FLOW MONITORING

摘要

This application describes methods and apparatus for monitoring flow of fluids within conduits using fibre optic Distributed Acoustic Sensing (DAS). The method can determine flow rate and/or flow regime within a conduit such as within a production well or a pipeline. Embodiments involve introducing an acoustic stimulus (802) into the fluid within the conduit (801); interrogating an optical fibre (104) deployed along the path of the conduit to provide a DAS sensor; and analysing the acoustic signals detected by a plurality of channels of the DAS sensor to determine at least one flow characteristic. Analysing the acoustic signal comprises identifying reflections (804) of said acoustic stimulus caused by the fluid within the conduit and analysing said reflections to determine any Doppler shift (Deltaf).