CA1185350A - Method and apparatus for obtaining a display of a characteristic of the periphery of a borehole - Google Patents
Method and apparatus for obtaining a display of a characteristic of the periphery of a boreholeInfo
- Publication number
- CA1185350A CA1185350A CA000386848A CA386848A CA1185350A CA 1185350 A CA1185350 A CA 1185350A CA 000386848 A CA000386848 A CA 000386848A CA 386848 A CA386848 A CA 386848A CA 1185350 A CA1185350 A CA 1185350A
- Authority
- CA
- Canada
- Prior art keywords
- periphery
- producing
- cement
- casing
- shading
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/40—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging
- G01V1/44—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging using generators and receivers in the same well
- G01V1/48—Processing data
- G01V1/50—Analysing data
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/005—Monitoring or checking of cementation quality or level
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V11/00—Prospecting or detecting by methods combining techniques covered by two or more of main groups G01V1/00 - G01V9/00
- G01V11/002—Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant
Abstract
ABSTRACT OF THE DISCLOSURE
In methods and apparatus for producing a film record or other graphic display of the bonding quality of the cement in a cased borehole, a plurality of measurement signals respectively representative of the bonding quality of the cement to the casing for portions of the casing distributed around the borehole are produced. These measurement signals are converted into respective quantified signals having a limited number of possible values. A shading code is selected for each such measurement signal based on the quantified value thereof. For each depth level, a line modulated by the selected shading codes is displayed, producing over a plurality of depth levels parallel longitudinal bands. Each band comprises a succession of shaded zones.
In methods and apparatus for producing a film record or other graphic display of the bonding quality of the cement in a cased borehole, a plurality of measurement signals respectively representative of the bonding quality of the cement to the casing for portions of the casing distributed around the borehole are produced. These measurement signals are converted into respective quantified signals having a limited number of possible values. A shading code is selected for each such measurement signal based on the quantified value thereof. For each depth level, a line modulated by the selected shading codes is displayed, producing over a plurality of depth levels parallel longitudinal bands. Each band comprises a succession of shaded zones.
Description
3~
METHOD AND APPARATUS FOR OBIAINING A DISPLAY
OF A CIIARACTERISTIC OF THE PERIPHERY OF A BOREHOLE
BACKGROUND _ TIIE INVENTION
This invention relates to displays for the study of a characteristic associated with a borehole, and more particularly to a method and apparatus for producing a graphic recording of a characteristic of the periphery of a bore-hole, such as for example the quality of the cement bond around a casing.
Oil well completion operations Eor initial production begin with the placement of a casing and the injection of cement between the casing and the surrounding earth formations. The main function of the cement is to isolate the formations so as to avoid the flow of fluids along the casing between aquifer layers and other formations containing hydrocarbons. It is thus very important to know the bonding quality of the cement around the casing.
A logging apparatus for obtaining this information is described in U.S. Patent No. ~,255,798, issued March 10, 1981 to Havira. In one embodiment, the downhole apparatus comprises several (for example, eight) acoustic trans-ducers positioned helically around the body member for the inspection of the entire casing periphery. A signal is generated that is representative of the bonding quality of the cement on the part of the casing corresponding to the exploration field of this transducer.
One advantage of this apparatus is that it allows the study of the bonding of the cement on surfaces of limited size on the periphery of the cas-ing, thereby making it possible to identify communication channels between certain formations even when the average quality of the cement appears to be good. One of the difficulties encountered has to do with the recording of the results. In fact, if a conventional plot on a film medium is made of the output signal as a function of depth, a number of 35~
curves are obtained which are not directly utilizable and which are often even difficult to separate from each other. In addition, it is desirable to provide other data, for example the average quality of the cement, thus further compli-cating the representation.
Logging techniques for furnishing a continuous visual representation of the wall of the borehole or of the formation layers around it are described in Canadian Patent No. 685,727 ~Mann ~ Threadgold). Signals coming from current electrodes are used for the intensity modulation of an oscilloscope. The pur-pose is to obtain an image of the limits between the formation layers in order to deduce the dip; accordingly, the boundaries between the changes in the record-ing shade give the desired information of the layer limits. The shades them-selves, which correspond to resistivity values, are strictly speaking of no interest. In addition, a spot whose intensity is modulated in proportion to the amplitude of the signal does not give a satisfac-tory distribution of shades for the objects of this invention.
SUMMARY OF THE INVENTION
-The object of this invention therefore is to provide a graphic display or recording of the bonding quality of the cement around a casing, in which the periphery of the casing is represented in the form of a developed area whose shade in each zone indicates this bonding quality in a satisEactory manner.
Another object of the invention is to provide a method and an appa-ratus for obtaining such a display or recording.
The aforementioned and other objects are achieved by the present inven-tion in accordance with a method for producing a graphic display, such as for example a film record, of a characteristic of the periphery of a longitudinal cavity passing through earth formations, such as for example the bonding quality of the cement in a cased borehole. A plurality of measurement signals respec-i3~
tively representative of the characteristic for portions of the periphery distri-buted around the cavity are produced. These measurement signals are converted into respective quantified signals having a limited number of possible values.
A shading code is selected for each such measurement signal based on the quanti-fied value thereof. For each depth level, a line modulated by the selected shad-ing codes is displayed, producing over a plurality of depth levels parallel longitudinal bands. Each band comprises a succession of shaded zones.
A variation of this method includes the additional steps of producing a signal representative of the position associated with a predetermined one of the measurement signals, and selecting longitudinal positions for displaying the shaded zones of the parallel bands.
The aforementioned and other objects are achieved by the present inven-tion in accordance with an apparatus for producing a graphic display, such as for example a film record, of a characteristic of the periphery of a longitudi-nal cavity passing through earth formations, such as for example the bonding quality of the cement in a cased borehole. Measuring means, including a plural-ity of transducers, is provided for producing, at different depth levels, a plurality of measurement signals respectively representative of said character-istic for portions of the periphery distributed around the cavity. Processing means, comprising memory means and shading code selecting means, is provided for converting said measurement signals into respective qualified signals having a limited number of possible values. Means is provided for displaying a line modu-lated by the selected shading codes, producing over a plurality of depth levels parallel longitudinal bands. Each band comprises a succession of shaded zones.
A variation of this apparatus further comprises means for producing a signal representative of the position of at least a predetermined one of the transducers, and means responsive to this position signal for selecting longitu-~, 53'j~
dinal positions for displaying the shades zones of the bands at each respectivedepth level.
Other objects, featu-res, and characteristics of the present invention will become apparent upon consideration of the following Detailed Description and the appended Claims, with reference to the accompanying Drawings, all of which are part of this Specification.
