FR2497578A1 - Determining location of seismic cable trailing behind ship - by emitting signals from ship and recording and mixing reflected signals - Google Patents

Abstract

Seismic data are collected and recorded e.g. by lowering a probe down a drilled hole. The data are e.g. the amplitude, frequency, phase and momentary speed of seismic energy. The recorded data are fed into a computer, so they can be quantified as an image raster, the parameters of the latter being fed into a memoery bank. The memory bank is used to feed an image process computer which produces images which are easy to identify due to the interaction of colours. The images are displayed on a TV screen. The data pref. consists of three seismic energy parameters so the image process computer can treat three colours, viz. red, blue and green. Used for easy identification of subterranean strata, esp. oil below the seabed.

Description

INTERACTIVE ANALYSIS METHOD AND SYSTEM
IN COLOR OF GEOPHYSICAL DATA
The present invention relates to the presentation of geophysical data in a form facilitating interpretation, and it relates more particularly, but not in a limiting manner, to an improved method of interactive analysis and presentation of multiple properties linked to geophysical data.

 We find, in the prior art, isolated examples of attempts made to improve the possibilities of interpretation offered by data such as seismic data, by the use of an analysis with variable colors. US Patent 2,944,620 describes a frequency diversity technique in which frequencies are assigned to data in accordance with intrinsic values in the thickness direction of the strata, and selected colors are used in association with the frequency bands to present the amount of energy in a frequency band present on the representation.

This technique effectively attempts to isolate particular interesting frequency bands, after which the output information is presented by assigning selected colors to the frequency bands, so as to give an indication of basic energy. U.S. Patent 3,662,325 describes the selection of one or more intrinsic or extrinsic values of seismic data and the assignment of a selected color to each of these values. Then, the data values are presented in color and superimposed with color intensities which vary directly depending on the data values of intrinsic or extrinsic properties, to which a selected color is assigned.

 The invention relates to improvements in the presentation in color of selected geophysical data values, so as to obtain a final output presentation containing more information for the geophysicist who has to interpret it. According to the invention, one or more attributes consisting of parameters of geophysical data are processed, such as for example seismic data, data for exploration and delimitation of an ore deposit, etc., and each set is converted data in a unitary array of two-dimensional picture elements for visual presentation. The individual picture element arrays then exhibit the selected property of the data by varying coverage and intensity of the picture elements. 'images that are related to the particular property, with a representation according to a selected mixture of colors. We can then combine several properties on top of each other, each in a selected or different color or mixture of colors, and vary them empirically to achieve interactive colored effects which are decisive with regard to certain geophysical properties and trends.

 The invention therefore makes it possible to carry out an interactive presentation method in color which provides more information to the person responsible for the interpretation.

 The invention also aims to provide a color analysis tool of great flexibility which can be used with various forms of geophysical data linked in dimensional fashion.

 The invention also makes it possible to produce a color analysis tool having greater flexibility of use and allocation of the interpretation functions.

 Another object of the invention is to provide a method of interpreting seismic data in which the operator can change the output presentation, both dynamically and interactively, in order to empirically achieve the best presentation of the data. .

 The invention t all it er.fp to a method allowing to simultaneously present several measurable properties of geophysical data, while allowing the person responsible for the interpretation to adjust interactively and to visualize a simultaneous variation of several variables, by establishing an empirical link between such effects and the presence of hydrocarbons or minerals, or other interesting indicators.

 One aspect of the invention relates to a method for interactive color analysis of geophysical data, in order to allow an improvement in the possibilities of interpretation, characterized in that: geophysical data having a known spatial relationship with respect to a plane are determined selected exploration; processing this input data to determine at least one selected attribute of the data; the processed data is quantified, in the form of an image frame in which the attribute or attributes of the data are represented as a function of both the area and the intensity, and the attribute (s) is presented data in the form of an image frame, with selected colors.

 Another aspect of the invention relates to a method of processing seismic data to obtain an improved representation for a selective interpretation, characterized in that: the seismic data is processed on a selected part of a seismic section to produce a first attribute-weighted output grid for seismic data; processing the seismic data on the selected portion of the seismic section to produce a second output grid weighted by an attribute for the seismic data; and the output grids of attribute weighted seismic data are superimposed, the first and second output grids weighted by attributes being applied, with the best empirical variation, to different primary colors selected from a presentation monitor in color.

 Another aspect of the invention relates to a method for interpreting hydrocarbon indicators using several linked seismic sections corresponding to three-dimensional seismic trace data, characterized in that: the seismic data are processed to produce several output attributes of this data for a selected plane, in the three-dimensional seismic trace data; each of the different output attributes is converted into an image frame to produce a uniform output grid in which the seismic data are represented as a function of the area and the color intensity of the image elements; and these output attribute grids are presented in superpositioll with selected colors, each output attribute grid corresponding to a selected mixture of colors and to a selected intensity weighting.

