U.S. patent application number 14/134040 was filed with the patent office on 2014-04-17 for system and method for acquiring information during underground drilling operations.
This patent application is currently assigned to APS Technology, Inc.. The applicant listed for this patent is APS Technology, Inc.. Invention is credited to Derek J. Barnes, Brent S. Hall.
Application Number | 20140102793 14/134040 |
Document ID | / |
Family ID | 37107845 |
Filed Date | 2014-04-17 |
United States Patent
Application |
20140102793 |
Kind Code |
A1 |
Hall; Brent S. ; et
al. |
April 17, 2014 |
SYSTEM AND METHOD FOR ACQUIRING INFORMATION DURING UNDERGROUND
DRILLING OPERATIONS
Abstract
A preferred method for acquiring information during an
underground drilling operation includes providing a sensing device
capable of acquiring information concerning the underground
drilling operation from a down-hole location on a selective basis
in response to an input from the surface, and drilling for a first
period of time. The preferred method also includes sending the
input to the sensing device after drilling for the first period of
time, and drilling during a second period of time while acquiring
the information using the sensing device.
Inventors: |
Hall; Brent S.; (Cheshire,
CT) ; Barnes; Derek J.; (Conroe, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
APS Technology, Inc. |
Wallingford |
CT |
US |
|
|
Assignee: |
APS Technology, Inc.
Wallingford
CT
|
Family ID: |
37107845 |
Appl. No.: |
14/134040 |
Filed: |
December 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12563007 |
Sep 18, 2009 |
8666908 |
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14134040 |
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11156002 |
Jun 17, 2005 |
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12563007 |
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Current U.S.
Class: |
175/40 |
Current CPC
Class: |
E21B 7/10 20130101; E21B
44/00 20130101; G06Q 30/0283 20130101; E21B 7/04 20130101; G06Q
30/04 20130101; E21B 47/24 20200501; E21B 47/022 20130101 |
Class at
Publication: |
175/40 |
International
Class: |
E21B 44/00 20060101
E21B044/00; E21B 7/04 20060101 E21B007/04 |
Claims
1. A method for forming a bore in an earth formation, comprising:
drilling on a straight-hole basis using a drill string comprising a
sensing device configured to generate tool-face readings on a
selective basis, and a telemetry system for transmitting the tool
face readings to the surface, so that the drill string advances in
to the earth formation, while the sensing device is in an inactive
mode in which the sensing device does not generate the tool-face
readings; performing a static survey to determine drift of the bore
after drilling on a straight-hole basis; and if the drift of the
bore exceeds a predetermined limit, drilling in the earth formation
on a directional basis using the drill string, while the sensing
device is in an active mode in which the sensing device generates
the tool-face readings.
2. The method of claim 1, wherein drilling in the earth formation
on a directional basis using the drill string, while the sensing
device is in an active mode in which the sensing device generates
the tool-face readings further comprises drilling on a directional
basis while the telemetry system is in an active mode in which the
telemetry system transmits the tool face readings to the
surface.
3. The method of claim 1, wherein drilling on a straight-hole
basis, while the sensing device is in an inactive mode in which the
sensing device does not generate the tool-face readings further
comprises drilling on a straight-hole basis while the telemetry
system is in an inactive mode in which the telemetry system does
not transmit the tool face readings to the surface.
4. The method of claim 1, further comprising resuming drilling on a
straight-hole basis if the drift of the bore is within the
predetermined limit.
5. The method of claim 1, wherein drilling in the earth formation
on a directional basis using the drill string comprises drilling to
return the drift of the bore to within the predetermined limit.
6. The method of claim 1, wherein performing a static survey to
determine drift of the bore after drilling on a straight-hole basis
comprises performing a static survey to measure inclination and
azimuth of the bore.
7. The method of claim 2, wherein drilling in the earth formation
on a directional basis using the drill string, while the sensing
device is in an active mode in which the sensing device generates
the tool-face readings comprises transmitting the tool face
readings to the surface using mud-pulse telemetry.
8. The method of claim 6, wherein performing a static survey to
measure inclination and azimuth of the bore comprises measuring the
inclination of the bore using at least one accelerometer of the
sensing device, and measuring the azimuth of the bore using at
least one magnetometer of the sensing device.
9. The method of claim 1, further comprising recording information
concerning the static survey.
10. The method of claim 9, wherein the information concerning the
static survey comprises information required for certification of
the static survey.
11. The method of claim 1, wherein drilling on a straight-hole
basis comprises drilling vertically.
12. The method of claim 1, further comprising activating the
sensing device to begin generating the tool-face readings by
interrupting a flow of drilling mud within the bore for a
predetermined time period.
13. The method of claim 12, wherein the predetermined amount of
time is less than the amount of time required by the sensing device
to generate and store information relating to the static
survey.
14. The method of claim 1, further comprising transmitting
information associated with the static survey to the surface.
15. The method of claim 14, further comprising determining whether
the drift of the bore exceeds the predetermined limit based on the
information associated with the static survey to the surface.
16. A method for acquiring information during an underground
drilling operation, comprising: providing a sensing device capable
of acquiring information concerning the underground drilling
operation from a down-hole location on a selective basis in
response to an input from the surface; drilling for a first period
of time; sending the input to the sensing device after drilling for
the first period of time; and drilling for a second period of time
while acquiring the information using the sensing device.
17. The method of claim 16, further comprising performing a first
type of the underground drilling operation during the first period
of time, and performing a second type of the underground drilling
operation during the second period of time.
18. The method of claim 17, wherein drilling during a second period
of time while acquiring the information using the sensing device
comprises drilling during the second period of time while acquiring
information required to perform the second type of the underground
drilling operation using the sensing device.
19. The method of claim 16, further comprising generating the input
by stopping a flow of drilling mud associated with the underground
drilling operation for a predetermined amount of time.
20. The method of claim 19, wherein the predetermined period of
time is less than an amount of time required by the sensing device
to generate and store static survey information.