BRIEF DESCRIPTION OF Tt-lE DRAWINGS
In the drawings, where like reference characters indicate like ele-ments, Figure 1 is a partly block, partly pictoral schematic diagram of an apparatus in accordance with the present invention, shown inserted in a cased cemented borehole;
Figure 2 is a block schematic diagram of the optical recorder of Figure l;
Figure 3 is a flowchart representing a sequence of stages in accord-ance with the present invention, for execution by the apparatus of Figure 1, and more particularly by the computer shown in Figure l;
Figure 4 is a flowchart representing a process stage of Figure 3 in greater detail; and Figure 5 is an illustration of a display on a recording medium, ob-tained in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figure 1, an acoustic logging apparatus for studying the quality of the cement comprises a downhole apparatus lO suspended in a borehole 11 at the end of a mul*i-conductor çable 12. The borehole 11 which goes through formations 13 is equipped with a casing 14 surrounded by cement 15 injected be-tween this casing and the formations 13. This logging apparatus is described in _~_ greater detail in the above-mentioned U.S. Patent to Havira. In general, how-ever, the downhole apparatus 10 includes an elongated body member 16 maintained in the axis of the casing by upper 17 and ]ower 18 centering devices. On the body member are fixed eight acoustic transducers 20, Tl to T8, arranged heli-cally so as to inspect portions of casing distributed regularly on the periphery of the borehole. In the embodiment of the figure, the position of a transducer is deduced from the position of the preceding one by a ~5 rotation around the axis of the body member. Other arrangements are obviously possible with differ-ent numbers of transducers and/or different arrangements of these transducers around the borehole. Each transducer 20 (Tn) is controlled for the transmission, in a radial direction, of acoustic pulses of short duration whose spectrum has an average frequency of about 500 kHz. Each transmitted pulse is reflected by the different interfaces it encounters to yield an echo signal detected by the same transducer T which then operates as a receiver. This detected signal in-cludes aninitial segment coming from an initial reflection on the casing and a second segment corresponding to a reverberation within the casing.
Inside the body member are placed electronic circuits connected to the output o:E the transducers to generate raw signals in response to the detected echo signals. The first raw signals Wl for each transducer T are representa-tive of the maximum amplitude reached by the initial segment of each detectedsignal. Second raw signals W2n are obtained by rectifying and integrating the second segment, characterized as the reverberation segment, of each signal de-tected by each transducer T . Other raw signals can also be produced, for example the transi-t times ~t of the segments reflected on each transducer.
These raw signals for the eight transducers are converted into digital form and sent to the surface via transmission circuits connected to the conductors of the cable 12. Circuits for producing these raw signals are described in greater de-tail in the above-mentioned Havira Patent.
~ r-93t~
The conduc-tors of the cable 12 are connected on the surface to acquisi-tion circuit 22 which processes the transmission signals coming from the down-hole apparatus 10 and enters the raw signals Wl , W2 , ~t in a memory 23. The memory 23 is updated whenever signals are received, for example every 125 milli-seconds. A cable movement detection device, including a wheel 25 bearing tangen-tially on the cable, controls a depth pulse generator 26 which delivers a pulse whenever the cable is moved by a predetermined unit length. One thus obtains signals representative of the depth of the downhole apparatus 10.
The depth signals coming from the generator 26 are used by a computer 27 to perform a series of processing stages at each depth level. As an example, this series of stages can be carried out whenever the downhole apparatus is moved 5 cm. In other words, the interval between the depth levels examined suc-cessively is 5 cm.
The processing of the computer 27 furnishes a first set of output signals to a magnetic recorder 30 which records them in digital form, level by level, on magnetic tape. This magnetic recording makes it possible to use auto-matic data processing if desired. The computer 27 also furnishes, for each level, a second set of output signals to an optical recorder 31 which provides, on a film, a graphic recording particularly satisfactory for fast visual inter-pretation. In the example, the recorder is of the cathode-ray-tube type con-trolled by electronic circuits as described in U.S. Patent Numbers 3,986,163 and 4,010,476, issued to Elliott on October 12, 1976 and March 1, 1977 respectively.
Referring to Figure 2, which represents optical recorder 31 schematic-ally, a medium 33 consisting of a photographic film is moved in front of a cathode-ray-tube 34 to be exposed by the spot of this tube. The transverse posi-tion of the spot on the film is controlled by a scanning circuit 35 and its luminosity is controlled by an intensity circuit 36. The intensity control cir-3~
cuit 36 is synchronized with the scanning circuit to release the electron beamof the twbe in order to place points at predetermined transverse locations on the medium.
The obtained recording includes a classical part having a grid made up of transverse depth lines and longitudinal scale lines and curves which repre-sent on this grid the variations, indicated transversely, of certain output signals as a function of depth. This classical part is obtained by adding, in a combination circuit 37, signals coming from depth line circuit 40, scale line circuit 41, and plot circuit 42. These circuits are described in greater detail in the above-mentioned Elliott Patents.
The recorder 31 also includes a memory 43 containing a succession of binary digits capable of being read under the action of a control circuit 44.
The succession of binary digits is applied to the combination circuit 37 in syn-chronism with the transverse scanning of the film. The memory 43 is read from one end to the other during a transverse scan of the medium and the reading of each binary digit of value 1 actuates the entering of a black point on the film.
The memory 43 includes a number of binary digits chosen so as to be able to enter a point every 0.13 mm transversely on the film. A succession of "1"
digits corresponds to a continuous transverse black line. This memory 43 is particularly well suited to the recording of shades according to the invention as explained further below.
Referring to Figure 3, the processing stages carried out in the com-puter 27 are done level by level, i.e., in the example, every 5 cm (2") in res-ponse to the depth signals co~ing from the generator 26. The first stage con-sists in the depthwise correlation of the raw measurement signals (block 47).
To accomplish this, the raw measurement signals coming from each transducer T
of the downhole apparatus are stored in memory to be read after a period corres-~ ~5~35~3 ponding to the upward movement time of the lowest transducer Tl, up to the levelof the transducer examined T . This period thus depends on the speed of the downhole apparatus furnished by the depth pulse generator 26. The depthwise correlated raw measurements are then combined to obtain eight series of signals Ql to Q8 representative of -the bonding quality of the cement on portions of cas-ing distributed regularly around the borehole. For each transducer T a signal ~ ls calculated at each level ~block 48) in accordance with the ratio W2n/Wl of the raw signals coming from this transducer. As described in the above-mentioned Havira Patent, this ratio furnishes a signal representative of the bonding quality of the cement on the casing portion explored by the transducer Tn .
