Note: Descriptions are shown in the official language in which they were submitted.
Invention Disclosure
TITLE OF INVENTION
Controlled Full Flow Pressure Pulser for Measurement While Drilling
(MWD) Device
FIELD OF DISCLOSURE
The current invention includes an apparatus and a method for creating a pulse
within the
drilling fluid, generally known as drilling mud, that is generated by
selectively initiating
flow driven bidirectional pulses within a bore pipe. Features of the device
include operating
a flow throttling device [FTD] that operates without a centrally located valve
guide within a
newly designed annular flow channel, such that the annular flow channel
provides an
increased area for the flow of the drilling fluid and also allows for the
addition of an
intelligent computerized control system using a combination of hardware and
software tools
with downlink capability. The downlink tools may be located above or below a
positive
displacement motor. The intelligent control system provides and maintains
several
parameters that effect drilling or other downhole activity efficiency (i.e.
Weight on Bit, Rate
of Penetration, Pulse Amplitude, Axial Vibration, Borehole Pressure, etc.) by
utilizing a
feedback control loop such that the pressure differentials within the collar
and associated
annulus of the FTD inside a bore pipe provide information for properly
controlled,
reproducible pressure pulses that exhibit little or no associated signal noise
. The pulse
received "up hole" from the tool down hole includes a series of dynamic
pressure changes
that provide pressure signals which can be used to interpret inclination,
azimuth, gamma
ray counts per second, etc. by oilfield personnel. These dynamic pressure
changes and
resulting signals are utilized to further increase yield in oilfield
operations.
BACKGROUND
Current pulser technology utilizes pulsers that are sensitive to different
fluid pump down
hole pressures, and flow rates, and require field adjustments to pulse
properly so that
meaningful signals from these pulses can be received and interpreted uphole.
CA 2896287 2019-04-29
An important advantage of the present disclosure and the associated
embodiments is that it
decreases sensitivity to fluid flow rate or pressure within easily achievable
limits, does not
require field adjustment, and is capable of creating recognizable, repeatable,
reproducible,
yet controlled, clean [i.e. noise free] fluid pulse signals using minimum
power due to a
unique flow throttling device [FTD] with a pulser that requires no guide,
guide pole or other
guidance system to operate the main valve, thus reducing wear, clogging and
capital
investment of unnecessary equipment as well as increasing longevity and
dependability in
the down hole portion of the MWD tool. This MWD tool still utilizes battery,
magneto-
electric and/or turbine generated energy. The mostly unobstructed main flow in
the main
flow area enters with full flow into the cone without altering the main flow
pattern The
increased flow rate and change in pressure produces a very efficient pilot
valve response and
associated energy pulses. Specifically, as the pilot valve closes faster (than
in any known
previous designs) this produces large pressure spike similar to a "water
hammer" effect
much like that is heard when shutting off a water faucet extremely quickly.
The faster flow
and corresponding larger pressure differential also moves the pilot valve into
an open and
closed position more rapidly. The faster the closure, the more pronounced the
water
hammer effect and the larger the pulse and associated measured spike
associated with the
pulse. These high energy pulses are also attributed to the position and
integrity of the pilot
channel seals (240) which ensure rapid and complete closure while maintaining
complete
stoppage of flow through the channel. The controllability of the pulser is
also significantly
enhanced in that the shape of the pressure wave generated by the energy pulse
can be more
precisely predetermined. The pulse rise and fall time is sharp and swift ¨
much more so
than with conventional devices utilizing guide pole designs. These more easily
controlled
and better defined energy pulses are easily distinguished from the background
noise
associated with MWD tools. Distinguishing from the "background" noise leading
to ease of
decoding signals occurring on an oil or gas rig offers tremendous advantages
over current
tools. By implementing the feedback control by utilizing sensors to detect
pulse responses,
the pulser can be programmed to operate intelligently responding based on
measured sensor
parameters using preprogrammed logic. Being able to control and determine
pulse size,
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timing, and shape without ambiguity provides the user with reproducible,
reliable data that
results in reduced time on the rig for analysis and more reliable and
efficient drilling.
US Patents 7,180,826 and US Application Number 2007/0104030A1 to Kusko, et.
al.,
disclose a fully functional pulser system that requires the use of a pulser
guide pole to guide
and define the movement of the main valve together with a different hydraulic
channel
designs than that of the present application and associated invention.
