Key information

Title
Method and system for determining depth of a downhole survey instrument
Application number
20230392
Case type
National
Status
03.02.2025 Patent meddelt (B1)
Filed
11.04.2023
Effective date
11.04.2023
Publicly available
14.10.2024
Next annual fee due
30.04.2027
Applicant
Devico AS (NO)
Owner
Devico AS (NO)
Inventor
John Flåm (NO) et al.
Agent
ACAPO ONSAGERS AS (NO)
Granted
03.02.2025
Patent number
348477
Expiry date
11.04.2043

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
Method and system (100) for distance measurement of an item (340) or surface (500) based on the use of at least one rotating distance measurement assembly (110) arranged in engagement with the item (340) or surface (500), the rotating distance measurement assembly (110) being formed by a rotation member (120) and at least one inertial sensor (210, 220, 230) or sensor assembly (200) arranged to or into the rotation member (120) measuring accelerations of the rotation member (120), enabling calculation of the distance based on the measured accelerations and outer circumference of the rotation member (120).

Publications

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Documents

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Date
 Date Doc. No. Process Case number In/Out Journal description To/from
 02.03.2025 14-01 Saksbehandling 20230392(348477) UT PT Varsel om betaling av første årsavgift (3317) (PT20230392) CURO AS
 07.02.2025 13-01 Saksbehandling 20230392(348477) UT PT Registreringsbrev nasjonal patent (15) (PT20230392)
20.12.2024 12-01 Saksbehandling 20230392 INN Korrespondanse (Hovedbrev inn) CURO AS
 20.12.2024 11-01 Saksbehandling 20230392 UT Intention to grant CURO AS
 22.03.2024 10-05 Saksbehandling 20230392 INN NO20230392-trykningsklar-tekst_clean CURO AS
 22.03.2024 10-04 Saksbehandling 20230392 INN NO20230392-trykningsklar-tekst_annotated CURO AS
 22.03.2024 10-03 Saksbehandling 20230392 INN NO20230392-reply_office_action CURO AS
 22.03.2024 10-02 Saksbehandling 20230392 INN NO20230392-norske_krav CURO AS
 22.03.2024 10-01 Saksbehandling 20230392 INN Korrespondanse (Hovedbrev inn) CURO AS
 28.02.2024 09-01 Saksbehandling 20230392 UT Substantive examination CURO AS
 26.02.2024 08-01 Saksbehandling 20230392 INN Korrespondanse (Hovedbrev inn) CURO AS
 07.11.2023 07-04 Saksbehandling 20230392 INN NO20230392-Reply_Office_Action CURO AS
 07.11.2023 07-03 Saksbehandling 20230392 INN NO20230392-amended_specification_clean CURO AS
 07.11.2023 07-02 Saksbehandling 20230392 INN NO20230392-amended_specification_annotated CURO AS
 07.11.2023 07-01 Saksbehandling 20230392 INN Korrespondanse (Hovedbrev inn) CURO AS
 07.08.2023 06-02 Saksbehandling 20230392 UT PT report 10:44:31
07.08.2023 06-01 Saksbehandling 20230392 UT Substantive examination CURO AS
 03.05.2023 05-03 Saksbehandling 20230392 INN 20230392_POA CURO AS
 03.05.2023 05-02 Saksbehandling 20230392 INN 20230392_assignment CURO AS
 03.05.2023 05-01 Saksbehandling 20230392 INN Korrespondanse (Hovedbrev inn) CURO AS
 27.04.2023 04-01 Saksbehandling 20230392 INN Korrespondanse (Hovedbrev inn) CURO AS
 12.04.2023 03-01 Saksbehandling 20230392 UT Formal Examination 1 CURO AS
 12.04.2023 02-01 Saksbehandling 20230392 UT Infobrev til oppfinner CURO AS
 11.04.2023 01-03 Saksbehandling 20230392 INN U4419-text CURO AS
 11.04.2023 01-02 Saksbehandling 20230392 INN U4419-figures CURO AS
 11.04.2023 01-01 Saksbehandling 20230392 INN Søknadsskjema Patent CURO AS