One also calculates (block 49) the average Q of the signals Q at each level and, if necessary, the fourth power Q4 of this average. The average Q
indicates the average bonding quality of the cement around the casing. The signal Q4 is of interest because it is close to the results obtained by appa-ratus used formerly for cement detection and allows a comparison with them.
The raw and calculated measurement signals are transmitted (block 50) to the magnetic recorder to be recorded in digital form level by level on mag-netic tape. The calculated signals moreover are processed ~block 51) to furnish an optical recording. The stages 47 to 51 are carried out level by level, i.e.
every S cm in depth (block 53) up to the last levels to be processed (block 52).
The processing stage 51 is represented in greater detail in Figure 4.
After a first initialization stage ~block 55), the first signal Q to be studied is selected ~block 56). In , first embodiment, one selects as the first signal studied the signal Ql coming from the first transducer Tl.
The signals studied Qn are selected in the order Ql to Q8 in order to match each recording band with the signals coming from a transducer. In the .i .:~
Q-~t~
following stage, the studied measurement signal Qn is converted into a quanti-fied signal having eight possible values made up of whole numbers from 0 to 7 (block 57). This stage includes a first scale changing operation for normaliz-ing the signal Q and bringing its variation range between zero and one, if such is not already the case. A second operation consists in multiplying by eight the normalized signal and in keeping only the whole part which is thus formed by a whole number from 0 to 7.
For each quantified signal, one then determines (block 58) a shade code corresponding to the whole number obtained. Eight codes are predetermined so as to actuate, after storage in the memory 43, the recording of a grade from among a range running from white to black. Each code is made up of a regular succession of binary digits in which the proportion of ones is a function of the shade of grey desired. The black code is a succession of ones in order -to re-cord points forming a continuous line on the film-medium of the recorder. The white code is made up exclusively of zeros. Between these two extremes, six other codes are predetermined by the repetitive successions of zeros and ones, with a decreasing proportion of ones, so as to obtain six shades of grey ranging from black to white. In one embodiment, the six predetermined codes have propor-tions of ones equal to 1/3, 1/4, l/6, 1/8, 1/12 and 1/16 in relation to the total number of digits.
The code selected for each quantified signal is entered into a pre-determined section of the memory 43. Each memory section corresponds to a trans-verse zone on the film-medium. Eight memory sections are predetermined so as to match eight contiguous zones placed in the right-hand part of the recording. In the embodiment, each memory section includes 48 elements and corresponds to a transverse segment of about 6 m on the recording. The codes obtained for the signals successively examined are entered into successive sections of the memory 3, ~
43. The eight sections of the memory 43 are thus successively filled with zeros or ones. As seen earlier, the content of the memory, read in synchronism with the scanning of the recorder, controls the recording of a point along a trans-verse line of the film-medium with each occurrence of a 1 digi~. Each memory section thus controls the recording of a line of points of varying spacing de-pending on the quantified value of the corresponding measurement signal. The signals Q and Q4 are also applied to the plot circuit 42 to be recorded in the form of curves on a left-hand part of the film-medium. One then goes on to the ne~t signal of the present level ~block 61) and up to the last level (blocks 62 and 63).
Figure 5 shows a recording obtained on the film-medium 33. In the longitudinal direction of the medium, i.e. vertically in the figure, is located the depth scale with transverse lines or depth lines 65 and numbers such as 1550 entered on the left to indicate the depth of the borehole. The left-hand part of the recording is a classical representation of the average signals Q (dotted line) and the signals Q4 (solid line). These signals are represented by two curves 66 and 67 whose values at each level are indicated by the transverse posi-tion of the plot on the scale made up of longitudinal lines or scale lines 70.
The right-hand part of the recording is made up of eight contiguous bands Bl to B8 arranged parallel to each other on the medium. Each band is made up in the longitudinal direction of a succession of juxtaposed zones whose shades are determined, at the successive depth levels, as a function of the quantified signals Q . In the embodiment described up to the present, each band Bn corresponds to the signals Q coming from the given transducer Tn. Each zone is made up of a line of points whose density is controlled by the code entered in the memory 43, since each black point recorded on the film corresponds to a 1 digit of the memory. One thus obtains a representation of the periphery of the casing in the form of a developed area whose shade in each zone indicates the bonding quality of the cement. The dark parts correspond to good bonding of the cement on the casing (weak signal Qn) and the light parts to poor bonding (strong signal Q ). This recording shows clearly the presence of longitudinal communication channels in the cement, for example that indicated by the light zone 71.
In the embodiment described up to now, a band B of the recording cor-responds to a given transducer. In an improved embodiment, account is taken oE
any rotation of the downhole apparatus so as to match subs-tantially each band B
with a generatrix of the casing. To accomplish this, one places in the downhole appaTatus a rotation detector which can consist of an eccentric weight 73 (see Figure 1) mounted rotatably around the axis of the downhole apparatus 10, and a circular potentiometer whose wiper is driven by the eccentric weight 73 to furnish at each depth a signal repr0sentative of the direction of the transducer Tl in relation to the vertical plane going through the axis of the borehole. Al-though such an apparatus does not give a valid signal in a perfectly vertical borehole, it is sufficient in most cases for the desired direction detection.
Other types of more complex detectors can also be used, for example an accelero-meter or a gyroscopic detector. Each signal representative of the angular posi-tion of the transducer Tl is transmitted to the surface via the cable. Duringprocessing in the computer 27, this signal is used in the selection stage 56 for selecting as first signal the signal which comes from the transducer whose posi-tion is closest to the plane of -the eccentric weight, i.e. the lower generatrix of the borehole. From this ~irst examined signal, the processing of figure 4 is carried out by selecting successively the signals from the transducers placed at 45 degrees and then at 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees from the first. In this way, each recording band corres-~3~ j~3t~
ponds to the measurement signals relative to the generatrix of the casing even if the downhole apparatus turns in the borehole. On the film, the position of the band corresponding to the lower generatrix of the casing is predetermined either at the edge or in the middle of the developed area.
While the invention has been described in accordance with the pre-ferred embodiments as presently conceived, it is to be appreciated that the pre-ferred embodiments are illustrative and that the invention is not intended to be limited to the preferred embodiments. Modifications of the present invention not described herein will become apparent to those of ordinary skill in the art after a perusal of this disclosure. For example, the casing thickness deter-mination taught by the aforementioned Havira Paten-t may be displayed in accord-ance with the present invention. Such modifications, as well as other equival-ent methods and arrangements, are within the spirit and scope of the invention as expressed in the appended claims.
