GB2110907A - Well logging system and method - Google Patents

Abstract

The invention provides for the display on a cathode ray tube of well logging data. The logging measurements are preferably derived in or converted to digital form, and are thereafter applied to video circuits for graphic display as the measurements are derived in the borehole. The image is continually scrolled in correlation with movement of the sonde through the borehole whereby a visible representation of a preselected portion of the measurement may be continuously observed as it is obtained. <IMAGE>

Description

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SPECIFICATION

Well logging system and method

5 This invention relates to methods and apparatus for investigating the lithological characteristics of subsurface earth materials, and more particularly relates to improved methods and apparatus in which well logging data and information is visually display-10 ed.

ft is well known that petroleum substances are found in subsurface earth formations, and that boreholes are conventionally drilled into such formations for the purpose of recovering these 15 substances. What is not well known, however, is that it is conventional practice to survey the earth materials along the length of the borehol e, in order to determine whether one or more of the formations traversed by the borehole contains oil or gas in 20 commercial quantities.

More particularly, a borehole is normally logged by passing a logging tool or "sonde" through the borehole at the end of an electrically conductive logging cable which is connected at its other end to 25 instruments at the surface. The function of the sonde is to electrically detect one or more lithological characteristics of the earth materials immediately adjacent thereto, and the function of the cable is to transmit such detections to the surface as the sonde 30 moves through the borehole. Accordingly, the surface instrumentation will conventionally include provision for indicating the depth of the sonde in the borehole in correlation with receipt of the signals from the sonde, as well as provision for processing 35 and recording such signals.

It is seldom that a single well logging measurement will provide sufficient basis for a conclusive determination as to the presence of petroleum substances in a particular formation of interest. 40 Accordingly, it is essential that the resulting measurement be registered in a permanent manner whereby it can be studied, and whereby all or portions of the measurement may be compared or correlated with other lithological data. Accordingly, 45 various recording devices such as a pen-type chart recorder or a camera have been developed and used for these purposes.

It is also desirable for the well logging system to include means for observing and monitoring the 50 logging measurement as it is being derived from the sonde, inasmuch as this permits the logging operator to adjust and control the system to provide the most accurate and meaningful measurement. The conventional chart-type recorder is particularly de-55 sfrable in this respect, since the paper chart is easily visible to the operator as the pen moves to draw the log. On the other hand, the resulting paper chart cannot be adjusted once it is produced, nor can the recorder inscribe supplemental data on the chart. 60 Furthermore, dupplicates of the measurement cannot be conveniently obtained for correlation with other data, except by tracing the graph onto another sheet of paper or the like.

The camera recorder, which employs a beam of 65 light which moves appropriately across a strip of photographic film, produces a record which can be easily duplicated. However, the strip of film is relatively inaccessible during the logging operation, and therefore does not permit the measurement to 70 be conveniently observed during the course of the logging measurement.

Recently, improved well logging systems and techniques have been developed such as those described in U.S. Patent Applications S/N 949,592, 75 (of which priority is claimed) wherein the logging measurements are derived in or converted from analog to digital form, and wherein these measurements may be conveniently recorded using magnetic tape. Although this improvement has provided 80 for easy reproduction of an unlimited number of copies of all or any portion of the measurement, and although this has further permitted the measurement to be easily and conveniently correlated and even combined with other lithological data, the 85 magnetic tape does not itself provide for visible observation of the logging data being stored on the tape as such. Accordingly, it is desirable to include a video-type capability in the logging system whereby the logging measurement may be conveniently 90 observed and monitored by the operator as it is derived from the borehole, and whereby the operator may conveniently control and adjust the system and even portions of the measurements as they are generated.

95 The video capability includes a cathode ray tube or the like, wherein the screen presents a visible image of at least the most recent 100 feet (30.48 m) or other preselected portion of the measurement along the "curve", and also together with a further array of 100 horizontal lines to indicate the depth in the borehole at points along the curve. Thus, the logging measurement will appear as a representation which progresses vertically across the video screen to illustrate passage of the sonde along the borehole 105 between the depths indicated by the hosizontal lines on the screen, and the relative horizontal displacement of the curve with respect to the vertical lines on the screen serve to indicate the magnitude of the lithological parameter being derived.

110 As more effective methods are discovered for deriving a plurality of different measurements during the same logging "trip" through the borehole, thus the need to observe these measurements as they are derived and magnetically recorded in a 115 correlative manner is even more important for the reasons hereinbefore set forth. Moreover, the advent of logging systems wherein the measurements are recorded on magnetic tape, has enhanced the need for a video capability to display these measurements 120 to the operator in the most meaningful manner.

It will be apparent that a video capability that will not only accumulate and present an image repreThe date of filing shown above is that provisionally accorded to the application in accordance with the provisions of Section 15(4) of the Patents Act 1977 and is subject to ratification or amendment at a later stage of the application proceedings.

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senting a full preselected segment of the logging measurement, but which will further scroll the image in correlation with travel of the sonde to continually present a full preselected portion of the measure-5 ment at all times, would be far more useful to the operator. If it is assumed that the video screen is composed of an array of 400 lines, each line in turn being composed of 512 points or "stations", however, it will also be readily apparent that this, in turn, 10 would call for a memory capability sufficient to store a total of 204,800 "X-Y" coordinates. More important, it would require a scanning and selection capability which would continually recall and display each of these coordinates at a rate which would be 15 fast enough to avoid producing a flickering image on the video screen.

These disadvantages are overcome with the preferred embodiment of the present invention, however, and novel video display means and method are 20 provided for presenting a scrolling image which is not only continually representative of a full preselected length of logging measurement, but which also eliminates the need for elaborate and highspeed storage, or storage-type oscilloscopes and 25 the like to avoid flicker.

In a particularly suitable embodiment of the present invention, a well logging system is provided of the type depicted and described in the aforesaid U. S. Patent Application S/N 949,592, having a video 30 capability for presenting an image which not only includes an array of vertical and horizontal index lines as desired, but which continually produces a visible curvilinear representation of a full preselected section of the logging measurement in 35 conventional form. More particularly, means are provided to cause both the index lines and the curve to travel across the video screen in response to incoming logging data being provided by the sonde as it passes along the borehole, whereby the image 40 being presented is caused to more realistically and accurately illustrate the logging operations being performed.

As will hereinafter be explained in detail, the video screen will initially generate the image of the logging 45 curve in a progressive manner to illustrate passage of the sonde through the initial portion of the logging operation. Upon completion of this step, however, the image will not erase as in the case of other forms of video display, but will begin to scroll 50 across the screen so as to continue to illustrate the last TOO feet (30.48 m) (for example) of logging measurement being obtained. More particularly,

that portion of the image corresponding to the horizontal index lines on the video screen will also 55 "scroll" in conjunction with the logging curve or curves, at a rate corresponding with passage of the sonde along the borehole, until the logging operation has been completed.

As will also hereinafter be described in detail, 60 scrolling is preferably achieved by the use of separate and different means and methods for creating and scrolling the array of indexing lines in the video image, in contrast with creating and scrolling the logging curve portion of the image. Referring first to 65 the array of index lines, these are preferably provided by a storage which establishes the necessary fixed X and Y coordinates whereby these same coordinates are drawn from the storage each time the image is sought to be generated on the screen. 70 Scrolling of this portion of the image is achieved, however, by merely adjusting the Y coordinates by one depth increment for each newly derived sample to be presented before the image is actually applied to the video screen, such depth increments being 75 derived as a direct function of movement of the sonde through the borehole. Accordingly, this eliminates the need for a storage capacity for the entire possible number of coordinates, and further eliminates any delay which will inherently result from a 80 need to sample through or calculate such a large number of different locations in the storage each time the image is to be presented.

