston 222 relative to the
rotary piston
212. The radial port 225p may or may not have a filter fastened therein, such
as with a
threaded connection, for preventing entry of cuttings from the returns 250r.
The lower bearing subassembly LB may include a lower portion of the
orienting shaft 224, a lower portion of the orienting housing 225, one or more
bearings
226, 2271, 227u, 228, a lower bearing housing 229, an output shaft 230, and a
cap 231.
A lower longitudinal end of the orienting shaft 224 may be longitudinally and
rotationally
coupled to an upper longitudinal end of the output shaft 230, such as by a
threaded
connection. The bearing 226 may be a radial bearing for radially supporting
and
centralizing rotation of the orienting shaft 224 from the orienting housing
225. The
radial bearing 226 may be a journal bearing including an inner journal
longitudinally and
rotationally coupled to the orienting shaft 224, such as by a press fit and an
outer
journal longitudinally and rotationally coupled to the orienting housing, such
as by one
or more seals to mimic a press fit or a press fit. The radial bearing 226 may
be
longitudinally disposed between a shoulder 224s extending from the outer
surface of
the orienting shaft 224 and a fastener. Each of the bearings 227u, 2271 may be
thrust
bearings, such as rolling element bearings, for supporting longitudinal loads
during
drilling, such as weight exerted on the drill bit 105 by the coiled tubing
string 130. The
upper thrust bearing 227u may be longitudinally disposed between a lower
longitudinal
end of the orienting shaft 224 and an upper longitudinal end of the lower
bearing
housing 229 and radially disposed between the orienting housing 225 and the
output
shaft 230.
A lower longitudinal end of the orienting housing 225 may be longitudinally
and rotationally coupled to an upper longitudinal end of the lower bearing
housing 229,
such as by a threaded connection. The lower thrust bearing 227u may be
longitudinally
disposed between a shoulder 229s of the lower bearing housing 229 and a
shoulder
230s of the output shaft 230 and radially disposed between the lower bearing
housing
229 and the output shaft 230. The bearing 228 may be a radial bearing, such as
a
journal bearing, for radially supporting and centralizing rotation of the
output shaft 230
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from the lower bearing housing 230 and carrying radial load generated by
bending of
the orienter 200 during drilling. The radial bearing 228 may include an inner
journal
longitudinally and rotationally coupled to the output shaft 230 and an outer
journal
longitudinally and rotationally coupled to the lower bearing housing 229.
The cap 231 may be longitudinally and rotationally coupled to the lower
bearing housing 229, such as by a threaded connection. The cap 231 may include
one
or more seals engaging an outer surface of the output shaft 230 and isolating
lubricant
2500 in the orienter shaft-housing annulus from the returns 250r. A lower
longitudinal
end of the output shaft may 230 may be longitudinally and rotationally coupled
to the
MWD module 115, such as by a threaded connection.
The housings 203, 206, 208, 213, 219, 225, 229 of the orienter 200 may each
be tubular and have a central longitudinal bore formed therethrough. The
shafts 205,
214, 224, 230 of the orienter 200 may each be tubular members and, with the
exception
of the crossover shaft 205, each have a central longitudinal bore formed
therethrough.
The housings and shafts may each be made from a metal or alloy, such as steel,
stainless steel, or specialty alloy, depending on the specific wellbore
conditions. The
jaws 217, 218, 220, and cam 210 may be made from a metal or alloy, such as
steel or
stainless steel and may be hardened to resist wear or made from a wear
resistant metal
or alloy, such as tool steel. The seals may be made from a polymer, such as an
elastomer, and are denoted by black filling in Figures 2A-2F. The use of
directional
terms, such as upper and lower, may be arbitrary as the orienter 200 may be
disposed
in deviated or horizontal wellbores.
