Abstract: The effect of the drilling fluid components on sag performance was studied. Experimental results show that the type of base oil, oilwater ratio, type of internal phase, particle size and type of weighting material have great effect on the sag stability of the system. The greater the viscosity of the base fluid, the lower the oilwater ratio, the better the sag performance is. The oilbased drilling fluid system with NH4Ca(NO₃)₃ as the internal phase shows better sag stability after static aging than the system with other internal phase such as formate, calcium chloride and sodium chloride. The smaller the particle size, the better the sag stability is. The oilbased drilling fluid system with Mn₃O₄ as the weigh material shows the best settling stability under static and shear conditions.

Key words: Oilbased drilling fluid,     ,  Sag stability,    ,  Base oil,    , Oilwater ratio,    ,  Internal phase,    ,  Weigh materials

摘要： 研究了油基钻井液组分对其沉降稳定性能的影响。结果表明, 基液类型、 油水体积比、 内相盐种类、加重材料粒径大小和种类会对油基钻井液的沉降稳定性能产生影响。静态沉降条件下基液黏度越大, 体系油水体积比越小, 体系沉降稳定性能越好。以 NH₄C a ( NO₃) ₃ 为内相的油基钻井液体系沉降稳定性能优于甲酸盐、 氯化钙和氯化钠内相钻井液体系。加重材料颗粒的粒径越小, 沉降稳定性能越好, 动态剪切和静态沉降条件下 Mn ₃O₄ 为加重材料的油基钻井液沉降稳定性能都优于其他加重材料体系。

关键词: 油基钻井液,    ,  沉降稳定性能,    ,  , 基液,    ,  油水体积比,    ,  内相,    ,  , 加重材料