With respect to the portion of the image which is the logging curve, it will be apparent that such a 85 technique is not appropriate since the sonde is continually providing new additional data rather than merely changing one of the coordinates of a preselected quantity of data. Accordingly, instead of changing the Y coordinate for any of the data being 90 extracted from the storage for display, the memory address for the logging curve merely substitutes in memory each newly received increment of logging data for the oldest bit of data then in the storage, and thereafter selects and applies to the video display 95 the various increments of logging data according to their relative seniority in the storage. More particularly, each bit of data in the logging curve storage capability will always be selected and ready out when generating the logging curve portion of the 100 image, but this will occur in a sequence of seniority beginning with the oldest data then in the storage and ending with the newest.

In summary, the preferred embodiment of the present invention will follow a four step sequence 105 for receiving and displaying data, wherein the first step comprises the receiving and storage of data, which may be include a portion of logging signals or inital information relates to the desired overall appearance of the visual images. The second step 110 will comprise the reading from a horizontal line storage alt information necessary to display the horizontal lines, followed by the drawing of all such lines after appropriate adjustment of their Y coordinates when necessary to compensate for newly 115 derived data, whereby the index fines are caused to be displayed in a scrolling manner. In the third step of the sequence, and in like manner, all information necessary to display the vertical lines will be read from a vertical line storage and then drawn, no 120 correlative adjustment of the X coordinates being necessary in that vertical lines will normally not be scrolled.

In the fourth step of the sequence, the logging data storage is sampled in the manner hereinbefore 125 described, and the stored data is then also applied to the display to provide a scrolling representation of the logging curve portion of the image. The system will then recycle to the first state and be held in suspense while the next incoming bit or portion of 130 fogging signal is received and applied to the logging

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data storage in the manner described, whereupon the four steps are repeated as the sonde continued to progress through the borehole.

Although the index lines of the displayed image 5 are derived and scrolled independently of the logging portion of the image, it will be clearly apparent that both portions must be scrolled in coordination with each other. It should be noted that this is inherently accomplished in the present invention, 10 however, since both scrolling functions are derived from or dependent upon derivation of new measurements correlative to movement of the sonde in the borehole.

Accordingly, it is a feature of the preferred 15 embodiment of the present invention to provide an improve well logging system and method, whereby graphical images of logging measurements are displayed at locations having a spatial relation on a viewing screen correlative to the depths within the 20 borehole at which they were derived, and then caused to scroll in functional relation to derivation of additional measurements at different depths. In a particularly suitable embodiment of the present invention, measurements taken over an increment of 25 borehole of one or more well logging parameters are displayed progressing from the shallowest-derived measurements at the top of the screen to the deepest-derived measurements at the bottom. As newly derived measurements at still shallower 30 depths are made, they appear first at the top of the viewing screen, and the move across the screen along with measurements taken at other depths in response to stilt shallower measurements appearing at the top of the screen, and are eventually removed 35 at the other extremity of the screen.

It is another feature of the preferred embodiment of this invention to facilitate monitoring of the logging operation by providing a visual representation of the movement of the sonde through the 40 borehole as measurements are being derived.

It is a further feature of the preferred embodiment of the present invention to provide a continuous display of measurements derived over a preselected increment of the borehole, whereby newly arriving 45 measurements may continually be observed in comparison with those measurements previously derived from the immediately preceding increment of the borehole.

It is a further feature of the preferred embodiment 50 of the present invention to provide a simplified memory technique wherein the number of data coordinates required to be stored has been greatly reduced. In a particularly suitable embodiment of the present invention, a given family of grid lines is 55 uniquely defined in memory by the starting coordinates of each line, and the desired length and number of lines, rather than by storing coordinates of each point on every line in memory.

It is also a feature of the preferred embodiment of 60 the present invention to provide a novel technique for scrolling the horizontal or "depth" lines as well as scrolling the displayed image of logging measurements in functional relationship to the display of additional logging measurements on the screen. 65 Accordingly, provision is made for adjusting fixed Y

coordinates of depth lines which are stored in memory in functional relation to the derivation of additional logging measurements so as to cause these adjusted Y coordinate values to cause the 70 depth lines to appear to scroll on the visual display to the proper new locations. In like manner, as novel technique for scrolling the images of logging measurements is provided wherein measurements are stored at memory locations correlative to the 75 depths at which the measurements were derived, and wherein newly derived measurements are stored at memory locations previously occupied by the oldest derived data.

According to one aspect of the present invention 80 there is provided a system for investigating the lithological character of subsurface earth materials traversed by a borehole, comprising:

logging means adapted to be passed through said bore hole for deriving a plurality of electrical 85 measurements of said materials at a plurality of different depths;

display means having a viewing screen for receiving and presenting visible representations of a plurality of different electrical signals;

SO first signal processing means interconnected with said display means for presenting a first plurality of electrical indexing signals at first preselected locations on said screen in functional relationship to location of said logging means in said borehole, and 95 for presenting a second plurality of electrical index signals at second preselected locations on said screen different from said first preselected locations and infunctional relationship to movement of said logging means in said borehole;

100 second signal means interconnected with said display means for presenting a portion of said measurements at a selected one of said depths at a plurality of said first preselected locations on said said screen infunctional relationship to movement 105 of said logging means in said borehole.

According to another aspect of the present invention there is provided a system for investigating the character of subsurface earth materials and the like, comprising:

110 logging means for providing an electrical logging signal functionally relates to the charater of said materials at a plurality of different depths in the earth;

depth indicating means for providing an electrical 115 depth line in functional relationship to said logging signal at each of said different depths;

first generating means for providing a first control signal functionally representative of a preselected number of different depths;

120 second generating means for providing a second control signal in functional response to said depth line and said first control signal; and display means for graphically displaying selected portions of said togging signal in response to said 125 second control signal, comprising:

starting co-ordinate register means for storing at least one starting x,y coordinate pair for at least one of said electrical depth lines;

line length register means for storing a number 130 correlative to desired length of said at least one of

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said electrical depth lines;

line length counter means interconnected to said co-ordinate register means and said line length register means having an output incrementing from 5 at least one coordinate of said at least one starting co-ordinate pairs to said number; and illuminating means for illuminating a sequence of locations on said display means in response to said output.

10 The invention will be better understood from the following description of a preferred embodiment thereof, given by way of example only, reference being had to the accompanying drawings, wherein: FIGURE 1 is a simplified functional representation 15 of a preferred embodiment of the present invention; FIGURE 2A is a simplified pictorial representation of a one form of visual representation of a typical well logging measurement of the character provided by the structures depicted on Figure 1;

20 FIGURE 2B is another simplified pictorial representation of the type depicted generally in Figure 2A;

FIGURE 3 is a more detailed functional representation of a selected portion of the structures depicted generally in Figure 1; and 25 FIGURE 4 is a more detailed functional representation of another different selected portion of the structures depicted generally in Figure 1.

Referring now to Figure 1, there may be seen a sonde 1 of a type suitable for providing logging 30 measurements of subsurface earth materials traversed by a borehole, means such as a conventional teleprinter 2 for suitably conditioning the system herein depicted, and a master controller 3 which is responsive to the information received from 35 the sonde 1 and teleprinter 2.

Referring more particularly to the measurements provided by the sonde 1, from Figure 1 it may be seen that these measurements are conventionally delivered by means of a logging cable 5 to an 40 interface 6 where they will be appropriately conditioned as required by conversion from analog to digital form, for example, prior to delivery on interface output 6a to controller 3. In a conventional logging operation, however, it is necessary to corre-45 late these measurements to the depths at which they were derived within the borehole. Accordingly, a depth encoder 7 may be provided for generating depth increment signals 7a functionally relates to movement of the sonde 1 within the borehole. This 50 may be achieved by generating increment signals 7a correlative to rotation of a shive wheel 8, which, in turn, is related to movement of the cable 5 over the wheel 8 as the cable raises the sonde 1 from within the borehole. It may be appreciated from Figure 1 55 that the increment signal 7a thus generated and delivered to the interface 6 may be used to achieve correlation of logging measurements to depth by two methods. First, the interface 6 may be designed so as to pass "free running" measurements being 60 continuously derived by the sonde 1 to the controller 3 in response to the increment signal 7a. Secondly, the interface 6 may be designed to generate and transmit a depth command signal in response to the increment signals 7a on cable 5 in the manner 65 previously described in U. S. Patent Application S/N

949,592 which was filed October 10,1978, whereby measurements will be derived by the sonde 1 and transmitted to the surface on cable 5 and to the controller 3 in response to these increment signals 70 7a. In either case, the controller 3 will preferably be receiving a series of logging measurements, each of which may be correlated in a manner to be described to the depth at which they were derived by means of the increment signals 7a.

