CA2011437C - Logging method and apparatus using a rotating sensor - Google Patents
Logging method and apparatus using a rotating sensor Download PDFInfo
- Publication number
- CA2011437C CA2011437C CA002011437A CA2011437A CA2011437C CA 2011437 C CA2011437 C CA 2011437C CA 002011437 A CA002011437 A CA 002011437A CA 2011437 A CA2011437 A CA 2011437A CA 2011437 C CA2011437 C CA 2011437C
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- Prior art keywords
- sensor
- target
- axis
- borehole
- support
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V13/00—Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00
-
- 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
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/30—Arrangements for calibrating or comparing, e.g. with standard objects
-
- 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
- G01V1/46—Data acquisition
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/26—Scanned objects
- G01N2291/263—Surfaces
- G01N2291/2636—Surfaces cylindrical from inside
Abstract
Logging equipment for use in a borehole has a sensor such as an ultrasonic sensor, oriented radially towards the wall of the borehole and rotatable in one direction during measurement about the longitudinal axis (XX) of the equipment. In order to allow the sensor to be recalibrated downhole, the equipment also includes a target which is automatically brought face to face with the sensor upon reversal of the direction of rotation of the sensor. The sensor can thus be calibrated under conditions which are as close as possible to the conditions of measurement.
Description
~~1~4~~
LOGGING METHOD AND APPARATUS USING A ROTATING SENSOR
DESCRIPTION
The invention relates to a logging method using a rotating sensor such as a sonic or ultrasonic sensor to scan the wall of the borehole circumferentially. The invention also relates to apparatus for implementing the method.
In order to perform measurements e.g. in order to evaluate the quality of the cement bond with the casing of the well, various types of measurement apparatus have been developed.
A first prior solution, described in U.S. Patent 4,524,433, consists in using an apparatus having at least one measurement sensor which points radially relative to the longitudinal axis of the apparatus and which is driven to rotate about said axis in order to scan the wall of the borehole circumferentially at the level of the sensor. By combining this rotary motion of the sensor with a regular translation motion of the apparatus along the borehole, the wall of the borehole is scanned along a helical trajectory enabling the entire wall to be inspected.
In measurement apparatus designed in this manner, there is no way of recalibrating the measurement sensor in situ while it scans the borehole. The operating conditions of the apparatus, such as temperature and pressure, which are extremely severe, vary along the borehole, which frequently results in changes in the measurements performed. In the absence of recalibration, this can lead to errors that may sometimes be significant.
U.S. Patent 4,685,092 describes a measurement apparatus of a different design in which a plurality of fixed measurement sensors are directed radially towards the wall of the borehole. These measurement sensors are placed on the apparatus along a helix such 2 _ 20 1 1 4 3 7 that displacing the apparatus parallel to its own axis inside the borehole has the effect of scanning the major portion of the wall of the borehole.
Compared with the above-described apparatus, this apparatus does not provide a complete azimuth coverage of the wall of the borehole. But it includes calibration means comprising a calibration sensor which is distinct from the measurement sensors and which points downwards, along the longitudinal axis of the apparatus, towards a calibrating target facing this sensor.
By providing substantially the same distance between the target and the calibration sensor as occurs between the measurement sensors and the wall of the borehole, the sensor can be recalibrated from time to time while the borehole is being scanned.
However, this solution is only partially satisfactory, in particular due to the fact that the calibration sensor is distinct from the measurement sensors. As a result, the calibration does not take account of any dispersion phenomena that may exist between the measurement sensors. In addition, the calibration sensor points in a different direction than the measurement sensors so that the motion of the fluid contained in the borehole relative to the calibration sensor is not representative of the motion of the same fluid relative to the measurement sensors.
The object of the present invention is to provide a logging method and apparatus in which a target can be placed in front of a sensor pointing towards the wall of the borehole, in order to allow calibration of the sensor under conditions which are close to those which prevail during measurement.
According to the invention, this result is obtained by a logging method using a sensor fitted to equipment suitable for use in a borehole, comprising a measurement step in which the sensor is caused to rotate in a given direction in order to scan the wall of the borehole circumferentially, and a calibration step in which the sensor and a calibration target are brought face to face by reversing the direction of rotation of the sensor, whereby a reference measurement for calibrating the sensor can be obtained.
Preferably, the distance between the sensor and the target during the calibration step is substantially equal to the distance between the sensor and the wall of the borehole during the measurement step. In addition, with the rotation of the sensor being performed about an axis substantially parallel to the longitudinal direction of the borehole during the measurement step, the sensor and the target are brought face to face substantially perpendicularly to said longitudinal direction during the calibration step.
Advantageously, a target is used having limited angular lost motion relative to the sensor such that during a measurement step, the rotation of the sensor in said one direction is imparted to the target occupying a first angular position offset relative to the sensor, and when the direction of rotation of the sensor is reversed, this rotary motion is imparted to the target occupying a second angular position facing the sensor after said angular lost motion has been taken up.
The invention also provides logging apparatus suitable for use in a borehole, the apparatus comprising a housing, a sensor mounted on a rotary head rotatable about a longitudinal axis (XX) of the housing, and drive means for rotating the sensor about said axis in one direction to scan the wall of the borehole, the apparatus further comprising: a calibration target mounted on said rotary head; and displacement means responsive to the direction of rotation of the sensor in order to displace the sensor and the target relative to each other from a measurement position in which the sensor is oriented towards the wall of the borehole to a calibration position in which the sensor is face to face with the target, whenever the direction of rotation is reversed.
Advantageously, the displacement means comprise motion transmission means defining limited angular lost motion such that when the sensor is rotated in said one direction the A
- 3a -target occupies a measurement position which is angularly offset relative to the sensor and when the sensor is rotated in the opposite direction, the target occupies the calibration position.
Preferably, the apparatus includes a rotary head carrying a target support and rotatable about the longitudinal axis of the casing, and the sensor is rotatably supported by the target support about a first axis which is parallel to and offset from the longitudinal axis of the housing.
A
2~1143~
LOGGING METHOD AND APPARATUS USING A ROTATING SENSOR
DESCRIPTION
The invention relates to a logging method using a rotating sensor such as a sonic or ultrasonic sensor to scan the wall of the borehole circumferentially. The invention also relates to apparatus for implementing the method.
In order to perform measurements e.g. in order to evaluate the quality of the cement bond with the casing of the well, various types of measurement apparatus have been developed.
A first prior solution, described in U.S. Patent 4,524,433, consists in using an apparatus having at least one measurement sensor which points radially relative to the longitudinal axis of the apparatus and which is driven to rotate about said axis in order to scan the wall of the borehole circumferentially at the level of the sensor. By combining this rotary motion of the sensor with a regular translation motion of the apparatus along the borehole, the wall of the borehole is scanned along a helical trajectory enabling the entire wall to be inspected.
In measurement apparatus designed in this manner, there is no way of recalibrating the measurement sensor in situ while it scans the borehole. The operating conditions of the apparatus, such as temperature and pressure, which are extremely severe, vary along the borehole, which frequently results in changes in the measurements performed. In the absence of recalibration, this can lead to errors that may sometimes be significant.
U.S. Patent 4,685,092 describes a measurement apparatus of a different design in which a plurality of fixed measurement sensors are directed radially towards the wall of the borehole. These measurement sensors are placed on the apparatus along a helix such 2 _ 20 1 1 4 3 7 that displacing the apparatus parallel to its own axis inside the borehole has the effect of scanning the major portion of the wall of the borehole.
Compared with the above-described apparatus, this apparatus does not provide a complete azimuth coverage of the wall of the borehole. But it includes calibration means comprising a calibration sensor which is distinct from the measurement sensors and which points downwards, along the longitudinal axis of the apparatus, towards a calibrating target facing this sensor.
By providing substantially the same distance between the target and the calibration sensor as occurs between the measurement sensors and the wall of the borehole, the sensor can be recalibrated from time to time while the borehole is being scanned.
However, this solution is only partially satisfactory, in particular due to the fact that the calibration sensor is distinct from the measurement sensors. As a result, the calibration does not take account of any dispersion phenomena that may exist between the measurement sensors. In addition, the calibration sensor points in a different direction than the measurement sensors so that the motion of the fluid contained in the borehole relative to the calibration sensor is not representative of the motion of the same fluid relative to the measurement sensors.
The object of the present invention is to provide a logging method and apparatus in which a target can be placed in front of a sensor pointing towards the wall of the borehole, in order to allow calibration of the sensor under conditions which are close to those which prevail during measurement.
