JPH11183637A - Video inspection of layer-inspecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously observe both visual fields by providing a light- emitting diode(LED) for edge part and side part visual fields as a lighting means, forming an image by an optical system, and receiving light by a camera using a CCD array. SOLUTION: An optical module 28 is provided with a CCD camera 34 using a CCD array 36, and an optical group 40 with an objective lens is provided ahead of it. An optical block 42 is provided at the lower portion of the optical group 40 and one portion of an optical system for side part visual field and a pressure resistant window is formed. An optical system 44 for the edge part visual field is provided at the lower portion of the optical block 42, thus forming the pressure resistant window. The optical block 42 is fixed between flanges 46 and 48, and a plurality of LEDs 50 and 52 are arranged on each flange in a circumferential direction as a side part visual field lighting system. An LED 54 is provided on the end face of the flange 48 by surrounding the optical system 44 for the edge part visual field as an edge part visual field lighting system, thus observing both the edge part and side part visual fields.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video inspection or logging apparatus for inspecting the inside of a pipeline or searching a well for searching for corrosion.

[0002]

2. Description of the Related Art Video logging tools or video logging devices are used to inspect the side walls of boreholes or wells or, if the well is casingd, its casing. The device is also used for looking down the well. The device is capable of monitoring formation fluids generated by oil or gas wells. These formation fluids are typically some combination of oil, gas, and water. If only dark oil is being generated, these video logging devices are not very effective. Because the oil is essentially opaque over the distance required to make a useful observation. However, if only oil is produced,
The wells are probably in good condition and there is less need to make observations.

[0003] A more interesting case is when oil and water are produced together. In this case, such a device can exhibit an oil bubble flowing upward through the water. The water provides sufficient clarity so that it is possible to observe the column or wellbore side wall or casing of the produced fluid. Similarly, it is possible to see holes in the casing through which the formation fluid is produced.

[0004] Video logging devices are known. One such device provides an end view that views the wellbore axially down into a column of formation fluid being produced. This end view has a view large enough to include a portion of the well or casing wall surrounding the column of formation fluid. However, the axial length of the part of the wall that can be observed is somewhat limited.

[0005] Video logging devices are also known to provide a side view directed to the wellbore wall. While such devices provide better images of wells or casing walls with holes, they lack a well or end view of the well fluid produced above.

[0006] Known video logging devices typically use an incandescent lamp, which is a halogen lamp, to illuminate an end view or side view. Such lamps turn on relatively slowly because the incandescent filament needs to be heated and cooled. In addition, incandescent lamps require significant power, which is a drawback in downhole tools.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has been made in consideration of the above-mentioned problems, and has been made in view of the above-mentioned problems. It is intended to provide a layer device. It is another object of the present invention to provide such an apparatus with improved optics. It is yet another object of the present invention to provide a video logging device having both an edge viewing device and a side viewing device.

[0008]

In accordance with one aspect of the present invention, a video logging device is mounted in a housing dimensioned to be moved down and up through a borehole or wellbore. Video camera. The apparatus has both end viewing and side viewing optics, and has means for illuminating both the end viewing zone and the side viewing zone. Preferably, the lighting means comprises a plurality of light emitting diodes (LEDs). The end view and side view are imaged on the same image plane in the camera, and a charge-coupled device (CCD) array is located in the image plane. The end view and the side view can be taken simultaneously.

According to another aspect of the present invention, there is no end viewing optics, but the side viewing optics are arranged in a particular manner. In particular, the side-view optics comprises a block, preferably made of sapphire or silica, with an outer coating of sapphire. The block has an internal concave surface coated with a mirror that reflects the side view towards the camera. A camera lens group focuses the lateral field of view onto a CCD array in the image plane of the camera.

In another embodiment of the invention, the side viewing optics comprises two or three fisheye lenses,
It has a prism that transmits two or three side images separately to the camera. As used herein, the term "video" is not used to imply any particular video format, such as composite video used in NTSC or other formats.

[0011]

Referring to the drawings, FIG. 1 shows a video well logging device 10 according to the present invention, which is suspended in a borehole or well 12 by a cable 14. The cable extends through a pulley 16 at the surface of the ground and is wound on a drum 18;
Thereby, the apparatus is lowered or raised into the well 12. The drum 18 is connected to a drum and a surface device 20 that controls the operation of the device 10. Ground surface device 2
0 also supplies power to the device.