SUMMARY
The present disclosure involves the placement of a Measurement-While-Drilling
(MWD)
pulser device including a flow throttling device located within a bore pipe in
a wellbore
incorporating drilling fluids for directional and intelligent drilling. In the
design, the pilot
channel location is very different than in any prior application in that the
channel is now
located on the outside annulus. Features of the device include operating a
flow throttling
device [FTD] that operates without a centrally located valve guide within a
newly designed
annular flow channel, such that the annular flow channel provides an increased
area for the
flow of the drilling fluid and also allows for the addition of an intelligent
computerized
control system using a combination of hardware and software tools with
downlink
capability. The downlink tools may be located above or below a positive
displacement
motor. The intelligent control system provides and maintains several
parameters that effect
drilling or other downhole activity efficiency (i.e. Weight on Bit, Rate of
Penetration, Pulse
Amplitude, Axial Vibration, Borehole Pressure, etc.) by utilizing a feedback
control loop
such that the pressure differentials within the collar and associated annulus
of the FTD
inside a bore pipe provide information for properly guided, reproducible
pressure pulses that
exhibit little or no associated signal noise . The pulse received "up hole"
from the tool down
hole includes a series of dynamic pressure changes that provide pressure
signals which can
be used to interpret inclination, azimuth, gamma ray counts per second, etc.
by oilfield
personnel . These dynamic pressure changes and resulting signals are utilized
to further
increase yield in oilfield operations. The present invention also discloses a
novel device for
creating pulses in drilling fluid media flowing through a drill string. Past
devices, currently
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in use, require springs or solenoids to assist in creating pulses and are
primarily located in
the main drilling fluid flow channel. US Patents 7,180,826 and US Application
Number
2007/0104030A1 to Kusko, et. al., disclose a fully functional pulser system
that requires the
use of a pulser guide pole to guide and define the movement of the main valve
together with
a different hydraulic channel designs than that of the present application and
associated
invention. The pilot flow for the present invention without the guide pole
allows for more
efficient repair and maintenance processes and also allows for quickly
replacing the newly
designed apparatus of the present disclosure on the well site as there is at
least a 15-20
percent reduction in capital costs and the costs on the maintenance side are
drastically
reduced. In the previous designs, guide pole failures accounted for 60-70
percent of the
downhole problems associated with the older versions of the MWD. With the
guide pole
elimination, reliability and longer term down hole usage increases
substantially, providing a
more robust tool and much more desirable MWD experience.
Additionally, previous devices also required onsite adjustment of the flow
throttling device
(FTD) pulser according to the flow volume and fluid pressure and require
higher energy
consumption due to resistance of the fluid flow as it flows through an opened
and throttled
position in the drill collar.
The elimination of the centralized guide pole and pilot channel allows, in the
current design,
larger pressure differential to be created between the pilot flow and the main
flow at the
main valve thus increasing the control and calibration and operation of the
pulser. The
ability to precisely control the pulser and thus the pressure pulse signals is
directly related to
cleaner, more distinguishable and more defined signals that can be easier
detected and
decoded up hole.
Additional featured benefits of the present inventive device and associated
methods include
having a pulser tool above and/or below the PDM (positive displacement motor)
allowing
for intelligence gathering and transmitting of real time data by using the
pulser above the
motor and as an efficient drilling tool with data being stored in memory below
the motor
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with monitored borehole pressure, acceleration, as well as downhole WOB
control, among
other drilling parameters. Drilling parameter control is accomplished by using
a set point
and threshold for the given parameter and adjusting based on effects provided
by the shock
wave generated using the FTD. Master control is provided uphole or downhole
with a
feedback loop from the surface of the well or from intelligent programming
incorporated in
the pulsing device in the BHA above and/or below the PDM
The device provided by the current invention allows for the use of a flow
throttling device
that moves from an initial position to an intermediate and final position in
both the upward
and downward direction corresponding to the direction of the fluid flow. The
present
invention still avoids the use of springs, the use of which are described in
the following
patents as presented in U.S. Pat. No's 3,958,217, 4,901,290, and 5,040,155.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an overview of the full flow MWD with feedback control.
Figure 2 is a close up of the pilot flow screen assembly
Figure 3 is a detailed cross section of the main valve actuator assembly
including the seals.
Figure 4 shows the lower portion of the pilot actuator assembly, drive shaft
and motor.
Figure 5 is a pulser feedback control flow diagram.
DETAILED DESCRIPTION OF THE DRAWINGS
With reference now to Figure 1, the pulser assembly [400] device illustrated
produces
pressure pulses in drilling fluid main flow [110] flowing through a tubular
hang-off collar
[120] and includes a pilot flow upper annulus [160]. The flow cone [170] is
secured to the
inner diameter of the hang off collar [120]. Major assemblies of the MWD are
shown as
provided including aligned within the bore hole the pilot flow screen assembly
[135] and
main valve actuator assembly [229] and pilot actuator assembly [335].
