Note: Descriptions are shown in the official language in which they were submitted.
~Q4'~596
This invention relates to methods and apparatus
for processing well logging measurements for recording on a
recording medium as a function of the depth at which said
measurements were obtained. The invention has special
application to recordingof well logging data with a cathode
ray tube recorder.
In producing well logging-measurements, a logging
tool containing one or more exploring devices is lowered
into a borehole drilled into the earth for measuring various
properties of the subsurface earth formations adjacent to a
borehole, or prDpertieS of the borehole itself. Such measure-
ments are of considerable value in determining the presence
and depth of hydrocarbon bearing zones that may exist in the
subsurface earth formations.
It is desirable in may instances to provide one
or more visible logs of the investigated subsurface phenomena
at the well site within a relatively short time after the log
has been run. In other cases, it is desirable to transmit
the well logging measurements to a remote location so as
to enable processing of the data by a digital computer and
thereby obtain valuable computed information. Such transmission
can be undertaken while the investigating apparatus is being
run through the borehole (real time) or at some later time
as by recording the measurements on magnetic tape for
subsequent transmission.
As is usually the case when such well logging data
is transmitted to a remote location, the well logging
measurements are converted into digital form for such trans-
mission. To provide a meaningful visual record of such
transmitted well logging measurements, it is necessary to
produce an analog type of presentation of the well logging
measurements, usually in the form of recorded traces whose
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positions on a recording medium are representative of the
amplitudes well logging measurements versus depth.
When well logging measurements in digital form are
transmitted from one location to another, it is sometimes the
case that the transmitting tape includes data from two or
more magnetic tapes which have been merged onto the transmitting
tape. Such merging of data produces a large number of
measurement channels on a single tape. (Each channel corresponds
to a separate information source.) To adequately produce an
analog recording of such merged data puts harsh design criteria
on a recorder for recroding all of this merged data in analog
form. To record such merged well logging aata as well as
unmerged data in the past, a galvanometer type of recorder has
been used. In such a galvanometer recorder a plurality of
galvanometer mirrors assume an angular orientation in proportion
to the amplitude of the well logging measurement to be recorded
such that light reflected off the mirror onto a nearby film
will assume the proper position on the film. Unfortunately,
a separate galvanometer mirror is required for each and every
channel of data to be recorded. While there have been
usually, though not always, a sufficient number of recording
channels in currently used galvanometer recorders to provide
real time recording of well logging measurements (i e.,
recording of the measurements as they are derived from the
investigating apparatus in the borehole), such is not always
the case when recording merged data because of the large
number of channels to be recorded.
It is, therefore, an object of the present invention
to provide new and improved methods and apparatus for recording
well logging data and, more particularly, for-recording in a
large number of channels of well logging data with one recording
device.
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To accommodate such a large number of signal channels,
a cathode ray tube recorder can be utilized for recording as
many channels of data as desired. To accomplish this, the
cathode ray tube beam is repetitively swept across the face of
the cathode ray tube while being modulated as a function of
the signals to be recorded. To accomplish this modulation,
the ramp signal which causes the sweep of the beam across
the face of the tube is compared with the well logging signals
to be recorded and when the ramp signal amplitude equals the.
well logging signal amplitude, the cathode ray tube beam is
unblanked to produce a mark on the film. By so doing, as
many well logging signals as desired can be recorded.
If the sweep rate is maintained constant, the
frequency.of each well logging signal to be recorded will
affect the presentation on the film. That is to say, since
a mark or image is placed on the film once per sweep for each
well logging signal to be recorded, the spacing between such
marks will be dependent on the rate of change of the well
logging signal to be recorded. Thus, if a DC signal is being
recorded, the spacing between each mark will be much closer
than for the case where a high frequency AC signal is being
recorded. Without special provisions being made, the recorded
high frequency signal will tend to look washed out when comparèd
with the recorded DC signal.
It is, therefore, another object of the present
invention to provide new and improved methods and apparatus for
recording well logging signals wherein the frequency of the
signals being recorded does not adversely affect the visual
presentation of such signals.
When recording data from a plurality of channels on
one portion of a recording medium, it is usually desirable to
code one or more of the traces being recorded to enable easy
`' ~047596
identification of the recorded traces corresponding to each
measurement. Such coding usually takes the form of dotting
or dashing, or both, one or more of the recorded traces.
However, variations in the frequency of the signals to be
recorded will tend to vary the coding produced on the film.
For example, if the coding takes the form of dashing the
recorded trace, the length of each dash (and space between
dashes) will vary as a function of the frequency of the well`
logging signals.
It is, therefore, another object of the present
invention to provide new and improved methods and apparatus
for producing a uniform coding pattern regardless of the fre-
quency or rate of change of the signals to be recorded.
When recording a plurality of well logging measure-
ments on one portion of a recording medium, the interval be-
tween certain ones of the recorded traces is often indicative
of certain subsurface characteristics. An example of this can
be found in U.S. Patent No. 3,166,708 granted to M.L. Millican
on January 19, 1965. When recording a plurality of well log-
ging measurements on one portion of a recording medium, it be-
comes difficult to visually identify the areas between selected
ones of the recorded traces on the recording medium. This is
especially true when the recorded traces crisscross back and
~orth.
It is, therefore, another object of the present
invention to provide new and improved methods and apparatus
for selectively coding the areas between recorded traces on a
recording medium to provide easy identification of certain
subsurface characteristics.
Many times, a particular formation parameter can
be identified by the area between two recorded traces only when
the trace corresponding to one well logging measurement is on
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" ~t)47596
a particular side of the other trace, i.e., one signal amplitude
is greater than the other. In this case, when the two traces
crisscross, the relationship of the two recorded traces to one
another will no longer be meaningful relative to the part-
icular formation parameter.
It is another object of the present invention,
therefore, to provide new and improved methods and apparatus
for recording well logging data in such a manner that the area
between selected traces can be readily indentified.
Along with recording the well logging measurements,
it is desirable to provide visual indications on the recording
medium of the depth levels from which the well logging
measurements were obtained. When such well logging measurements
are in digital form, the depth data is usually also in digital
form thus requiring some processing of the digital depth data
to enable depth numbers to be periodically recorded on the
recording medium.
It is, therefore, another object of the present
invention to provide new and improved methods and apparatus
for processing digital depth data for recording on a recording
medium.
While these recorded depth numbers provide easy
identification of the absolute depth of the logs, it would be
undesirable to record such depth numbers at frequent intervals.
Such frequent recording of these depth numbers would undesirably
clutter the log. However, it would be desirable to be able to
identify the depth of these logs at more frequent intervals than
woula be provided by a relatively infrequent recording of the
depth numbers. This can be accomplished by recording depth
lines at selected intervals. In this connection, it would be
desirable to provide readily indentifiable indications on the
recording medium of selected increments of depth.
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It is, therefore, still another object of the present
invention to provide new and improved methods and apparatus
for recording depth lines in a manner to provide easy
identification of different depth increments.
When using a cathode ray tube for recording purposes,
it would be desirable to monitor the beam current of the
cathode ray tube and maintain this current at a relatively
constant level so as to produce a relatively constant exposure
on the film. However, since the beam is being modulated, i.e.,
unblanked at unpredictable positions of its sweep across the
face of the CRT, it is difficult to know just when to measure
the beam current.
It is, therefore, yet another object of the present
invention to provide new and improved methods and apparatus for
measuring the beam current of a cathode ray tube for purposes
of maintaining a relatively constant film exposure.
When recording well logging data, a recording
mechanism exposes selected portions of a film in accordance
with the information to be recorded. The exposed film must
then be developed, and dried, before one is able to inspect
the log. It would, however, be desirable to be able to inspect
the log at the same time the film is being exposed, which is
an impossibility with present recording devices.
It is, therefore, still another object of the present
invention to provide new and improved methods and apparatus
which enable immediate inspection of the data being recorded.
In accordance with the recording methods and apparatus
of the present invention, well logging signals, either in
analog or digital form, are derived from either an exploring
device in a borehole or from digital processing equipment
such as a digital tape recorder or telemetry equipment for
application to the recorder of the present invention. In a
1047S~6
desirable form, this recording eguipment comprises a cathode
ray tube recorder which, in response to a digitally generated
sweep signal, repetitively sweeps a beam across a recording
medium which is moved past this face at a rate dependent on
the depth at which the signals to be recorded were derived.
The well logging signals are processed and then used
to modulate the beam intensity.
To produce a constant density trace on the record
medium in accordance with a feature of the invention, the
length of the trace recorded on the record medium for each
sweep of the beam is varied as a function of the rate of
change of the well logging signal. This is accomplished by
comparing the sweep signal (whose amplitude is representative
of the position of the beam on the record medium) with delayed
and undelayed versions of the well logging signal and generating
a writing signal whose pulse width is representative of the
rate of change of the well logging signal. This writing signal
can be used to modulate the beam.
The recorded data can be coded to distinguish the
recorded signals (called logs) from one another (called line
coding) and to distinguish areas between logs from one another
(called area coding). Line coding is accomplished by
selectively inhibiting at least one portion of a writing signal
in dependence on the rate of change of the well logging signal~
to be recorded. Area coding is accomplished by generating a
coding pattern signal and modulating the beam with this
pattern signal to thereby produce the pattern on the record
medium. Conditional coding is accomplished by modulating the
beam intensity as a function of this coding pattern signal
only when two well logging signals assume a predetermined
relationship to one another.
The beam current of the cathode ray tube can be
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controlled by modulating the beam intensity with a constant
amolitude signal at a predetermined time during each sweep of
the beam. The beam current can then be measured at the proper
time during each sweep and this measured value used to adjust
the beam current to a desired level.
Depth information can be recorded in accoraance with
another feature of the invention. ~his can be accomplished by
writing each digit of a depth number in side by side positions
on record medium and/or by writing a prescribed number of lines
on the record medium for given incremental change in aepth.
Digital depth data from suitable digital processing equipment
can be used for these purposes.
In accordance with still another feature of the
invention, the well logging signals are displayed a depth
section at a time. To accomplish this, a CRT beam is
swept in one direction as a function of depth while it is
at the same time repetitively swept in a transverse direction
thereto. The beam is modulated with representations of the
well logging signals.
More particularly, there is provided apparatus for
recording or displaying well logging signals of the type represent-
ing well logging data as a f~nction of depth, comprising:
(a~ means for producing a well logging signal
representative of a subsurface characteristic at various depth
levels in a borehole;
(b) means responsive to saia signal for producing
- a writing signal which is at least in part representative of
the rate of change of said well logging signal;
(c) a recording medium;
(d) means adapted for directing energy at selected
pvsitions on said recording medium; and
g _
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`-' 10475'36
(e) means responsive to said writing signal for
modulating the apparent intensity of said energy.
In the apparatus defined in the previous paragraph,
t:he energy-directing means comprises:
a clock source for generating pulses;
counting means for counting said generated pulses;
digital to analog converting means responsive to
the accumulated count of said counting means for generatinq a
sweep signal representative of said accumulated count;
means responsive to the accumulated count of said
co~nting means attaining a predetermined count for resetting
said counting means to thereby cause said sweep signal to return
to an initial value;
means responsive to said sweep signal for sweeping
energy across said recording medium; and
said writing signal producing means comprising
means for comparing said sweep signal with said weii logginq
signal an~ generating said writing signal upon said compared
signals attaining a predetermined relationship to one another.
Further, in the apparatus described in the two
previous paragraphs, the means for directing energy toward a
medium comprises sweep means adapted for sweeping the energy
along a line transverse to the medium during successive sweep
intervals to place images in the form dots or linear marks on
the medium; and wherein said intensity modulating means comprises
timing means for controlling placement of the images in the
direction of such line with reference to an initial position,
and means for controlling the level of the energy to regulate
the intensity, said timing means providing clock pulses for
digitally generating a sweep signal to control the sweep
means and a reset signal to determine the sweep duration,
and said level control means being responsive to each of said
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signals to determine the placement and linear extent of the
images and thereby the apparent intensity of lines, traces
or patterns to be formed by such images.