21. The method of claim 16, wherein drilling during a second period
of time while acquiring the information using the sensing device
comprises drilling during the second period of time while acquiring
tool face readings.
22. The method of claim 17, wherein the first type of the
underground drilling operation is vertical drilling, and the second
type of the underground drilling operation is directional
drilling.
23. The method of claim 16, further comprising transmitting the
information to the surface using mud-pulse telemetry.
24. A method for allocating costs associated with the use of a
system capable of generating and transmitting information
concerning an underground drilling operation on a selective basis,
the method comprising: providing the system to a user; and charging
a usage rate based on an amount of the information acquired by the
sensing device during the underground drilling operation.
25. The method of claim 24, wherein charging a usage rate based on
an amount of the information acquired by the sensing device during
the underground drilling operation comprises charging a first usage
rate based on an amount of a first type of information acquired by
the sensing device during a first type of underground drilling
operation, and charging a second usage rate based on an amount of a
second type of information acquired by the sensing device during a
second type of underground drilling operation.
26. The method of claim 24, wherein the first type of information
comprises tool face readings, and the second type of information
comprises static survey data.
27. The method of claim 26, wherein the first type of underground
drilling operation comprises directional drilling, and the second
type of underground drilling operation comprises vertical
drilling.
28. A system for providing information during an underground
drilling operation, comprising: a sensing device comprising a
sensor, and a signal processor communicatively coupled to the
sensor, the sensing device generating static survey information
concerning the underground drilling operation in response to a
first predetermined criterion, and the sensing device generating
tool face readings concerning the underground drilling operation on
a substantially continuous basis in response to a second
predetermined criterion; and a telemetry system communicatively
coupled to the sensing device for transmitting the static survey
information and the tool face readings to the surface.
29. The system of claim 28, wherein the sensor comprises a
magnetometer and an accelerometer.
30. The system of claim 28, wherein the first predetermined
criterion comprises commencing drilling.
31. The system of claim 28, wherein the second predetermined
criterion comprises absence of the static survey information in a
memory-storage device of the direction measurement unit upon
commencing drilling.
32. The system of claim 28, wherein the telemetry system comprises
a pulser for generating pressure pulses in drilling mud associated
with the drilling operation, an encoder communicatively coupled to
the pulser for encoding information in the pulses, a transducer to
sending the pressure pulses, and a decoder communicatively coupled
to the transducer for decoding the information encoded in the
pressure pulses.
33. The system of claim 28, further comprising a pressure barrel
for housing the sensing device and an encoder of the telemetry
system.
34. The system of claim 28, further comprising an output module
communicatively coupled to the telemetry system for at least one of
displaying, storing, and transmitting the static survey information
and the tool face readings.
35. The system of claim 28, further comprising a switching device
communicatively coupled to the sensing device for sensing flow of
drilling mud associated with the underground drilling
operation.
36. The system of claim 28, wherein the sensing device stores the
static survey information and causes the telemetry system to
transmit the static survey information to the surface upon
commencement of drilling.
37. A system for providing information during an underground
drilling operation that forms a subsurface bore, comprising: a
sensing device capable of generating information at a location
within the bore; a telemetry system communicatively coupled to the
sensing device for transmitting the information from the sensing
device the surface; and an output device communicatively coupled to
the telemetry system for at least one of recording and displaying
the information at a location on the surface, wherein at least one
of the sensing device, the telemetry system, and the output device
are configured to facilitate access to the information only upon at
least one of entry of a password and insertion of a dongle.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 12/563, 007 filed Sep. 18, 2009, which is a continuation
of U.S. patent application Ser. No. 11/156,002 filed Jun. 17, 2005,
now abandoned, the entire contents of which are incorporated herein
by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to underground drilling. More
specifically, the invention relates to a system and method for
acquiring information, such as directional guidance information,
during underground drilling operations.
BACKGROUND OF THE INVENTION
[0003] Underground drilling, such as gas, oil, or geothermal
drilling, generally involves drilling a bore through a formation
deep in the earth. Such bores are formed by connecting a drill bit
to long sections of pipe, referred to as "drill pipe," so as to
form an assembly commonly referred to as a "drill string." The
drill string extends from the surface to the bottom of the
bore.
[0004] The drill bit is rotated so that the drill bit advances into
the earth, thereby forming the bore. In a drilling technique
commonly referred to as rotary drilling, the drill bit is rotated
by rotating the drill string at the surface. In other words, the
torque required to rotate the drill bit is generated above-ground,
and is transferred to the drill bit by way of the drill string.
[0005] Alternatively, the drill bit can be rotated by a drilling
motor. The drilling motor is usually mounted in the drill string
proximate the drill bit. The drill bit can be rotated by the
drilling motor alone, or by rotating the drill string while
operating the drilling motor.
[0006] One type of drilling motor known as a "mud motor" is powered
by drilling mud. Drilling mud is a fluid that is pumped under high
pressure from the surface, through an internal passage in the drill
string, and out through the drill bit. The drilling mud lubricates
the drill bit, and flushes cuttings from the path of the drill bit.
The drilling mud then flows to the surface through an annular
passage formed between the drill string and the surface of the
bore.
[0007] In a drill string equipped with a mud motor, the drilling
mud is routed through the drilling motor. The mud motor is equipped
with a rotor that generates a torque in response to the passage of
the drilling mud therethrough. The rotor is coupled to the drill
bit so that the torque is transferred to the drill bit, causing the
drill bit to rotate.
[0008] Drilling operations can be conducted on a vertical,
horizontal, or directional basis. Vertical drilling refers to
drilling in which the trajectory of the drill-string is inclined
approximately 10.degree. or less in relation to the vertical.
Horizontal drilling refers to drilling in which the drill-string
trajectory is inclined approximately 90.degree.. Directional
drilling refers to drilling in which the trajectory of the
drill-string is inclined between approximately 10.degree. and
approximately 90.degree..
