钻井液专用智能纳米粒子的设计、制备及封堵机理研究

At present, when water-based drilling fluids are used in the drilling process of shale formations, nanoparticles should be added for plugging the borehole and preventing the infiltration of water molecules. However, these nanoparticles could not disperse stably and prevent water effectively. In the present project, smart nanoparticles will be prepared by selecting smart polymers modified the surface through surface chemical modification. These smart nanoparticles could be dispersed stably in water-based drilling fluids and could be used as a plugging agent and chemical inhibitor at the same time. The interaction rules between smart nanoparticles and the component of water-based drilling fluids will be studied in detail. And the plugging mechanisms of the smart nanoparticles added in water-based drilling fluids will be investigated more clearly. The research of present project will provide foundation for the preparation of high-performance water-based drilling fluids. And several innovative ideas and methods about wellbore stability and storage protection of shale formation will be provided.

目前，采用水基钻井液对泥页岩地层钻进时，需要添加纳米粒子对井壁孔隙进行封堵，以阻止水分子的渗透，但是单组份的纳米粒子分散稳定性较差，阻水效果也有限。本课题提出将智能高分子通过表面化学修饰的方法，修饰到纳米粒子表面，制备在水基钻井液中长期稳定分散，并且兼具物理封堵和化学抑制性能的智能纳米粒子。研究智能纳米粒子与钻井液组份的相互作用规律，系统考察智能纳米粒子的阻水性能，并理清其封堵机理。本课题的研究为高性能水基钻井液的制备奠定基础，为泥页岩地层的井壁稳定和储藏保护，提供新的思路和方法。

在页岩气开发钻井过程中，用水基钻井液钻井时，极易吸水膨胀，造成井壁坍塌等钻井事故。泥页岩地层孔隙处于纳米尺度，要防止泥页岩吸水膨胀，最有效方法之一是对泥页岩井壁的微小孔隙进行致密封堵，防止钻井液的滤失。常规封堵剂尺寸处于毫米、微米尺寸，远大于泥页岩地层孔隙尺寸，不能对其进行有效封堵。本项目研究适用于泥页岩地层的纳米封堵剂，详细探索了聚丙烯酸修饰的SiO2纳米粒子、聚对苯乙烯磺酸钠修饰的SiO2纳米粒子、聚2-丙烯酰胺基-2-甲基丙磺酸修饰SiO2纳米粒子、聚N-异丙基-丙烯酰胺修饰SiO2纳米粒子、聚甲基丙烯酰氧乙基三甲基氯化铵修饰的SiO2纳米粒子等纳米粒子体系，考察了纳米粒子的耐盐性能，耐高温性能，以及与钻井液常用处理剂的配伍性能，并通过模拟泥饼研究了这些纳米粒子的微纳米封堵性能和封堵机理。项目的研究成果对纳米粒子改性的水基钻井液体系的研究，奠定重要的研究基础，为适用于泥页岩地层的水基钻井液的开发，提供了重要的技术支持。