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
Method and system for distance measurement of an item or surfaceThe present invention is related to a method for distance measurement of an item or surface, according to the preamble of claim 1.The present invention is also related to a system for distance measurement of an item or surface, according to the preamble of claim 10.The present invention is especially related to the use of at least one rotating distance measurement assembly in engagement with the item or surface, wherein at least one sensor or sensor assembly is arranged to or within a rotation member and rotates with the rotation member.BackgroundDistance measurements can be performed by a variety of methods, whereas the use of wheels is common. The wheel is either rolled along the surface where the distance is to be measured, or the item to be measured is pulled along the outer surface of the wheel. Examples of the latter may include measuring the distance of a section of cable, rope, wire, and so forth. In, e.g., the drilling and borehole surveying industry wheel systems are utilized to measure the length of wireline lowered or pulled out of a drill string or borehole.When a wheel is used to measure distance, it typically interfaces with an encoder that counts the number of rotations the wheel is subjected to. Combining this with the known circumference of the wheel itself, allows for measuring the distance. An encoder is a position sensor that determines angular position, or change in angular position, of a rotating shaft. Multiple types exist and may use mechanical, optical and magnetic solutions to detect the rotation of the shaft. In high speed and high accuracy application the optical encoders are most common. These will typically rely on a coded disc that rotates with the shaft and a stationary light source and light sensor that counts or detects the codes on the disc.There are multiple practical drawbacks with encoders, particularly in rough applications like wire counters as found in the drilling industry. The encoders typically have the shaft integrated, meaning the wheel axle must interface with the shaft. Vibrations, shocks, radial forces, temperature changes and general degradation may over time weaken the mounting and cause the wheel to spin more or less than the shaft thereby rendering the distance measurements inaccurate. This further makes the encoder and measuring system more difficult to repair and replace. Encoders further incorporates fine mechanics with rotating and non-rotating components, making them sensitive to dust, debris, and water. Due to the moving parts, it can be difficult to properly protect an encoder and it may significantly increase the price of the system.Encoders are often relatively power-hungry devices. Hence, a spacious battery solution, or external power supply must also be a part of the measurement system.Encoders may also be bulky by themselves, and with the axle mount, the system will often need to be designed around the encoder and thereby prevent achieving a design that is be optimized for the actual use of the system.There is accordingly a need for a method and system for distance measurement of an item or surface removing the requirement of the use of an encoder.ObjectThe main object of the present invention is to provide a distance measurement method and system for distance measurement of an item or surface partly or entirely solving the problems and lacks of prior art discussed above.An object of the present invention is to provide a method and system for distance measurement of an item or surface removing the requirement of an encoder.An object of the present invention is to provide a method and system for distance measurement of an item or surface avoiding the need for arrangement of distance measurement sensor(s) in connection with or to an axle of the rotation member.It is an object of the present invention to provide a method and system for distance measurement of an item or surface using at least one rotating distance measurement assembly formed by a rotation member and at least one inertial sensor or sensor assembly arranged thereto or embedded therein.A further object of the present invention is to provide a system for distance measurement of an item or surface providing detachable arrangement of the at least one sensor or sensor assembly to the rotating member enabling service or replacement at any time, without the need for replacing other parts. It is an object of the present invention to provide a system for distance measurement of an item or surface that is easy to protect from dirt and water.An object of the present invention is to provide a method and system for distance measurement of an item or surface that does not rely on additional rotating or non-rotating components.It is further an object of the present invention to provide a method and system for distance measurement of an item or surface capable of handling challenging conditions with vibrations, shocks and high radial forces present in many application areas.A further object of the present invention is to provide a method and system for distance measurement of an item or surface involving lower costs both for production, installation and maintenance, compared to prior art solutions.An object of the present invention is to provide a method and system for distance measurement of an item or surface having lower power consumption/requirements than prior art solutions.It is an object of the present invention to provide a method and system for distance measurement of an item or surface not requiring redesign or modifications of items or surfaces that are to be distance measured.An object of the present invention is to provide a method and system for distance measurement of an item or surface applicable for distance measurements of various areas, both items and surfaces. It is an object of the present invention to provide a method and system for distance measurement of an item or surface able to accurately measure the distance over a longer operational life compared to prior art solutions.Further objects will appear from the following description, claims and attached drawings. The inventionA method for distance measurement of an item or surface according to the present invention is defined by the technical features of claim 1. Preferable features of the method are described in the dependent method claims.A system for distance measurement of an item or surface according to the present invention is defined by the technical features of claim 10. Preferable features of the system are described in the dependent system claims.The measurement principle of the method and system according to the present invention is based on the use of at least one rotating distance measurement assembly arranged in engagement with an item or surface to be distance measured. In accordance with the present invention, the at least one rotating distance measurement assembly is formed by a rotation member and at least one inertial sensor or sensor assembly arranged thereto or embedded therein.The measurement principle of the method and system according to the present invention is based on measuring accelerations as the rotating distance measurement assembly (rotation member) is rotated and the calculation of distance based on the measured accelerations and outer circumference of