U.S. patent application number 12/787026 was filed with the patent office on 2010-12-02 for system and method for estimating velocity of a downhole component.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. Invention is credited to Eric Sullivan, Tu Tien Trinh.
Application Number | 20100300755 12/787026 |
Document ID | / |
Family ID | 43218944 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100300755 |
Kind Code |
A1 |
Trinh; Tu Tien ; et
al. |
December 2, 2010 |
SYSTEM AND METHOD FOR ESTIMATING VELOCITY OF A DOWNHOLE
COMPONENT
Abstract
A system for estimating a velocity of a downhole component is
disclosed. The system includes: a sensor configured to produce a
sensor signal that is proportional to at least one of a position
and an acceleration of the downhole component; and a circuit in
communication with the sensor and configured to receive the sensor
signal and generate an output signal indicative of an instantaneous
velocity of the downhole component. A method of estimating a
velocity of a downhole component is also disclosed.
Inventors: |
Trinh; Tu Tien; (Houston,
TX) ; Sullivan; Eric; (Houston, TX) |
Correspondence
Address: |
CANTOR COLBURN LLP- BAKER HUGHES INCORPORATED
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
43218944 |
Appl. No.: |
12/787026 |
Filed: |
May 25, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61183371 |
Jun 2, 2009 |
|
|
|
Current U.S.
Class: |
175/40 |
Current CPC
Class: |
E21B 47/04 20130101;
E21B 45/00 20130101 |
Class at
Publication: |
175/40 |
International
Class: |
E21B 47/00 20060101
E21B047/00 |
Claims
1. A system for estimating a velocity of a downhole component, the
system comprising: a sensor configured to produce a sensor signal
that is proportional to at least one of a position and an
acceleration of the downhole component; and a circuit in
communication with the sensor and configured to receive the sensor
signal and generate an output signal indicative of an instantaneous
velocity of the downhole component.
2. The system of claim 1, wherein the sensor signal is a voltage
signal.
3. The system of claim 1, wherein the sensor is selected from at
least one of an accelerometer and a strain gauge.
4. The system of claim 1, wherein the sensor is an accelerometer
configured to generate an input voltage proportional to an
acceleration of the downhole component, and the circuit is an
integrator circuit.
5. The system of claim 4, wherein the integrator circuit is an
active integrator circuit having an operational amplifier.
6. The system of claim 1, wherein the sensor is a position sensor
configured to generate an input voltage proportional to a position
of the downhole component, and the circuit is a differentiator
circuit.
7. The system of claim 6, wherein the integrator circuit is an
active differentiator circuit having an operational amplifier.
8. The system of claim 1, wherein the component is a drill bit.
9. The system of claim 1, wherein the instantaneous velocity is
related to a rate of penetration (ROP) of the component.
10. The system of claim 1, wherein the sensor includes one or more
sensors positioned to measure at least one of the acceleration and
a change of the position of the downhole component along at least
one axis.
11. The system of claim 10, wherein the at least one axis extends
along a direction selected from at least one of an axial direction
parallel to a borehole, a radial direction perpendicular to the
axial direction, and a tangential direction perpendicular to the
radial and axial directions.
12. A method of estimating a velocity of a downhole component, the
method comprising: lowering a sensor into a borehole in an earth
formation, the sensor configured to produce a sensor signal that is
proportional to at least one of a position and an acceleration of
the downhole component; activating the sensor to generate the
sensor signal; and transmitting the signal to a circuit and
generating an output signal indicative of an instantaneous velocity
of the downhole component via the circuit.
13. The method of claim 12, wherein the sensor signal is a voltage
signal.
14. The method of claim 12, wherein the sensor is selected from at
least one of an accelerometer and a strain gauge.
15. The method of claim 12, wherein the sensor is an accelerometer
configured to generate an input voltage proportional to an
acceleration of the downhole component, and generating the output
signal includes integrating the input voltage over a selected
period of time via the circuit.
16. The method of claim 15, wherein integrating includes
integrating the input voltage with an active integrator circuit
having an operational amplifier.
17. The method of claim 12, wherein the sensor is a position sensor
configured to generate an input voltage proportional to a position
of the downhole component, and generating the output signal
includes differentiating the input voltage over a selected period
of time via the circuit.
18. The method of claim 17, wherein differentiating includes
differentiating the input voltage with an active differentiation
circuit having an operational amplifier.
19. The method of claim 12, wherein the instantaneous velocity is
related to a rate of penetration (ROP) of the component.
20. The method of claim 12, wherein lowering the sensor includes
drilling at least a portion of the borehole.
