泡排技术清除起伏管道积液试验

Experimental study on foam drainage technology for removal of liquid accumulation in pipelines with undulating profiles

【目的】受起伏地形的影响,湿天然气集输及油气混输管道易在沿程起伏及低洼处形成积液。由于起伏集输管道与垂直气井在倾角方面存在巨大差异,作为气井清除积液的成熟方式,泡沫排液技术无法直接应用于混输管道排液,其可行性需进一步论证。【方法】利用气液多相管流试验环路,通过管流试验探究不同倾角条件下泡沫对气液多相流流动特性的影响,并明确含泡沫多相流的起塞作用机制;基于无机盐改变泡沫体系性能,探究泡沫性能变化对含泡沫多相流动特征产生影响的原因,并分析含不同流动状态下流动特征参数与压力差压的特征。【结果】在与气井倾角差异较大的低起伏管道中,可通过添加表面活性剂的方式清除积液,并对段塞流工况的发生起到较好的抑制作用;通过在SDS(Sodium Dodecyl Sulfate)表面活性剂溶液中添加NaCl、MgCl2作为环境影响因素,利用金属网格传感器、高速摄像系统以及压力传感器,进一步探究无机盐条件下SDS水基泡沫排液效果,发现无机盐引起的泡沫性能差异会对泡沫排液效果产生较大影响;当管道内出现过量稳定泡沫时,会引起管道沿程压降显著增大。【结论】将泡沫排液技术应用于有积液的集输管道排液时,稳定性是选择合适泡沫体系的关键指标之一,且泡沫层对管内介质流动特性的影响与泡沫体系性能之间的联系是今后研究的重点方向。(图14,参31)

[Objective] Pipelines with undulating profiles are susceptible to liquid accumulation at low-lying positions along their route,particularly when utilized for gathering and transmission of wet natural gas and transmission of oil-gas blends.Considering the significant difference in inclination angle between gathering and transmission pipelines and gas wells,foam drainage technology,already wellestablished for the removal of liquid accumulation from gas wells,needs to be further demonstrated before its application to transmission pipelines carrying oil-gas blends.[Methods] Gas-liquid multiphase pipe flow experiments were conducted using an experimental loop setup,aimed at investigating the impact of foam on the characteristics of gas-liquid multiphase flow at various inclination angles and elucidating the mechanism of plug formation in foam-containing multiphase flow.Additionally,the study examined the impact of changes in foam system properties induced by the presence of inorganic salts on the characteristics of foam-containing multiphase flow.Flow regime-specific analysis was conducted on flow characteristic parameters and pressure difference features.[Results] In pipelines with undulating profiles and significantly different inclination angles compared to gas wells,the addition of surfactant was found effective in removing accumulated liquid and mitigating the occurrence of sectional slugged flow conditions.To investigate the drainage effect of water-based Sodium Dodecyl Sulfate(SDS) foam under the influence of inorganic salts,a further study was conducted with the presence of NaCl and MgCl2 as environmental impact factors,and using metal grid sensors,a high-speed camera system,and pressure sensors.The findings revealed that the variation in foam properties resulting from the effect of inorganic salts had a substantial impact on the efficiency of foam drainage.Furthermore,it was observed that an excessive formation of stable foam within the pipeline caused a substantial increase in pressure drop along the route.[Conclusion] When applying foam drainage technology to gathering and transmission pipelines with liquid accumulation,stability becomes a critical factor in selecting an appropriate foam system.Further research should focus on investigating the relationship between the influence of the foam layer on the flow characteristics of the medium in pipelines and the overall performance of the foam system.(14 Figures,31 References)