In Figure 1, starting from an outside position and moving toward the center of
the main
valve actuator assembly [229] comprising a main valve [190], a main valve
pressure
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chamber [200], a main valve support block [350], main valve seals [
225,226,227,228] and
flow guide seal [240]. The same figure shows the main valve feed channel
[220], the pilot
orifice [250], pilot valve [260], pilot flow shield [270], bellows [280] and
the anti-rotation
block [290], as well as a cylindrical support shoulder [325] and tool face
alignment key
[295] that exists below the pilot flow shield [270] for keeping the pulser
assembly centered
within the bore hole. This figure also shows the passage of the main flow
[110] past the
pilot flow screen [130] through the main flow entrance [150], into the flow
cone [170],
through the main orifice [180] into and around the main valve [190], past the
main valve
pressure chamber [200], past the main valve seals [225,226,227,228] through
the main valve
support block [350], after which it combines with the pilot exit flow [320] to
become the
main exit flow [340]. The pilot flow [100] flows through the pilot flow screen
[130] into the
pilot flow screen chamber [140], through the pilot flow upper annulus [160],
through the
pilot flow lower annulus [210] and into the pilot flow inlet channel [230],
where it then
flows up into the main valve feed channel [220] until it reaches the main
valve pressure
chamber [200] where it flows back down the main valve feed channel [220],
through the
pilot flow exit channel [360], through the pilot orifice [250], past the pilot
valve [260] where
the pilot exit flow [320] flows over the pilot flow shield [270] where it
combines with the
main flow [110] to become the main exit flow [340] as it exits the pilot valve
support block
[330] and flows on either side of the rotary magnetic coupling [300], past the
drive shaft and
the motor [310].
The pilot actuator assembly [335] includes a magnetic pressure cup [370], and
encompasses
the rotary magnetic coupling [300]. The magnetic pressure cup [370] and the
rotary
magnetic coupling [300] may comprise several magnets, or one or more
components of
magnetic or ceramic material exhibiting several magnetic poles within a single
component.
The magnets are located and positioned in such a manner that the rotatry
movement or the
magnetic pressure cup [370] linearly and axially moves the pilot valve [260].
The rotary
magnetic coupling [300] is actuated by the adjacent drive shaft [305].
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Figure 2 provides details of the pulser assembly in the open position; the
pilot flow [100]
and main flow [110] both flow through the pilot flow screen assembly [135] and
pilot flow
screen [130] where a portion of the main flow [110] flows through the pilot
flow screen
[130]. The pilot flow [100] flows through the pilot flow screen chamber [140]
and into the
.. pilot flow upper annulus [160]. Pilot flow [100] and main flow [110] within
the pilot flow
screen assembly [135] flows through the main flow entrance [150] and through
the flow
cone [170] and into the main orifice [180] to allow for flow within the main
valve feed
channel [220].
Figure 3 describes the main valve actuator assembly [229] and illustrates the
flow of the
pilot flow [100] and main flow [110] areas with the main valve [190] in open
position. The
main flow [110] passes through openings in the main valve support block [350]
while the
pilot flow [100] flows through the pilot flow lower annulus [210], into the
pilot flow inlet
channel [230] and into the main valve feed channel [220] which puts pressure
on the main
valve pressure chamber [200] ] when the pilot valve [260] is in closed
position. The pilot
flow [100] then flows out through the pilot flow exit channel [360], through
the pilot orifice
[250] and over the pilot valve [260]. Also shown are the seals [225, 226, 227,
228 &240] of
the main valve actuator assembly.
When pilot valve [260] closes, pressure increases through the main valve feed
channel [220]
into the main valve pressure chamber [200]. The upper outer seal [227], upper
inner seal
[225], lower inner seal [226], lower outer seal [228] and flow guide seal
[240] keep the pilot
flow [100] pressure constrained and equal to the pressure that exists in main
flow entrance
[150] area.
Upper outer seal [227] and lower outer seal [228] exclude large particulates
from entering
into the space where the upper inner seal [225] and lower inner seal [226]
reside. The upper
outer seal [227] and lower outer seal [228] do not support a pressure load and
allow a small
amount of pilot flow [100] to bypass while excluding particulates from
entering the area
.. around the upper inner seal [225] and lower inner seal [226]. This
eliminates pressure
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locking between the inner seals [225, 226] and the outer seals [227, 228]. By
excluding the
particulates from entering into the space where the inner seals reside [225,
226] the seals are
protected and the clearances of the inner seals [225, 226] can be reduced to
support high
pressure loads. Very small particulates can bypass the outer seals [227, 228],
but the
particulates must be very small in relative to the clearances of the inner
seals [225, 226] to
penetrate the space between the outer seals [227, 228] and inner seals [225,
226].