There is further provided a method of recording
well logging data comprising the steps of:
producing a well logging signal representative
of a subsurface characteristic at various depth levels
in a borehole;
generating a writing signal in response to said
well logging signal, which writing signal is in part
representative of the rate of change of said well logging
signal;
directing energy at a recording medium; and
controlling the apparent intensity and position
of said energy in response to said writing signal so as to
determine the position and linear extent of recorded images.
For a better understanding of the present invention,
together with other and further objects thereof, reference
is had to the following description taken in connection with
the accompanying drawings, the scope of the invention being
pointed out in the appended Claims.
Referring to the drawings:
FIGURE 1 is a block diagram representation of one
embodiment of well logging data recording apparatus
constructed in accordance with the present invention;
FIGURE lA shows a portion of the FIGURE 1 system
in greater detail;
FIGURES 2A-2G are waveform diagrams useful in
explaining certain features of the Figure 1 system;
FIGURE 3 illustrates an example of a recording
medium on which scale lines have been recorded when utilizing
the Figure 1 system;
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1(~47S96
FIGURES 4A and 4B show certain portions of the
.Figure 1 system in greater detail and will hereinafter be
referred to simply as Figure 4;
FIGURES 5A-5K, 6A-6F, and 7A-7F are waveform
diagrams useful in explaining the operation of the circuitry
of Figure 4;
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10~7596
FIGURE 8 is an example of a recording medium on
which depth lines have been recorded through utilization of
the Figure 4 circuitry;
FIGURE 9 is an example of a recording medium on
which both scale lines and depth lines have been recorded;
FIGURE lO illustrates a portion of the Figure 1
system in greater detail;
FIGURES llA-llE are waveform diagrams useful in
explaining the operation of circuitry of Figure lO;
FIGURE 12 is an example of a log or record produced
when utilizing the apparatus of Figure lO;
FIGURE 13 is a more detailed representation of still
another portion of the Figure l system;
FIGURES 14A, 14B and 14C show a more detailed
representation of still another portion of the Figure 1 system
and will be hereinafter referred to simply as Figure 14;
FIGURES 15A-15L illustrate examples or recordings
produced through utilization of the apparatus of Figure 14;
FIGURES 16A-16G illustrate waveform diagrams useful
in explaining the operation of the apparatus of Figure 14;
EIGURES 17A and 178 show still other portions of
the Figure 1 system in greater detail and will be hereinafter
referred to as Figure 17;
FIGURE 18 shows a well tool in a borehole along
with recording apparatus constructed in accordance with the
present invention; and
FIGURE l9 shows still another embodiment of recording
apparatus constructed in accordance with the present invention.
Now referring to Figure l, a digital information
source 20 produces output signals which are utilized by the
recording apparatus of the present invention to provide
recordings of such signals. This information source 20 can
~047596
take the form of a digital telemetry transmitter receiver such
as the system shown in Miller et al U.S. Patent 3,~99,156 of
August 10, 1971. For present purposes, it will be assumed
that the information source 20 takes the form of the digital
telemetry system shown in the said Miller et al U.S. Patent
3,599,156.
The telemetry system described in this copending
Miller et al application is a tape-to-tape synchronous digital
transmission system wherein data read from a tape at one
remote location is transmitted in serial form to a telemetry
receiver at another remote location and written on tape at
that remote location. At both the transmitting and receiving
locations, the telemetry equipment includes playback circuits
which convert the serial digital data to analog output signals
which are representative of the digital data. Additionally
this telemetry equipment includes provisions for playing back
a tape without transmission to convert the digital data on tape
to parallel analog signals. These parallel analog signals are
outputed from the telemetry equipment on the conductors 21.
The channels 1, 2, 3 ..... n designations on individual ones
of these conductors indicates the channel numbers of the data
being outputed from the telemetry equipment 20. Each channel
corresponds to a different information source or well logging
measurement. The outputed data can correspond to transmitted
or received data or it can take the form of data played back
from a tape without a simultaneous transmission.
These outputed well logging measurements are applied
to a plurality of parallel low pass filters 22 which operate
to filter out any transients caused by the commutating
operation within the telemetry equipment 20. The filtered
well logging signals are then applied to a plurality of
parallel pulse positions and pulse width modulators 23 which
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1(~47596
individually operate to produce writing signals for application
to subsequent circuits for further processing.
These individual modulators operate to compare a
sawtooth sweep signal from a sweep circuit 24 with the
individual well logging signals and produce writing signals
when the amplitudes of the two compared signals are sub-
stantially equal. In producing these writing signals, the
individual modulators operate to compensate for variations
in the frequency or rate of change of the individual well
logging signals. How this is accomplished will be described
in detail later.
The modulated signals are then applied to "parallel
line coding circuits" 45 where they are selectively coded so
that, when recorded on film or the like, the recorded traces
for each channel can be readily identified. The modulated
signals are also applied to area coding circuits 48 via an
area coding card reader 47. The area coding circuits 48
operate to generate area coding patterns which are recorded
between selected traces on the recording medium (e.g., film).
The area coding card reader 47 selects the patterns and the
signal channels for this coding operation. Both the line and
area coded signals are combined in a "combining and logic
circuit 42, as are other signals to be discussed later. The
combined signals are applied to a"CRT brightness control
circuit" 50 for application to the brightness control grids
of the cathode ray tube 25.
The sweep signal generated by the sweep circuit 24
is applied via a "CRT horizontal deflection circuit" 34 to the
horizontal sweep coils of the tube 25 for repetitively sweeping
the beam across the face of tube 25. The beam is modulàted
by the signals from the CRT brightness control circuits 50
to record traces on a recording medium (film) 36. Desirably,
~047596
the cathode ray tube 25 is of the fiber optic type in that
it has a fiber optic face plate for bringing about superior
resolution of the "spot" (beam striking the face) on the
recording medium 36.
The recording medium 36 is moved past the face of
the tube 25 at a constant rate by a constant speed motor 37
which moves the film at a rate determined by the transmission
rate of telemetry equipment 20. If desired, the motor 35
could be synchronized by the telemetry equipment 20.
Before proceeding with a detailed discussion of how
the writing signals are processed for application to a CRT
recorder, it would first be desirable to discuss the operation
of the sweep circuit 24 portion of the present invention in
detail. This sweep circuit 24 operates to periodically
generate pulses at a fixed frequency, count these pulses, and
produce a sweep signal for application to a cathode ray tube
and provide discrete digital signals for use by other circuits
in the Figure 1 system.
A pulse generator circuit 26 utilizes the 60 Hertz
power line for generating pulses a frequency of 120 Hertz.
(See Figure 2A.) The generator 26 can take the form of an
overdriven amplifier, clipping circuit, and monostable multi-
vibrator operating in conjunction to generate a pulse for
each zero crossing of the 60 Hertz signal. Each pulse
produced by the generator 26 sets a sweep control flip-flop
27 which, when set, enables an AND gate 28 to pass high
frequency pulses generated by a high frequency clock 29. (See
Figures 2B and 2C.) The pulses from the AND gate 28 designated
CL, are divided by two by a flip-flop 30 and applied to the
count input of a binary counter 31. As will be seen later,
the numerical state of the binary counter 31 corresponds to
the position of the beam on the face of a cathode ray tube.
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The binary counter 31 output is applied to a binary
to analog converter 32 which produces an analog voltage whose
magnitude increases in accordance with the increase of the
count state of the binary counter 31. Thus, as more and more
clock pulses are applied to the counter 31, the output voltage
of the binary analog converter 32 will correspondingly
increase. This output signal from the converter 32 is
designated the'sweep signal" and is shown in Figure 2D.
This sweep signal is applied to the modulators 23 as well as
to CRT horizontal deflection circuits 34 which process the
sweep signal in a manner to produce a linear sweep versus time
of the cathode ray tube beam across the face thereof. Thus,
the sweep signal can be referred to as a sweep position signal.
An "end of sweep matrix circuit" 35 responds to a
selected numerical count of binary counter 31 to produce a
reset pulse for resetting the sweep control flip-flop 27.
(See Figure 2E.) This sweep reset pulse is also applied to
various other circuits in the Figure 1 system for purposes to
be described later.
The output signals from each stage of the binary
counter 31 are also applied to a scale line circuit 37 which,
in response to selected count sequences of the binary counter
31, generates scale line signals used for writing scale lines
on the recording medium 36. To accomplish this, the output
signals from binary counter 31 are applied to a scale grid
card reader 38 which selects certain numerical outputs of the
binary counter 31 for application to one of a pair of one-shots
39 and 40. The one-shot 39 produces pulses having a pulse
width of time duration tl and one-shot 40 produces pulses
having a pulse width of time duration tl + t2. The output of
one-shots 39 and 40 are combined in an OR gate 41 for
application to combining and logic circuits 42. Figure 2F
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shows the resulting scale grid pulses.
The combining and logic circuit 42 processes these
pulses from one-shots 39 and 40 to produce scale lines on the
recording medium 36. The pulse width of the pulses from one-
shots 39 and 40 determine the length of the trace produced on
the recording medium 36 as the beam sweeps transversely across
the recording medium 36. These traces are shown in Figure 2F.
Since the recording medium is moving in a direction perpendic-
ular to the direction of this sweep, the writing time will
determine the width of the line produced on the recording medium
as the beam is repetitively swept thereacross. The card reader
38 enables any scale line pattern desired to be produced by
merely inserting the appropriate card therein. \
~ The scale line circuit 37 also includes an "initial
scale line one-shot" 43 which operates in response to the
leading or rising edge of the sweep control signal flip-flop
27 output signal to generate an "initial scale line pulse"
for application to the OR gate 41 and separately to the
combining circuits 42, as well as to other circuits to be
described later. Since, as seen in Figure 2B, the sweep
control signal rises at the initiation of the sweep signal of
Figure 2D, the one-shot 43 will operate to generate a pulse
at the beginning of each sweep, which pulse is used to
produce an initial scale line on the recording medium. The
reason for this separate treatment of the initial scale line
will be described later.
The writing signals from modulators 23 are
individually applied to separate ones of a plurality of
~arallel line coding circuits 45 which operate to code the
traces which are recorded on the recording medium 36. As
will be explained in more detail later, the coding circuits 45
operate to inhibit selected portions of the writing signals
~0~7596
to accomplish this coding operation. The coding circuits 45
also operate in response to the rate of change of the well
logging signals to vary the coding operation as a function of
this rate of change to enable uniform line coding regardless of
the rate of change of the well logging signals. To allow
selection of the particular type of coding to be applied to
the signals for each channel, the line coding card reader 46
instructs the line coding circuits 45 to apply selected
codes to signals from the different channels.
The writing signals from modulator 23 are also
app~ied to an area coding card reader 47 which selects
individual ones of the writing signals from modulators 23 for
application to individual coding circuits of the area coding -
circuits 48. The area coding circuits 48 include a plurality
of pattern generators which operate to individually produce
any one of twelve patterns on the recording medium 36.
Examples of these patterns are shown in Figures 15A-15L.
These patterns can indicate such subsurface constituents as
oil, gas, sand, porosity, water, limestone, etc.
As discussed earlier, it is usually the case that
the area between two recorded traces indicates the amount of
a particular subsurface constituent only when one of the
traces is on one or the other side of the other trace on the-
recording medium. To enable the area coding circuits 48 to
generate patterns only under the proper conditions, the area`
coding card reader 47 causes the card reader 47 to select
certain ones of the writing signals as "start" signals and
certain ones as "stop"signals. The start signals will signal
the circuits 48 to begin producing the area coding pattern and
the stop signals will cause the pattern to terminate. If the
selected start-stop signals are reversed, no pattern will be
produced.