the rotation member. The measurement of accelerations also enables derivation of angular rate or change.The method for distance measurement of an item or surface according to the present invention comprises arranging the at least one rotating distance measurement assembly in engagement with the item or surface to be distance measured.The method according to the present invention comprises applying rotation to the rotation member by movement of the rotation member along the item or surface or by movement of the item or surface applying rotation to the rotation member.According to the present invention, the method comprises, during the rotation of the rotation member, determining the angular change of the rotation member by using sensor data from the at least one inertial sensor or sensor assembly.The method according to the present invention further comprises calculating the distance of the item or surface based on determined angular change and outer circumference of the rotation member. In the terms of the present invention, the calculated distance can also be considered as the length of an item or surface.In accordance with one embodiment of the method according to the present invention, the method comprises determining angular change by using at least one accelerometer, at least one gyroscope, or a combination thereof, or an inertial measurement unit.According to a further embodiment of the method according to the present invention the method comprises determining angular change by measuring angular rate and/or change in acceleration. According to a further embodiment of the method according to the present invention, the method comprises using at least one gyroscope to detect angular rate and quantify change in speed and centripetal acceleration of the rotation member.In accordance with one embodiment of the method according to the present invention, the method comprises using sensor data from at least one gyroscope as direct input in the distance measurement calculation or to compensate sensor data from the at least one accelerometer. According to one embodiment of the present invention, the method comprises analysing the sine wave cycles of the acceleration measurements from the at least one sensor or sensor assembly to provide a measure of angular change of the rotation member.According to another embodiment of the present invention, the method comprises calculating angular change directly from the accelerometer output, or from a filtered or adjusted accelerometer output.In accordance with one embodiment of the present invention, the method comprises calculating distance of the item or surface by number of rotations of the rotation member x outer circumference of the rotation member.According to one embodiment of the method according to the present invention, the method comprises using the following formula for calculating the distance of the item or surface: π x radius of rotation member x angular change, where angular change is expressed in radians and include the number of revolutions.According to one embodiment of the method according to the present invention, the method comprises using the following formula for calculating the depth of a deployed downhole survey instrument in a drill hole, drill string or casing: Depth = π * radius of rotation member * angular change, where angular change is expressed in radians and include the number of revolutions. The system according to the present invention comprises at least one rotating distance measurement assembly arranged in engagement (contact) with an item or surface to be measured. The at least one rotating measurement assembly is formed by a rotation member and at least one inertial sensor or sensor assembly arranged into or onto the rotation member.In accordance with one embodiment of the present invention, the at least one inertial sensor or sensor assembly is detachably arranged into or onto the rotation member.According to the present invention, the at least one rotating distance measurement assembly will be in direct engagement/contact with the item or surface to be measured by the rotation member, but the measurement principle according to the present invention may also be utilized for applications where the rotation member is indirect engagement/contact with the item or surface to be measured.According to the present invention the at least one inertial sensor or sensor assembly comprises at least one accelerometer, or at least one gyroscope, or a combination, or an inertial measurement unit (IMU) containing both accelerometers and gyroscopes. The mentioned at least one inertial sensor or sensor assembly may further be configured for measuring angular rate or change in acceleration.The system according to the present invention further comprises a control unit configured, by comprising means and/or software, to retrieve sensor data from the at least one inertial sensor or sensor assembly and storage of data in an internal and/or external memory for internal or external processing of retrieved sensor data in real-time or for post processing (offline) of the stored/logged data.In accordance with a further embodiment of the control unit, the control unit is configured, by comprising means and/or software, to determine angular change from the measured angular rate and/or change in acceleration.The control unit is according to a further embodiment of the present invention provided with wired or wireless communication means or arranged to a communication module with wired or wireless communication means for communication with embedded or external units, such a user terminal. In accordance with the present invention, the system further comprises a user terminal enabling presentation of measurement information for a user. Examples of user terminals may include an embedded display or an external display, a computer or a handheld unit such as a smart phone, tablet or similar. The communication with user terminals in the form of external devices is preferably wireless.In accordance with the present invention, the components of the system may be mounted together into one unit or be separated into multiple units. The former is preferable to secure ease of overall use and assembly. The latter may in some cases be preferable in order to distribute weight and maintain rotation member balance during rotation. Communication between each component/unit may in such case be achieved via conducting cable or wirelessly.The rotation member according to the present invention is circular and is arranged to a support structure, stationary or movable, via a center axle. The rotation member is accordingly arranged freely rotating to the support structure by means of the center axle.According to the present invention, the at least one inertial sensor or sensor assembly is arranged to or embedded in the rotation member at any location at or between the rotation member center axle and outer circumference or surface thereof, for instance on a spoke.Arrangement of the at least one inertial sensor or sensor assembly closer to the center axle is preferable to reduce the centripetal acceleration and its effect on the at least one inertial sensor or sensor assembly.Besides from the arrangement of the at least one inertial sensor or sensor assembly to the rotation member, the at least one inertial sensor or sensor assembly is otherwise fully independent of