U.S. patent application number 16/397456 was filed with the patent office on 2019-08-22 for methods and apparatus for confirmation time break (ctb) determination and shotpoint in-situ recording in seismic electronic deto.
This patent application is currently assigned to Austin Star Detonator Company. The applicant listed for this patent is Austin Star Detonator Company. Invention is credited to Larry S. Howe, Bryan E. Papillon, Gimtong Teowee.
Application Number | 20190257963 16/397456 |
Document ID | / |
Family ID | 54767548 |
Filed Date | 2019-08-22 |
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United States Patent
Application |
20190257963 |
Kind Code |
A1 |
Papillon; Bryan E. ; et
al. |
August 22, 2019 |
METHODS AND APPARATUS FOR CONFIRMATION TIME BREAK (CTB)
DETERMINATION AND SHOTPOINT IN-SITU RECORDING IN SEISMIC ELECTRONIC
DETONATORS
Abstract
Seismic blasting methods and apparatus are presented in which
detonator confirmation time break (CTB) is accurately determined by
maintaining an applied voltage across detonator leg wires following
initiation of a firing command or signal and sensing one or more
electrical parameters such as voltage and/or current, and
selectively identifying a CTB representing a time at which the
monitored electrical parameter indicates a successful
detonation.
Inventors: |
Papillon; Bryan E.;
(Phoenixville, PA) ; Howe; Larry S.; (Norwalk,
OH) ; Teowee; Gimtong; (Westlake Village,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Austin Star Detonator Company |
Cleveland |
OH |
US |
|
|
Assignee: |
Austin Star Detonator
Company
Cleveland
OH
|
Family ID: |
54767548 |
Appl. No.: |
16/397456 |
Filed: |
April 29, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15314726 |
Nov 29, 2016 |
10310109 |
|
|
PCT/US2015/032355 |
May 26, 2015 |
|
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16397456 |
|
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|
62009023 |
Jun 6, 2014 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01V 1/06 20130101; G01V
1/104 20130101; F42D 3/06 20130101; G01V 2210/1299 20130101 |
International
Class: |
G01V 1/06 20060101
G01V001/06; F42D 3/06 20060101 F42D003/06; G01V 1/104 20060101
G01V001/104 |
Claims
1. A method for logging seismic electronic detonators, the method
comprising: using a logger, reading a serial ID from a connected
electronic detonator; receiving a shot point number in the logger;
using the logger, electronically transmitting the shot point number
to the electronic detonator; and storing the shot point in the
memory of the electronic detonator.
2. The method of claim 1, wherein the logger is a seismic
logger.
3. The method of claim 1, wherein receiving the shot point number
comprises receiving a user-entered shot point number via a user
interface of the logger.
4. A method for data reporting in a seismic blasting system, the
method comprising: using a seismic blasting machine, electronically
obtaining detonator data including at least one of a serial ID and
a shot point from a connected seismic detonator; using the seismic
blasting machine, attempting to initiate detonation of the seismic
detonator; and transmitting the detonator data from the seismic
blasting machine to an external system.
5. The method of claim 4, wherein the external system is at least
one of a remote recording facility, a data acquisition system, and
a control system.
6. The method of claim 4, further comprising: selectively
identifying a confirmation time break value associated with the
attempted detonation; and transmitting the confirmation time break
value from the seismic blasting machine to the external system.
7. A method, comprising: using a seismic blasting machine,
electronically obtaining detonator data including at least one of a
serial ID and a shot point from a connected seismic detonator; and
storing the detonator data in a local memory of the seismic
blasting machine.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/314,726, filed Nov. 29, 2016, entitled
METHODS AND APPARATUS FOR CONFIRMATION TIME BREAK (CTB)
DETERMINATION AND SHOTPOINT IN-SITU RECORDING IN SEISMIC
DETONATORS, which is a national stage entry of International
Application Number PCT/US2015/032355 that claims priority to and
the benefit of, U.S. Provisional Patent Application No. 62/009,023,
file Jun. 6, 2014, and entitled METHODS AND APPARATUS FOR
CONFIRMATION TIME BREAK (CTB) DETERMINATION AND SHOTPOINT IN-SITU
RECORDING IN SEISMIC DETONATORS, the entirety of which applications
are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure involves seismic blasting technology
in general, and particularly relates to confirmation time break
determination and in-situ records of shotpoints in seismic
electronic detonators.
