DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an embodiment of the invention;
FIG. 2 is a front view of the cylindrical downhole camera comprising the embodiment of FIG. 1;
FIGS. 3a and 3b are front and side views, respectively, illustrating the tilting characteristics of the downhole camera assembly of FIG. 2;
FIG. 4 is a perspective view illustrating the downhole viewing coverage obtained by tilting the camera of FIG. 2;
FIG. 5 is a perspective view illustrating the semi-spherical field of view of the downhole imaging tool of the invention obtained by both tilting and rotating the camera's antenna;
FIG. 6 is a block diagram illustrating the functional operation of the camera of FIG. 2;
FIG. 7 is a block diagram illustrating the functional operation of the overall downhole tool comprising the embodiment of FIG. 1;
FIG. 8 is a perspective view illustrating the downhole imaging tool of FIG. 1 used to detect and inspect damaged or stuck tools in a downhole well casing;
FIG. 9 is a perspective view illustrating the downhole imaging tool of FIG. 1 used to detect and inspect slots, slits, frac holes, cracks, pipe collars, protrusions and other obstructions in a downhole well casing;
FIG. 10 is a perspective view illustrating the downhole imaging tool of FIG. 1 used to detect and inspect stuck pipes, tools, and other structures in a downhole open well bore; and
FIG. 11 is a block diagram of the above ground equipment for the downhole inspection system of FIG. 1.
DETAILED DESCRIPTION Referring to the drawings, and particularly to FIGS. 1-11, an embodiment of a downhole imaging tool and its method of use incorporating the invention is shown and generally designated by the reference numeral 10.
In FIG. 1, a new and improved downhole inspection tool 10 comprising an embodiment of the invention. The downhole inspection tool 10 is self contained and is comprised of a downhole camera assembly 18, an antenna 20, a data and control electronics assembly and memory 16, a downhole tool power supply 14, a backup battery module 15, and a downhole centralizing unit 12. The downhole camera assembly 18 may utilize millimeter wave imaging technology, typically operating in the frequency range from about 20 to about 300 GHz, however the tool is likewise capable of utilizing other imaging technologies including but not limited to of RF devices, microwave devices, infra-red devices, ultrasonic devices, acoustical devices, and optical devices. An appropriate antenna 20 is incorporated on the bottom end of the camera assembly 18 for directing the imaging source downward in a well bore onto a subject and for receiving images reflected therefrom. A data and control electronics assembly 16 is comprised of a microcontroller and a memory for storing programs, image data, and tool status data. The electronics assembly 16 further comprises means for two-way communication to above ground equipment via either wire or fiber optics or both. A downhole power supply 14, which receives electric current at between about 200 volts and about 600 volts from an above ground AC or DC source, is used to develop required tool operating voltages ranging from between about plus and about minus 5 to 40 volts for use in powering the downhole tool. Optionally, the tool further comprises a backup battery module 15 as a secondary means of powering the camera and additional tool functions. The downhole inspection tool 10 is further comprised of a means for stabilizing itself inside a well tubing or casing through the utilization of devices comprised of one or more centralizing unit(s) 12, and/or stabilizer locking feet. Finally, the downhole imaging tool further comprises a temperature sensor, a pressure sensor, a pressure safety relief valve, and other sensors as required.
The downhole inspection tool 10 is used for various inspection functions in a well bore. Such inspections include, but are not limited to locating other downhole tools that may be stuck or otherwise impaired, observing how best to loosen and retrieve, stuck or impaired tools, and assisting in attaching other retrieval devices to stuck or impaired tools for removal from the well bore. The downhole inspection tool is further useful in locating other areas of interest in a well bore, such as, locating frac holes in well casings, slots in well casings, cracks or fractures in casings or tubing, obstructions in casings or tubing, and protruding structures inside casings or tubing.
FIG. 2 is a more detailed description of the downhole camera assembly 18 of FIG. 1. The camera assembly 18 houses the imaging module 26, which includes the high frequency millimeter wave or other imaging components and associated electronics. A rotation motor 22, located near the top of the camera assembly 18, has a rotating shaft 24 extending from the bottom end and attaching to the top portion of the imaging module 26. The rotating shaft 24 is limited to rotating the imaging module 26 in azimuth through 360 degrees in steps as small as 0.8 degrees or multiples thereof. Furthermore, an antenna tilting device 28 is attached between the bottom end of the imaging module 26 and the antenna 20 and is used to tilt the antenna through 180 degrees in elevation.
FIGS. 3a and 3b illustrate one configuration of the tilting device 28 for the camera assembly's antenna 20. The tilting device 28 rotates a pin 32, which is attached to a rotating antenna mounting plate 30, so that when the pin 32 rotates the antenna 20 rotates through a 180 degree arc. In another embodiment a servo controlled swivel rotates the antenna 20 through a 180 degree arc.