Referring to Figure 4, an embodiment of the rotary magnetic coupling [300] and
motor [310]
is shown. The Main exit flow [340] flows parallel along each side of the
rotary magnetic
coupling [300] which is contained within the magnetic pressure cup [370], past
the drive
shaft and parallel along each side of the motor [310] down toward the
cylindrical support
shoulder [325] that includes a tool face alignment key [295] below the pilot
flow shield
[270]. The magnetic pressure cup [370] is comprised of a non-magnetic
material, and is
encompassed by the outer magnets [302]. The outer magnets [302] may comprise
several
magnets, or one or more components of magnetic or ceramic material exhibiting
several
magnetic poles within a single component. The outer magnets [302] are housed
in an outer
magnet housing [303] that is attached to the drive shaft. Within the magnetic
pressure cup
[370] are housed the inner magnets [301] which are permanently connected to
the pilot
valve [260]. .
The outer magnets [302] and the inner magnets [301] are placed so that the
magnetic polar
regions interact, attracting and repelling as the outer magnets [302] are
moved about the
inner magnets [301] The relational combination of magnetic poles of the moving
outer
magnets [302] and inner magnets [301], causes the inner magnets [301] to move
the pilot
.. valve [260] linearly and interactively without rotating. The use of outer
magnets [302] and
inner magnets [301] to provide movement from rotational motion to linear
motion also
allows the motor [310] to be located in an air atmospheric environment in lieu
of a
lubricating fluid environment. This also allows for a decrease in the cost of
the motor [310],
decreased energy consumption and subsequently decreased cost of the actual MWD
device.
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It also alleviates the possibility of flooding the sensor area of the tool
with the drilling fluid
like in the use of a moving mechanical seal.
The information flow on the Pulser Control Flow Diagram in Fig. 5 details the
controllable
pulser operation sequence. The drilling fluid pump, known as the mud pump
[500] is
creating the flow with a certain base line pressure. That fluid pressure is
contained in the
entirety of the interior of the drill string [510], known as the bore
pressure. The bore pipe
pressure sensor [420] is sensing this pressure increase when the pumps turn
on, and send
that information to the Digital Signal Processor (DSP) [540] which interprets
it. The DSP
[540] also receives information from the annulus pressure sensor [470] which
senses the
drilling fluid (mud) pressure as it returns to the pump [500] in the annular
(outside) of the
drill pipe [520]. Based on the pre-programmed logic [530] in the software of
the DSP [540],
and on the input of the two pressure sensors [420, 470] the DSP [540]
determines the correct
pulser operation settings and sends that information to the pulser motor
controller [550]. The
pulser motor controller [550] adjusts the stepper motor [310] current draw,
response time,
acceleration, duration, revolution, etc. to correspond to the pre-programmed
pulser settings
[530] from the DSP [540]. The stepper motor [310] driven by the pulser motor
controller
[550] operates the pilot actuator assembly [335] from Fig. 1. The pilot
actuator assembly
[335], responding exactly to the pulser motor controller [550], opens and
closes the main
valve [190], from Fig. 1, in the very sequence as dictated by the DSP [540].
The main valve
[190] opening and closing creates pressure variations of the fluid pressure in
the drill string
on top of the bore pressure [510] which is created by the mud pump [500]. The
main valve
[190] opening and closing also creates pressure variations of the fluid
pressure in the
annulus of the drill string on top of the base line annulus pressure [520]
because the fluid
movement restricted by the main valve [190] affects the fluid pressure
downstream of the
pulser assembly [400] through the drill it jets into the annulus of the bore
hole. Both the
annulus pressure sensor [470] and the bore pipe pressure sensor [420]
detecting the pressure
variation due to the pulsing and the pump base line pressure sends that
information to the
DSP [540] which determines the necessary action to be taken to adjust the
pulser operation
based on the pre-programmed logic.
