The Development Of Multiphase Flow Metering Equipment Based On Open Channel Flow

The measurement of multiphase flow is one of the most critical technologies which influence the development of oil industry in the future. This technology needn't separate each component of the multiphase flow, and can measure the flow rate of each component (oil, water and gas). So this technology can replace the traditional measurement system which is composed of test separator, single phase monitor instrument and manifold, and is very useful for flow process simplification and investment decrement of petroleum exploitation.Modified program about existing multiphase flow metering system was put forward based on the predecessor's studies. The principle of the modified metering system is that the metering models of liquid and gaseous phase are established based on the principle of mixed fluid's fluid dynamics in open channel, and then solved to get the preliminary flow rate of gas and liquid phase by means of these models. Results of models metering and the distilled eigenvalue of differential pressure of liquid level, tiny differential pressure of gas, pressure and other parameters are used as input of corresponding for gas-liquid two-phase measurement neural network. Based upon characteristics of numerical values, the neural network would perform quantitative analysis of flow feature by means of identification and classification of flow pattern, and then find out the functional relationship between correlation physical quantity and velocities of gas phase and liquid phase, further compensation and modification of the results would be made to obtain the final flow rate of gas and liquid phase.In order to validate the performance index of modified multiphase flow metering system, the detailed study has been done in laboratory and onsite experiment. The linear dependence of the collecting data has been quantitative analyzed in this thesis. According to the result of analyses, different characteristic parameters have been selected for different flow regime, and then the experimental data has been sorted, classified and calculated.'Interlace-overlap interval fitting'was adopted to realize the numerical value fitting to state parameter in treating process. Amelioration effectiveness of modified device structure and measurement routine have been contrastively analyzed with the before modified. Multiphase flow metering system was applied to onsite experiment. The results showed that the relative error of liquid phase flow rate is below 10% at a confidence level of 90%, the relative error of gas phase flow rate is below 15% at a confidence level of 90%, the relative error of water cut is less than 5%. The metering precision of this meter can approach or meet the need of oilfield multiphase flow metering.New modified program about the device in existence is put forward aiming at the shortages and flaws of multiphase flow metering system at field testing.