75 Referring now to the particular graphical images of logging information created by the present invention in response to the information supplied by the sonde 1 and teleprinter 2, as previously noted, there will be seen depicted in Figures 2A and 2B simplified 80 pictorial representations typical of two successive such images. While these images and numbers depicted therein will be used to illustrate operation of the present invention, it should be noted that other images and correlative numbers may be used 85 alternatively. The first image depicted in Figure 2A illustrates the display of a logging curve 9a comprised of logging measurements derived by the sonde 1 at every foot (0.3048 m) as it traverses a preselected 10 foot (3.048 m) increment of borehole from 20 to 90 10 feet (6.096 to 3.048 m). There will also be seen a series of horizontal "depth" lines 10 displayed at every even numbered depth interval within the 10 foot (3.048 m) increment composed of 11 stations each, depicted as dots, as well as a vertical line 11 95 comprised of 11 such stations or dots. It will be appreciated that the purpose of depth lines 10 and the vertical line 11 is to provide appropriate reference points from which to determine the depth at which a particular measurement represented on 100 curve 9a was made, and its relative magnitude, respectively. These depth lines 10 and vertical line 11, as well as the logs 9A and 9B are shown as solid lines for purposes of illustration only. However, it is a matter of choice as to the number of dots of which 105 each may be composed. Thus, by selecting a larger number of dots per inch to display, the various images may appear to approximate continuous lines as closely as desired.

Referring now to Figure 2B there may be seen a 110 second image again illustrating display of a logging curve 9b, again comprised of 11 logging measurements, as well as depth lines 10 and vertical line 11. However, it will be noted that in Figure 2B the 11 measurements derived by the sonde 1, while again 115 made at every 1 foot (0.3048 m) interval over a 10 foot (3.048 m) increment within the borehole, were derived over a different increment from 19 to 9 feet (5.791 to 2.743 m) in depth, rather than from 20 feet to 10 feet (6.096 to 3.048 m) as in Figure 2A. It may be 120 seen from a comparison of Figures 2A and 2B that as the sonde 1 moves from 10 feet (3.048 m) to 9 feet (2.743 m) within the borehole taking correlative measurements at these respective depths, measurement 12 taken at a 10 foot (3.048 m) depth is shifted 125 downward as are all other measurements and replaced at the top of the image by measurement 13 taken at a 9 foot (2.743 m) depth. In like manner, the measurement 14 corresponding to measurements by the sonde 1 at 20 feet (6.096 m) is removed from 130 the bottom of the display and measurement 15 taken

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at 19 feet (5.791 m) thus becomes representative of the deepest measurement derived by the sonde 1 currently being displayed. As the hereinabove procedure is successively repeated in successively dis-5 played images, wherein a newly derived measurement appears at the top of the display and all other measurements shift downward a correlative amount causing the bottommost measurement to disappear from the display, it will be seen that a "scrolling" 10 image of logging measurements is thus produced simulating traversal of the sonde 1 upward through the borehole. Moreover, the depth lines 10 are also made to scroll correlative to the scrolling of the logs 9a and 9b so as to further simulate movement of the 15 sonde 1 and to preserve their value as depth references.

Several things should be noted from the above description of the various images displayed. First, only 11 measurements derived at 1 foot (0.3048 m) 20 intervals over a 10 foot (3.048 m) increment of borehole were displayed, depicting only one well log parameter. Also, depth lines 10 were displayed only at even-numbered depth intervals, and only one vertical line was presented.

25 In practice, however, these numbers may vary dependent upon the desired resolution of the display and various other considerations. For example, it may be desirable to continuously display a 100 foot (30.48 m) increment consisting of measurements 30 taken every one-fourth foot (76.2 mm) or, in other words, to display 400 vertical points with depth lines 10 displayed at 10 foot (30.48 m) increments. This will, accordingly, make the logs 9a and 9b to be more continuous rather than as a series of discrete points, 35 as previously noted, and will facilitate comparison of measurements over a 100foot (30.48 m) increment rather than the IQfoot (3.048 m) increment illustrated. Furthermore, measurements may be required at intervals of one-fourth foot (76.2 mm) or less 40 dependent upon the formations being logged. Still further, it will be apparent that numerous combinations and variations are possible of depth lines 10, vertical lines 11, logs 9a and 9b, and even vertical reference line 11. Moreover, it may also be desirable 45 to display alpha-numeric messages, or symbols such as cross-hatching or the like on the images correlativetothe parameters measured, and to cause this data or symbols to scroll as described.

Stilt further, it may be desirable to cause the number 50 of displayed points, to vary from one log 9a or set of depth lines TO to another, or the like.

Referring now again to Figure 1,the particular technique wherein the hereinbefore described successive images are generated by the present inven-55 tionwill now be described in greater detail. There wilf. first be seen a display screen 16, which may be a conventional cathode ray tube, for converting the signals produced by the display into the desired visible light images such as those depicted in 60 Figures 2A and 2B. As previously noted, these images actually consist of a plurality of illuminated dots, each having discrete locations uniqeuly defined by an X, Y coordinate pair unlike, for example, in conventional "raster" scans well known in the art, 65 such as those employed in televisions and the like. In order to illuminate a particularly described dot, it is only necessary to position a conventional electron beam 17a generated by an electron beam gun 18 at the horizontal and vertical coordinates of the dot by means of a horizontal and vertical deflection signal 19a and 20a, respectively. Moreover, it will be noted that by interrupting the gun output 18a from the gun 18 by means of a switch 17, in response to an intensity control signal 21, the electron beam 17a will also be interrupted such that a particular dot may be either illuminated or extinguished in functional relation to the control signal 21. In Figure 1, there will also be seen conventional digital X and Y counters 22 and 23, respectively, each having correlative X and Y counter outputs 22a and 23a, which are, in turn, transmitted to respective X and Y digital-to-analog converters 19 and 20. It will thus be appreciated that because counter outputs 22a and 23a are discrete digital words, the correlative analog voltages present as horizontal and vertical deflection signals 19a and 20a will also be discrete analog values, causing the display only of discrete points on screen 16 correlative to counter outputs 22a and 23a. Thus, in order to display desired images, it is only necessary to generate and store sequences of digital X-Y pairs of words, and then to display them by means of X and Y counters 22 and 23 in conjunction with intensity control signal 21 in a manner to be described.

it will be recalled that the display of the present invention generates images in response to information provided from the sonde 1 and the teleprinter 2. Because this information may be required by the display for processing more than once, a memory capacity for selectively storing and retrieving this information is provided. Referring again to Figure 1, there will be seen horizontal, vertical and log memories 24,25, and 26, respectively, for this purpose. In order to store information in or retrieve information from memories 24-26, it is necessary to generate and transmit to the memories 24-26 appropriate digital numbers or "address commands" corresponding to each location in a given memory at which it is desired to either store or retrieve the information. Accordingly, a suitable memory address generator 27 and log scroll memory address generator 28 may be provided. In response to a particular horizontal memory address command 27a generated by memory address generator 27, horizontal memory 24 will store or "write" at a correlative memory location within memory 24 any information present on horizontal controller output 3a. If no controlled output 3a is present, however, memory 24, in response to address command 27a, will transmit the information present in the correlative memory location of horizontal memory 24 on one of horizontal memory outputs 24a, 24b, 24c or 24d to its respective line length generator 29,

number of lines counter 30, X register 31, Y register 32, or line scroll generator 33 in a manner to be described. In like manner, memory address commands 27b and 27c will cause any information present on respective vertical and log controller outputs 3b and 3c to be stored in memory locations of their respective vertical and log memories 25 and

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26 at memory locations correlative to the digital words carried on address commands 27b and 27c. Also in like manner, if no information is present on outputs3b or 3c, address commands 27b or 27c will 5 cause information in correlative memory locations of memories 25 or 26 to transmit this information on vertical and log memory outputs 25a-25d and 26a-26d, respectively, to their respective line length register 29, number of lines counter 30, X register 31, 10 orY register 32, in a manner also be described.