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=
Operation - operational pilot flow ¨ all when the pilot is in the closed
position;
The motor [310] rotates the rotary magnetic coupling [300] which transfers the
rotary
motion to linear motion of the pilot valve [260] by using an anti-rotation
block [290]. The
mechanism of the rotary magnetic coupling [300] is immersed in oil and is
protected from
the drilling fluid flow by a bellows [280] and a pilot flow shield [270]. When
the motor
[310] moves the pilot valve [260] forward [ upward in Figure 1] into the pilot
orifice [250],
the pilot fluid flow is blocked and backs up as the pilot fluid in the pilot
flow exit channel
[360], pilot flow inlet channel [230] and in the pilot flow upper annulus
[160] all the way
.. back to the pilot flow screen [130] which is located in the lower velocity
flow area due to
the larger flow area of the main flow [110] and pilot flow [100] where the
pilot flow fluid
pressure is higher than the fluid flow through the main orifice [180]. The
pilot fluid flow
[100] in the pilot flow exit channel [360] also backs up through the main
valve feed channel
[220] and into the main valve pressure chamber [200]. The fluid pressure in
the main valve
pressure chamber [200] is equal to the main flow [110] pressure, but this
pressure is higher
relative to the pressure of the main fluid flow in the main orifice [180] in
front portion of the
main valve [190]. This differential pressure between the pilot flow flow in
the main valve
pressure chamber (200) area and the main flow through the main orifice [180]
into the main
orifice (180) causes the main valve [190] to act like a piston and to move
toward closure
[still upward in Figure 1] causing the main orifice [180] to stop the flow of
the main fluid
flow [110] causing the main valve [190] to stop the main fluid flow [110]
through the main
orifice [180]. As the drilling fluid main flow [110] stops at the main valve
[190] its pressure
increases. Since the pilot flow lower annular[210] extends to the bore pipe
pressure inlet
[410] located in the pilot valve support block [330] the pressure change in
the pilot fluid
flow reaches the bore pipe pressure sensor [420] which transmits that
information through
the electrical connector [440] to the pulser control electronics DSP [450].
The pulser
controlling electronics DSP [450] together with pressure data from the annulus
pressure
sensor [470] adjusts the pilot valve operation based on pre-programmed logic
to achieve the
desired pulse characteristics.
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Opening operation
When the motor (310) moves the pilot valve [260] away [downward in Figure 1]
from the
pilot orifice [250] allowing the fluid to exit the pilot exit flow [320] and
pass from the pilot
flow exit channel [360] relieving the higher pressure in the main valve
pressure chamber
[200] this causes the fluid pressure to be reduced and the fluid flow to
escape. In this
instance, the main fluid flow [110] is forced to flow through the main orifice
[180] to push
open [downward in Figure 1] the main valve [190], thus allowing the main fluid
[110] to
bypass the main valve [190] and to flow unencumbered through the remainder of
the tool.
Pilot Valve in the Open Position
As the main flow [110] and the pilot flow [100] enter the main flow entrance
[150] and
combined flow through into the flow cone area [170], by geometry [decreased
cross-sectional area], the velocity of the fluid flow increases. When the
fluid reaches the
main orifice [180] the fluid flow velocity is increased [reducing the pressure
and increasing
the velocity] and the pressure of the fluid is decreased relative to the
entrance flows [main
area vs. the orifice area] [180]. When the pilot valve [260] is in the opened
position, the
main valve [190] is also in the opened position and allows the fluid to pass
through the main
orifice [180] and around the main valve [190], through the openings in the
main valve
support block [350] through the pilot valve support block [330] and
subsequently into the
main exit flow [340].
The information flow on the Pulser Control Flow Diagram in Fig. 5 details the
controllable
pulser operation sequence. The drilling fluid pump, known as the mud pump
[500] is
creating the flow with a certain base line pressure. That fluid pressure is
contained in the
entirety of the interior of the drill string [510], known as the bore
pressure. The bore pipe
pressure sensor [420] is sensing this pressure increase when the pumps turn
on, and sends
that information to the Digital Signal Processor (DSP) [540] which interprets
it. The DSP
[540] also receives information from the annulus pressure sensor [470] which
senses the
drilling fluid (mud) pressure as it returns to the pump [500] in the annular
(outside) of the
drill pipe [520]. Based on the pre-programmed logic [530] in the software of
the DSP [540],
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and on the input of the two pressure sensors [420, 470] the DSP [540]
determines the correct
pulser operation settings and sends that information to the pulser motor
controller [550]. The
pulser motor controller [550] adjusts the stepper motor [310] current draw,
response time,
acceleration, duration, revolution, etc. to correspond to the pre-programmed
pulser settings
.. [530] from the DSP [540]. The stepper motor [310] driven by the pulser
motor controller
[550] operates the pilot actuator assembly [335] as shown in Fig. 1. The pilot
actuator
assembly [335], responds directly to the pulser motor controller [550], and
opens and closes
the main valve [190], again shown in Fig. 1, in the sequence dictated by the
DSP [540]. The
main valve [190] opening and closing creates pressure variations of the fluid
pressure in the
.. drill string in addition to the bore pressure [510] which is created by the
mud pump [500].
