U.S. patent application number 14/692377 was filed with the patent office on 2016-10-27 for pressure pulse reach extension technique.
The applicant listed for this patent is Schlumberger Technology Corporation. Invention is credited to Ilia Gotlib, Lawrence J. Leising, Shunfeng Zheng.
Application Number | 20160312559 14/692377 |
Document ID | / |
Family ID | 57147478 |
Filed Date | 2016-10-27 |
United States Patent
Application |
20160312559 |
Kind Code |
A1 |
Gotlib; Ilia ; et
al. |
October 27, 2016 |
Pressure Pulse Reach Extension Technique
Abstract
A pressure pulse tool and techniques that allow for a
reciprocating piston at a frequency independent of a flow rate of
fluid which powers the reciprocating. The architecture of the tool
and techniques employed may take advantage of a Coand{hacek over
(a)} or other implement to alternatingly divert fluid flow between
pathways in communication with the piston in order to attain the
reciprocation. Frequency of reciprocation may be between about 1 Hz
and about 200 Hz or other suitably tunable ranges. Once more, the
frequency may be enhanced through periodic exposure to annular
pressure. Extended reach through use of such a pressure pulse tools
and techniques may exceed about 2,000 feet.
Inventors: |
Gotlib; Ilia; (Westlake,
OH) ; Zheng; Shunfeng; (Katy, TX) ; Leising;
Lawrence J.; (Missouri City, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schlumberger Technology Corporation |
Sugar Land |
TX |
US |
|
|
Family ID: |
57147478 |
Appl. No.: |
14/692377 |
Filed: |
April 21, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 19/22 20130101;
E21B 28/00 20130101; E21B 23/14 20130101 |
International
Class: |
E21B 28/00 20060101
E21B028/00; E21B 17/00 20060101 E21B017/00 |
Claims
1. A method of advancing a downhole conveyance device through a
deviated section of a well, the method comprising: deploying the
downhole conveyance device into the well with a fluid flowing
therethrough at a given rate; alternatingly diverting the fluid
flow between pathways of a pressure pulse tool for reciprocating a
piston thereof at a given frequency independent of the given rate;
and advancing the conveyance device through the deviated section
during the reciprocating of the piston and to a target location in
the well.
2. The method of claim 1 wherein the reciprocating of the piston
periodically interrupts fluid flow to generate pressure pulses as
an aid to attaining the extended reach.
3. The method of claim 1 wherein the alternatingly diverting of the
fluid flow between pathways further comprises alternatingly
deflecting a diverting mechanism of the tool between the pathways
to guide the fluid flow via a Coand{hacek over (a)} effect.
4. The method of claim 1 further comprising periodically exposing
the reciprocating piston to annular pressure in the well.
5. The method of claim 1 further comprising tuning the given
frequency to between about 1 Hz and about 200 Hz.
6. The method of claim 1 further comprising performing an
application in the well at the target location with an application
tool coupled to the downhole conveyance device.
7. A pressure pulse tool for a downhole device, the device
configured for use in a well and to carry a fluid at a given flow
rate, the tool comprising: a housing coupled to the downhole device
for directing the fluid therethrough; and a piston located within
the housing for shifting at a given frequency independent of the
flow rate.
8. The pressure pulse tool of claim 7 wherein the given frequency
is between about 1 Hz and about 200 Hz.
9. The pressure pulse tool of claim 7 wherein the housing defines a
primary channel in fluid communication with an uphole bore of the
downhole device for the directing of the fluid, the tool further
comprising: a nozzle-shaped region of the housing in communication
with the primary channel, the nozzle-shaped region having a neck
leading to first and second fluid pathways in fluid communication
with the piston; a diverting mechanism at least partially located
within the neck for guiding fluid from the primary channel and
alternatingly between the first and second pathways for the
shifting thereof at the given frequency; and a controller for
controlling a rate of the alternating of the diverting mechanism
between the pathways.
10. The pressure pulse tool of claim 9 wherein the piston is in
periodic fluid communication with an annular port to the well.
11. The pressure pulse tool of claim 9 wherein the diverting
mechanism is a Coand{hacek over (a)} implement.
12. The pressure pulse tool of claim 11 wherein the Coand{hacek
over (a)} implement is one of a piezo-based implement and a
magnetically actuated implement.
