Well Tool Position Sensing Using Optical and Radiation Tracking
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Solution Overview
Problem
Conventional position measuring devices for well site tools, such as position sensor assemblies (PSAs), face precision issues due to friction and magnetic hysteresis, leading to imprecision and frequent recalibration needs, which increase operational costs and time.
Innovation Solution
The use of optical-based position sensor assemblies, vibration sensors, and radiation detection systems that reduce magnetic coupling and internal friction, allowing for more accurate and less frequent position measurements of moving mechanisms in well site tools, such as fluid valves, without the need for frequent recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position sensor assemblies utilize magnets to couple the PSA to the fluid valve system, then the position measurement can be obtained, but friction and magnetic hysteresis interfere with the smooth movement of the positioning sensor resulting in loss of precision and calibration
Solution Approach 1:
The patent replaces the conventional magnetic coupling system with an optical system. A magnet is coupled to the moving mechanism, and a magnetometer on the position sensor assembly measures the magnetic field to determine position, eliminating direct mechanical contact and friction. This substitution of mechanical coupling with magnetic field sensing resolves the technical contradiction by removing friction and magnetic hysteresis while maintaining measurement precision.
Solution Approach 2:
The patent introduces a magnet as an intermediary between the moving mechanism and the position sensor assembly. The magnet is coupled to the moving mechanism, and the magnetometer detects its position through magnetic field measurements without physical contact. This intermediary approach allows position measurement while eliminating direct mechanical interaction that causes friction and hysteresis.
2Reliability
If the moving mechanism is fully moved to one position for periodic calibration, then the positioning can be recalibrated, but this results in loss of time and imprecision of positioning during the calibration process
Solution Approach 1:
The patent enables continuous self-calibration by maintaining the magnet in constant contact with the moving mechanism throughout its range of motion. The magnetometer continuously tracks the magnet's position, allowing the system to automatically reference known positions during normal operation without requiring separate calibration cycles. This eliminates the need for periodic full-movement calibration while maintaining positioning reliability.
Solution Approach 2:
The patent implements continuous position measurement and tracking throughout the moving mechanism's operational range. The magnetometer continuously monitors the magnet's position, providing uninterrupted position data and enabling continuous verification of positioning accuracy without stopping or pausing for calibration. This continuous measurement approach eliminates calibration downtime while maintaining reliability.
3Loss of information
If conventional PSA magnet systems are used, then position information can be obtained, but friction interferes with the smooth movement of the positioning sensor leading to loss of calibration
Solution Approach 1:
The patent replaces mechanical coupling between the position sensor assembly and the moving mechanism with magnetic field sensing. The magnetometer detects the magnet's position through non-contact magnetic field measurements, eliminating mechanical friction and allowing smooth movement without interference. This maintains accurate positioning information while ensuring ease of operation throughout the full range of motion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These solutions enhance the accuracy and responsiveness of position measurements, reducing recalibration frequency by 50% to 70% and minimizing position precision loss, while eliminating magnetic hysteresis effects and reducing the number of mechanical parts.
Implementation Method 1
a position sensor assembly (PSA) housing capable to produce optical radiation, and to detect a reflection of the optical radiation
Implementation Method 2
a PSA sub-assembly, magnetically coupled to the moving mechanism
Data Source
AI summary
This disclosure presents an apparatus to improve the position sensing of a moving mechanism, such as a fluid valve located within a borehole. The apparatus can utilize a light beam or an optical fiber to measure changes in the position sensor. The smaller and lighter apparatus can improve the accuracy of the sensing mechanism. In addition, three systems are presented. The first system utilizes a vibration sensor, such as a MEMS, and an accelerometer to calculate changes in the mechanism position of the moving mechanism. The second system utilizes a radiation source and detector combination, along with a moving radiation shield to provide more accurate position sensing than conventional techniques. In addition, a lens-based system is presented, that when combined with a radiation source, can calculate position information by detecting the diffusion or dispersal of the radiation against a radiation detector.