[0009] Various systems and techniques can be used to perform
directional and horizontal drilling. For example, so-called
steerable systems use a drilling motor with a bent housing. A
steerable system can be operated in a sliding mode in which the
drill string is not rotated, and the drill bit is rotated
exclusively by the drilling motor. The bent housing steers the
drill bit in the desired direction as the drill string slides
through the bore, thereby effectuating directional drilling.
Alternatively, the steerable system can be operated in a rotating
mode in which the drill string is rotated while the drilling motor
is running. This technique results in a substantially straight
bore.
[0010] So-called rotary steerable tools can also be used to perform
directional drilling. One particular type of rotary steerable tool
can include pads located on the drill string, proximate the drill
bit. The pads can extend and retract with each revolution of the
drill string. Alternatively, in a system that uses a non-rotating
sleeve, the pads can remain fixed so that the pads exert a
continuous side force. The contact the between the pads and the
surface of the drill hole exerts a lateral force on the string.
This force pushes or points the drill bit in the desired direction
of drilling. A substantially straight bore is drilled when the pads
remain in their retracted positions.
[0011] All wells typically require monitoring to determine the
trajectory of the drill bit through the earth. Such monitoring
typically utilizes the measurements of the bore's inclination,
sometimes referred to as drift, which is the angle of the bore
measured from vertical and the direction or azimuth of any such
inclination measured from true north.
[0012] In addition, when drilling in "sliding mode," i.e., while
the drill string is not rotating, directional and horizontal
drilling require real-time knowledge of the angular orientation of
a fixed reference point on the circumference of the drill string in
relation to a reference point on the bore. The reference point is
typically magnetic north in a vertical well, or the high side of
the bore in an inclined well. This orientation of the fixed
reference point is typically referred to as "tool face," or "tool
face angle."
[0013] Drill strings used for directional and horizontal drilling
typically are equipped with a measurement while drilling (MWD) tool
to provide tool face readings. The MWD tool is usually mounted in
the bottom-hole assembly of the drill string. The MWD tool can
include sensors for providing the measurements needed to determine
tool face. An MWD tool typically includes three accelerometers
mounted on orthogonal axes, whose readings may be used to determine
inclination and tool face, and a triaxial magnetometer whose
readings, in conjunction with those of the accelerometers, may be
used to determine the azimuth heading. The MWD tool can also
include a signal processor programmed to calculate tool face based
on the noted measurements.
[0014] These orientation readings generated by the MWD tool need to
be transmitted to the surface on a real-time basis for
interpretation and analysis. Such data transmission is usually
accomplished using a technique referred to as "mud-pulse
telemetry." In a typical mud-pulse telemetry system, electrical
signals representing directional or other information are received
and digitally encoded by a microprocessor-based encoder located in
the MWD tool.
[0015] The output of the encoder can be transmitted to an
electrically-powered pulser. The pulser forms part of the bottom
hole assembly, and generates pressure pulses in the drilling mud in
response to the output of the encoder. The pulser can generate the
pulses by intermittently restricting the flow area of the drilling
mud so as to back pressure the column of drilling mud located
up-hole thereof.
[0016] The digitally-encoded information generated by the encoder
is incorporated into the pulses. The pulses can be defined by a
variety of characteristics, including amplitude (the difference
between the maximum and minimum values of the pressure), duration
(the time interval during which the pressure is increased), shape,
and frequency (the number of pulses per unit time or, conversely,
the time between pulses).
[0017] Various encoding systems have been developed using one or
more pressure pulse characteristics to represent binary data, i.e.,
the binary digits 1 or 0. For example, a pulse of 0.5 second
duration can be designated as representing the binary digit 1. A
pulse of 1.0-second duration can be designated as representing the
binary digit 0. Other examples can include hexadecimal encoding
that uses similar techniques of pulse placement, but assigns
different values to the detected positions of the generated
pulses.
[0018] The pulses travel up the column of drilling mud flowing down
to the drill bit, and are sensed by a pressure transducer located
at or near the surface. The data from the pressure transducer is
then decoded and analyzed electronically by the surface receiver,
and the resulting information can be analyzed by the personnel
operating the drilling rig, or other users.
[0019] Encoded data can be sent down-hole from the surface. One
type of encoding system utilizes pressure by pulsing the drilling
mud at or near the surface. A pressure transducer can be installed
in the MWD tool to sense the pressure pulses. The encoder of the
MWD tool can be programmed to decide the output signal of pressure
transducer. Guidance information can thus be sent from the surface
to the steering means to guide the drill bit in a desired
direction. Other communication techniques can use rotation, applied
weight, acoustic pulses, and electromagnetic carrier waves. These
types of techniques are typically multi event and complex.
[0020] As the MWD tool and the pulser are operated on a
substantially continuous basis during directional or horizontal
drilling operations, a substantial amount of electrical power can
be required during such operations. Electrical power can be
supplied by batteries located in the down-hole assembly. In such
applications, the power requirements of the MWD tool and (more so)
the pulser, can drain the batteries, thereby necessitating a
time-consuming removal of the drill string so that the batteries
can be replaced.
[0021] Alternatively, the drill string can be equipped with a
device such as a turbine-driven alternator to power the MWD tool
(and the other electrical components of bottom-hole assembly).
[0022] A typical MWD tool is relatively complex and expensive.
Moreover, interpretation and analysis of the directional
information provided by the MWD tool is usually performed by an
engineer or technician with specialized training (rather than the
drill-rig operators), due to the relative complexity of these
tasks.
[0023] Determining tool face on a continuous basis, in general, is
not required during vertical drilling. Directional information
associated with vertical drilling may be obtained as needed by
performing a static survey when rotation of the drill string is
interrupted to add another section of drill pipe. A static survey
could be conducted, for example, by lowering a compass, a plumb
line, and a camera through the drill string, and photographing the
compass and plumb line when the compass and plumb line reach the
bottom of the drill string.