Figures 3A-3C are isometric views illustrating the clutch subassembly C of
the orienter 200 in a neutral position. The neutral position may be used to
shift the
orienter between the rotary and sliding modes and change the tool face
setting. To
shift the orienter to the neutral position, injection of the drilling fluid
250f may be ceased
or substantially ceased from a first predetermined flow rate, such as a flow
rate
sufficient to sustain drilling. The pressure differential between the drilling
fluid 250f (and
lubricant 250o via balance piston 204) and the returns 250r may be
correspondingly
equalized or substantially equalized. Alternatively, the first predetermined
flow rate
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may instead be a flow rate sufficient to operate the bit motor 110, the BHA
motor 201,
and/or the MWD module 115.
Fluid pressure across the pistons 212, 222 may subsequently equalize,
thereby substantially eliminating or eliminating any actuation force exerted
on the
pistons 212, 222 by the lubricant 250o. The rotary spring 211 may then
decompress,
thereby moving the rotary piston 212 longitudinally away from the output jaw
218. The
rotary piston 212 may carry the rotary cam 210 longitudinally coupled thereto.
As the
rotary cam 210 longitudinally moves within the upper bearing housing 208, the
J-slot
may ride along the pin 234, thereby rotating the rotary cam 10 half-way to the
next
mode, i.e. rotary or sliding, dependant on which mode the orienter 200 was
previously
in.
The orienting spring 223 may also decompress, thereby moving the orienting
piston 222 longitudinally away from the output jaw 218. The orienting piston
222 may
carry the orienting cam/jaw 220 longitudinally coupled thereto. As the
orienting
cam/jaw 220 moves longitudinally, the splines 220s may disengage from the
splined
portion 219s, thereby rotationally decoupling the cam/jaw 220 from the clutch
housing
219 and deleting the current tool face setting. As the cam/jaw 220
longitudinally moves
within the upper bearing housing 208, the J-slot may ride along the pin 221p,
thereby
rotating the cam/jaw 220 half-way to the next tool face setting.
The rotary actuator 216 may be longitudinally biased into engagement with
the rotary jaw 217 by the rotary jaw spring 232. The rotary actuator 216 may
push the
rotary jaw 217 into engagement with the output jaw 218. Engagement of the
rotary jaw
217 with the output jaw 218 may rotationally couple the orienting shaft 224
with the
rotary shaft 214, thereby also rotationally coupling the BHA rotor 201r and
the output
shaft 230.
Alternatively and as discussed above, the orienter 200 may be switched
between rotary and sliding modes without switching to, or bypassing, the
neutral
position, thereby maintaining the tool face TF setting or orientation of the
orienter 200.
To shift the orienter 200 into the bypass position, the injection rate may be
substantially
reduced from the drilling flow rate and/or substantially reducing (or lifting
the drill bit 105
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CA 02780351 2012-06-14
from bottomhole) weight exerted on the drill bit 105. The flow rate may be
reduced to a
second predetermined or bypass flow rate substantially less than the drilling
flow rate
and substantially greater than zero, such as one-third, one-half, or two-
thirds of the
drilling flow rate. Due to the reduced pressure differential, the rotary cam
spring 211
may decompress, thereby actuating the rotary cam 210, but the fluid force on
the
orienting piston 222 may remain sufficient to maintain compression of the
orienting
spring 223, thereby maintaining engagement of the orienting cam/clutch 220
with the
jaw housing 219.
The bypass position may be different when shifting from the sliding mode to
the rotary mode (not shown as separate Figure; however, see combination of
Figures
3A and 4D) than when shifting from the rotary mode to the sliding mode (not
shown as
separate Figure; however, see combination of Figures 3A and 5A). When shifting
from
sliding to rotary mode, the orienting clutch face 220j may remain engaged to
the lower
output jaw face 2181j. When shifting from rotary to sliding mode, the jaw
faces 2181j,
220j may likely be misaligned so that the asymmetric teeth contact, thereby
generating
a frictional torque. Since there may be little or no weight exerted on the
drill bit 105
and/or substantially reduced flow through the bit motor 110, the reactive
torque exerted
by the bit motor 110 may be insufficient to overcome the frictional torque and
counter
rotate the output shaft 230.
