硅酸盐钻井液稳定井壁机理分析

以硅酸钾或硅酸钠为主要处理剂的硅酸盐钻井液体系近年来应用较多,该类体系具有很强的稳定井壁能力和环境相容性,其稳定井壁机理不同于其它常用水基泥浆体系。文中在介绍该类泥浆体系及应用情况基础上详细分析了其稳定井壁机理,认为有四个方面:①快速在近井壁堵塞孔隙和微缝,阻止滤液进入地层,减少压力穿透;②抑制页岩中粘土矿物水化;③硅酸盐和粘土矿物发生反应;④其它无机盐的协同稳定作用。

Borehole Stability Mechannisn of Silicate-Based Driling Fluids

Silicate-based drilling fluids with main additives being sodium or potassium silicate have been widely applied in recent years. The system shows strong borehole stability and environmental compatibility. Its stability mechanism differs from other water-based drilling fluids. After introducing the system, the borehole stability mechanism this paper is particularly analyzed .There are four aspects contributing the mechanism: (1) quickly plug pores and fractures near - wellbore, stop filtrate from entering formation and reduce pore pressure penetration; (2) constrain hydration of clay minerals in shale; (3) silicate reacts with clay minerals; (4)coordinate stability of other inorganic salts.