 Another aspect of the invention relates to a geophysical data processing system of the two-coordinate type, intended to allow an improvement of the interpretation, characterized in that it comprises: means intended to memorize several records of the geophysical data , each of them being representative of an attribute of this data which consists of a selected parameter; means for converting each of the stored records into an image frame, to give a two-dimensional grid in which the indications of the individual records are represented by a characteristic number of grid elements and color level; and means for reproducing each of the converted recordings as an image frame, with a different color, and placing the reproduced recordings so as to make the grid elements coincide, in the form of a reproduction superimposed on several colors.

The invention will be better understood on reading the following description of an embodiment, given without limitation. The following description refers to the accompanying drawings in which
Figure 1 is a flow diagram illustrating the process for interactive color presentation of geophysical data
Figure 2 is a general block diagram showing the interconnection of the equipment used for the interactive color presentation
Figure 3 is a schematic representation showing three colored attributes of a seismic wave which are combined to give an interactive colored wave
Figure 4 is a block diagram of the equipment used for the implementation of interactive color representation
Figure 5 is a flow diagram of the grid program which is used to assign two-dimensional picture element values to selected geophysical data.
Figure 6 is an example of a typical seismic exploration section
Figure 7 is a red representation of selected parts of the seismic section of Figure 6
Figure 8 is a green representation of selected parts of the seismic section of Figure 6
Figure 9 is a blue representation of selected parts of the seismic section of Figure 6
Figure 10 is a three-color representation of selected parts of the seismic section of Figure 6
Figure 11 shows a second characteristic type seismic exploration section
FIG. 12 is a three-color representation of a selected part of the seismic section of FIG. 11, showing the formation of the image elements
Figure 13 is a characteristic shape of a terrain model formed from three-dimensional seismic data
Figure 14 is a three-dimensional representation in three colors
Figure 15 is a representative cross-section showing a characteristic technique for delimiting an ore deposit
Figure 16 is a color representation of gamma data obtained by delineation drilling for a known ore deposit; and
Figure 17 is an interactive color representation of gamma and resistivity data for the same ore deposit.

 We will now consider FIG. 1, noting that the technique of the invention allows the person responsible for interpretation to more easily grasp the simultaneous variation of several variables corresponding to geophysical data, so as to establish the link between the effects observed and the existence of hydrocarbons or minerals, or other geophysical indicators of interest.

More specifically, the method relates to the quantification of one or more geophysical variables and the assignment to the quantified area, associated with corresponding data values, of a gradation which consists of a certain function of the variable. The resulting quantized data is then loaded into a digital regeneration memory of a color presentation system, as will be described later in more detail, and each data variable is assigned to a selected channel of the regeneration memory, with as many variables or channels as there are in the total data compilation. The regeneration memory channel can then be applied interactively to the red, green and / or blue color cannons of a television monitor. color of conventional type, and the data can still be varied by means of tables to consult, combinational logic circuits and other function processing present in the image processing computer, mentioned below.

 As shown in Figure 1, the selected geophysical track data, as compiled in the field for the particular exploration operation, is available on a tape 10. These track data recorded on tape, for example on tape 10, are compiled according to a procedure, conventional in seismic and other mineral prospecting operations, and they are readily available, in pre-processed and digitized form, for use in the invention. The strip 10 containing the geophysical data is then used as input medium for a selected form of computer 12 intended to subject the information to a conversion in the form of an image frame, as will be described below. in more detail. The output data in frame form, which correspond to the selected attributes or properties of the data, is then presented as output to be recorded on one or more attribute bands 14, 16 and 18, and this data are then ready to be introduced interactively in the presentation device.

The attributes selected can be any parameters or property values selected from the input data. For example, in the case of entering seismic data, the variables could be amplitude, frequency, envelope (energy), phase, instantaneous speed, etc.

 The individual streams of data values or attributes, converted to an image frame, can then be selectively applied to the regeneration memories 21, 22 and 23 of the interactive color controller 24. The output signals from the memories regeneration 21-23 are then processed by the image computer 25 and are applied to a display device, of the monitor type, 26. The monitor 26 and the application of data in the form of an image frame which come from regeneration memories 21-23 are also subject to the choices made by the operator, as will be described below in more detail.