The well 12 is an oil or gas well and has a casing 22 fixed at 24 to a formation 26. The apparatus 10 comprises a lower optical module 28 (which will be described in connection with FIG. 2), a control module 30,
It has a telemetry module 32 for transmitting video images to the surface for further processing and subsequent display at the surface device 20.

The optical module 28 has a CC
A CCD camera 34 having a D array 36 is provided. An optical group 40 is arranged in front of the camera 34, which has an objective lens for said camera. The optical block 42 is arranged below the objective lens group 40 and forms a part of the side view optical system and the pressure-resistant window. An end view optical system 44 is disposed below the optical block 42 and forms a pressure-resistant window. The optical block 42 is fixed between the flanges 46 and 48, on each of which a plurality of light emitting diodes (LEDs) 50 and 52 are arranged circumferentially around the flange. ing. LED50
And 52 have a side illumination system for illuminating a side zone up to the casing 22 near the side view optical block 42.

Another ring of LEDs 54 is located on the end face of lower flange 48 and surrounds end viewing optics 44. The LEDs 54 constitute an edge illumination system for illuminating an edge zone below the edge viewing optical system 44.

The control module 30 includes a camera 34 and an LE.
It has a power supply and a driver 56 for D50, 52, 54. The control module further includes signal conditioning means 58 for taking the output signal from the camera 34, digitizing and processing the camera output signal and compressing it for transmission to the surface by the telemetry module 32.
have.

FIG. 2 shows the optical system of the optical module 28 in more detail. The camera lens group 40 has a doublet 62, a plano-convex lens 64, and a biconcave lens 66. The optical block 42, which forms part of both the side and end vision systems, has a flat upper surface 6
8 and a hemispherical concave lower surface 70. The concave surface 70 is coated with a mirror 72 comprised of an aluminum, silver or dielectric coating selected for the illumination wavelength of the LEDs 50,52,54. The central aperture 74 is not coated with the mirror,
The end viewing optics that allows the end viewing light beam to pass therethrough has an end window 44 formed by a concave and convex meniscus lens. The second concave / convex meniscus lens 76 further forms not only the concave surface of the block 42 in the aperture 74 but also a part of the end view optical system. Finally, a bifocal correction lens 78 is disposed on the upper flat surface of the optical block 42.
The lens has an inner portion 78 through which the end viewing rays pass.
a and a peripheral portion 78b through which the side view light beam passes.

Optical block 42 is held in place by three struts 80, only one of which is shown in cross-section in FIG. It is connected.

The LEDs 50, 52, 54 preferably emit in the near infrared region having a dominant wavelength of 880 nm in the example shown. Near infrared penetrates oils better than visible light. This is because Auzerais and S.
US patent application Ser. No. 08/483, croeder.
137. Furthermore, the LEDs turn on and off quickly, and thus can be operated at a relatively low duty cycle, thereby reducing power consumption. The LED also allows for stop action photography.

The optical system described above uses a commercially available software package called Code V, marketed by Optical Research Associates, Inc. of Pasadena, Calif., In well fluids such as oil and water. Designed and optimized for use with 880 nm light. The side view in the oil and water ranges from about +45 degrees to -45 degrees. In oil or gas wells that are casing with a 6 inch diameter casing, this provides a side view that is approximately 6 inches in height and circumferentially throughout the casing.

The end viewing optics provides a conical view in oil and water of about ± 35 degrees. The dimensions of the aperture 74 are
It has been selected to achieve the desired field of view for its side field of view. Edge viewing optics are those that provide a desired field of view for a given aperture.

The above-described optical system is substantially composed of the optical block 4
2 provides a depth of view for the side view from the outer side surface to the wall of the 6 inch casing. The field depth for the end field is approximately from the end window 44 to almost infinity.

The optical block 42 and the end window 44 must be pressure resistant and capable of withstanding abrasion. Preferably, they consist of sapphire, but alternatively consist of fused silica whose outer surface is coated with sapphire.

