纳米基复合增强剂的研究与性能评价

Study and Evaluation of a Nano Compound Strength Enhancer

低密度水泥浆体系常面临水泥石强度低、顶部强度发展缓慢的问题,而常规促凝早强材料虽可增加水泥石强度,但多会明显缩短稠化时间,稠化时间和强度之间矛盾突出。针对该问题,通过引入表面改性的纳米材料,搭配高效激活材料,开发出了一种“弱促凝、高早强”型复合增强剂。针对不同低密度水泥浆体系,通过控制增强剂加量、温度、水灰比、密度等变量,对该剂进行了评价实验。结果表明,纳米基复合增强剂可在对稠化时间影响较小的前提下,大幅提高水泥石的抗压强度,其中低密度水泥石顶部强度提高率可达40%以上,在不同类型低密度水泥浆体系中均有提强效果,并在长庆油田进行了应用,效果良好。

Set cement from a low-density cement slurry has low strength and slow hardness development at the top of the cement slurry.Regular accelerating early strength materials,though can be used to enhance the strength of the set cement,will obviously shorten the thickening time of the cement slurry,hence reducing the strength of the set cement.To solve this problem,a“weak accelerating high early strength”compound strength enhancer was developed with a surface modified nano material and some high efficiency activators.The strength enhancer was evaluated in different low-density cement slurries by controlling the concentration of the strength enhancer,temperature,water/cement ratio and density.It was found in the evaluation experiments that the strength enhancer can greatly increase the compressive strength of the set cement,with only minor effect on the thickening time of the cement slurry.In these experiments,the percent strength increase of the top of the low-density cement slurry can be 40%or higher.The nano compound strength enhancer can be used in different low-density cement slurries to improve the compressive strength of the set cement.Application of this strength enhancer in Changqing Oilfield has proved its good performance.