In summary, it will be seen that information provided to controller 3 from teleprinter 2 on teleprinter output 2a may be delivered on controller outputs 3a and 3b to their respective horizontal 15 memory 24 and vertical memory 25, and furthermore, may be stored in any memory location of their respective memories 24 and 25 in response to memory address delivered to horizontal memory 24 on address command 27a and to vertical memory 25 20 on address command 27b. Moreover, information thus stored in a particular memory location of memory 24 or 25 may be "readout" or transferred on its correlative horizontal memory output 24a, b, c, or d, or vertical memory output 25a, b, c, or d, to its 25 correlative register or counter by delivering the address command corresponding to the particular memory location to horizontal memory 24 on address command 27a or to vertical memory 25 on address command 27b. Similarly, measurements 30 derived from the sonde 1 may be delivered by controller output 3c to log memory 26 and stored or "written" in a desired memory location determined by the particular address command 27c delivered to logging memory 26. These measurements may also 35 selectively be read from their respective memory location and delivered to the appropriate register or counter in response to their respective address command 27c. It will be noted that an additional address generator, the log scroll memory address 40 generator 28 is provided for delivering an additional address command 28a to log memory 26. The basic function of address command 28a is similar to that of address command 27c in that it permits storage of logging measurements present on controller output 45 3c in a particular memory location of log memory 26 defined by the digital word carried on address command 28a. Address command 28a is still further similar in function to address command 27c in causing measurements thus stored in a particular 50 memory location of log memory 26 to be delivered to an appropriate register or counter on log memory outputs 26a, b, c, or d, in response to the particular digital word carried on address command 28a. However, address generator 28 and its correlative 55 address command 28a are restricted to providing address commands for log memory 26 only for storing or retrieving measurements generated by the sonde 1, and not for information provided by the teleprinter 2.

60 The general method whereby an image is produced on screen 16 should now be apparent. For a given image to be "drawn" once on the screen 16, where the image is a composite of discrete dot locations have discrete X and Y coordinate locations, 65 a series of paired digital words must be generated.

Each pair is correlative to the X, Y coordinates of a different dot displayed in the image, and the total number of pairs will equal the number of dots comprising the image. In a given pair, the word 70 corresponding to the X coordinate of its correlative dot will be presented as X counter output 22a for conversion by converter 19 to analog form as horizontal deflection signal 19a. Simultaneously, and in like manner, the remaining coordinate of the 75 pair, corresponding to the Y coordinate of the dot,

will be presented as Y counter output 23a for conversion by converter 20 to analog form as vertical deflection signal 19a. When deflection signals 19a and 20a are thus present so as to position the 80 electron beam 17a atthe X, Y coordinates of the particular dot on screen 16 when it appears, the beam 17a is briefly energized by control signal 21. Control signal 21 will command switch 17 to briefly pass gun output 18a through switch 17, thus illumi-85 nating the dot which is extinguished with removal of control signal 21. The deflection signals 19a and 20a, in response to the next pair of words of the next dot present on counter outputs 22a and 23a, are permitted to change to their next values without the beam 90 17a being present, thus avoiding creation of a line on screen 16 between successively drawn dots as the deflection signal 19a and 20a change. It may thus be seen that, in order to generate a desired image, it is only necessary to generate and illuminate as he-95 reinbefore described successive pairs of digital words, each pair of which corresponds to one of the dots comprising the image. Still further, a given image may be "re-drawn" by again illuminating these words pairs. It will thus be appreciated that by 100 doing so at a fast enough rate, for example, every 17 milliseconds, although each dot may be alternately illuminated and extinguished, the image may thus appear to be relatively constant and not to "flicker" noticeably.

105 It thus remains to be understood the manner in which the hereinbefore noted pairs of digital words are generated. In order to generate an image as hereinbefore described, it is convenient to divide the various functions performed by the present inven-110 tion into four categories in the order in which they may be performed, namely, the receiving of logging measurements and other information, the generation and scrolling of horizontal lines, the generation of vertical lines, and, finally, the generation and 115 scrolling of logging curves. Specifically regarding, for example, the first function of receiving logging data, it will be recalled that information may be provided from two sources, the teleprinter 2 and the sonde 1. It will be appreciated that prior to displaying 120 logging images, some additional information regarding the desired general appearance of the images and the like must be provided, and this function may conveniently be performed by the teleprinter 2. Such information may include the 125 number of depth lines 10, vertical lines 11, and logs 9a to be displayed, and the like. Referring more particularly, for example, to the function of drawing depth lines 10, it will be noted that to uniquely define a given number of such lines, all that may be 13Q required is the starting X and Y coordinates of the

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first dot of each such line, the desired total number of such lines to be drawn, and their lengths. In a particular embodiment of the present invention, it will be noted that because all data may be displayed 5 as points of light or dots having discrete locations on the screen 16, the desired length of a line may be defined by selecting the total number of dots of which the line will be composed. It will further be noted, that it is desirable, though not necessary, that tO families of vertical and horizontal lines begin at the same Y and X coordinates, respectively, and therefore only one beginning X coordinate may be required for a family of horizontal lines, for example. In summary, then, regarding the preparation of the 15 display for performing the function of drawing depth lines 10, initial information must be provided and stored in the horizontal memories 24. This information is the desired horizontal line length, number of horizontal lines, X coordinate of the first point on a 20 horizontal line, and the Y coordinate of each horizontal line. It will be appreciated that controller 3 may be adapted to generate this information and provide it to the appropriate controller outputs 3a in suitable digital form, in preparation for storage in horizontal 25 memory 24. Moreover, controller 3 may generate this information in response to data delivered to the controller 3 from input data provided by a human operator, to the teleprinter 2, such as desired horizontal line length, number of horizontal lines, 30 and starting X, Y coordinates of the first dot of the first line from which all other necessary information may be computed by the controller 3.

Referring now to the following Table I, there may be seen an illustrative "memory map" or arrange-35 ment of memory locations in memories 24-26, wherein data required by the display to perform its various functions may be stored and retrieved. More particularly, it will be seen that memory locations 1 -9 have been reserved as the particular locations in 40 horizontal memory 24 wherein the previously mentioned required data for drawing horizontal lines is stored awaiting retrieval. Specifically, referring to the illustrative image depicted in Figure 2A, location 1 contains the digital word for the number "11", 45 corresponding to the desired number of dots per line which are selected to achieve the desired visual resolution of the horizontal lines. Location 2 contains the digital word for the number "6", corresponding to the number of horizontal lines which are to be 50 displayed. Location 3 contains the digital word for "0" corresponding to the beginning X axis location for all such horizontal lines which, as previously noted, may be identical for the given family of horizontal lines. Finally, it will be seen that locations 55 4-9 are reserved for the digital representations of the particular Y axis location of each horizontal line, namely, 0,2,4,6,8, and 10. It will thus be seen that memory locations 1 through 9 contain all information necessary to uniquely define the desired family 60 of horizontal lines depicted in Figure 2A. Further inspection of the memory location map reveals that memory locations 10-13 contain similar information necessary to define the vertical line of Figure 2A, and that memory locations 14-16 provide the initial 65 information necessary to define the logging curve 9a of Figure2A.

