Measurement of Multiphase Flow of Oil and Gas Using Soft Sensor

This paper presents soft sensor as a multiphase flow meter. Nonlinear observer with Ensemble Kalman filter (EnKF) by Navier Stocks equations for inline flow is used to estimate the oil and gas flow. Finite element method and EnKF are used along two scenarios; in addition, in the first scenario, the estimation is done with the refinery output measurement; and in the second scenario, this estimation is done with the production unit output measurement. In this article, we don’t use primary element for multiphase flow measurement, instead of that flow will be estimated using some secondary variables (like pressure, temperature, output single phase flow, phase fraction and etc that can be measured directly with high accuracy). Results of comparison between two mentioned scenarios show that also the estimation with output measurement is not accurate, but the accuracy and repeatability of second scenario (estimation with production unit measurement) is in the acceptable standard range. Thus we can conclude that this soft sensor can be used as a backup for primary system and also as a primary system for multiphase flow measurement.