Alternatively, the orienter 200 may be shifted into the bypass position by
ceasing or substantially ceasing injection of the drilling fluid for an
interval of time
sufficient to allow decompression of the rotary cam spring 211 but
insufficient to allow
decompression or substantial decompression of the orienting spring 223.
Figures 4A-4D are isometric side-by-side views comparing a portion of the
clutch subassembly C in rotary mode (Figures 4A and 4C) and sliding mode
(Figures
4B and 4D). To shift the orienter 200 from either the bypass position or the
neutral
position to the rotary or sliding mode, an injection rate of the drilling
fluid 250f is
increased to the drilling flow rate and/or weight is exerted on the drill bit
105. The
pressure differential between the drilling fluid 250f (and lubricant 250o via
balance
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CA 02780351 2012-06-14
piston 204) and the returns 250r is correspondingly increased due to pressure
loss
through the bit motor 110 and the drill bit 105.
Due to the differential pressure, an actuation force may be exerted on the
rotary piston 212 by the lubricant 250o, thereby moving the rotary piston 212
longitudinally toward the rotary actuator 216 and compressing the rotary cam
spring
211. The rotary piston 212 may carry the rotary cam 210 longitudinally coupled
thereto.
As the rotary cam 210 longitudinally moves within the upper bearing housing
208, the J-
slot may continue along the pin 234, thereby completing rotation of the rotary
cam 210
to the next mode, i.e. rotary or sliding, dependant on which mode the orienter
200 was
previously in.
Referring to Figures 4A and 4C, if the previous mode was sliding mode, the
orienter 200 may switch to rotary mode. The keys 210k may align with the
keyways
formed in the upper bearing housing 208, thereby allowing longitudinal passage
of the
rotary cam 210 and the upper sleeve portion 212us (longitudinally coupled
thereto)
through the lower longitudinal end of the upper bearing housing 208 and into
the upper
longitudinal end of the rotary housing 213. Longitudinal movement may continue
until
the lower sleeve 2121s engages the rotary actuator 216. The rotary actuator
216 may
push the rotary jaw 217 into engagement with the output jaw 218. Engagement of
the
rotary jaw 217 with the output jaw 218 may rotationally couple the orienting
shaft 224
with the rotary shaft 214, thereby also rotationally coupling the BHA rotor
201 r and the
output shaft 230. The rotary jaw 217 may also push against the sleeve portion
233s of
the jaw shifter 233.
The cam/jaw 220 may be disengaged from the output jaw 218 by the jaw
shifter 233. Specifically, the collet portion 233c may engage the splines
220s, thereby
pushing the jaw face 220j from the lower jaw face 2181j. As discussed above,
since the
net effective piston area of the orienting piston 222 may be less than the
piston area of
the rotary piston 212, the rotary piston 212 may exert a greater downward
force on the
jaw shifter 233 than the upward force exerted by the orienting piston 222. The
cam/jaw
220 may remain engaged with the jaw housing 219 in rotary mode so that the
tool face
setting is retained. Specifically, the splined portion 219s may have
sufficient length so
CA 02780351 2012-06-14
that the collet portion 233c may hold the jaw face 220j away from the lower
jaw face
2181j while the splines 220s remain engaged to the splined portion 219s.
Referring to Figures 4B and 4D, if the previous mode was rotary mode, the
orienter 200 may switch to the sliding mode. The keys 210k may align with and
engage
the keys formed in the upper bearing housing 208, thereby restraining
longitudinal
movement of the rotary cam 210. The rotary piston 212, longitudinally coupled
to the
rotary cam 210, may be consequently prevented from moving longitudinally
toward and
engaging the rotary actuator 216. The longitudinal restraint of the rotary
piston 212
may allow the orienting piston 222 to disengage the rotary jaw 217 from the
output jaw
218 and engage the orienting cam/jaw 220 with the output jaw 218 and the jaw
housing
219, thereby rotationally coupling the output shaft 230 to the jaw housing
219.
