降低钻井液水眼粘度的室内研究

A LABORATORY STUDY ON“BIT NOSE VISCOSITY”OF NON-DISPERSED LOW SOLID DRILLING FLUIDS

利用 Casson 流变模式得到的钴井液的η_∞(习惯上称为水眼粘度)与钻进 V 直接相关.本文在室内研究了钻井液基础材料及30多种处理剂对低固相不分散聚合物钴井液η_∞的影响规律,为现场合理使用这种钻井液体系及降低水眼粘度提供了依据。

The value η_∞ determined from rheological measurements of drilling fluids using Casson's model is considered imaginarily as bit nose viscosity in some literature and is directly relat- ed to drilling penetration rate.In this work the effect of basic materials and more than 30 additives on η_∞ of non-dispersed low-solid drilling fluids is investigated experimentally in laboratory.The additives studied are viscosity-reducing,viscosifying,filter-loss-reducing, shale-inhibiting,coagulating,sticking-preventing and others.It is shown that①the η_∞ in- creases with increasing amount of bentonite of low yield in the drilling fluids;②the η_∞ tends to be lowered with adding bentonite of high yield in certain load range;③inorganic salts such as KCl and NaCl reduce the η_∞ of the drilling fluids;④organic additives with strong hydratable groups(such as -CONH_2) in molecular chain increase the η_∞ notably;⑤ except inorganic salts,all mud additives increase the η_∞ in different extent,and the more these additives the higher the η_∞ of the drilling fluids.The effect of temperature is also studied,