BACKGROUND
[0003] Seismic exploration is a process for assessing the
characteristics of underground land formations by generating and
sensing seismic waves. In general, an acoustic energy source
generates seismic acoustic waves which travel through subterranean
formations. The waves are reflected back to the surface by
formation interfaces associated with different formation densities,
and the waves may also be refracted to travel along the interface
before returning to the surface. Seismic detonators and associated
booster charges are placed in boreholes at or near the surface to
provide a seismic wave source. Geophones or other acoustic energy
transducers detect the acoustic waves reflected or refracted back
to the surface, where an array of such transducers is typically
positioned at the surface for land surveys with individual
transducers spaced from one another at known intervals and
distances from the seismic source. Data from the transducers can be
correlated in time with the time at which the seismic source was
actuated (detonated), and analyzed to provide information regarding
the structure of the earth underneath the transducers, for example,
in oil and gas exploration.
[0004] The time when the seismic source detonator fires is known as
the "time break", and it is desirable to confirm actual detonation
of a seismic charge by providing a value known as a confirmation
time break (CTB) indicating an actual time at which a seismic
detonator was successfully fired, either directly as a real-time
value or as a time difference between the actual firing and the
time at which the firing command or signal was issued. In
particular, certain applications involve a large number (e.g.
thousands) of acoustic sensors or transducers connected to data
acquisition systems for obtaining acoustic sensor data, and
operation of the sensors and data acquisition system is expensive.
Thus, enabling transducers and acquiring corresponding data is
costly if a seismic detonator does not actually detonate an
associated booster charge. Consequently, confirmation of actual
successful seismic source detonation by way of a confirmation time
break signal or value is highly desired to signal the seismic data
acquisition to enable the array of transducers in the field.
[0005] In the past, the time break was usually confirmed by
detecting a current surge into an electric detonator (e.g., current
interruption as described in U.S. Pat. No. 3,851,589 and monitoring
a derivative of current change described in U.S. Pat. No.
2,331,627), or a fixed predetermined delay after the transmission
of a firing command to an electronic detonator. However, the
seismic charge actually explodes some period of time after the
firing signal or command, and the time varies. As a result, the
reported time break does not represent the actual time of
detonation, leading to inaccuracy in temporal correlation of the
acoustic sensor data. Moreover, the provision of a firing signal or
command does not ensure that the detonator or the seismic charge
will go off, particularly if there is excessive leakage or shorts
in the bus wires for electric detonators. U.S. Pat. No. 6,704,657
describes the impedance monitoring of the detonation voltage and
current, with and without a small signal rf injection in electric
seismic detonators. In electronic detonators, the firing energy is
usually stored onboard inside the electronic detonator and the
current surge cannot be easily detected as a signal for the time
break. Furthermore, the issuance of the FIRE command in electronic
detonator does not always result in detonation all the time,
sometimes due to damage to the detonator or the wire during
loading. Thus conventional time break confirmation approaches may
cause a time break to be signaled to a data acquisition system, but
the detonator will not actually deploy, thereby increasing the cost
of seismic exploration through acquisition and storage of useless
data. Thus, it is desirable to provide more reliable techniques for
detection and signaling of electric and electronic detonator time
break values.
[0006] Seismic exploration using seismic sources and transducers
rely upon accurate mapping and knowledge of seismic source location
as well as the location of individual geophones. Shotpoints are
used in seismic exploration to denote the grid location record of a
seismic charge containing the detonator placed specifically in the
array to be explored. This may contain the geographical records and
other data. The shotpoint may be an 8-digit number e.g., 60531975
or 60611975, etc., which can be associated with a particular
detonator based on the location in an exploration map at which the
detonator and corresponding booster charge are to be placed, and
are usually stored in a data acquisition system or other external
media. Consequently, once a seismic detonator is successfully
fired, further steps are needed to relay the corresponding
fired-detonator shotpoint back to a control station (e.g., a remote
recording facility sometimes referred to as a "doghouse"),
typically by manual radio communication and manual entry of the
detonator ID or shotpoint. Thus, it is desirable to improve seismic
exploration processes and systems to facilitate timely provision of
detonator shotpoint numbers and confirmation time break values for
confirmed detonations.