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~047S96
Additionally, the line coded writing signals are
applied to a "trace intensifier card reader" 49 which, in
reponse to a selected card placed therein, selects certain ones
of the line coded writing signals for application to a special
input channel of the combining and logic circuit 42. The
circuit 42 operates to boost the amplitude of these selected
signals to thereby intensify the recorded trace for just
these signals. The combining circuits 42, among other things,
combines all of the line coded and area coded signals and
separately combines the trace intensified signals for all
channels for application to the CRT brightness control circuits
50. The combining circuits 42, in addition to combining these
signals, also includes suitable logic circuits which operate
to give preferential treatment to certain ones of the writing
signals applied thereto for purposes to be explained later.
The CRT brightness control circuits operate to
combine the line and area coded writing signals, the trace
intensified signals and scale line signals (as well as depth
line signals - to be discussed later) and produce signals for
modulating a grid of the cathode ray tube 25. The brightness
control circuits 50 also operate to monitor and control the
beam current produced by the cathode ray tube 25.
As discussed earlier, the cathode ray tube is
modulated by the writing signals produced from well logging
measurements at random time intervals, thus making it very
difficult to properly monitor the beam current for control
purposes. To circumvent this problem, in accordance with an
important feature of the present invention, the initial scale
line pulse from scale line circuit 37 causes the cathode ray
tube beam to be unblanked a specified amount and at a specified
time period during each sweep. This specified time is the
beginning of each sweep. To this end, the initial scale line
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pulse from the scale line circuit 37 is applied to the CRT
brightness control circuits 50 to inform the circuits as to
the time when the initial scale line is being written. As
will be explained in greater detail later, the CRT brightness
control circuits 50 operate in response to this initial scale
line pulse to sample the beam current and appropriately
adjust it, if necessary. By so doing, the beam current will
be maintained at the desired level.
The system of Figure 1 also operates in accordance
with other features of the present invention to record depth
information, e.g., depth lines and depth numbers on the
recording medium 36. To accomplish this, the initial depth
at which well logging measurements are derived is set into
depth determination circuits 60 by a plurality of initial
depth preset switches 61. Data from the telemetry transmitter
or receiver is thereafter utilized to continuously update the
depth determination circuits 60. The depth determination
circuits 60 continually provides data for a depth display
unit 62 so that a numerical representation of the depth of
the well logging signals outputed from the telemetry
transmitter or receiver 20 can be viewed at all times.
To update the depth determination circuit 60, pulse
code modulated data from the telemetry unit 20 is applied to
the depth determination circuit 60 for entry into an appropriate
register. The telemetry equipment 20 also supplies shift
pulses and a shift pulse window to the depth determination 60
to enable the pulse code modulation data to be shifted into
the register at only the time period when a depth word is
being transmitted or received. The shift pulses are applied
to this entry register under control of the shift pulse
window, the shift pulse window acting to insure that only the
necessary number of shift pulses are actually applied to this
iO~7596
entry register. The telemetry equipment 20 causes a depth
shift command pulse to be applied to the depth determination
circuits 60 to insure that only depth words are entered into
this entry register. The depth data in this entry register
is then shifted to another register by a gate control pulse
from the telemetry equipment 20 after the depth word has been
entered into this entry register. How the depth determination
circuits 60 utilize these signals from the telemetry equipment
20 will be described in detail later.
As mentioned earlier, the telemetry equipment 20
is described in the said Miller et al U.S. Patent 3,599,156.
In this United States Patent the pulse code modulated data is
derived from the wiper arm of a four position switch 70A in
Figure 15C of that application. The shift pulses are derived
from the output of an AND gate 205 in Figure 15A of the co-
pending Miller et al application and are designated "shift 14"
therein. The shift pulse window is derived from a one-shot
187 in Figure 15A of the copending Miller et al application
and is designated "tape write and depth display window"
therein. The depth shift command pulse is derived from the
wiper arm of a four position switch 70E in Figure 15A of the
said Miller et al U.S. Patent 3,599,156 and is designated
"command shift depth display" therein. The gate control
pulse is derived from a one-shot 188 in Figure 15A of the
said Miller et al U.S. Patent 3,599,156 and is designated "X4'
therein.
It is to be understood that the telemetry apparatus
for producing these above-described signals does not comprise
part of the present invention. Furthermore, it is to be
understood that any information source could be utilized as
the input to the recording apparatus of the present invention
and the invention is thus not limited to recording data from
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~0~7596
the telemetry equipment described in the copending Miller
et al appllcation.
The depth determination circuits 60 supply data
to a depth interval detector 63 which operates to generate
signals representative of 2', 10', 50' and 100' depth intervals.
The 2', 10' and 50' depth interval signals are applied to a
"depth line generator" 64 which operates to generate "depth
line writing signals" for application to the combining and
logic circuits 42 for subsequent recording. The depth line
generator 64 operates to generate one line for every 2 foot
depth interval, two lines for every 10 foot interval and four
lines for every 50 foot interval. The depth determination
circuit 60 also supplies data to a "digit selector circuit"
65 which processes the depth data and causes a numerical
display of the depth number by energizing a cathode ray tube
numerical display unit 67 vla a "depth driving CRT circuit"
66. The display unit 67 is positioned relative to the re-
cording medium 36 so as to record numerical representations
of the depth numbers on the recording medium 36. The digit
selector circuits 65 process the depth data from the depth
determination circuits 60 so that depth numbers will be
printed on the recording medium 36 when the last two digits
of the depth numbers are 96, 98, 00, 02, and 04. Thus, for
example, a digit of a depth number will be recorded at each of
2196 ft., 2198 ft., 2200 ft., 2202 ft., and 2204 ft. By so
doing, the depth number will appear sideways on the record
medium to minimize the width of the depth track.
The hundred foot depth interval signals from the
depth interval detector 63 are applied to a sawtooth generator
70 which operates to generate a timing signal having a time
period corresponding to 100 feet of data generated from the
telemetry equipment 20. This 100 ft. sawtooth signal is
104'7596
applied to a vertical deflection amplifier 71 which drives
the vertical deflection coil of a storage cathode ray tube
72. The horizontal sweep signal`from the-sweep circuit 24
is utilized to energize the horizontal sweep coil of the
storage cathode ray tube 72 via a horizontal deflection
amplifier 73. The CRT brightness control circuits 50 supply
the combined writing signals to the storage cathode ray tube
72 to modulate the beam intensity thereof.
By this arrangement, in accordance with another
feature of the present invention, the storage cathode ray
tube 72 will provide a visual display of up to 100 feet of
recorded data to thereby enable one to visually determinè
what data has been recorded on the recording medium 36. The
phosphor of the storage CRT 72 is erased at the end of each
100 ft. interval.
Now turning to Figure 4, there is shown the depth
determination circuits, initial depth preset switches, digit
selector circuits, depth interval detector and depth line
generator of Figure 1 in greater detail. First, concerning
the initial depth preset switches 61, five decade switches
80, 81, 82, 83, and 84 are set in accordance with the initial
depth of the data which is being transmitted or received by
the telemetry equipment 20. The decade switch 80 corresponds
to units of feet, the decade switch 81 to tens of feet, switch
82 to hundreds of feet, switch 83 to thousands of feet, and the
switch 84 to tens of thousands of feet. The ten contacts
of each decade switch are connected to individual decimal to
binary coded decimal converters 85 which operate to convert
the decimal number from each decade switch to a binary coded
decimal number.
The binary coded decimal numbers corresponding to
the tens, hundreds, and thousands foot switches are applied
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104'7S96
to the tens, hundreds, and thousands foot positions of a five
decade depth memory register 86 via OR gates 87. The units
and tens of thousands foot ~inary coded decimal numbers are
applied directly to the corresponding portions o~ the register
86.
To set the initial depth number into the register
86, a switch 87 is momentarily depressed so as to apply a
DC voltage to the wiper arms of the five decade switches 80-
84. Once the switch 87 is depressed, the memory register 86
will have stored therein the initial depth of the measurements
to be received from the telemetry equipment 20.
The depth memory register 86 is then continually
updated as data is transmitted, received or played back by
the telemetry equipment 20. To accomplish this, the pulse
code modulated data from the telemetry equipment 20 is entered
into a three-decade shift register 90. As discussed in the
said Miller et al U.S. Patent 3,599,156, depth words are
transmitted every ten feet. Thus, whenever a depth word is
entered into the depth register 90, it can be assumed that
the lowest order digit will always be zero.
Since the PCM data conductor from telemetry equip-
ment 20 has data therein continuously, the depth entry register
90 is activated only when a depth word is being transmitted or
received. To accomplish this, the shift pulses and shift
pulse window (which corresponds in time -to the generation of
the shift pulses) and the depth shift command pulse from the
telemetry equipment 20 are combined in an AND gate 91. The
resulting gated shift pulses from AND gate 91 are utilized to
shift the contents of the depth register 90 only when depth
words are being transmitted, received, or played back. By
this means, only depth words will be entered into thc depth
register 90.
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1047S96
After depth has been entered into the register 90,
a plurality of depth memory control gates 92 are energized by
the gate control pulse from the telemetry equipment 20 to
transfer the data in the depth register 90 to the tens,
hundreds, and thousands foot portions of the depth memory
register 86 via the OR gates 87. Thus, the tens,hundreds,
and thousands portion of the memory register 86 will be con-
tinuously updated while data is processed by the telemetry
equipment 20.
To update the units foot portion of the depth memory
register 86, the shift pulse window pulses from the telemetry
equipment 20 are divided by two by a flip-flop 93 and then
applied to the count input of the unit foot position of the
register 86. As discussed in the said Miller et al U.S. Patent
3,599,156, the shift pulse window pulses are generated once
per six inches of depth. Thus, the units foot porticns of the
depth memory register 86 will be updated at one foot intervals.
The register 86 counts down to correspond with the telemetry
operation. (Boreholes are logged from bottom to top and thus
the actual depth footage decreases.)
The contents of the depth memory register 86 are
applied in parallel fashion to the depth display unit 62 such
that a visual numerical display of the depth of the data being
transmitted, received or played back by the telemetry equipment
20 can be obtained at all times. The contents of the depth
memory register 86 are also applied to the digit selector
circuits 65, which as discussed earlier, operate to select
those depth numbers whose last two digit:s are 96, 98, 00, Q2,
and 04 for application to the cathode ray tube numerical
display device 67.
- To accomplish this, the binary coded decimal output
signals from the units and tens decade units of the depth
~047596
memory register 86 are applied to a pair of binary coded
decimal to decimal converters 95 and 96 respectively. The
count sequences for the combination of converters 95 and 96
are shown in Figure 5A. An AND gate 97 is responsive to the
zero digit of the converter 96 and the No. 4 digit of the
converter 95 for producing the pulse of Figure 5B for setting
a flip-flop 98. When set, the flip-flop 98, whose normal
output is shown in Figure 5C, enables an AND gate 99 to pass
a two foot depth signal from the depth interval detectors 63.
The gated two foot depth signal is shown in Figure 5D. tThis
two foot depth signal is obtained by dividing the one foot
depth signal from the flip-flop 93 by two with a divide by
two flip-flop 100 within the depth interval detector 63.)
Every two feet the leading edge of the gated two foot signal
from AND gate 99 advances a binary counter 101 and energize~
a one shot 102. The binary counter 101 count sequences are
shown in Figure 5E and the one shot 102 output pulses are
shown in Figure 5G.
The three stages of the binary counter 101 are
connected to a binary to decimal converter 103 which produces
an output signal on one of five output conductors during the
first five count sequences of the binary counter 101.
