基于PVM的可视化水合物生成实验

Visually Experimental Study of Hydrate Formation Based on PVM

借助粒子视频显微镜(Particle Video Microscope,PVM)对水合物高压实验环路中的油包水乳状液混合以及水合物的生成、聚结过程进行了实验研究。结果表明:PVM设备可以清晰、定量、视觉化地检测到水合物的生成结晶过程以及实时颗粒/液滴的粒径分布,并发现随着水合物的不断生成,其水合物颗粒会发生聚结,形成较大的水合物颗粒,随着反应的进一步进行,水合物颗粒粒径会表现为先增大后减小的趋势,这主要是由于水合物生成过程中的颗粒、液滴间的碰撞、聚集使得粒径增大,同时体系中增强的剪切作用和水合物颗粒表面润湿性的减小致使聚集的水合物颗粒又发生破碎所致;再则,实验过程中阻聚剂的加入对油水乳状液具有较好的乳化作用,使其水相较为均匀的分散到连续油相中,形成稳定、均一的乳状液体系,并且其分散相水滴的粒径要较不加剂情况下少;在水合物的形成过程中水合物颗粒间的聚并是导致水合物堵塞管道的主要原因。

With the further development of offshore oil exploration, the threat of gas hydrate produced in submarine pipeline draws more and more attention. Therefore, Multiphase Flow Research Group of China University of Petroleum （Belling） investigated visually the process of oil-in-water emulsion mix and hydrate formation and coalescence in the high-pressure experiments loop by means of particle video microscope （PVM）. Morphologieal characteristic and distribution of particle/droplet in the above process were obtained, then quantitatively assessed the plugging risk in the hydrate formation process from the mieroseopie point. Experinlental results showed that PVM can clearly, quantitatively and visually detected the process of hydrate crystallization and the distribution of particle/droplet size real-time; the polymerization inhibitor in emulsion had good emulsification, which made the disperse phase dispersed into the continuous phase uniformly and formed a stable, homogeneous emulsion system; the phenomenon of coalescence and hroken between the hydrate particles occurred during the hydrate formation process, which was the main reason of plugging in the pipeline.