the rotation member, such that the system is straightforward to unmount for replacement or repackaging.According to one embodiment of the present invention, the at least one inertial sensor or sensor assembly and other electronics are mounted in a dust and water/pressure proof housing, which may vary according to the requirements of the application in question.The independent nature of the system, where one simply arranges (attaches) at least one inertial sensor or sensor assembly to a rotation member, makes it independent from the application, and the same inertial sensor or sensor assembly and electronics may be utilized equally well in high temperature conditions or under water, as in any other application. Accordingly, the distance measurement is according to the present invention performed by that the at least rotating distance measurement assembly is arranged in engagement with an item or surface to be measured. In accordance with the present invention, rotation of the rotation member is affected by movement of the item or surface, or movement of the rotating distance measurement assembly in relation to the item or surface.E.g., if the item is a wire, cable, rope or similar, the rotation member is arranged in engagement with the item, such that, when the item is deployed or retrieved, this results in rotation of the rotation member. In another application, the item to be measured is laying on a surface and wherein the rotating distance measurement assembly is moved along the item resulting in rotation of the rotation member.In connection with distance measurement of a surface, the rotation member is arranged in engagement with the surface, and wherein the surface is moved resulting in rotation of the rotation member or wherein the rotating distance measurement assembly is moved in relation to the surface resulting in rotation of the rotation member.Accordingly, regardless of the application, the measuring principle is based on rotation of a rotation member and determining angular change based on measurements from at least one inertial sensor or sensor assembly arranged in a fixed position on the rotation member and as the rotation member rotates, the at least one inertial sensor or sensor assembly rotates correspondingly.As the rotation member is rotated, the at least one inertial sensor or sensor assembly will rotate at the same angular rate as the rotation member.During the measurement process, the at least one inertial sensor or sensor assembly continuously registers acceleration and/or angular rate data, that will be used to calculate the distance.In accordance with one embodiment of the present invention, the at least one inertial sensor or sensor assembly is at least one accelerometer. Rotating accelerometer(s) produce sensor data signals that resemble a sine wave around each axis. The number of cycles thus corresponds to the number of rotations of the rotation member.According to one embodiment of the present invention, the at least one inertial sensor or sensor assembly is at least one gyroscope. Rotating gyroscope(s) produce sensor data signals that are directly proportional to the rotation rate. In accordance with one embodiment of the present invention, the at least one inertial sensor assembly comprises at least one accelerometer and at least one gyroscope, or an IMU.The mentioned characteristics from the at least one inertial sensor or sensor assembly, digital signal processing and the known circumference of the rotation member form the basis for deriving the distance measurement according to the present invention.The sine wave characteristics from the at least one accelerometer will be affected by changes in rotation member/rotational speed. In a system where the rotation member is moving with a constant rotational velocity, the centripetal acceleration remains constant and the at least one accelerometer will output a repeating wave form. However, during the start, stop, while vibrating or at any other point where the rotation member speed changes, the centripetal acceleration also changes and affects the wave form output from the at least one accelerometer. A constant and very high speed may also cause similar effects if the centripetal acceleration nears the limits of the accelerometer. Similar issues occur if the centripetal acceleration becomes high for other reasons. In accordance with the present invention, by providing the at least one inertial sensor assembly with at least one gyroscope in addition to at least one accelerometer, the at least one gyroscope, during such periods, is utilized to detect and quantify the change in speed and centripetal acceleration. In accordance with one embodiment of the present invention, the control unit is configured, by comprising means and/or software, to use gyroscope sensor data either as direct input in the distance measurement calculation, or to compensate the accelerometer data. By correlating the angular rate measured by the gyroscope sensor with the time or duration of the measurement process a direct measure of the angular change is found. However, since gyroscope sensors typically are subject to drift the accuracy of the angular change may be affected when measuring over longer periods. For this reason, it is preferable to use gyroscopes in combination with accelerometers and use data from one to compensate the other. In its simplest form this may be done by replacing the angular change determined by the accelerometer with the angular change determined by the gyroscope, for instance to correct for short term rapid accelerations of the rotation member. Alternatively, or additionally, compensation may be performed by calculating centripetal acceleration from the gyroscope data (angular rate) and use this to adjust the accelerometer data accordingly. Such compensation requires the knowledge of the radial position of the accelerometer sensor(s) and is calculated from standard formulas for circular motion. Centripetal acceleration is proportional to radius (distance to inertial sensor) times angular rate squared. This latter form of compensation may be performed equally well in the opposite direction, or both directions, enabling usage of accelerometer data for compensation of gyroscope sensor drift.The method and system for distance measurement according to the present invention is applicable for a wide range of user applications, such as, but not limited to: Distance measuring roller wheels for construction, clamping to a bicycle wheel for measuring distance of a bicycle ride, clamping to pulleys or wheels for measuring distance of rope, chain, hoses, pipe, snake/tape, cable, wire, etc. The method and system for distance measurement is also applicable for different applications within the drilling industry. The method and system according to the present invention is applicable for determining depth of a downhole survey instrument, as used in the drilling industry. Downhole survey instruments are typically deployed and retrieved from a drill hole, drill string or casing by means of a cable, wire or rope. By arranging the mentioned rotation member of the present invention in engagement with the cable, wire or rope, the distance of the cable, wire or rope can be measured as the downhole survey instrument is lowered down the drill hole, drill string or casing. Surveying may commence at the top of the drill hole and continue