METHOD AND APPARATUS FOR OBIAINING A DISPLAY
OF A CIIARACTERISTIC OF THE PERIPHERY OF A BOREHOLE
BACKGROUND _ TIIE INVENTION
This invention relates to displays for the study of a characteristic associated with a borehole, and more particularly to a method and apparatus for producing a graphic recording of a characteristic of the periphery of a bore-hole, such as for example the quality of the cement bond around a casing.
Oil well completion operations Eor initial production begin with the placement of a casing and the injection of cement between the casing and the surrounding earth formations. The main function of the cement is to isolate the formations so as to avoid the flow of fluids along the casing between aquifer layers and other formations containing hydrocarbons. It is thus very important to know the bonding quality of the cement around the casing.
A logging apparatus for obtaining this information is described in U.S. Patent No. ~,255,798, issued March 10, 1981 to Havira. In one embodiment, the downhole apparatus comprises several (for example, eight) acoustic trans-ducers positioned helically around the body member for the inspection of the entire casing periphery. A signal is generated that is representative of the bonding quality of the cement on the part of the casing corresponding to the exploration field of this transducer.
One advantage of this apparatus is that it allows the study of the bonding of the cement on surfaces of limited size on the periphery of the cas-ing, thereby making it possible to identify communication channels between certain formations even when the average quality of the cement appears to be good. One of the difficulties encountered has to do with the recording of the results. In fact, if a conventional plot on a film medium is made of the output signal as a function of depth, a number of 35~
curves are obtained which are not directly utilizable and which are often even difficult to separate from each other. In addition, it is desirable to provide other data, for example the average quality of the cement, thus further compli-cating the representation.
Logging techniques for furnishing a continuous visual representation of the wall of the borehole or of the formation layers around it are described in Canadian Patent No. 685,727 ~Mann ~ Threadgold). Signals coming from current electrodes are used for the intensity modulation of an oscilloscope. The pur-pose is to obtain an image of the limits between the formation layers in order to deduce the dip; accordingly, the boundaries between the changes in the record-ing shade give the desired information of the layer limits. The shades them-selves, which correspond to resistivity values, are strictly speaking of no interest. In addition, a spot whose intensity is modulated in proportion to the amplitude of the signal does not give a satisfac-tory distribution of shades for the objects of this invention.
SUMMARY OF THE INVENTION
-The object of this invention therefore is to provide a graphic display or recording of the bonding quality of the cement around a casing, in which the periphery of the casing is represented in the form of a developed area whose shade in each zone indicates this bonding quality in a satisEactory manner.
Another object of the invention is to provide a method and an appa-ratus for obtaining such a display or recording.
The aforementioned and other objects are achieved by the present inven-tion in accordance with a method for producing a graphic display, such as for example a film record, of a characteristic of the periphery of a longitudinal cavity passing through earth formations, such as for example the bonding quality of the cement in a cased borehole. A plurality of measurement signals respec-i3~
tively representative of the characteristic for portions of the periphery distri-buted around the cavity are produced. These measurement signals are converted into respective quantified signals having a limited number of possible values.
A shading code is selected for each such measurement signal based on the quanti-fied value thereof. For each depth level, a line modulated by the selected shad-ing codes is displayed, producing over a plurality of depth levels parallel longitudinal bands. Each band comprises a succession of shaded zones.
A variation of this method includes the additional steps of producing a signal representative of the position associated with a predetermined one of the measurement signals, and selecting longitudinal positions for displaying the shaded zones of the parallel bands.
The aforementioned and other objects are achieved by the present inven-tion in accordance with an apparatus for producing a graphic display, such as for example a film record, of a characteristic of the periphery of a longitudi-nal cavity passing through earth formations, such as for example the bonding quality of the cement in a cased borehole. Measuring means, including a plural-ity of transducers, is provided for producing, at different depth levels, a plurality of measurement signals respectively representative of said character-istic for portions of the periphery distributed around the cavity. Processing means, comprising memory means and shading code selecting means, is provided for converting said measurement signals into respective qualified signals having a limited number of possible values. Means is provided for displaying a line modu-lated by the selected shading codes, producing over a plurality of depth levels parallel longitudinal bands. Each band comprises a succession of shaded zones.
A variation of this apparatus further comprises means for producing a signal representative of the position of at least a predetermined one of the transducers, and means responsive to this position signal for selecting longitu-~, 53'j~
dinal positions for displaying the shades zones of the bands at each respectivedepth level.
Other objects, featu-res, and characteristics of the present invention will become apparent upon consideration of the following Detailed Description and the appended Claims, with reference to the accompanying Drawings, all of which are part of this Specification.
BRIEF DESCRIPTION OF Tt-lE DRAWINGS
In the drawings, where like reference characters indicate like ele-ments, Figure 1 is a partly block, partly pictoral schematic diagram of an apparatus in accordance with the present invention, shown inserted in a cased cemented borehole;
Figure 2 is a block schematic diagram of the optical recorder of Figure l;
Figure 3 is a flowchart representing a sequence of stages in accord-ance with the present invention, for execution by the apparatus of Figure 1, and more particularly by the computer shown in Figure l;
Figure 4 is a flowchart representing a process stage of Figure 3 in greater detail; and Figure 5 is an illustration of a display on a recording medium, ob-tained in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figure 1, an acoustic logging apparatus for studying the quality of the cement comprises a downhole apparatus lO suspended in a borehole 11 at the end of a mul*i-conductor çable 12. The borehole 11 which goes through formations 13 is equipped with a casing 14 surrounded by cement 15 injected be-tween this casing and the formations 13. This logging apparatus is described in _~_ greater detail in the above-mentioned U.S. Patent to Havira. In general, how-ever, the downhole apparatus 10 includes an elongated body member 16 maintained in the axis of the casing by upper 17 and ]ower 18 centering devices. On the body member are fixed eight acoustic transducers 20, Tl to T8, arranged heli-cally so as to inspect portions of casing distributed regularly on the periphery of the borehole. In the embodiment of the figure, the position of a transducer is deduced from the position of the preceding one by a ~5 rotation around the axis of the body member. Other arrangements are obviously possible with differ-ent numbers of transducers and/or different arrangements of these transducers around the borehole. Each transducer 20 (Tn) is controlled for the transmission, in a radial direction, of acoustic pulses of short duration whose spectrum has an average frequency of about 500 kHz. Each transmitted pulse is reflected by the different interfaces it encounters to yield an echo signal detected by the same transducer T which then operates as a receiver. This detected signal in-cludes aninitial segment coming from an initial reflection on the casing and a second segment corresponding to a reverberation within the casing.
