天然气水合物钻井液冷却系统设计研究

摘要

天然气水合物钻井液冷却系统是天然气水合物钻井的关键技术装备之一,鉴于此,对天然气水合物钻井中钻井液冷却及温控系统进行了设计研究.系统整体采用模块化设计、一体化橇装结构,并采用闭式循环强制传热技术,系统核心部件换热器设计为人字形板式换热器,温度自动控制模块基于单片机进行设计.同时基于平均温差法完成换热器的热负荷和换热面积的理论计算.试验中系统能够实现钻井液冷却并在-4～4℃的范围之内动态恒温控制,能防止钻井液过冷冻结而堵塞换热器.设计的天然气水合物钻井液冷却系统可有效解决天然气水合物钻井中由于钻井液温度升高导致的井壁坍塌和天然气水合物分解的技术难题.%Natural gas hydrate drilling fluid cooling system is one of the key technical equipment for natural gas hydrate drilling.The drilling fluid cooling system and temperature control system for natural gas hydrate drilling have been designed.The whole system adopts modular design and integrated skid-mounted structure,and closed circulation forced heat transfer technology.The core component of the system was designed as a herringbone plate heat exchanger.The automatic temperature control module was designed based on MCU.The theoretical calculation of heat load and heat transfer area of heat exchanger is based on average temperature difference method.In the test,the system can realize the drilling fluid cooling and dynamic temperature control in the range of-4 ～ 4 ℃,and can prevent the drilling fluid from freezing and blocking the heat exchanger.The designed natural gas hydrate drilling fluid cooling system can effectively address the technical issues of wellbore collapse and the decomposition of the natural gas hydrate due to the increase of the drilling fluid temperature in the natural gas hydrate drilling.