all the way to the bottom of the drill hole and be repeated as the survey instrument is retrieved. Lowering and retrieving the cable, wire or rope is typically done with a winch, however push/pull rodder systems or hand force may in some cases be used.In one embodiment of the present invention, the system according to the present invention is integrated as a part of a counter assembly that contains a measuring wheel with contact to the cable, wire or rope. Accordingly, the rotation member in the present invention is thus the measuring wheel of the counter assembly.In accordance with a further embodiment of the present invention, the rotation member is a pulley wheel guiding the cable, wire or rope down the drill hole, drill string or casing to be surveyed. The measurement principle according to the present invention may also be utilized via indirect engagement/contact with the item or surface to be measured. An example of such an embodiment is wherein the rotation member is a winch drum, where the outer diameter of the drum would be related to the amount of cable, wire or rope left on it, making it more complex to determine accurate depth data.In the mentioned drilling example, when starting a survey, the downhole survey instrument is placed in the top section of the drill hole, drill string or casing, and the depth data is adjusted to zero. As the downhole survey instrument is lowered down the drill hole, drill string or casing, depth data is continuously transmitted and displayed at the user terminal. The direct knowledge of the current depth allows the operator to slow down the cable, wire or rope speed as the downhole survey instrument nears the bottom or top of the drill hole, drill string or casing, or at any other depths a lower, or higher, speed is desired.Once a survey is finished, the depth data is used to relate the survey data to the correct position in the drill hole, drill string or casing. The depth data may either be stored in the user terminal continuously during the survey process, or stored internally in the memory of the system for distance measurement and transferred to the user terminal after the end of survey. The latter gives extra security in case the wireless communication is temporarily lost during the survey process. By the present invention is further provided a method and system that requires few components and which is plain to assemble and dismantle, as well as enable easy maintenance and replacement. By the present invention is provided a solution that is easy to protect for harsh environments, such as dirt and water.The present invention further provides a solution that is capable of handling challenging conditions with vibrations, shocks and high radial forces present in many application areas. By this also follows that the present invention will be able to accurately measure the distance over a longer operational life compared to prior art solutions.The present invention provides a solution involving lower costs both for production, installation and maintenance, compared to prior art solutions.By the present invention is provided a solution that can be retrofitted to existing applications as well as be integrated in new applications.Further preferable features and advantageous details of the present invention will appear from the following example description, claims and attached drawings.ExampleThe present invention will bellow be described in further details with references to the attached drawings, where:Fig.1a-b are principle drawings of a system according to the present invention, Fig.2 is a non-limiting example of the measuring principle according to the present invention, and Fig.3 is a non-limiting usage example of the present invention.Reference is now made to Fig. 1a-b showing a principle drawing of system 100 for distance measurement according to one embodiment of the present invention. The system 100 according to the present invention comprises at least one rotating distance measurement assembly 110 formed by a rotation member 120 and at least one inertial sensor 210, 220, 230 or sensor assembly 200 arranged to or into the rotation member 120.The rotation member 120 according to the present invention has a circular known outer circumference 121. In accordance with the present invention, the rotation member 120 is a dedicated rotation member 120 of the system according to the present invention or a rotation member 120 already present in a system for an item 340 or a surface 500 to be distance measured. In the shown embodiment, the rotation member 120 is provided with a centre axle 130 enabling rotation of the rotation member 120 in relation to a support structure 400 (see Fig.3a-b).In the shown embodiment of the rotation member 120, shown as a wheel, has spokes 122 extending from the centre axle 130 and towards the outer circumference 121 (wheel rim). The rotation member 120 may further be a massive or cut out other object with a circular outer circumference 121 and wherein a centre axle 130 may be arranged, such as, but not limited to, pulleys, tubular members, disc-shaped members, etc.According to a further embodiment of the rotation member 120 according to the present invention, the outer circumference 121 is provided with a circumferentially extending recess (not shown) adapted for receiving and accommodating a cable, wire or rope 340 (see Fig. 3a) to be distance measured.The mentioned at least one inertial sensor 210, 220, 230 or sensor assembly 200 according to the present invention is arranged to or into the rotation member 120. In the shown example, the at least one inertial sensor 210, 220, 230 or sensor assembly 200 is arranged to a spoke 122 of the rotation member 120. If the rotation member 120 is massive, the rotation member 120 typically is provided with one or more recesses for receiving and accommodating the at least one inertial sensor 210, 220, 230 or sensor assembly 200 and detachably attaching it into the rotation member 120 by at least one fastening device 140, such as a clip-on/snap-on system or similar, or by nuts and bolts, screws or similar, enabling easy detachment of the at least one inertial sensor 210, 220, 230 or sensor assembly 200 from the rotation member 120. In the embodiment with the recess for receiving and accommodating the at least one inertial sensor 210, 220, 230 or sensor assembly 200, the recess will be designed for or comprises at least one fastening device 140 for fixation of the at least one inertial sensor 210, 220, 230 or sensor assembly 200. Other fastening devices 140 will be within the knowledge of a skilled person, to ensure that the at least one inertial sensor 210, 220, 230 or sensor assembly 200 is fixed to or into the rotation member 120.Reference is now made to Fig. 1b which is a block diagram of a system according to the present invention. The at least one inertial sensor 210, 220, 230 or sensor assembly 200 according to the present invention comprises at least one inertial sensor 210, 220, 230 configured to measure accelerations. According to the present invention, the at least one inertial sensor 210, 220, 230 or sensor assembly 200 comprises at least one accelerometer 210, or at least one gyroscope 220, or a combination, or an inertial measurement unit (IMU) 230 containing both accelerometer(s) and gyroscope(s).In accordance with one embodiment of the present invention, the