FIG. 4 illustrates tilting the camera antenna 20 over a 180 degree arc to illuminate a circular field of interest 36. The camera antenna 20 is shown positioned at 0 degrees 35 looking directly into the wall of a well casing 34, at 90 degrees 36 straight down the well bore casing, and at 135 degrees 37, respectively.
FIG. 5 illustrates the semi-hemispherical field of view 38 capability of the inspection tool 10 which is achieved by coupling the 360 degree rotation of the imaging module 26 with the 180 degree tilting characteristics of the tilting device 28. The combination of rotating the imaging module 26, which has the tilting device 28 and the antenna 20 attached at the bottom end thereof, through up to 360 degrees and tilting the antenna using the tilting device 28 through an angle up to 180 degrees allows the antenna to be focused 40 at any desired location within a hemispherical field of view 38. In another embodiment the antenna is positioned by a servo controlled swivel.
FIG. 6 is block diagram for the milli-meter wave camera assembly 18 utilized in the downhole inspection tool 10 which, in one embodiment of the invention operates in the frequency range of between about 20 and about 300 GHz. The basic components of the camera assembly 18 comprise a voltage controlled oscillator 42 coupled to a pre-amplifier 43, which drives the input of feedback control circuitry 44. The output of the feedback control circuitry 44 connects both to the antenna 20 and a low noise amplifier 45, which couples to a signal output takeoff 46 and back into the feedback circuit 44. A low noise intermediate frequency (IF) output signal is then taken from the output takeoff 46.
FIG. 7 is a block diagram illustrating the functional operation of a downhole inspection tool comprising an embodiment of the invention. A microcontroller unit (MCU) 50, which communicates with an above ground control console by means of a transceiver 49 and tool interface 48, provides master control of a downhole inspection tool comprising an embodiment of the invention. The MCU 50 controls the camera controller 54, the data acquisition unit 58, the imaging and control data memory bank 60, the motor controller 52, and antenna position controller 56 of the downhole inspection tool. The MCU 50 also tracks and communicates tool status to an above ground control console by means of the transceiver 49.
FIG. 8 is a perspective view illustrating an embodiment of the downhole inspection tool 10 used to detect and inspect damaged or stuck tools in a downhole well casing. The camera of the downhole inspection tool 10 focuses the circular field-of-view 36 from the antenna 20 on a broken drill bit 62 that is lodged sideways in a well casing 34. The picture from the camera assembles of the downhole inspection tool is displayed on an above ground computer monitor for viewing by personnel of the tool retrieval crew to aid in more efficiently removing the broken drill bit.
FIG. 9 is a perspective view illustrating an embodiment of the downhole inspection tool 10 used to inspect the conditions in a well bore casing 34. This illustrates the use of the tool for locating and inspecting such features as casing slots 64 and smaller slits 66, casing frac holes 68, casing cracks 70, casing pipe joint collars 72, casing wall protrusions 74, and other unwanted obstructions within a downhole well bore. In FIG. 9 the camera's antenna 20 is shown focused at 0 degrees 35 on a slot 64 in a well casing 34.
FIG. 10 is a perspective view illustrating an embodiment of the downhole inspection tool 10 used to inspect the conditions in an open well bore 76. This illustrates the use of the tool in which the tool's antenna 20 is focused 36 on a broken pipe 78 being lodge crosswise in an open well bore, thereby blocking access to the well bore for other tools and/or equipment to be placed therein.
FIG. 11 is a block diagram of the above ground equipment control console for operating embodiments of the downhole inspection tool 10. The above ground equipment control console is comprised of a controller 80 and computer/display 82 for controlling the overall operation of the system and displaying operational, status, and image data, a memory bank 84 for storing system and image information, an image processor 86 for processing image data, a transmitter/receiver (transceiver) 88 for communicating through a slip-ring interface 92 and downhole cable 94, and a power supply 90 for supplying power to both the downhole tool power supply 14 and above ground equipment.
Embodiments of the downhole inspection tool 10 can be operated in either wireline or slickline modes of operation. In the slickline mode there is no electrical connection with above ground equipment. In this mode the system operates from onboard battery power and stores image and status data in an onboard data storage memory bank. In this mode of operation, the tool is automatically turned on by onboard means, such as a timer, pressure sensor, or temperature sensor and takes downhole pictures based on a stored onboard operational program. The image data is then stored in the onboard data storage memory bank for above ground viewing later.
Various embodiments of a downhole inspection tool and method have been described in detail herein. It will be appreciated, however, that the invention provides applicable inventive concepts that can be embodied in a wide variety of contexts. For example, while the description has included embodiments of the tool used in downhole oil and gas well applications, it can provide inspective functions in many other applications and especially so where high pressure and/or high temperature environments are involved.
Although the invention has been described with reference to an illustrative embodiment, the foregoing description is not intended to limit the scope of the invention. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims incorporate any such modifications or embodiments.