The main valve [190] opening and closing also creates pressure variations or
fluctuations of
the fluid pressure in the annulus of the drill string in addition to the base
line annulus
pressure [520] because the fluid movement restricted by the main valve [190]
affects the
fluid pressure downstream of the pulser assembly [400] through the drill as
the fluid jets into
.. the annulus of the bore hole. Both the annulus pressure sensor [470] and
the bore pipe
pressure sensor [420] detect the pressure variations exhibited by the pulsing
pressures and
the pump base line pressure. These variations provide signals that are sent as
data
information to the DSP [540] that determines the necessary action to be taken
to adjust the
pulser operation based on any pre-programmed logic provided.
DETAILED DESCRIPTION
The present invention will now be described in greater detail and with
reference to the
accompanying drawings. With reference now to Figure 1, the device illustrated
produces
pressure pulses for pulsing of the pulser within a main valve actuator
assembly of the flow
throttling device (FTD) in the vertical upward and downward direction using
drilling fluid
that flows through a tubular rental collar and an upper annulus which houses
the pilot flow.
There is a flow cone secured to the inner diameter of a hang off collar with
major
assemblies of the MWD that include a pilot flow screen assembly, a main valve
actuator
assembly, and a pilot actuator assembly.
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To enable the pulser to move in a pulsing upward and downward direction, the
passage of
the main flow of the drilling fluid flows through the pilot flow screen into
the main flow
entrance then into the flow cone section and through the main orifice and main
valve past
the main valve pressure chamber, past the seals, and finally into and through
the main valve
.. support block with the flow seal guide.
At this point, the initial drilling fluid combines with the pilot exit fluid
and together results
in the exit flow of the main fluid. The pilot fluid flow continues flowing
through the pilot
flow screen and into the pilot flow screen chamber then through the pilot flow
upper annulus
section, the pilot flow lower annulus section and into the pilot flow inlet
channel where the
fluid flows upward into the main valve feed channel until it reaches the main
valve pressure
chamber causing upward motion of the pulser. There, the fluid flows back down
the main
valve feed channel through the pilot flow exit channel and through the pilot
orifice and pilot
valve at which point the fluid exits the pilot area where it flows over the
pilot flow shield
and combines with the main flow to comprise the main exit flow as it exits the
pilot valve
support block and flows down both sides of the rotary magnetic coupling,
outside the
magnetic pressure cup and eventually past the drive shaft and the motor.
In operation to accomplish the task of providing for the pilot to attain the
closed position, the
motor rotates the rotary magnetic coupling transfers rotary motion to linear
motion of the
pilot valve by using an anti-rotation block. The mechanism of the rotary
magnetic coupling
is protected from the fluid flow by the use of a bellows and a pilot flow
shield. When the
motor moves the pilot valve forward ¨ upward into the pilot orifice ¨the pilot
valve blocks
and backs up the pilot fluid in the pilot flow exit channel, the pilot flow
inlet channel, and in
the pilot flow upper annulus, such that the fluid back up and reaches all the
way back to the
pilot flow screen (which is located in the lower velocity flow area due to the
geometry of the
larger flow area of the main flow and pilot flow sections such that the pilot
flow fluid
pressure is higher than the fluid flow through the main orifice).
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The pilot fluid flow in the pilot flow exit channel also backs up through the
main valve feed
channel and into the main valve pressure chamber. The fluid pressure in the
main valve
pressure chamber is now equal to the main flow pressure but the fluid pressure
is higher
relative to the pressure of the main fluid flow in the main orifice in the
front portion of the
main valve. The differential pressure between the pilot flow and the main flow
through the
main orifice causes the main valve to act like a piston and moves toward
closure of the main
orifice (upward direction in the Figures provided), thereby causing the main
valve to provide
a stoppage of the flow of the main fluid flow within the main orifice.
In another embodiment, the MWD device utilizes a turbine residing near and
within the
proximity of a flow diverter. The flow diverter diverts drilling mud in an
annular flow
channel into and away from the turbine blades such that the force of the
drilling mud causes
the turbine blades and turbine to rotationally spin around an induction coil.
The induction
coil generates electrical power for operating the motor and other
instrumentation mentioned
previously. The motor is connected to the pilot actuator assembly via a drive
shaft. The pilot
actuator assembly comprises a magnetic coupling and pilot assembly. The
magnetic
coupling comprises outer magnets placed in direct relation to inner magnets
located within
the magnetic pressure cup or magnetic coupling bulkhead. The magnetic coupling
translates
the rotational motion of the motor, via the outer magnets to linear motion of
the inner
magnets via magnetic polar interaction. The linear motion of the inner magnets
moves the
pilot assembly, comprising the pilot shaft, and pilot valve, linearly moving
the pilot into the
pilot seat. This action allows for closing the pilot seat, pressurizing the
flow throttling
device, closing the flow throttling device orifice, thereby generating a
pressure pulse.
