Characterization of Gas-Liquid Two-Phase Slug Flow Using Distributed Acoustic Sensing in Horizontal Pipes

Area of Science:

• Engineering
• Physics
• Materials Science

Background:

• Gas-liquid two-phase slug flow is prevalent in industries like oil and gas, posing operational challenges.
• Traditional multiphase flow sensors are often intrusive, costly, and limited in harsh environments.
• Accurate, real-time monitoring of slug flow is critical for process optimization and safety.

Purpose of the Study:

• To investigate the application of distributed acoustic sensing (DAS) for quantitative monitoring of gas-liquid two-phase slug flow.
• To develop and validate new algorithms for characterizing slug flow dynamics using DAS data.
• To assess the advantages of DAS over conventional methods for multiphase flow measurement.

Main Methods:

• Experiments were conducted using a transparent pipe with a helically wrapped fiber optic cable connected to a DAS integrator.
• Mineral oil and compressed air were used to simulate various gas-liquid flow conditions.
• New algorithms were developed to analyze DAS signals for slug frequency, velocity, and length measurements.
• High-speed camera validation was performed to ensure measurement accuracy.

Main Results:

• DAS successfully captured and characterized various slug flow regimes under different flow rates and gas-oil ratios.
• Developed algorithms accurately determined slug frequency, translational velocity, slug body length, slug unit length, and liquid film region.
• Measurements from DAS showed good correlation with high-speed camera validation data.
• New metrics for slug flow characterization, such as liquid film region length, were successfully derived from DAS data.

Conclusions:

• Distributed acoustic sensing (DAS) provides a non-intrusive, continuous, and real-time method for monitoring gas-liquid slug flow.
• The developed algorithms enable quantitative characterization of slug flow dynamics, including novel parameters.
• DAS technology presents a cost-effective and robust solution for multiphase flow monitoring in challenging industrial environments.
• This approach offers significant potential for optimizing facility design, operation, and ensuring safer practices in industries affected by slug flow.