Prediction of Gas Field Gathering Pipeline Liquid Accumulation and Analysis of Influencing Factors

Abstract Gas field gathering pipeline connects the wellhead and processing station, wet gas gathering process is commonly used in this pipeline. During transportation, the liquid phase is tend to precipitate under low temperature and high pressure conditions, and gradually gather inside the pipeline. Liquid accumulation will reduce pipeline operation efficiency, clog the pipeline, and increase the corrosion rate, which will affect the safe operation of the pipeline. Accurate prediction of the amount and the serious area of liquid accumulation is of great significance for the safety and high efficiency of pipeline. In order to construct a gathering pipeline liquid accumulation prediction model, different saturated water content calculation models are compared to obtain the amount of precipitated liquid, different gas-liquid two-phase flow calculation formulas are compared to obtain the pressure drop and liquid holdup. The accuracy of the model is verified by combining gas field production data and simulation results. The changes of parameters such as pressure and liquid holding rate along the pipeline are analyzed. The influence law of inlet pressure and temperature on fluid accumulation is studied. The results show that the relative error of the calculation results of the liquid accumulation volume of the model is in the range of 1.82%∼5.56%. With the running time, the pressure and the amount of liquid accumulation along the pipeline gradually increase, and the amount of liquid accumulation reaches the maximum value after 243h, and the liquid accumulation is mainly distributed in the rising part of the low-lying pipeline section. The pipeline inlet pressure is directly proportional to the saturated liquid volume and discharge cycle, and inversely proportional to the saturated water precipitation rate. Pipeline inlet temperature is directly proportional to the saturated liquid volume and saturated water precipitation rate, and inversely proportional to the liquid discharge cycle. The prediction model of gas field gathering pipeline fluid accumulation established in this study is reliable and can provide scientific guidance for the prevention and control of pipeline fluid accumulation.