龙岗酸性气田低流速管道流动特征

针对龙岗酸性气田某些集输管道内积液和腐蚀严重的问题，基于气井采出流体的性质及输气管道基本运行参数，采用OLGA软件模拟两条典型的低流速管道及不同流量下的001—6#采气管道，分析两条管道内的流型、持液率以及流体与管壁间的剪切力沿管道的变化规律，研究流量对001—6#采气管道内各流动特征参数的影响规律。结果表明：OLGA软件模拟两条采气管道的压降和温降与实际生产数据一致，其模拟结果可靠；下坡管内持液率小于0．05，流体与管壁间的剪切力小于20Pa，上坡管内持液率为0．3～0．4，液相一管壁最大剪切力为80-270Pa，上坡管段是积液和腐蚀严重的区域；气体流量对龙岗001—6#低流速采气管道的流动特征参数影响很大，进一步减小气体流量会使上坡管内持液率及液体一管壁剪切力急剧增大，从而加剧管内积液和腐蚀；当气体流量增大至97．5×10^4m^3／d时，管内的持液率和管壁剪切力均很低，管内积液和腐蚀问题有所缓解。（表6，图6，参9）

Flow characteristic of pipeline with low flowrate in Longgang Sour Gasfield

In view of liquid deposit and corrosion in some gathering pipelines in the Longgang Sour Gasfield, OLGA software was used to simulate two typical low flowrate pipelines and 001-6# gas production pipeline under different flow conditions to analyze the flow pattern, liquid holdup and variation in shear stress between fluid and pipe wall along the pipeline and study how flow will influence fluid characteristic parameters in 001-6~ gas production pipeline. The results show that the pressure drop and temperature drop of the two gas production pipelines simulated by OLGA software are consistent with the actual production data, which means that the result of simulation is reliable. In the downhill pipelines, liquid holdup is less than 0.05 and shear stress between fluid and pipe wall is less than 20 Pa, while in the uphill pipelines, liquid holdup is from 0.3 to 0.4 and the maximum shear stress between fluid and pipe wall is from 80 to 270 Pa, which indicates that liquid deposit and corrosion are especially serious in the uphill pipelines. Flow of gas has a great impact on the fluid characteristic parameters in Longgang 001-6# gas production pipeline with low flowrate, further reduction of gas flow will cause drastic increase in liquid holdup and shear stress between fluid and pipe wall, which then will aggravate liquid deposit and corrosion. When the gas flow increases to 97.5×10^4m^3/d, the liquid holdup and shear stress between fluid and pipe wall are both very low, and the liquid deposit and corrosion will be relieved. （6 Tables, 6 Figures, 9 References）