[0024] The directional information obtained during the static
survey is used to determine whether the trajectory of the bore has
deviated from the vertical direction and, if so, the extent and
direction of the deviation. Deviation beyond a predetermined
amount, e.g., 5.degree., may necessitate corrective action to
return the trajectory of the bore to within the limits of what is
considered "vertical."
[0025] This corrective action may necessitate removing the drill
string from the bore, and configuring the drill string for
directional drilling. For example, the down-hole assembly can be
configured with a steerable drilling assembly comprising a mud
motor or other suitable device for steering the drill bit. An MWD
tool with mud-pulse telemetry equipment can also be added to the
bottom-hole assembly to generate and transmit the tool-face angle
data required for directional drilling. The effort required to
remove and reconfigure the drill string can be substantial, and can
adversely affect the schedule of drilling operations. Moreover,
specially-trained engineers or technicians need to be brought on
site to install the MWD tool, and to interpret and analyze the
directional data from the MWD tool, which can further increase the
costs and scheduling impact associated with correcting the
deviation in the bore.
[0026] Static surveys may also be required by various regulatory
authorities, to verify that a well remains within predetermined
geographic boundaries. Static surveys acquired for this purpose
must usually be overseen by a qualified surveyor located on-site as
the survey is conducted. The term "qualified surveyor," as used
herein, refers to a surveyor who is qualified, certified, or
otherwise approved by the governing regulatory authority to oversee
the static survey.
[0027] If deviation data has been obtained during normal drilling
operations, without a qualified surveyor in attendance, owners of
the mineral rights and/or the regulatory authorities may require
that the bottom hole location be verified and certified by a
separate survey device operated by a qualified surveyor. This can
involve substantial costs resulting from additional expenditures of
time, and additional service fees. Therefore, the need for on-site
oversight can potentially delay, and thereby increase the expense
of, the drilling operation.
SUMMARY OF THE INVENTION
[0028] A preferred method for forming a bore in an earth formation
comprises drilling on a straight-hole basis using a drill string
comprising a sensing device configured to generate tool-face
readings on a selective basis, and a telemetry system for
transmitting the tool face readings to the surface, so that the
drill string advances in to the earth formation, while the sensing
device is in an inactive mode in which the sensing device does not
generate the tool-face readings.
[0029] The method also comprises performing a static survey to
determine drift of the bore after drilling on a straight-hole basis
and, if the drift of the bore exceeds a predetermined limit,
drilling in the earth formation on a directional basis using the
drill string, while the sensing device is in an active mode in
which the sensing device generates the tool-face readings.
[0030] A preferred method for acquiring information during an
underground drilling operation comprises providing a sensing device
capable of acquiring information concerning the underground
drilling operation from a down-hole location on a selective basis
in response to an input from the surface, and drilling for a first
period of time. The preferred method also comprises sending the
input to the sensing device after drilling for the first period of
time, and drilling for a second period of time while acquiring the
information using the sensing device.
[0031] A preferred method is provided for allocating costs
associated with the use of a system capable of generating and
transmitting information concerning an underground drilling
operation on a selective basis. The preferred method comprises
providing the system to a user, and charging a usage rate based on
an amount of the information acquired by the sensing device during
the underground drilling operation.
[0032] A preferred embodiment of a system for providing information
during an underground drilling operation comprises a sensing device
comprising a sensor, and a signal processor communicatively coupled
to the sensor. The sensing device generates static survey
information concerning the underground drilling operation in
response to a first predetermined criterion. The sensing device
generates tool face readings concerning the underground drilling
operation on a substantially continuous basis in response to a
second predetermined criterion.
[0033] The system also comprises a telemetry system communicatively
coupled to the sensing device for transmitting the static survey
information and the tool face readings to the surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The foregoing summary, as well as the following detailed
description of a preferred embodiment, are better understood when
read in conjunction with the appended diagrammatic drawings. For
the purpose of illustrating the invention, the drawings show an
embodiment that is presently preferred. The invention is not
limited, however, to the specific instrumentalities disclosed in
the drawings. In the drawings:
[0035] FIG. 1 is a side view of a drill string incorporating a
preferred embodiment of a system for acquiring information during
underground drilling operations, depicting the drill string within
a bore formed in an earth formation by the drill string;
[0036] FIG. 2 is another side view of the drill string shown in
FIG. 1, showing additional detail of the drill string;
[0037] FIG. 3 is a magnified view of the area designated "A" in
FIG. 2, depicting a drill collar of the drill string in
longitudinal cross-section;
[0038] FIG. 4 is a cross-sectional view taken through the line
"B-B" of FIG. 3;
[0039] FIG. 5 is a block diagram depicting the system shown in
FIGS. 1-4;
[0040] FIG. 6 is a block diagram depicting a direction measurement
unit of the system shown in FIGS. 1-5; and
[0041] FIG. 7 is a flow diagram depicting a preferred embodiment of
a method than can be performed using the system shown in FIGS.
1-6.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0042] The figures depict a preferred method, and a preferred
embodiment of a system 10 for acquiring information during
underground drilling operations. The system 10 comprises a sensing
device in the form of a direction measurement unit 12, a telemetry
system 14, and a display module 18. The system 10, as discussed
below, can be used to conduct static surveys required during
vertical drilling to verify that the drift of the bore formed by
the drilling operation is within predetermined limits. The system
10 can also acquire tool face readings on a selective, as-needed
basis.
[0043] The system 10 can be used as part of a drill string 100 (see
FIGS. 1 and 2). The drill string 100 is formed from interconnected
sections of drill pipe 101, and a bottom hole assembly 102. The
bottom hole assembly 102 comprises a drill bit 104, and a drill
collar 106. The drill collar 106 couples the drill bit 104 and the
lowermost section of drill pipe 101, and weights the drill bit 104
to improve the performance thereof.