13. The pressure pulse tool of claim 12 wherein the piezo-based
implement comprises piezoceramic material layers.
14. The pressure pulse tool of claim 12 wherein the magnetically
actuated implement comprises north and south polarized end
portions, the tool further comprising a magnetic coil located at
least partially in the neck and adjacent the end portions.
15. An oilfield assembly for use at an oilfield, the assembly
comprising: a conveyance device; a bottom hole assembly coupled to
the conveyance device and having an application tool for use at a
target location in a well; and a pressure pulse tool of the bottom
hole assembly, the tool having a housing in fluid communication
with the conveyance device for directing fluid therethrough at a
given flow rate for reciprocating a piston at a frequency
independent of the given flow rate.
16. The oilfield assembly of claim 15 wherein the conveyance device
is one of tubing string, coiled tubing, drill pipe, casing,
production tubing and a liner.
17. The oilfield assembly of claim 15 wherein the pressure pulse
tool comprises a Coand{hacek over (a)} element for directing fluid
interchangeably between pathways at a given rate to effect the
frequency of the reciprocating of the piston, the bottom hole
assembly further comprising: a downhole power source for the
Coand{hacek over (a)} element; and a controller for regulating the
rate of fluid interchange between the pathways.
18. The oilfield assembly of claim 17 further comprising a
telemetric line coupled to the controller and to surface equipment
at a surface of the oilfield to allow operator direction of the
controller.
19. The oilfield assembly of claim 18 wherein the telemetric line
is a fiber optic line.
Description
BACKGROUND
[0001] Exploring, drilling and completing hydrocarbon and other
wells are generally complicated, time consuming and ultimately very
expensive endeavors. In recognition of these expenses, added
emphasis has been placed on maximizing productivity over the course
of the well's life. Thus, well logging, profiling and monitoring of
well conditions are playing an ever increasing role in oilfield
operations. Similarly, more actively interventional applications
are regularly called for such as clean-out applications, opening or
closing valves and sliding sleeves or any number of other maneuvers
targeting maximized recovery and well life.
[0002] In addition to regular intervention for sake of monitoring
and/or managing well operations, the well itself may also be of
fairly sophisticated architecture. For example, in an attempt to
maximize recovery from the reservoir and extend the useful life of
the well, it may be of a fairly extensive depth and tortuous
configuration. This may include overall depths in the tens of
thousands of feet range. Once more, such wells may include extended
horizontal or deviated sections of several thousand feet. For
example, it is becoming increasingly more common for wells to
include horizontal sections that are 10-15,000 feet long or more.
As a result, interventions through such wells are becoming of ever
increasing difficulty as noted below.
[0003] The above described interventions through deviated wells are
generally achieved by way of coiled tubing, pipe or other suitable
form of rigid or semi-rigid well access line or conveyance. Thus, a
logging, clean-out, shifting or other application tool may be
driven through deviated well sections. Unfortunately, after a few
thousand feet of conveyance through such a section, the tubing will
generally begin to undergo sinusoidal buckling. This is followed by
helical buckling, and soon thereafter, helical lock of the line
within the deviated section such that further advancement is
impossible. As a practical matter, without added measures being
taken, it is unlikely that conventional coiled tubing would be able
to reach beyond about 2-6,000 feet into a horizontal well section.
Of course, this is problematic where the target location for the
application at hand is at a location beyond, 6,000 feet, for
example. Further, this problem has become increasingly common given
the ever increasing depths of wells and deviated well sections.
[0004] Various techniques or conveyance aids have been developed to
help extend the reach of coiled tubing through such deviated
sections such that the appropriate application tool may arrive at
the desired target location. For example, typical coiled tubing of
about 1.5 inches in diameter may be replaced with one of 2-3 inches
in diameter. This larger tubing may noticeably extend reach.
Unfortunately, use of such heavier tubing presents added equipment
related compatibility issues at the oilfield surface. For example,
this may require a specially built coiled tubing spool, injector,
and other high dollar machinery to accommodate the heavier tubing.
Thus, as an alternative, a coiled tubing may be utilized that is of
a variable wall thickness, for example, being thinner near the
downhole end. This may reduce some of the weight-related issues.
However, the extent of the added reach remains unlikely to be more
than a few hundred feet.