As stated earlier, depth numbers are printed on the
record medium 36 sequentially in reverse order as the record
medium moves past the depth number printing CRT 67 (see
Figure 1) and since depth numbers are printed every 100 feet,
the first two printed digits will be zero. Thus, the first
and second output sequences from converter 103 are combined
in an OR gate 112 and applied to the zero input position of
the CRT numerical display unit 67 via an AND gate 113. The
AND gate 113 is enabled by the output pulse from one-shot 102
to cause the CRT 67 to be flashed at the proper time and for
the proper time duration to enable an appropriate exposure time
-25-
1047S~36
on the film record medium 36.
The hundreds, thousands, and ten thousands binary
coded decimal signals from the depth memory register 86 are
applied to three parallel binary coded decimal to decimal
converters 104. The conjunctive combination of the third
sequence output signal from the binary decimal to decimal
converter 103 and the pulse from the one-shot 102 energizes
ten individual ~arallel gates 105 by way of an AND gate 106.
When energized, the gates 105 connect the ten output conductors
from the hundreds foot portion of the binary coded decimal to
decimal converter 104 to ten OR gates 107. The enabling
pulse from AND gate 106 is shown in Figure 5H.
The number 4 sequence output from the binary to
decimal converter 103 and the pulse from one-shot 102 are
combined in an AND gate 107 for energizing 10 parallel gate
circuits 108. When energized, the parallel AND gates 108
connect the ten output conductors from the thousands foot
portion of the binary coded decimal to decimal converter 104
to individual ones of the OR gates 107. The enabling pulse
from AND gate 107 is shown in Figure 5I.
In like fashion, the No. 5 sequence output from the
binary to decimal converter 103 is combined with the output
pulses from one-shot 102 in an AND gate 109 for energizing
the parallel AND gates 110 during the fifth sequence of the
binary counter 101. (See Figure 5K.) When energized, the
parallel AND gates 110 connect the ten output conductors
~ from the ten thousands foot portion of the binary coded
decimal to decimal converter 104 to individual ones of the OR
gates 107. The output from the 10 OR gates 107 are connected
to individual ones of the ten input terminals of the CRT
numerical display unit 67. The leading edge of the No. 5
sequence output signal resets the flip-flop 98 and thus the
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10~7596
AND gate 99 to prevent the counter 101 from being advanced
beyond sequence No. 5.
To reset the binary counter 101, an AND gate 111 is
responsive to the No. 2 output of the units foot position of
the binary coded decimal to decimal converter 95 and the nine
digit output of the tens foot output position of the binary
coded decimal to decimal converter 96 for resetting the
binary counter 101 whenever the tens and units digits of the
depth number are 92.
Summarizing the operation of the digit selector
circuit 65, whenever the last two digits of the depth number
are 04 as determined by the AND gate 97, the flip-flop 98 is
set to enable binary counter 101 to count the rising edges of
the two foot depth signal from the depth interval detector 63,
; as seen by inspecting Figures 5A-5D. As seen in Figure 5E, the
binary counter 101 counts five rising edges of the two foot
depth signal and then resets itself when the last two digits
of the depth number are 92.
During the first two sequences, the binary to
decimal converter 103 energizes the "zero" input of the nu-
merical display unit 67 by way of the OR gate 111. During
the third sequence, i.e., at a depth whose last two digits
are 00, the number for the hundreds foot digit is gated by
the parallel gates 105 to the proper input terminal of the
numerical display unit 67 by way of the OR gates 107. Thus,
for example, if the hundredths foot number is 6, the numerical
- display unit 67 will display the number 6 during sequence 3.
- During sequences 4 and 5 the thousandths and ten-thousandths
foot numbers are likewise gated to the proper input terminals
of the numerical display unit 67.
At the beginning of sequence 5, the flip-flop 98 is
reset to thereby disable advancement of the binary counter 101.
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iO~7596
The binary counter 101 is then reset after the entire number
- has been printed by the pulse from AND gate 111.
Taking an example of this operation assume that
the number to be printed is 5100 feet. At 5104 feet, the
flip-flop 98 will be set and the binary counter 101 will
advance to its first count sequence thus enabling the AND
gate 113 via OR gate 112. The pulse from one shot 102 then
energizes the zero digit of the display unit 67 and a zero
is printed at 5104 feet. Next, at 5102 feet the binary
counter 101 advances to its number two count sequence and
through the same operation a zero is again printed. At 5100
feet the binary counter 101 advances to its number three count
sequence, thus enabling the AND gate 106 to pass the pulse
from one shot 102 to the parallel gates 105. The hundredths
foot portion of binary coded decimal to decimal converter
104 will, at this time, be generating an output signal on
the number five output conductor such that when the gates 105-
are energized, the number five digit of the display unit 67
will be energized. Then at the number four sequence, the
number five output signal from the thousandths foo~ portion
of converter 104 will energize the number five digit of the
display unit 67. During the fifth sequence, the zero digit
of the display unit 67 will be flashed. Then at 4992 feet, a
safe time after the entire depth number has been printed, the
system will be reset in readiness for the same operation to
occur at 5004 feet for printing the depth number 5000.
Now concerning the depth interval detector 63, it
operates in reponse to data from the depth register 90 and
the divide by two flip-flop 93 to generate 2, 10, 50 and 100
foot signals. How the two foot signal is generated has
already been discussed. To generate the 50 foot signal, a
matrix circuit 120 is responsive to the tens foot portion of the
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i(~47596
depth register 90 to generate an output pulse every 50 feet.
To generate the 100 foot signal, a matri~ circuit 121 is
responsive to the hundreds foot portion of the depth register
90 to generate a pulse every 100 feet. The ten foot depth
pulses are obtained directly from the depth shift command
output of the telemetry equipment 20 since, as discussed
earlier, a depth word is transmitted every ten feet by the
telemetry equipment described in the copending Miller et al
application.
The hundreds foot depth pulses from the detector 63
are applied to the hundred foot sawtooth generator 70 of
Figure 1 to enable the hundred foot depth sweep for the
storage cathode ray tube 72.
The depth line generator 64 operates in response to
the 2, 10, and 50 foot depth signals from the depth interval
detector 63 to generate signals which causes a line to be
written on the recording medium every two feet, two lines to
be written every ten feet, and four lines to be written every
fifty feet. To accomplish this, referring to Figures 4 and
6A-6F in conjunction, and first concerning the two foot portion
of the depth line generator 64, the leading edges of the two
foot depth signals, shown in Figure 6A, set a flip-flop 125
which when set, enables an AND gate 126. The normal output of
flip-flop 125 is shown in Figure 6C. When enabled, the AND
gate 126 passes the sweep reset pulses, shown in Figure 6B, to
the set input of a flip-flop 127. The resulting gated sweep
reset pulses are shown in Figure 6D. The flip-flop 127 is set
on the trailing or falling edge of each gated sweep reset
pulse of Figure 6D. The trailing edge of each sweep reset
pulse also resets the flip-flop 125 via a NAND gate 128
which inverts the output pulses from AND gate 126 to enable
the pulse rising edges to reset flip-flop 125.
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~)47596
The normal output of flip-flop 127, shown in Figure
6]S,is applied to an OR gate 130. The output signals from
O]R gate 130 constitute the depth line signals which are applied
to combining and logic circuit 42 for eventually causing one
line to be swept transversely across the recording medium
25 every two feet. To insure that only one depth line is
printed every two feet, the normal output of the flip-flop 127
enables NAND gate 131 to pass the sweep reset pulses to the
reset input of the flip-flop 127 after one sweep of a depth
line has been completed. The output signals from NAND gate
131 is shown in Figure 6F.
To generate two such depth lines every ten feet is
the function of the ten foot depth line generator 133 of the
depth line generator circuitry 64. The ten foot depth line
generator 133 operates in an identical fashion as the two
foot depth line generator 124 except that a divide by two
flip-flop 134 prevents the control flip-flop corresponding to
flip-flop 127 of the two foot circuit 124 from being reset
until two sweeps have been completed and the two depth line
sweeps are initiated by the ten foot signal from depth
interval detector 63. Thus, during the time $hat it~takes
the cathode ray tube 25 to complete two sweeps, the output of
the OR gate 130 is maintained at the "one" level by the ten
foot line generator 133 to thereby produce two depth lines
on the record medium every ten feet.
To generate four depth lines every 50 feet, a 50
foot depth line generator 135 responds to the fifty foot depth
pulses from the depth interval detector 63. The fifty foot
depth line generator 135 operates in an identical fashion with
the two foot and ten foot depth line generators 124 and 133
except that a divide by four circuit 136 prevents the system
from resetting itself until four sweeps have been completed.
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~o47~s6
These elements in the 10 foot and 50 foot depth line generators
133 and 135 which are identical in operation with elements in
the two foot depth line generator 124 are designated the same
except for the addition of a letter a after the numbers for the
ten foot depth line generator 133 and the addition of a letter
b for the fifty foot depth line generator 135.
Figure 8 is an example of a recording medium with
the depth lines printed thereon through utilization of the depth
line generator circuit 64. In Figure 8 it can be seen that the
depth lines at lQ foot intervals are wider than the depth lines
at 2 foot intervals and that depth lines at 50 foot intervals
are wider and thus more outstanding in appearance than either
the two foot or 10 foot interval depth lines.
Now, turning to Figure 9, there is shown a
recording medium on which both depth and scale lines have been
printed, as well as the depth numbers. In addition to the dis-
tinguishing features of the 2, 10 and 50 foot depth lines, it can
be seen that one of the scale lines per track is darker than the
rest. This is accomplished by inserting the desired card into
the scale grid card reader 38 of Figure 1. The depth track is
shown in Figure 9 as being located between tracks 1 and 2 and
devoid of any printing other than the depth number. To ac-
complish this, the scale grid card reader generates a signal
designated "Depth Track Inhibit" (the means "NOT Depth
Track Inhibit") which is utilized by the combining and logic
circuit 42 to inhibit scale and depth lines from being printed
in the depth track (see Figure 1 ).
A depth number 11300 is printed in the depth track.
It can be seen that there is one digit of this number printed
every two feet for a ten foot interval. At 1304 and 1302 feet
"zeros" are printed and at 1300, 1298, and 1296 feet the
digits 311 are printed such that when examining the recording
10~7596
medium, it is evident that the heavy depth corresponds to a
depth of 11300 feet.
As discussed earlier, a trace is recorded on the
recording medium 25 by periodically sweeping the cathode ray
tube beam transversely across the recording medium and un-
blanking this beam at the proper time. If the well logging
signal to be recorded has a slow rate of change, the marks
will be placed on a recording medium in relatively closely
spaced apart positions. If the signal to be recorded has a
fast rate of change, these marks will be placed on a recording
medium at relatively widely spaced apart positions. This
difference is undesirable since it presents a non-uniform log.
To alleviate this problem each pulse position and pulse
width modulators 23 individually operate to vary the width
of the trace recorded on the recording medium in accordance
with the rate of change of the signal to be recorded.
To this end, referring to Figure 10, there is shown
one of the pulse position and pulse width modulators. In
actuality there are as many modulators as there are signal
2~ channels but since all such modulators are indentical, it is
only necessary to show one here. In Figure 10, the channel
signal from one of the low pass filters 22 (in this case, the
channel n signal is used) is applied to a voltage comparator
140 where it is compared in amplitudewith the sweep signal
from the sweep circuit 24. When the amplitude of the sweep
signal exceeds the channel n signal amplitude, the voltage
comparator 140 changes from the "zero" to "one" state.
The channel n signal is also applied to a second
voltage comparator 141 after being delayed by a delay circuit
142. The voltage comparator 141 also compares the channel
signal with the sweep signal to generate a "one" upon the
sweep signal amplitude exceeding the channel signal amplitude.