The general manner in which data shown in the contents of memory locations 1-9,10-13, and 14-16 which are present in master controller 3 in response 70 to teleprinter output 2a are stored in and retrieved from their various respective memories 24-26 in response to address commands has previously been described but requires further explanation at this point. Referring to Figure 1 there will be seen a video 75 controller 34, which, in response to a controller output 3d from controller 3 signifying that controller 3 has data corresponding to that shown in memory locations 1-9,10-13, and 14-16 ready at its outputs for storage, controller 34 will generate an enabling 80 signal 34n delivered to memory address generator 27. Address generator 27 will then generate a sequence of address commands 27a which are delivered to horizontal memory 24 and correspond to digital representations of memory locations 1-9. 85 Video controller 34 will also generate a transfer command 34p causing controller 3 to transfer on output 3a to horizontal memory 24 the information shown in memory locations 1-9 of the memory map to their respective memory locations 1 -9 in horizontal 90 memory 24. When video controller 34 detects that this task is completed, as indicated by another enable signal 34n transmitted to video controller 34 from memory address generator 27, the video controller 34 will then proceed to cause transfer in 95 like mannerof the information in master controller 3 corresponding to the contents shown in the memory map of memory locations 10-13 and 14-16 to their appropriate respective places in vertical and log memory 25 and 26, respectively.

100 Thus, as with storage of initial information in memory locations 1-9 of horizontal memory 24, the video controller 34 will generate a next enabled signal 34n causing memory address generator 27 to generate a next sequence of address commands 105 27b, delivered to vertical memory 25. Address commands 27b will be digital representations of memory locations 10-13 and, in like manner to storage in the horizontal memory 24, will cause the information shown in memory locations 10-13 of the 110 memory map which are contained on controller output 3b to be transferred in sequence and stored in correlative memory locations of vertical memory 25 in response to a next transfer command 34p from video controller 34 to controller 3. This process will 115 then be repeated for the log memory 26 so as to store the information indicated in memory locations 14-16 in its correlative memory locations in log memory 26. Once the initial information contained in memory location 1-16 is sequentially stored in 120 memories 24-26, as previously described, and detected in the video controller 34 from the third enable signal 34n, the display will proceed to its next task of drawing the first desired horizontal line, such as that shown in Figure 2A.

125 In order for the first horizontal line to appear on screen 16, the information contained in memory locations 1-4 shown in the memory map must first be retrieved or "read" from the horizontal memory 24 and stored at appropriate places. Specifically, in 130 response to a next enable signal 34n, the memory

8

GB 2 110 907 A

8

address generator 27 will generate a next sequence of address commands 27a to cause transfers of data from horizontal memory 24 as previously de-scribed.The number of increments or dots per 5 horizontal line, "11", contained in memory location 1, will be delivered on horizontal memory output 24a to line length register 29. In like manner, the number of horizontal lines desired ("6") is retrieved from memory location 2 in response to a next address 10 command 27a and delivered to number of line counter 30 on horizontal memory output 24b. The beginning X and Y axis coordinates (0,0) for the first line are retrieved from locations 3 and 4, respectively, from horizontal memory 24, and are hereafter 15 delivered to a suitable X hold register 31 on horizontal memory output 24c and to line scroll generator 33 on horizontal memory output 24d. For purposes of simplifying explanation of the present invention, it will be assumed, for the moment, that until the 20 scrolling feature is performed, horizontal memory output 24d will be passed directly through line scroll generator 33 on line scroll generator output 33a. When the last such retrieval has been completed, as detected by video controller 34 from enable signal 25 34n, a series of register transfer commands 34a, b, and c, generated by video controller 34 will cause transfer of the numbers stored in their respective registers 29,31, and 32, to their respective counters. Specifically, line length register 29 will thus 30 transfer its stored number on line length register output 29a to line length counter 35, X register 31 will transfer its number on X register output 31 a to X counter 22, and Y register 32 will transfer its number on Y register output 32a to Y counter 23. After the 35 various counters have thus been set up in the manner just described, X counter 22 will deliver the digital representation of its coordinate ("0") stored in X hold register 31 on counter output 22a to a conventional X axis digital - to - analog converter 19 40 for conversion to analog form. After such conversion, the analog equivalent to this X coordinate will be delivered as horizontal deflection signal 19a to position the beam 17a of the display at the appropriate horizontal location for the first point of the first 45 horizontal line. In like manner, Y counter 23 will deliver on counter output 23a the digital representation of the beginning Y coordinate ("0") of the first desired horizontal line stored in Y hold register 32 to a conventional Y axis digital - to - analog converter 50 20 which, after converting this digital word to analog form, will position the beam 17a at the appropriate beginning Y coordinate. Each time the intensity signal 17a is thus "aimed" at an X,Y coordinate location wherein a dot of light is desired, the video 55 controller 34 will "decode" or sense this state. This is because the rate at which the X and Y counters 22 and 23 are incremented, or in other words, the rate at which newX, Y coordinate pairs are generated is controlled by video controller 34 since it generates 60 increment signals 34g and 34f, respectively, to increment the counters 22 and 23. Each time a new coordinate pair is thus generated and the equivalent analog voltage appears on horizontal and vertical deflection signals 19a and 20a, respectively, the 65 video controller 34 will generate an intensity control signal 21, causing the electron beam 17a to create a light dot on theface of the screen 16 at the desired location correlative to the particular X, Y coordinate.

Unlike the Y counter 23, however, which will 70 maintain a constant output "0" corresponding to the value of memory location 4, X counter 22 will then begin counting up from the initial X coordinate "0" stored in the X hold register 31. Each time the X counter 22 is incremented in response to X incre-75 ment siignal 34g, this causes a correlative and discrete increase in X axis deflection signal 19a which, in turn, causes the beam 17a to move to the right by a corresponding discrete amount while remaining at the previous Y coordinate. It will be 80 recalled that in order to define the length of a particular line it was necessary to define the number of dots or increments per line which were desired, and that this number was presented to the line length register 29. Each time the X counter 22 is 85 incremented, thus moving the beam to the right one step, the line length counter 35 is correspondingly incremented by the line length increment signal 34h. When the line length counter 35 reaches the number "11" corresponding to the fact that the X counter 22 90 has caused the last dot of the first horizontal line to be drawn, and thus the line has been completed, this will be detected on signal 34h by controller 34 and the number of lines counter 30 will accordingly be decremented by 1 in response to number of lines 95 counter signal 341 and will now hold the value "5" indicating five horizontal lines remain to be drawn. Accordingly, the Y coordinate for the second horizontal line ("2") will then be read from memory location 5 contained in the horizontal memory 24, 100 and this information will thereafter be transferred to the Y counter 23 in the manner previously described. In the illustrated embodiment of the display, although not required, lines in a given direction may desirably be of the same length and begin at the 105 same axis coordinate to which they are parallel, as hereinbefore noted. Accordingly, it will be appreciated thatforthe second horizontal line, the digital representation of the number of dots per line contained in the line length register 29, as well as the 110 initial X coordinate of the second line contained in X register 31 will be identical to that of the first line, and only need be transferred to their respective counters 35 and 22 as previously described in preparation for drawing the second horizontal line. 115 The second horizontal line will be drawn in a manner similar to that of the first line, with line length counter 35 and X counter 22 incrementing each time a dot is drawn. This process will continue for each desired horizontal line, wherein priorto drawing 120 each successive line, the number of lines counter 30 is decremented by 1 and the appropriate Y coordinate for the new line is read from one of the remaining memory locations 6-9. It will be appreciated that when both the line length counter 35 125 reaches the number "11" stored in line length register 29 and the number of lines counter 30 has reached "0", the last dot of the last horizontal line has been drawn, as sensed by the controller 34 on signals 34h and 34I, and the video controller 34 is 130 thereby ready to perform its next function of draw-

9

GB 2 1T0 907 A

9

ing vertical lines.