According to the invention, this result is obtained by a logging method using a sensor fitted to equipment suitable for use in a borehole, comprising a measurement step in which the sensor is caused to rotate in a given direction in order to scan the wall of the borehole circumferentially, and a calibration step in which the sensor and a calibration target are brought face to face by reversing the direction of rotation of the sensor, whereby a reference measurement for calibrating the sensor can be obtained.
Preferably, the distance between the sensor and the target during the calibration step is substantially equal to the distance between the sensor and the wall of the borehole during the measurement step. In addition, with the rotation of the sensor being performed about an axis substantially parallel to the longitudinal direction of the borehole during the measurement step, the sensor and the target are brought face to face substantially perpendicularly to said longitudinal direction during the calibration step.
Advantageously, a target is used having limited angular lost motion relative to the sensor such that during a measurement step, the rotation of the sensor in said one direction is imparted to the target occupying a first angular position offset relative to the sensor, and when the direction of rotation of the sensor is reversed, this rotary motion is imparted to the target occupying a second angular position facing the sensor after said angular lost motion has been taken up.
The invention also provides logging apparatus suitable for use in a borehole, the apparatus comprising a housing, a sensor mounted on a rotary head rotatable about a longitudinal axis (XX) of the housing, and drive means for rotating the sensor about said axis in one direction to scan the wall of the borehole, the apparatus further comprising: a calibration target mounted on said rotary head; and displacement means responsive to the direction of rotation of the sensor in order to displace the sensor and the target relative to each other from a measurement position in which the sensor is oriented towards the wall of the borehole to a calibration position in which the sensor is face to face with the target, whenever the direction of rotation is reversed.
Advantageously, the displacement means comprise motion transmission means defining limited angular lost motion such that when the sensor is rotated in said one direction the A
- 3a -target occupies a measurement position which is angularly offset relative to the sensor and when the sensor is rotated in the opposite direction, the target occupies the calibration position.
Preferably, the apparatus includes a rotary head carrying a target support and rotatable about the longitudinal axis of the casing, and the sensor is rotatably supported by the target support about a first axis which is parallel to and offset from the longitudinal axis of the housing.
A
2~1143~
In order to allow adaptation of the apparatus to the dimensions of the borehole, it is advantageous to provide an interchangeable target support on the rotary head.
In addition, the sensor is preferably removably fixed on a sensor support which is itself rotatable on the target support, whereby the same sensor can be used with different target supports.
In a first preferred embodiment of the invention, suitable for use with small-sized sensors, the target support is fixed on the rotary head and the motion transmission means defining said limited angular lost motion are placed between the sensor and the target support. The rotary drive means for the sensor then comprise a drive shaft mounted on said longitudinal axis inside the rotary head and a mechanism for transmitting the rotary motion of the shaft to the sensor.
In a second preferred embodiment of the invention suitable for use with sensors which are larger in size, the target support is supported by the rotary head about a second axis parallel to and offset from the first axis and the longitudinal axis of the casing, said second axis being situated between the first axis and the longitudinal axis when the sensor rotates in the measurement direction and the means for transmitting motion and defining the limited lost motion are placed between the rotary head and the target support.
In this case, the means for rotating the sensor comprise the rotary head and a mechanism for transmitting rotary motion from the head to the sensor.
Two preferred embodiments of the invention are described below by way of non-limiting example and with reference to the accompanying drawings, in which:
Figure 1 is a longitudinal section view showing the bottom end of measurement equipment located in a borehole and including apparatus in accordance with a first embodiment of the invention;
Figures 2A to 2D are section views on line II-II of Figure 1 showing various relative angular positions of the sensor and the target support in the equipment;
Figures 3A and 3B are diagrammatical longitudinal section views comparable to Figure 1, showing how the equipment can be adapted to boreholes of different diameters by virtue of the target support being interchangeable;
Figures 4A and 4B are longitudinal section views through measurement equipment including apparatus in accordance with a second embodiment of the invention, with the various parts of the apparatus being shown respectively in the positions they occupy during measurement and during calibration; and Figures 5A to 5C are diagrammatic section views on line V-V of Figure 4A respectively showing three relative positions of the sensor, the target support, and the rotary head of the equipment.
In Figure 1, overall reference 10 designates the bottom end of measurement equipment intended, for example, to inspect the cemen-ting of the casing 12 in a borehole which is nominally cylindrical, such as a borehole for hydrocarbon production.
The measurement equipment 10 includes a sensor 14 such as an ultrasonic sensor which is normally directed radially towards the wall of the well i.e. towards the casing 12, relative to the longitudinal axis XX of the equipment, thereby performing measurement at a distance.
Means described in greater detail below for rotating the sensor 14 about the longitudinal axis XX of the equipment enable the wall of the borehole to be scanned completely in azimuth when rotation is caused to take place clockwise as shown in Figure 2A. Simultaneous-ly, the entire equipment 10 is raised at a constant translation speed along its longitudinal axis by conventional means (not shown) situated above the ground. This causes the sensor to scan the wall of the borehole helically.
In order to ensure that the distance between the sensor 14 and the wall remains practically constant throughout this scanning mo-tion, the measurement equipment 10 is fitted in conventional manner with centering means constituted, for example, by extensible arms (not shown) brought into contact with the wall of the borehole. The longitudinal axis XX of the equipment then coincides substantially with the axis of the borehole.
According to the invention, in order to calibrate the sensor 14 inside the borehole, the measurement equipment 10 also includes a calibrating target 16 disposed parallel to the longitudinal XX of 2~1143~
In addition, the sensor is preferably removably fixed on a sensor support which is itself rotatable on the target support, whereby the same sensor can be used with different target supports.
In a first preferred embodiment of the invention, suitable for use with small-sized sensors, the target support is fixed on the rotary head and the motion transmission means defining said limited angular lost motion are placed between the sensor and the target support. The rotary drive means for the sensor then comprise a drive shaft mounted on said longitudinal axis inside the rotary head and a mechanism for transmitting the rotary motion of the shaft to the sensor.
In a second preferred embodiment of the invention suitable for use with sensors which are larger in size, the target support is supported by the rotary head about a second axis parallel to and offset from the first axis and the longitudinal axis of the casing, said second axis being situated between the first axis and the longitudinal axis when the sensor rotates in the measurement direction and the means for transmitting motion and defining the limited lost motion are placed between the rotary head and the target support.
In this case, the means for rotating the sensor comprise the rotary head and a mechanism for transmitting rotary motion from the head to the sensor.
Two preferred embodiments of the invention are described below by way of non-limiting example and with reference to the accompanying drawings, in which:
Figure 1 is a longitudinal section view showing the bottom end of measurement equipment located in a borehole and including apparatus in accordance with a first embodiment of the invention;
Figures 2A to 2D are section views on line II-II of Figure 1 showing various relative angular positions of the sensor and the target support in the equipment;
Figures 3A and 3B are diagrammatical longitudinal section views comparable to Figure 1, showing how the equipment can be adapted to boreholes of different diameters by virtue of the target support being interchangeable;
Figures 4A and 4B are longitudinal section views through measurement equipment including apparatus in accordance with a second embodiment of the invention, with the various parts of the apparatus being shown respectively in the positions they occupy during measurement and during calibration; and Figures 5A to 5C are diagrammatic section views on line V-V of Figure 4A respectively showing three relative positions of the sensor, the target support, and the rotary head of the equipment.
In Figure 1, overall reference 10 designates the bottom end of measurement equipment intended, for example, to inspect the cemen-ting of the casing 12 in a borehole which is nominally cylindrical, such as a borehole for hydrocarbon production.
The measurement equipment 10 includes a sensor 14 such as an ultrasonic sensor which is normally directed radially towards the wall of the well i.e. towards the casing 12, relative to the longitudinal axis XX of the equipment, thereby performing measurement at a distance.
Means described in greater detail below for rotating the sensor 14 about the longitudinal axis XX of the equipment enable the wall of the borehole to be scanned completely in azimuth when rotation is caused to take place clockwise as shown in Figure 2A. Simultaneous-ly, the entire equipment 10 is raised at a constant translation speed along its longitudinal axis by conventional means (not shown) situated above the ground. This causes the sensor to scan the wall of the borehole helically.
In order to ensure that the distance between the sensor 14 and the wall remains practically constant throughout this scanning mo-tion, the measurement equipment 10 is fitted in conventional manner with centering means constituted, for example, by extensible arms (not shown) brought into contact with the wall of the borehole. The longitudinal axis XX of the equipment then coincides substantially with the axis of the borehole.
