Benchmarking DAS Interrogator Performance for Flow Monitoring Applications: A Broadband Study with Mechanical, Acoustic, and Turbulent Flow Stimuli

This paper presents a systematic workflow to evaluate the performance of Distributed Acoustic Sensing (DAS) interrogators for flow monitoring applications under controlled laboratory conditions. Broadband responses are assessed using benchtop testbeds equipped with standard and engineered fiber-optic sensors, each subjected to meter- and sub-meter-scale stimuli that emulate downhole flow phenomena. The methodology incorporates four primary stimuli: mechanical waveform injection via calibrated piezoelectric actuators across a wide frequency and amplitude range; acoustic waveform injection using multiple modulation schemes to simulate non-contact sensing; flow-induced waveforms from turbulent gas flow to measure phase response and coherence; and thermal stimulation. To assess signal fidelity under realistic conditions, the setup integrates polarization controllers and axial translation modules that simulate disturbances typical of mobile conveyance systems such as wireline and coiled tubing. The results reveal that conventional testing protocols can be effectively complemented by additional benchtop tests utilizing diverse stimuli, supporting broadband performance validations essential for accurate flow monitoring applications. This comprehensive evaluation de-risks technology selection and helps unlock the full potential of DAS for complex in-well flow characterization.