SUMMARY
[0007] Various aspects of the present disclosure are now summarized
to facilitate a basic understanding of the disclosure, wherein this
summary is not an extensive overview of the disclosure, and is
intended neither to identify certain elements of the disclosure,
nor to delineate the scope thereof. Instead, the primary purpose of
this summary is to present some concepts of the disclosure in a
simplified form prior to the more detailed description that is
presented hereinafter. The disclosure relates to methods and
apparatus for seismic blasting by which the foregoing and other
shortcomings may be mitigated or overcome for improved reliable CTB
determination and signaling which can be used in connection with
electric, non-electric and electronic detonators. In addition, the
present disclosure advantageously provides for storage of shotpoint
information in-site within a memory of an electronic detonator for
automated reading or retrieval by a seismic blasting machine,
thereby facilitating timely reporting of the shotpoint information
and an accurate CTB to a data acquisition system or other external
system. In various implementations, the shotpoint can be
transmitted to the data acquisition system or doghouse (remote
recording facility) when first obtained by the seismic blasting
machine, followed by a transmission of the CTB upon successful
operation of the detonator, or these values can be reported
together after successful detonation.
[0008] Methods are provided for CTB value generation in a seismic
blasting system according to one or more aspects of the present
disclosure. The methods include applying a voltage from a seismic
blasting machine across a pair of wires connected to a seismic
detonator, and providing a fire command or a firing signal from the
blasting machine to the detonator. The method further includes
sensing one or more electrical parameters while maintaining the
applied voltage for a non-zero predetermined time after the firing
command or firing signal was provided, as well as determining
whether the sensed electrical parameter indicates a successful
detonation of an explosive charge associated with the detonator,
and if so, identifying a confirmation time break value representing
a time when the sensed electrical parameter indicates a successful
detonation.
[0009] A seismic blasting system data reporting method is provided
according to further aspects of the disclosure, including using a
seismic blasting machine to electronically obtain detonator data
including at least one of a serial ID and a shot point from a
connected seismic detonator, and to transmit the detonator data
from the seismic blasting machine to an external system. In certain
embodiments, the seismic blasting machine is used to attempt to
initiate detonation of the seismic detonator and selectively
identify a confirmation time break value associated with the
attempted detonation, and may also transmit the confirmation time
break value from the seismic blasting machine to the external
system. In various embodiments, moreover, the seismic blasting
machine may be used to determine whether the seismic detonator has
been successfully detonated, and if so to identify a confirmation
time break value associated with the detonation. The method in
certain embodiments may further include electronically reporting a
successful or unsuccessful detonation including transmission of the
detonator data from the seismic blasting machine to an external
system, where the external system in certain embodiments is a
remote recording facility, a data acquisition system and/or a
control system.
[0010] The seismic blasting machine and methods in further
embodiments may also include local storage of shotpoint in the
memory of the seismic blasting machine, alone or in combination
with storage, determination, and/or subsequent transmission of a
confirmation time break value.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The following description and drawings set forth certain
illustrative implementations of the disclosure in detail, which are
indicative of several exemplary ways in which the various
principles of the disclosure may be carried out. The illustrated
examples, however, are not exhaustive of the many possible
embodiments of the disclosure. Other objects, advantages and novel
features of the disclosure will be set forth in the following
detailed description of the disclosure when considered in
conjunction with the drawings, in which:
[0012] FIG. 1 is a partial sectional side elevation view
illustrating a seismic exploration system with a seismic blasting
machine connected to a detonator with a booster charge in a
borehole for generating seismic waves, and an array of seismic
transducers connected to a data acquisition system;
[0013] FIG. 2 is a schematic diagram illustrating an exemplary
seismic blasting machine with a firing circuit for actuating a
connected electric detonator as well as a power supply and a sense
circuit for detection of actual detonation;
[0014] FIG. 3 is a schematic diagram illustrating another seismic
blasting machine with a power supply and sense circuit for issuing
a fire signal to an electronic detonator and for detecting actual
operation of the detonator;
[0015] FIG. 4 is a detailed schematic diagram illustrating an
exemplary sense circuit for detecting actual detonation by
monitoring a voltage across leg wires and/or a current flowing
through the leg wires following issuance of a firing signal or
command;
[0016] FIG. 5 is a graph showing sensed voltage and sensed current
signals and corresponding detection thresholds in the seismic
blasting machine of FIG. 4;
[0017] FIG. 6 is a flow diagram illustrating an exemplary process
for entry and programming of a shotpoint number or value into an
electronic detonator in accordance with one or more aspects of the
disclosure; and
[0018] FIG. 7 is a flow diagram illustrating an exemplary method
for generating a confirmation time break (CTB) value in a seismic
blasting system according to further aspects of the disclosure.
DETAILED DESCRIPTION
[0019] Referring now to the figures, several embodiments or
implementations of the present disclosure are hereinafter described
in conjunction with the drawings, wherein like reference numerals
are used to refer to like elements throughout, and wherein the
various features and plots are not necessarily drawn to scale.