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i~47596
The outputs of both voltage comparators 140 and 141
are applied to the input of an Exclusive OR gate 143 which
changes from the "zero" to "one" state when one,'but not both,
outputs of the voltage comparators 140 and 141 are at the "one"
level. The leading edge of the resulting output pulse from
the Exclusive OR gate 143 energizes a one-shot 144 and the
output pulses from the exclusive OR gate 143 and one-shot 144
are ORed together in an OR gate 145 to produce the "writing
signal" for application to the line coding circuit 45 (see
Figure 1). The output signals from the voltage comparators
140 and 141 are also ORed together in an OR gate 146 for
application to the area coding card reader 47 for purposes
to be explained later.
Concerning the operation of the Figure 10 modulator
and referring to Figures llA-llE, Figure llA shows the sweep
position signal and delayed and undelayed channel signals, the
delayed channel signal being shown in dashed line form.
Figure llB shows the output pulses from the exclusive OR gate
143 and Figure llD shows the output pulses from the OR gate
145. The resulting recording trace is shown in Figure llE.
By comparison of Figures llA and llB it can be seen
that the pulse width of the output pulses from the Exclusive
OR gate 143 will vary as a function of the rate of change of
the channel signal to be recorded. Thus, as illustrated by the
left-hand portion of Figures llA and llB,' these pulse widths
will be extremely narrow when the input channel signal does
not vary in amplitude.
As seen by the intermediate portion of Figure llA,
when the channel signal begins to change in amplitude, the
delayed channel signal will have the same change but at a
delayed time. This causes the sweep signal to define'a given
time interval between the delayed and undelayed channel
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~047596
signals which defines the pulse width of the pulses of Figure 11B.
At the right-hand side of Figure llA, the input channel signal
changes amplitude very rapidly, thus causing the sweep signal to
define a long time interval between the time when the sweep
signal amplitude equals the channel signal to the time when it
eguals the delay channel signal.
Thus, it can be seen that the faster the rate of
change of the channel signal, the longer will be the duration
of the output pulse from the Exclusive OR gate 143. The one
shot 144 acts to guarantee a minimum pulse width for the
modulator output pulses such that minimum pulse width pulses
will be generated when DC signals are being recorded. The
combined output pulses from the exclusive OR gate 143 and one-
shot 144 are shown in Figure llD and produce the recording
traces of Figure llE.
Referring to Figure 12, there is shown an example
of a recording made using the modulator of Figure 10. During
the period when the channel signal does not vary in amplitude,
it can be seen from Figure 12 that dots will be recorded on
the recording medium. However, when the amplitude of the
signal begins changing, the transverse sweep lengths become
longer, thus compensating for the increase in the rate of change
of the input channel signal. The overall result is to produce
a recording which is uniform in appearance regardless of the
rate of change of the input channel signal.
Now, referring to Figure 13 there is shown one of the
parallel line coding circuits 45 of Figure 1 in detail. Since
all of the line coding circuits are identical, it is only nec-
essary to show one circuit in detail. The function of the line
coding circuits is to code the line which is recorded on the
recording medium 36 to thereby enable easy identification of each
of the various signals being recorded. Each line coding circuit
-34-
1047S~
receives an instruction from the line coding card reader 46 to
produce a dotted, dashed, long dashed, or solid line on the
recording medium.
One way of accomplishing this is to register a count
fDr each sweep of the CRT beam and alternately blank and
unblank the writing operation for a specified number of sùch
sweep counts to produce the desired code. To this end, the
sweep reset pulses from the sweep circuit 24 of Figure 1 are
applied to an OR gate 150 which, after processing by some
logic circuits, are applied to a divider made up of a divide
by five counter lSl and a divide by eight counter 152.
To this end, the sweep reset pulses from the sweep
circuit 24 of Figure 1 are applied to an OR gate 150 which,
after processing by some logic circuits, are applied to a
divider made up of a divide by five counter 151 and a divide
by eight counter 152. The feedback connections for the counters
151 and 152 are selectable to produce the desired line coding
pattern. Thus, for example, a mark could be recorded for 40
sweeps and inhibited for 40 sweeps, or recorded for 160 sweeps
and inhibited for 40 sweeps, etc. To perform the recording and
inhibit function, the normal output of the last stage of the
divide by eight counter 152 enables an AND gate 158 to pass the
writing signal from the appropriate one of modulators 23 to
the combining and logic circuit 42.
As discussed earlier, the length of the dots or
dashes will be dependent on the rate of change of the channel
signal to be recorded. In other words, if a dotting pattern
is desired where marks are inhibited from being placed on the
recording medium for 40 sweeps and then recorded for 40 sweeps,
it can be seen that 40 sweeps for a DC signal will produce a
much shorter line on the recording medi~m than 40 sweeps for
a rapidly varying signal.
~0475~6
To provide a uniform line coding pattern regardless
of the rate of change of the input channel signal, the writing
s:ignal from the proper modulator 23 enables an AND gate 153
which, when enabled, passes high frequency clock pulses from a
clock source 154 to the other input of the OR gate 150. Thus,
when the channel signal has a high rate of change, more pulses
are applied to the counters 151 and 152 than for the case of a
slowly varying signal. The frequency of the clock source 154 is
chosen in accordance with the CRT beam sweep rate to produce
the desired results.
Now, concerning how each of the individual line coding
patterns are produced and first concerning the dotting pattern,
the output pulses from OR gate 150 are applied to one input of
an AND gate 155 and one input of an AND gate 156. The normal
output of the last stage of the divide by eight counter 152 and
the dotting control signal from the line coding card reader 46
enable the AND gate 156 to pass the pulses from the OR gate 150
to the count input of the divide by five counter 151 via or OR
gate 157. Thus, when the line coding circuit is in the dotting
mode and the normal output of the last stage of the counter 152
is at the "one" level, the counters 151 and 152 will, in con-
junction, proceed to count 40 pulses from the OR gate 150. At
the end of 40 pulses, the last stage of the counter 152 changes
to its complementary state, thus disabling the output AND gate
158 and enabling the AND gate 155 to apply pulses to the input
of the counter 151 via the OR gate 157. After 40 more pulses
have been counted, the normal output of the last stage of counter
152 returns to the "one" state, thus enabling the AND gate 158
to pass writing signals to the combining and logic circuits 42
of Figure 1 and enabling the AND gate 160 again. The process
then repeats itself.
Thus, it can be seen that the line coding circuit of
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1047596
Figure 13 will inhibit at least a selected portion of one writing
signal from passing to the combining and logic c~rcuits 42. As
a maximum, it could inhibit many writing signals. The criteria
for inhibiting the writing signals or portions thereof is not the
nlLmber of writing signals themselves but the length of the line
being recorded on recording medium 36. This length is a function
of the pulse width of the writing signals from modulator 23.
Thus, the AND gate 153 will gate a quantity of clock pulses to
the counters 151 and 152 per sweep depending on the rate of
change of the channel signal. The application of the sweep reset
signal to the OR gate 150 for counting by counters 151 and 152
serves to set a minimum limit of one count per sweep when a DC
signal is being recorded. Looking at the extremes, if the
channel signal has a low rate of change, a great many writing
signals would be inhibited and if it has a high rate of change,
a portion of one writing signal would be inhibited or if the
rate of change is very high, sevexal non-adjacent portions of
one writing signal could be inhibited.
The dashing and long dashing operations are very
similar to the dotting operation except that the waveform
generated by the counter 152 will be unsymmetrical. This
unsymmetrical waveform is produced by inserting a divide by
four counter 159 in the feedback path from the normal output
of the last stage of counter 152 to the input of the counters
151 and 152. Thus, during a dashing operation, an AND gate
160 is enabled such that when the normal output of the last
stage of counter 152 goes to the "one" level, the pulses from
OR gate 150 will be applied to the divide hy four counter 159.
By so doing, the absence of a recorded trace will be 1/4 the
length of the recorded traces on the record medium 36. To
provide a long dashing operation, a divide by eight counter
161 is inserted in the feedback path. Thus, during such a long
~047S96
dashing operation, an AND gate 162 is enabled such that when
the normal output of the counter 152 is at the "one" level,
counters 161, 151 and 152 operate in a serial fashion to count
pulses from the OR gate 150. This arrangement dictates that
the recorded traces will be eight times as long as the absence
of such traces thus giving a long dash line.
To produce a solid line on the recorded medium 36,
a control signal designated "solid" from the 'iine coding card
reader 46 sets the last stage of the counte~ 152 to its nor~al
state such that the AND gate 158 is always enabled to pass
writing signals.
Now referring to Figure 14, there is shown the area
coding circuit 48 of Figure 1 in greater detail. The area
coding circuits of Figure 14 are made up of twelve individual
pattern generators which are utilized to generate the patterns
shown in Figures 15A-15L. As discussed earlier, these coding
patterns are generated whenever a selected channel signal
assumes a predetermined relationship to a second channel signal.
The area coding card reader 47 selects certain ones of the
pulses generated by the OR gate 146 (see Figure 10) of each
modulator of the parallel position and pulse width modulators
23 as "start" signals (start coding) and certain ones as "stop"
signals. The area coding card reader 47 also selects certain
ones of the divided clock signals from the binary counter 31
for application to the area coding circuits. In Figure 14,
these signals are designated SC2, SC4, SC8, etc., with the
number following "SC" indicating the stage of the counter 31,
i.e., SC2 indicates that the second stage of the counter 31 has
been selected.
The first circuit to be described will produce the
area coding pattern shown in Figure 15A. This pattern usually
designates oil. In Figure 14, a divide by four counter 171
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counts the trailing or rising edg~es of inverted sweep reset
pulses, designated SR, produced by inverting the sweep reset
pulses from the sweep circuit 24 of Figure 1. The falling
edges of the square wave output signal from the divide by
four flip-flop 171 and the inverted sweep reset pulses SR from
the AND gate 172 energize the set and reset inputs respectively
of a flip-flop 173. The rising edges of the output signal
from the nor~al output contact of the flip-flop 173 toggle a
flip-flop 174 which, when the normal output of flip-flop 173
is at the "one" level, enable a pair of AND gates 175 and 176
respectively to pass the sweep counter signals SC2 and SC2
respectively to a "trace length one-shot" 177. The pulse width
of the pulse generated by the one-shot 177 is set such as to
produce the desired trace length on the recording medium, i.e.,
it determines the unblanking time of the cathode ray tube 25.
To insure that the oil coding pattern is printed only
when one selected channel signal has a predetermined relation-
ship with the other selected channel signal, the trace length
pulses from one shot 177 are combined in an AND gate 178 with
the start and stop signals from the area coding card reader 47.
The card reader 47 provides for inversion of the stop signals.
The card reader 47 selects those area coding control
signals which are utilized as the start and stop signals for
each of the pattern generators of Figure 14. Thus, for example,
if the oil coding pattern generated by the circuit 170 is to be
printed on a recording medium whenever the channel 2 signal is
~ greater in amplitude than the channel 4 signal, the card reader
47 will select the channel 4 signal as the stop signal and apply
these to the oil coding circuit 170. To insure that no scale
and depth lines are recorded while the area coding pattern is
being recorded, the start and stop signals from the area coding
card reader 47 are combined in an AND gate 179 to produce a
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control signal representative of the time interval during which
the area coding pattern is being generated. This area coding
blanking signal is applied to the combining and logic circuit 42,
which as will be discussed later, blanks out depth and scale
lines while the area coding pattern is being recorded.
To better understand how this conditional area coding
operation takes place, refer to the oil coding circuit 17 of
Figure 14 in conjunction with Figures 16A-16F. Figure 16A is
an illustration of the sweep signal overlayed on the channel
signals which are selected by the area coding card reader 47
as the start and stop signals for use by the area coding cir~
cuits. Figure 16B shows the sweep reset pulses generated by
the sweep circuit 24 of Figure 1.