In summary, it may be appreciated that the video controller 34 is continually in alternating states wherein it commands the various registers and 5 counters to be first appropriately "set up" with necessary information, and this information is thereafter used secondly to write the desired information on the screen 16. Moreover, with respect to the writing of horizontal lines, the video controller 34 10 detects two states. First, it determines when the line length equals "11" and the number of lines remaining does not equal "0", in which case the video controller 34 will set up counters 35,22, and 23 to draw the next line. Secondly, the video controller 34 15 will determine when both the increments per line remaining as well as the number of lines to be drawn remaining equal 0, in which case the function of drawing the horizontal line has been completed, causing the video controller 34 to begin to set up the 20 various registers and counters to perform the next function of drawing vertical lines. From inspection of the information stored according to the manner previously described in memory locations 10-13 of vertical memory 25 related to the drawing of vertical 25 lines, it will be appreciated that the manner in which this second function of the display is accomplished is similartothat performed in drawing horizontal lines, as previously described. More particularly, however, with the exception of the scrolling of 30 horizontal lines to be hereinafter described, the basic steps performed to draw vertical lines is identical to that of horizontal lines with two exceptions. First, instead of holding a Y counter output 23 constant for a given line while X counter 22 is incremented, for 35 vertical lines this situation is reversed wherein for each line the X counter 22 is held at a constant value while the Y counter 23 is incremented. Secondly, in the image illustrated in Figure 2A, only one vertical line is depicted which is reflected in the fact that 40 unlike in memory locations 5-9 wherein Y coordinates for successive horizontal lines are stored, no such correlative X coordinates other than the first stored at memory location 13 are present. This corresponds to the fact that for purposes of illustra-45 tion only one vertical line was generated. However, it will be apparent that by providing in suitable memory locations additional X coordinates of successive vertical lines, they may be drawn in a manner analogous to that of the horizontal lines. 50 Unlike the method for scrolling log curves to be described, wherein the address commands 28a to the log memory 26 are adjusted in relation to derivation of new measurements, the depth lines are made to appear to scroll by adjusting their Y 55 coordinates after they are read from the horizontal memory 24 in relation to the derivation of the new measurements. Referring now more particularly to Figure 4, there will be seen a vertical line length register 39. When the video controller 34 is prepar-60 ing to draw depth lines, a number 1 less than the number of log measurements to be displayed stored in memory location 14 of vertical memory 25, will be transferred to the register 39 on video controller output 34m. In the example of Figure 2A, this 65 numberwillrof course be "10",There will also be seen in Figure 4 an accrued sample counter 40, which, in response to each depth increment signal 7a, will generate a digital number on counter output 40a, which is 1 higher than that previously generated, until the number on the counter output 40a equals that of the register output 39a of register 39. This event may be conveniently detected by a comparator 41, which continuously compares the counter output 40a and the register output 39a.

When it occurs, the comparator 41 will generate a comparator output 41 a, thus resetting the counter 40 to the number "0", which will also always be the value that the counter 40 will be preset to prior to display of the depth lines. Thus, it will be noted that with each newly derived log measurement, indicated by the depth increment signal 7a, a number on the counter output 40a will be generated, and will increment by 1 with each new measurement starting at "0" until the number "10" is reached, at which time the counter 40 will reset to "0". Still referring to Figure 4, there will be seen a subtractor 42. Each time a y coordinate of a depth line is read from the horizontal memory 24, this number will be delivered on the horizontal memory output 24d to the subtractor 42, and then subtracted from the number then present at the counter 40a output. The subtractor 42 will then generate a subtractor output 42a which is the numerical difference between these numbers, and deliver this difference to a comparator 43 and to a storage 44. The comparator 43 will then determine whether the difference is less than 0. If it is not, then the difference will be delivered as a comparator output on the line scroll generator output 33b to the

Y register 32 and will be the Y coordinate value used to generate the particular depth line in a manner previously described. However, if the difference in the comparator 43 is less than 0, the comparator 43 will generate a comparator output 43a which will cause the number previously stored in the storage 44 to transfer to subtractor 42 on the storage output 44a. The comparator output 43a will also cause the number stored in the register 39 to be transferred to the subtractor 42 on the register output 39a. The subtractor 42 will then subtract the number delivered from the storage output 44a from the number delivered from the register 39, and thus generate the result as the line scroll generator output 33a. The line scroll generator output 33a will, in like manner to the line scroll generator output 33b, then be used as the

Y coordinate value to generate the particular depth line, also in a manner previously described.

A numerical example at this point will be helpful in illustrating the manner in which the depth lines are made to appear to scroll. Referring to Figure 2A, it will be recalled that six depth lines have been generated, the first from the bottom corresponding to a depth of 18 feet (5.486 m) and a Y coordinate of "2". It will be assumed that between the time at which the image of Figure 2A and Figure 2B have successively been displayed, a new log measurement dot shown as measurement 13 has been generated from a depth of 9 feet (2.743 m) and is ready to be displayed. Accordingly, it will further be appreciated that as this measurement 13 appears in the display of Figure 2B, the depth line at 18 feet

70

75

80

85

90

95

100

105

110

115

120

125

130

10

GB 2 110 907 A

to

(5.486 m) must be moved downward by one space to a Y location of "1" to thus simulate the traversal of the sonde 1 by 1 foot (.3048 m) further up the borehole. Referring to Figure 4, it will thus be seen 5 that when the display is preparing to draw the 18 foot (5.486 m) depth line illustrated in Figure 2B, the number "2", corresponding to the Y location of the first depth line from the bottom shown in Figure 2A and stored in memory location 5, will be presented 10 to the subtractor 42 on horizontal memory output 24d. Still further, because the accrued samples counter 40 has received one pulse on depth encoder output 7a, corresponding to the fact that one additional measurement has been derived, accrued 15 samples counter 40 will have present on counter output 40a the number "1". As previously described, the subtractor 42 will determine the difference between these two numbers and transmit this difference, which is "1" on the subtractor output 42a 20 to the comparator 43. As previously described,

because this difference is not less than 0, the number "1" will be transmitted as line scroll generator output 33b to the Y register 32 as the adjusted new Y coordinate for the depth line appearing at 18 feet 25 (5.486 m). Accordingly, it will be seen from Figure 2B that the depth line appearing at 18feet (5.486 m) will thus be displayed at a new Y coordinate value of "1", causing this line to appear to scroll downward in relation to its previous location shown in Figure 2A. 30 If it is assumed that three new log measurements have been derived, and thus the accrued samples counter 40 has not yet been reset to "0", the counter output 40a will present the number "3" on counter output 40a to the subtractor 42. However, the 35 number "2" will be delivered on the horizontal memory output 24d to the subtractor 42, as it will be recalled that the Y coordinate of a particular depth line will always remain at the value assigned it when initially stored in the horizontal memory 24. The 40 subtractor 42 will then, as before, determine the difference between these numbers and deliver the result on the subtractor output 42a to the comparator 43. In this particular case, the difference between "2" and "3" will be "-1". It will be recalled that this 45 difference of "—1" will also be delivered to the storage 44. The comparator 43, after determining that the difference is less than 0, will instruct the register 39, in response to comparator output 43a to deliver the register output 39a, which will be the 50 number "10" to the subtractor 42. The comparator output 43a will also cause the storage 44 to deliver the number "1" on storage output 44a to the subtractor 42. The subtractor 42 will then determine the difference between register output 39a, which is 55 "10" and the storage output 44a which is "1", and will deliver the result, which is "9" on the line scroll generator output 33a. This Y coordinate value of "9" will thus be used as the new Y coordinate value for the depth line of 18 feet, shown in Figure 2B, after 60 three more measurements have been derived. It will be appreciated that this new location of the 18 foot (5.486 m) depth line at a Y coordinate value of "9" coincides with the location of the depth line shown at a depth of 10 feet (3.048 m) in Figure 2B. It will 65 thus be appreciated that the net effect of adjusting Y

coordinate values of the depth lines is to cause the depth lines to move downward or scroll until they reach the bottom of the display, at which time they will reappear at the top of the display and continue 70 to move downward in functional relationship to the receipt of new logging measurements.