[0005] In conjunction with or in addition to utilizing larger
coiled tubing, a coiled tubing straightener may be utilized. That
is, as the tubing is being injected into the well, it may be
simultaneously straightened upon entry. With this technique, wound
coiled tubing is not only unwound from having been stored on a
spool, but it is actually bent in a bit opposite the unwound
direction. Thus, the coiled tubing entering the well is even
straighter and capable of reaching a bit further into the well.
Unfortunately, the extended reach is unlikely to be by more than a
few hundred feet. Once more, utilizing a straightener in this
fashion introduces fatigue on the coiled tubing, thereby reducing
its overall effective life.
[0006] Alternatively, extending reach may be furthered by the
addition of a friction reducer, introduced through the coiled
tubing during conveyance, particularly through a deviated section.
As a result, an added 10-15% or so of coiled tubing reach may be
realized. In circumstances where the deviated well section is under
about 3,000-5,000 feet, this may make all the difference in
allowing the coiled tubing to fully traverse the section. However,
as deviated well sections become longer and longer, use of a
friction reducer in this manner is unlikely to do the trick. Once
more, the use of a friction reducer introduces the expense of a
friction fluid which may or may not be compatible with the fluid
and environment of the ongoing coiled tubing application.
[0007] More sophisticated measures may also be undertaken in an
effort to extend the reach of coiled tubing or other conveyance
through a horizontal well section. For example, a downhole tractor
may be used to pull the coiled tubing through the deviated well
section. That is, well tractors may be attached to the coiled
tubing, positioned in the well, and employed to advance downhole,
pulling the coiled tubing through the well including such
problematic deviated sections. Such tractoring may be fairly
effective. Indeed, it would not be unreasonable to expect to be
able to traverse more than 6,000 feet through a deviated section in
this manner. Unfortunately, the cost of tractoring is often
exorbitant. Once more, substantial time is spent rigging up
tractoring equipment at the oilfield surface not to mention the
expense involved in tractor retrieval should the tractor become
stuck downhole which is not an uncommon occurrence.
[0008] As opposed to tractoring, another somewhat sophisticated
extended reach technique may be employed by way of pressure pulse.
For example, a fluidic switch may be incorporated into a downhole
tool and utilized to provide a vibration to the advancing tubing in
order to extend its reach. While this may not extend reach to the
degree of utilizing a tractor, unlike other extended reach methods
described above, pressure pulse is likely to reliably provide a
reach extension of 1,000 feet or more without the degree of expense
and complexity required during tractoring. Unfortunately, however,
the natural operation of a fluidic switch is such that the
vibrational frequency utilized is limited to practical geometry and
flow-rate parameters that may not easily be manipulated.
SUMMARY
[0009] A pressure pulse tool for a downhole conveyance device is
detailed herein. The conveyance device may be deployed from an
oilfield with a fluid flow directed therethrough at a given rate.
Further, the tool may include a housing coupled to the device for
directing the fluid flow therethrough. A piston located within the
housing may be configured to shift at a frequency directed by the
operator at the oilfield surface in a manner that is independent of
the flow rate. The pressure pulse tool may be incorporated into
wellbore devices other than conveyance devices. In one embodiment,
the tool may be a fluidic switch operating to direct the fluid flow
and ultimately the frequency by taking advantage of a Coand{hacek
over (a)} effect for the flowing fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Implementations of various structure and techniques will
hereafter be described with reference to the accompanying drawings.
It should be understood, however, that these drawings are
illustrative and not meant to limit the scope of claimed
embodiments.
[0011] FIG. 1A is a side cross-sectional view of an embodiment of a
pressure pulse tool for a downhole conveyance.
[0012] FIG. 1B is a schematic view of an embodiment of a
piezobender of the pressure pulse tool of FIG. 1A.
[0013] FIG. 2 is a side partially sectional view of a downhole
conveyance accommodating the pressure pulse tool of FIG. 1A.
[0014] FIG. 3 is an overview of an oilfield with a well
accommodating the downhole conveyance of FIG. 2 therein.
[0015] FIG. 4 is an enlarged side cross-sectional view of a portion
of another embodiment of a pressure pulse tool for a downhole
conveyance.
[0016] FIG. 5A is a side cross-sectional view of yet another
embodiment of a pressure pulse tool for a downhole conveyance.
[0017] FIG. 5B is a chart depicting positive and negative pressure
pulse magnitudes attainable from the tool of FIG. 5A.