Specifically, the splines 220s may push the collet portion 233c and the sleeve
portion
233s may push the thrust bearing 238 and the thrust bearing 238 may push the
rotary
jaw 217 and the rotary jaw 217 may push the thrust bearing 237 and the thrust
bearing
237 may push the rotary actuator 216 and the rotary actuator 216 may compress
the
rotary jaw spring 232.
Due to rotation of the output jaw 218 in rotary mode, the output jaw 218 and
the orienting cam/jaw 220 may likely be misaligned so that the orienter 200
shifts into
orienting mode (see Figures 5A and 5B) to rotationally align the asymmetric
jaw faces
2181j, 220j for engagement, thereby restoring the previous tool face setting
(assuming
the bypass position is used to shift the orienter from rotary to sliding mode
and not the
neutral position). Once the orientation cam/jaw 220 and the output jaw 218 are
engaged, the orienter 200 is rotationally locked in the sliding mode at the
previously set
tool face orientation.
Figures 5A and 5B are isometric views illustrating a portion of the clutch
subassembly C in the orienting mode. The orienter 200 may shift into the
orienting
mode either to restore a previous tool face setting when shifting from rotary
to sliding
mode using the bypass position or to enter a new tool face setting when
shifting from
the neutral position to the sliding mode.
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CA 02780351 2012-06-14
Starting from the neutral position and assuming the last mode was the rotary
mode so that the next mode is the sliding mode, the injection rate of the
drilling fluid
250f may be increased to the drilling flow rate and the pressure differential
between the
drilling fluid 250f (and lubricant 250o via balance piston 204) and the
returns 250r is
correspondingly increased due to pressure loss through the bit motor 110 and
the drill
bit 105. Due to the differential pressure, an actuation force may be exerted
on the
orienting piston 222 by the lubricant 250o, thereby moving the orienting
piston 222
longitudinally toward the output jaw 218 and compressing the orienting spring
223. The
orienting piston 222 may carry the orienting cam/jaw 220 longitudinally
coupled thereto.
As the cam/jaw 220 longitudinally moves within the upper bearing housing
208, the J-slot may continue along the pin 221p, thereby completing rotation
of the
cam/jaw 220 to the next tool face setting. Longitudinal movement may continue
until
the splines 220s engage the spline portion 219s, thereby rotationally coupling
the
cam/jaw 220 and the jaw housing 219 at the new tool face setting. Longitudinal
movement may continue until the splines 220s engage the jaw shifter 233,
thereby
disengaging the rotary jaw 217 from the output jaw 218. Longitudinal movement
may
continue until contact of the misaligned jaw faces 2181j, 220j. Once contact
is made,
reactive (i.e., counterclockwise) rotation of the jaw face 218Ij by the bit
motor 110
relative to the jaw face 220j may be required until the jaw faces 2181j, 220j
align and
engage. Once the orientation cam/jaw 220 and the output jaw 218 are engaged,
the
orienter is rotationally locked in the sliding mode at the new tool face
orientation.
If the last mode was sliding mode so the next mode is rotary mode, the
orienter 200 may not enter the orienting mode. The new tool face setting may
be
retained by engagement of the splines 220s with the splined portion 219s;
however, the
orientation cam/jaw 220 may be unable to disengage the rotary jaw 217 from the
output
jaw 218 due to engagement of the rotary piston 212 with the rotary actuator
216 so that
the new tool face setting may not be entered until the orienter is shifted
from the rotary
mode to the sliding mode.