[0020] FIG. 1 illustrates an exemplary seismic blasting system 2
for seismic exploration, with a seismic blasting machine 4
connected by wires 10a and 10b to an electric or electronic
detonator 6 located within or proximate to a booster charge 8 of
explosive materials in a borehole below the surface of the ground
12. As seen in FIG. 1, the detonator 6 and booster charge 8 are
activated or "fired" by the seismic blasting machine 4 to generate
a seismic wave 14 that travels in the ground 12, with reflection
and refraction occurring at interfaces between ground structures of
different densities. The resulting waves 14 are sensed by acoustic
transducers such as geophones 16 staked into the surface of the
ground 12, where the transducers 16 provide output signals to a
data acquisition system 18. In a typical configuration, the data
acquisition system 18 is remote from the seismic blasting machine
4, with communications connections therebetween allowing the
blasting machine 4 and the data acquisition system 18 to exchange
signals and information. In operation, the waves 14 are detected by
the transducers 16 and the transducer data is recorded on magnetic
tapes, hard drives, or other storage media of the data acquisition
system 18 for subsequent data processing to determine subsurface
geological structures, for example, to potentially identify
structures favorable for accumulation of oil and gas in one
non-limiting application.
[0021] Referring also to FIGS. 2-4, FIGS. 2 and 3 illustrate
exemplary components of different embodiments of the seismic
blasting machine 4 in order to operate an electric detonator 6a
(FIG. 2) or an electronic detonator 6b (FIG. 3), and to selectively
identify or generate a confirmation time break (CTB) number or
value 62 (FIG. 4). The seismic blasting machine 4 includes one or
more processors and associated electronic memory 20, as well as a
communications interface 26 operative to provide communications
between the processor 20 and an external system such as the data
acquisition system 18 through any suitable wired and/or wireless
communications interconnections. For operation with an electric
detonator 6a (FIG. 2), the seismic blasting machine 4 includes a
firing circuit 28, such as a chargeable capacitor (e.g., 100 .mu.F
capacitor charged to 450 V) with suitable switching circuitry to
selectively discharge the capacitor through the leg wires 10 to
send a large current pulse as a firing signal to the electric
detonator 6a. In the case of an electronic detonator 6b (FIG. 3),
the blasting machine 4 includes a fire signaling interface 29
operatively connected to the leg wires 10 to provide a fire command
such as an encrypted signal through the wires 10 to a processor 30
of the electronic detonator 6b, where the detonator itself includes
an on-board firing circuit 34 (e.g., electronic ignition module or
EIM board) operable in response to receipt of the firing command to
activate the detonator 6b. In addition, as further discussed below,
the exemplary electronic detonator 6b in FIG. 3 includes an
electronic memory operatively coupled with the processor 30 in
which a shotpoint 32 is stored in certain embodiments.
[0022] In accordance with certain aspects of the present
disclosure, the seismic blasting machine 4 further includes a power
supply 22, in one example a DC power supply with positive and
negative terminals connected to the leg wires 10, along with a
sense circuit 24 connected to the leg wires 10 to sense one or more
electrical parameters associated with the connected detonator 6. In
one non-limiting example, the power supply 22 provides a DC voltage
to the leg wires 10 for a predetermined time TMAX, and the
illustrated sense circuit 24 includes voltage and current sensing
capabilities as described further below in connection with FIG. 4.
As seen in FIGS. 2 and 3, moreover, the firing circuit 28 in FIG. 2
(or the fire signal interface circuitry 29 in FIG. 3), as well as
the power supply 22 and the sense circuit 24 are operated under
control of the processor 20 of the seismic blasting machine 4. The
power supply 22 operates under control of the processor 20 to apply
a voltage across the wires 10 connected to the detonator 6, and the
firing apparatus (whether a powered firing circuit 28 or a fire
signal command interface circuit 29) operates under control of the
processor 20 in order to selectively provide a firing command or a
firing signal from the seismic blasting machine 4 to the seismic
detonator 6. The sensing circuit 24 is operatively coupled with the
processor 20 and senses one or more electrical parameters while the
processor 20 maintains the applied voltage from the power supply 22
for a non-zero predetermined time, referred to herein as TMAX after
a firing command or firing signal is provided to the detonator
6.