The optical system provides both side and end fields with C
It is arranged to form an image on the same surface that is the surface of the CD array 36. The image seen by the CCD 36 is shown in FIG. This represents a 6-inch pipe simulating a 6-inch casing, which is graduated by circumferential lines 1 inch apart and 16 equally spaced circumferentially. It is graduated by vertical or axial lines. This image is the end view 8
2, a side view 84 and a "dead zone" 86 between the end view and the side view. The central circle 88 is the end of the pipe. The obstruction caused by strut 80 is shown as 89 in FIG.

The side field of view 84 reflected from the mirror 82
Are reversed on the left and right as indicated by numerals 1, 3, and 5 in the figure. Due to the curvature of the hemispherical mirror 72, the side view is also distorted in the vertical or axial direction of the pipe.

FIG. 4 shows the image after the image of FIG. 3 has been transmitted to the surface of the ground and processed in the ground surface device 20 to convert the side field of view to linear coordinates and removing the distortion at that time. The same software package Code V can be used to perform this linear transformation.

FIG. 5 illustrates the image to object plane conversion used to go from the image of FIG. 3 to the image of FIG. FIG. 5 shows points along the image plane on the vertical axis and points along the object plane on the horizontal axis. Code V can be used to generate a look-up table to provide a correspondence between points on the image plane (FIG. 3) and points on the object plane (FIG. 4). The look-up table also
As can be seen by the numbers 1, 3 and 5 in FIG.

In some cases, it may be desirable to suspend a rotary flow meter below the video logging device of the present invention. The weight of the rotating body and the torsion created thereby may require that the video logging device be reinforced. It is possible to increase the dimensions of the struts 80 of the embodiment shown in FIG. 2, but this will increase the obstruction of the lateral vision.

FIG. 6 shows another embodiment of the present invention.
It increases mechanical strength while maintaining an acceptable circumferential side view. FIG. 6 shows the optical module 128 of the device, which has a CCD in its image plane.
It has a CCD camera 134 with an array 136. The apparatus comprises an outer lens group 144a and an inner lens group 144b, which are composed of a plurality of elements.
Has an optical system for an end view provided with a fish-eye lens 144 having The device further comprises side-view optics having left and right fisheye lenses 143 and 145, each of which is connected to an external lens group 14
3a, 145a and inner lens groups 143b, 14
5b, which are all composed of a plurality of elements. A plurality of LEDs 150 are fisheye lens 143
And 145 are arranged circumferentially around the optical module 128 and above the second plurality of LEDs 1.
52 is similarly disposed below the fisheye lens. Another plurality of LEDs 154 are arranged in a ring around the end view lens 144. LED 150 and 1
52 illuminates the side view and LED 154 illuminates the end view. As in the embodiment of FIG.
D has a dominant wavelength of 880 nm in the near infrared region.

In the embodiment of FIG. 2, the end view image and the side view image are concentric. This allows many of the end-view and side-view optics to be common, but the rays from the end-view and side-view will follow these common paths along different paths. Propagates through the optical element. In the embodiment of FIG. 6, the left and right views must be separated from each other and also from the end views. These three fields of view are imaged on the same image plane constituted by the CCD array 136.

The left, right, and end views are laterally separated from each other by a prism 181 shown in FIGS. Left and right fisheye lenses 143, 145
Each of the end view optical systems 144 and 154 has an objective lens for the CCD camera 134. Unlike the embodiment of FIG. 2, in the embodiments of FIGS. 6 and 7, each field has its own camera lens to image the corresponding field in the plane of the CCD array 136. I have. This is illustrated in FIG. 7, which also shows a prism 181 for separating the three fields of view.

The central ray path for each field of view will be briefly described. Light rays from the right fisheye lens 145 are reflected upward from the prism surface 183 toward the camera lens 159. The light from left fisheye lens 143 is
3 is reflected downwardly toward surface 185, and the ray is reflected laterally toward surface 187 and upwardly toward camera lens 157. Light rays from the edge viewing optics 144, 154 are reflected laterally at the prism surface 189 and again at the surface 191 and finally upward at the surface 193 to reach the camera lens 155. Figure 8 for all three fields
The left and right view images are shown at 143d and 145d, and the end view images are shown at 144d, as shown in the array map of FIG. 6 and 7 provide a circumferential field of view that is somewhat less than 360 degrees, depending on the configuration of the fisheye lens. As shown in the embodiment of FIGS. 9 and 10, it is possible to obtain a complete 360 ° field of view with three fisheye lenses arranged at 120 ° intervals from each other. These three fisheye lenses are 202, 20
4, 206 and mounted within housing 208. A prism 210 is disposed in the middle of the housing and reflects the three side view images toward a camera (not shown).

