Abstract: Slag mud-to-cement(MTC) technique has been used in drilling engineering.The composition and hydration of slag MTC,and constituent of bentonite were studied by using X-ray diffraction.According to the theories of silicate chemistry and inorganic material chemistry,the hydration mechanism of slag MTC was analyzed.The slag is composed of large amounts of vitreum and minor cement clinker crystal.The bentonite is composed of sodium montmorillonite and quartz,which makes it similar to vitreum and can be activated under strong caustic conditions.Tricalcium silicate,dicalcium silicate and rankinite can be hydrated to get calcium silicate gel and calcium hydroxide.The activation of tricalcium silicate,dicalcium silicate and rankinite would be reduced with the decreasing of the calcium to silicon ratio.The calcium silicate gel has different calcium to silicon ratio.Hydrated product Ca(OH)₂ can be taken as an activator and react with SiO₂ to get C-S-H gel with a low ratio of calcium to silicon.The hydration of clinker in slag MTC is identical to its hydration performance of clinker in cement in 24 hours.

Key words: slag, mud-to-cement(MTC) technique, hydration mechanism, X-ray diffraction(XRD), C-S-H gel, well cementation

摘要： 针对钻井行业中采用矿渣MTC进行油气井固井的特点,利用XRD对矿渣MTC水化过程产物以及膨润土等进行了物相鉴定实验研究,根据硅酸盐化学理论、无机材料化学理论,分析了矿渣MTC的水化机理.研究结果表明:矿渣由大量玻璃体和少量水泥熟料晶体组成,膨润土中含有大量的钠蒙脱石和石英,使其与玻璃体的性能相似,可以在强碱作用下被激活.硅酸三钙、硅酸二钙、硅钙石等都可以水化生成硅酸钙凝胶和Ca(OH)₂,随着钙硅比的减小,它们的活性减弱,并且生成的硅酸钙凝胶也具有不同的钙硅比.反应过程的水化产物Ca(OH)₂可以作为矿渣的激活剂,与SiO₂作用生成低钙硅比的C-S-H凝胶,其中水泥熟料物质的水化进程与其在24h之内的水化特性相吻合.

关键词: 矿渣, 泥浆转化为水泥浆技术, 水化机理, X射线衍射, C-S-H凝胶, 固井