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In the process of gas lift design and condition diagnosis, the accuracy and timeliness of wellbore multiphase flow model prediction results are the basis for all subsequent work. However, for the commonly used wellbore multiphase flow pressure drop prediction models, there is a big deviation between the predicted value and the measured one, and the optimization based on the measured data is time-consuming, and it is difficult to obtain the optimal parameters of the model. Therefore, based on the well bore pressure distribution data measured quickly in area R of an oil field in Kazakhstan, a better prediction model of multiphase flow in the well bore was selected at first. Then, the simultaneous perturbation stochastic approximation (SPSA) algorithm was incorporated in the wellbore multiphase flow model to optimize the liquid holdup, which is the leading factor in the model. After repeated single well optimization and greedy selection, the optimal parameters suitable for the whole block were obtained. The example shows that the optimization speed is 10 times faster than that of Particle Swarm Optimization (PSO). After that, the optimized model was used to predict the wellbore pressure distribution, and it was found that the relative error between the measured value and the predicted one was less than 15%. [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]