Dual-Probe Electromagnetic Sensing for Multiphase Flow Measurement

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Solution Overview

Problem

Existing methods for measuring liquid flow properties in multiphase flows with high gas volume fractions (GVFs) above 95% are inaccurate and costly, particularly in wet-gas-wells, due to issues with separation and mixing devices that disrupt flow and fail to accurately measure liquid holdup and water-liquid ratio.

Innovation Solution

A system using dual probes with different sensitivity depths, configured as radio-frequency, microwave, or millimeter-wave electromagnetic sensing probes, is employed to measure the properties of a multiphase mixture flowing through a conduit, generating an annular flow and processing apparent permittivity measurements to determine liquid phase depth, fraction, and water-liquid ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separation and mixing devices are introduced into the pipeline to measure liquid flow properties, then measurement capability is provided, but device complexity increases and pressure drop increases

Engineering Contradiction:

Improveliquid flow property measurementVSAvoidseparation and mixing devices

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical separation and mixing devices with electromagnetic sensing probes that non-intrusively measure liquid flow properties. The probes detect permittivity changes in the multiphase flow without requiring mechanical intervention, thereby eliminating the complexity and pressure drop associated with mechanical devices while maintaining measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electromagnetic fields as an intermediary to measure liquid flow properties. Instead of directly interacting with the flow through mechanical devices, the system uses electromagnetic probes to sense changes in permittivity caused by liquid presence, providing a non-contact measurement approach that avoids mechanical complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If separation and mixing devices are introduced into the pipeline, then measurement capability is provided, but pressure drop in the pipeline increases

Engineering Contradiction:

Improveliquid flow property measurementVSAvoidpressure drop

Core Design Contradiction:

Measurement precisionVSStress or pressure

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The multiphase flow itself serves as the measurement medium by naturally creating permittivity variations that the electromagnetic probes detect. The flow's own properties (liquid presence, permittivity changes) provide the measurement signal without requiring external mechanical devices to create measurement conditions.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If mixing method is used to measure liquid holdup and water-in-liquid ratio, then measurement capability is provided, but measurement accuracy deteriorates at high GVF

Engineering Contradiction:

Improveliquid holdup and water-in-liquid ratio measurementVSAvoidmeasurement accuracy at high GVF

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical mixing methods with electromagnetic sensing that directly detects liquid properties in the multiphase flow. The probes measure permittivity changes caused by liquid presence without requiring mixing, providing accurate measurements even at high gas volume fractions where mixing methods fail.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement approach from mechanical mixing to electromagnetic parameter detection. By measuring changes in permittivity (an electrical property) rather than relying on mechanical mixing processes, the system maintains measurement accuracy across a wide range of gas volume fractions including high GVF conditions.

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

This approach provides accurate measurements of liquid phase properties, including depth and water-liquid ratio, with reduced disruption and cost, by effectively measuring the multiphase mixture's properties in high GVF conditions.

Implementation Method 1

The probes are configured to have different sensitivity depths and are configured to contact the liquid phase of the multiphase mixture

Methodology Applied

Scientific EffectElectromagnetic sensing: Electromagnetic Induction

Implementation Method 2

using a first probe with a first sensitivity depth to measure a first apparent complex permittivity of the annular flow of the liquid phase

Methodology Applied

Scientific EffectPermittivity measurement: Dielectric Permittivity

Data Source

PatentUS8027794B2System and method for measuring properties of liquid in multiphase mixtures

Publication Date: 2011.09.27 SCHLUMBERGER TECH CORP

AI summary

This disclosure describes measuring properties of a multiphase mixture flowing in a pipe using probes with different sensitivity depths. By generating annular flow of the multiphase mixture in the pipe, the probes may be contacted with the liquid phase of the mixture flowing on an inner-wall of the pipe and apparent permittivities of the annular flow measured by the probes. These measured permittivities may be processed to determine liquid fraction of the annular flow and water-in-liquid ratio of the liquid phase of the annular flow.