Study On Influencing Factors Of Three-phase Flowmeter Accuracy And Structure Optimization

The three-phase flowmeter can measure the data of important parameters such aswater content, gas fraction, crude oil output and natural gas production out of the oilwell products, which can provide analysis data to optimize the production parametersand improve oilfield output. Due to its high-degree automation, compact structure andlow cost, the three-phase flowmeter has been gradually recognized as the preferredmeasuring equipment by major oilfields at home and abroad. As the accuracy ofthree-phase flowmeter measurement strongly affects the optimization of productionparameters, it is necessary to analyze the facters which influence the measurementaccuracy.In order to improve the accuracy of water content measurement of three-phase flowmeter, the thesis proposes a solution of measuring the water content of produced fluidsof oil well by densimetry and measuring the total density of produced fluids of oil wellby weighing measurement.According to the mathematical model which is created from the principle ofdensimetry, the thesis analyzes the effects of height measurement accuracy anddifferential pressure measurement precision on water content measurement errors, and itworks out the needed test index which meets the standard requirements. Meanwhile,another mathematical model which is created based on the principle of jet mechanicstheory shows the height of bubble layer caused by the impinging jet during thefliud-filled process. The thesis not only makes a theoretical research on how the bubblesaffect the accuracy of water content measurement, but also analyzes all the importantinfluences and improvements of the original solution to meets the requirements of newtargets.The thesis estabilishes two finite element models respectively based on the originalsolution and the new solution. By making a simulation analysis on the air entrainmentof both finite element models through the VOF model of FLUENT, it works out thedegree of importance of each factor and the optimal value. As the results of originalsolution are still unable to meet the required accuracy, the new one with results betterthan the target requirements is necessary and feasible.