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Compared with experimental data of pressure drop of gas-liquid two-phase upward flow with low gas-liquid ratio in vertical pipe, the mean relative error of pressure drop predicted by Orkiszewski's model is 63.62%, the maximum relative error of the model is 98.07%. This paper first introduces the process of acquiring experimental data, then, combined with the experimental data, it is pointed out that the Orkiszewski's model has a small error in predicting the annular-mist flow pattern, but a large error in predicting the slug flow pattern and annular-slug transition flow pattern. The author analyzes the structure of Orkiszewski's model and points out that the formula of liquid distribution coefficient in slug flow pattern is complex and very important. In this paper, a new threshold value of liquid distribution coefficient is proposed and an improved Orkiszewski's model is obtained by particle swarm optimization. The calculated results of experimental data show that the average relative error of the new model is reduced to 25.28%, and the average relative error of the new model can be reduced from 76.17% to 17.21% for the slug flow pattern with continuous oil phase and total flow velocity greater than or equal to 3.048m/s. [ABSTRACT FROM AUTHOR]

To identify the accurate gas volume to carry liquid in horizontal gas well, this paper simulates the gas-liquid two-phase flow in a single pipe on the platform of multiphase pipe flow. Through indoor experiments on gas-liquid two-phase flow, it is confirmed that the inclined section (inclined angle: 45°~ 60°) is mostly likely to suffer from liquid loading in horizontal gas well. Then, a new critical liquid-carrying model was built after fitting the liquid holdup calculation formula at different inclined angles, considering the actual liquid-carrying phenomenon. The proposed model was proved accurate enough for engineering application through verification by indoor experiments. [ABSTRACT FROM AUTHOR]

In view of the limited conditions of the previous inclined multiphase pipe flow experiments (diameter and flow) with no reliable adaptability of multiphase pipe flow calculation method which is obtained from this experimental conditions when the using conditions are beyond the scope of the experiment (such as a middle to large diameter and large flow), the gas-liquid two-phase flow experiment was carried out using air and water as the medium with different inclined angles 0°, 15°, 30°. 45°, 60°, 75° and 90° in this paper. The analysis of variation of liquid holdup and pressure drop with different gas and liquid quantities and inclination angles was obtained. The calculation method applicability of liquid holdup and pressure drop were verified and selected from the experimental data, and the error variation law of the calculation methods w ere analysed. The applicability of the calculation method was compared with its applicability to liquid holdup and pressure drop as verified by the field test data. According to the analysis of the comparative results, the applicability conditions of the existing pressure calculation methods were obtained and they provided the guidance for the selection of the inclined multiphase pipe flow calculation methods under the condition of middle and high production rates. [ABSTRACT FROM AUTHOR]