Inside the body member are placed electronic circuits connected to the output o:E the transducers to generate raw signals in response to the detected echo signals. The first raw signals Wl for each transducer T are representa-tive of the maximum amplitude reached by the initial segment of each detectedsignal. Second raw signals W2n are obtained by rectifying and integrating the second segment, characterized as the reverberation segment, of each signal de-tected by each transducer T . Other raw signals can also be produced, for example the transi-t times ~t of the segments reflected on each transducer.
These raw signals for the eight transducers are converted into digital form and sent to the surface via transmission circuits connected to the conductors of the cable 12. Circuits for producing these raw signals are described in greater de-tail in the above-mentioned Havira Patent.
~ r-93t~
The conduc-tors of the cable 12 are connected on the surface to acquisi-tion circuit 22 which processes the transmission signals coming from the down-hole apparatus 10 and enters the raw signals Wl , W2 , ~t in a memory 23. The memory 23 is updated whenever signals are received, for example every 125 milli-seconds. A cable movement detection device, including a wheel 25 bearing tangen-tially on the cable, controls a depth pulse generator 26 which delivers a pulse whenever the cable is moved by a predetermined unit length. One thus obtains signals representative of the depth of the downhole apparatus 10.
The depth signals coming from the generator 26 are used by a computer 27 to perform a series of processing stages at each depth level. As an example, this series of stages can be carried out whenever the downhole apparatus is moved 5 cm. In other words, the interval between the depth levels examined suc-cessively is 5 cm.
The processing of the computer 27 furnishes a first set of output signals to a magnetic recorder 30 which records them in digital form, level by level, on magnetic tape. This magnetic recording makes it possible to use auto-matic data processing if desired. The computer 27 also furnishes, for each level, a second set of output signals to an optical recorder 31 which provides, on a film, a graphic recording particularly satisfactory for fast visual inter-pretation. In the example, the recorder is of the cathode-ray-tube type con-trolled by electronic circuits as described in U.S. Patent Numbers 3,986,163 and 4,010,476, issued to Elliott on October 12, 1976 and March 1, 1977 respectively.
Referring to Figure 2, which represents optical recorder 31 schematic-ally, a medium 33 consisting of a photographic film is moved in front of a cathode-ray-tube 34 to be exposed by the spot of this tube. The transverse posi-tion of the spot on the film is controlled by a scanning circuit 35 and its luminosity is controlled by an intensity circuit 36. The intensity control cir-3~
cuit 36 is synchronized with the scanning circuit to release the electron beamof the twbe in order to place points at predetermined transverse locations on the medium.
The obtained recording includes a classical part having a grid made up of transverse depth lines and longitudinal scale lines and curves which repre-sent on this grid the variations, indicated transversely, of certain output signals as a function of depth. This classical part is obtained by adding, in a combination circuit 37, signals coming from depth line circuit 40, scale line circuit 41, and plot circuit 42. These circuits are described in greater detail in the above-mentioned Elliott Patents.
The recorder 31 also includes a memory 43 containing a succession of binary digits capable of being read under the action of a control circuit 44.
The succession of binary digits is applied to the combination circuit 37 in syn-chronism with the transverse scanning of the film. The memory 43 is read from one end to the other during a transverse scan of the medium and the reading of each binary digit of value 1 actuates the entering of a black point on the film.
The memory 43 includes a number of binary digits chosen so as to be able to enter a point every 0.13 mm transversely on the film. A succession of "1"
digits corresponds to a continuous transverse black line. This memory 43 is particularly well suited to the recording of shades according to the invention as explained further below.
Referring to Figure 3, the processing stages carried out in the com-puter 27 are done level by level, i.e., in the example, every 5 cm (2") in res-ponse to the depth signals co~ing from the generator 26. The first stage con-sists in the depthwise correlation of the raw measurement signals (block 47).
To accomplish this, the raw measurement signals coming from each transducer T
of the downhole apparatus are stored in memory to be read after a period corres-~ ~5~35~3 ponding to the upward movement time of the lowest transducer Tl, up to the levelof the transducer examined T . This period thus depends on the speed of the downhole apparatus furnished by the depth pulse generator 26. The depthwise correlated raw measurements are then combined to obtain eight series of signals Ql to Q8 representative of -the bonding quality of the cement on portions of cas-ing distributed regularly around the borehole. For each transducer T a signal ~ ls calculated at each level ~block 48) in accordance with the ratio W2n/Wl of the raw signals coming from this transducer. As described in the above-mentioned Havira Patent, this ratio furnishes a signal representative of the bonding quality of the cement on the casing portion explored by the transducer Tn .
One also calculates (block 49) the average Q of the signals Q at each level and, if necessary, the fourth power Q4 of this average. The average Q
indicates the average bonding quality of the cement around the casing. The signal Q4 is of interest because it is close to the results obtained by appa-ratus used formerly for cement detection and allows a comparison with them.
The raw and calculated measurement signals are transmitted (block 50) to the magnetic recorder to be recorded in digital form level by level on mag-netic tape. The calculated signals moreover are processed ~block 51) to furnish an optical recording. The stages 47 to 51 are carried out level by level, i.e.
every S cm in depth (block 53) up to the last levels to be processed (block 52).
The processing stage 51 is represented in greater detail in Figure 4.
After a first initialization stage ~block 55), the first signal Q to be studied is selected ~block 56). In , first embodiment, one selects as the first signal studied the signal Ql coming from the first transducer Tl.
The signals studied Qn are selected in the order Ql to Q8 in order to match each recording band with the signals coming from a transducer. In the .i .:~
Q-~t~
following stage, the studied measurement signal Qn is converted into a quanti-fied signal having eight possible values made up of whole numbers from 0 to 7 (block 57). This stage includes a first scale changing operation for normaliz-ing the signal Q and bringing its variation range between zero and one, if such is not already the case. A second operation consists in multiplying by eight the normalized signal and in keeping only the whole part which is thus formed by a whole number from 0 to 7.
For each quantified signal, one then determines (block 58) a shade code corresponding to the whole number obtained. Eight codes are predetermined so as to actuate, after storage in the memory 43, the recording of a grade from among a range running from white to black. Each code is made up of a regular succession of binary digits in which the proportion of ones is a function of the shade of grey desired. The black code is a succession of ones in order -to re-cord points forming a continuous line on the film-medium of the recorder. The white code is made up exclusively of zeros. Between these two extremes, six other codes are predetermined by the repetitive successions of zeros and ones, with a decreasing proportion of ones, so as to obtain six shades of grey ranging from black to white. In one embodiment, the six predetermined codes have propor-tions of ones equal to 1/3, 1/4, l/6, 1/8, 1/12 and 1/16 in relation to the total number of digits.
