碳酸钙晶须增强油井水泥石的力学性能

Mechanics Performance of Oil Cement Paste Reinforced by Calcium Carbonate Whisker

李兴奎 庄稼

LI Xingkui ZHUANG Jia

本文采用碳酸钙晶须对固井水泥进行了改性，探讨了碳酸钙晶须对泥浆体以及硬化后水泥石的力学性能的影响，并分析了作用机理。研究结果表明：在水灰比0.44的情况下，加入碳酸钙晶须后水泥浆流动度降低，因而须加入高效分散剂、合理控制碳酸钙晶须加量和水灰比、优选外加剂体系；加入10% 的碳酸钙晶须后水泥浆的初始稠度由16.4 bc 增至34.6 bc 、稠化时间（70bc ）由311min缩短至160 min、API 失水量也明显降低；加入少量（0.5%）的缓凝剂HN- 22可有效控制稠化时间。在加量为10% 时，碳酸钙晶须改性水泥石的抗压强度、抗折强度以及劈裂抗拉强度与纯水泥石的相比分别提高10% ，54% 和28% ，表明碳酸钙晶须具有显著地增强作用。此外，通过界面层物理模型和X 射线衍射分析探讨了碳酸钙晶须增强水泥石的增韧机制。图11 表4 参15

Calcium carbonate whisker（CCW）was used to modify the properties of the oil cement system, and the influence of CCW on both cementing slurry and cement paste was preliminary tested. The results showed that, at water cement ratio of 0.44, the fluidity of the slurry containing CCW decreased, thus, the slurry dispersing agent should be added and optimized, and the water cement ratio and the dosage of the CCW also should be controlled. Compared to the blank slurry the initial consistency of the slurry containing 10% CCW increased from 16.4 bc to34.6 bc and the thickening time （70bc ）decreased from 311 min to 160 min, the API filtrate loss also decreased significantly. The thickening time of the cement slurry could be well controlled by using0.5% retarder HN- 22. The compressing strength, flexure strength and splitting tensile strength of the cement paste with 10% CCW increased by 10%,54% and28% ,respectively, compared to that of the blank sample, which indicating that the cement paste with the CCW had the strong toughing effect. In addition, the enhancement mechanism of the cement pastes with CCW was analyzed by the means of establishing a surface physical model and XRD measurements.