According to the invention, in order to calibrate the sensor 14 inside the borehole, the measurement equipment 10 also includes a calibrating target 16 disposed parallel to the longitudinal XX of 2~1143~
the equipment and situated at the same level as the sensor 14. This target 16 and the sensor 14 are mounted on the equipment in such a manner that a reversal of the direction of rotation of the sensor about the longitudinal axis XX of the equipment brings the target 16 automatically in front of the sensor 14 under conditions which are as close as possible to the conditions under which real measurements are performed by the sensor.
To this end, the target 16 has characteristics which are as close as possible to those of the casing 12 under inspection. The distance between the sensor and the target in the calibration position is as close as possible to the distance between the sensor and the casing 12 during measurement. And the fluids present in the borehole also have relatively comparable flow characteristics in both positions.
In the embodiment shown in Figures 1 to 3, the sensor 14 is sufficiently small for the above-specified conditions to be obtained merely by rotating the sensor 14 about an axis YY parallel to, and offset from, the longitudinal axis XX of the equipment.
As shown in greater detail in Figure 1, this result is obtained in practice by means of measurement equipment 10 including a non-rotating tubular outer housing 18 in which a hollow outer shaft 20 is rotatably mounted by means of two bearings 22. This hollow outer shaft 20 constitutes a rotary head which extends downwards beyond the bottom end of the housing 18 in order to support a target support 24 on which the target 16 is fixed.
More precisely, the target support 24 is removably fixed on a tubular bottom portion 20a of the hollow shaft 20, e.g. by means of a ring 26 screwed on a threaded tubular top portion 24a of the support 24 so as to clamp a flange 20b fixed to the shaft 20 against the top edge of the threaded tubular portion 24a. A stud 28 mounted in the threaded top end 24a of the support 24 projects radially inwardly into a longitudinal groove 30 formed in the tubular bottom portion 20a of the shaft 20 so as to prevent relative rotation occurring between the shaft and the support 24.
Thus, the assembly constituted by the outer hollow shaft 20 and the target support 24 is free to rotate relative to the outer housing 18 of the equipment about the longitudinal axis XX thereof.
''~~~~4~'~
Regardless of the angular position of this assembly, the target 16 is fixed on the support 24 in such a manner as to be permanently disposed parallel to the longitudinal axis XX of the equipment and to be situated at a constant distance from said axis.
At a location diametrically opposite the target 16 about the longitudinal axis XX of the equipment, the target support 24 includes a block 24b adjacent to the threaded tubular portion 24a and in which a bore 32 is formed about an axis YY which is parallel to and offset from the longitudinal axis XX of the equipment. A
cylindrical rod 34 is mounted to rotate in said bore 32 and is restrained from translation by a screw 26 engaged in the block 24b and having an end received in a groove in the cylindrical rod 34.
The bottom end of the cylindrical rod 34 is fixed to a support plate 38 extending radially relative to the axis XX and YY and constituting the support for the sensor 14. The sensor 14 is removably fixed on said support plate 38 by fixing means such as screws (not shown).
It should be observed that the distance d between the sensor 14 and the inside wall of the borehole when the sensor is directed radially towards said borehole relative to the axis XX is approxima-tely equal to the distance between the same sensor and the target 16 when the sensor is rotated through 180° about the axis YY, as shown in dot-dashed lines in Figure 1.
While measurement is being performed, the sensor 14 must be permanently directed towards the wall of the borehole, and the distance d between said sensor and the wall should remain constant.
Rotary drive for the sensor must therefore be transmitted to the entire target support 24 so that the sensor does not rotate about the axis YY and so that the sensor rotates in unison with the support 24 about the axis XX of the equipment.
In addition, the means for transmitting the rotary motion of the sensor 14 in the measurement direction to the target support 24 define angular lost motion such that when the direction of rotation of the sensor is reversed, the sensor is free to rotate about the axis YY through an angle close to 180° so as to come face to face with the target 16. When such rotation of the sensor 14 in the opposite direction continues beyond 180°, then the rotation is again 20~~4~~
_8_ transmitted to the support 24 carrying the target 16 such that the sensor 14 remains face to face with the target. The sensor can be recalibrated or an analogous operation can then be performed under conditions which are substantially identical to measurement condi-tions, both with respect to the sensor-target distance and with respect to the direction and speed of the flow of the fluid present in the borehole between the sensor and the target.
In practice, in the embodiment in Figure 1 and in Figures 2A to 2D, the means for transmitting the rotary motion of the sensor to the target with angular lost motion limited to about 180° comprise two abutments 40a and 40b which project from the support plate 38 from the same side as the cylindrical rod 34, thereby being suitable for coming into abutment against opposite faces 41a and 41b of the block 24b. The two extreme positions correspond respectively to the abutment 40a bearing against the face 41a of the block, and to the abutment 40b bearing against the face 41b, and these positions are shown in Figures 2A and 2D respectively. They are separated by counterclockwise rotation of the sensor support plate 38 about the axis YY relative to the target support 24 and through about 180°.
The measurement equipment 10 shown in Figure 1 also includes means for rotating the sensor 14 either in a first direction for performing the desired measurement of the inside of the borehole or else in the opposite direction in order to recalibrate the sensor.
These drive means firstly comprise an inner hollow shaft 42 which is mounted to rotate inside the outer hollow shaft 20. The shaft 42 has its top end connected to a motor for imparting rotary drive (not shown) and associated with means for reversing the direction of rotation of said shaft. A cylindrical drive part 44 is received in the bottom end of the hollow shaft 42. This drive part includes a key 45 on its outside surface which is received in an axial groove 46 formed inside the shaft 42. The drive part 44 is thus constrained to rotate together with the shaft 42 while still being capable of being separated therefrom by being moved downwards, as described below.
The bottom end of the drive part 44 includes a flange 44a which is retained with a small amount of axial clearance between two washers 47 mounted in two circumferential grooves inside the tubular top portion 24a of the target support 24. This structure makes it possible normally to prevent the part 44 from moving in translation relative to the hollow drive shaft 42, while allowing said part 44 to be removed together with the target support 24 when the ring 26 is unscrewed.
The bottom face of the flange 44 carries two cylindrical rods 48a and 48b which are oriented parallel to the axis XX of the equip-ment and which are disposed at equal distances from said axis. The top face of the support plate 38 also carries two cylindrical rods 50a and 50b oriented parallel to the axis YY and equidistant from said axis. The distance between the axes 48a and 48b is the same as the distance between the axes 50a and 50b, as can be seen in Figures 2A to 2D.
Two parallel links 52a and 52b lying in a plane extending radially relative to the axes XX and YY are hinged at their ends to the ends of the cylindrical rods 48a and 50a, and 48b and 50b, res-pectively. The system constituted in this way forms a deformable parallelogram having two of its sides constituted by the links 52a and 52b for identically transmitting any rotation of the drive shaft 42 and of the part 44 to the support plate 38 of the sensor 14.
Advantageously, although it is not critical, the abutments 40a and 40b are formed by larger diameter portions formed at the bases of the cylindrical rods 50a and 50b, as shown in Figures 1 and 2.
By virtue of the above-described arrangement, when the drive shaft 42 rotates clockwise (as shown in Figure 2A) the abutment 40a normally bears against the side face 41a of the block 24b of support 24, such that the sensor 14 cannot rotate about the axis YY and the assembly constituted by the sensor 14 and the support 24 for the target 16 rotates in unison about the axis XX. The sensor 14 is then oriented radially towards the wall of the borehole. By causing the entire equipment 10 to move upwards simultaneously in transla-tion parallel to the axis XX, the sensor is caused to perform heli-cal motion, thereby enabling measurements to be performed.
When, at any moment either before measurement, or after measure-ment, or during measurement, it is desired to calibrate the sensor 14, it suffices, in accordance with the invention, to reverse the direction of rotation of the drive shaft 42.
~0~.~3~
As shown in Figures 2B and 2C, the drive shaft 20 then rotates the two cylindrical rods 48a and 48b counterclockwise about the axis XX. This rotary motion is transmitted, as before, to the plate 38 supporting the sensor 14 by means of the links 52a and 52b and via the cylindrical rods 50a and 50b. However, given that the direction of rotation has been reversed, the abutment 40a which was pressed against the face 41a of the block 24b moves away from this block such that rotation of the plate 38 is not transmitted to the target support 24. Consequently, under the effect of inertia and friction, relative rotation occurs between the plate 38 supporting the sensor 14 and the support 24 carrying the target 16, about the axis YY and as shown successively in Figures ZB and 2C.