The code selected for each quantified signal is entered into a pre-determined section of the memory 43. Each memory section corresponds to a trans-verse zone on the film-medium. Eight memory sections are predetermined so as to match eight contiguous zones placed in the right-hand part of the recording. In the embodiment, each memory section includes 48 elements and corresponds to a transverse segment of about 6 m on the recording. The codes obtained for the signals successively examined are entered into successive sections of the memory 3, ~
43. The eight sections of the memory 43 are thus successively filled with zeros or ones. As seen earlier, the content of the memory, read in synchronism with the scanning of the recorder, controls the recording of a point along a trans-verse line of the film-medium with each occurrence of a 1 digi~. Each memory section thus controls the recording of a line of points of varying spacing de-pending on the quantified value of the corresponding measurement signal. The signals Q and Q4 are also applied to the plot circuit 42 to be recorded in the form of curves on a left-hand part of the film-medium. One then goes on to the ne~t signal of the present level ~block 61) and up to the last level (blocks 62 and 63).
Figure 5 shows a recording obtained on the film-medium 33. In the longitudinal direction of the medium, i.e. vertically in the figure, is located the depth scale with transverse lines or depth lines 65 and numbers such as 1550 entered on the left to indicate the depth of the borehole. The left-hand part of the recording is a classical representation of the average signals Q (dotted line) and the signals Q4 (solid line). These signals are represented by two curves 66 and 67 whose values at each level are indicated by the transverse posi-tion of the plot on the scale made up of longitudinal lines or scale lines 70.
The right-hand part of the recording is made up of eight contiguous bands Bl to B8 arranged parallel to each other on the medium. Each band is made up in the longitudinal direction of a succession of juxtaposed zones whose shades are determined, at the successive depth levels, as a function of the quantified signals Q . In the embodiment described up to the present, each band Bn corresponds to the signals Q coming from the given transducer Tn. Each zone is made up of a line of points whose density is controlled by the code entered in the memory 43, since each black point recorded on the film corresponds to a 1 digit of the memory. One thus obtains a representation of the periphery of the casing in the form of a developed area whose shade in each zone indicates the bonding quality of the cement. The dark parts correspond to good bonding of the cement on the casing (weak signal Qn) and the light parts to poor bonding (strong signal Q ). This recording shows clearly the presence of longitudinal communication channels in the cement, for example that indicated by the light zone 71.
In the embodiment described up to now, a band B of the recording cor-responds to a given transducer. In an improved embodiment, account is taken oE
any rotation of the downhole apparatus so as to match subs-tantially each band B
with a generatrix of the casing. To accomplish this, one places in the downhole appaTatus a rotation detector which can consist of an eccentric weight 73 (see Figure 1) mounted rotatably around the axis of the downhole apparatus 10, and a circular potentiometer whose wiper is driven by the eccentric weight 73 to furnish at each depth a signal repr0sentative of the direction of the transducer Tl in relation to the vertical plane going through the axis of the borehole. Al-though such an apparatus does not give a valid signal in a perfectly vertical borehole, it is sufficient in most cases for the desired direction detection.
Other types of more complex detectors can also be used, for example an accelero-meter or a gyroscopic detector. Each signal representative of the angular posi-tion of the transducer Tl is transmitted to the surface via the cable. Duringprocessing in the computer 27, this signal is used in the selection stage 56 for selecting as first signal the signal which comes from the transducer whose posi-tion is closest to the plane of -the eccentric weight, i.e. the lower generatrix of the borehole. From this ~irst examined signal, the processing of figure 4 is carried out by selecting successively the signals from the transducers placed at 45 degrees and then at 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees from the first. In this way, each recording band corres-~3~ j~3t~
ponds to the measurement signals relative to the generatrix of the casing even if the downhole apparatus turns in the borehole. On the film, the position of the band corresponding to the lower generatrix of the casing is predetermined either at the edge or in the middle of the developed area.
While the invention has been described in accordance with the pre-ferred embodiments as presently conceived, it is to be appreciated that the pre-ferred embodiments are illustrative and that the invention is not intended to be limited to the preferred embodiments. Modifications of the present invention not described herein will become apparent to those of ordinary skill in the art after a perusal of this disclosure. For example, the casing thickness deter-mination taught by the aforementioned Havira Paten-t may be displayed in accord-ance with the present invention. Such modifications, as well as other equival-ent methods and arrangements, are within the spirit and scope of the invention as expressed in the appended claims.
Claims (20)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for producing a graphic display of a characteristic of the periphery of a longitudinal cavity passing through earth formations, comprising the steps of:
producing, at a plurality of depth levels, a plurality of measurement signals respectively representative of said characteristic for portions of the periphery which are distributed around the cavity;
converting, for each depth level, said measurement signals into respective quantified signals having a limited number of possible values;
selecting, for each depth level and from among a limited number of predeter-mined shading codes which correspond to the limited number of possible values of quantified signals, a shading code for each of said quantified signals according to the quantified value thereof; and displaying, for the plurality of depth levels, at least one line for each depth level, said line being modulated by said selected shading codes, for producing parallel longitudinal bands respectively comprising a suc-cession of shaded zones, whereby the periphery of the cavity is repre-sented in the form of a developed area whose shading in each zone indi-cates the value of the characteristic at the corresponding depth level and location on the periphery.
producing, at a plurality of depth levels, a plurality of measurement signals respectively representative of said characteristic for portions of the periphery which are distributed around the cavity;
converting, for each depth level, said measurement signals into respective quantified signals having a limited number of possible values;
selecting, for each depth level and from among a limited number of predeter-mined shading codes which correspond to the limited number of possible values of quantified signals, a shading code for each of said quantified signals according to the quantified value thereof; and displaying, for the plurality of depth levels, at least one line for each depth level, said line being modulated by said selected shading codes, for producing parallel longitudinal bands respectively comprising a suc-cession of shaded zones, whereby the periphery of the cavity is repre-sented in the form of a developed area whose shading in each zone indi-cates the value of the characteristic at the corresponding depth level and location on the periphery.
2. A method as in claim 1, wherein each of said shading codes comprises a succession of binary digits for recording a transverse line of points, said suc-cession of binary digits having different proportions of binary ones and zeros for producing different densities of points.