[0018] FIG. 6 is a flow-chart summarizing an embodiment of
employing a pressure pulse tool in a downhole conveyance for an
application in a well.
DETAILED DESCRIPTION
[0019] Embodiments are described with reference to certain downhole
applications utilizing a pressure pulse tool as an aid to the
advancement of a downhole conveyance, for example, through a
deviated well section. Specifically, the pressure pulse tool may be
utilized to provide vibration assistance and reduce the probability
of helical lockup for a conveyance by reducing friction between the
conveyance and the well. In the embodiments depicted, the
conveyance is coiled tubing used to deliver a cleanout tool to a
target location in a deviated or horizontal well section. Thus,
debris may be cleaned out for sake of enhancing production from the
area of the target location. However, a variety of other
applications may benefit from pressure pulse tool embodiments and
techniques as detailed herein. For example, the conveyance may be
coiled tubing, drill pipe, casing or any other forcible tubular
conveyance. Indeed, other forms of wellbore devices may also
utilize such pressure pulse tools. So long as a pressure pulse tool
is utilized in which vibration is powered by a fluid flow while
displaying a vibrational frequency independent of the fluid flow
rate, appreciable benefit may be realized. Throughout this
document, a "conveyance device" is referenced to a tubing string,
such as coiled tubing, drill pipe, casing, production tubing or
liner, which is used to enter the wellbore, and perform downhole
operation.
[0020] Referring now to FIG. 1A, a side cross-sectional view of an
embodiment of a pressure pulse tool 100 is shown. With added
reference to FIG. 2, the tool 100 includes a housing configured to
receive a fluid flow 155 through a primary channel 150 that is in
fluid communication with an uphole bore 215 of a downhole
conveyance such as the coiled tubing 210. As used herein the term
"pressure pulse tool" is used to apply to a tool 100 that employs a
fluidic switch or fluidic switch architecture such as that depicted
here in FIG. 1A or as shown in the embodiments of FIGS. 4 and/or
5A.
[0021] More specifically, the pressure pulse tool 100 includes
fluidic switch architecture in the form of the noted primary
channel 150 which receives a fluid flow 155 and a secondary channel
which receives a portion of fluid flow from 155 and directs it
toward a neck 157 that splits into different fluid pathways 158,
159. Further, the portion of the fluid flow 155 which is drawn into
the neck 157 will tend to initially divert to one of the pathways
158, 159. This is a result of what is referred to as the
Coand{hacek over (a)} effect, or the tendency of a fluid flow to
maintain physical attraction to a surface during flow. By way of
example, in the embodiment shown, the diverted flow is shown
entering the lower pathway 159 of the depiction. This in turn will
act upon a piston 175 that is in communication with the pathway 159
and force it to move in a corresponding direction, indicated by an
arrow 176.
[0022] At the same time, however, the piston 175 is also in
communication with the other pathway 158 at an opposite side
thereof. Thus, once diverted flow is forced into this upper pathway
158, the movement of the piston 175 will change direction and a
cycle of piston reciprocation will be attained. Reciprocation of
the piston 175 in the directions 176 may take place while also
resulting in intermittent fluid flow 155 through the entirety of
the tool 100. For example, in the embodiment shown, the piston 175
includes a passage 151 that is aligned with the primary channel 150
at an uphole side thereof while also in turn being cyclically
ported to an outlet 153 and back into communication with the
channel 150 at a downhole side thereof. Regardless, ongoing
reciprocation of the piston 175 as described results in vibration
that allows the pressure pulse tool 100 to serve as an aid to
advancement of a downhole conveyance such as the coiled tubing 210
shown in FIGS. 2 and 3. More specifically, as the piston
reciprocates, it intermittently interrupts fluid flow through the
primary channel 150, which generates a water hammer effect of
vibrating "pressure pulses". This water hammer effect causes
vibration along the coiled tubing 210 to which the pressure pulse
tool 100 is attached.
[0023] As a practical matter, the indicated vibrations aid in tool
advancement through a well 380 (again, see FIG. 3). Further, the
frequency and effectiveness of these vibrations via the
reciprocating piston 175 is thus, determined by the rate at which
the fluid flow 155 through the neck 157 is alternated between the
different pathways 158, 159 at either side of the piston 175.