It will be recalled from the discussion of the
modulator of Figure 10 that the output of the OR gate 146 will
rise to the "one" level upon the sweep voltage exceeding the
channel signal amplitude and will remain at that level until
the sweep signal amplitude is less than the channel signal
amplitude. Thus the area coding control signal generated by
the modulator which is processing the signal designated
"start" in Figure 16A will produce the area coding control
signal of Figure 16C. Likewise, the modulator which is pro-
cessing the channel signal designated "stop" in Figure 16A
will produce an inverted version of the area coding control
signal shown in Figure 16D. (The stop signal is illustrated
in Figure 16D.) Through action of the area coding card reader
47, the signal in Figure 16C becomes the start signal and the
control signal of Figure 16D becomes the stop signal which
are applied to the AND gates 178 and 179.
The conjunctive function, start-stop is shown in
Figure 16E and, through the action of AND gate 179, comprises
the area coding blanking signal. Likewise, through the action
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of AND gate 178, start and stop enables the area coding signal
pulses from the trace length one-shot, shown in Figure 16F, to
be applied to the combining and logic circuit 42 as the area
coding writing signal whenever the normal output of the flip-
flop 173, shown in Figure 16G, is at the "one" level. Since
the flip-flop 173 is set only once every four sweeps, after the
sweep reset pulse 180 of Figure 16B resets flip-flop 173 (see
Figure 16G), this flip-flop will remain in a reset state for
the next four sweeps. Then it will be set by the fourth reset
sweep pulse after pulse 180 to allow the area coding signal of
Figure 16F to be passed.
It can, therefore, be seen that the oil coding circuit
170 will operate to produce evenly spaced dots on the recording
medium 36 for one out of every four sweePs,in the area bounded
by the logs selected by the area coding card reader as the start
and stop logs. The space between each dot in the direction of the
.. . . . ... . _ , . .. .. . .
sweeping beam (transverse to the record medium 36) will be deter-
mined by the counter signal SC2. The toggle FF 174 changes state,
every fourth sweep, and alternate,,,ly en,ables gates lZ5 an~ ll6, thus
; 20 alternately connecting SC2 and SC2 counter signals to the one-shot
177. This staggers the dots printed on alternate lin~s of dots.
' Now, concerning the circuit for producing a coding
pattern which designates "gas", refer to the "gas coding circuit"
182 of Figure 14. This gas coding circuit 182 operates in a
manner very similar to the oil coding circuit 170 except that
only one sweep out of eight is utilized to produce dots on the
- recording mediums and these dots are spaced twice as far apart
as those for the oil coding circuit 170.
The major portion of the gas coding circuit 182 is
the logic circuit A portion of the oil coding circuit 170. In
circuit 170, this logic circuit A comprises all of the oil coding
circuit 170 except the divide by four circuit 171 and is that
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1(~47596
portion of the oil coding circuitry enclosed by the dashed
lines.
To produce the recording of dots once every eight
sweeps, the square wave output signal from the divide by four
flip-flop 171 of circuit 170 is applied to a divide by two
flip-flop 183. The output of the divide by two flip-flops
183 is thus equal to SR/8 and is applied to the set input of
the corresponding flip-flop 173 within the logic circuit A of
the gas coding circuit 182. To produce the wider spacing of
dots during those sweeps when dots are recorded, the SC4 and
SC4 signals from the binary counter 31 of Figure 1 are applied
to AND gates within the logic circuit A of the gas coding
circuit 182 which correspond with the AND gates 175 and 176 of
the oil coding circuit 170. The resulting pattern produced
on the recording medium is illustrated in Figure 15B.
Looking now at Figure 15C, there is shown the area
; coding pattern used to designate "sand". It can be seen that
the dots recorded for this pattern are further spaced apart
than the dots for the pattern shown in either Figures 15A or
15B. Returning to Figure 14, the "sand logic circuit" 185
acts to produce this coding pattern of Figure 15C. The sand
logic circuit includes the logic circuit A discussed earlier.
To produce the wider spaced dots, the SR/8 square wave signal
from the flip-flop 183 is applied to a divide by two flip-flop
186 within the sand logic circuit 185 so that the dots will be
recorded only once everysixteen sweeps. Moreover, the SC8 and
SC8 signals from the binary counter 31 of Figure 1 are applied
to the AND gates of the sand logic circuits 185 which correspond
to the AND gates 175 and 176 of the logic circuits A of the oil
coding circuit 170.
The next pattern generator to be discussed will pro-
duce the coding pattern seen in Figure 15D. This Figure 15D
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pattern comprises alternate light and dark stripes which run
transversely of the record medium. This Figure 15D pattern
designates "movable oil". To produce this pattern is the
function of the "movable oil coding circuit" 190 of Figure 14.
The coding circuit 190 alternately passes and inhibits the
pulses generated by the trace length one-shot 177 of the oil
coding circuit 170 during alternate two foot sections on the
recording medium 36.
To accomplish this, the output pulses from the trace
length one-shot 177 of circuit 170 are applied to an AND gate
191 within the movable oil coding circuit 190. The start and
; stop signals from the area coding card reader 47 enable the
AND gate 191 when the conditional coding format is satisfied.
To provide the alternate recording and inhibiting of the pulses
generated by the trace length one-shot 177 during successive
two foot sections, the two foot sweep signal from the depth
interval detector 63 and the sweep control signal from sweep
circuit 24 of Figure 1 are combined in an AND gate 192 and the
trailing edge of the resulting output pulses from AND gate 192
trigger a toggle flip-flop 193 whose normal output enables the
AND gate 191. By this arrangement, the flip-flop 193 will
enable the AND gate 191 once every other two foot section to
produce the pattern indicated in Figure 15D.
The start and stop signals are combined in an AND
gate 194 whose output signal is the area coding blanking signal
which is applied to the combining and logic circuits 42 to blank
out the writing of scale and depth lines when the movable oil
coding pattern is being recorded.
The next pattern generator to be described produces
area coding pattern shown in Figure 15E. It can be seen that
this area coding pattern is similar to the one shown in Figure
15D except that the dotting pattern produced for the dark
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sections is more wiael~ dispersed, thus giving a lighter or
greyish appearance to the dark sections thereof. This pattern
of Figure 15E designates "movable gas" and is generated by the
"movable gas coding circuit" 196 in Figure 14.
The movable gas coding circuit 196 includes a toggle
flip-flop 193A which is toggled by the output pulses from the
AND gate 192. An AND gate l91A is responsive to the start and
stop signals selected by the area coding card reader for the
movable gas coding circuit 196 and the normal output of the
flip-flop 193A for passing the trace length pulses produced by
logic circuit A of the gas coding circuit 182. These passed
or gated SR/8 pulses constitute the area coding writing signal
from the movable gas coding circuit 196. An AND gate 194A
responds to the start and stop signals selected by the card
reader for the movable gas circuit 196 to generate the area
coding blanking signal for coding circuit 196.
The difference between the movable gas coding circuit
196 and the movable oil coding circuit 190 is that in the former,
the AND gate l91A is responsive to the pulses generated by the
trace length one-shot (corresponding to one-shop 177 of coding
circuit 170) within logic circuit A of the gas coding circuit
182 while the latter uses the trace length pulses from one-shot
177. Thus, the oil pattern of Figure 15A will make up the dark
areas of the movable oil pattern of Figure 15D while the gas
pattern of Figure 15B will make up the dark areas of the Figure
15E movable gas pattern. Since the oil dotting pattern of Figure
15A is denser and thus darker in appearance than that for the gas
coding pattern of Figure 15B, the dark sections of Figure 15E
will appear lighter than those of Figure 15D.
The next pattern generator to be described produces
the coding pattern shown in Figure 15F. This coding pattern
comprises the absence of all marks in the area for which coding
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is desired and represents porosity. To produce this pattern
:is the function of the porosity coding circuit 198 of Figure
14. The porosity coding circuit 198 through an AND gate 199
merely responds to the stop and start signals selected by the
area coding card reader 47 for the porosity coding circuit to
prevent the writing of all data between the start and stop
logs. The output signal from AND gate 199 constitutes the
area coding blanking signal for the coding circuit 198.
The next pattern generator to be described produces
the coding pattern of Figure 15G, which is the coding pattern
for "water". This coding pattern comprises a light area be-
tween the start and stop logs, broken only by the presence of
scale lines. To provide this coding pattern, a "water coding
circuit" 200 of Figure 14 includes an AND gate 201 which is
responsive to the start and stop signals from the card reader
47 for this circuit for generating the area coding blanking
signal which inhibits the writing of data in the area bounded
by the start and stop logs. Then, to produce the scale lines,
the scale line signal from the OR gate 41 of scale line cir-
cuit 37 of Figure 1 is applied to an AND gate 202 which is also
responsive to the start and stop signals for producing the area
coding writing signal for the water coding circuit. Thus, the
AND gate 202 reinserts the scale line signals which have been
inhibited by the action of the AND gate 201.
The next pattern generator to be described produces
the coding pattern of Figure 15H which is the pattern for a
type of shale which, for present purposes, if designated shale
No. 1. As seen in Figure 15H, this coding pattern is defined
by vertically spaced apart dashed lines wherein the dashes are
staggered from one depth level (transverse or vertical lines on
the record medium) to the next and is generated by the shale
No~ 1 coding circuit 205 of Figure 14.
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Within the coding circuit 205, a flip-flop 206 is set
by the SR/16 pulses and reset by the SR pulses. The rising
edge of the normal output of flip-flop 206 toggles a toggle
flip-flop 207 whose normal and complementary outputs enable a
pair of AND gates 208 and 209 respectively to pass the sweep
counter 31 square wave signals SC16 and SC16 respectively. The
outputs of both AND gates 208 and 209 energize a trace length
one-shot 210 which generates a pulse whose duration is selected
to produce a trace length corresponding to those shown in Figure
15H. The output pulses from the trace length one-shot 210,
along with the start and stop signals selected by the area
coding card reader 47 for this coding circuit are combined in
an AND gate 211. The resulting output signal from AND gate 211
constitutes the area coding writing signal for the shale No. 1
coding circuit 205. An AND gate 212 is responsive to the start
and stop signals selected for this coding circuit for producing
the area coding blanking signals.
It can be seen that the flip-flop 206 will be set
once every sixteen sweeps to thereby cause the energization of
the trace length one-shot 210 once per 16 sweeps. The vertical
or transverse distance between the initiation of each trace
written on the recording medium is set by the SC16 a~d SC16
counter signals. By way of comparison, this distance for the
shale No. 1 pattern is eight times greater than that for the
oil pattern of Figure 15A since the counter signals SC2 and SC2
are used by the oil coding circuit 170. It can be seen that
every othertime the flip-flop 206 is in its normal state, one or
the other of the AND gates 208 and 209 will be enabled to pass
the SC16 and SC16 signals respectiv~ly thus causing the traces
to be staggered on the recording medium 36.
The next pattern generator to be described will pro-
duce the coding pattern shown in Figure 15I which corresponds to
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a second type of shale, designated "shale No. 2". As seen in
Figure 15I, this coding pattern is similar to the coding pat-
tern of Figure 15H except that the vertica~Y directed dashes
are longer and further spaced apart. This coding pattern is
13enera*edby the shale No. 2 coding circuit 215 of Figure 14.
To produce this pattern, the coding circuit 215 uses the normal
output of the flip-flop 207 of the coding circuit 205 to en-
able a pair of AND gates 216 and 217 which are also responsive
to the sweep counter signals SC32 and SC32 respectively. The
output pulses from AND gates 216 and 217 energize a trace length
one-shot 218. An AND gate 211 passes these trace length pulses
as the area coding writing signal for coding circuit 215 when
the start and stop signals selected for this circuit 215 are
both at the "one" level. As before, an AND gate 221 responds
to the start and stop signals selected for circuit 215 to pro-
duce the area coding blanking signal for this circuit.