[0044] The drill string 100 is rotated by a motor 107 of a drilling
rig 108 located on the surface, as shown in FIG. 1. Drilling torque
can be transmitted from the motor 107 to the drill string 100
through a turntable 109, and a kelly (not shown). Drilling torque
is transmitted to the drill bit 104 by way of the drill pipe 101
and the drill collar 106. The rotating drill bit 104 advances into
an earth formation 110, thereby forming a bore 112.
[0045] Drilling mud 114 is pumped from the surface, through the
sections of drill pipe 101 and the drill collar 106, and out of the
drill bit 104. The drilling mud 114 is circulated by a pump 116
located on the surface. The drilling mud 114, upon exiting the
drill bit 104, returns to the surface by way of an annular passage
formed between the section of drill pipe 101 and the surface of the
bore 112, as depicted in FIG. 2.
[0046] The bottom-hole assembly 102 preferably is configured for
directional drilling. For example, the bottom hole assembly 102 can
include a rotary steerable tool 118 located between the drill
collar 106 and the drill bit 104. The rotary steerable tool 118
includes pads that extend and retract with each revolution of the
drill string 100. Contact between the pads and the surface of the
bore 112 exerts a lateral force on the drill string 100. This force
pushes or points the drill bit 104 in the desired direction of
drilling. The bore 112 is drilled in a substantially straight
direction when the pads remain in their retracted positions.
[0047] The use of the rotary steerable tool 118 to perform
directional drilling is specified for exemplary purposes only. The
drill string 100 can be equipped with other means for performing
directional drilling, such as a drilling motor with a bent housing.
Alternatively, the drill string 100 can be equipped with a rotary
steerable motor as described in U.S. application Ser. No.
11/117,802, filed Apr. 29, 2005, the contents of which is
incorporated by reference herein in its entirety.
[0048] The direction measurement unit 12 can be housed within a
pressure barrel 19. The pressure barrel 19 can be suspended within
the drill collar 106, up-hole of the drill bit 104, as shown in
FIG. 3. The pressure barrel 19 preferably is formed from beryllium
copper or non-magnetic, high-strength stainless steel.
[0049] The direction measurement unit 12 can include three
magnetometers 20 for measuring azimuth about three orthogonal axes,
and three accelerometers 22 for measuring inclination about the
three orthogonal axes (see FIG. 6). The direction measurement unit
12 can also include a signal processor 16 communicatively coupled
to each of the magnetometers 20 and accelerometers 22.
[0050] The signal processor 16 can comprise a processor such as a
microprocessor 28, and a memory storage device 30 communicatively
coupled to the microprocessor 28. The direction measurement unit 12
can also include a set of computer-executable instructions 32
stored on the memory storage device 30. The signal processor 16 can
be packaged as a board mounted within the pressure barrel 19. The
signal processor 16 can be isolated from shock and vibration by a
suspension or other suitable means.
[0051] The signal processor 16 can be programmed to calculate the
azimuth and inclination of the bore 112 based on the readings of
the magnetometers 20 and accelerometers 22, respectively, using
conventional techniques known to those skilled in the art of
underground drilling. As discussed below, static surveys can be
conducted at predetermined intervals to determine azimuth and
inclination. The resulting data can be transmitted to the surface
for analysis using the telemetry system 14.
[0052] The signal processor 16 can also be programmed to calculate
the tool face of the drill bit 104 based on the readings of the
magnetometers 20 and accelerometers 22, using conventional
techniques known to those skilled in the art of underground
drilling. Alternatively, tool face can be calculated based on the
techniques described in U.S. provisional application No.
60/676,072, filed Apr. 29, 2005, the contents of which is
incorporated by reference herein in its entirety.
[0053] The direction measurement unit 12 generates a digital output
representative of the inclination, azimuth, and tool face readings.
For example, the direction measurement unit 12 can generate a
digital output in the form of four-bit "nybbles," where each nybble
represents a hexadecimal digit. Other digital formats can be used
for the output of the direction measurement unit 12, in the
alternative.
[0054] The drill string 100 can be used to drill directionally if
the drift of the bore 112, as determined from the static survey,
exceeds a predetermined criterion, e.g., greater than 5.degree..
inclination. A particular criterion for the acceptable amount of
drift is specified for exemplary purposes only. The acceptable
amount of drift is application-dependent, and is often expressed as
a function of both inclination and azimuth.
[0055] The drill bit 104 can be guided from the surface to alter
the direction of the bore 112, so as to place the drift of the bore
112 within limits. As discussed below, the system 10 can calculate
and transmit tool face readings during directional drilling, to
provide the directional guidance required for such drilling.
[0056] The telemetry system 14 preferably transmits data from the
bottom-hole assembly 102 to the surface using mud-pulse telemetry.
The telemetry system 14 can include an encoder 36, a decoder 38, a
pulser 40, and a pressure transducer 42 (see FIGS. 3-5).
[0057] The encoder 36 can be packaged as a board mounted within the
pressure barrel 19. The encoder 36 can be isolated from shock and
vibration by a suspension or other suitable means. The encoder 36
is communicatively coupled to the sensor board 16 of the direction
measurement unit 12, as shown in FIG. 5. The encoder 36 receives
the digitized output of the direction measurement unit 12
representative of the inclination, azimuth, and tool face readings
generated by the direction measurement unit 12.
[0058] The encoder 36 can comprise a processor such as a
microprocessor 50, and a memory storage device 52 communicatively
coupled to the microprocessor 50. The encoder 36 can also include a
set of computer-executable instructions 54 stored on the memory
storage device 52.
[0059] The pulser 40 is communicatively coupled to the encoder 36.
The pulser 40 is suspended within the drill collar 106, up-hole of
the pressure barrel 19. The pulser 40 generates pressure pulses in
the column of drilling mud 114 being pumped down-hole through the
drill collar 106, in response to inputs from the encoder 36. In
particular, the encoder 36 processes the digitized inclination,
azimuth, or tool face information received from the direction
measurement unit 12. The encoder 36 encodes the information as a
series of pressure pulses in the drilling mud 114 by issuing
commands to the pulser 40. The information can be encoded in the
pulses (and subsequently decoded) based on the amplitude, width, or
time separation of the pulses, using techniques known to those
skilled in the art of underground drilling.