Considering FIG. 2, it is noted that the technique of the invention is implemented by way of example using a magnetic tape unwinder 28 of the brand
Hewlett-Packard which receives the pre-processed geophysical data as input, since it works in conjunction with a conventional disk memory 30 (Hewlett-Packard) and an input keyboard 32 (Hewlett-Packard). The magnetic tape unwinder 28 also works in association with a computer 34 which is programmed to perform conversion as an image frame in order to put the data in a particular format for the rest of the image presentation system. The computer for converting into an image frame 34 is the model computer 174, called CYBER, from the firm Control Data Corporation. This computer retransmits the information, converted into a frame, to the magnetic tape unwinder 28. image, which corresponds to the selected data parameters, for recall to the disk memory 30. The output signal from the disk memory 30 is applied to the interactive color controller 24, which is the computer
Image Process Computer, model 70, from the firm International
Imaging Systems, which operates in conjunction with a conventional color monitor 38 and a rolling ball pointer 40. The color monitor with the rolling ball may for example be of the type 5411 manufactured by the company CONRAC, Covina, California.

 FIG. 3 represents a simplified form of a presentation with variable zones in which the traces are tinted with an intensity which is proportional to the attributes. Thus, and by way of example, the seismic data signals 42, 44 and 46 can respectively represent the amplitude of the seismic energy, the instantaneous frequency and the approximate speed in an interval, for a series of selected events. Thus, each image element in each tinted zone of the signals 42-46 is a function of the respective parameter of the seismic energy.

 It should also be noted that the individual picture elements, which normally have a square or rectangular shape, have a high resolution in this representation, but, if the resolution was reduced to two or three picture elements for the maximum amplitude, there would be a slope with two or three steps, for each of the tinted areas of maximum amplitude, and a smaller number of indications of picture elements for the areas of lower amplitude. Thus, the amplitude function code 42 represents a dark red hue 48 followed by a light red hue 50 and by a medium red hue 52. The data or the instantaneous frequency curve, 44, would be converted into a frame using a light blue tint 54, followed by a dark blue tint 56 and a medium blue tint 58.Finally, the information in the green canon of curve 46, converted into a frame, would present a combination of elements of dark green image 60, followed by a dark green maximum 62 of lower amplitude and by a light green maximum 64. The colored combination of the three color lines of attributes 42, 44 and 46 would then be reproduced in the form of the network of picture elements 66, with a configuration of yellow picture elements 68, a configuration of purple picture elements 70 and a configuration of white picture elements 72.

 FIG. 4 shows the way in which three or more of the selected digital variables can be loaded into the regeneration memory of the color controller 24, then subject these variables to an interactive coloring performed by the operator who performs the interpretation, by means of a transformation such as a linear projection by rolling ball, an allocation of space with variable colors, etc. Thus, the regeneration memories receive, as input, information coming, for example, from an amplitude section converted into a frame, 74, from a phase section converted into a frame, 76, from a velocity section converted into a frame, 78, and one or more additional sections, if desired, which give information converted into a frame, which is illustrated by position 80. In this case, consider seismic section trace information which is preprocessed, by conventional seismic techniques, for the respective attributes and then converted into a frame by the computer 34 (FIG. 2), so as to be placed functionally in the memory at disk 34, in the form of digital attribute data tapes converted into a frame.

 The attribute data converted into a frame 74-80 are then available in the display memory 82, the display memory 84, the display memory 86 and the display memory 88 (regeneration memories) of the color controller 24. The color controller 24 also includes lookup tables 90, 92, 94, 96 which receive attribute data as input from the respective display memories 82-88. Consult tables 90-96 operate under operator control, in association with a trackball 40, so as to apply linear or non-linear transformations, in order to apply selective weighting to selected attribute data. At the same time, under the control of the front panel, the output signals from the respective look-up tables 90-96 are applied to circuits selected from the combination logic circuit for red, 100, the combination logic circuit for green. 102 and the combination logic circuit for blue 104. The combination logic circuits 100 104, for the respective primary colors, are also located in the image computer and their respective output signals are then applied to the television monitor. color 38 for the final presentation of the interactive color image, in the form of a frame.

 The conversion of selected cuts in the form of frames is accomplished in the computer 34 which is programmed so as to execute the functions represented by the flowchart of FIG. 5. It should be noted that this constitutes only one of the conversion programs in the form of a frame which can be used for converting the sections in the form of a frame. In fact, the screen is seen in the form of a grid of 512 x 512 elements and a selected part of a seismic section is placed superimposed on the grid by introducing, in the regeneration memories 36, scans horizontal lines that contain numbers representing levels of color for one of the selected attributes, or seismic properties, of the section. The numbers will be in the area which is defined by the zero liger and by the crests and / or troughs of the individual seismic traces. The horizontal scans then appear one by one, starting from the top of the screen, when the moment corresponding to the cut in question arrives, in the vertical direction. Up to 510 traces can be presented simultaneously and the distar.ce between the traces can be varied as well as the maximum horizontal displacement for the peak amplitude, by introducing the processing conditions.