Referring now to the function of displaying and scrolling logging curves performed by the present invention, it will be recalled that prior to the display 75 of images, it was necessary to provide certain information regarding the desired general appearance of the images through means of a teleprinter 2 of the like. It will also be recalled that in particular, this information included that shown in memory 80 locations 14-16 regarding the drawing of logging curves, and that this information was stored in the log memory 26 in a manner previously described in response to address commands 27c generated by the memory address generator 27. When the display 85 is performing the function of drawing curves, this data must be retrieved from the log memory 26 and stored in appropriate registers and counters for similar reasons as when the grid lines are being drawn. Specifically, when the video controller 34 has 90 determined that the last vertical line has been drawn in a manner previously described, and it is thus time to begin drawing the logging images, enabling signal 34n will cause the address generator 27 to generate appropriate address commands 27c so as 95 to cause the vertical log curve length number "11", stored in memory location 14, to be transferred on log memory output 26a to line length register 29. In like manner, the number of curves, "1", stored in memory location 15 will be transferred on log 100 memory output 26b to the number of lines counter 30, and the Y coordinate of the beginning of the log curve, "0", stored in memory location 16, will be transferred on log memory output 26d to the Y register 32. When this data has thus been retrieved 105 and transferred, logging curves will thereafter be displayed and scrolled in a mannerto be described.

Referring now to the following Table IIA, there will be seen a reproduction of a portion of the previously illustrated memory map of Table I related to the 110 image 9a of vertical logging curve measurements depicted in Figure 2A. As can be seen from columns (c) and (d) of the table, when a logging operation is begun, memory locations 17-27 reserved for storing measurements in log memory 26 will have "0" 115 values stored, corresponding to the fact that no measurements have been taken. However, as the sonde 1 prog resses up the borehole, taking successive measurements, as indicated in columns (e) through (h), they will be stored successively in 120 memory locations 27,26, and so forth, until all memory locations allotted to logging measurement storage have been occupied, as shown in column (h). Thereafter, as illustrated in column (j) of Figure 2B, once all memory locations have been filled, each 125 successively derived measurement will be stored in a memory location occupied by the measurement which was previously derived from the deepest location within the borehole. For example, as shown from columns (i) and (j) of Table IIB, a measurement 130 having a value "3" derived from a depth of 9 feet

n

GB 2 110 907 A 1t

(2.74m) has been stored in memory location 27, thus replacing the previous measurement of "5" derived at a 20 foot (6.096m) depth. This corresponds to the measurement 13 shown in Figure 2A. This process 5 will be repeated as new measurements are derived at progressively shallower depths, wherein measurements at 8 feet (2.438m) replace those of 19 feet (5.791m) and are stored on memory location 26, measurements at 7 feet (2.124m) replace those at 18 10 feet (5.486m) and are stored in memory locations 25, and so forth. It will be appreciated that every time the last measurement replaced is at memory location 17, the next memory location to be filled will be memory location 27. The process will thus "recycle" 15 and continue, wherein measurements in successively lower memory locations are replaced.

The method whereby images of logging measurements are thus made to appear may now be seen. Whenever an image of a logging curve such as that 20 of Figure 2A is desired, several things must occur. First, every logging measurement X coordinate value will be read from log memory 26 in sequence from the deepest derived measurement to the shallowest, and then be converted to horizontal 25 deflection signal 19a in a manner previously described. Simultaneously, correlative Y values will be generated for each X value and presented as vertical deflection signal 20a so as to cause the X values to appear at the proper elevations on screen 16. Beam 30 17a will then be turned on and off to illuminate the dot corresponding to the particular X,Y pair. Because the X values will preferably be read in order from the deepest derived to shallowest, as previously stated, it is only necessary to cause Y counter 23 to 35 present a "0" value to the vertical converter 20 correlative with the reading of the first X value and its conversion by horizontal converter 19, and to thereafter increment Y counter 23 with each corresponding successive reading of the next X value. In 40 this manner, images such as those of Figures 2A and 2B may thus be produced, wherein dots in a given image will be drawn starting with the lowest dot on the screen 16, and corresponding to the deepest derived measurement, and progressing upwardly as 45 successive dots are drawn.

In order to achieve the illusion of scrolling of logging images, it should now be apparent that only two additional requirements are necessary. First, it will be necessary to provide a technique for generat-50 ing at the appropriate times when a newly derived measurement is to be stored, address commands correlative to the memory location of the deepest derived measurement presently stored in log memory 26 so as to cause this newly derived measure-55 ment to replace the deepest derived measu rement, as previously explained. Moreover, it will further be necessary when all logging measurements are successively read from log memory 26 and displayed, to provide a technique for generating a sequence of 60 address command numbers correlative to the memory location numbers wherein the measurements to be displaced are stored, and further correlative to the order in which these measurements will be displayed. For example, in order to draw the image 65 of the log curve 9a shown in Figure 2A,the measurements stored in memory locations 17-27 will be sequentially read from log memory 26 and displayed in order from memory location 27 to 17, and accordingly a sequence of address commands 70 numbered in orderfrom 27 to 17 must be generated. In like manner, in order to generate the image of the log 9b depicted in Figure 2B, memory locations 26 through 17 and 27 must be sequentially read and displayed in order with correlative Y values from "0" 75 to "10". Accordingly, a sequence of numbered address commands 26-17 and 27 must be generated.

Referring now to Figure 1, there will be seen a log scroll memory address generator 28 for providing these required address commands 28a. For storing 80 and retrieving measurements, as each measurement from the sonde 1 is derived, processed by the controller 3, and made available on controller output 3c for storage in the log memory 26, the address generator 28 will generate an appropriate numbered 85 address command 28a to cause the measurement to be stored in the proper memory location of logging memory 26 as described. In like manner, as each image of a log curve such as log 9a of Figure 2A is drawn on the screen 16, the address generator 28 90 will also generate a sequence of such numbered address commands 28a so as to cause the measurement stored in each memory location 17-27 to be read out on log memory output 26d and displayed in the proper order as also described. In Figure 3 there 95 may be seen a more detailed representation of the address generator 28 for generating address commands 28a. Address command generator 28 will preferably have a number of measurements register 45 wherein there will be stored the total number of 100 log measurements or dots to be displayed for a given log, or in the case of illustrative log 9a depicted in Figure 2A, the number "11". Address command generator 28 will also preferably have a suitable ring counter 36. Ring counter 36 will be 105 designated to preset prior to operation of the display so as to produce the digital word equivalent to the highest numbered memory location on its address command 28a output, or "27" in the case of the previously illustrated memory map of Table I. The 110 ring counter 36 will further be designed to produce a sequence of successively lower digital numbers at its output 28a, wherein each sucessive number is generated in response to either a depth increment signal 7a or a counter output 38a. There will also be 115 seen in Figure 3 a comparator 37 which will generate a reset signal 37a resetting the ring counter 36 to its preset value "27" when the digital number presented to the comparator 37 on address command 28a from the ring counter 36 is equal to the digital 120 word presented to the comparator 37 on the register output 45a from the register 45. In other words, the numbers present on address command 28a will be successively lowered by 1 in response to either a depth increment signal 7a or counter output 38a 125 until the address command 28a equals the number "11" which will be the register output 45a, whereupon the ring counter 36, in response to reset signal 37a, will be reset to its preset value "27". Thus, it may be seen how an appropriate address command 130 28a is always generated from the ring counter 36 so