[0060] Each pulse preferably has a predetermined duration and
amplitude that makes the pulse suitable for detection by the
pressure transducer 42. For example, each pulse can have a duration
of approximately 1.5 seconds, and an amplitude of approximately ten
to approximately one-hundred pounds per square inch. Specific
values for the duration and amplitude of the pulses are provided
for exemplary purposes only. Other values for each of these
parameters can be used in alternative embodiments.
[0061] The pulser 40 can include a stator 88 that forms passages 90
through which the drilling mud 114 flows (see FIG. 3). The pulser
40 also can include a rotor 92 positioned upstream or downstream of
the stator 88. The rotor 92 can be rotated continuously by the
drilling mud 114. (This type of pulser is commonly referred to as a
mud siren.)
[0062] The rotor 92 can be rotated incrementally, in the
alternative. The incremental movement can be achieved by
oscillating the rotor 92, or by incrementally rotating the rotor 92
in one direction. The movement of the rotor 92 in relation to the
stator 88 causes the blades of the rotor 92 to alternatively
increase and decrease the degree to which the blades obstruct the
stator passages 90, thereby generating pulses in the drilling mud
114. Preferably, the pulser 40 can be converted between a
fixed-mount and a retrievable configuration, to provide the user
with flexibility in choosing either mounting configuration. A
suitable pulser 40 can be obtained, for example, from APS
Technology, Inc. of Cromwell, Conn. Pulsers suitable for use as
part of the telemetry system 14 are described in U.S. Pat. No.
6,714,138 (Turner et al.), and U.S. application Ser. No.
10/888,312, filed Jul. 9, 2004. Each of these documents is
incorporated by reference herein in its entirety.
[0063] Other means for generating pressure pulses include opening
and closing a poppet valve, or opening a valve that permits some of
the drilling mud to port from the center bore to the annulus
between the drill collar and the well bore wall (thus generating a
negative pressure pulse). Either of these means can be used in lieu
of the pulser 40 in alternative embodiments. Moreover, the signal
can be transmitted using acoustic or electromagnetic transmission
techniques, either in discrete pulses or as part of a carrier wave,
in other alternative embodiments.
[0064] The pressure transducer 42 preferably is a strain-gauge
pressure transducer. The pressure transducer 42 is located within
the column of drilling mud 114, proximate the surface (see FIG. 2).
The pulses generated in the drilling mud 114 by the pulser 40
propagate up-hole through the drill string 100, and are sensed by
the pressure transducer 42. The pressure transducer 42 generates an
electrical output representative of the amplitude and duration of
the pulses.
[0065] The decoder 38 is located on the surface, and can be
configured as a stand-alone unit. The decoder 38 is communicatively
coupled to the pressure transducer 42. The decoder 38 can include a
processor such as a microprocessor 58, and a memory storage device
60 communicatively coupled to the microprocessor 58 (see FIG. 5).
The decoder 38 can also include a set of computer-executable
instructions 62 stored on the memory storage device 60.
[0066] The decoder 38 is configured to decode the directional
guidance information encoded in the pressure pulses. The decoder 38
thus places the information in a format suitable for analysis by
the end user of the information, e.g., the drill rig operators,
on-site technicians or engineers, etc.
[0067] The telemetry system 14 is configured to transmit data in
the up-hole direction only. Alternative embodiments of the system
10 can include telemetry systems capable of transmitting in the
both up-hole and down-hole directions.
[0068] The decoder 38 is communicatively coupled to the display
module 18. The display module 18 can include one or more output
devices configured to display, store, transmit, or otherwise
process the output from the decoder 38. For example, the display
module 18 can include a strip chart recorder 66 to provide a basic
readout of the information output by the decoder 38.
[0069] In applications where greater data processing capability is
required or desired, the display module 18 can include can include
a computing device 68, such as a personal computer, that
facilitates processing and monitoring of the information on-site,
on a real-time basis. Alternatively, the output of the decoder 38
can be transmitted for monitoring or storage off-site. Data
transmission can be accomplished by any suitable means, such as
wireless transmission, the internet, an intranet, etc.
[0070] The computing device 68 can also be programmed to store the
information output by the decoder 38, so that the information can
be accessed and analyzed at a later time.
[0071] The system 10 can also include a switching device 70 that
senses whether drilling mud 114 is being pumped through the drill
string 100 (see FIGS. 3 and 5). The switching device 70 is
communicatively coupled to the direction measurement unit 12. A
suitable switching device 70 can be obtained from APS Technology,
Inc. as the FlowStat.TM. Electronically Activated Flow Switch.
[0072] The system 10 can further comprise one or more batteries 72
for powering the pulser 40, encoder 36, and direction measurement
unit 12 (see FIG. 3). Alternatively, power can be supplied by a
turbine-alternator assembly or other suitable power source.
[0073] The battery 72 and the switching device 70 can be suspended
within the drill collar 106, down hole of the pulser 40 and the
pressure barrel 19.
[0074] The system 10, as noted previously, can provide directional
guidance information during vertical drilling operations in the
form of static survey data. The system 10 can also provide tool
face readings on a substantially continuous basis. The system 10
can thus facilitate directional drilling to correct unacceptable
drift in the bore 112, without a need to raise the drill string 100
to the surface to reconfigure the drill string 100 for directional
drilling.
[0075] For example, vertical drilling can commence while the
direction measurement unit 12 and the telemetry system 14
(including the pulser 40) are inactive, i.e., while the direction
measurement unit 12 and the telemetry system 14 are not generating
and transmitting azimuth, inclination, or tool face readings (see
FIG. 7).
[0076] A static survey can be conducted after vertical drilling has
progressed, in response to a predetermined criterion. For example,
the direction measurement unit 12 can be programmed to initiate a
static survey each time drilling is stopped, as indicated by the
interruption in the flow of drilling mud 114 as sensed by the flow
switch 70. (During normal operations, drilling will be stopped each
time an additional section of drill pipe 101 is added to the drill
string 100.)