 For example, to present the relative amplitude of a section formed by seismic traces, the maximum amplitude of the section is first determined. We then associate with each successive amplitude a color level ranging from 0 to 255. We perform a level of 255 at the absolute value of the maximum amplitude and we assign to the other amplitudes color levels which are defined with respect to the maximum either of the complete section, ie of the part of a seismic section which is presented. The amplitude values of the traces are then converted into values representing the grid or image elements on the screen.

 Thus, firstly, successively, the positions of the zero crossings are determined along each of the respective seismic traces of the section. The maximum color level (or the minimum level in the case of a dip) is determined between each pair of zero crossings. This is done over the entire section so that each sample in the section has two values associated with it, that is, the amplitude in grid elements and a color level. Vertical scans are then produced one by one, considering the seismic section as a grid, with the Strong time in the vertical direction. The far right scan is produced by exploring the amplitude of the traces to determine if a trace has amplitudes that fall into this vertical grid element, then taking the corresponding color level for that amplitude and placing it in the sweep. The spacing between traces and the number of grid elements over which a trace can extend determines the number of traces that must be examined for each scan. We can imagine that when a scan is finished, it is eliminated from the section by the right, after which the next scan is constructed.

 Considering more particularly FIG. 5, it is noted that the computer is initialized and receives as input the information concerning the particular seismic section to be interpreted, in step 110. In the next step 112 of the organigranin the program for 1 '9rairteur calculates 1' attr1.l 'selected, that is to say the amp-e-relative in the case of the example above, and in step 114 of the flowchart the program assigns color codes to network values and converts all network values to picture elements.

The color codes and the image elements for the input network are then presented as output, in step 116, and in a decision step 118, the program asks whether or not there is a network of additional entry for total data. If the answer is yes, the program starts the cycle again and the immediately following network of numerical values is received at input step 110, for interpretation, calculation, etc. All the counters and all the tables of the system are initialized in step 120.

 In step 122, the program then reads all values of picture elements and color for the network as defined. Decision step 124 restarts the operation of reading the image element and color values if additional networks remain necessary to fill the first image scan.

When all of the networks for a scan have been read, the flowchart step 126 determines the recording of the color values for the scan. In steps of flowcharts 128 and 130, the program writes the scan to a file and increments the tables. At decision step 132, the program asks whether all the scans have been completed or not. If the answer is no, an affirmative indication is applied in flow chart step 134 to call the color and picture element values for the next network. If the values of the following network are necessary, the affirmative indication directed to step 136 asks if there are additional steps and step 138 reads and saves the established tables. The recycling of the program is accomplished from a point 140 towards a decision step 142 intended to determine whether the networks are finished and, if so, step 144 causes the headings of the tables to go up one row, leaving the upper heading. The program then returns to steps 126-132 which have the function of writing the scans in a file and, when the decision step 132 no longer requires scans, the image, converted into a frame, is presented as an output. to be entered into the regeneration memory of the image computer.

 Returning to FIG. 4, it is noted that the operator of the image computer exercises manual control over the mixing of colors and has the possibility of changing the total contrast of the output presentation. Thus, the operator can exercise a command from the keyboard 32, the rolling ball 40 and the commands from the front panel of the computer, so as to change the presentation both dynamically and interactively, to give the better presentation from the point of view of interpretation. Adjustments are made empirically, changing the presentation of the data of the individual attributes, to finally arrive at the best presentation. Thus, the operator can use the keyboard or the trackball to obtain the best mixture of colors for each attribute, by proceeding interactively; that is, the application of a selected percentage of each attribute to each color, from a pure color to a selected mixture.

Once the operator has obtained a desired mixture of colors, he can adjust the contrast relative to the hue of each color, individually or collectively. The keyboard command changes the functions of the tables to consult 90-96, i.e. the linear, non-linear modes, etc., so as to be able to increase or decrease the contrast relative to the hues in a manner selected for known amplitude ranges of the input data.

 FIG. 6 represents a characteristic seismic section 150 which has been chosen for the purpose of illustration.

Section 150 is a stacked linear information exploration section corresponding to a common point of depth which shows the seismic energy by descending vertically to a depth just below three seconds of propagation time, while the horizontal progression indicates the successive firing points along a line of exploration of 13 or 16 km in length, designated by the units 0-170. This section was chosen because it shows two existing productive wells that were drilled at approximately locations 152 and 154. The producing strata for well 152 are in the net seismic indication, in zone 156, while the producing zone for well 154 is indicated by the meeting of seismic events, in zone 158.We then took the vertical end comprising zones 156 and 158, as indicated generally by the horizontal braces 160 and 162, to separately convert to a raster and an interactive color exam.