Since the normal output of the flip-flop 2Q7 will be
one-half the frequency of the flip-flop 206 output signal, the
sweeps for which traces are recorded will be twice as far apart
as for the shale No. 1 coding pattern. Likewise, since the SC32
and SC32 counter signals are used instead of SC16 and SCl-6-, the
trace length one-shot 218 of the shale No. 2 coding circuit 215
- is energized one-half as often as for the shale No. 1 coding
circuit 205. The trace length one-shot 218 has a timing circuit
set to produce pulses having a pulse width greater than that for
the trace length one-shot 210 of coding circuit 205 to produce
longer length dashes on the record medium 36. To provide for
staggering the dashes on alternate writing sweeps, the AND gates
216 and 217 are alternately enabled by the flip-flop 219 to pass
the counter signals SC32 and SC32 on alternate writing sweeps.
The next pattern generator to be described will pro-
duce the coding pattern of Figure 15J which designates limestone.
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This coding pattern is made up of a plurality of spaced vertical
lines having interconnecting horizontal lines between each pair
of vertical lines, which horizontal lines are vertically stag-
gered from one pair of vertical lines to the next. The circuit
for generating this pattern is the limestone coding circuit 225
of Figure 14.
To produce the spaced apart vertical lines, and AND
gate 226 is responsive to the coincidence of the two foot sweep
signal and sweep control signal from the AND gate 192 and the
start and stop signals selected by the area coding card reader
47 for this coding circuit 225 to produce a vertical (transverse
to the record medium) line once every two feet. To produce the
staggered horizontal lines, the rising edges of the two foot
sweep control signal from AND gate 192 toggles a divide by two
flip-flop 227 whose normal and complementary outputs enable a
pair of AND gates 228 and 229 respectively. When enabled, the
AND gates 228 and 229 pass the sweep counter signals SC32 and
SC32 to energize a trace length one-shot 230. The time period
of the pulses generated by the one-shot 230 are small so as to
produce dots on the recording medium. The output pulses from
the trace length one-shot 230 are then combined in an AND gate
227 with the start and stop signals selected for this coding
circuit so as to produce writing signals which will produce the
staggered horizontal line shown in Figure 15J.
The output signals from AND gates 226 and 227 are
then combined to produce the area coding writing signal for the
limestone coding circuit 225 to produce the pattern of Figure 15J.
As before, the area coding blanking signal is produced by com-
bining the start and stop signals in an AND gate 228.
Summarizing the operation of this limestone coding
circuit 225, the AND gate 225 operates to produce the vertical
lines shown in Figure 15J. ~In actuality, the area coding
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blanking signal produced by the AND gate 228 inhibits the
writing of depth line between the start and stop logs and the
AND gate 226 merely reinserts the two foot depth lines in this
area.) To produce the horizontal lines, the edge of one of the
SC32 and SC32 square wave counter signals periodically energizes
the trace length one shot 230 to produce dots on-the recording
medium at the same vertical position during each sweep. Thus,
during a succession of sweeps, a horizontal line will be pro-
duced. Then, when the next two foot depth line is reinserted
by the AND gate 226 in the area normally set aside for area
coding, the two foot sweep control signal from AND gate 192
which causes this depth line to be reinserted also toggles the
divide by two flip-flop 227 to reverse the enable-disable
configuration AND gates 228 and 229 and thus of SC32 and SC32.
By so doing, the staggering of the horizontal lines between
vertical line pairs is produced.
The next pattern generator to be described produces
the area coding pattern of Figure 15K, which represents dolomite.
As seen in Figure 15K, this pattern is very similar to the
limestone coding pattern of Figure 15J except that the hori-
zontal lines for limestone are slanted for dolomite. To produce
this coding pattern is the function of the dolomite coding cir-
cuit 235 of Figure 14.
The reinsertion of the two foot depth line is produced
in this circuit 235 by an AND gate 236 which is responsive to
the coincidence of the two foot sweep signal and the sweep
control signal, and the start and stop signals selected by the
area coding card reader 47 for this coding circuit. This is
essentially the same function as was performed by AND 226 of
the limestone coding circuit 225. To produce the slanted lines
between the two foot vertical lines, the rising edges of the
s~uare wave output signals produced by either of the AND gates
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~047596
228 or 229 of the limestone coding circuit 225 set a flip-flop
237. When the flip-flop 237 is set, an AND gate 238 is enabled
to pass the clock pulses designated CL from the sweep circuit
24 of Figure 1 to the count input of a down counter 239 ("down
counter" signifies that this counter 239 subtracts a count for
each pulse supplied thereto). When the contents of the down
counter 239 have been completely subtracted away, the leading
edge of the resulting borrow pulse resets the flip-flop 237.
When the flip-flop 237 is reset, a trace length one-shot 240
generates a short time duration pulse which, during the
coincidence of the start and stop signals selected by the area
coding card reader 47 for this coding circuit, is passed by an
AND gate 241 as part of the area coding writing signal for this
coding circuit. The outputs of AND gates 236 and 241 comprise
the area coding writing signal for the dolomite coding circuits.
What has been described thus far in the dolomite coding
circuit 235 would produce the limestone pattern of Figure 15G
given by the limestone coding circuit 225, i.e., the lines be-
tween the vertically extending two foot depth line would be
horizontal. To provide for slanting lines, a binary counter
242 is advanced one count for each sweep reset signal applied
to its count input, i.e., it is advanced one count per sweep.
The leading eage of the sweep reset pulses causes the counter
242 to advance. The contents of the binary counter 242 are
transferred to the down counter 239 in response to the trailing
edges of the pulse from the one-shot 240. Thus, for each sweep
of the CRT beam, the number placed in the down counter 239 in-
creases by one count thus causing the down counter 239 to receive
one more CL pulse per sweep for the contents thereof to be
emptied. Consequently, it takes a slightly greater time for
each additional sweep for the trace length one shot 24~ to be
energized thus producing a slanted line.
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At every two foot depth interval, the binary counter
242 is reset by the two foot sweep control signal from AND gate
192 to initiate the production of the slanted line between the
next pair of two foot depth lines. Since the two foot sweep
control signal toggles the flip-flop 227 for alternately en-
abling AND gate 228 and AND gate 229, the slanted lines will
be staggered because of the alternate selection of the SC32 and
SC32 counter signals by the AND gates 228 and 229.
The area coding blanking signal is produced by an
AND gate 243 in response to the start and stop signals in the
usual manner.
The last pattern generator to be described produces
the coding pattern of Figure 15L which identifies anhydrite and
is produced by the anhydrite coding circuit 245. This coding
pattern is a slanted line pattern within the area bounded by the
start and stop logs selected by the card reader 47. To produce
this pattern a divide by 40 counter 247 counts both the clock
pulses CL from the high frequency clock 29 of Figure 1 and the
sweep reset pulses from the sweep circuit 24 of Figure 1, which
are combined in an OR gate 246. An edge of the square wave out-
put signal from the counter 247 energizes a trace length one-shot
248 which generates pulses having a short time duration so as to
produce dots on a recording medium. These pulses generated by
the one-shot 248 are combined in an AND gate 249 with the start
and stop signals so that the coding pattern will be produced
only between the selected start and stop logs. The start and
stop signals are also combined in an AND gate 250 to produce the
area coding blanking signal in the same manner as discussed
previously.
Neglecting for the moment the effect of the sweep re-
set pulses, the clock pulses would, after division by the divide
by forty counter 247, cause a dot to be placed on the recording
~04759~i
medium at the same Yertical (or transverse) position for each
sweep, thus producing a plurality of horizontal lines spaced
apart a distance corresponding to CL/40. However, since the
sweep reset pulses are also counted by the counter 257, the net
effect is to move the vertical point at which the dot is re-
corded for each sweep a given vertical increment. Thus, since
the recorded dot is moved a given vertical increment for each
sweep, the net result is to produce slanted lines within the
area defined by the start and stop logs.
Now, referring to Figure 17, there is shown the
combining and logic circuit 42 and the CRT brightness control
circuits 50 of Figure 1 in greater detail. First, concerning
the combining and logic circuit 42, it is the function of this
circuit to combine the writing signals from the parallel line
coding circuits 45, the area coding circuit 48, as well as the
trace intensified writing signals from card reader 49, and the
scale and depth line signals from the scale line circuit 37 and
depth line generator 64 for application to the CRT 25. In
addition to these combining operations, circuit 42 also performs
certain logic operations to give a desired recording format.
The line coded writing signals from the line coding
circuits 45 of Figure 1 are combined in an OR gate 260 and the
area coding writing signals from the area coding circuits 48
are combined in an OR gate 261. The outputs of OR gates 260
and 261 are combined in OR gate 262 for application to one in-
put of an AND gate 263.
As discussed earlier, no data is to be written on the
recording medium while the initial scale line is being printed
and during the fly-back of the cathode ray tube beam, i.e.,
during sweep reset. Therefore, the initial scale line and sweep
reset pulses, after inversion by a pair of NAND gates 264 and
265, respectively, are applied to individual inputs of the AND
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gate 263 so as to inhibit any writing signals from OR gate 262
during printing of the initial scale line and fly-back of the
cathode ray tube beam. The output of the AND gate 263 is
applied to a limiter circuit 266 which sets the desired voltage
level for the output signals from AND gate 263 and then applies
the signals to the CRT brightness control circuit 50.
.. . . . . . ................ . . . . . .. . .
The scale and depth lines are combined in an OR gate
267 for application to a limiter circuit 268 which performs the
same function as limiter circuit 266 and then applies the scale
and depth line signals to the CRT brightness control circuit 50
To insure that a depth line signal is generated only during the
time the beam is being swept across the usable portion of the
recording medium, the depth line signal and sweep control sig-
nal are combined in an AND gate 269 before being applied to the
OR gate 267. Moreover, since as discussed earlier, scale and
depth lines are not to be written in the depth track, the depth
track inhibit signal from the scale grid card reader 38 (see
Figure 1) is used to disable the AND gate 269 and an AND gate
270 to which the scale line signals are applied whenever the
CRT beam is being swept through the depth track. Also depth
and scale lines are not to be recorded whenever one of the area
coding pattern generators is operating to produce a pattern
(except where the pattern generator itself reinserts the depth
or scale line) or when a channel signal is being recorded. To
accomplish this function, the area coding blanking signals from
the area coding circuits 48 are combined in an OR gate 271 and
the output of this OR gate is combined with the output of AND
gate 263 in an OR gate 272. The output signal from the OR gate
272 thus represents the combination of the area coding blanking
signal and the line and area coding writing signals. Since
scale and depth lines are not to be recorded when any of these
other signals are processed for recording, the output control
lQ47596
signal from OR gate 272 is inverted by a NAND gate 273 and
applied to the input of an AND gate 274, to which also is
supplied the output from OR gate 267. Thus, the AND gate 274
will be disabled whenever the channel signals are being recorded
and during area coding.
In addition to the above, the combining and logic
circuit ~2 also combines the trace intensifier signals from the
.. ..
trace intensifier card reader 49 of Figure 1 in an OR gate 275,
and the amplitudes of the signals from OR gate 275 are limited
by a limiter circuit 276 before application to the CRT bright-
ness control circuit 50. The amplitude level of the limiter
circuit 276 is set high enough to enable a higher amplitude
level for these trace intensified output signals from OR gate
275 than the scale and line signals from gates 267 and 274 and
the line and area coded writing signals from AND gate 263.