However, in the embodiment shown, unlike a conventional fluidic
switch, the frequency of vibration obtained from the reciprocating
piston 175 is achieved independent of the rate of the fluid flow
155. That is, while sufficient fluid flow 155 is available to drive
the reciprocation, the actual rate at which fluid flow 155 through
neck 157 is alternatingly switched between pathways 158, 159 is
attained through a separate diverting mechanism 140 as detailed
further below.
[0024] The diverting mechanism 140 is used to actively direct the
portion of the fluid flow 155 travelling through the neck 157 to
one of the two pathways 158, 159. In the embodiment shown, the
diverting mechanism 140 is a Coand{hacek over (a)} implement. That
is, the mechanism 140 is a physical implement tailored to take
advantage of the tendency of the fluid to travel along a surface
when flowing. So, for example, as shown in FIG. 1A, the mechanism
140 is deflected slightly downward and the corresponding fluid flow
155 is directed downward and through the lower pathway 159.
However, the diverting mechanism 140 is coupled to a controller 130
and a power source 120 to govern the frequency with which the
diverting mechanism alternates between the upper 158 and lower 159
pathways. For example, in the embodiment shown, the controller 130
is a conventional downhole circuit board powered by a standard
lithium battery power source 120. Thus, without even requiring a
power line, a frequency control signal from an oilfield surface 300
may be sent over a fiber optic telemetric line 110 and modulated by
the controller 130 to dictate the rate at which the diverting
mechanism 140 moves from pathway 159 to pathway 158 (see FIG. 3).
Indeed, with added reference to FIG. 1B, a low power, variable
frequency mode of alternatingly moving the diverting mechanism 140
between pathways 158, 159 is described where the mechanism 140 is a
piezobender.
[0025] With specific reference to FIG. 1B, a schematic view of an
embodiment of a piezo-based implement is shown for use as the
diverting mechanism 140 of FIG. 1A. In this embodiment, the
mechanism 140 may be made up of multiple layers of piezoceramic
material having differently tailored polarizations. So, for
example, when a voltage is applied one layer 142 may expand while
the other 144 contracts, resulting in a deflection as shown (see
arrow 147). In the depicted example of FIGS. 1A and 1B, the
piezo-based bender implement 140 may have a natural orientation
downward (e.g. and toward the lower pathway 159 as shown in FIG.
1A). However, repeated intermittent application of voltage across
the implement 140 may result in a repeated deflection upward (e.g.
and toward the upper pathway 158). When this rate of deflection is
governed by the controller 130 at a set frequency, the
reciprocation of the piston 175 of FIG. 1 may be established. Of
course, the piezo-based form of the mechanism 140 may be
differently configured, for example with more or fewer layers 142,
144, active deflection in both directions, or other conventional
piezo options employed.
[0026] Use of a piezo-based implement as the diverting mechanism
140 may be particularly beneficial for use in the downhole
environment. That is, a variable frequency may be readily achieved
with low power requirements. For example, with no more than
intermittent supply of well under a volt from the power supply 120,
the mechanism 140 may be directed by the regulator 130 to display a
frequency of 1 Hz-200 Hz or more. To maintain a peak pressure
pulse, this is dramatically wider range and more controllable than
a conventional fluidic switch that relies solely on flow rate to
achieve a frequency By way of contrast, the embodiment of FIGS. 1A
and 1B may maintain a constant flow rate of, for example, 3 BPM
throughout while utilizing the diverting mechanism 140 to adjust
frequency to anywhere from 1 Hz to 200 Hz depending on operating
conditions. Variables of such operating conditions may include
downhole conditions themselves or the length of the coiled tubing
210 in the well 380 (see FIG. 3). Regardless, the enhanced ability
to adjust or tune the frequency as described may maximize the
effect of friction reduction for the pressure pulse tool 100. Of
course, these particular values are only exemplary as other flow
rates and frequencies may be employed in conjunction with the
described embodiments.
[0027] Referring now to FIG. 2, a side partially sectional view of
a downhole conveyance 210 is shown. In the embodiment shown, this
conveyance 210 is coiled tubing with a bottom hole assembly (BHA)
201 secured at the end thereof. For example, the coiled tubing
conveyance 210 may be utilized to forcibly deliver the BHA 201 to a
target location in a well 380 as depicted in FIG. 3. In this way an
application may be run at the target location, for example, a
cleanout application with a cleanout tool 275 of the BHA 201.