 FIG. 7 represents, in black and white reproduction, a red color image 164 of the selected sections 160 and 162. Thus, the red image 164 represents a selected attribute of the seismic sections 160 and 162, applied to the red channel of the monitor in color 38, with presentation in the form of image elements or grid. In the actual photographic reproduction, the black parts of FIG. 7 are reproduced exactly, while the white parts of FIG. 7 are in brilliant red on the representation made on the television monitor 38. The reproduction 166 of FIG. 8 shows the same selected sections 160 and 162, but with a selected attribute different from this energy, in accordance with what the green channel of the television monitor reproduces 38. In real photography, the black parts are black and the white parts of the figure 8 are green. FIG. 9 then shows the reproduction of a photograph showing a blue image 168, the black being black and the white of FIG. 9 being in reality blue, and this image shows the same zones and the seismic sections 160 and 162 for a third attribute of the sections, corresponding to their response to seismic energy.

 Figure 10 shows the three-color combination of the red, green and blue reproductions 164-168, produced for each of the three distinct attributes of seismic energy within selected sections 160 and 162.

In the three-color image 170, most of the black in Figure 10 is colored dark blue, while the white in Figure 10 ranges from white to yellow and dark gray-blue becoming lighter. In the interpretation of seismic explorations, the practice is to look for "bright spots", as indicators of possible producing zones. The indications corresponding to the two producing zones 156 and 158 are extremely bright and include a very important white indication in which are scattered some indications of dark grayish blue color. Zone 156 is white at the upper and lower extremities, with a large central part of a very forced color which indicates the fact, confirmed later by knowledge of the well itself, that the producing zone is a highly saturated zone. of water. Similarly, zone 158 gives strong white indications at the upper and lower part, with a much smaller intermediate part of dark greyish blue color, and it turns out that the well associated with zone 158 was a good producing well.

 Figure 11 shows a reproduction of another seismic section 172 made along an exploration line indicated generally by arrow 174, with recording of the seismic energy to a depth of about four seconds propagation time. The presentation is made up of the common depth point information, represented in the form of a gray wavy trace, and it gives a good indication of zones containing hydrocarbons, in itself and by itself.

However, the selected part inside the square 176 was subjected to an interactive analysis in three colors, by assigning to the colors the selected attributes (envelope, amplitude and frequency). FIG. 12 is a reproduction 178 of the information in the form of a three-color image frame presented by the television monitor 38 for this area 176 (FIG. 11), after interactive analysis. Reproduction 178 is of particular interest in that it offers good resolution, which makes the structure of event image elements and the concentration of vertical scanning apparent. Dark events, like the one appearing in 180, are dark blue in color
The general background, as in 182, is of a medium green color.

A certain effect of coloring in pink manifests itself next to the white dots, and it is clearly seen that white dots, such as that indicated in 184, indicate the existence of zones which are probably good zones producing hydrocarbons. The areas on the left are likely areas of petroleum and the areas on the right have gray in white, which strongly suggests that these are gas producing areas.

 We will now consider FIG. 13 which represents a three-dimensional terrain model constructed from conventional three-dimensional seismic information. Indeed, it is common practice at present to carry out an exploration according to a certain number of parallel lines, which a numerical treatment allows - then to place according to a three-dimensional relation and to present in the form of a section having any orientation selected. One could for example carry out a certain number of explorations such as that represented by the section 172 of FIG. 11, in the same direction, but by undoing each relative to the others by a predetermined distance, for example 65 m, 130 m , 260 m, etc. We can then reproduce such an assembly of data in the form of the three-dimensional section in Figure 13 which shows the vertical data with the classic wavy and grayed traces, but with the horizontal data in the form of a presentation with variable areas at one depth of cut corresponding to a selected time. The iso-time model 181 is cut so as to show the structure of the terrain at 2500 ms.

 The information of a three-dimensional model 181 can also be the subject of an interactive analysis in color to provide more information allowing the interpretation of the terrain model. Figure 14 shows a three-color image 182 of a section corresponding to a time of 2.5 s, in association with the underlying strata. The actual colors as reproduced on the television monitor are marked in Figure 14 by the first letter of the respective colors cyan, yellow, white and magenta. The vertical depth plane 184 is largely magenta but it also reveals the associated strata of cyan, white and yellow. The isotemps section plan at 2.5 s and its color contours effectively allow a classification of the geological age. individual strata, as well as the delimitation of producer sand in the white areas. It is possible to make color copies, on paper, of three-dimensional data in the form of slices, with a representation by bars with variable density, by converting the output information of the image calculator 25 according to a mode suitable for the application to a plotter from the Applicon brand, of the classic type.

