Dielectric Resonator Sensor for Wet Gas Water Content

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Solution Overview

Problem

Current measurement technologies for water content in wet gas flows, particularly at low water volume fractions, face limitations in accuracy due to the dominance of oil and gas permittivity, leading to uncertainties in hydrate formation, scaling, and corrosion issues, especially when salinity from formation water is involved.

Innovation Solution

A dielectric resonator sensor is integrated into a pipeline to measure the resonance frequency and quality factor of a wet gas flow, allowing for precise calculation of water content and salinity by exploiting the sensitivity of the sensor to the permittivity of the fluid mixture, even at low water volume fractions, using a surface-sensitive design that minimizes radiation and interference from gas and oil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If microwave resonance method is used to measure water content in wet gas flow, then measurement sensitivity is improved, but measurement precision deteriorates at low water volume fractions due to dominance of oil and gas permittivity

Engineering Contradiction:
Improvewater content measurement accuracyVSAvoidmeasurement reliability at low WVF
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by using a surface-sensitive dielectric resonator sensor that concentrates the electromagnetic field near the pipe wall where liquid film flows. This localized field measurement approach detects water content specifically at the wall region rather than averaging over the entire pipe cross-section, enabling reliable detection at low WVF where bulk measurement methods fail due to oil and gas permittivity dominance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces an intermediary approach by using the pipe wall as a reference interface and measuring the liquid film formed on the wall surface. The dielectric resonator sensor acts as an intermediary device that couples the electromagnetic field to the liquid film through the pipe wall, enabling indirect but accurate water content measurement even when bulk water content is very low.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If conventional microwave sensors are used, then measurement coverage is improved, but detection sensitivity deteriorates for low water content due to signal averaging over entire flow cross-section

Engineering Contradiction:
Improvedetection coverageVSAvoidlow water content detection limit
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies local quality by using a surface-sensitive dielectric resonator sensor that concentrates the electromagnetic field near the pipe wall where liquid film flows. This localized field measurement approach detects water content specifically at the wall region rather than averaging over the entire pipe cross-section, enabling reliable detection at low WVF where bulk measurement methods fail due to oil and gas permittivity dominance.

Inventive Principle:
Principle #3Local quality

3Reliability

If salinity measurement capability is added to detect formation water, then operational safety is improved, but device complexity increases

Engineering Contradiction:
Improvecorrosion and scaling risk detectionVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a multi-functional dielectric resonator sensor system that simultaneously measures water content, liquid film thickness, and salinity using a single sensor platform. The system performs multiple measurements (resonance frequency, Q-factor, impedance) with one device, eliminating the need for separate sensors for each parameter and reducing overall system complexity despite the enhanced functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies parameter changes by utilizing different electrical measurement parameters (resonance frequency, quality factor Q, impedance) from the same dielectric resonator sensor to extract multiple physical properties (water content, salinity, film thickness). By analyzing variations in these electrical parameters in response to changes in the liquid film properties, the system achieves multi-parameter measurement without adding physical sensor complexity.

Inventive Principle:
Principle #35Parameter changes

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

The solution enhances the accuracy of water content and salinity measurements in wet gas flows, enabling early detection of formation water and reducing corrosion and scaling risks by providing a higher sensitivity and lower detection limits, thus improving operational efficiency in hydrocarbon pipelines.

Implementation Method 1

A dielectric resonator sensor (3) integrated in a pipeline (2) for transporting a wet gas flow (1)... adapted for forming a time varying electric fringing field extending from said resonator sensor (3)... adapted for measuring a resonance frequency of said resonator sensor (3), and a quality factor of a resonance signal of said resonator sensor (3)

Methodology Applied
Scientific EffectDielectric resonance: Resonance

Implementation Method 2

Because the permittivity of water is high (in the order of 80) compared to that of oil (in the order of 1.5 - 3) or gas (even lower than for oil) the permittivity of a mixture of these three constituents is dominated by the contribution from water.

Methodology Applied
Scientific EffectPermittivity: Dielectric Permittivity

Data Source

PatentEP2104837B1Flow measurement
Publication Date: 2017.09.27 ROXAR FLOW MEASUREMENT
  • EP2104837B1 patent drawingFigure 1~2
  • EP2104837B1 patent drawingFigure 3~4
  • EP2104837B1 patent drawingFigure 5~6

AI summary

This invention relates to a measuring instrument for measurement of a flow (1) comprising - a dielectric resonator sensor (3) arranged in a pipeline (2), said resonator (3) having a surface (4) facing a flow volume, - a sensor drive unit (12) being coupled to said sensor (3) and which is adapted to provide a driving or excitation signal to said sensor (3) resulting in the excitation of an electromagnetic resonance in said sensor causing a fringing electromagnetic field (5) adjacent to said surface (4) facing said wet gas flow (1), - a recording unit (10) coupled to said sensor (3) and which is adapted to measure a resonance property of said sensor (3) while said wet gas flow (1) moves past said sensor surface (4), and - a processing unit (11) which is adapted to estimate a property of at least a part of said wet gas flow (1).