正电泥浆体系的研究 Ⅳ.高岭土正电泥浆体系

STUDIES ON CATIONIC MUD SYSTEMS (Ⅳ) POSITIVE KAOLINITE MUD SYSTEMS

研究了高岭土-混合金属层状氢氧化物(MMH)体系的ξ电位、流变学及滤失量等性质,发现MMH在浓度很低时即可将体系转化成正电体系。MMH对高岭土泥浆有分散、稳定作用,可使体系由非牛顿流体转化为牛顿流体。传统的降滤失剂均对高岭土-MMH泥浆有降滤失作用,但同时使体系的ξ电位降低。

The zeta potential, Theological properties,and filtration loss of kaolinite-MMH mud systems are studied.It is found that a kaolinite-MMH system can be transformed from negative into positive at very low MMH concentration, some 0.2% for a 10% kaolinite mud.MMH reduces apparent viscosity(AV)and filtration loss(FL)of positive kaolinite muds and serves as dispersant/stabilizer for them.A kaolinite mud with 0.5% MMH appears to be plastic fluid and with 1% MMH-Newtonian,structure-free fluid. At concentration of MMH 1% and higher AV, plastic viscosity and yield stress cease to decrease abruptly and FL gradually reduces and levels out, with zeta potential changing accordingly. Traditional FL controllers in 1-2% and more can reduce FL value of positive kaolinite-MMH muds to an acceptable level but lead to decreasing zeta potential,transforming them into negative ones.The more the negative charge of the mud additives is, the more zeta potential of the mud decreases. For these positive mud systems special nonionic and cationic additives are necessary.