Four series of cement slurries were cured for a period of 14 days under high temperature and high pressure condition (200 °C, 20 MPa) to investigate the influences of different admixtures on the physical and mechanical properties of oil well cement. The admixtures studied include coarse and fine silica flour, silica fume, and various colloidal nanomaterials. The property of the cement formulation evaluated includes rheology, compressive strength, Young's modulus, water, and gas permeability, and X-ray diffraction profile. Test results reveal that the total silica dosage is the primary determining factor for the mechanical property of the set cement. Slurry TS60 with 60 % silica exhibits about 400 % increase in compressive strength and more than 1 order of magnitude reduction in permeability compared to slurry TS40 with 40 % silica. Lower strength and higher permeability of TS40 are associated with the formation of excessive xonotlite phase. The adoption of smaller sized silica (fine silica flour and silica fume) and various nanomaterials can serve to reduce the permeability of the set cement (by approximately 50 %), possibly through the well-known filler effect.

将四个系列的水泥浆在高温高压条件下（200℃，20MPa）固化14天，研究不同外加剂对油井水泥物理力学性能的影响。研究的外加剂包括粗和细的硅粉、硅粉和各种胶体纳米材料。评估的水泥配方的特性包括流变学、抗压强度、杨氏模量、水和气体渗透率以及 X 射线衍射图。试验结果表明，二氧化硅的总用量是水泥力学性能的主要决定因素。与含 40% 二氧化硅的浆料 TS40 相比，含 60% 二氧化硅的浆料 TS60 的抗压强度提高了约 400%，渗透率降低了 1 个数量级以上。TS40 较低的强度和较高的渗透率与过量硬硅钙石相的形成有关。采用较小尺寸的二氧化硅（细硅粉和硅粉）和各种纳米材料可用于降低凝固水泥的渗透性（约 50%），这可能是通过众所周知的填料效应。