Description
BACKGROUND
[0001] In hydrocarbon exploration operations, well boreholes are
drilled by rotating a drill bit attached to a drillstring, and may
be bored vertically or bored in selected directions via geosteering
operations. Various downhole devices located in a bottomhole
assembly or other locations along the drillstring measure operating
parameters and formation characteristics, and include sensors for
determining the presence of hydrocarbons.
[0002] Various drilling parameters are monitored during drilling
operations to assess the progress of a drilling operation and the
performance of a drill bit. A drill bit's rate of penetration (ROP)
is a significant parameter measured to monitor drilling progress as
well as the presence of formation materials that affect the
drilling performance and degradation of the drill bit. ROP is
generally measured as an average over a selected period of time.
Such average ROP measurements may compromise the ability to assess
the actual ROP at any given moment and location during
drilling.
BRIEF DESCRIPTION OF THE INVENTION
[0003] A system for estimating a velocity of a downhole component
includes: a sensor configured to produce a sensor signal that is
proportional to at least one of a position and an acceleration of
the downhole component; and a circuit in communication with the
sensor and configured to receive the sensor signal and generate an
output signal indicative of an instantaneous velocity of the
downhole component.
[0004] A method of estimating a velocity of a downhole component
includes: lowering a sensor into a borehole in an earth formation,
the sensor configured to produce a sensor signal that is
proportional to at least one of a position and an acceleration of
the downhole component; activating the sensor to generate the
sensor signal; and transmitting the signal to a circuit and
generating an output signal indicative of an instantaneous velocity
of the downhole component via the circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The following description should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0006] FIG. 1 depicts an embodiment of a drilling and/or
geosteering system;
[0007] FIG. 2 is a circuit diagram illustrating an embodiment of a
circuit of the system of FIG. 1;
[0008] FIGS. 3A and 3B are circuit diagrams illustrating additional
embodiments of a circuit of the system of FIG. 1;
[0009] FIG. 4 is a circuit diagram illustrating another embodiment
of a circuit of the system of FIG. 1;
[0010] FIGS. 5A and 5B are circuit diagrams illustrating further
embodiments of a circuit of the system of FIG. 1; and
[0011] FIG. 6 is a flow chart providing an exemplary method of
estimating a velocity of a downhole component.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Referring to FIG. 1, an exemplary embodiment of a well
drilling and/or geosteering system 10 includes a drillstring 11
that is shown disposed in a borehole 12 that penetrates at least
one earth formation during a drilling operation and makes
measurements of properties of the formation and/or the borehole 12
downhole. In one embodiment, such measurements are of a movement of
components within the borehole, such as the velocity of a drill
bit. The velocity, in one embodiment, is related to the drill bit's
rate of penetration (ROP), which can be measured by various sensors
in the system 10. The system includes a sensor assembly having at
least one sensor configured to measure position and/or acceleration
of the drill bit or other component, and at least one circuit in
communication with the at least one sensor. The at least one
circuit is configured to a receive a signal from the sensor and
generate a signal representative of an instantaneous velocity of
the component.
[0013] In one embodiment, the system 10 includes a conventional
derrick 14 mounted on a derrick floor 16 that supports a mud motor
including a rotary table 18 that is rotated by a prime mover (not
shown) at a desired rotational speed. The drillstring 11 includes
one or more drill pipe sections 20 or coiled tubing that extend
downward into the borehole 12 from the rotary table 18, and is
connected to a drill bit assembly 22. Drilling fluid, or drilling
mud 24 may be pumped through the drillstring 11 and/or the borehole
12. The well drilling system 10 also includes a bottomhole assembly
(BHA) 26. The drill bit assembly 22 is powered by a surface rotary
drive, a motor using pressurized fluid (e.g., the mud motor), an
electrically driven motor and/or other suitable mechanism. In one
embodiment, the drillstring 11 is coupled to a drawworks 28 that is
operated to control drilling parameters such as the weight on bit
and the rate of penetration of the drillstring 11 (or components
therein such as the drill bit assembly 22) into the borehole
12.
[0014] During drilling operations a suitable drilling fluid 24
from, for example, a mud pit 30 is circulated under pressure
through the drillstring 11. The drilling fluid 24 passes into the
drillstring 11, and the drilling fluid 24 is discharged at a
borehole bottom 32 through an opening in a drill bit 34. The
drilling fluid 24 circulates uphole between the drill string 11 and
the borehole 12 and is discharged into the mud pit 30.
[0015] In one embodiment, the drilling assembly 22 is included in
the bottomhole assembly (BHA) 26, which is disposable within the
well logging system 10 at or near the downhole portion of the
drillstring 11. The BHA 26 includes any number of downhole tools 36
for various processes including formation drilling, geosteering,
and formation evaluation (FE) for measuring versus depth and/or
time in order to characterize one or more physical quantities in or
around a borehole.