The prism 210 is shown in more detail in FIG. It has the shape of a truncated triangular pyramid with three side faces 212, 214, 216
Angled at 5 degrees, the side-view images from the fish-eye lens inner lens groups 202b, 204b, 206b are separated into three separate camera lenses 222, 224, 226.
These camera lenses focus the image on a CCD array in the camera's image plane.
This embodiment also has an end view fisheye lens, the inner lens group of which is shown as 200b. The end view image passes from the bottom to the top via the prism 210 and is moved by the fourth camera lens 220 to C
It is focused on a CD array.

In this configuration, three side images are located on the CCD array at the three corners of the triangle,
The edge image is located at the center of the triangle. A more efficient use of the area of the CCD array is to place these four images at the corners of a triangle, which can be achieved by using a rotating prism or fiber optics.

In both the fisheye embodiments of FIGS. 6 and 9, distortion can be removed by the computer software Code V. Code V was used in this application example, but other commercially available software programs can also be used.

The video image obtained by the CCD camera 34 (FIG. 2) or 134 (FIG. 6) can be transmitted to the ground surface at a rate of about 30 frames per second via an optical fiber cable. However, for compatibility with other downhole and surface equipment, it is desirable to use standard copper wireline cables. Such a standard wireline cable does not have the required bandwidth, so the video signal is compressed, for example, in the data processing block 58 of FIG. Several video compression techniques are known. One such technology is JPEG, which is often
Used in video compression for computer displays. For example, Jerome M. Shapiro
"Embedded Image Coding Using Zero Tree of Wavelet Coefficients (Embedded Image C
Odging Use Zerotrees of
Wavelet Coefficients) ", IE
EE Transactions on Signal Processing, Vol. 41, no. 12, 1993 12
Moon, or Amir Said and William A.
Pearlman "A new fast and efficient image codec based on configuration partitioning in a hierarchical tree (AN
ew, Fast, and Efficient I
mage Codec Based on Set P
artitioning in Hierarchic
al Trees) ", IEEE Transactions on Circuits and Systems for Video Technology, Vol. 6, no. 3, wavelet as described in June 1966
t) Compression techniques are preferred. Other compression techniques can be used. Video compression techniques degrade the signal somewhat and may also need to transmit a signal with reduced resolution or lower frame rate. Such a compromise is acceptable in production well logging.

Although the specific embodiments of the present invention have been described in detail above, the present invention should not be limited to only these specific examples, but may be variously modified without departing from the technical scope of the present invention. Of course is possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state in which a video logging device according to the present invention is disposed in a wellbore.

FIG. 2 is a schematic partial cross-sectional view of an optical module of the apparatus of FIG.

FIG. 3 is a schematic diagram showing the combined end and side views provided by the apparatus of FIG. 1 before correcting for distortion in the side views.

FIG. 4 is a schematic diagram showing an end view and a side view after converting the side view into linear coordinates in order to remove distortion.

FIG. 5 is a graph showing a distortion correction curve used to go from FIG. 3 to FIG. 4;

FIG. 6 is a schematic view showing another embodiment of the present invention.

FIG. 7 is a schematic diagram showing an optical prism used in the embodiment of FIG.

FIG. 8 is a schematic diagram showing a CCD array map for the embodiment of FIG.

FIG. 9 is a schematic sectional view showing another embodiment of the present invention.

FIG. 10 is a schematic diagram showing an optical prism used in the embodiment of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Video well logging device 12 Well (bore hole) 20 Surface equipment 22 Casing 28 Lower optical module 30 Control module 32 Telemetry module 34 CCD camera 36 CCD array 40 Optical group 42 Optical block 44 Edge view optical system 50 , 52, 54 LED

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Robert Jay. Schroeder United States, Connecticut 06470, Newtown, Castle Hill Road 71 (72) Inventor Benowa Que United States, Connecticut 06804, Bethel, Kellogg Street 11 (72) Inventor Jeffrey A. Turban United States, Connecticut 06804, Brookfield, Fountain Ridge 18

Claims (28)