Figure 6A is a table illustrating surface indicators for determining which
mode/position the orienter 200 is in. Figure 6B is a flow chart illustrating a
method for
22
CA 02780351 2012-06-14
determining which operational mode the orienter 200 is currently in. The
indicators may
include injection rate or flow rate of drilling fluid 250f injected into the
coiled tubing
string 130 by the rig mud pump, whether the tool face TF (or bent housing 110)
is
rotating or fixed which may be determined from signals sent by the MWD module,
and/or rate of penetration (ROP). A zero injection rate of drilling fluid may
indicate that
the orienter 200 is in the neutral position due to no differential pressure
across the
rotary 212 and orienting 222 pistons. A full drilling flow rate may indicate
that the
orienter is in one of the three operating modes: rotary, orienting, or sliding
as a
sufficient differential pressure may be exerted on the rotary 212 and
orienting 222
pistons to compress the respective springs 211, 223 and both the BHA motor 201
and
bit motor 110 may be operating.
A rotationally fixed tool face TF (or bent housing 110) may indicate that the
orienter 200 is either in the neutral position or sliding mode because the BHA
motor 201
is not operating or the orienting cam/jaw 220 is engaged with the jaw housing
219 and
the output jaw 218. A rotating tool face TF (or bent housing 110) may indicate
that the
orienter 200 is in rotary mode or orienting mode because the BHA motor 201 may
be
rotating the output shaft 230 or the bit motor 110 is counter-rotating the
output shaft
230. The rotary mode and the orienting mode may further be distinguished by
calculating a rate in change of tool face TF orientation (i.e., right-hand
rotational velocity
positive and left-hand rotational velocity negative). A low ROP may indicate
orienting
mode because the bit motor 110 is counter-rotating the output shaft 230
instead of, or
in addition to, the drill bit 105.
Figure 6C is a flowchart illustrating a method for switching the orienter 200
from the sliding mode to the rotary mode using the bypass position. Starting
from the
orienter 200 in sliding mode with drilling fluid 250f being injected through
the BHA 100
at the drilling flow rate and with weight exerted on the drill bit, a first
attempt may be
made to shift the orienter 200 by lifting the drill bit 105 from the bottom of
the wellbore
and then exerting weight back on the drill bit 105. Injection of the drilling
fluid 250f may
be maintained at the drilling rate for the first attempt. The pressure
differential across
the rotary piston 212 may be sufficiently reduced to index the rotary cam 210
and
disengage the orienting cam/jaw 220 from the output jaw 218 and as indicated
by a
23
CA 02780351 2012-06-14
rotating tool face TF (or bent housing 110). If so, then the ROP may be
monitored to
determine if the rotary jaw 217 has engaged the output jaw 218 as indicated by
a high
ROP. If so, then the orienter 200 has successfully shifted from sliding mode
to the
bypass position to the rotary mode.
If the tool face TF is rotating but the ROP is low, then the differential
pressure
may be insufficient to engage the rotary jaw 217 with the output jaw 218. A
remedial
step of increasing the weight exerted on the drill bit 105 and/or increasing
the injection
rate of the drilling fluid 250f may be attempted to increase the differential
pressure
exerted on the rotary piston 212. If the remedial step fails, the rotary jaw
217 may be
damaged, thereby necessitating pulling of the orienter 200 from the wellbore
or hole
(POOH) for servicing. As an alternative, use of the orienter 200 may continue
but be
restricted to sliding mode.
If the tool face TF remains rotationally fixed after the first attempt, the
decrease in differential pressure may be insufficient to index the rotary cam
210 or
friction may be holding the orienting cam/jaw 220 and the output jaw 218
together. A
remedial step of increasing the weight exerted on the drill bit 105 and/or
increasing the
injection rate of the drilling fluid 250f may be attempted to increase the
differential
pressure exerted on the rotary piston 212, thereby increasing the force
exerted on the
gear shifter 233 to attempt to dislodge the orienting cam/jaw 220 from the
output jaw
218. If the remedial step fails, then it may be assumed that the rotary cam
did not
engage. The drill bit 105 may be lifted from the bottomhole and the flow rate
reduced to
the bypass flow rate, discussed above, to further reduce the differential
pressure acting
on the rotary piston 212. The flow rate may then be increased back to the
drilling flow
rate and the tool face TF may be checked for rotation. If the tool face TF is
rotating,
then weight may be applied to the drill bit 105 and the ROP may be checked, as
discussed above. If the tool face TF remains fixed, then the remedial step may
be
repeated. If the remedial step fails, then the drill bit 105 may be lifted
from the
bottomhole and the flow rate ceased to positively assure that the rotary cam
210
indexes (although the orienting cam/jaw 220 may also index as well). The tool
face TF
may again be checked for rotation. If the tool face TF remains fixed, then the
orienter
200 may be removed from the wellbore for servicing.