[0023] The processor 20, moreover, is programmed to automatically
determine whether the sensed electrical parameter indicates a
successful detonation of an explosive charge 8 associated with the
connected seismic detonator 6, and if so, selectively identifies a
confirmation time break value representing the time when the sensed
electrical parameter indicates a successful detonation of the
explosive booster charge 8. The processor 20 in certain
implementations responds to an external command through the
communications interface 26 (e.g., from a blasting control center,
from the data acquisition system 18, etc.) or from an included user
interface (not shown) to attempt to initiate a firing operation,
and accordingly actuates the firing circuit 28 (FIG. 2) or
transmits a firing signal via the interface 29 (FIG. 3). In
addition, the processor 20 in the illustrated embodiments activates
the power supply 22 and maintains provision of an applied voltage
via the power supply 22 for a time following initiation of the
detonator firing signal or command, while the sense circuit 24
senses one or more electrical parameters via the leg wires 10
and/or via an optional external sensor 58 disposed proximate the
detonator 6 and connected to an external sensor interface circuit
54 via extra leg wires 56a and 56b as seen in FIG. 4.
[0024] As best seen in FIG. 4, one embodiment of the sense circuit
24 includes a voltage sensing circuit 40 providing a sensed voltage
signal VSNS as an inverting input to a first comparator 44 for
comparison with a voltage threshold signal 42 (VTH) connected to
the comparator non-inverting input. In addition, this embodiment
further includes a sense resistor RS connected between the second
leg wire 10b and the return terminal of the power supply 22, and
the sense circuit 24 includes a current sensing circuit 48 coupled
to sense the voltage across the sense resistor RS, and thereby
provide a current sense signal ISNS to a non-inverting input of a
second comparator 50 for comparison with a current threshold signal
46 ITH. The outputs of the first and second comparators 44 and 50
are connected to an OR gate 52, which in turn provides a detonation
detection output signal to the blasting machine processor 20 as
shown in FIG. 4.
[0025] In response to receipt of a successful detonation signal
from the sense circuit 24, the processor 20 in certain embodiments
determines a current time and time stamps the detonation by sending
a confirmation time break value or number 62 indicating or
otherwise representing the time when the sensed electrical
parameter indicated a successful detonation of the explosive charge
8 proximate to the fired detonator 6. Any suitable CTB number or
value 62 can be generated by the processor 20 in various
embodiments. For example, the processor 20 may record a current
time at which the firing signal or command is generated via the
circuitry 28, 29, and determine a difference (e.g., in
milliseconds) between that time and the time at which the
confirmation signal is received from the sense circuit 24, and
provide this "Delta" as the CTB number or value 62. Using the time
at which the firing signal or command was generated and the Delta
value, the actual time at which the detonator successfully operated
can be determined by the data acquisition system 18 or other
external device. In another possible implementation, the seismic
blasting machine 4 and data acquisition system 18 cooperatively
correlate the initiation of the firing signal or command, with the
seismic blasting machine 4 providing a CTB message to the data
acquisition system 18 indicating that a proper detonation has been
sensed via the sensing circuit 24, in which the receipt of such a
CTB message 62 itself represents the confirmed time break for use
by the data acquisition system 18 (e.g., such a CTB message 62 need
not include an actual time value in all embodiments).
[0026] In certain embodiments, moreover, the seismic blasting
machine 4 may signal the data acquisition system 18 (e.g., via the
communications interface 26) that a firing signal or command has
been issued, and the data acquisition system 18 may be programmed
in certain implementations to await a subsequent receipt of a CTB
number, value, or message 62, whereupon the data acquisition system
18 activates the array of transducers 16 and begins acquiring
sensor data from the transducers 16. In this regard, the operation
of the seismic blasting machine 4 in the disclosed embodiments
advantageously refrains from sending a CTB value or message 62
until and unless the sense circuit 24 indicates a successful firing
by the detonator 6. In this manner, the blasting machine 4
advantageously avoids or mitigates the possibility of acquisition
and storage of useless data in the event that a firing signal or
command was issued but the connected detonator 6 did not
successfully detonate the booster explosive charge 8.