Now, concerning the CRT brightness control circuit
portion of Figure 17, the line and area coded writing signals,
scale and depth line signals, and trace intensifier signals
from the limiter circuits 266, 268, and 276 respectively of
the combining and logic circuit 42 are fed to the negative or
inverting input of an operational amplifier 280 via summing
and weighting resistors 281, 282, and 283 respectively. The
; values of these resistors 281, 282 and 283 are set in con-
junction with the limiting values of the limiter circuits 266,
268 and 276 to bring about the proper relationship of trace
intensities for the coded writing signals, scale and depth line
signals, and trace intensifier signals. These combined signals
are then further processed by the CRT brightness control circuits
50 for use in unblanking the CRT beam.
With a CRT having a fiber optic faceplate, the anode
must be operated at ground potential, thus necessitating that
the grid and cathode be at a high negative potential, e.g.,
1~347596
approximately -10,000 volts. Since the signals of the opera-
tional amplifier 280 are within a few volts of ground potential,
these signals must be translated through a level of thousands
of volts. To alleviate this problem, a transformer 284 isolates
the two circuits and the amplitude of a high frequency signal
produced by an oscillator 282 is controlled by the output signals
from amplifier 280. To this end, the amplifier 280 signals
control the gain of a variable gain amplifier 281 to which the
high frequency signal from oscillator 282 is applied. The out-
put signal from amplifier 281 feeds the primary winding 283 of
a transformer 284 with one side of the primary winding 283 being
connected to the same circuit ground as the amplifier 283. On
the secondary side of the transformer 284, the signals are
detected by the detector 285, i.e., converted to signals which
resemble the signals produced by the amplifier 280, and applied
to an amplifier and pulse shaper 286. This circuit 286 operates
to produce the final amplification to obtain the voltage level
necessary for the cathode ray tube 25 and shape the pulses in
a manner to compensate for the non-linear effects of the cathode
ray tube 25.
As discussed earlier, the beam intensity of a cathode
ray tube can vary during the operation of the tube. Of course,
such a variation in beam intensity would be undesirable for
present purposes because it would tend to vary the quality of
the recording. To alleviate this problem, a current to voltage
converter 287 monitors the beam current at the anode of the
cathode ray tube 25 and supplies a voltage proportional thereto
to the summing input of the amplifier 280 to thereby maintain
this beam current constant. However, since the beam current is
being modulated in accordance with the information to be recorded,
the beam current cannot be monitored indiscriminately because
of the wide fluctuation or variation in this modulation during
any given sweep.
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To provide a valid measure of beam current, a sample
and hold circuit 288 is responsive to the initial scale line
s,ignal from the scale line circuit 37 of Figure 1 for instruct-
ing the sample and hold circuit 288 to sample the voltage out-
put of the converter 287 only when the initial scale line is
being recorded. It will be recalled from the discussion of
Figure 1 that the initial scale line pulse was combined with
the other scale line pulses in the OR gate 41 for application
to the combining and logic circuit 42 as the "scale line sig-
nals". It will also be recalled from the discussion of the
combining and logic circuit 42 of Figure 17 that the initial
scale line pulse caused all other writing signals to be in-
hibited. Thus, it can safely be assumed that the output signal
from the amplifier 280 will always be of constant amplitude
while the initial scale is being recorded.
Since the sample and hold circuit 288 operates to
sample this beam current only when the initial scale line is
being recorded, the beam current can be measured once per
sweep and adjusted in response to this measurement to provide
the desired beam intensity throughout the remainder of the
sweep. To this end, the output signal from the sample and
hold circuit 288 is applied to a low pass filter 287 which
filters out transient occurring during this sampling process
and applies the measured beam current indication signal to a
suitable meter 2g0 and to the summing input of the amplifier
280 via a summing resistor 291. The time constant of the low
pass filter 289 can be selected high enough to prevent one or
two erroneous measurements from completely upsetting the
appearance of the recording, i.e., the feedback system will
only respond to relatively slow changes in beam current
intensity.
A "brightness adjust potentiometer" 292 also provides
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current to the summing input of the amplifier 280 via a summing
resistor 293. The position of the potentiometer 292 can be
preset to give the desired brightness level.
The recording system described up to this point
derives data from telemetry equipment for recording. It would
also be possible to record data while the exploring device
which makes the measurements is moved through the borehole.
This could be accomplished by recording the measurements
derived directly from the downhole exploring device or recording
this data after it has been digitized by a digital tape recorder.
First concerning the recording of data from a digital
tape recorder simultaneously with writing the well logging
measurements on magnetic tape, refer to Figure 18. In Figure
18, a well tool 300 is suspended in a borehole 301 by a multi-
conductor cable 302 for investigating the surrounding earth
formations 303. The measurement signals produced by the well
tool 300 are transmitted to suitable signal processing circuits
304 over the conductors of the cable 302. The signal processing
circuits operate to, for example, reference the signals to a
common reference potential and depth. The processed signals are
then applied to a digital tape recorder 305 which digitizes the
meausurements and writes them on magnetic tape. The tape
recorder 305 could comprise any digital tape recorder. One
example of a suitable tape recorder is disclosed in U.S. Patent
No. 3,457,544 granted to G. K. Miller et al on July 22, 1969.
This Miller et al tape recorder produces a plurality
of signals which are used by the recording equipment of the
- present invention. It produces a plurality of channel selection
signals 306 which designates the channel for which PCM data on
a conductor 307 corresponds to. It also generates shift pulses
for use by exterior equipment in shifting the PCM data into a
suitable entry register and a "shift pulse window" for use in
properly gating the shift pulses to insure that the proper
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number of shift pulses are used. Finally, it generates a "depth
word" signal whenever a depth word is on the PCM data line 307.
To produce the digital data words as a function of borehole
depth, a shaft 313 which is rotatably connected to a wheel 314
in rotatable engagement with the cable 302 is connected to the
input of the tape recorder 305. This shaft causes a circuit
within the tape recorder 305 to generate incremental depth
pulses at given depth increments which are used to initiate
the digitizing operation. For more information on this tape
recorder and how it produces these signals, refer to the Miller
et al Patent No. 3,457,544.
Now concerning how the digital data from the tape
recorder 305 is processed for application to the recording equip-
ment of Figure 1, the PCM data line 307 from the tape recorder
305 is connected to the inputs of a plurality of individual
storage registers 308. The particular register which the PC~
data is entered into is selected by the channel designation sig-
nals on conductors 306, i.e., one channel designation conductor
at a time will be active to thereby activate one storage register
at a time to enter the PCM data. The shift pulses and shift
pulse window signal from the tape recorder 305 are combined in
an AND gate 309 for application to each of the individual stor-
age registers 308. Thus, a particular storage register will be
selected by one of the channel designation signals and the PCM
data will be entered into this selected register under control
of the gated shift pulses.
The output stages of the storage registers 308 are
connected to digital to analog converters 309, the output stages
of each storage register 308 being connected to an individual
digital to analog converter. Thus, each converter 309 will
produce an analog output signal whose amplitude is proportional
to the digital ~umber contained in each storage register 308,
i.e., one analog signal per channel.
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As set forth in the Miller et al tape recorder patent
word 1 of each frame is reserved for the depth word. Since
there is no need to convert depth words into analog quantities,
the analog signals from converters 309 are sampled during the
time period when the depth word is being processed by the tape
recorder 305. To this end, the leading edge of the depth word
control signal from tape recorder 305 energizes a "strobe one-
shot" 310 which applies a strobe pulse to suitable sample and
hold circuits 311. When strobed, the sample and hold circuits
311 sample the analog voltages from the digital to analog
converters 309. The stored analog signals in sample and hold
circuits 311 are then applied to the filters 22 of Figure 1 in
place of the signals from the telemetry unit 20.
A plurality of bias circuits 312 operate to select-
ively bias the analog well logging signals to place them in
selected tracks on the recording medium. In the Figure 1 system,
it was assumed that this bias operation was taken care of prior
to processing of the data by the Figure 1 circuits, i.e., the
data output from the input equipment 20 already include the
proper bias. Of course, if desired, bias circuits could be
included in the Figure 1 apparatus (just after the low pass
filters 22) to perform this operation.
To supply the depth data to the Figure 1 recorder
circuits, the shift window, depth word designation signal and
shift pulses are all applied to the AND gate 91 of Figure 4 so
as to enable the PCM depth word to be entered into the entry
register 90. The depth word is then processed in the manner
discussed earlier to provide depth indications on the recording
medium.
In this case where the well logging measurements are
recorded while they are being made by the well tool 300, the
recording medium is driven by the shaft 313. In this case, also
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~or optimum results, the CRT beam sweep repetition rate should
not be at a constant frequency. Of course, for good recording
resolution, there should be plurality of sweeps between sampling
and digitizing of the well logging measurements. In the Miller
et al tape recording system, the depth word designation signal
is generated every time the well logging measurements are
sampled, for most applications. Thus, the strobe pulse from
the one-shot 310, which was energized by the depth word
designation signal, is applied to a sweep pulse generator 315.
The generator 315 generates a plurality of pulses per strobe
pulse which are applied to the set input of the sweep control
flip-flop 27. In this embodiment, the 120 Hertz pulse generator
26 would be disconnected.
The sweep pulse generator 315 could take the form of
a pulse generator which generates a fixed number of pulses when
energized. Each generated pulse would energize a recorder drive
stepping motor 316 which when energized, would cause the record-
ing medium to step a predetermined incremental distance. This
stepping of the recording medium is synchronized with the sweep
of the beam across the face of the cathode ray tube.
It is not necessary to use a digital tape recorder to
supply "real time" data to the recorder of the present invention.
Instead, the well logging measurements could be applied directly
to the present recorder. Turning to Figure 19, there is shown
such an arrangement. The well logging measurements from signal
processing circuits 304 are applied directly to parallel sample
and hold circuits 320. To strobe the circuits 320, a depth
pulse generator 321 generates a pulse each given incremental
movement of the shaft 313. These depth pulses also energize the
sweep pulse generator 322 which performs the same function as
the generator 315 of Figure 18.
To provide the depth information to the recording
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equipment of the present invention, the shaft 313 is connected
to a depth encoder 343 which can, if desired, take the form of
the depth encoder illustrated in the Miller et al tape recorder
patent. The digitized depth data is then transferred to the
depth determination circuits 60 of Figure 1. In this Figure
19 case, the data could be transferred in parallel to the
circuits 60 thus eliminating the necessity of shift pulses and
the shift pulse window.
It can thus be seen from the foregoing that new and
improved methods and apparatus have been provided for recording
well logging data. This has been accomplished by utilizing a
cathode ray tube for recording such signals. A recording system
has been shown and described which not only can record data as
it is being derived from a well logging tool in a borehole, but
can also record data being transmitted or received over a
telemetry link as well as data which has been previously recorded
on magnetic tape and then played back to the recorder. The
recorder of the present invention can provide any desired pattern
of scale and depth lines. Moreover, this recorder is able to
produce any number of line and area coding patterns as desired
to thereby enable easy identification of not only individual
logs recorded on the recording medium, but also parameters
represented by the areas between certain selected logs. This
coding can be conditional by allowing area coding only when
these logs maintain certain selected relationships to one an-
other. Moreover, good quality recordings can be obtained
regardless of the rate of change of the signals to be recorded.
It should be pointed out here that the techniques of
the present inventions could be used with other types of record-
ing devices than the fiberoptic CRT shown here. For example,
an electrostatic recorder could be used just as well. Such an
electrostatic recorder would have a plurality of wire ends
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positioned transversely across a record medium. The proper
wire end would be energized to produce a mark at the proper
position.
While there has been described what is at present
considered to be preferred emboaiments of this invention, it
will be obvious to those skilled in the art that various
changes and modifications may be made in the instrument without
departing from the invention, and it is, therefore, intended
to cover all such changes and modifications as fall within the
true spirit and scope of the invention.
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