低温微细低密度水泥的实验研究

实验研究了低温条件下微细水泥在低密度水泥浆中的应用。结果表明，在低温条件下，与常规水泥相比，采用微细水泥可以大大提高低密度水泥的早期强度。微细水泥用于低密度水泥体系中,因为水泥越细,水泥的表面积就较大,水能很快地渗入水泥内部,其表面积增大也提高水化反应的速度,从而解决常规低密度水泥早期强度偏低的问题。低密度体系中的稳定性、渗透性也得到了较好的改善。微细低密度体系的静切力较高、触变性较好。另外，与常规水泥相比，微细水泥的初、终凝时间也有缩短，这对提高低密度水泥体系的防窜能力也是有利的。微细水泥在低温、低密度体系中对水泥浆的其它性能无不良影响，只要适当调节其稠化时间，即可满足固井施工的需要。

EXPERIMENTAL STUDY ON LOW TEMPERATURE FINE CEMENT WITH LOW DENSITY 1)

The article mainly studies the application of fine cement to the cement slurry with low density under the conditions of low temperature. The experimental study indicates under the conditions of low temperature, comparing with the conventional cements, it can greatly improve the early strength of the cement with low density to use fine cement. When the fine cement is used for the slurry system with low density, the problem, i.e. the early strength of the conventional slurry system with low density is low, is solved since the finer the cement is, the larger the surface area of the cement is, the faster the water percolating into the cement, and the quicker the hydration reaction. Also the stability and permeability of the slurry system with low density are well improved. The fine cement slurry with low density has higher shear strength and better rheopecticity. Comparing with conventional cement, the primary and final setting times of the fine cement are shorter, which is favorable to improve the anti-channeling ability of the cement slurry system with low density. No negative influence of the fine cement appears on the other properties of the slurry in the system with low temperature and low density. Only if its thickening time is adjusted properly, the requirements of the cementing operation can be met.