Patent Application
20190300325
The present disclosure relates to the field of groundwater monitoring, and in particular to a mechanism for determining accurate cable draw and return.
Wells are drilled into the earth for a variety of reasons. The ability to effectively and efficiently monitor a wellbore, for example to assess water levels depends on an accurate determination of depth. A variety of instruments are available for water monitoring, but the assessment of depth has its challenges, in particular with portable well monitoring equipment.
Methods to determine well depth are known, and generally include a calibrated sensor configured to mechanically or optically engage the cable. Upon deployment or retrieval of the cable, the sensor engages the cable and provides the operator with an assessment of cable draw. These systems are effective, but can be very sensitive to contamination from the downhole and surrounding environment.
In addition to making an accurate determination of cable draw, portable well monitoring equipment must also be able to manage the length of cable being used. Where there is considerable cable being deployed and retrieved, the level distribution of the cable upon the cable reel, in particular during retrieval can become a major challenge.
Technologies are known to facilitate the wrapping of line (i.e. rope, piping, etc.) upon a receiving reel during a retrieval operation. These ‘level-wind’ systems provide a coordinated winding of the line, but require a reciprocating guide that positions the cable in a defined winding pattern. This reciprocating movement can be problematic, however, to sensors associated therewith.
There is clearly a need for a downhole monitoring system that permits for an accurate determination of cable draw, while also enabling a level distribution of cable upon the cable reel.
According to an aspect of an embodiment, provided is a downhole depth measuring apparatus. The downhole depth measuring apparatus comprises a frame, a cable reel rotatably supported upon the frame, a length of cable carried upon the cable reel, and a level wind assembly supported on the frame for level distribution of the cable on the cable reel during retrieval of the cable. The level wind assembly is operably coupled to a stationary counter assembly.
The foregoing and other features and advantages will be apparent from the following description of the disclosure as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the disclosure and to enable a person skilled in the pertinent art to make and use the disclosure. The drawings are not to scale.
Specific embodiments of the present disclosure are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following
Referring now to
Having regard to
Referring now to the various views of apparatus 10 shown in
The level wind assembly 26 is supported upon the frame 20 by a support bracket 50. The support bracket 50 extends outwardly of the frame 20, to permit the cable 24 to drop vertically into the downhole environment. The support bracket 50 may be a separately formed element fixedly attached to the reel support portion 40 of the frame 20, or may be integrally formed with the reel support portion 40 and/or the frame 20.
Referring now to
Rotatably mounted between the support bracket 50 and the winder plate 54 is a shaft 58. The shaft 58 includes a set of reversely extending spiral grooves 60, a configuration generally known in the art as a self reversing screw shaft or a diamond lead screw. A first end 62 of the shaft 58 is supported at the support bracket 50 by a first support member 64, while a second end 66 of the shaft 58 is supported at the winder plate 54 by a second support member 68. As shown, the shaft 58 is configured for rotation about an axis parallel to the axis of rotation A. To reduce friction and improve rotational performance, suitable bushings and/or bearings may be used to rotatably mount the first and second ends 62, 66 of the shaft 58 at the respective first and second support members 64, 68. The first and second support members 64, 68 are attached to the respective support bracket 50 and winder plate 54 using a suitable fastener (i.e. threaded fastener) and/or adhesive. In some embodiments, the first and second support members 64, 68 may be integrally formed with the respective support bracket 50 and winder plate 54.
On at least one side, shaft 58 is provided with a shaft sprocket 70 which is rotationally fixed relative to the shaft 58 such that rotation of the shaft sprocket 70 causes corresponding rotation of the shaft 58. In the embodiment shown, the shaft 58 and the shaft sprocket 70 present corresponding keyed surfaces 72a and 72b, respectively, to ensure a rotationally fixed relationship. The shaft sprocket 70 additionally cooperates with a first spacer 74 and a second spacer 76, and at least one registration peg 78 that spans therebetween. The at least one registration peg 78 extends through an aperture in the shaft sprocket 70, and is pressfit into receiving apertures provided in each of the first and second spacers 74, 76, therein ensuring fixed relative rotation of the first and second spacers 74, 76 with the shaft sprocket 70. The arrangement may also include a chain guard 80. As shown, the shaft sprocket 70 is located proximal the first end 62 of the shaft 58.