 A large amount of spatially related data can thus be quantified and subjected to interactive color analysis in accordance with the method of the invention. The selected attributes that are used in the analysis can be related to their type. However, this is not necessary, since data from various sources can be combined for a given spatial volume for interactive analysis. For example, for a given terrestrial prospecting area, it may be desirable to analyze several attributes of seismic data with a linked attribute, obtained for example from a magnetotelluric exploration or by induced polarization, or from logging data which can exist in the prospecting area.

 The interactive color analysis according to the invention can be accomplished with many different forms of data. In addition to the seismic data considered previously by way of example, it is desirable to consider simultaneously several data attributes which result from explorations and from delimitations or yields from production drilling. This is particularly true for uranium ore deposits and oil fields with a high density of drilling, in which there is a dense network of data, from various borehole logs. For example, in a characteristic uranium ore deposit, there may be several thousand holes with a pitch of 15 m. For each of these holes, logging operations are carried out with well-known type instruments descending into the drilling, to determine parameters such as spontaneous potential, natural gamma radiation, resistance at a single point or resistivity, density, etc. In recent years, the current practice has been to record the variable or attribute haqe values on magnetic tape for each interval of approximately 15 cm in depth. This provides a huge source of data for the exploration geologist and the interactive color analysis now allows a complete interpretation of this data. The quantified color presentation of the values recorded in the boreholes and recorded for the various instruments can indicate the type of rock and the degree of uranium mineralization, as well as the presence of fluid in a formation and oil saturation.

 We will now consider Figure 15 which schematically shows a partial section of land 190 likely to be the subject of a drilling delimitation of a uranium deposit. It is easy to see, however, that the method could just as easily be applied to any form of logging data. The section of land 190 comprises a certain number of holes 192 which are formed from the surface 194 and which descend parallel to each other in the field 196. We then lower logging instruments into each of the holes 192, we record on log tape the log data in the form of traces for the respective parameters, and they are converted into digital form for application to the computer 12, with a view to conversion into the form of an image frame. zone of strong metallization in uranium, the recording of natural gamma radiation has very high values, which means that the logarithm of the values of gamma radiation is calculated. Each trace or recording has a variable starting depth, depending on the altitude of the point on the ground from which the sounding starts, so that each recording of spontaneous potential, natural gamma radiation, resistivity, density and n ' no matter what additional attributes, must be corrected to be brought back to a certain common altitude, such as for example the dotted line 198, chosen from the data of the particular site.

In summary, from the raw data collected in the field, the following parameters can be calculated by processing the data and bringing them back to a common altitude
1) logarithm of natural gamma radiation
2) resistance
3) change in resistance depending on the
depth (QR / 6D)
4) density
5) spontaneous potential
Traces of data for one or more of the above attributes can then be converted to a frame and used as input for interactive color processing and display, either as a vertical section, if we have three-dimensional data, either in the form of a horizontal section corresponding to a certain altitude above sea level. Thus, if we are developing attribute traces for a particular altitude above sea level for several thousands of surveys, we can build a horizontal section showing the relationship of the three variables chosen in a horizontal plane.

 The color assigned to each attribute trace value can be determined from the maximum and minimum values of the resistance record, for example. We designate, for each amplitude value greater than the minimum value or "shale line", a color level between O and 225. The shale line is defined as being the minimum value on any trace of resistance complete, found in a survey, and it is possible to assign, to selected attribute variables, color levels determined by their amplitudes. These colors are then combined and presented with the television monitor and the image processing computer.

 FIG. 16 represents the interactive color response obtained from the attribute consisting in gamma radiation for a series of twelve soundings, for example similar to those represented in FIG. 15. Pseudo-colors have been assigned to the gamma radiation values from the darkest blue to pure white, passing through the reds, for increasing values of the intensity of gamma radiation. The vertical section 200 represents a linear section of data, associated with a selected altitude 202 and presented according to a depth coordinate 204. The bottom of the section 202 has a predominantly light magenta color (zones 206), and an ore deposit of uranium is bounded by a yellow formation 208, with white areas 210 showing a higher intensity of gamma radiation. Some slightly darker magenta bands, 212, indicate the dip of the rocks in the exploration area.

 FIG. 17 represents, for the same terrain, a section 214 resulting from the combination of the resistance and gamma radiation records. The gamma radiation recording indication is applied to the input of the red channel of the television monitor, while the resistance data is applied to the input of the blue and green channels of the monitor, and then weighted so interactive to give the optimal image of the cut. Here again, we can see the dip of the ground section, corresponding to a descent of the cuckoos when moving from left to right, as indicated by the upper band 216 (light pink). the section is in the form of dark pink zones 218, and the uranium ore deposit is clearly delimited in the white zones 220.

