多年来,在水基钻井液中使用硬沥青(Gilsonite)和其它沥青类产品作为帮助井眼稳定的添加剂。许多资料证明在含有水敏、塌落页岩的地层中,这些添加剂能够使井眼坍塌减至最低限度。井眼不稳定性的原因很多,在性质上有机械的、化学的或物理的。机械问题包括高环状空间返流速度的井眼冲蚀,高环状空间压力引起的反液压应力,因过厚的泥皮造成高抽吸和 For many years, Gilsonite and other bitumen products have been used in water-based drilling fluids as additives to help stabilize the borehole. Numerous data demonstrate that these additives can minimize wellbore collapse in formations containing water-sensitive, collapsed shales. Wellbore instability is due to many reasons, mechanical, chemical or physical in nature. Mechanical problems include wellbore erosion at high annulus velocity, back-hydraulic stress due to high annular space pressure, high suction due to thick mud