As shown in Figure 2D, this rotation of the sensor 14 about the axis YY continues until the second abutment 40b abuts against the other face 41b of the block 24b. Advantageously, this abutting engagement occurs when the sensor 14 has rotated through 180° about its axis YY, such that it is then face to face with the target 16.
The sensor can then be recalibrated under conditions which are as close as possible to measurement conditions, since the distance between the sensor and the target is approximately equal to the distance between the sensor and the wall of the borehole during measurement and since the flow of the fluid contained in the bore-hole between the sensor and the target is a flow which occurs at practically the same speed and in the same direction as the flow of the fluid between the sensor and the wall during measurement.
Calibration actually takes place while the assembly constituted by the sensor and the target is rotating in unison about the axis XX of the equipment at the same speed as it rotates during measurement, but in the opposite direction, and only translation of the equipment parallel to the axis XX is generally stopped. Given that calibra-tion takes place in situ, environmental conditions such as tempera-ture and pressure are obviously the same as those which prevail during measurement.
In order to finish off the description of the equipment 10, it is specified (with reference to Figure 1) that electrical conductors 54 are placed inside the inner drive shaft 42 and pass through the part 44 in order to have one end connected to the plate 38 suppor-ting the sensor 14. The top ends of the electrical conductors 54 are connected to a conventional electrical module of the equipment (not shown) serving simultaneously to provide the sensor with the electrical signals it requires to operate and also to perform preliminary processing of the signals provided by the sensor.
The electrical conductors 54 rotate together with the shaft 42 and the part 44, and they include (at the top portion of the part 44) a connector suitable for allowing the support 24 carrying both the target 16 and the sensor 14 to be removed (connector not shown).
Electrical connection between the ends of the electrical conductors 54 connected to the plate 38 and the sensor 14 is provided by con-tacts which are automatically connected electrically when the sensor 14 is fixed on the support plate 38, while nevertheless allowing the sensor to be removed therefrom.
In a manner which is conventional for equipment used in bore-holes, the measuring equipment 10 shown in Figure 1 also includes means for sealing from the borehole medium the portion of the equip-ment situated inside its housing 18 above the part 44. These means comprise, in particular, two end rings 55 and 56 respectively con-nected in sealed manner on the housing 18 and on the outer hollow shaft 20, and a ring 57 connected to the ring 55 by an expandable bellows 58 and slidable on the ring 55.
Figures 3A and 3B show that the bottom portion of the measure-ment equipment 10 described with reference to Figure 1 is inter-changable, and thus the same equipment can be used for performing measurements in boreholes of different diameters.
Thus, Figures 3A and 3B show that the assembly constituted by the target support 24, the drive part 44, the target 16 fixed on the support 24, the plate 38 supporting the sensor 14, and the mechanism for transmitting rotary motion of the part 44 to the plate 38 and including, in particular, links 52a and 52b constitutes an inter-changable module. This module is removed merely by unscrewing the ring 26.
Each module is a different size suitable for performing measure-ments in boreholes of different diameters. More precisely, the tar-get support 24 defines the distance between the longitudinal axis XX
of the equipment and the axis of rotation YY of the sensor. Given 20114~'~
-lz-that the dimensions of the sensor 14 are, in practice, always the same, this distance increases with increasing borehole diameter so as to ensure that the distance d (Figure 1) between the sensor and the facing wall of the borehole while measurements are being perfor-med always lies within given limits which depend on the characteris-tics of the sensor and regardless of the diameter of the borehole.
In each module, the drive part 44 and the plate 38 supporting the sensor 14 are all identical, such that changes in the distance separating the axes XX and YY give rise merely to changes in the length, and optionally the shape, of the links 52.
Further, in order to ensure that the distance between the sensor 14 and the target 16 in the sensor-calibrating position always lies within said determined limits, so that said distance is approximate-ly equal to the distance between the sensor and the wall of the borehole in the measurement position, the target 16 is mounted in the support 24 in such a manner that the distance between said target and the axis YY is always practically the same, as can clearly be seen in Figures 3A and 3B.
It should be observed that the support 24 forms a closed cage beneath the sensor and the target, and behind the target it includes a portion in the form of a section of an arc of a circle centered on the axis XX and whose distance from the wall of the borehole is approximately constant, regardless of the diameter of the borehole.
Finally, in order to ensure that the equipment is centered in-side the borehole without too much difficulty, the various parts constituting the equipment, and in particular the rotary portion thereof, are designed to keep the assembly balanced as well as possible on a permanent basis about the axis XX of the equipment.
In the embodiment described above with reference to Figures 1 to 3, the sensor 14 is small enough to enable it to be brought face to face with the target 16 merely by being rotated about the axis YY
and without any interference occurring between the sensor and the wall of the borehole. However, when a larger sensor is used, it may be necessary to combine this rotary motion of the sensor about its axis with an additional motion for recentering the assembly formed by the sensor and the target relative to the axis XX of the equipment.
~Q~1~~~
A second embodiment of the invention putting this idea into effect is described with reference to Figures 4 and 5.
In this embodiment, the same reference numerals plus 100 are used for designating items having analogous functions.
The measurement equipment 110 shown in Figure 4A comprises a sensor 114 interchangeably mounted on a sensor support 138 hinged via two aligned pivots 134 about the axis YY to a target support 124. A target 116 is fixed on the target support 124 in such a manner that rotation of the sensor 114 through about 180° about the axis YY makes it possible to bring the sensor face to face with the target. The top face of the target support 124 includes a hollow cylindrical rod 125 which is received in a bore 127 formed in a rotary head 142 which is itself rotatable inside the outer tubular housing 118 of the equipment. More precisely, the axis ZZ of the bore 127 in which the rod 125 is received lies parallel to and is offset from the longitudinal axis XX of the measurement head 110, which axis XX constitutes the axis of rotation of the head 142.
In order to allow the sensor 114 to be driven in rotation when the rotary head 142 rotates about the axis XX, a U-shaped link 152 (more clearly visible in Figures 5A to 5C) is keyed at one of its ends to the end of the top pivot 134, and carries a stud 153 at its opposite end, which stud is received in a radial slot 155 formed in the bottom face of the rotary head 142. This link 152 which is disposed in a radial plane relative to the longitudinal axis XX of the equipment between the rotary head 142 and the target support 124 thus serves to transmit any rotary motion in either direction of the rotary head 142 to the sensor 114.
In addition, the axis of the radial slot 155 intersects the axes XX and ZZ and this groove is situated on the opposite side of the axis XX to the axis ZZ. In addition, the observation axis of the sensor 114 lies in a radial plane relative to the axis YY in which the axis of the stud 153 is situated such that when the sensor is oriented radially towards the wall of the borehole in which the equipment is placed, the axis of rotation ZZ of the target support 124 lies between the longitudinal axis XX of the equipment and the axis of rotation YY of the sensor (see Figures 4A and 5A). This position, which is the measurement position, is normally maintained _ 14 _ ~r~'.'..~a~~
during clockwise rotation of the head 142 as shown in Figure 5A by an abutment 140a fixed on the bottom face of the head coming into abutment against a complementary abutment 141 fixed on the top face of the target support (in Figures 5A to 5C, the outlines of the rotary head 142 and of the target support 124 are drawn respectively by means of a dot-dashed line and a solid line).
During clockwise rotation of the head 142 under the control of appropriate means (not shown) situated in the top portion of the equipment, the assembly comprising the target support 124, the target 116, the sensor support 138, and the sensor 114 rotates in unison about the longitudinal axis XX of the equipment. This rotation allows the sensor 114 to perform the desired measurements.
In accordance with the invention, when it is desired to bring the sensor face to face with the target, e.g. for calibrating the sensor within the borehole, then it suffices to reverse the direc-tion of rotation of the head 142. As shown successively in Figures 5B and 5C, the rotation of the head 142 is then transmitted only to the sensor 114 via the link 152. Under the effect of inertia and friction, the target support 124 tends to stop moving such that throughout this stage its orientation is assumed to remain unaltered in Figures 5A and 5C.