[0016] The downhole tool 36, in one embodiment, includes at least
one sensor or sensor assembly 38 to estimate or measure the
velocity of one or more downhole components. The sensor assembly 38
or other components may also measure various mechanical, chemical
and/or physicochemical properties of the formation, downhole
components and/or the borehole 12. The data provided by the sensor
assembly 38 may be utilized to control and adjust environmental
and/or mechanical loads on the tool 36, the drill bit 34 and/or
other components of the drillstring 11. Various sensor assemblies
38 may be located at various locations on the drill string 11, such
as in the drill bit assembly 22, the downhole tool 36 or other
various downhole subs or modules.
[0017] The sensor assembly 38 includes or is in operable
communication with a circuit 40 that is configured to generate a
signal that is indicative of the instantaneous velocity and/or ROP
of a component. In one embodiment, the velocity is measured in one
or more of various directions, including an axial direction (i.e.,
parallel to a direction of the borehole 12 and/or a direction of a
gravitational field), a radial direction perpendicular to the axial
direction, and a tangential direction perpendicular to the radial
and axial directions. The sensor assembly 38 is thus capable of
estimating an instantaneous velocity of the component at a selected
time and/or the velocity of the component over a selected time
period. The circuit 40 may be connected to the sensor assembly 38
in a single housing or assembly, or may be located at a remote
location relative to the sensor assembly 38 such as a surface
location.
[0018] In one embodiment, the sensor assembly 38 includes one or
more sensors that are configured to generate a voltage signal that
is proportional to a position and/or instantaneous velocity of the
drill bit 34 or other component. In one embodiment, the one or more
sensors include at least one of an accelerometer and a position
sensor. The accelerometer includes components configured to
generate a voltage signal that is proportional in magnitude to the
change in instantaneous velocity of the moving component. The
position sensor is a strain gauge or any sensor configured to
generate a voltage signal that is proportional in magnitude to a
position of the component. In one example, the strain gauge
generates a voltage signal proportional to a strain on a component
of the drill string 11, where the strain is an indication of the
downhole position of the component.
[0019] The velocity/ROP signal may be obtained by integrating an
accelerometer signal or by differentiating a strain gauge signal
via the circuit 40, thus producing a resultant signal that is an
indicator of instantaneous velocity and/or ROP rather than an
indication of the change in bit ROP for a given period during a
drilling mode. The configuration of the circuit 40 is merely
exemplary, and may include additional elements as desired.
[0020] Referring to FIGS. 2 and 3A-B, in one embodiment, the
circuit 40 includes an integrator circuit 40 in communication with
an accelerometer that provides, in real time, an output signal that
is the time integral of the input signal from the accelerometer. In
one embodiment, as shown in FIG. 2, the circuit 40 is an active
integrator circuit. The active integrator circuit includes, for
example, an operational amplifier (op amp) 42. The active
integrator circuit includes a negative feedback 44 to the inverting
input 46 of the op amp 42, which ensures that the inverting input
will be held at zero Volts (0 V), i.e., act as a virtual ground.
The active integrator circuit also includes a resistor 48, and a
capacitor 50 across the negative feedback 44.
[0021] In this configuration, if the input voltage ("Vin") is
exactly 0 V, there will be no current through the resistor 48,
therefore no charging of the capacitor 50, and thus the output
voltage ("Vout") will not change. If the input voltage Vin from the
accelerometer is a constant, positive voltage, the op amp 42 output
Vout will fall negative at a linear rate, in an attempt to produce
the changing voltage across the capacitor 50 necessary to maintain
the current established by the voltage difference across the
resistor 48. Conversely, if the input voltage Vin is a constant
negative voltage, the resulting output voltage Vout is a linear,
rising (positive) voltage. The output voltage rate-of-change is
proportional to the value of the input voltage Vin. The output
voltage Vout is related to the input voltage Vin based on the
following equation:
v out t = - V in RC ##EQU00001## or ##EQU00001.2## V out = .intg. 0
1 - V in RC t + c , ##EQU00001.3##
where "R" is the resistance of the resistor 48, "C" is the
capacitance of the capacitor 50, and "c" is the output voltage at a
start time (t=0).
