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 97.5×10⁴ m³/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.