Comparison of Transverse With Axial Excitation Modes Cross Correlation Flowmeters in High Water-Cut Oil-Water Flow Measurement

Due to long-term exploitation of oil wells, high water-cut oil-water two-phase flow has become one of the most common flow types in offshore oil fields. In this work, two cross correlation flowmeters for this type of flow, i.e., the newly proposed transverse excitation mode flowmeter and the conventional axial excitation mode flowmeter, are theoretically analyzed, numerically solved, and experimentally compared. By building theoretical models, the resolutions and sensitivities of the sensors are systematically compared to demonstrate their abilities to detect oil bubbles in water. From the numerical solutions by the finite-element method (FEM) models, the resolutions of the sensors are analyzed in the spatial frequency domain, and more accurate analysis of sensitivities can be made. Results show that the resolution of the transverse excitation mode flowmeter is approximately three times higher, and the sensitivity is at most 3.47 times higher than the axial excitation mode one. Experiments with 10m3/d, 90%-water-cut oil-water two-phase flow are carried out to demonstrate the dynamic performances of the two flowmeters. It can be concluded that the transverse excitation mode flowmeter has higher accuracy and reliability in flow rate measurement.