[0027] The blasting machine 4 in certain embodiments, moreover, may
report a successful detonation including the CTB value 62 from the
blasting machine 4 to an external system (e.g., data acquisition
system 18) if the sensed electrical parameter indicates a
successful detonation. In addition, certain embodiments of the
blasting machine 4 may also report an unsuccessful detonation from
the seismic blasting machine 42 such an external system 18 if the
sensed electrical parameter does not indicate a successful
detonation within the non-zero predetermined time TMAX after the
firing command or firing signal was issued. In certain embodiments,
moreover, the blasting machine 4 reports detonator data, such as
shot point and/or serial ID to an external system 18 without any
CTB value 62. In certain embodiments, the CTB value 62 can be
signaled is a real-time analog signal from the seismic blaster 4 to
the external system 18, and/or the CTB value 62 can be provided
through wired and/or wireless communications to the external system
18 is a digital value. In one possible implementation, the
processor 20 is programmed to maintain provision of the applied
voltage via the power supply 22 for 10 ms or more following
issuance of the firing signal or command, such as about 14 ms in
one non-limiting implementation. The predetermined time is
preferably set such that it exceeds with a certain margin of error
a typical range of detonation times, including the variability in
the timing between issuance of a firing signal or command and
successful operation of the detonator 6.
[0028] Referring to FIG. 5, in operation of certain embodiments,
the processor 20 of the seismic blasting machine 4 activates the
power supply 22 in order to provide a voltage from the blasting
machine 4 across the pair of wires 10 to the connected seismic
detonator 6, and thereafter provides the firing command or firing
signal to the detonator 6. In other possible implementations, the
activation of the power supply 22 can be at the same time the
firing signal or command is issued, or some short time thereafter.
As seen in FIG. 5, one possible detection technique employed by the
sense circuit 24 includes monitoring the voltage across the leg
wires 10a and 10b via the voltage sensing circuit 40 in FIG. 4, and
comparison of this sensed voltage VSNS with a voltage threshold VTH
42. The threshold 42 can be a predetermined voltage reference in
certain embodiments, connected to the non-inverting input of the
comparator 44 is shown in FIG. 4. As seen in the sensed voltage
graph 60 in FIG. 5, a firing signal or command is issued at time
T1, and thereafter the sensed voltage 40 undergoes a dip at time
T2, transitioning below the threshold 42. This causes the
comparator 44 to provide a logic "1" output (e.g., HIGH) to the
input of the OR gate 52, thereby causing the output of the OR gate
52 to be an active (e.g., HIGH) state to signal the processor 20
that the sensed voltage indicates successful detonation of the
explosive charge 8. The processor 20 of the seismic blasting
machine 4 accordingly timestamps T2 and issues this as the CTB
number or value 62. As previously mentioned, other implementations
are possible, for example, with the processor 20 issuing a time
value T2-T1 as the CTB number or value 62.
[0029] As further shown in the graph 62 of FIG. 5, the illustrated
sense circuit 24 also monitors the current flowing through the lead
wires 10 by sensing the voltage across the sense resistor RS via
the current sense circuit 48 providing a signal input ISNS to the
non-inverting input of the second comparator 50 for comparison with
a corresponding current threshold input 46 ITH. As seen in FIG. 5,
following issuance of the firing signal or command at T1, the
monitored current signal 48 undergoes an upward spike at T2,
thereby indicating that the detonator successfully caused explosion
of the booster charge 8. This causes the output of the comparator
50 (e.g., FIG. 4) to go active (e.g., HIGH), thereby causing the OR
gate 52 to output an active (e.g., HIGH) signal to the processor 20
of the blasting machine 4. As with the above described voltage
sense threshold 42, the current sense threshold 46 may be a
predetermined value, such as a fixed voltage reference within the
sensing circuitry 24 provided as an inverting input to the
comparator 50. In certain implementations, moreover, a dynamic
baseline system of the blasting machine 4 may be used to establish
a signal level threshold for one or both of the voltage threshold
42 and the current threshold 46 in order to mitigate the potential
for false detonation signals caused by low-level noise in the
blasting machine 4.
[0030] The inventors have appreciated that successful operation in
a seismic survey operation requires explosion of the booster charge
8, in addition to proper operation of the detonator 6. In this
regard, operation of the detonator 6 creates a shock wave within
the explosive material of the booster charge 8. This detonator
shock, in turn, ideally causes explosion of the booster charge
material 8, resulting in creation of plasma which is manifested as
a sudden decrease in impedance between the leg wires 10a and 10b.
The sense circuitry 24 in the seismic blasting machine 4 of the
illustrated embodiments detects this impedance change by threshold
comparison of one or more sensed electrical parameters (e.g.,
voltage, current, etc.), to detect a voltage dip (e.g., graph 60 in
FIG. 5) and/or a current spike (graph 62). Any other suitable
electrical parameter can be sensed based on connection of the sense
circuitry 24 with one or both of the leg wires in various
embodiments. For instance, any suitable impedance detection
circuitry 24 can be used by which a change in leg wire circuit
impedance can be detected for providing a corresponding
confirmation signal to the processor 20 when a successful
detonation has been sensed.