When the assembly constituted by the rotary head 142 and the sensor 114 has thus rotated through about 180[, about axes XX and YY
respectively, the axis ZZ about which the target support 124 rotates relative to the head 142 again lies in the same plane as the axes XX
and YY, but this time the axis XX lies between the axes YY and ZZ
(as shown in Figure 5C). As can be seen in Figures 4B and 4C, the sensor 114 then faces the target 116 and the assembly constituted by these two items is automatically recentered relative to the axis XX
of the equipment, such that the target 116 projects from one side and the sensor 114 projects from the opposite side of the head 142, by approximately the same amount. The sensor and the target are kept in this relative position during which the sensor can be cali-brated by the abutment 141 fixed on the top face of the target support 124 coming into abutment against a second abutment 140b placed on the bottom face of the rotary head 142, as can be seen in Figure 5C.
203.~.~~ ~'~
As in the first described embodiment, the distance then existing between the sensor 114 and the target 116 is designed to be approxi-mately equal to the distance which exists during measurement between the sensor and the wall of the borehole.
Advantageously, the measuring equipment 110 shown in Figures 4A
and 4B includes, as before, an interchangeable bottom portion ena-bling the equipment to be adapted to boreholes of different diame-ters. Similarly, the sensor 114 is mounted on its support 138 in removable manner in order to enable it to be replaced.
The sensor 114 is fed with electricity and the signals it deli-vers are transmitted by electrical conductors (not shown) passing through the rotary head 142, then inside the hollow cylindrical rod 125, and connected to the sensor via the support 138.
Finally, sealing means comparable to those used in the first embodiment are likewise provided.
Naturally, the invention is not limited to the embodiments described above by way of example, but it extends to any variant thereof.
Thus, in the embodiment shown in Figures 4 and 5, the rotary head 142 could be freely mounted inside the casing 116 of the equip-ment and the sensor 114 could be rotated directly on the target support rod 125 via a mechanism actuated by a rotary shaft placed inside the head 142. This mechanism may be a link mechanism as in the first embodiment. These mechanisms may also be replaced by any equivalent mechanism, e.g. of the universal joint type.
In addition, it will readily be understood that the angle through which reverse rotation can take place in order to bring the sensor face to face with the target need not to be 180°, the only condition that needs to be satisfied being that the angle should be sufficient to ensure that the target is hidden from the sensor while the sensor is rotating in the measurement direction.
Finally, the means for transmitting the rotary motion of the sensor to the target together with limited angular lost motion may be replaced by any other means for controlling relative displacement between the target and the sensor when the direction of rotation is reversed.
To this end, the target 16 has characteristics which are as close as possible to those of the casing 12 under inspection. The distance between the sensor and the target in the calibration position is as close as possible to the distance between the sensor and the casing 12 during measurement. And the fluids present in the borehole also have relatively comparable flow characteristics in both positions.
In the embodiment shown in Figures 1 to 3, the sensor 14 is sufficiently small for the above-specified conditions to be obtained merely by rotating the sensor 14 about an axis YY parallel to, and offset from, the longitudinal axis XX of the equipment.
As shown in greater detail in Figure 1, this result is obtained in practice by means of measurement equipment 10 including a non-rotating tubular outer housing 18 in which a hollow outer shaft 20 is rotatably mounted by means of two bearings 22. This hollow outer shaft 20 constitutes a rotary head which extends downwards beyond the bottom end of the housing 18 in order to support a target support 24 on which the target 16 is fixed.
More precisely, the target support 24 is removably fixed on a tubular bottom portion 20a of the hollow shaft 20, e.g. by means of a ring 26 screwed on a threaded tubular top portion 24a of the support 24 so as to clamp a flange 20b fixed to the shaft 20 against the top edge of the threaded tubular portion 24a. A stud 28 mounted in the threaded top end 24a of the support 24 projects radially inwardly into a longitudinal groove 30 formed in the tubular bottom portion 20a of the shaft 20 so as to prevent relative rotation occurring between the shaft and the support 24.
Thus, the assembly constituted by the outer hollow shaft 20 and the target support 24 is free to rotate relative to the outer housing 18 of the equipment about the longitudinal axis XX thereof.
''~~~~4~'~
Regardless of the angular position of this assembly, the target 16 is fixed on the support 24 in such a manner as to be permanently disposed parallel to the longitudinal axis XX of the equipment and to be situated at a constant distance from said axis.
At a location diametrically opposite the target 16 about the longitudinal axis XX of the equipment, the target support 24 includes a block 24b adjacent to the threaded tubular portion 24a and in which a bore 32 is formed about an axis YY which is parallel to and offset from the longitudinal axis XX of the equipment. A
cylindrical rod 34 is mounted to rotate in said bore 32 and is restrained from translation by a screw 26 engaged in the block 24b and having an end received in a groove in the cylindrical rod 34.
The bottom end of the cylindrical rod 34 is fixed to a support plate 38 extending radially relative to the axis XX and YY and constituting the support for the sensor 14. The sensor 14 is removably fixed on said support plate 38 by fixing means such as screws (not shown).
It should be observed that the distance d between the sensor 14 and the inside wall of the borehole when the sensor is directed radially towards said borehole relative to the axis XX is approxima-tely equal to the distance between the same sensor and the target 16 when the sensor is rotated through 180° about the axis YY, as shown in dot-dashed lines in Figure 1.
While measurement is being performed, the sensor 14 must be permanently directed towards the wall of the borehole, and the distance d between said sensor and the wall should remain constant.
Rotary drive for the sensor must therefore be transmitted to the entire target support 24 so that the sensor does not rotate about the axis YY and so that the sensor rotates in unison with the support 24 about the axis XX of the equipment.
In addition, the means for transmitting the rotary motion of the sensor 14 in the measurement direction to the target support 24 define angular lost motion such that when the direction of rotation of the sensor is reversed, the sensor is free to rotate about the axis YY through an angle close to 180° so as to come face to face with the target 16. When such rotation of the sensor 14 in the opposite direction continues beyond 180°, then the rotation is again 20~~4~~
_8_ transmitted to the support 24 carrying the target 16 such that the sensor 14 remains face to face with the target. The sensor can be recalibrated or an analogous operation can then be performed under conditions which are substantially identical to measurement condi-tions, both with respect to the sensor-target distance and with respect to the direction and speed of the flow of the fluid present in the borehole between the sensor and the target.
In practice, in the embodiment in Figure 1 and in Figures 2A to 2D, the means for transmitting the rotary motion of the sensor to the target with angular lost motion limited to about 180° comprise two abutments 40a and 40b which project from the support plate 38 from the same side as the cylindrical rod 34, thereby being suitable for coming into abutment against opposite faces 41a and 41b of the block 24b. The two extreme positions correspond respectively to the abutment 40a bearing against the face 41a of the block, and to the abutment 40b bearing against the face 41b, and these positions are shown in Figures 2A and 2D respectively. They are separated by counterclockwise rotation of the sensor support plate 38 about the axis YY relative to the target support 24 and through about 180°.
The measurement equipment 10 shown in Figure 1 also includes means for rotating the sensor 14 either in a first direction for performing the desired measurement of the inside of the borehole or else in the opposite direction in order to recalibrate the sensor.
These drive means firstly comprise an inner hollow shaft 42 which is mounted to rotate inside the outer hollow shaft 20. The shaft 42 has its top end connected to a motor for imparting rotary drive (not shown) and associated with means for reversing the direction of rotation of said shaft. A cylindrical drive part 44 is received in the bottom end of the hollow shaft 42. This drive part includes a key 45 on its outside surface which is received in an axial groove 46 formed inside the shaft 42. The drive part 44 is thus constrained to rotate together with the shaft 42 while still being capable of being separated therefrom by being moved downwards, as described below.
The bottom end of the drive part 44 includes a flange 44a which is retained with a small amount of axial clearance between two washers 47 mounted in two circumferential grooves inside the tubular top portion 24a of the target support 24. This structure makes it possible normally to prevent the part 44 from moving in translation relative to the hollow drive shaft 42, while allowing said part 44 to be removed together with the target support 24 when the ring 26 is unscrewed.
The bottom face of the flange 44 carries two cylindrical rods 48a and 48b which are oriented parallel to the axis XX of the equip-ment and which are disposed at equal distances from said axis. The top face of the support plate 38 also carries two cylindrical rods 50a and 50b oriented parallel to the axis YY and equidistant from said axis. The distance between the axes 48a and 48b is the same as the distance between the axes 50a and 50b, as can be seen in Figures 2A to 2D.
Two parallel links 52a and 52b lying in a plane extending radially relative to the axes XX and YY are hinged at their ends to the ends of the cylindrical rods 48a and 50a, and 48b and 50b, res-pectively. The system constituted in this way forms a deformable parallelogram having two of its sides constituted by the links 52a and 52b for identically transmitting any rotation of the drive shaft 42 and of the part 44 to the support plate 38 of the sensor 14.