3. A method as in claim 1 or 2 further comprising the steps of:
producing an average signal by averaging said measurement signals at each depth level; and displaying a curve representative of the value of said average signal to indicate the average value of said characteristic at each depth level.
producing an average signal by averaging said measurement signals at each depth level; and displaying a curve representative of the value of said average signal to indicate the average value of said characteristic at each depth level.
4. A method as in claim 1 further comprising the steps of:
producing, for each depth level, a signal representative of the position associated with a predetermined one of the measurement signals; and selecting, for each depth level in response to said position signal, long-itudinal bands for displaying portions of said modulated line, whereby the longitudinal bands of said developed area are related respectively to longitudinal strips of the periphery.
producing, for each depth level, a signal representative of the position associated with a predetermined one of the measurement signals; and selecting, for each depth level in response to said position signal, long-itudinal bands for displaying portions of said modulated line, whereby the longitudinal bands of said developed area are related respectively to longitudinal strips of the periphery.
5. A method as in claim 4, wherein the step of producing a position signal comprises detecting, at each depth level, the angle between the direction of a portion of the periphery related to said predetermined measurement signal and a predetermined vertical plane going through the axis of the cavity.
6. A method as in claim 1 or 2 wherein said periphery comprises a casing surrounded by cement, and wherein said step of producing measurement signals com-prises the step of producing, at a plurality of depth levels, a plurality of measurement signals respectfully respresentative of bonding quality of said cement for portions of said casing, whereby a display is produced which repre-sents the periphery of the cavity in the form of a developed area whose shading in each zone indicates the bonding quality of said cement to respective portions of said casing.
7. A method as in claim 4 wherein said periphery comprises a casing surrounded by cement, and wherein said step of producing measurement signals comprises the step of producing, at a plurality of depth levels, a plurality of measurement signals respectfully representative of bonding quality of said cement for portions of said casing, whereby a display is produced which rep-resents the periphery of the cavity in the form of a developed area whose shading in each zone indicates the bonding quality of said cement to respect-ive portions of said casing.
8. A method as in claim 5 wherein said periphery comprises a casing surrounded by cement, and wherein said step of producing measurement signals comprises the step of producing, at a plurality of depth levels, a plurality of measurement signals respectfully representative of bonding quality of said cement for portions of said casing, whereby a display is produced which represents the periphery of the cavity on the form of a developed area whose shading in each zone indicates the bonding quality of said cement to respect-ive portions of said casing.
9. A method for producing a graphic display of a characteristic of the periphery of a longitudinal cavity passing through earth formations, comprising the steps of:
obtaining for each depth level over a plurality of depth levels of said cavity, a plurality of measurement signals representative of said character-istic over respective portions of the periphery;
respectively converting each of said measurement signals into a quantified signal having a finite number of possible values;
respectively selecting, in accordance with the value of each of said quantified signals, a shading code from a predetermined number of predeter-mined shading codes;
producing an optical display of zones, each zone thereof corresponding to a respective depth level and portion of the periphery and being distinguished in accordance with respective selected shading code.
obtaining for each depth level over a plurality of depth levels of said cavity, a plurality of measurement signals representative of said character-istic over respective portions of the periphery;
respectively converting each of said measurement signals into a quantified signal having a finite number of possible values;
respectively selecting, in accordance with the value of each of said quantified signals, a shading code from a predetermined number of predeter-mined shading codes;
producing an optical display of zones, each zone thereof corresponding to a respective depth level and portion of the periphery and being distinguished in accordance with respective selected shading code.
10. A method as in claim 9, wherein each of said predetermined shading codes comprises a succession of binary ones and zeros at different proportions for obtaining a range of shading to distinguish said zones, and wherein said optical display producing step comprises the step of respectively controlling the recording of a point along a transverse line of a medium with each occur-rance of a binary one in each of said respectively selected shading code, whereby zones at respective depth levels having respective shadings represent-ative of said characteristic are created on said medium.
11. A method as in claim 10 further comprising the step of detecting a position signal, and wherein said optical display producing step further comprises the step of aligning the zones at respective depth levels relative to a generatrix of the periphery.
12. A method as in claim 9 further comprising the steps of detecting a position signal, and wherein said optical display producing step comprises the step of aligning the zones at respective depth levels relative to a gen-eratrix of the periphery.
13. An apparatus for producing a graphic display of a characteristic of the periphery of a longitudinal cavity passing through earth formations, comprising:
measuring means, including a plurality of transducers, for producing, at a plurality of depth levels, a plurality of measurement signals respectively representative of said characteristic for portions of the periphery which are distributed around the cavity;
processing means for converting, for each depth level, said measurement signals into respective quantified signals having a limited number of possible values, said processing means comprising:
memory means for storing a limited number of predetermined shading codes which correspond to the limited number of possible values of the quantified signals; and means for selecting, for each depth level, a shading code for each of said quantified signals according to the quantified value thereof; and means for displaying, for the plurality of depth levels, at least one line for each depth level, said line being modulated by said selected shading codes, for producing parallel longitudinal bands respectively comprising a succession of shaded zones, whereby the periphery of the cavity is represented in the form of a developed area whose shading in each zone indicates the value of the characteristic at the corresponding depth level and location on the periphery.
measuring means, including a plurality of transducers, for producing, at a plurality of depth levels, a plurality of measurement signals respectively representative of said characteristic for portions of the periphery which are distributed around the cavity;
processing means for converting, for each depth level, said measurement signals into respective quantified signals having a limited number of possible values, said processing means comprising:
memory means for storing a limited number of predetermined shading codes which correspond to the limited number of possible values of the quantified signals; and means for selecting, for each depth level, a shading code for each of said quantified signals according to the quantified value thereof; and means for displaying, for the plurality of depth levels, at least one line for each depth level, said line being modulated by said selected shading codes, for producing parallel longitudinal bands respectively comprising a succession of shaded zones, whereby the periphery of the cavity is represented in the form of a developed area whose shading in each zone indicates the value of the characteristic at the corresponding depth level and location on the periphery.
14. An apparatus as in claim 13, wherein said memory means comprises means for storing a predetermined successions of binary digits to control the recording of a transverse line of points, each of said successions of binary digits having different proportions of binary ones and zeros for producing different densities of points.
15. An apparatus as in claim 13 or 14, wherein said processing means further comprises:
means for producing an average signal by averaging said measurement signals at each depth level;
said apparatus further comprising:
means for displaying a curve representative of the value of said aver-age signal to indicate the average value of said characteristic at each depth level.
means for producing an average signal by averaging said measurement signals at each depth level;
said apparatus further comprising:
means for displaying a curve representative of the value of said aver-age signal to indicate the average value of said characteristic at each depth level.