Similarly, the cable reel 22 is provided with a reel sprocket 82. The reel sprocket 82 and the cable reel 22 are coaxial relative to the spindle 42, the reel sprocket 82 being rotationally fixed relative to the cable reel 22 such that rotation of the cable reel 22 causes corresponding rotation of the reel sprocket 82. The reel sprocket 82 is operatively connected to the shaft sprocket 70 using a suitable endless belt member 84. As such, the cable reel 22 is rotationally linked to the shaft 58. Accordingly, rotation of the cable reel 22 imparts a torque upon the shaft 58 through the intermediate driving action of the endless belt member 84 between the reel sprocket 82 and the shaft sprocket 70. In the embodiment shown, the endless belt member 84 is presented in the form of a chain.
Slideably mounted upon the cross-rods 52 is a cable count assembly 86. With reference now to
The cable count assembly 86 is mounted upon the cross-rods 52 in a manner that permits reversible lateral movement of the cable count assembly 86 between a first position proximal the support bracket 50 and a second position proximal the winder plate 54. As shown, each of the first and second plates 88, 90 is configured with a plurality of cooperating apertures 96 that align and permit the cable count assembly 86 to slidingly move upon the cross-rods 52. To facilitate smooth lateral movement, a slide element 98a, 98b, 98c, 98d (collectively slide elements 98) is provided between the first and second plates 88, 90 at each location of the cooperating apertures 96. The slide elements 98 may be provided in the form of a suitable linear bearing or bushing.
The cable count assembly 86 further includes a shaft aperture 100 in each of the first and second plates 88, 90 that align to the shaft 58 and permit the cable count assembly 86 to laterally move relative thereto. The apertures 100 in each of the first and second plates 88, 90 are sized with a diameter that is slightly larger than the outside diameter of the shaft 58, to avoid direct contact therebetween during lateral movement of the cable count assembly 86 upon the cross-rods 52.
Between the first and second plates 88, 90 there is located, proximal the shaft 58, a follower 102 (see
Upon rotation of the shaft 58, for example during a cable retrieval operation, the follower 102 fixedly attached between the first and second plates 88, 90 causes lateral movement of the cable count assembly 86 on the cross-rods 52 from one side of the level wind assembly 26 to the other and back. The cable reel 22 is operably connected to the shaft 58 such that the shaft 58 is rotationally linked to the cable reel 22. Accordingly, rotation of the cable reel 22 translates into back and forth (i.e. reciprocating) lateral movement of the level wind assembly 26 upon the cross-rods 52 between the first position proximal the support bracket 50 and the second position proximal the winder plate 54. With this motion of the level wind assembly 26, during a retrieval operation, the cable 24 is directed in a controlled manner along substantially the entire width of the cable reel 22 generally perpendicular to its axis of rotation A.
As mentioned previously, the gap-spacing established between the first and second plates 88, 90 permits for the cable count wheel 94 to be rotatably mounted therebetween. As shown in
The cable count wheel 94 is mounted upon the rail 112 in a manner that permits for a fixed relative rotation of the wheel 94 relative to the rail 112, yet permits the cable count wheel 94 to displace laterally along the rail 112 as the cable count assembly 86 moves laterally upon the cross-rods 52 between the first position proximal the support bracket 50 and the second position proximal the winder plate 54.
The cable count wheel 94 includes a first wheel flange 122, a second wheel flange 124 and a cable engagement portion situated therebetween. The first and second wheel flanges 122, 124 and the cable engagement portion are positioned coaxially relative to the axis of rotation of the rail 112. The cable engagement portion is configured with a reduced diameter compared to the first and second wheel flanges 122, 124, thus presenting a groove 126 that receives and engages the cable 24 during use. In some embodiments, the first and second wheel flanges 122, 124 may be configured to present a cable engagement portion that is a v-groove, to direct the cable 24 to the center thereof.