at least one inertial sensor 210, 220, 230 or sensor assembly 200 comprises one accelerometer 210 configured to measure accelerations in at least two measurement axes. Alternatively, the at least one inertial sensor 210, 220, 230 or sensor assembly 200 comprises at least two single axis accelerometers (not shown) configured to measure accelerations in different measurement axes. The mentioned two measurement axes are preferably arranged perpendicular to each other and directed in the radial plane of the rotation member 120, such as the wheel.Reference is now also made to Fig. 2 showing output from a two-axis accelerometer 210. As the rotation member 120 is rotated in one direction, the accelerometer 210 data values present as a sine wave, where a full rotation of the rotation member 210 corresponds with a full cycle.If the rotational direction of the rotation member 120 changes, the accelerometer 210 output also changes direction. The sine waves in Fig. 2 illustrates two cycles in one direction followed by two cycles in the opposite direction, indicating that the rotation member 120 has first been rotated two rotations in one direction followed by two rotations in the opposite direction. The travelled distance is thus given as the 2 x the outer circumference of the rotation member 120 in each direction, ending back at the starting point.While any distance may be calculated this way by carefully analyzing the sine wave, it is in a digital sense easier to utilize the inertial sensor data output directly. When the maximum and minimum inertial sensor output is known, the angular position of any data output may be calculated using basic trigonometry. This way the angular starting position is known and can be recalculated any time the data output changes. By adding all changes in angular position occurring over the measurement period and subtracting the angular starting position the total angular change is found. The distance may now be calculated as Distance = π x radius of rotation member x angular change, where angular change is expressed in radians and include the number of revolutions.The use of two perpendicular accelerometer 210 axes secures that changes in rotational direction of the rotation member 120 can always be detected. If only measuring along one axis it will not be possible to detect a change in rotational direction that occurs at the top or bottom of the sine wave (max/min amplitude). From the maximum value, the accelerometer 210 output will reduce independent of the direction the rotation member 120 is rotating, and opposite from the minimum value. Adding a second accelerometer 210 axis secures that usable data is available when one axis is at maximum or minimum, securing that changes in direction can be detected at all times.In accordance with a further embodiment of the present invention, the at least one accelerometer 210 is configured to measure in a third accelerometer axis being perpendicular to the rotation member 120, parallel with the rotation member 120 axle axis. This will provide information about possible rotation member 120 tilt angle and total acceleration. In an alternative embodiment, the sensor assembly 200 comprises a third single axis accelerometer 210 for this.It should be mentioned that the at least one sensor assembly 200 may comprise a combination of single axis, two-axis and three-axis accelerometers 210 to achieve the above mentioned three measurement axes.A rotating gyroscope 220 produce data signals that are directly proportional to the rotation speed. With knowledge of time, this may be utilized to calculate angular change directly. However, as gyroscope sensors are commonly prone to drift the sensor data may over time become unreliable. The drift causes the gyroscope sensor to register a higher or lower angular rate than the actual. While some drift may be compensated for, for instance by stopping the rotation for a certain period and detecting changes that occur, the procedures affect operation and may not achieve full compensation of the drift. Instead of relying solely on a gyroscope sensor for angular change determination, the gyroscope sensor may be combined with accelerometer sensor(s). As described earlier, each sensor type may be used to compensate and correct for the other and significantly improve the distance measurement accuracy of the system. The system according to the present invention further comprises an embedded or external control unit 240 configured, by comprising means and/or software, to retrieve sensor data from the at least one inertial sensor 210, 220, 230 or sensor assembly 200.The control unit 240 is configured, by comprising means and/or software, to store sensor data from the at least one inertial sensor 210, 220, 230 or sensor assembly 200 in an internal memory 241 or an external memory.In accordance with one embodiment of the present invention, the control unit 240 is configured, by comprising means and/or software, for internal processing of the retrieved sensor data in real-time, or post-processing (offline).The control unit 240 is according to a further embodiment provided with wired or wireless communication means 242 or arranged to a communication module with wired or wireless communication means (not shown).In accordance with the present invention, the system further comprises a power system/unit 250 for powering the components of the system, mentioned above. Power to the system components is preferably provided by an energy storage (battery or battery pack), which may be either replaceable or rechargeable, and/or comprising energy harvesting means. A skilled person will be familiar with these alternatives and no further description is required herein.In accordance with the present invention, the measurement information is presented to a user on at least one embedded or external user terminal 260. The at least one user terminal 260 is, e.g., an embedded display or an external display, a computer or a handheld unit, such as a smart phone, tablet or similar, or a combination thereof. For communication with at least one external user terminal 260, the communication means 242 are preferably wireless, but may also be wired, especially for post-processing applications.According to one embodiment of the present invention the mentioned wireless communication means 242 for communication with the at least one external user terminal 260 comprises an antenna system as described in NO344403 (in the name of the applicant) is utilized. Other antenna systems, and wired solutions, are also possible, which solutions will be within the knowledge of a skilled person. In a further embodiment of the present invention, the at least one external user terminal 260 is configured, by comprising means and/or software, to process the stored/logged sensor data in realtime or post-processed (offline).The user terminal 260 is in addition to displaying information preferably also configured, by comprising means and/or software, to control the settings of the at least one inertial sensor 210, 220, 230 or sensor assembly 200, such as sampling rate, start or stop of the logging process, power saving, calibration, etc. If the system is used to another application one will have to update the system with the circumference, radius, etc. used in the mentioned calculations.In accordance with one embodiment of the present invention the at least