NMR Sensor Calibration Lookup Table for Temperature Compensation
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Solution Overview
Problem
Existing technologies face challenges in accurately interpreting data collected by sensors in wellbores due to varying environmental conditions, particularly temperature changes, which affect the operation of nuclear magnetic resonance (NMR) sensing devices.
Innovation Solution
The implementation of a calibration process for NMR sensing devices, where data is collected at various temperatures and distances, allowing for the creation of calibration data that accounts for temperature-related effects. This data is used to improve the accuracy of interpretations made from data collected in wellbores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If NMR sensing devices are used in wellbores without temperature calibration, then device complexity is reduced, but measurement precision deteriorates due to temperature variations affecting data accuracy
Solution Approach 1:
The patent performs calibration measurements at multiple predetermined temperatures before actual wellbore operations. This preliminary action creates a temperature-compensated lookup table that stores calibration factors for different temperature conditions. During actual measurements, the system simply retrieves the appropriate calibration factors based on measured temperature, avoiding complex real-time compensation calculations while maintaining high measurement precision across varying temperatures.
Solution Approach 2:
The patent introduces temperature as an intermediary parameter that mediates between the physical condition (temperature) and the measurement accuracy. By measuring temperature and using it to select appropriate calibration factors from the lookup table, the system indirectly compensates for temperature effects on NMR measurements. This intermediary approach simplifies the overall system while maintaining accuracy, as temperature serves as a reliable proxy for predicting and correcting measurement deviations.
2Reliability
If calibration data is collected at multiple temperatures and distances, then reliability of wellbore determinations improves, but loss of time increases due to extensive calibration measurements
Solution Approach 1:
The patent segments the calibration process into discrete temperature points and radial distances. Instead of performing continuous or exhaustive calibration measurements, the system collects calibration data at specific segmented intervals (e.g., temperatures of 25°C, 50°C, 75°C, 100°C and specific radial distances from the tool center). This segmentation reduces the total number of measurements required while still providing sufficient coverage to ensure reliable wellbore determinations across the full operating range.
Solution Approach 2:
The patent applies partial action by collecting calibration data at a representative subset of temperature and distance conditions rather than all possible conditions. The calibration lookup table stores pre-computed factors for selected temperature points, and during operation, the system uses interpolation or nearest-neighbor matching to apply appropriate calibration factors. This partial approach achieves sufficient reliability without the time cost of exhaustive calibration across every possible condition.
3Measurement precision
If temperature compensation is implemented through calibration, then sensitivity of NMR sensing device improves, but device complexity increases due to additional calibration requirements
Solution Approach 1:
The patent creates a simplified digital copy of the temperature-compensated calibration relationships in the form of a lookup table. Instead of implementing complex physical compensation mechanisms or real-time calculation systems, the calibration factors for different temperatures are pre-computed and stored as digital data. During operation, the system simply reads the appropriate calibration factors from this digital copy based on the current temperature measurement, maintaining high sensing sensitivity while avoiding the complexity of real-time compensation algorithms or additional hardware.
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
This approach enables more accurate and repeatable determinations in wellbore environments by accounting for temperature variations, thereby enhancing the sensitivity and reliability of NMR sensing devices.
Implementation Method 1
transmitting a set of radio frequency (RF) signal pulses, each having a respective frequency and an energy; measuring, by the NMR sensing device, a set of electromagnetic responses to the transmitted set of RF signal pulses
Implementation Method 2
A magnetic field provided by a magnet of an NMR sensing device aligns at least some of the nuclear spins
Data Source
AI summary
Described herein are systems and techniques for improving accuracies of determinations made using a nuclear magnetic resonance (NMR) sensing device when the NRM sensing device collects data in a wellbore. NMR sensing devices include a magnet that provides a magnetic field that aligns the spins of protons in substances near the NMR sensing device. The magnetic field strength provided by this magnet affects the sensitivity of the NMR sensing device and affects frequencies that the NMR sensing device effectively uses when the NMR sensing device operates. Furthermore, the field strength of magnets used in an NMR sensing device varies with temperature. Since temperatures within a wellbore vary significantly and since these temperatures affect how an NMR sensing device operates, systems and techniques of the present disclosure collect calibration data in a calibration chamber such that data sensed by the NMR sensing device can be interpreted more accurately when temperatures change.