16. An apparatus as in claim 14 further comprising:
means for producing, for each depth level, a signal representative of the position of at least a predetermined one of said transducers; and means responsive to said position signal for selecting, for each depth level, longitudinal bands for displaying portions of said modulated line, whereby the longitudinal bands of said developed area are related respectively to longitudinal strips of the periphery.
means for producing, for each depth level, a signal representative of the position of at least a predetermined one of said transducers; and means responsive to said position signal for selecting, for each depth level, longitudinal bands for displaying portions of said modulated line, whereby the longitudinal bands of said developed area are related respectively to longitudinal strips of the periphery.
17. An apparatus as in claim 16, wherein said means for producing a position signal comprises a detector sensitive to the acceleration of gravity to furnish a signal representative of the angle between the direction of one of said transducers and a predetermined vertical plane going through the axis of the cavity.
18. An apparatus as in claim 13 or 14, wherein said periphery comprises a casing surrounded by cement, and wherein said measuring means comprise means for producing, at a plurality of depth levels, a plurality of measure-ment signals respectively representative of bonding quality of said cement for portions of said casing, whereby a display is produced by said displaying means which represents the periphery of the cavity in the form of a developed area whose shading in each zone indicates the bonding quality of said cement to respective portions of said casing.
19. An apparatus as in claim 16, wherein said periphery comprises a casing surrounded by cement, and wherein said measuring means comprise means for producing, at a plurality of depth levels, a plurality of measurement signals respectively representative of bonding quality of said cement for portions of said casing, whereby a display is produced by said displaying means which represents the periphery of the cavity in the form of a devel-oped area whose shading in each zone indicates the bonding quality of said cement to respective portions of said casing.
20. An apparatus as in claim 17, wherein said periphery comprises a casing surrounded by cement, and wherein said measuring means comprise means for producing, at a plurality of depth levels, a plurality of measurement signals respectively representative of bonding quality of said cement for portions of said casing, whereby a display is produced by said displaying means which represents the periphery of the cavity in the form of a developed area whose shading in each zone indicates the bonding quality of said cement to respective portions of said casing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8020890A FR2491123A1 (en) | 1980-09-30 | 1980-09-30 | METHOD AND DEVICE FOR OBTAINING RECORDING OF CEMETERY QUALITY IN A SURVEY |
| FR80.20890 | 1980-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1185350A true CA1185350A (en) | 1985-04-09 |
Family
ID=9246399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386848A Expired CA1185350A (en) | 1980-09-30 | 1981-09-29 | Method and apparatus for obtaining a display of a characteristic of the periphery of a borehole |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0055634B1 (en) |
| AU (1) | AU549142B2 (en) |
| BR (1) | BR8106218A (en) |
| CA (1) | CA1185350A (en) |
| DE (1) | DE3170857D1 (en) |
| FR (1) | FR2491123A1 (en) |
| MX (1) | MX150346A (en) |
| NO (1) | NO156768C (en) |
| OA (1) | OA06911A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4805156A (en) * | 1986-09-22 | 1989-02-14 | Western Atlas International, Inc. | System for acoustically determining the quality of the cement bond in a cased borehole |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2532059A1 (en) * | 1982-08-19 | 1984-02-24 | Schlumberger Prospection | METHOD AND DEVICE FOR VISUAL PRESENTATION, IN PARTICULAR GRAPHIC RECORDING OF MEASUREMENT RESULTS IN A WELL |
| IN158732B (en) * | 1982-10-27 | 1987-01-10 | Schlumberger Ltd | |
| FR2569476B1 (en) * | 1984-08-24 | 1987-01-09 | Schlumberger Prospection | METHOD AND DEVICE FOR EVALUATING THE QUALITY OF THE CEMENT SURROUNDING THE CASING OF A WELL |
| FR2569859B1 (en) * | 1984-09-05 | 1986-08-29 | Schlumberger Prospection | LOGGING METHOD AND DEVICE FOR THE ACOUSTIC INSPECTION OF A BORING WITH A TUBING |
| NO870879L (en) * | 1986-03-13 | 1987-09-14 | Schlumberger Ltd | PROCEDURE AND APPARATUS FOR BORING HOLE. |
| FR2646513B1 (en) * | 1989-04-26 | 1991-09-20 | Schlumberger Prospection | LOGGING METHOD AND DEVICE FOR THE ACOUSTIC INSPECTION OF A BORING WITH A TUBING |
| EP2749908A1 (en) * | 2012-12-28 | 2014-07-02 | Services Pétroliers Schlumberger | Enhanced Visualization of Logging Information in Cased Wells Using Dynamic Normalization |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3321770A (en) * | 1964-12-04 | 1967-05-23 | Texas Instruments Inc | Apparatus for variable density recording |
| US3680042A (en) * | 1969-05-26 | 1972-07-25 | Schlumberger Technology Corp | Methods and apparatus for recording well logging data |
| US3952282A (en) * | 1974-07-17 | 1976-04-20 | Mobil Oil Corporation | Two-receiver, variable-density logging system |
-
1980
- 1980-09-30 FR FR8020890A patent/FR2491123A1/en active Granted
-
1981
- 1981-09-22 DE DE8181401465T patent/DE3170857D1/en not_active Expired
- 1981-09-22 EP EP81401465A patent/EP0055634B1/en not_active Expired
- 1981-09-23 AU AU75619/81A patent/AU549142B2/en not_active Ceased
- 1981-09-28 BR BR8106218A patent/BR8106218A/en unknown
- 1981-09-29 MX MX189397A patent/MX150346A/en unknown
- 1981-09-29 NO NO813301A patent/NO156768C/en unknown
- 1981-09-29 CA CA000386848A patent/CA1185350A/en not_active Expired
- 1981-09-29 OA OA57506A patent/OA06911A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4805156A (en) * | 1986-09-22 | 1989-02-14 | Western Atlas International, Inc. | System for acoustically determining the quality of the cement bond in a cased borehole |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2491123A1 (en) | 1982-04-02 |
| AU7561981A (en) | 1982-04-08 |
| EP0055634A1 (en) | 1982-07-07 |
| NO813301L (en) | 1982-03-31 |
| OA06911A (en) | 1983-05-31 |
| AU549142B2 (en) | 1986-01-16 |
| DE3170857D1 (en) | 1985-07-11 |
| FR2491123B1 (en) | 1984-02-17 |
| BR8106218A (en) | 1982-06-15 |
| MX150346A (en) | 1984-04-18 |
| NO156768B (en) | 1987-08-10 |
| EP0055634B1 (en) | 1985-06-05 |
| NO156768C (en) | 1987-11-25 |
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