Density-Viscosity Sensor Resonance Frequency and Quality Factor Determination
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Solution Overview
Problem
Existing density and viscosity sensors for subterranean formation fluids face limitations in accurately determining resonance frequency and quality factor due to the exclusion of secondary resonance modes and baseline drift, which restricts their operating range, especially for high viscosity fluids.
Innovation Solution
The method involves using a density-viscosity sensor with a resonating element in a downhole tool's flowline, processing data to determine resonance frequencies and quality factors based on both primary and secondary resonance modes, and accounting for background drift using nonlinear regression models to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only primary resonance mode is considered in the measurement model, then the device complexity is reduced, but the measurement precision deteriorates due to inaccurate determination of resonance frequency and quality factor
Solution Approach 1:
The patent segments the resonance response into multiple distinct modes (primary and secondary resonance modes), each characterized by separate parameters (amplitude, frequency, quality factor). This segmentation allows the complex multi-mode response to be analyzed through simpler individual mode components, resolving the contradiction by making the measurement model manageable while capturing all relevant physical phenomena for accurate measurement.
Solution Approach 2:
The patent transitions from a single-dimensional (primary mode only) analysis to a multi-dimensional analysis by incorporating secondary resonance modes as additional dimensions in the measurement model. This dimensional expansion enables simultaneous characterization of multiple resonance phenomena, improving measurement precision without overwhelming complexity through systematic parameter estimation techniques.
2Device complexity
If secondary resonance modes are excluded from the measurement model, then the device complexity is reduced, but the reliability deteriorates especially for high viscosity fluids
Solution Approach 1:
The patent segments the total resonance response into distinct primary and secondary mode contributions, allowing each mode to be independently characterized and combined. This segmentation enables the model to reliably capture the complex behavior of high viscosity fluids without overwhelming complexity, as each segmented mode can be processed separately through systematic parameter estimation.
Solution Approach 2:
The patent changes the parameters of the measurement model by introducing additional parameters for secondary resonance modes (amplitude, frequency, quality factor) alongside the primary mode parameters. This parameter expansion enables the model to adapt to different fluid conditions, particularly high viscosity fluids where secondary modes become significant, thereby improving reliability while maintaining manageable complexity through efficient parameter estimation methods.
3Device complexity
If baseline drift is not accounted for in the measurement model, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The patent introduces baseline drift parameters as intermediary elements in the measurement model that mediate between the raw sensor signal and the resonance mode parameters. These intermediary drift parameters capture low-frequency variations in the baseline, allowing the resonance mode parameters to be accurately extracted without being contaminated by baseline variations, thereby improving measurement precision while adding only minimal complexity.
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 allows for more accurate determination of fluid density and viscosity by considering multiple resonance modes and drift, enhancing the sensors' operational range and reliability.
Implementation Method 1
The sensors measure the mechanical resonance of the resonating element vibrating in the fluid flowing in the flowline
Implementation Method 2
outputting voltage-versus-time data that conforms to a simple damped harmonic model
Data Source
AI summary
Methods and apparatus for obtaining data from a density-viscosity (DV) sensor of a downhole tool, wherein the DV sensor comprises a resonating element disposed in a fluid flowing in a flowline of the downhole tool, and determining a resonance frequency and quality factor of the resonating element utilizing a nonlinear regression and/or a plurality of resonance modes exhibited by the obtained data.