12

GB 2 110 907 A

12

as to store logging measurements in their proper memory location after they are derived. Referring to columns (a) and (e) of Table IIA, it will be seen that the first derived measurement of Figure 2A, the 5 number "5" must be stored in memory location 27. Depth encoder 7 will accordingly generate a first depth increment signal 7a causing the ring counter 36 to generate its first address command 28a, or the number "27" which it was preset to. Accordingly, 10 when the measurement "5" is present on controller output 3c, it will thus be stored in memory location 27 of the log memory 26 in response to the address command 28a carrying the number "27". Each time a new measurement is made at successively shal-15 lower depths, a depth increment signal 7a will cause the ring counter 36 to generate successively lower numbered address commands 28a correlative to successivly lower numbered memory locations, so as to cause each newly derived measurement to be 20 stored in its appropriate memory location of the log memory 26, as shown in column (h) of Table IIA. Moreover, when the last available memory location 17 had been utilized, the next depth increment signal 7a will cause the ring counter 36 to rest to the value 25 "27". This will generate an address command 28a of the value "27" so as to store this next derived measurement 13 of Figure 2A in the memory location 27 wherein previously the deepest derived measurement 14 of Figure 2A was stored, as shown 30 in column (h) of Table IIA and as previously discussed. Referring now to the genreation of an appropriate sequence of address command 28a number in order to readout measurements stored in the log memory 26 in the proper order for subsequent 35 display, there will be seen in Figure 3 a number of measurements counter 38. When the video controller 34 is ready to perform the function of drawing the logs such as log 9a of Figure 2A, the video controller 34 will generate a log command signal 34j causing 40 the register 45 to transfer on register output 45b to counter 38 the number stored in register 45 which is "11", the number of measurements which are to be displayed. The video controller 34 will then generate a next log command signal 34k which, in turn, will 45 cause the counter 38 to generate a series of 11 signals on counter output 38a, each of which will cause the ring counter 36 to generate an output 28a correlative to memory locations which will be one less than that previously generated by the ring 50 counter 36, unless the previous number was "17", in which case the ring counter 36 will generate a next address command 28a of the value "27", after resetting in the manner previously described. Thus, it will be seen that in this manner a sequence of 55 address command 28a numbers for each memory location will be generated wherein the first memory location number on address command 28a will be that location where the deepest derived measurement is currently stored in log memory 26, and 60 wherein the last such number will be the memory location wherein the shallowest derived measurement is stored. For example, regarding the log 9b depicted in Figure 2B, address command 28a numbers 26-17, and 27 will be generated in sequence, 65 and their respective measurements in the correlative memory locations also displayed in sequence, starting at the bottom of the screen 16, as shown in Table llB. It will also be seen that if, in the time between two successive complete displays of a logging curve 70 image no additional measurements have been taken, each series of address command 28a numbers used to readout and display all measurements contained in memory locations 17-27 will be identical. In other words, in the display of log 9a of Figure 75 2A, address command 28a numbers 27 through 17 will be generated each time the log 9a is displayed. However, after the measurement at 9 feet (2.743m) is made and stored in log memory 27, the log 9b of Figure 2B will be displayed, wherein the address 80 command 28a numbers will change in sequence to 26 through 17 followed by 27 each time the log 9b is displayed until additional measurements are derived.

GB 2 1tO 907 A

13

TABLEI

MEMORY

LOCATION CONTENTS VALUE

1

Horizontal line length

11

2

Number of horizontal lines

6

3

X Coordinate of beginning of horizontal lines

0

4

Y Coordinate of first horizontal line

0

5

Y Coordinate of second horizontal line

2

Horizontal

Lines

6

Y Coordinate of third horizontal line

4

7

Y Coordinate of fourth horizontal line

6

8

Y Coordinate of fifth horizontal line

8

9

Y Coordinate of sixth horizontal line

10

10

Vertical line length

11

11

Number of vertical lines

1

Vertical

Lines

12

YCoordinate of beginning of vertical lines

0

13

X Coordinate of first vertical line

0

14

Vertical log curve length

11

15

Number of curves

1

16

Y Coordinate of beginning of log curves

0

17

X Coordinate of 11th logging measurement

1

18

X Coordinate of 10th logging measurement

3

19

X Coordinate of 9th logging measurement

5

Vertical

Logging

20

XCoordinateof 8th logging measurement

4

Curve

Measurements

21

X Coordinate of 7th logging measurement

3

22

X Coordinate of 6th logging measurement

2

23

X Coordinate of 5th logging measurement

1

24

X Coordinate of 4th logging measurement

2

25

XCoordinate of 3rd logging measurement

3

26

XCoordinate of 2nd logging measurement

4

27

X Coordinate of 1st logging measurement

5

TALBLEIIA

TABLE IIB

(a)

(b)

(c) (d) (e) (f) (g) (h)

0)

(j) (k)

MEMORY

LOCATION

(Y=)

DEPTH (FT) MEASUREMENT(X=) DEPTH (FT) MEASUREMENT(X=) (Y=)

17

10

10 0 0 0 0 1

10

1 9

18

9

11 0 0 0 0 3

11

3 8

19

8

12 0 0 0 0 5

12

5 7

20

7

13 0 0 0 0 4

13

4 6

21

6

14 0 0 0 0 3

14

3 5

22

5

15 0 0 0 0 2

15

2 4

23

4

16 0 0 0 0 1

16

1 3

24

3

17 0 0 0 0 2

17

2 2

25

2

18 0 0 0 3 3

18

3 1

26

1

19 0 0 4 4 4

19

4 0

27

0

20 0 5 5 5 5

9

3 10

Claims (2)

1. A system for investigating the lithological character of subsurface earth materials traversed by a borehole, comprising:

5 logging means adapted to be passed through said bore hole for deriving a plurality of electrical measurements of said materials at a plurality of different depths;

display means having a viewing screen for receiv-10 ing and presenting visible representations of a plurality of different electrical signals;

first signal processing means interconnected with said display means for presenting a first plurality of electrical indexing signals at first preselected loca-15 tions on said screen in functional relationship to location of said logging means in said borehole, and for presenting a second plurality of electrical index signals at second preselected locations on said screen difference from said first preselected loca-20 tions and in functional relationship to movement of said logging means in said borehole;

second signal means interconnected with said display means for presenting a portion of said measurements at a selected one of said depths at a 25 plurality of said first preselected locations on said screen in functional relationship to movement of

M

GB 2 1T0 307 A

14

said logging means in said borehole.

2. A system according to claim 1 wherein the first signal processing means comprises: starting coordinate registers for storing the starting X,Y coordinates of at least one index mark; a line length register

65 for storing a number indicative of the visible length of said at least one index mark; and line length counter means connected to the starting coordinate registers and to the line length register to provide said electrical signals to the display means in-70 crementingfrom at least one coordinate of said starting X,Y coordinates of the said at least one index mark to a value correlative to the corresponding coordinate of the end of said at least one index mark.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd., Berwick-upon-Tweed, 1983

Published at the Patent Officer25 Southampton Buildings, London, WC2A1AY, from which copiesinay be obtained.

2. A system for investigating the character of subsurface earth materials and the like, comprising: logging means for providing an electrical logging 5 signal functionally related to the character of said materials at a plurality of different depths in the earth;

depth indicating means for providing an electrical depth line in functional relationship to said logging 10 signal at each of said different depths;

first generating means for providing a first control signal functionally representative of a preselected number of different depths;

second generating means for providing a second 15 control signal in functional response to said depth line and said first control signal; and display means for graphically displaying selected portions of said logging signal in response to said second control signal, comprising:

20 starting co-ordinate register means for storing at least one starting x,y coordinate pair for at least one of said electrical depth lines;

line length register means for storing a number correlative to desired length of said at least one of 25 said electrical depth lines;

line length counter means interconnected to said co-ordinate register means and said line length register means having an output incrementing from at least one coordinate of said at least one starting 30 co-ordinate pairs to said number; and illuminating means for illuminating a sequence of locations on said display means in response to said output.

35 New claims filed on 17 Dec. 1982 Superseded all claims

1. A system for investigating the lithological character of subsurface earth materials traversed by

40 a borehole, comprising: logging means adapted to be passed through said borehole for deriving a plurality of electrical measurements of said materials at a plurality of different depths; display means having a viewing screen for receiving and presenting 45 visible representations of a plurality of different electrical signals; first signal processing means for providing electrical signals to the display means to form a plurality of index marks on the viewing screen at locations on the viewing screen repre-50 sentative of depths in said borehole; and second signal processing means for providing electrical signals to the display means to form a visible representation on the viewing screen of said electrical measurements derived in the zone of the borehole 55 represented by the index marks, the first and second signal processing means being responsive to movement of the logging means through the borehole to produce correlative movement of the index marks and visible representation respectively on the view-60 ing screen.