[Claims] 1. A video inspection device for inspecting the inside of a well or pipeline, wherein the housing has an end and a side and is adapted to be moved through the well or pipeline. A camera mounted in the housing, an edge illuminator adapted to illuminate the outer edge zone, a side illuminator adapted to illuminate the outer edge zone, observing the exterior in the edge zone An end window for transmitting light from the end zone to the camera via the end window; and an end window for transmitting light from the end zone to the camera. A side optic for transmitting light to the camera through a side window. 2. Apparatus according to claim 1, wherein the camera has a common image plane for the end view and the side view. 3. Apparatus according to claim 2, wherein said camera comprises a CCD camera having a CCD in its image plane. 4. The apparatus of claim 1, wherein the side window has a transparent block. 5. The side optical system according to claim 4, wherein:
An apparatus having a concave surface in the block, the concave surface facing an end of the housing and a mirror coated. 6. The apparatus according to claim 5, wherein said end optics has an aperture in said mirror integral with said block. 7. The optical system according to claim 6, wherein the end optical system and the side optical system have at least some optical elements, and the common optical element is disposed in front of the block and the camera. An apparatus comprising a camera lens group. 8. The apparatus according to claim 1, wherein the edge optics and the side optics have at least some common optical elements. 9. The camera of claim 8, wherein the common optical element has a camera lens group disposed in front of the camera, wherein the lens group has a direction in which light propagates toward the camera. An apparatus comprising a biconcave lens, a plano-convex lens, and a doublet. 10. The method according to claim 4, wherein the end optical system has a first concave / convex meniscus lens, a second concave / convex meniscus lens, and the block in a light propagation direction toward the camera. Characteristic device. 11. The apparatus according to claim 10, wherein the first concave / convex meniscus lens has the end window and is pressure-resistant. 12. The apparatus according to claim 1, wherein said edge lighting means comprises a plurality of light emitting diodes. 13. The apparatus according to claim 12, wherein the light emitting diodes are arranged around the end window and are directed toward a side zone. 14. The apparatus according to claim 1, wherein said side lighting means comprises a plurality of light emitting diodes. 15. The apparatus of claim 14, wherein the light emitting diodes are disposed adjacent to the side window and are directed to a side zone. 16. The apparatus of claim 4 wherein said side illuminating means includes a plurality of LEDs disposed circumferentially around said housing above said block and a housing below said block. An apparatus comprising a plurality of LEDs disposed circumferentially therearound. 17. The apparatus according to claim 12, wherein the LED emits light in a near infrared region. 18. The device according to claim 1, wherein each of the edge illuminating means and the side illuminating means has a plurality of LEDs for turning on and off the LEDs to save power. Apparatus characterized in that means are provided. 19. The apparatus according to claim 18, further comprising means for turning on and off the camera in synchronization with the LED. 20. The apparatus of claim 1, wherein at least one of said windows comprises sapphire. 21. The apparatus of claim 1, wherein at least one of the windows has a sapphire coating on an outer surface thereof. 22. The method of claim 1, further comprising data compression means for compressing the image taken by the camera, and telemetry means for transmitting the compressed image to the ground. Equipment to do. 23. The apparatus according to claim 22, wherein said telemetry means comprises an electrical cable comprising a metal conductor. 24. The apparatus according to claim 5, wherein means are provided for the mirror to distort the side view image and to remap the skewed image to linear coordinates. 25. A video inspection or logging device, comprising: a housing, a camera mounted in the housing and having an image surface, mounted in the housing, from a side of the housing toward the camera. An optical block having a concave surface coated with a mirror for reflecting light, wherein the optical block is disposed between the block and the camera and focuses light reflected from the mirror onto an image plane of the camera. A camera lens group to be illuminated; side illuminating means disposed in the housing for illuminating a lateral zone outside the optical block. 26. The apparatus according to claim 25, wherein said illuminating means includes a plurality of LEDs that emit infrared light. 27. The image from each fish-eye lens according to claim 1, wherein the side optical system has a plurality of fish-eye lenses for transmitting a side image into the housing, and is provided inside the housing. A prism means for separately directing the camera to the camera. 28. The method of claim 27, wherein the optical system includes a fisheye lens for transmitting an edge image into the housing, and wherein the prism directs the edge image separately to the camera. And equipment.