For single phase flow meters more and better non-intrusive or even clamp-on meters become available. This allows for a wider use of meters and for easier flow control. As the demand for multiphase meters is increasing, the current aim is to develop a nonintrusive multiphase flow meter. The non-intrusive techniques ideally must use simpler technologies used in multiphase flow meters already present on the market. This simplification reduces capital and operation expenditures of the flow meter an end used has to incur. The technology for a multiphase flow meter proposed here, is based on nonintrusive soft-sensing techniques to extract signals generated by a multiphase flow. Outer pipe wall accelerations are measured at different positions by simple non-intrusive accelerometers. The accelerometers generate a signal from which characteristic multiphase flow parameters are extracted. For instance, in case of intermittent flows, slug velocity and slug frequency are reconstructed. These parameters are subsequently used in semi-empirical models. The models relate the parameters with flow rates of gas and liquid - operation parameters we are looking for. The algorithm for signal processing and analysis results in a good estimation of the liquid and the gas flow rates. In a certain range of GVF (gas volume fraction) the estimation results in flow rate measurement at commercially accepted accuracy.
An important asset of the described construction of the multiphase flow meter is its simplicity. The simplicity extends applicability of the flow meter which can be used in oil wells, flow lines as well as in process installations. The current activities aim at further validating the models and on extending the applicability range to other gas-liquid ratios.