Regardless, the BHA 201 is outfitted with the above described
pressure pulse tool 100 of FIG. 1A. Therefore, an aid to reach
extension is provided making it more likely that the application
tool 275 will be able to traverse a deviated well 380 to the extent
required in order to reach the target location (again, see FIG.
3).
[0028] With added reference to FIGS. 1A and 1B, along with FIG. 2
here, the pressure pulse tool 100 is shown coupled to the coiled
tubing conveyance 210 with the telemetric line 110 traversing the
bore 215 of the conveyance 210 in order to reach the tool 100.
Thus, as detailed hereinabove, vibrational frequency may be
governed by a diverting mechanism 140 within the tool 100. Power
requirements for the vibrating may be met by a flow of fluid 155
whereas power for the diverting mechanism 140 may be supplied by a
small power source 120 within the tool 100. However, in other
embodiments, power for the mechanism 140 may be drawn from a power
equipped version of the line 110. Additionally, power for the BHA
201, including for the mechanism 140 where so desired, may be
provided by a larger downhole battery package 225. For example, in
the embodiment shown, a logging tool 250 or the cleanout tool 275
may have functional components with power requirements to be met
from a downhole source and that exceed what is available from a
power source 120 such as that employed by the diverting mechanism
140.
[0029] Referring now to FIG. 3, an overview of an oilfield 300 is
shown with a well 380 accommodating the downhole conveyance 210 of
FIG. 2 therein. The well 380 may be defined by casing 385 as it
vertically traverses various formation layers 390, 395. Further, it
may extend several thousand feet through an uncased horizontal
section 387. Thus, in order to reach a target location for an
application in the horizontal section 387, added measures may be
taken. For example, as shown in FIG. 3, the conveyance 210 is
coiled tubing which may be forcibly advanced past a well head 375
and downhole by way of an injector 360.
[0030] As a matter of extending the reach further through the
horizontal section 387 than otherwise possible, the above described
pressure pulse tool 100 is also utilized. As indicated above,
embodiments of the tool 100 may be employed over a wider range of
frequencies due to the unique independent nature in which frequency
is attained independent of the particular rate of fluid flow
through the conveyance 210. As also indicated above, the extra
reach for the BHA 201 may include well over 2,000 feet of extended
reach as a result of the improved control of operating frequency
available to the tool 100. Once more, this may be achieved without
the requirement of tractoring or other larger and more complex
and/or less reliable equipment options. Indeed, the surface
equipment 325 for the conveyance 210 may even be mobile by way of a
coiled tubing truck 340 accommodating a support rig 350 as
shown.
[0031] Referring now to FIG. 4, an enlarged side cross-sectional
view of a portion of another embodiment of the pressure pulse tool
100 is shown. In this case, the fluidic switch architecture, which
is defined by a housing of the tool 100, remains but with the
operation of the diverting mechanism 140 actuated differently from
the embodiment depicted in FIGS. 1A and 1B. Specifically, in the
embodiment of FIG. 4, the diverting mechanism 140 still operates
under the principle of the Coand{hacek over (a)} effect but in this
case is magnetically actuated.
[0032] Continuing with reference to FIG. 4, a portion of the fluid
flow 155 entering into the tool 100 will travel through the nozzle
shaped region of the tool 100, across a neck 157 and into one of
two different pathways 158, 159. As detailed above, each of these
pathways 158, 159 are in fluid communication with opposite sides of
a piston 175 (see FIG. 1A). Thus, as flowing fluid is selectively
alternated between the pathways 158, 159 by the diverting mechanism
140, a vibration or pressure pulse is provided by the tool 100.
[0033] The frequency of the pressure pulse vibrations is dependent
upon the rate at which the diverting mechanism 140 is alternated
between the corresponding pathways 158, 159. As noted above, in the
embodiment shown, the diverting mechanism 140 is magnetically
actuated. Specifically, the controller 130 is electronically
coupled to a magnetic coil 400. The coil 400, in turn is provided
about a portion of the neck 157 which surrounds a polarized end of
the diverting mechanism 140. Specifically, the polarized end may
include north 437 and south 427 portions. Thus, alternating the
magnetic field in the coil 400 may induce deflection of the
mechanism 140 back and forth. As shown, this back and forth would
mean moving the diverting mechanism 140 back and forth between
alignment with one pathway 158 or another 159. Using the power
source 120 and controller 130 to guide deflective movement of the
mechanism 140 in a magnetic fashion may be particularly beneficial
in a controllability sense. That is, magnetic actuation is
generally reliable and effective even with such small scale
dimensions as are found in a pressure pulse tool 100 and components
such as the diverting mechanism 140.