Advantageously, although it is not critical, the abutments 40a and 40b are formed by larger diameter portions formed at the bases of the cylindrical rods 50a and 50b, as shown in Figures 1 and 2.
By virtue of the above-described arrangement, when the drive shaft 42 rotates clockwise (as shown in Figure 2A) the abutment 40a normally bears against the side face 41a of the block 24b of support 24, such that the sensor 14 cannot rotate about the axis YY and the assembly constituted by the sensor 14 and the support 24 for the target 16 rotates in unison about the axis XX. The sensor 14 is then oriented radially towards the wall of the borehole. By causing the entire equipment 10 to move upwards simultaneously in transla-tion parallel to the axis XX, the sensor is caused to perform heli-cal motion, thereby enabling measurements to be performed.
When, at any moment either before measurement, or after measure-ment, or during measurement, it is desired to calibrate the sensor 14, it suffices, in accordance with the invention, to reverse the direction of rotation of the drive shaft 42.
~0~.~3~
As shown in Figures 2B and 2C, the drive shaft 20 then rotates the two cylindrical rods 48a and 48b counterclockwise about the axis XX. This rotary motion is transmitted, as before, to the plate 38 supporting the sensor 14 by means of the links 52a and 52b and via the cylindrical rods 50a and 50b. However, given that the direction of rotation has been reversed, the abutment 40a which was pressed against the face 41a of the block 24b moves away from this block such that rotation of the plate 38 is not transmitted to the target support 24. Consequently, under the effect of inertia and friction, relative rotation occurs between the plate 38 supporting the sensor 14 and the support 24 carrying the target 16, about the axis YY and as shown successively in Figures ZB and 2C.
As shown in Figure 2D, this rotation of the sensor 14 about the axis YY continues until the second abutment 40b abuts against the other face 41b of the block 24b. Advantageously, this abutting engagement occurs when the sensor 14 has rotated through 180° about its axis YY, such that it is then face to face with the target 16.
The sensor can then be recalibrated under conditions which are as close as possible to measurement conditions, since the distance between the sensor and the target is approximately equal to the distance between the sensor and the wall of the borehole during measurement and since the flow of the fluid contained in the bore-hole between the sensor and the target is a flow which occurs at practically the same speed and in the same direction as the flow of the fluid between the sensor and the wall during measurement.
Calibration actually takes place while the assembly constituted by the sensor and the target is rotating in unison about the axis XX of the equipment at the same speed as it rotates during measurement, but in the opposite direction, and only translation of the equipment parallel to the axis XX is generally stopped. Given that calibra-tion takes place in situ, environmental conditions such as tempera-ture and pressure are obviously the same as those which prevail during measurement.
In order to finish off the description of the equipment 10, it is specified (with reference to Figure 1) that electrical conductors 54 are placed inside the inner drive shaft 42 and pass through the part 44 in order to have one end connected to the plate 38 suppor-ting the sensor 14. The top ends of the electrical conductors 54 are connected to a conventional electrical module of the equipment (not shown) serving simultaneously to provide the sensor with the electrical signals it requires to operate and also to perform preliminary processing of the signals provided by the sensor.
The electrical conductors 54 rotate together with the shaft 42 and the part 44, and they include (at the top portion of the part 44) a connector suitable for allowing the support 24 carrying both the target 16 and the sensor 14 to be removed (connector not shown).
Electrical connection between the ends of the electrical conductors 54 connected to the plate 38 and the sensor 14 is provided by con-tacts which are automatically connected electrically when the sensor 14 is fixed on the support plate 38, while nevertheless allowing the sensor to be removed therefrom.
In a manner which is conventional for equipment used in bore-holes, the measuring equipment 10 shown in Figure 1 also includes means for sealing from the borehole medium the portion of the equip-ment situated inside its housing 18 above the part 44. These means comprise, in particular, two end rings 55 and 56 respectively con-nected in sealed manner on the housing 18 and on the outer hollow shaft 20, and a ring 57 connected to the ring 55 by an expandable bellows 58 and slidable on the ring 55.
Figures 3A and 3B show that the bottom portion of the measure-ment equipment 10 described with reference to Figure 1 is inter-changable, and thus the same equipment can be used for performing measurements in boreholes of different diameters.
Thus, Figures 3A and 3B show that the assembly constituted by the target support 24, the drive part 44, the target 16 fixed on the support 24, the plate 38 supporting the sensor 14, and the mechanism for transmitting rotary motion of the part 44 to the plate 38 and including, in particular, links 52a and 52b constitutes an inter-changable module. This module is removed merely by unscrewing the ring 26.
Each module is a different size suitable for performing measure-ments in boreholes of different diameters. More precisely, the tar-get support 24 defines the distance between the longitudinal axis XX
of the equipment and the axis of rotation YY of the sensor. Given 20114~'~
-lz-that the dimensions of the sensor 14 are, in practice, always the same, this distance increases with increasing borehole diameter so as to ensure that the distance d (Figure 1) between the sensor and the facing wall of the borehole while measurements are being perfor-med always lies within given limits which depend on the characteris-tics of the sensor and regardless of the diameter of the borehole.
In each module, the drive part 44 and the plate 38 supporting the sensor 14 are all identical, such that changes in the distance separating the axes XX and YY give rise merely to changes in the length, and optionally the shape, of the links 52.
Further, in order to ensure that the distance between the sensor 14 and the target 16 in the sensor-calibrating position always lies within said determined limits, so that said distance is approximate-ly equal to the distance between the sensor and the wall of the borehole in the measurement position, the target 16 is mounted in the support 24 in such a manner that the distance between said target and the axis YY is always practically the same, as can clearly be seen in Figures 3A and 3B.
It should be observed that the support 24 forms a closed cage beneath the sensor and the target, and behind the target it includes a portion in the form of a section of an arc of a circle centered on the axis XX and whose distance from the wall of the borehole is approximately constant, regardless of the diameter of the borehole.
Finally, in order to ensure that the equipment is centered in-side the borehole without too much difficulty, the various parts constituting the equipment, and in particular the rotary portion thereof, are designed to keep the assembly balanced as well as possible on a permanent basis about the axis XX of the equipment.
In the embodiment described above with reference to Figures 1 to 3, the sensor 14 is small enough to enable it to be brought face to face with the target 16 merely by being rotated about the axis YY
and without any interference occurring between the sensor and the wall of the borehole. However, when a larger sensor is used, it may be necessary to combine this rotary motion of the sensor about its axis with an additional motion for recentering the assembly formed by the sensor and the target relative to the axis XX of the equipment.
~Q~1~~~
A second embodiment of the invention putting this idea into effect is described with reference to Figures 4 and 5.
In this embodiment, the same reference numerals plus 100 are used for designating items having analogous functions.
The measurement equipment 110 shown in Figure 4A comprises a sensor 114 interchangeably mounted on a sensor support 138 hinged via two aligned pivots 134 about the axis YY to a target support 124. A target 116 is fixed on the target support 124 in such a manner that rotation of the sensor 114 through about 180° about the axis YY makes it possible to bring the sensor face to face with the target. The top face of the target support 124 includes a hollow cylindrical rod 125 which is received in a bore 127 formed in a rotary head 142 which is itself rotatable inside the outer tubular housing 118 of the equipment. More precisely, the axis ZZ of the bore 127 in which the rod 125 is received lies parallel to and is offset from the longitudinal axis XX of the measurement head 110, which axis XX constitutes the axis of rotation of the head 142.
In order to allow the sensor 114 to be driven in rotation when the rotary head 142 rotates about the axis XX, a U-shaped link 152 (more clearly visible in Figures 5A to 5C) is keyed at one of its ends to the end of the top pivot 134, and carries a stud 153 at its opposite end, which stud is received in a radial slot 155 formed in the bottom face of the rotary head 142. This link 152 which is disposed in a radial plane relative to the longitudinal axis XX of the equipment between the rotary head 142 and the target support 124 thus serves to transmit any rotary motion in either direction of the rotary head 142 to the sensor 114.