[0022] Referring to FIGS. 3A and 3B, in one embodiment, the circuit
40 includes a passive integrator circuit that includes a four
terminal circuit. As shown in FIG. 3A, the passive integrator
circuit may be a capacitive integrator including the resistor 48
and the capacitor 50. The passive integrator circuit outputs a
voltage signal proportional to the instantaneous velocity of the
component based on the following equation:
Y=X[Z.sub.C/(Z.sub.C+Z.sub.R)],
where "X" and "Y" are the input and output signals' amplitudes
respectively, and Z.sub.R and Z.sub.C are the impedances of the
resistor 48 and the capacitor 50 respectively. In an alternative
embodiment, shown in FIG. 3B, the passive integrator circuit is an
inductive integrator including the resistor 48 and an inductor
52.
[0023] Referring to FIGS. 4 and 5A-B, the circuit 40 is a
differentiator circuit in communication with a position sensor that
provides, in real time, an output signal that is the time
differential of the input signal from the position sensor. In one
embodiment, as shown in FIG. 4, the circuit 40 is an active
differentiator circuit including, for example, the op amp 42 and
the negative feedback 44 to the inverting input 46 of the op amp
42. The op amp 42 measures a change in voltage Vin by measuring
current through the capacitor 50 and outputs a voltage Vout
proportional to that current, thereby providing a voltage signal
indicative of the change in position (i.e., velocity) at a given
time. The right-hand side of the capacitor C is held to a voltage
of zero Volts (0V), due to the "virtual ground" effect. Thus, the
current "through" the capacitor is solely due to the change in the
input voltage Vin. A steady input voltage Vin does not result in an
output voltage Vout, but a changing input voltage Vin will result
in an output voltage Vout signal. The changing input voltage Vin
induces a current drop across the feedback resistor 48 which is the
same as the output voltage Vout. For example, a linear, positive
rate of Vin change results in a steady (i.e., constant) negative
Vout, and a linear negative rate of Vin change results in a steady
positive Vout. The faster the rate of Vin change (and corresponding
rate of position change or velocity), the greater the Vout
magnitude. The output voltage is related to the input voltage based
on the following equation:
V out = - RC v in t , ##EQU00002##
where "R" is the resistance of the resistor 48 and "C" is the
capacitance of the capacitor 50.
[0024] Referring to FIGS. 5A and 5B, in one embodiment, the circuit
40 is a passive differentiator circuit that includes a four
terminal circuit. The passive integrator circuit outputs a voltage
signal proportional the instantaneous velocity of the component
based on the following equation:
Y=X[Z.sub.C/(Z.sub.C+Z.sub.R)],
where "X" and "Y" are the input and output signals' amplitudes
respectfully, and Z.sub.R and Z.sub.C are the impedances of the
resistor 48 and the capacitor 50. In an alternative embodiment,
shown in FIG. 5B, the passive integrator circuit is an inductive
integrator including the resistor 48 and the inductor 52.
[0025] Each of the sensor assemblies 38 may include a single sensor
or multiple sensors located at a single location. In one
embodiment, the sensor assembly 38 includes one or more sensors
configured to measure velocity along selected directions, such as
the axial, radial and tangential directions. Furthermore, in other
embodiments, each sensor assembly 38 includes additional
components, such as clocks, memory processors, etc.
[0026] In one embodiment, the sensor assembly 38, downhole tool 36
and/or BHA 26 is equipped with transmission equipment to
communicate ultimately to a remote location such as a surface
processing unit 54. In one embodiment, the surface processing unit
54 is configured as a surface drilling control unit which controls
various drilling parameters such as rotary speed, weight-on-bit,
drilling fluid flow parameters and others. Such transmission
equipment may take any desired form, and different transmission
media and connections may be used. Examples of connections include
wired, fiber optic, wireless connections or mud pulse
telemetry.
[0027] In one embodiment, the surface processing unit 54, the
sensor assembly 38, downhole tool 36 and/or BHA 26 include
components as necessary to provide for storing and/or processing
data collected from the sensor assembly 38. Exemplary components
include, without limitation, at least one processor, storage,
memory, input devices, output devices and the like.
[0028] FIG. 3 illustrates a method 60 of estimating a velocity of a
downhole component. The method 60 includes one or more of stages
61-64 described herein. The method may be performed continuously or
intermittently as desired. The method is described herein in
conjunction with the sensor assemblies 38 and circuits 40, although
the method may be performed in conjunction with any number and
configuration of circuits, sensors and tools. The method may be
performed by one or more processors or other devices capable of
receiving and processing measurement data. In one embodiment, the
method includes the execution of all of stages 61-64 in the order
described. However, certain stages 61-64 may be omitted, stages may
be added, or the order of the stages changed.
[0029] In the first stage 61, the sensor assembly 38 is lowered
into a borehole, along with other components such as the drill bit
assembly 22 during, for example, a drilling and/or geosteering
operation.