The rail 112 is configured with at least one planar bearing surface which extends along at least a portion of the length of the rail 112 and which cooperates with a slide element (i.e. a bearing) provided on the cable count wheel 94. With reference to
The cable count assembly 86 may additionally include a cable guide presenting a first roller 140a and a second roller 140b. The first and second rollers 140a, 140b are mounted on respective guide rods 142a, 142b mounted between respective guide supports 144a, 144b. The guide supports 144a, 144b each present a tab 146 on each side thereof, which cooperate with a corresponding slot 148 on each of the first and second plates 88, 90. The first and second rollers 140a, 140b are arranged with a gap-spacing therebetween, permitting guided passage of the cable 24 between the cable count wheel 94 and the cable reel 22.
Engagement of the cable 24 within the groove 126 of the cable count wheel 94 serves to rotate the cable count wheel 94 during deployment and retrieval of the cable 24 relative to the cable reel 22. In turn, the engagement of the bearings 132 upon the respective bearing surfaces 130 of the rail 112 serve to transfer the rotation of the cable count wheel 94 to the rail 112.
Rotation of the cable count wheel 94 is dependent upon the engagement and movement of the cable 24 relative thereto. Stated differently, the rotation of the cable count wheel 94 is operably decoupled from the cable reel 22. Although the cable count wheel 94 is mounted on the cable count assembly 86 which moves laterally within the level wind assembly 26, the rotation of the cable count wheel 94 is dependent upon the engagement of the cable count wheel 94 with the cable 24, and not through a direct linkage (i.e. geared) with the cable reel 22.
As mentioned above, the first end 114 of the rail 112 extends towards and through the support bracket 50, and into the counter assembly 120 mounted on the support bracket 50 of the frame 20. With this arrangement, the counter assembly 120 is kept stationary relative to the frame 20, that is it does not move with the level wind assembly during deployment/retrieval of the cable 24. It will be appreciated that a variety of counter assemblies may be suitable used. In the embodiment shown, the counter assembly 120 is provided in the form of a rotary encoder. The rotary encoder is operably connected to the rail 112. As generally known in the art, rotary encoders are used to convert rotational motion of a shaft or axle into an analog or digital signal that may be indicative of a number of parameters, including the angular position of the rail 112. With a calibration of the encoder having regard to the dimension/circumference of the cable count wheel 94, and with a count of the number of rotations of the rail 112 from an initial reference point, an accurate determination can be made of the length of cable 24 deployed and/or retrieved onto the cable reel 22. A variety of rotary encoders may be used for this application including, but not limited to, a mechanical rotary encoder, a magnetic rotary encoder, and an optical rotary encoder.
In the embodiment shown in
The clear sections 154 (or slits 158) cooperate with a light source 160 and an optical sensor 162, arranged on opposite side of the disk 152. The light source 160 and optical sensor 162 are situated relative to the disk such that the incident light is detected by the optical sensor 162 when the incident light passes through the clear sections 154 (or slits 158). Readings from the optical sensor 162 are analyzed via suitable circuitry (i.e. a processor, not shown), and the resulting output is used to determine positional information for the rail 112. With knowledge of the rotational turn count of the rail 112, combined with the known dimensions of the cable count wheel 94, an accurate determination of the length of cable deployed from an initial reference point can be calculated.
While various embodiments have been described above, it should be understood that they have been presented only as illustrations and examples of the present disclosure, and not by way of limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the disclosure. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the appended claims and their equivalents. It will also be understood that each feature of each embodiment discussed herein, and of each reference cited herein, can be used in combination with the features of any other embodiment. All patents and publications discussed herein are incorporated by reference herein in their entirety.
This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/431,503 filed Dec. 8, 2016, the contents of which are incorporated herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2017/051485 | 12/7/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62431503 | Dec 2016 | US |
