U-Bend Differential Pressure Metering for Multiphase Flow

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Solution Overview

Problem

Characterization of multiphase fluid flow is challenging due to complex flow characteristics influenced by factors such as pressure, temperature, composition, and conduit geometry, making accurate flow metering difficult, especially in oil and gas operations.

Innovation Solution

A system utilizing a U-bend configuration with multiple conduits and differential pressure sensors to measure and calculate mixture density and total flow rate of multiphase fluids, employing equations to determine density and flow rate based on differential pressures and gravity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional production techniques are used for flowmeters, then manufacturing cost and device complexity are reduced, but manufacturing precision and measurement precision deteriorate due to inability to capture small bubble features

Engineering Contradiction:
Improvebubble feature capture precisionVSAvoid3D imaging system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical/optical flowmeter components with acoustic imaging technology. Acoustic waves are used to detect and characterize bubbles and fluid flow, substituting traditional mechanical measurement mechanisms with a non-contact acoustic field-based system that can resolve small bubble features without complex mechanical structures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from conventional flow rate directly to bubble size distribution and fluid properties. By using acoustic wave interaction with bubbles (change in acoustic impedance), the system directly measures bubble characteristics rather than inferring them from flow rate, enabling precise capture of small bubble features.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If acoustic waves are used to detect bubbles and fluid, then measurement precision improves, but device complexity increases due to signal processing requirements

Engineering Contradiction:
Improvebubble size measurement precisionVSAvoidsignal processing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The acoustic imaging system performs multiple functions simultaneously: it detects bubble size, measures fluid flow rate, characterizes fluid properties, and identifies flow regime all using the same acoustic wave transmission and reception mechanism. This multi-functionality reduces the need for separate specialized sensors and processing systems for each measurement type.

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

Solution Approach 2:

The acoustic waves naturally interact with the bubbles and fluid, providing self-characterization of the medium. The acoustic impedance changes caused by bubbles automatically encode information about bubble size and fluid properties in the reflected/transmitted waves, reducing the need for external calibration systems or complex auxiliary measurement devices.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If acoustic waves are transmitted through fluid, then non-intrusive measurement is achieved, but energy loss increases due to wave absorption and scattering

Engineering Contradiction:
Improvenon-intrusive measurement capabilityVSAvoidacoustic wave energy loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The system uses periodic acoustic wave transmission through the fluid. By transmitting acoustic waves in periodic pulses rather than continuously, the system allows the acoustic field to dissipate between transmissions, reducing cumulative energy loss and preventing acoustic saturation while maintaining effective measurement capability during each pulse.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses acoustic wave energy sufficient to detect bubbles and characterize fluid without fully penetrating or excessively heating the fluid. The acoustic waves are designed to provide just enough energy to create detectable impedance changes from bubbles while minimizing absorption and scattering losses in the bulk fluid.

Inventive Principle:
Principle #16Partial or excessive action

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

Accurately determines total flow rate, mixture density, and phase flow rates of multiphase fluids, even in complex flow regimes and with non-negligible gas presence, without hazardous radioactive sources, and enhances flow metering accuracy.

Implementation Method 1

An acoustic wave is transmitted through a section of the pipe

Methodology Applied
Scientific EffectAcoustic wave transmission: Sound

Implementation Method 2

The acoustic wave reflects off any bubbles in the pipe section

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Data Source

PatentEP4558795B1Multiphase fluid flow characterization
Publication Date: 2026.04.29 SAUDI ARABIAN OIL CO
  • EP4558795B1 patent drawingFigure 1A
  • EP4558795B1 patent drawingFigure 1B
  • EP4558795B1 patent drawingFigure 1C

AI summary

A multiphase fluid is flowed from a flow pipe to a U-bend. Several differential pressures of the multiphase fluid flowing through the flow pipe and U-bend are measured. A mixture density of the multiphase fluid is determined at least based on the measured differential pressures. A total flow rate of the multiphase fluid is determined at least based on the measured differential pressures. In some cases, flow rates of each of the phases of the multiphase fluid can be determined at least based on the measured differential pressures.