氮气钻井因其独特优势，成为开发致密砂岩气藏有效的方式之一。钻井中地层出水风险，会限制氮气钻井技术的规模化应用，因此，如何准确预测或监测地层出水，成为氮气钻井发展的“卡脖子”技术。综合考虑地层产气与出水，耦合井筒压力场、温度场，建立全井筒相对湿度分布模型并进行数值求解，结合氮气钻井随钻监测系统，实现对井下压力、温度及湿度等重点参数快速定量评价。在川西DY105井须家河组氮气钻井施工中对地层出水工况进行判断，指导现场施工。所建相对湿度分布模型对保障致密砂岩有水气藏储层氮气钻井安全施工具有重要意义。

Nitrogen drilling is one of the effective ways to develop tight sandstone gas reservoir because of its unique advantages. The risk of formation water production in drilling will limit the large-scale application of nitrogen drilling technology, so how to accurately predict or monitor formation water production has become a "choke" technology in the development of nitrogen drilling. Comprehensively considering gas production and water production, coupled with wellbore pressure field and temperature field, the model of relative humidity distribution in the whole wellbore was established and numerically solved, it realized the fast quantitative evaluation of key parameters such as downhole pressure, temperature and humidity. During nitrogen drilling in DY105 well of Xujiahe in western Sichuan, the water-out condition of formation was judged to guide on-site construction. The established relative humidity distribution mode is of great significance to ensure the safe operation of nitrogen drilling in tight sandstone water-bearing gas reservoir.