[0031] As seen in FIG. 4, an external sensor 58 may be provided in
the borehole along with the booster charge 8 and the detonator 6,
where the sensor 58 is connected by additional leg wires 56 to an
external sensor interface circuit 54 in the blasting machine 4, to
provide a corresponding external sensor signal to the processor 20.
For example, an extra set of leg wires 56 may be provided in
parallel with the detonator leg wires 10, and indeed may be wrapped
around the detonator 6 in certain implementations, with the
external sensor interface circuitry 54 connecting one end (e.g.,
wire 56b) to a circuit ground and the other end (e.g., 56a) through
a pull-up resistor to a positive supply voltage, where the external
sensor 58 is merely a short across the remote ends of the leg wires
56. In this case, the sense circuit 24 monitors the voltage of the
first leg wire 56a which is connected to circuit ground through the
second leg wire 56b in normal operation, and thereafter would be
pulled high through the pull-up resistor if the remote end of the
leg wire pair 56 is destroyed upon successful detonation by the
detonator 6.
[0032] In another possible example, a piezo sensor is mounted
outside the detonator shell and is connected to corresponding leg
wires 56, or such a sensor may be mounted inside an electronic
ignition module (EIM) circuit board (e.g., firing circuit 34) in an
electronic detonator 6b (FIG. 4), with the output of the sensor
providing a detectable voltage spike on the leg wires 56a, 56b upon
successful detonation, with the external sensor interface circuit
54 implementing a voltage comparison of the sensed voltage and a
corresponding threshold. In another possible embodiment, an
external sensor 58 may detect a light output from a photocell, CdS,
PMT, etc., and provide a corresponding signal along the leg wires
56 to the external sensor interface circuitry 54, which will
undergo a detectable signal pulse upon successful detonation.
[0033] In a further non-limiting example, the seismic blasting
machine 4 includes an RF signal generator within the external
sensor interface circuit 54, which provides a microwave signal to
the external sensor leg wires 56, with the external sensor 58 in
such embodiments including a microwave reflector impedance which
undergoes a detectable change upon successful detonation. In this
case, the sensor interface circuit 54 monitors a reflected signal
at the leg wires 56 and detects a change in a reflected signal to
selectively identify a successful detonation, and accordingly
signals the processor 20. In other possible implementations, the
sense circuit 24 detects voltage spikes and/or disturbances in
voltages at the leg wires 10 relative to ground, to thereby
indicate successful detonation based on the high voltage plasma
formation during detonation. Various other sensing implementations
are possible, wherein the described embodiments are merely
examples.
[0034] Referring also to FIG. 6, in accordance with further aspects
of the disclosure, electronic detonators 6b are provided with
electronic memory for in situ storage of a shot point number 32.
FIG. 6 provides a flow chart 70 illustrating programming of an
electronic detonator 6b. Although the exemplary method 70 and other
methods of this disclosure are illustrated and described
hereinafter in the form of a series of acts or events, it will be
appreciated that the various methods of the disclosure are not
limited by the illustrated ordering of such acts or events. In this
regard, except as specifically provided hereinafter, some acts or
events may occur in different order and/or concurrently with other
acts or events apart from those illustrated and described herein in
accordance with the disclosure. It is further noted that not all
illustrated steps may be required to implement a process or method
in accordance with the present disclosure, and one or more such
acts may be combined. The illustrated method 70 and other methods
of the disclosure may be implemented in hardware,
processor-executed software, or combinations thereof, such as in
the exemplary seismic blasting machine 4 and electronic detonator
6b shown in FIG. 4, and may be embodied in the form of computer
executable instructions stored in a non-transitory computer
readable medium, such as in the memory 20, 30 of the blasting
machine 4 and/or of the electronic detonator 6b in non-limiting
examples.