The interactive analysis method is extremely useful for the interpreter who has an abundance of recorded logging data. The process can naturally be applied in any field of geological science in which data collected in surveys is available, but we can cite some specific applications for prospecting for uranium.
a) lithological sections in color,
b) assimilation of data,
c) mine sequence maps (horizontal sections),
d) mineralization / ore density maps (cuts
horizontal),
e) interpretation of the environment of deposits, by
the use of ER / ED variations in a plan,
f) determination of the position of the "gamma front" in
drilling areas, to assist demarcation personnel
tion in determining the sonda locations
future ages (horizontal and vertical cuts), and
g) calculation of uranium ore reserves by the horn
input data from the recording
gamma radiation, to account for
dead time and factor k.

 In fact, interactive color analysis can be used with various forms of geophysical data, the essential condition being that the data can be organized in a representation by two-dimensional coordinates, suitable for presentation in the form of a grid.

 The interactive analysis can easily be extended to the fields of geology, geochemistry, the interpretation of oil well logging measurements, etc.

For example, in the geological field, it would be possible to facilitate the recognition of the representation of a lithological facies by loading, respectively in the different processing channels corresponding to a color, the particle size data, the quartz content and the unstable constituents. We could then code the shales in black, bring the depth along an axis of the color representation and make the color appear on the whole representation, or else, using separate bands, we could present a section established from information from correlated data from different wells. By further developing this information, a color diagram of lithological facies with direct application to exploration could be produced. In addition, isometric contours and projections developed by mapping and similar programs would improve the accuracy of the representation. Other variables that can be advantageously represented include: pore size, porosity, the presence of a cement and the density of fractures, as well as related factors.

 It should also be noted that qualitative estimates such as high, medium or low porosity can be translated into color intensity for use in individual interactive processing channels, and new variables such as the grain / matrix ratio.

 In the field of organic geochemistry, data indicating the types and levels, in percentage, of organic hydrocarbons and carbon, supplied by pyrolysis and chromatography devices, could be loaded into the processing channels corresponding to the colors. and mass spectometry. A type of organic matter, for example amorphous or woody, could also be the subject of a specific color treatment and be used in representations intended to allow a better interpretation of rock-store and rock-reservoir couples.

 In the electrophysical log analysis, many of the log responses could advantageously be processed interactively using the color channels. The resistivity, porosity and gamma radiation responses are obvious choices for this purpose, since they are likely to aid in the presentation of water saturation plots as a function of depth, as well as the estimation of petroleum. in place and the representation of capillary pressure and permeability. An interactive color representation can be very useful to allow a clearer discernment of the types of sand formations from the log responses, in particular for the gamma radiation responses. and the acoustic responses, as well as for the resistivity and porosity measurements, since these have definite lithological connotations and because the use of color makes it possible to interpret the complex combination of responses more easily than any other method existing today. The continuous information provided by a pendulum is similarly complex information and interactive color analysis considerably improves its interpretation.

 We have just described an original process for the interactive color analysis of associated types of data. The analysis technique offers a method by which an operator can continuously adjust converted input data in the form of an image frame or grid, by a selective mixture of colors and by a selective weighting of color intensity, from dewlap to obtain a presentation offering the best interpretation possibilities for all the data.

An experienced operator is able to analyze interactively all of the associated data attributes, by empirical adjustments, to arrive at a definitive representation of the particular properties considered.

 It goes without saying that numerous modifications can be made to the method and to the device described and shown, without going beyond the ambit of the invention.

 Finally, it will be noted that the object of the present invention is indeed a manner of operating, that is to say a process having an industrial character in its object (since it is situated in the field of prospecting), in its application ( because it comprises a series of concrete steps, mentioned in the description and materially executed) and in its results (by making it possible to achieve a very meaningful representation of the physical characteristics of a formation of terrains, hence an effect technique usable industriellemeng. The program and the computer that brings it into play are only used to control certain steps of the process and are not claimed in themselves.