[0077] The direction measurement unit 12 commences a static survey
by acquiring data from the magnetometers 20 and the accelerometers
22, and storing the data in registers within the memory-storage
device 30. The direction measurement unit 12 then calculates
azimuth and inclination of the bore 112 based on the data, and
stores the resulting azimuth and inclination readings in additional
registers in the memory-storage device 30. The direction
measurement unit 12 can transmit the azimuth and inclination
readings to the encoder 36 when drilling resumes following addition
of the new section of drill pipe 101, as indicated by resumption in
the flow of drilling mud as sensed by the switching device 70. The
registers within the memory-storage device 30 that hold the azimuth
and inclination readings, and the associated data from the
magnetometers 20 and accelerometers 22, can be zeroed upon
transmission of the azimuth and inclination readings to the encoder
36.
[0078] The encoder 36 and the pulser 40 transmit the azimuth and
inclination readings to the surface by way of pressure pulses
produced in the drilling mud 114, as discussed above. The pressure
pulses can be sensed by the pressure transducer 42, and decoded by
the decoder 38.
[0079] The decoded azimuth and inclination readings can be
displayed by the display module 18 in a suitable format, e.g., on a
video screen of the computing device 68, by a printout generated by
the strip-chart printer 66, etc.
[0080] The azimuth and inclination readings can be stored, for
example, on the computing device 68. Each set of readings can be
stored with other information relating to the readings, such as the
time the readings were acquired, the drilling depth at the time of
acquisition, etc., so that the static survey can be certified at a
later time (provided that an acceptable chain of custody is
established for the stored information). This practice can
eliminate the need for on-site monitoring of the static survey by a
qualified surveyor. The costs of such monitoring, and the potential
delays associated with additional monitoring through the use of
other devices upon completion of the well, or sections thereof, can
thereby be substantially reduced or eliminated.
[0081] The static survey data can also be stored, for example, in
the memory storage devices 30, 52, 60 of the of the respective
direction measurement unit 12, encoder 36, or decoder 38, for
retrieval and analysis upon the conclusion of the drilling
operations.
[0082] The drill rig operators can assess whether the drift of the
bore 112 is within a predetermined limit, e.g., less than 5.degree.
inclination, based on the azimuth and inclination readings.
Vertical drilling can continue, if the drift of the bore 112 is
within limits.
[0083] Drilling can be interrupted if the azimuth and inclination
readings indicate that the drift of the bore 112 is greater than
the predetermined limit. Corrective action in the form of
directional drilling can subsequently be undertaken, to return the
drift of the bore 112 to within acceptable limits.
[0084] If necessary, technicians or engineers qualified to oversee
directional drilling can be brought on site once the need for
directional drilling is identified. The drill string 100 preferably
is equipped with the rotary steerable tool 118 or other suitable
device for steering the drill bit 104, a discussed above.
[0085] The system 10 can provide the tool face readings required to
guide the drill bit 104 during directional drilling. The direction
measurement unit 12 and the telemetry system 14 can be made active
during directional drilling. The direction measurement unit 12 then
generates tool face readings on a continuous basis, and the
telemetry system 14 continually transmits the tool face readings to
the surface via pulses in the drilling mud 114, during directional
drilling. The pulses representing the tool face readings are
decoded by the decoder 38, and the resulting information is
transmitted to the display module 18 for interpretation and
analysis by the technicians or engineers directing the drilling
operation.
[0086] The system 10 can be signaled to begin acquiring and
transmitting tool face readings upon the start of directional
drilling, in any suitable manner. For example, the direction
measurement unit 12 can be programmed to begin acquiring and
transmitting tool face readings if the flow of the drilling mud 114
is interrupted, i.e., stopped, for a relatively short,
predetermined time period.
[0087] The predetermined time period preferably is less than the
time required for the direction measurement unit 12 acquire data
from the magnetometers 20 and the accelerometers 22, calculate the
associated azimuth and inclination readings, and store the readings
in the associated registers. The direction measurement unit 12 can
be programmed with a delay so that the azimuth and inclination
readings are not stored, for example, until approximately one
minute has elapsed after the flow of drilling mud 114 has been
stopped.
[0088] The azimuth and inclination readings are stored in registers
within the memory-storage device 30 of the direction measurement
unit 12, as discussed above. These registers are zeroed upon
transmission of the readings to the encoder 36. Moreover, the
registers will continue to read zero until the flow of drilling mud
114 has been stopped for a period of time sufficient for the
direction measurement unit 12 to acquire and store a new set of
azimuth and inclination readings.
[0089] The direction measurement unit 12, upon activation,
therefore will read zeros in the noted registers if the flow of
drilling mud 114 has been stopped for less than approximately one
minute. The direction measurement unit 12 can be programmed to
begin generating and transmitting tool face readings under such
circumstances. In other words, the direction measurement unit 12
will begin generating and transmitting tool face readings when,
upon activation, the registers that store the azimuth and
inclination readings in the memory storage device 30 read zero.
[0090] Hence, the drill-rig operators, technicians, or engineers
can initiate the generation and transmission of tool face readings
by activating the mud pump 116, and then deactivating the mud pump
116 for a time period, e.g., thirty seconds, that is less than the
time required for the direction measurement unit 12 acquire data
from the magnetometers 20 and the accelerometers 22, calculate the
associated azimuth and inclination readings, and store the readings
in the memory storage device 30.
[0091] Directional drilling can continue until the drift of the
bore 112 has been returned to within limits. The direction
measurement unit 12 can be programmed to cease generating tool face
readings at this point, based on cessation of the flow of drilling
mud 114 as indicated by the switching device 70. In addition, the
direction measurement unit 12 can deactivate the telemetry system
14.