one inertial sensor 210, 220, 230 or sensor assembly 200 is arranged in a protective housing 201 adapted to the required conditions to protect the components from dirt and water. The control unit 240 and/or user terminal 260 may also be arranged in separate housings for the same reason or embedded in the same housing 201 as the at least one inertial sensor 210, 220, 230 or sensor assembly 200.Reference is now made to Fig.3a-b showing different applications for use of the distance measuring principle according to the present invention.Fig. 3a shows a typical setup for a borehole survey system 300 with a winch 310 controlling deployment and retrieval of a downhole survey instrument 320 to and from a borehole, drill string or casing 330 by means of a wire, cable or rope 340.The mentioned winch 310 comprises a drum 311 on which the mentioned wire, cable or rope 340 is reeled and at least one controllable motor 312 controlling the deployment and retrieval of the wire, cable or rope 340, as well as the wire, cable or rope speed, and thus also the deployment and retrieval of the downhole survey instrument 320.The system according to the present invention is in this usage example implemented by a rotation member 120 in the form of a part of a pulley system guiding the wire, cable or rope 340 into the borehole, drill string or casing 330, and wherein the downhole survey instrument 320 is attached to the free end of the wire, cable or rope 340.In the shown embodiment, the pulley system is formed by the mentioned rotation member 120 in the form of a guide wheel, and a support structure 400, such as a stand or attachment system, wherein the rotation member 120 is arranged rotatably to the support structure 400 via the centre axel 130, and wherein the at least one inertial sensor 210, 220, 230 or sensor assembly 200 is arranged to and fixed to a spoke 121 of the rotation member 120. The support structure 400 is positioning and securing the rotation member 120 in a suitable position near an upper end of the borehole, drill string or casing 320.Accordingly, the at least one inertial sensor 210, 220, 230 or sensor assembly 200 will rotate with the guide wheel/rotation member 120 as the wire, cable or rope 340 is discharged from or reeled onto the winch 310 as the downhole survey instrument 320 is lowered or elevated, respectively, in the borehole, drill string or casing 330.The at least one inertial sensor 210, 220, 230 or sensor assembly 200 transfers the sensor (measurement) data wirelessly to the user terminal 260 for displaying. The sensor data is sent continuously or at high frequency giving the user direct feedback on the current depth as the downhole survey instrument 320 is lowered down or retrieved from the borehole, drill string or casing 330.With this information the user can monitor the speed during the survey, and reduce the speed as the downhole survey instrument 320 is closing in on the borehole, drill string or casing 330 bottom or upper end to avoid damages to the downhole survey instrument 320 and unsafe situations. In Fig. 3b is shown another embodiment where the rotation member 120 with the at least one inertial sensor 210, 220, 230 or sensor assembly 200 is arranged to a support structure 400 enabling movement of the rotating distance measurement assembly 110 in contact with a surface 500 by the rotation member 120 for distance measurement, such that the rotation member 120 is rotated as the rotating distance measurement assembly 110 is moved in relation to the surface 500.Alternatively, the at least one rotating distance measurement assembly 110 is arranged to a stationary support structure 400 enabling movement of the surface 500 to be distance measured in relation to support structure 400/rotating distance measurement assembly 110 with the rotation member 120 in contact with the surface 500, such that the rotation member 120 is rotated as the surface 500 moves in relation to the support structure 400/rotating distance measurement assembly 110.Examples of other applications is surface traveling manual or automated vehicles or crafts, hereunder bicycles, cars, remotely operated vehicle, etc. having at least one rotation member/wheel that at least one inertial sensor 210, 220, 230 or sensor assembly 200 can be arranged to or embedded in. The system according to the present invention enables the calculation of velocity of the item or surface in all applications. In many applications it will be preferable to log velocity of the item or object during the distance measurement, such as e.g. velocity of the cable, wire or rope during a drill hole survey. In accordance with one embodiment of the present invention, the internal or external control unit 240, 260 is configured, by comprising means and/or software, to log time together with sensor data. One can then use the time between measure points and calculate the velocity based on this as. Accordingly, in accordance with one embodiment of the present invention, the internal or external control unit 240, 260 is configured, by comprising means and/or software, to calculate velocity of the item based on: Δdistance/Δtime. This also enables the calculation of velocity of the vehicles or crafts.In accordance with one embodiment of the present invention, the at least one rotation member 120 is provided with two or more inertial sensors 210, 220, 230 or sensor assemblies 200 with the same or different specifications at different locations. In this manner one may achieve redundancy or improved measurement results.In a further embodiment of the present invention, two or more rotating distance measurement assemblies 110 are used, with the same or different specifications, for measuring distance of an item 340 or surface 500. E.g. by integration in two different pulleys of a pulley system.According to a further embodiment of the present invention, the at least one rotating distance measurement assembly 110 comprises two or more rotation members 120 provided with at least one inertial sensor 210, 220, 230 or sensor assembly 200, with the same or different specifications, for measuring distance of an item 340 or surface 500. E.g. by integration of two independent parallel rotation members 120 in a support structure 400, either arranged in longitudinal direction or transversal direction, wherein both rotation members 120 are independently in contact with the item 340 or surface 500.In these latter embodiments one also achieves redundancy or improved measurement results. The above described embodiments may be combined to form modified embodiments within the scope of the attached claims.
Claims
