高温堵漏剂的微观结构与堵漏机理

Microstructure and Sealing Mechanism of High-temperature Sealant

利用XRD、TG和SEM-EDS对XAN-RC高温堵漏剂在模拟实际作业环境的高温高压条件下水化的水化产物和硬化浆体微观结构进行了分析,对其高温堵漏机理进行了讨论。在高温高压条件下,除普通的硅酸盐水泥的水化反应外,XAN-RC高温堵漏剂中还存在硅质或硅铝质抗高温添加剂与硅酸盐水泥水化生成的Ca(OH)2之间的二次水化反应。初始水化生成的水化硅酸钙凝胶并不能转化为纤维状晶体;只有二次水化反应才能生成纤维状晶体,从而形成致密浆体,大幅度提高其高温粘结强度。

The hydration products and microstructure of hardened paste of XAN-RC high-temperature sealant were investigated using XRD, TG and SEM-EDS under the condition of high temperature and high pressure. Its sealing mechanism under the condition of high temperature was discussed. Under the condition of high temperature and high pressure, there is a secondary hydration reaction between silicosis or alumosilicate composition in XAN-RC sealant and Ca（OH）2 besides the initial hydration reaction of Portland cement. The CSH gel formed in the initial hydration process of Portland cement can not transforms to the fibrous crystal during the curing period of high temperature and high pressure, The fibrous CSH crystal can be yielded only through the secondary hydration reaction, which enhances the formation of a dense paste structure. As a result, the high temperature adhesive strength of XAN-RC sealant increases obviously.