气田生产中天然气水合物生成体系的实验研究

EXPERIMENT RESEARCH OF GENERATION SYSTEM OF GAS HYDRATE IN GAS FIELDS

气田生产中,特别是在试气、试采阶段常存在天然气水合物在井内管柱或地面管线中生成,堵塞井筒、管线、阀门和设备,从而影响天然气的开采、集输和加工的正常运转。在实际生产中,天然气水合物生成的液体体系十分复杂,其中包括电解质、凝析油和各种化学添加剂等,这些物质的存在对水合物生成条件和抑制剂的防治效果有很大影响。针对气田生产的实际情况,文章尽可能接近现场水合物生成体系,以某气田为例,利用JEFRI蓝宝石水合物装置,通过实验分别研究了含泡排剂、含电解质和含凝析油的天然气水合物生成液体体系,并与纯水体系进行对比,探讨了在这3个体系中天然气水合物形成的临界条件的变化以及对抑制剂抑制效果的影响,从而为水合物的现场防治提供了依据。

During gas-field exploitation, especially at gas test and production testing stages, it often happens the gas hydrate generated in the down-hole string or the ground pipelines blocks the borehole, pipelines, valves, and devices, which influences the normal operation of gas recovery, transportation and processing. In fact, the liquid system formed by gas hydrate is very complicated, which includes electrolyte, condensate oil, and different chemical additives etc. These substances affect the conditions of hydrate generation and the effects of hydrate inhibiter greatly. According to the real situation of gas-field exploitation, the hydrate generating system is simulated by the actual conditions as much as possible. Taking some gas field as example, with JEFRI sapphire hydrate device, the liquid systems of gas hydrate generating with frothing agent, electrolyte and condensate oil are studied by experiments and compared with the pure water system. The variation of critical conditions to form gas hydrate and its influence on the effects of inhibiter are discussed for the 3 hydrate systems, which provides the basis to prevent hydrate generation in the fields.