Claims1. Method for distance measurement of an item (340) or surface (500) comprises arranging at least one rotating distance measurement assembly (120) in engagement with the item (340) or surface (500) to be distance measured, the at least one rotating distance measurement assembly (110) being formed by a rotation member (120) and at least one inertial sensor (210, 220, 230) or sensor assembly (200) arranged thereto or embedded therein, wherein the at last one inertial sensor (210, 220, 230) or sensor assembly (200) forms basis for determining angular change, wherein the method comprising:applying rotation to the rotation member (120) by movement of the rotation member (120) along the item (340) or surface (500) or by movement of the item (340) or surface (500) applying rotation to the rotation member (120),during the rotation of the rotation member (120) measuring acceleration and/or angular rate with the at least inertial one sensor (210, 220, 230) or sensor assembly (200), andcalculating the distance of the item (340) or surface (500) based on determined angular change and outer circumference of the rotation member (120).2. Method according to claim 1, wherein measuring accelerations and/or angular rate by using at least one accelerometer (210), at least one gyroscope (220), or a combination thereof, or an inertial measurement unit (230).3. Method according to claim 2, wherein using at least one gyroscope (220) to detect and quantify change in speed and centripetal acceleration of the rotation member (120).4. Method according to claim 3, wherein measuring or calculating angular rate or change in acceleration.5. Method according to claim 3, wherein using sensor data from at least one gyroscope (220) as direct input in the distance measurement calculation or to compensate sensor data for the at least one accelerometer (210).6. Method according to claim 2, wherein analysing the sine wave cycles from measured accelerations from the at least one inertial sensor (210, 220, 230) or sensor assembly (200) to provide a measure of angular change of the rotation member (120).7. Method according to claim 6, wherein calculating distance of the item or surface by number of rotations of the rotation member (120) x outer circumference of the rotation member (120).8. Method according to claim 7, wherein calculating distance of the item (340) or surface (500) from: π x radius of rotation member (120) x angular change.9. Method according to claim 7, wherein calculating depth of a deployed downhole survey (320) instrument in a drill hole, drill string or casing (330) from: π x radius of rotation member (120) x angular change.10. System (100) for distance measurement of an item (340) or surface (500), wherein the system (100) comprises at least one rotating distance measurement assembly (110) in engagement with the item (340) or surface (500) to be distance measured, the at least one rotating distance measurement assembly (110) being formed by a rotation member (120) and at least one inertial sensor (210, 220, 230) or sensor assembly (200) arranged thereto or embedded therein,wherein the at least one inertial sensor (210, 220, 230) or sensor assembly (200) is configured to measure accelerations and/or angular rate when the rotation member (120) is rotated by movement of the rotation member (120) along the item (340) or surface (500) or by movement of the item (340) or surface (500) applying rotation to the rotation member (120),wherein the system (100) comprises an internal or external control unit (240, 260) configured, by comprising means and/or software, to calculate distance of the item (340) or surface (500) based on the measured sensor data and outer circumference of the rotation member (120).11. System (100) according to claim 10, wherein the at least one inertial sensor (210, 220, 230) or sensor assembly (200) is detachably arranged to or embedded into the rotation member (120).12. System (100) according to claim 10, wherein the at least one inertial sensor (210, 220, 230) or sensor assembly (200) comprises at least one accelerometer (210), at least one gyroscope (220), or a combination thereof, or at least one inertial measurement unit (230).13. System (100) according to claim 12, wherein the at least inertial one sensor (210, 220, 230) or sensor assembly (200) is configured for measuring angular rate or change in acceleration.14. System (100) according to claim 12, wherein the at least one inertial sensor (210, 220, 230) or sensor assembly (200) comprises:- at least two single axis accelerometers (210), arranged with perpendicular measurement axes, - at least one two-axis accelerometer (210), configured with two perpendicular measurement axes,- at least one three-axis accelerometer (210), configured with two perpendicular measurement axes and a third measurement axis perpendicular to the rotation member (120), or- a combination of single axis, two-axis and/or three-axis accelerometers (210).15. System (100) according to claim 12, wherein the internal or external control unit (240, 260) is configured, by comprising means and/or software, to determine angular change from the measured angular rate and/or change in acceleration.16. System according to claim 12, wherein the at least one gyroscope (220) is configured to detect and quantify change in speed and centripetal acceleration of the at least one rotation member (120).17. System (100) according to claim 16, wherein the internal or external control unit (240, 260) is configured, by comprising means and/or software, to use sensor data from at least one gyroscope (220) as direct input in the distance measurement calculation or to compensate sensor data for the at least one accelerometer (210).18. System (100) according to any preceding claim 10-17, wherein the internal or external control unit (240, 260) is configured, by comprising means and/or software, to analyse the sine wave cycles of the acceleration measurements from the at least one inertial sensor (210, 220, 230) or sensor assembly (200) to provide a measure of angular change of the rotation member (120).19. System (100) according to claim 18, wherein the internal or external control unit (240, 260) is configured, by comprising means and/or software, to calculating distance by number of rotations of the rotation member (120) x outer circumference of the rotation member (120).20. System (100) according to claim 19, wherein the internal or external control unit (240, 260) is configured, by comprising means and/or software, to calculate distance of the item or surface from:π x radius of rotation member (120) x angular change.21. System (100) according to claim 19, wherein the internal or external control unit (240, 260) is configured, by comprising means and/or software, to calculate depth of a deployed downhole survey instrument in a drill hole, drill string or casing from:π x radius of rotation member (120) x angular change.22. System (100) according to any preceding claim 10-21, wherein the system (100) comprises a user terminal (260) for displaying distance measurements and/or depth.23. System (100) according to any preceding claim 10-22, wherein the at least one inertial sensor (210, 220, 230) or sensor assembly (200) is arranged in a protective housing (201).
Drawings

Priority

No priority

Patent classes

IPC classesG01B 7/02G01B 3/12E21B 47/09E21B 47/04CPC classesG01B 7/02G01B 7/026G01B 3/12E21B 47/09E21B 47/04

Citations

DE 102019200686 A1 (A1)US H1289 H (H)

Applicants, owners and inventors

Owners
Devico AS
Postboks 318 Heimdal 7474 TRONDHEIM NO (TRONDHEIM Municipality, Trøndelag county)Org. number: 947402633Inventors
John Flåm
c/o Devico AS, Postboks 318 Heimdal 7474 TRONDHEIM NO (TRONDHEIM Municipality, Trøndelag county)
Geir Bjarte Havsgård
c/o Devico AS, Postboks 318 Heimdal 7474 TRONDHEIM NO (TRONDHEIM Municipality, Trøndelag county)

Agent

ACAPO ONSAGERS AS
ACAPO ONSAGERS AS

Org. number: 932214636

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Edvard Griegs vei 1 5059 BERGEN NO (BERGEN Municipality, Vestland county)
Org. number: 932214636
Reference: P20230392NO

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