Downhole Three-Phase Flow Measurement Using Sound Speed Measured by Local or Distributed Acoustic Sensing

In-well multiphase flow measurement continues to be a challenging task in the oil and gas industry. One promising technology to achieve this goal is the distributed acoustic sensing (DAS) system deployed downhole along a fiber. A DAS system is usually capable of measuring speed of sound (SoS) and, depending on the type of application and how the system is installed/configured, it may also measure flow velocity. In its current state, the DAS technology is still not fully explored in multiphase flow measurement for reasons including but not limited to the lack of flow algorithms and methodologies that can use measurements in a combinative and coherent approach. The current work introduces a game-changing methodology in applying the DAS and other sound measuring optical or electronic technologies to measure 3-phase flow. The 3-phase flow measurement methodology is based on the measurements of SoS at different locations along the well where the pressure is greater than the bubble-point pressure (P>Pb) at the first location and P