24
CA 02780351 2012-06-14
Figure 6D is a flowchart illustrating a method for switching the orienter 200
from the rotary mode to the sliding mode using the bypass position. Starting
from the
orienter 200 in rotary mode with drilling fluid 250f being injected through
the BHA 100 at
the drilling flow rate and with weight exerted on the drill bit 105, a first
attempt may be
made to shift the orienter 200 by lifting the drill bit 105 from the bottom of
the wellbore.
Injection of the drilling fluid 250f may be maintained at the drilling rate
for the first
attempt. The pressure differential across the rotary piston 212 may be
sufficiently
reduced to disengage the rotary jaw 217 from the output jaw 218 as indicated
by a
rotationally fixed tool face TF (or bent housing 110). As discussed above, the
jaw faces
2181j, 220j may contact but there may be insufficient counter torque to
overcome the
frictional contact torque. If so, then the weight may be reapplied to the
drill bit 105,
thereby increasing the counter torque so that the orienter may shift into
orienting mode
and align the asymmetric jaw faces 2181j, 220j. Engagement of the orienting
cam/jaw
220 with the output jaw 218 may then be indicated by a rotationally fixed tool
face TF.
If so, the ROP may be monitored to determine that the BHA 100 is functioning
properly
as indicated by a high ROP. If so, then the orienter 200 has successfully
shifted from
rotary mode, to the bypass position, to the orienting mode, and then to the
sliding
mode.
If the tool face TF is fixed but the ROP is low, then there may be a
malfunction elsewhere in the BHA 100, such as a motor failure. If the tool
face TF is
rotating after weight is exerted on the bit 105, then the differential
pressure may be
insufficient to engage the orienting cam/jaw 220 with the output jaw 218 as
indicated by
a low ROP. A remedial step of increasing the weight exerted on the drill bit
105 and/or
increasing the injection rate of the drilling fluid 250f may be attempted to
increase the
differential pressure exerted on the orienting piston 222. If the remedial
step fails, the
orienting cam/jaw 220 may be damaged, thereby necessitating pulling of the
orienter
200 from the wellbore or hole (POOH) for servicing. As an alternative, use of
the
orienter 200 may continue but be restricted to rotary mode.
If the tool face TF is rotating after weight is exerted on the bit 105, then
the
rotary cam 210 may not have indexed and the rotary jaw 217 may have reengaged
with
the output jaw 218 as indicated by a high ROP. If so, the decrease in
differential
CA 02780351 2012-06-14
pressure may be insufficient to disengage the rotary piston 212 from the
rotary jaw 217
or friction may be holding the rotary jaw 217 and the output jaw 218 together.
The drill
bit 105 may be lifted from the bottomhole and the flow rate reduced to the
bypass flow
rate, discussed above, to further reduce the differential pressure acting on
the rotary
piston 212. The tool face TF may then be checked for rotation. If the tool
face TF is
still rotating, the injection rate of the drilling fluid 250f may be increased
to the drilling
flow rate and the tool face TF again checked for rotation. If the tool face TF
is still
rotating, then weight may be reapplied to the drill bit 105 and the ROP
checked. If the
ROP is high, then the injection rate may be increased and/or weight on the bit
may be
increased. If the tool face TF is still rotating, then the drill bit 105 may
be lifted from the
bottomhole and injection of the drilling fluid may be ceased. This may result
in a
change of the tool face TF orientation. Injection of the drilling fluid 250f
may then be
resumed at the drilling fluid rate and the tool face TF again checked. If the
tool face TF
is still rotating, then weight may be applied to the bit 105 and the ROP
checked. If the
ROP is still high, then the injection rate may be increased and/or weight on
the bit 105
may be increased. If the tool face TF is still rotating, then the orienter 200
may be
removed from the wellbore for servicing.