[0035] At 72 in FIG. 6, a seismic logger (not shown) reads a serial
ID from an electronic detonator 6b, such as during a logging
operation. At 74, an operator inputs a shot point number into the
seismic logger, and the logger sends the shotpoint number to the
electronic detonator at 76 for storage or "writing" to an in situ
memory at 78 in the electronic detonator 6b. In this manner, the
shotpoint 32 is stored within the electronic detonator 6b as shown
in FIG. 4, and the seismic blasting machine 4 can read this
information (e.g., alone or together with a serial ID or other
information) from the detonator 6 while connected to the blasting
machine 4. Thus, the processor 20 of the blasting machine 4 can
send the shotpoint 32 to an external device such as the data
acquisition system 18 as illustrated in FIG. 4 at any suitable time
during the seismic blasting operation. In addition, as previously
mentioned, the seismic blasting machine can determine and locally
store a CTB value 62 in its memory 20, and can transmit this to the
data acquisition system or other external device 18 via the
communication interface 26. Moreover, the seismic blasting machine
4 is configured in certain embodiments to locally store any or all
of the serial ID obtained from the detonator 6, a shot point number
obtained from the detonator 6, the CTB value 62 or other detonator
data in the local memory 20 of the blasting machine 4, and may
transmit any or all of these values, separately or in combination,
to an external system such as a remote recording facility, a data
acquisition system (e.g., system 18) or other control system, for
example, in a field recording station or doghouse in various
embodiments. These features advantageously allow an operator
performing recording operations to record data to match with a
logger record of a shotpoint, serial ID, or other detonator data
and/or CTB information.
[0036] Referring also to FIG. 7, a process 80 is illustrated for
operation of a seismic blasting system 2, and for generating a CTB
value 62. At 82 in FIG. 7, the blasting machine 4 reads a serial ID
and/or shotpoint 32 from a connected electronic detonator (e.g.,
detonator 6b in FIGS. 3 and 4). At 84, the seismic blasting machine
4 arms the detonator, for example, with the firing circuit 34 being
charged with suitable energy for initiating a detonation. A DC
voltage is applied at 86 from the seismic blasting machine 4 to the
leg wires 10, for example, with the blasting machine processor 20
activating the power supply 22 in FIG. 4.
[0037] At 88 in FIG. 7, the seismic blasting machine 4 issues a
fire command to the detonator 6b and starts a timer in one
embodiment. At 90, the seismic blasting machine 4 senses one or
more electrical parameters while maintaining the applied voltage,
and a determination is made by the processor 20 at 92 in FIG. 7 as
to whether the sensed electrical parameter indicates a successful
detonation of an explosive charge 8 associated with the seismic
detonator 6. As discussed above, the determination at 92 in one
non-limiting embodiment includes determining whether a sensed
voltage VSNS is less than a voltage threshold VTH and/or
determining whether a sensed current ISNS exceeds a current
threshold ITH.
[0038] If a successful detonation is detected (YES at 92), the
seismic blasting machine 4 records the current time as the CTB at
94, and reports a successful detonation at 96, which report can be
a message in certain embodiments including a previously read
detonator serial ID, shotpoint 32 and CTB value 62 to a data
acquisition system or other external device 18. If no successful
detonation has been detected (NO at 92), the processor 20 of the
blasting machine 4 determines at 98 whether the timer has exceeded
a predetermined time period TMAX, and if not (NO at 98), returns to
continue sensing the electrical parameter(s) while maintaining the
applied voltage at 92. If the designated amount of time has elapsed
with no successful detonation having been sensed (YES at 98), the
seismic blasting machine 4 reports an unsuccessful detonation
attempt at 99 in FIG. 7, for example, via a message to the data
acquisition system 18 that may include the detonator serial ID and
shotpoint 32. In this manner, the data acquisition system
immediately knows that a particular detonator was tried and did not
successfully detonate the associated charge 8, whereby the system
18 may refrain from gathering, and/or discard, and any associated
data obtained from the transducers 16.
[0039] The above examples are merely illustrative of several
possible embodiments of various aspects of the present disclosure,
wherein equivalent alterations and/or modifications will occur to
others skilled in the art upon reading and understanding this
specification and the annexed drawings. In particular regard to the
various functions performed by the above described components
(assemblies, devices, systems, circuits, and the like), the terms
(including a reference to a "means") used to describe such
components are intended to correspond, unless otherwise indicated,
to any component, such as hardware, processor-executed software
and/or firmware, or combinations thereof, which performs the
specified function of the described component (i.e., that is
functionally equivalent), even though not structurally equivalent
to the disclosed structure which performs the function in the
illustrated implementations of the disclosure. In addition,
although a particular feature of the disclosure may have been
disclosed with respect to only one of several implementations, such
feature may be combined with one or more other features of the
other implementations as may be desired and advantageous for any
given or particular application. Also, to the extent that the terms
"including", "includes", "having", "has", "with", or variants
thereof are used in the detailed description and/or in the claims,
such terms are intended to be inclusive in a manner similar to the
term "comprising."
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