Water Cut Measurement Density Correction
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Solution Overview
Problem
Existing on-line permittivity-based analyzers for measuring water content in petroleum face challenges due to uncertainties related to ambient temperature, improper calibration, insufficient mixing, and variations in crude oil properties, leading to inaccurate measurements, especially at high water cuts and low densities.
Innovation Solution
The method involves using a correction factor based on physical density measurements to improve the accuracy of water fraction measurements, capping the correction at a modest water fraction of 5% to prevent overcorrection at higher water levels, and employing on-line densitometers to estimate dry oil density, thereby reducing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If density correction is applied to improve water cut measurement accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by introducing density as a correction parameter to improve water cut measurements. The system measures density variations in the petroleum stream and uses these parameter changes to correct permittivity-based water cut readings, thereby improving measurement accuracy without requiring complex additional hardware
Solution Approach 2:
The patent implements feedback by continuously monitoring density measurements and using this information to adjust and correct water cut measurements in real-time. The corrected water cut values are fed back into the measurement system to improve ongoing accuracy, creating a closed-loop correction mechanism that enhances precision while maintaining operational simplicity
2Productivity
If on-line real time analyzers are used to measure water content, then productivity improves, but measurement precision deteriorates due to uncertainty sources
Solution Approach 1:
The patent introduces density measurement as an intermediary parameter that mediates between the permittivity-based water cut measurement and the actual water content. This intermediary density data helps account for variations in petroleum properties that affect permittivity readings, thereby improving measurement precision while preserving the real-time productivity benefits of on-line analysis
Solution Approach 2:
The system addresses precision deterioration by dynamically adjusting measurements based on density parameter changes. As density varies due to temperature, composition, or water content changes, the system uses these parameter variations to correct the water cut readings, maintaining accuracy despite the continuous operation requirements of real-time analysis
3Measurement precision
If composite samplers are used to determine water content, then measurement precision improves, but loss of time increases
Solution Approach 1:
The patent replaces the mechanical composite sampling system with an on-line permittivity-based analyzer enhanced by density correction. This substitution eliminates the need for physical sampling, batching, and laboratory analysis, providing real-time water cut measurements with precision comparable to or better than composite samplers, thereby eliminating the time loss associated with batch processing
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 results in more accurate measurements at high and low water cuts, simplifying implementation and reducing errors associated with density variations, enhancing the reliability of water content analysis in petroleum pipelines.
Implementation Method 1
The basis of the effect of the wet and dry oil densities is that such on-line analyzers detect changes in the polar moment of a molecule, which affects the electrical properties of permittivity and thus the dielectric constant
Implementation Method 2
A measurement of physical density is used to supply a correction factor for the electrical on-line characterization of water cut
Data Source
AI summary
Methods of correcting on-line analyzer measurements of the content of a first component, e.g., water, in a multiple-component fluid, e.g., petroleum, are provided. The first component content measurements in a flowing multiple-component fluid may be taken using an on-line analyzer. Mixture density measurements that correspond to the first component content measurements may also be taken using a densitometer. Next, an offset value for each first component content measurement may be calculated based on the following equations:if the first component content measurement is ≦ a predetermined content set point, offset=slope correction factor×(the corresponding mixture density measurement−a calibration density); and (a)if the first component content measurement is > the predetermined content set point, offset=the offset value calculated at the predetermined content set point. (b)The first component content measurements may then be corrected based on the respective offset values.