[0092] Vertical drilling can be restarted, after the direction
measurement unit 12 has been given sufficient time to acquire
static survey data to verify that the drift of the bore 112 has
returned to within limits.
[0093] The system 10 can be used to initiate corrective action
during vertical drilling operations, without a need to remove the
drill string 100 from the bore 112 for reconfiguration. In
particular, the system 10 permits directional drilling to be
performed without a need to access the bottom hole assembly 102 to
add an MWD tool. Hence, potential delays associated with the need
to retrieve and reconfigure the bottom hole assembly 102 can be
avoided.
[0094] Moreover, the system 10 permits a particular type of
relatively high-value information, such as tool face readings, to
be acquired and transmitted on a selective basis, without a need to
physically reconfigure the drill string 100. In other words, the
system 10 gives the user the option of acquiring certain types of
information only when the information is needed. This potential can
be commercially exploited in various ways.
[0095] For example, in applications where the system 10 is leased
to the end user, the usage rate can be allocated based on the
amount of a particular type of information acquired. In other
words, the customer can be charged at first usage rate for the time
period during which the system 10 is generating and transmitting a
particular type of data, e.g., relatively high-value data such as
tool face readings. In applications where the system 10 is used to
generate and transmit a second, lower-value type of data, the
customer can be charged a second, lower usage rate (or no usage
rate at all) for the time during which the system 10 is used to
generate and transmit the second type of data.
[0096] The system 10 can include provisions to restrict access to
high-value information such as tool-face readings. For example, the
output module 18 can include a processor 69 that is programmed to
permit the display or recording of tool-face readings only upon
entry of a password. Alternatively, the processor 69 can be
programmed so that a dongle must be used to gain access to tool
face readings. The dongle can be, for example, a hardware key
inserted into a serial or parallel portion of the output module 18,
a key diskette, or other suitable security device.
[0097] Alternatively, access to tool-face readings can be
restricted by configuring the decoder 38 to decode or transmit the
tool-face readings only upon the input of a password, or the use of
a dongle. Other components of the system 10 can be configured to
restrict access to the tool face readings, in other alternative
embodiments.
[0098] In other alternative embodiments, access to high-value
information such as tool-face readings can be restricted to owners,
lessees, or renters of additional display or data processing
devices that can be added to the basic system, and contain or use
proprietary software that makes the high-value information more
usable or accessible. Such devices can include, for example,
dedicated rig-floor displays, computers, hand-held devices such as
PDAs, or other suitable devices.
[0099] According to one method of using the system, the owner of
the system leases it to a drill rig operator configured such that
while certain information is continuously available to the drill
rig operator, the transmission or accessibility of tool-face
readings is disabled and can only be enabled by entry of a password
that is not provided to the rig operator as part of the lease
arrangement. If the rig operator determines that a need exists for
tool-face readings, in order to make a directional correction, for
example, the owner dispatches a technician to the drill site, at an
additional cost. The technician has the password that allows him,
and only him, to switch the configuration so that tool-face
readings become available. After sufficient too-face readings are
obtained, e.g., the drill rig operator is satisfied that the
drilling direction is back on course, the operator releases the
technician, who returns the tool to its original configuration in
which tool-face readings are no longer available. If tool-face
readings later become again required, the system owner dispatches
the technician and the process is repeated. Thus, in addition to a
licensing fee, the system owner recognizes an additional source of
income for service charges associated with the technician's
retrieval and/or use of tool-face reading.
[0100] The foregoing description is provided for the purpose of
explanation and is not to be construed as limiting the invention.
While the invention has been described with reference to preferred
embodiments or preferred methods, it is understood that the words
which have been used herein are words of description and
illustration, rather than words of limitation. Furthermore,
although the invention has been described herein with reference to
particular structure, methods, and embodiments, the invention is
not intended to be limited to the particulars disclosed herein, as
the invention extends to all structures, methods and uses that are
within the scope of the appended claims. Those skilled in the
relevant art, having the benefit of the teachings of this
specification, may effect numerous modifications to the invention
as described herein, and changes may be made without departing from
the scope and spirit of the invention as defined by the appended
claims.
[0101] Alternative embodiments of the system 10 can be configured
to generate and transmit information other than tool face, azimuth,
inclination readings. For example, readings of weight on bit,
torque on bit, vibration, temperature, pressure, etc., can be
generated and transmitted on a selective basis, in the
above-described manner.
PARTS LIST
[0102] System 10 [0103] Direction measurement unit 12 [0104]
Telemetry system 14 [0105] Signal processor 16 (direction
measurement unit 12) [0106] Display module 18 [0107] Pressure
barrel 19 [0108] Magnetometers 20 [0109] Accelerometers 22 [0110]
Housing 23 (of probe 19) [0111] Microprocessor 28 (of signal
processor 16) [0112] Memory-storage device 30 [0113]
Computer-executable instructions 32 [0114] Encoder 36 [0115]
Decoder 38 [0116] Pulser 40 [0117] Pressure transducer 42 [0118]
Computing device 44 (of display module 18) [0119] Strip-chart
printer 46 [0120] Microprocessor 50 (of encoder 36) [0121]
Memory-storage device 52 [0122] Computer-executable instructions 54
[0123] Microprocessor 58 (of decoder 38) [0124] Memory-storage
device 60 [0125] Computer-executable instructions 62 [0126]
Strip-chart recorder 66 (of display module 18) [0127] Computing
device 68 [0128] Processor 69 (of output module 18) [0129]
Switching device 70 [0130] Battery 72 [0131] Stator 88 (of pulser
40) [0132] Passages 90 [0133] Rotor 92 [0134] Drill string 100
[0135] Drill pipe 101 [0136] Bottom hole assembly 102 (of drill
string 100) [0137] Drill bit 104 [0138] Drill collar 106 [0139]
Motor 107 [0140] Drilling rig 108 [0141] Turntable 109 [0142] Earth
formation 110 [0143] Bore 112 [0144] Drilling mud 114 [0145] Rotary
steerable tool 118
* * * * *