Claims (25)

 1. A method of interactive color analysis of geophysical data, to allow an improvement in the possibilities of interpretation, characterized in that: geophysical data having a known spatial relationship with respect to a selected exploration plan are determined, these are processed input data for determining at least one selected attribute of the data; the processed data is quantified, in the form of an image frame, in which the attribute or attributes of the data are represented as a function of both the area and the intensity, and the one or more are presented data attributes in the form of an image frame, with selected colors.  2. Method according to claim 1, characterized in that the processing operation comprises the determination of three attributes of the input data.  3. Method according to claim 2, characterized in that the presentation operation comprises the presentation of each of the attribute data in the form of an image frame with a different selected color.  4. Method according to any one of claims 1 to 3, characterized in that the exploration plane selected is horizontal.  5. Method according to any one of claims 1 to 3, characterized in that the selected exploration plane is vertical.  6. Method according to any one of claims 1 to 5, characterized in that the quantization operation comprises the operation which consists in preselecting a non-linear transformation of the intensity level of the attribute or attributes of the data.  7. Method according to any one of claims 1 to 5, characterized in that the quantization operation comprises the operation which consists in preselecting a linear transformation of the intensity level of the attribute or attributes of the data.  8. Method according to claim 3, characterized in that the individual color representations are varied to empirically arrive at the best output representation.  9. Method according to claim 8, characterized in that the color mixture is varied between the three data attributes and a preselected color intensity transformation factor is introduced.  10. Method according to claim 3, characterized in that at least one additional attribute of the input data is determined and introduced; and this additional attribute or attributes of data are selectively mixed with the three attributes of the input data.  11. Method according to claim 9, characterized in that the selected exploration plane is horizontal.  12. Method according to claim 9, characterized in that the selected exploration plane is vertical.  13. Seismic data processing method to obtain an improved representation for a selective interpretation, characterized in that the seismic data are not processed on a selected part of a seismic section to produce a first output grid weighted by a attribute, for seismic data; processing the seismic data on the selected part of the seismic section to produce a second output grid weighted by an attribute for the seismic data; and the output grids of attribute weighted seismic data are superimposed, the first and second output grids weighted by attributes being applied, with the best empirical variation to different primary colors selected from a color presentation monitor. .  1 Method according to claim 13, characterized in that, in addition, the seismic data is processed on a selected part of a seismic section to generate a third output grid weighted by an attribute of the seismic data; and this third output grid weighted by an attribute is represented in superposition with the first and second output grids weighted by an attribute.  15. The method of claim 13, characterized in that, in addition, the seismic data is processed on a selected part of a seismic section to produce at least one additional output grid weighted by an attribute of the seismic data; and we represent this grid or these additional output grids weighted by an attribute, superimposed on the first and second output grids weighted by an attribute.  16. Method for interpreting hydrocarbon indicators using seismic cut trace data, characterized in that the seismic cut trace data are processed to produce several versions of this data converted into an image frame , each of these versions being weighted in accordance with an attribute corresponding to a different and selected parameter of the data, and the different versions of the seismic trace data are represented in superposition, by applying each version of the data with a selected color whose l intensity proportional to the respective attribute corresponding to a parameter.  17. The method of claim 16, characterized in that the selected colors are the three primary colors.  18. Method according to any one of claims 16 or 17, characterized in that the processing comprises the operation which consists in producing the data for each version by representing the trace data by means of uniform grid elements arranged relative to at each zero crossing of the traces.  19. The method of claim 18, characterized in that the processing further comprises the operation which consists in varying the color intensity of the trace data as a function of the attribute corresponding to a parameter and in defining such a level of color for each grid element of the trace data, for each version.  20. The method of claim 19, characterized in that the operation of varying the color intensity comprises the operation of preselecting a non-linear transformation of the color level of the trace data.  21. The method of claim 19, characterized in that the operation of varying the color intensity includes the operation of preselecting a linear transformation of the color level of. trace data.  22. A method of interpreting hydrocarbon indicators using several linked seismic sections corresponding to three-dimensional seismic trace data, characterized in that: the seismic data are processed to produce several output attributes of these data for a selected plane, in three-dimensional seismic trace data; each of the different output attributes is converted into an image frame to produce a uniform output grid in which the seismic data are represented as a function of the area and the color intensity of the image elements and we present these output attribute grids superimposed with selected colors, each output attribute grid corresponding to a selected mixture of colors and to a selected intensity weighting.  23. The method of claim 22, characterized in that the selected colors are the three primary colors.  24. The method of claim 23, characterized in that a non-linear transformation is preselected for each color intensity for the attribute output grids.  25. Method according to claim 23, characterized in that a linear transformation is preselected for each color intensity of the attribute output grids.  26. A two-coordinate type geophysical data processing system, intended to allow an improvement of the interpretation, characterized in that it comprises: means (10) intended to memorize several recordings of the geophysical data, each of them being representative of an attribute of this data which consists of a selected parameter; means (12) for converting each of the stored records to an image frame, to give a two-dimensional grid in which the indications of the individual records are represented by a characteristic number of grid elements and color level ; and means (26) for reproducing each of the converted recordings as an image frame, with a different color, and placing the reproduced recordings so as to make the grid elements coincide, in the form of a reproduction in superimposition of several colors.