[0030] In the second stage 62, the sensor assembly 38 generates a
voltage signal that is proportional in magnitude to an acceleration
or position of the sensor assembly 38. The sensor assembly 38
includes at least one of an accelerometer and a position sensor
such as a strain gauge.
[0031] In the third stage 63, the voltage signal is input into the
circuit 40, which generates an output voltage that is proportional
to an instantaneous velocity of the sensor assembly 38 at a
selected time and/or over a selected time period.
[0032] In the fourth stage 64, the output voltage signal is
transmitted to a user or processor to indicate the instantaneous
velocity of the sensor assembly 38 and the associated downhole
component. In one embodiment, data relating to the output voltage
signal and velocity measurement is stored in the sensor assembly 38
or another downhole component, and/or is transmitted to a processor
such as the surface processing unit 54, and can be retrieved
therefrom and/or displayed for analysis. As used herein, a "user"
may include a drillstring operator, a processing unit and/or any
other entity selected to retrieve the data and/or control the
drillstring 11.
[0033] Although the methods and systems described herein are
utilized to determine rotational velocity and/or ROP in a downhole
system, the methods and systems are not so limited and may be
utilized with any type of downhole or above-ground system that
would benefit from measurements of instantaneous velocity of a
component.
[0034] "Drillstring" or "string" as used herein, refers to any
structure or carrier suitable for lowering a tool through a
borehole or connecting a drill bit to the surface, and is not
limited to the structure and configuration described herein. For
example, the borehole string 11 is configured as a hydrocarbon
production string or formation evaluation string. The term
"carrier" as used herein means any device, device component,
combination of devices, media and/or member that may be used to
convey, house, support or otherwise facilitate the use of another
device, device component, combination of devices, media and/or
member. Exemplary non-limiting carriers include drill strings of
the coiled tube type, of the jointed pipe type and any combination
or portion thereof Other carrier examples include casing pipes,
wirelines, wireline sondes, slickline sondes, drop shots, downhole
subs, BHA's, drill string.
[0035] The systems and methods described herein provide various
advantages over prior art techniques. The systems and methods
herein reduce or minimize conversion errors, as compared with
conventional methods that require post processing of acceleration
and/or strain data, by including the integrator circuits with
accelerometers and/or differentiator circuits with position sensors
such as strain gauges. In addition, the systems and methods
described herein allow for ease of use, as velocity measurements
can be achieve through the inclusion of acceleration/position
sensors in existing modules, and also can be more simply produced
as contact with the actual borehole and/or drilling environment is
unnecessary.
[0036] In support of the teachings herein, various analyses and/or
analytical components may be used, including digital and/or analog
systems. The system may have components such as a processor,
storage media, memory, input, output, communications link (wired,
wireless, pulsed mud, optical or other), user interfaces, software
programs, signal processors (digital or analog) and other such
components (such as resistors, capacitors, inductors and others) to
provide for operation and analyses of the apparatus and methods
disclosed herein in any of several manners well-appreciated in the
art. It is considered that these teachings may be, but need not be,
implemented in conjunction with a set of computer executable
instructions stored on a computer readable medium, including memory
(ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives),
or any other type that when executed causes a computer to implement
the method of the present invention. These instructions may provide
for equipment operation, control, data collection and analysis and
other functions deemed relevant by a system designer, owner, user
or other such personnel, in addition to the functions described in
this disclosure.
[0037] Further, various other components may be included and called
upon for providing aspects of the teachings herein. For example, a
sample line, sample storage, sample chamber, sample exhaust, pump,
piston, power supply (e.g., at least one of a generator, a remote
supply and a battery), vacuum supply, pressure supply,
refrigeration (i.e., cooling) unit or supply, heating component,
motive force (such as a translational force, propulsional force or
a rotational force), magnet, electromagnet, sensor, electrode,
transmitter, receiver, transceiver, controller, optical unit,
electrical unit or electromechanical unit may be included in
support of the various aspects discussed herein or in support of
other functions beyond this disclosure.
[0038] One skilled in the art will recognize that the various
components or technologies may provide certain necessary or
beneficial functionality or features. Accordingly, these functions
and features as may be needed in support of the appended claims and
variations thereof, are recognized as being inherently included as
a part of the teachings herein and a part of the invention
disclosed.
[0039] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications will be
appreciated by those skilled in the art to adapt a particular
instrument, situation or material to the teachings of the invention
without departing from the essential scope thereof Therefore, it is
intended that the invention not be limited to the particular
embodiment disclosed as the best mode contemplated for carrying out
this invention, but that the invention will include all embodiments
falling within the scope of the appended claims.
* * * * *