[0034] Referring now to FIG. 5A, a side cross-sectional view of yet
another embodiment of the pressure pulse tool 100 is shown. In this
embodiment, the diverting mechanism 140 again takes advantage of
the Coand{hacek over (a)} effect. Indeed, the mechanism 140 may be
either be piezo-based as in the embodiment of FIGS. 1A and 1B or
magnetically actuated as in the embodiment of FIG. 4 described
above. However, in this case, the water hammer effect of vibration
during reciprocation of the piston 175 is enhanced by both positive
and negative peaks. That is, the piston 175 is not only exposed to,
and interrupting of, the primary channel 150 through the tool 100
but during reciprocation also provides an interrupted exposure that
allows for the egress of fluid out of the tool 100 to an annular
space 501 outside of the tool 100. Specifically, note the port 500
which provides reciprocating interrupted communication between an
annular space 501 and primary flow channel 150 (see also FIG.
3).
[0035] Referring now to FIG. 5B, a chart depicting positive and
negative pressure pulse magnitudes attainable from the tool of FIG.
5A is shown. With added reference to FIG. 3, the pressure within
the tool 100 and/or conveyance 210 may be substantial and
comparatively higher than the pressure within the annular space 501
of a well 380 at a given depth (e.g. 387). The impact of this
potential disparity in pressures, depending on the location of the
reciprocating piston 175, may be seen figuratively in a peak to
peak analysis as shown in FIG. 5B. Specifically, the additional
negative pressure pulse means that the overall pressure pulse
magnitude (peak to peak) would be higher than conventional pressure
tool, resulting in increased "water hammer effect" or vibration of
the conveyance device, and ultimately a more extended reach.
Regardless, in the embodiment shown, the diverting mechanism 140
remains independently directed through a controller 130 and is not
dependent on any particular fluid flow rate regardless of origin.
Thus, the range of frequencies that may be employed for the
embodiments of FIGS. 5A and 5B is again enhanced as with the
embodiments of FIGS. 1A and 1B (or FIG. 4).
[0036] Referring now to FIG. 6, a flow-chart is shown summarizing
an embodiment of employing a pressure pulse tool in a downhole
conveyance or other wellbore tool for an application in a well.
Specifically, as indicated at 615, the wellbore device may be
deployed into a well and advanced to a target location as noted at
630. This may be several thousand feet into a deviated well section
or in another challenging region of the well in terms of access.
Thus, as indicted at 645, a pressure pulse tool of a bottom hole
assembly may be operated as the wellbore device is advanced
downhole.
[0037] Operating the pressure pulse tool may include selectively
diverting a fluid flow through the tool between fluid pathways as
indicated at 660. This is done in a way that not only reciprocates
a piston at a given frequency but does so in a manner that the
frequency is independent of a flow rate of the fluid. In fact, the
reciprocating piston may even periodically divert the fluid to the
annulus to affect the overall peak to peak pressure pulse of the
tool and enhance the extended reach (see 675).
[0038] Embodiments described hereinabove include a pressure pulse
tool utilizing a fluidic switch to aid a wellbore device in
achieving improved extended reach through a deviated well. This is
achieved in a manner that avoids the complexity and expense of
tractoring equipment while at the same time providing a realistic
opportunity to provide extended reach of substantially beyond 1,000
feet. In fact, in contrast to more conventional vibration
assistance, fluidic switch embodiments and techniques detailed
herein may allow for a range of pressure pulse frequencies up to
about 200 Hz or more. Thus, extra extended reach of 2,000 feet or
more may be reliably achieved.
[0039] The preceding description has been presented with reference
to presently preferred embodiments. Persons skilled in the art and
technology to which these embodiments pertain will appreciate that
alterations and changes in the described structures and methods of
operation may be practiced without meaningfully departing from the
principle, and scope of these embodiments. Regardless, the
foregoing description should not be read as pertaining only to the
precise structures described and shown in the accompanying
drawings, but rather should be read as consistent with and as
support for the following claims, which are to have their fullest
and fairest scope.
* * * * *