RESUMO
Flow parameters measurement facilitates the understanding of two-phase flow. Due to the changeable structures of the flow, the prediction of superficial velocity of oil-water two-phase flow in large diameter pipes is still a challenging problem. Therefore, we first conducted a vertical upward oil-water two-phase flow experiment in a 125 mm ID pipe, and obtained the response signals under different flow conditions by a vertical multi-electrode array (VMEA) conductance sensor. Then, new data pre-processing (1D to 2D) techniques and information fusion techniques (network channels) are employed. Moreover, the front-end structure of the network is optimized using a combination of attention block and residual structure, and the middle structure is optimized using inception block; on the other hand, the back-end structure of the original capsule network is innovatively changed so that it can handle both the flow pattern classification and superficial velocity prediction tasks. The dynamic routing algorithm has also been improved to speed up model training. Extensive experiments validate the effectiveness of the improved modules. Finally, we compare the proposed network with its variants and other competing networks. The better performance results show that our multi-task sequence-based CapsNet has great potential for dealing with high-dimensional, time-varying and nonlinear problems in multiphase flow.
RESUMO
In oil-gas-water three-phase flow, the presence of two physically distinct dispersed phases leads to complex interfacial effects and relative velocities between the phases, which poses a significant challenges for gas holdup measurements. In this paper, a novel gas holdup measurement based on flow structure detection is realized. Firstly, the effect of gas bubble diameter on ultrasonic attenuation was studied, and a gas bubble diameter-based ultrasonic gas holdup measurement model was proposed. According to the model's specifications, a combined measurement system consisting of pulse transmission ultrasonic sensor and bi-optical fiber probe sensor was built. The dynamic experiment of oil-gas-water three-phase flow was conducted on a simulated well installation to measure the gas holdup using the combined measurement system. The results suggest that the proposed ultrasonic-optical measurement system can attain a high level of measuring precision.
RESUMO
Oil-water two-phase flows widely exist in industrial production, especially in the petroleum industry. The liquid holdup is significant for understanding reservoir production characteristics and improving oil recovery. This paper focuses on the helical capacitance sensor for the measurement of water holdup of oil-water two-phase flows. A new double helix capacitance sensor with an electrode rotation angle of 360° is designed. The sensitivity field distribution of the sensor with different parameters is simulated by the finite element analysis method, and the optimal geometric size of the sensor is obtained. The measurement characteristics of the sensor under different flow conditions are investigated by dynamical experiments of vertical oil-water flows. By analyzing the response signal of the helical capacitance sensor, the flow pattern can be identified, and the apparent water holdup can be calculated. The results show that the proposed sensor is suitable to measure the water holdup in a wide range of water cuts. Even in flow conditions of a high water cut, the sensor still retains good resolution in the D O/W flow pattern. This study expands the water holdup measurement of a capacitance sensor in the case of an oil-water two-phase flow with a high water cut.
RESUMO
The complex flow structure and interfacial effect in oil-gas-water three-phase flow have made the void fraction measurement a challenging problem. This paper reports on the void fraction measurement of oil-gas-water three-phase flow using a mutually perpendicular ultrasonic sensor (MPUS). Two pairs of ultrasonic probes are installed on the same pipe section to measure the void fraction. With the aid of the finite element method, we first optimize the emission frequency and geometry parameters of MPUS through examining its sensitivity field distribution. Afterward, the oil-gas-water three-phase flow experiment was carried out in a vertical upward pipe with a diameter of 20 mm to investigate the responses of MPUS. Then, the void fraction prediction models associated with flow patterns (bubble flow, slug flow, and churn flow) were established. Compared to the quick closing valves, MPUS obtained a favorable accuracy for void fraction measurement with absolute average percentage error equaling 8.983%, which indicates that MPUS can satisfactorily measure the void fraction of oil-gas-water three-phase flow.