Further rotation of the motor, drive shaft, via the magnetic coupling, moves
the pilot
.. assembly and pilot away from the pilot seat, depressurizing the flow
throttling device sliding
pressure chamber and opening the flow throttling device and completing the
pressure pulse.
Identical operation of the pilot into and out of the pilot seat orifice can
also be accomplished
via linear to linear and also rotation to rotation motions of the outer
magnets in relation to
the inner magnets such that, for example, rotating the outer magnet to rotate
the inner
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=
magnet to rotate a (rotating) pilot valve causing changes in the pilot
pressure, thereby
pushing the FTD (flow throttling device) up or down.
Unique features of the pulser include the combination of middle and lower
inner flow
channels, flow throttling device, bellows, and upper and lower flow connecting
channels
possessing angled outlet openings that helps create signals transitioning from
both the sealed
[closed] and unsealed (open) positions. Additional unique features include a
flow cone for
transitional flow and a sliding pressure chamber designed to allow for
generation of the
pressure pulses. The flow throttling device slides axially on a pulser guide
pole being pushed
by the pressure generated in the sliding pressure chamber when the pilot is in
the seated
position. Additional data (and increased bit rate) is generated by allowing
the fluid to
quickly back flow through the unique connecting channel openings when the
pilot is in the
open position. Bi-directional axial movement of the poppet assembly is
generated by
rotating the motor causing magnets to convert the rotational motion to linear
motion which
opens and closes the pilot valve. The signal generated provides higher data
rate in
comparison with conventional pulsers because of the bi-directional pulse
feature. Cleaner
signals are transmitted because the pulse is developed in near-laminar flow
within the
uniquely designed flow channels and a water hammer effect due to the small
amount of time
required to close the flow throttling device.
The method for generating pressure pulses in a drilling fluid flowing downward
within a
drill string includes starting at an initial first position wherein a pilot
(that can seat within a
pilot seat which resides at the bottom of the middle inner flow channel)
within a lower inner
flow channel is not initially engaged with the pilot seat. The pilot is held
in this position
with the magnetic coupling. The next step involves rotating the motor causing
the magnetic
fields of the outer and inner magnets to move the pilot actuator assembly
thereby moving the
pilot into an engaged position with the pilot seat. This motion seals a lower
inner flow
channel from the middle inner flow channel and forces the inner fluid into a
pair of upper
connecting flow channels, expanding the sliding pressure chamber, causing a
flow throttling
device to move up toward a middle annular flow channel and stopping before the
orifice
CA 2896287 2019-04-29
seat, thereby causing a flow restriction. The flow restriction causes a
pressure pulse or
pressure increase transmitted uphole. At the same time, fluid remains in the
exterior of the
lower connecting flow channels, thus reducing the pressure drop across the,
pilot seat. This
allows for minimal force requirements for holding the pilot in the closed
position. In the
.. final position, the pilot moves back to the original or first position away
from the pilot
orifice while allowing fluid to flow through the second set of lower
connecting flow
channels within the lower inner flow channel. This results in evacuating the
sliding pressure
chamber as fluid flows out of the chamber and back down the upper flow
connecting
channels into the middle inner flow channel and eventually into the lower
inner flow
channel. As this occurs, the flow throttling device moves in a downward
direction to open
along the same direction as the flowing drilling fluid until motionless. This
decreases the
FTD created pressure restriction of the main drilling fluid flow past the flow
throttling
device orifice completing the pulse.
.. An alternative embodiment includes the motor connected to a drive shaft
through a
mechanical device such as a worm gear, barrel cam face cam or other mechanical
means for
converting the rotational motion of the motor into linear motion to propel the
pilot actuator
assembly.
Opening operation
When the pilot valve moves away (downward in the vertical direction) into the
pilot orifice
allowing the fluid to flow through the pilot exit and pass from the pilot flow
exit channel
causing relief of the higher pressure in the main valve pressure chamber. This
allows for
the pressure to be reduced and the fluid to escape the chamber. The fluid is
then allowed to
flow into the main fluid flow and flow through the main orifice pushing open
(downward) or
opening the main valve, thus allowing the main fluid to by pass the main valve
and to flow
unencumbered through the remainder of the tool.