In addition, the axis of the radial slot 155 intersects the axes XX and ZZ and this groove is situated on the opposite side of the axis XX to the axis ZZ. In addition, the observation axis of the sensor 114 lies in a radial plane relative to the axis YY in which the axis of the stud 153 is situated such that when the sensor is oriented radially towards the wall of the borehole in which the equipment is placed, the axis of rotation ZZ of the target support 124 lies between the longitudinal axis XX of the equipment and the axis of rotation YY of the sensor (see Figures 4A and 5A). This position, which is the measurement position, is normally maintained _ 14 _ ~r~'.'..~a~~
during clockwise rotation of the head 142 as shown in Figure 5A by an abutment 140a fixed on the bottom face of the head coming into abutment against a complementary abutment 141 fixed on the top face of the target support (in Figures 5A to 5C, the outlines of the rotary head 142 and of the target support 124 are drawn respectively by means of a dot-dashed line and a solid line).
During clockwise rotation of the head 142 under the control of appropriate means (not shown) situated in the top portion of the equipment, the assembly comprising the target support 124, the target 116, the sensor support 138, and the sensor 114 rotates in unison about the longitudinal axis XX of the equipment. This rotation allows the sensor 114 to perform the desired measurements.
In accordance with the invention, when it is desired to bring the sensor face to face with the target, e.g. for calibrating the sensor within the borehole, then it suffices to reverse the direc-tion of rotation of the head 142. As shown successively in Figures 5B and 5C, the rotation of the head 142 is then transmitted only to the sensor 114 via the link 152. Under the effect of inertia and friction, the target support 124 tends to stop moving such that throughout this stage its orientation is assumed to remain unaltered in Figures 5A and 5C.
When the assembly constituted by the rotary head 142 and the sensor 114 has thus rotated through about 180[, about axes XX and YY
respectively, the axis ZZ about which the target support 124 rotates relative to the head 142 again lies in the same plane as the axes XX
and YY, but this time the axis XX lies between the axes YY and ZZ
(as shown in Figure 5C). As can be seen in Figures 4B and 4C, the sensor 114 then faces the target 116 and the assembly constituted by these two items is automatically recentered relative to the axis XX
of the equipment, such that the target 116 projects from one side and the sensor 114 projects from the opposite side of the head 142, by approximately the same amount. The sensor and the target are kept in this relative position during which the sensor can be cali-brated by the abutment 141 fixed on the top face of the target support 124 coming into abutment against a second abutment 140b placed on the bottom face of the rotary head 142, as can be seen in Figure 5C.
203.~.~~ ~'~
As in the first described embodiment, the distance then existing between the sensor 114 and the target 116 is designed to be approxi-mately equal to the distance which exists during measurement between the sensor and the wall of the borehole.
Advantageously, the measuring equipment 110 shown in Figures 4A
and 4B includes, as before, an interchangeable bottom portion ena-bling the equipment to be adapted to boreholes of different diame-ters. Similarly, the sensor 114 is mounted on its support 138 in removable manner in order to enable it to be replaced.
The sensor 114 is fed with electricity and the signals it deli-vers are transmitted by electrical conductors (not shown) passing through the rotary head 142, then inside the hollow cylindrical rod 125, and connected to the sensor via the support 138.
Finally, sealing means comparable to those used in the first embodiment are likewise provided.
Naturally, the invention is not limited to the embodiments described above by way of example, but it extends to any variant thereof.
Thus, in the embodiment shown in Figures 4 and 5, the rotary head 142 could be freely mounted inside the casing 116 of the equip-ment and the sensor 114 could be rotated directly on the target support rod 125 via a mechanism actuated by a rotary shaft placed inside the head 142. This mechanism may be a link mechanism as in the first embodiment. These mechanisms may also be replaced by any equivalent mechanism, e.g. of the universal joint type.
In addition, it will readily be understood that the angle through which reverse rotation can take place in order to bring the sensor face to face with the target need not to be 180°, the only condition that needs to be satisfied being that the angle should be sufficient to ensure that the target is hidden from the sensor while the sensor is rotating in the measurement direction.
Finally, the means for transmitting the rotary motion of the sensor to the target together with limited angular lost motion may be replaced by any other means for controlling relative displacement between the target and the sensor when the direction of rotation is reversed.
Claims (21)
1. A logging method using a sensor fitted to equipment suitable for use in a borehole, comprising a measurement step in which the sensor is caused to rotate in a given direction in order to scan the wall of the borehole circumferentially, and a calibration step in which the sensor and a calibration target are brought face to face by reversing the direction of rotation of the sensor, whereby a reference measurement for calibrating the sensor can be obtained.
2. A method according to claim 1, wherein the distance between the sensor and the target during the calibration step is substantially equal to the distance between the sensor and the wall of the borehole during the measurement step.
3. A method according to claim 1 or 2, wherein the sensor is rotated during the measurement step about an axis which is substantially parallel to the longitudinal direction of the borehole, and during the calibration step, the sensor and the target are brought face to face substantially perpendicularly to said longitudinal direction.
4. A method according to claim 3, wherein a target is used having limited angular lost motion relative to the sensor such that during a measurement step, the rotation of the sensor in said one direction is transmitted to the target occupying a first angular position offset angularly relative to the sensor, and that when the direction of rotation of the sensor is reversed, this rotary motion is transmitted to the target occupying a second angular position facing the sensor after said angular lost motion has been taken up.
5. A method according to claim 4, wherein the sensor is mounted to rotate on a support carrying the target by means of a first axis (YY) parallel to and offset from a longitudinal axis (XX) of the equipment, such that when the rotary motion of the sensor is transmitted to the target in the first direction and in the opposite direction the assembly formed by the sensor, the support, and the target rotates in unison about said longitudinal axis (XX) and that, while said angular lost motion is being taken up, the sensor rotates about the first axis (YY) relative to the support.
6. A method according to claim 5, wherein the support carrying the target is rotatably mounted on a head to rotate about a second axis (ZZ) parallel to and offset from the first axis (YY) and the longitudinal axis (XX) of the equipment, the head being itself rotatable about said longitudinal axis (XX), such that while said angular lost motion is being taken up, rotation of the sensor about the first axis (YY) is combined with recentering of the assembly constituted by the target and the sensor relative to said longitudinal axis (XX).
7. A method according to any one of claims 4 to 6, wherein rotary drive is applied directly to the sensor.
8. A method according to claim 6, wherein rotary drive is applied directly to the head.
9. Logging apparatus suitable for use in a borehole, the apparatus comprising a housing, a sensor mounted on a rotary head rotatable about a longitudinal axis (XX) of the housing, and drive means for rotating the sensor about said axis in one direction to scan the wall of the borehole, the apparatus further comprising:
a calibration target mounted on said rotary head;
and displacement means responsive to the direction of rotation of the sensor in order to displace the sensor and the target relative to each other from a measurement position in which the sensor is oriented towards the wall of the borehole to a calibration position in which the sensor is face to face with the target, whenever the direction of rotation is reversed.
a calibration target mounted on said rotary head;
and displacement means responsive to the direction of rotation of the sensor in order to displace the sensor and the target relative to each other from a measurement position in which the sensor is oriented towards the wall of the borehole to a calibration position in which the sensor is face to face with the target, whenever the direction of rotation is reversed.
10. Apparatus according to claim 9, wherein the displacement means comprise motion transmission means defining limited angular lost motion such that when the sensor rotates in said one direction, the target occupies a measurement position which is angularly offset relative to the sensor and when the sensor rotates in the opposite direction, the target occupies the calibration position.
11. Apparatus according to claim 10, wherein the limited angular lost motion corresponds to rotation through about 180°.
12. Apparatus according to claim 10 or 11, comprising a rotary head carrying a target support and rotatable about the longitudinal axis (XX) of the housing, the sensor being supported by the target support to rotate about a first axis (YY) parallel to and offset from said longitudinal axis (XX).
13. Apparatus according to claim 12, wherein the target support is mounted on the rotary head in interchangeable manner such that the distance between the first axis (YY) and said longitudinal axis (XX) can be selected as a function of the diameter of the borehole, so as to ensure that the distance (d) between the sensor and the wall of the borehole lies within predetermined limits when the sensor rotates in the measurement direction.
14. Apparatus according to claim 13, wherein the target is fixed on the target support in such a manner that the distance between the sensor and the target lies between said predetermined limits when the sensor is rotating in said opposite direction.
15. Apparatus according to any one of claims 12 to 14, wherein the sensor is removably fixed on a sensor support rotatable on the target support about the first axis (YY).
16. Apparatus according to any one of claims 12 to 15, wherein the target support is fixed on the rotary head, with the motion transmission means being placed between the sensor and the target support.
17. Apparatus according to claim 16, wherein the drive means for rotating the sensor comprise a drive shaft mounted along said longitudinal axis (XX) inside the rotary head, and a transmission mechanism for transmitting the rotary motion of said shaft to the sensor.
