Virtual Flow Meter Sensor Uncertainty Calibration
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Solution Overview
Problem
Virtual flow meters in resource production contexts face challenges in maintaining accuracy due to sensor inaccuracies and model errors, particularly in subsea locations, where conventional calibration methods relying on mean values can be misleading and fail to account for measurement uncertainties.
Innovation Solution
A processor-based controller system that calculates and accounts for uncertainties in outlet pressure and temperature by analyzing sensor data from pressure and temperature sensors, using a combination of mean values and measurement errors to determine conservative uncertainty boundaries, thereby improving calibration and estimation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional calibration methods using mean values are used, then the calibration process is simple, but the accuracy and reliability of virtual flow meter readings deteriorate due to unaccounted sensor uncertainties
Solution Approach 1:
The patent applies preliminary action by pre-calculating uncertainty boundaries for sensor measurements before performing calibration. The system determines conservative uncertainty boundaries for pressure and temperature sensor readings in advance, then uses these pre-computed boundaries to guide the calibration process, ensuring that uncertainty propagation is accounted for from the outset rather than attempting to correct inaccuracies after calibration.
Solution Approach 2:
The patent introduces uncertainty boundaries as an intermediary element between sensor measurements and calibration results. These boundaries act as a mediator that quantifies and propagates measurement uncertainties through the calibration process, providing a conservative estimate of the reliability of virtual flow meter readings without requiring complex real-time uncertainty analysis.
2Reliability
If sensor measurement uncertainties are explicitly accounted for, then the reliability of calibration improves, but the complexity of the calibration process increases
Solution Approach 1:
The patent applies parameter changes by transforming the calibration approach from using single mean values to using uncertainty boundaries defined by conservative parameter ranges. The system changes the calibration parameters from deterministic mean values to probabilistic ranges that account for sensor uncertainties, thereby improving reliability while maintaining a structured calibration process.
Solution Approach 2:
The patent segments the calibration process into distinct steps: (1) determining uncertainty boundaries for each sensor measurement, (2) propagating these uncertainties through the virtual flow meter model, and (3) using the propagated uncertainties to assess calibration reliability. This segmentation makes the complex uncertainty analysis manageable and systematic rather than overwhelming.
3Productivity
If virtual flow meters are deployed in subsea locations, then productivity and cost-effectiveness improve, but measurement accuracy deteriorates due to difficult tuning and unaccounted uncertainties
Solution Approach 1:
The patent implements feedback by using the determined uncertainty boundaries to continuously assess and validate virtual flow meter performance in subsea locations. The system provides feedback on measurement reliability based on propagated uncertainties, enabling operators to monitor and maintain accuracy without requiring physical access for tuning, thus preserving the productivity benefits of subsea deployment.
Solution Approach 2:
The patent enables self-service by allowing the virtual flow meter system to automatically determine and propagate uncertainty boundaries without requiring external calibration interventions. The system self-assesses its measurement reliability by computing uncertainty boundaries from its own sensor data and model parameters, eliminating the need for difficult manual tuning in remote subsea locations.
Data Source
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AI summary
The present approach relates to establishing metrics for the computation of uncertainty boundaries for mean values for pressure and temperature drop error and mean values for mass flow error. Using such metric, sensor inaccuracies may be accounted for in the calibration and/or estimation processes of a virtual flow meter. For example, these values may be employed in the assessment of improvement in a calibration process of virtual flow meters, which will facilitate maintaining the accuracy of such virtual flow meters