When the main flow and pilot flow enters the main flow entrance and flows
through into the
flow cone area where the velocity of the fluid flow increases such that the
fluid reaches the
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CA 2896287 2019-04-29
main orifice and the fluid flow velocity is increased (reducing the pressure
and increasing
the velocity of the fluid). The pressure of the fluid is decreased relative to
the entrance
flows (main area vs. the orifice area). When the pilot valve is in the opened
position, the
main valve is also in the open position and allows the fluid to pass through
the main orifice
and around the main valve and through the openings in the main valve support
block
allowing for the fluid to flow through the opening of the pilot and through
the pilot valve
support block. Subsequently the fluid flows into the main exit flow channel.
With reference now to Figure 1, the device illustrated produces pressure
pulses in drilling
fluid flowing through a tubular drill collar and upper annular drill collar
flow channel. The
flow cone is secured to the inner diameter of the drill collar. The
centralizer secures the
lower portion of the pulse generating device and is comprised of a non-
magnetic, rigid, wear
resistant material with outer flow channels.
These conditions provide generation of pulses as the flow throttling device
reaches both the
closed and opened positions. The present invention allows for several sized
FTD's to be
placed in a drilling collar, thereby allowing for different flow restrictions
and/or frequencies
which will cause an exponential increase in the data rate that can be
transmitted up hole.
Positioning of the main valve actuator assembly within the drill collar and
utilizing the flow
cone significantly decreases the turbulence of the fluid and provides
essentially all laminar
fluid flow. The linear motion of the flow throttling device axially is both up
and down
(along a vertical axial and radial direction without the use of a guide pole).
Conventional pulsers require adjustments to provide a consistent pulse at
different pressures
and flow rates. The signal provided in conventional technology is by a pulse
that can be
received up hole by use of a pressure transducer that is able to differentiate
pressure pulses
(generated downhole). These uphole pulses are then converted into useful
signals providing
information for the oilfield operators, such as gamma ray counts per second,
azimuth, etc.
Another advantage of the present invention is the ability to create a clean
[essentially free of
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noise] pulse signal that is essentially independent of the fluid flow rate or
pressure within the
drill collar. The present invention thereby allows for pulses of varying
amplitudes (in
pressure) and frequencies to significantly increase the bit rate.
An additional embodiment of the present invention includes a system comprising
a
controllable pulser that operates sequentially within a downhole assembly such
as a drill
pipe, that enhances operational efficiency in the removal of hydrocarbon
deposits, where the
system comprises; a fluid, fluid flow, and a fluid drilling pump which when
combined
creates fluid flow into a bore pipe annulus such that a base line bore pipe
pressure is created
and such that fluid flow and bore pipe pressure is contained entirely within a
drill string and
wherein bore pipe pressure increases and is measured with one or more pressure
sensors for
sensing bore pipe pressure such that pressure sensor(s) send information to a
digital signal
processor (DSP) that receives information in the form of digital data from
said pressure
sensor(s), and wherein pulser utilize computerized instructional software and
hardware
components included in the digital signal processor (DSP) so that controllable
sequential
operation of the pulser is obtained utilizing one or more pressure sensors
located within a
bore pipe annulus located within an outer annular portion of the drill pipe.
The pre-programmed logic is embedded within the software components of the DSP
such
that the input data supplied to the DSP by one or more pressure sensors
correctly
determines pulser operation settings allowing for the sending of data that is
subsequently
received and interpreted by the DSP for controlling a pulser motor controller,
wherein the
motor controller controls adjustment of a stepper motor's current draw,
response time,
acceleration, duration, and revolutions corresponding with pre-programmed
pulser settings
provided by the software components of the DSP and wherein pulses are
developed with a
pilot actuator assembly that identically match the pulses of the pulser motor
controller and
operates the opening and closing of a main valve in a sequence dictated by the
DSP, thereby
creating pressure variations of the fluid pressure resulting from fluid
flowing within the drill
string and within the bore pipe.
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The main valve opens and closes, thereby creating pressure variations of the
fluid pressure
in the annulus of the drill string in addition to the base line bore pipe
pressure due to fluid
flow movement restricted by the main valve, wherein the fluid pressure is also
affected
downstream of the pulser assembly as the fluid flows through a drill bit and
jets within said
bore hole pipe annulus.
While the present invention has been described herein with reference to a
specific exemplary
embodiment thereof, it will be evident that various modifications and changes
may be made
thereto without departing from the broader spirit and scope of the invention
as set forth in
.. the appended claims. The specification and drawings included herein are,
accordingly to be
regarded in an illustrative rather than in a restrictive sense.
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