18. Apparatus according to claim 17, wherein said transmission mechanism comprises two links which are parallel to each other and whose ends are hinged on two pairs of studs fixed respectively on the drive shaft and on the sensor.
19. Apparatus according to any one of claims 12 to 15, wherein the target support is supported by the rotary head to rotate about a second axis (ZZ) parallel to and offset from both the first axis (YY) and said longitudinal axis (XX), said second axis being situated between the first axis and the longitudinal axis when the sensor rotates in the measurement direction, said motion transmission means being placed between the rotary head and the target support.
20. Apparatus according to claim 19, wherein the drive means for rotating the sensor comprise the rotary head and a transmission mechanism for transmitting the rotary motion of the rotary head to the sensor.
21. Apparatus according to claim 20, wherein said transmission mechanism comprises a link having one end fixed to a drive shaft of the sensor constituting the first axis (YY), and whose opposite end carries a stud received in a radial groove formed in the rotary head.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8903535 | 1989-03-17 | ||
| FR8903535A FR2644591B1 (en) | 1989-03-17 | 1989-03-17 | LOGGING METHOD AND DEVICE USING A SENSOR PERFORMING A CIRCUMFERENTIAL SCANNING OF A WELLBORE WALL, PARTICULARLY IN ORDER TO CALIBRATE THIS SENSOR |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2011437A1 CA2011437A1 (en) | 1990-09-17 |
| CA2011437C true CA2011437C (en) | 2000-03-14 |
Family
ID=9379809
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002011437A Expired - Lifetime CA2011437C (en) | 1989-03-17 | 1990-03-05 | Logging method and apparatus using a rotating sensor |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4970695A (en) |
| EP (1) | EP0388315B1 (en) |
| AU (1) | AU630167B2 (en) |
| CA (1) | CA2011437C (en) |
| DE (1) | DE69000311T2 (en) |
| DK (1) | DK0388315T3 (en) |
| FR (1) | FR2644591B1 (en) |
| NO (1) | NO300399B1 (en) |
Families Citing this family (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5072388A (en) * | 1990-01-31 | 1991-12-10 | Union Oil Company Of California | Lined casing inspection method |
| US5146432A (en) * | 1991-08-05 | 1992-09-08 | Schlumberger Technology Corporation | Method for making cement impedance measurements with characterized transducer |
| US5732776A (en) * | 1995-02-09 | 1998-03-31 | Baker Hughes Incorporated | Downhole production well control system and method |
| US6442105B1 (en) | 1995-02-09 | 2002-08-27 | Baker Hughes Incorporated | Acoustic transmission system |
| US5706896A (en) | 1995-02-09 | 1998-01-13 | Baker Hughes Incorporated | Method and apparatus for the remote control and monitoring of production wells |
| US5676213A (en) * | 1996-04-10 | 1997-10-14 | Schlumberger Technology Corporation | Method and apparatus for removing mudcake from borehole walls |
| US5996711A (en) | 1997-04-14 | 1999-12-07 | Schlumberger Technology Corporation | Method and apparatus for locating indexing systems in a cased well and conducting multilateral branch operations |
| US5874676A (en) * | 1997-05-12 | 1999-02-23 | Maki, Jr.; Voldi E. | Method and apparatus for acoustically investigating a casing with a swept frequency pulse |
| US5995447A (en) * | 1997-05-14 | 1999-11-30 | Gas Research Institute | System and method for processing acoustic signals to image behind reflective layers |
| US6125079A (en) * | 1997-05-14 | 2000-09-26 | Gas Research Institute | System and method for providing dual distance transducers to image behind an acoustically reflective layer |
| US6021093A (en) * | 1997-05-14 | 2000-02-01 | Gas Research Institute | Transducer configuration having a multiple viewing position feature |
| US6002639A (en) * | 1997-05-14 | 1999-12-14 | Gas Research Institute | Sensor configuration for nulling reverberations to image behind reflective layers |
| US6098017A (en) * | 1997-09-09 | 2000-08-01 | Halliburton Energy Services, Inc. | Adjustable head assembly for ultrasonic logging tools that utilize a rotating sensor subassembly |
| JP2000216188A (en) | 1999-01-22 | 2000-08-04 | Seiko Epson Corp | Wire bonding method, semiconductor device, circuit board, electronic apparatus, and wire bonder |
| US6466513B1 (en) | 1999-10-21 | 2002-10-15 | Schlumberger Technology Corporation | Acoustic sensor assembly |
| US20060067162A1 (en) * | 2004-09-29 | 2006-03-30 | Blankinship Thomas J | Ultrasonic cement scanner |
| US7296927B2 (en) * | 2005-04-07 | 2007-11-20 | Halliburton Energy Services, Inc. | Laboratory apparatus and method for evaluating cement performance for a wellbore |
| US7380466B2 (en) * | 2005-08-18 | 2008-06-03 | Halliburton Energy Services, Inc. | Apparatus and method for determining mechanical properties of cement for a well bore |
| US7549320B2 (en) * | 2007-01-11 | 2009-06-23 | Halliburton Energy Services, Inc. | Measuring cement properties |
| US7621186B2 (en) | 2007-01-31 | 2009-11-24 | Halliburton Energy Services, Inc. | Testing mechanical properties |
| US8601882B2 (en) | 2009-02-20 | 2013-12-10 | Halliburton Energy Sevices, Inc. | In situ testing of mechanical properties of cementitious materials |
| US8783091B2 (en) | 2009-10-28 | 2014-07-22 | Halliburton Energy Services, Inc. | Cement testing |
| US8960013B2 (en) | 2012-03-01 | 2015-02-24 | Halliburton Energy Services, Inc. | Cement testing |
| US8794078B2 (en) | 2012-07-05 | 2014-08-05 | Halliburton Energy Services, Inc. | Cement testing |
| CA2926489C (en) * | 2013-11-12 | 2017-10-17 | Xueyu PANG | Validation of cased-hole acoustic tools |
| EP3714685A1 (en) | 2019-03-25 | 2020-09-30 | Trioliet B.V. | Device for processing crop, animal feed or components, electronic nir sensor system and method for calibrating |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2631270A (en) * | 1947-05-19 | 1953-03-10 | Eastman Oil Well Survey Co | Method of and apparatus for the measurement of distance or time interval by the use of compressional waves in the so-called supersonic range |
| US4524433A (en) * | 1981-03-10 | 1985-06-18 | Standard Oil Company (Indiana) | High speed sonic logging using multiple transducers |
| CA1185351A (en) * | 1981-03-10 | 1985-04-09 | Robert A. Broding | Borehole televiewer system using multiple transducer subsystems |
| FR2569859B1 (en) * | 1984-09-05 | 1986-08-29 | Schlumberger Prospection | LOGGING METHOD AND DEVICE FOR THE ACOUSTIC INSPECTION OF A BORING WITH A TUBING |
-
1989
- 1989-03-17 FR FR8903535A patent/FR2644591B1/en not_active Expired - Fee Related
-
1990
- 1990-03-05 CA CA002011437A patent/CA2011437C/en not_active Expired - Lifetime
- 1990-03-16 AU AU51428/90A patent/AU630167B2/en not_active Ceased
- 1990-03-16 NO NO901234A patent/NO300399B1/en not_active IP Right Cessation
- 1990-03-16 DK DK90400725.9T patent/DK0388315T3/en active
- 1990-03-16 DE DE9090400725T patent/DE69000311T2/en not_active Expired - Fee Related
- 1990-03-16 EP EP90400725A patent/EP0388315B1/en not_active Expired - Lifetime
- 1990-03-16 US US07/494,721 patent/US4970695A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US4970695A (en) | 1990-11-13 |
| FR2644591B1 (en) | 1991-06-21 |
| DK0388315T3 (en) | 1993-01-25 |
| DE69000311D1 (en) | 1992-10-22 |
| AU630167B2 (en) | 1992-10-22 |
| DE69000311T2 (en) | 1993-04-15 |
| AU5142890A (en) | 1990-09-20 |
| EP0388315A1 (en) | 1990-09-19 |
| NO300399B1 (en) | 1997-05-20 |
| NO901234L (en) | 1990-09-18 |
| CA2011437A1 (en) | 1990-09-17 |
| EP0388315B1 (en) | 1992-09-16 |
| NO901234D0 (en) | 1990-03-16 |
| FR2644591A1 (en) | 1990-09-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDC | Discontinued application reinstated | ||
| MKEX | Expiry |