If, after the flow rate is reduced to the bypass flow rate, the tool face TF
is
fixed, then the injection rate may be increased to the drilling flow rate and
weight may
be applied to the drill bit 105 and the tool face TF may again be checked, as
discussed
above. If, after the flow rate is increased to the drilling flow rate, the
tool face is fixed,
then weight may be applied to the drill bit 105 and the tool face TF may again
be
checked, as discussed above. If, after weight is applied to the drill bit 105,
the tool face
TF is fixed, then the ROP may be checked, as discussed above.
Figure 6E is a flowchart illustrating a method for changing the tool face TF
setting or orientation. Starting from the orienter 200 in sliding mode with
drilling fluid
being injected through the BHA 100 at the drilling flow rate and with weight
exerted on
the drill bit 105, the orienter 200 may be switched to rotary mode using the
bypass
position (see Figure 6C, above). Once in rotary mode, the injection of
drilling fluid 250f
may be ceased and then resumed after a predetermined increment of time
sufficient to
allow expansion of the orienting spring 223. If the new desired orientation
requires
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CA 02780351 2012-06-14
more than one increment, the drilling fluid 250f flow may again be cycled as
many times
as necessary to achieve the new desired orientation. If the number of cycles
performed
is odd, then the orienter 200 may be back in sliding mode since the rotary cam
210 may
have indexed as well as the orienting cam/jaw 220. If so, then weight may be
applied
to the bit 105 and the tool face TF checked for rotation. If the tool face TF
is fixed, then
the orientation of the tool face TF may be checked using the MWD module 115.
If the
tool face TF orientation is correct, then the ROP may be checked to ensure the
BHA
100 is properly functioning. If the ROP is high, then the tool face TF setting
has been
successfully changed and the orienter 200 has been successfully shifted back
into
sliding mode at the new desired orientation.
If the number of cycles performed is even, then the orienter 200 may be in
rotary mode. Weight may be applied to the drill bit 105 and the tool face TF
checked
for rotation. If the tool face TF is rotating, then the ROP may be checked. A
high ROP
may verify that the orienter 200 is in rotary mode. The orienter 200 may then
be shifted
back into sliding mode using the bypass position so that the orientation is
not
unintentionally changed. Once the orienter 200 is shifted back into sliding
mode, then
the orientation of the tool face may be checked, as discussed above.
If the orientation is not correct in either of the above cases, then the
orienting
cam/jaw 220 may not have indexed during one or more of the flow cycles. The
orienter
200 may be shifted into rotary mode, the bit 105 lifted from the bottomhole,
and the flow
cycling repeated to correct the deficient orientation. If the tool face TF is
fixed after an
even number of cycles or rotating after an odd number of cycles, then the
rotary piston
212 may not have retracted sufficiently to index the rotary cam 210 and the
orienter 200
may be in rotary mode when the orienter 200 should be in sliding mode and vice
versa.
However, the orienting cam/jaw 220 may still have indexed for each cycle so
the
orientation may still be correct. If the orienter 200 is in rotary mode, then
the orienter
200 may be shifted into sliding mode using the bypass position and the
orientation of
the tool face TF checked, as discussed above. If the orienter 200 is in
sliding mode,
then the orientation of the tool face TF may be checked, as discussed above.
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CA 02780351 2012-06-14
The rest of the flow chart illustrates remedies for sticking of the orienter
200
between the sliding and rotary mode, similar to the remedies discussed above
for
Figures 6C and 6D.
While the foregoing is directed to embodiments of the present invention,
other and further embodiments of the invention may be devised without
departing from
the basic scope thereof, and the scope thereof is determined by the claims
that follow.
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